Battery string cold soldering detection device, detection method and string soldering machine

Abstract

The present invention provides a battery string cold soldering detection device, a detection method and a string soldering machine, wherein the battery string cold soldering detection device comprises a battery cell conduction mechanism and an infrared imaging mechanism, wherein: the battery cell conduction mechanism is used to conduct adjacent battery cells in the battery string; the infrared imaging mechanism is arranged below the battery cell conduction mechanism, and the infrared imaging mechanism is used to obtain infrared images of adjacent battery cells that are conducted to obtain cold soldering points on adjacent battery cells. The present invention only conducts electricity on a pair of adjacent battery cells on the battery string at a time, and the infrared imaging mechanism only obtains infrared images of a pair of adjacent battery cells at a time, and finally implements cold soldering point detection on the entire battery string through multiple electrical conductions and photographing. Compared with the traditional EL detection method, the present invention can greatly improve the detection accuracy of cold soldering points.

Description

Technical Field

[0001] The invention relates to the field of battery production, in particular to a battery string cold soldering detection device, a detection method and a string soldering machine. Background Art

[0002] After the cells are welded into strings by the welding ribbon group, the cold solder joints on the cell string are detected by the EL (electroluminescence) detection method. The traditional EL detection method connects the head welding ribbon and the tail welding ribbon at both ends of the cell string to the positive and negative electrodes of the DC power supply respectively to electrically conduct the entire cell string, and the infrared imaging device obtains the infrared image of the entire cell string, and the cold solder joints on the cell string are detected by dark spot analysis of the infrared image.

[0003] The traditional EL detection method is suitable for detecting cold solder joints of traditional battery strings with 4-6 main busbars. With the development of battery technology, the number of main busbars in existing battery strings has increased to 9-20, or even more. The increase in main busbars may cause the dark spots in the infrared image of the battery string to cover the solder strips on multiple main busbars, making it impossible to accurately obtain cold solder joints. Summary of the invention

[0004] In order to solve the above technical problems, the first aspect of the present invention provides a battery string cold solder joint detection device, which is used to detect the cold solder joint of a battery string, wherein the battery string is formed by welding a plurality of battery cells in sequence through a welding ribbon group. The battery string cold solder joint detection device includes a battery cell conduction mechanism and an infrared imaging mechanism, wherein:

[0005] The battery cell conduction mechanism is used to electrically conduct adjacent battery cells in a battery string;

[0006] The infrared imaging mechanism is arranged below the battery cell conduction mechanism, and is used to obtain infrared images of adjacent battery cells that are conducted to obtain cold solder joints on the adjacent battery cells.

[0007] The battery string cold solder joint detection device of the present invention only electrically conducts a pair of adjacent battery cells on the battery string at a time, and the infrared imaging mechanism only obtains infrared images of a pair of adjacent battery cells at a time, and finally implements cold solder joint detection of the entire battery string through multiple electrical conductions and photographing. Compared with traditional detection methods, the present invention can greatly improve the detection accuracy of cold solder joints.

[0008] In some embodiments, each pair of adjacent battery cells includes adjacent front battery cells and rear battery cells, and the battery cell conduction mechanism includes a mounting bracket and at least one group of battery cell conduction components arranged on the mounting bracket, wherein the battery cell conduction components include: a positive electrode contact head connected to the positive pole of a DC power supply, the positive electrode contact head is configured to press the welding ribbon group welded on the positive electrode of the front battery cell in the adjacent battery cells to electrically connect the positive electrode of the front battery cell and the positive pole of the DC power supply; a negative electrode contact head connected to the negative pole of the DC power supply, the negative electrode contact head is configured to press the welding ribbon group welded on the negative electrode of the rear battery cell in the adjacent battery cells to electrically connect the negative electrode of the rear battery cell and the negative pole of the DC power supply.

[0009] A battery cell conduction mechanism with simple structure and convenient operation is provided, which implements electrical conduction of adjacent battery cells through a battery cell conduction assembly including positive and negative electrode contacts.

[0010] In some embodiments, a group of battery cell conduction components are disposed on the mounting bracket, and the battery cell conduction components are stepped along the extension direction of the battery string and electrically conduct each pair of adjacent battery cells in the battery string in turn.

[0011] By providing a group of battery cell conduction components, each pair of adjacent battery cells in the battery string can be electrically connected one by one, thereby reducing the cost of the battery cell conduction mechanism.

[0012] In some embodiments, a plurality of groups of battery cell conduction components arranged along the extension direction of the battery string are disposed on the mounting bracket, and each group of battery cell conduction components can electrically conduct a pair of adjacent battery cells.

[0013] By setting up multiple groups of battery cell conduction components, multiple pairs of adjacent battery cells can be electrically connected in sequence and continuously without moving the mounting bracket, thereby improving the detection efficiency.

[0014] In some embodiments, the cell conduction assembly further includes a suction assembly for sucking a pair of adjacent cell sheets so that the positive electrode contact head and the negative electrode contact head are respectively pressed against corresponding welding ribbon groups on the sucked adjacent cell sheets.

[0015] By providing the suction assembly, the positive electrode contact head and the negative electrode contact head can be automatically pressed onto the corresponding welding ribbon group on the adjacent battery sheet.

[0016] In some embodiments, the suction assembly includes a first suction cup group and a second suction cup group, wherein the first suction cup group is used to absorb the front battery cell among adjacent battery cells, and the second suction cup group is used to absorb the rear battery cell among adjacent battery cells.

[0017] By setting the suction assembly as the first suction cup group and the second suction cup group, it is possible to implement synchronous suction of two adjacent battery cells, thereby ensuring that the positive electrode contact head and the negative electrode contact head are pressed onto the corresponding welding ribbon group.

[0018] In some embodiments, each welding strip group includes M welding strips. The positive electrode contact head and the negative electrode contact head each include M pressure pins, the spacing between adjacent pressure pins is equal to the spacing between adjacent welding strips, and the positive electrode contact head and the negative electrode contact head press all welding strips in the corresponding welding strip group. Alternatively, the positive electrode contact head and the negative electrode contact head each include M / 2 or (M+1) / 2 pressure pins, the spacing between adjacent pressure pins is equal to twice the spacing between adjacent welding strips, and the positive electrode contact head and the negative electrode contact head respectively press all odd-numbered welding strips in the corresponding welding strip group, or respectively press all even-numbered welding strips in the corresponding welding strip group.

[0019] Two different implementations of the positive electrode contact head and the negative electrode contact head are provided, wherein, in the first implementation, the number of pressure pins included in the positive electrode contact head and the negative electrode contact head is equal to the number of welding strips included in the welding strip group, so the positive electrode contact head and the negative electrode contact head can realize simultaneous electrical conduction of all welding strips, thereby performing simultaneous detection of all welding strips in the welding strip group at one time. In the second implementation, the number of pressure pins included in the positive electrode contact head and the negative electrode contact head is half the number of welding strips included in the welding strip group, so the positive electrode contact head and the negative electrode contact head only electrically conduct all odd welding strips or all even welding strips in the welding strip group at one time, so the positive electrode contact head and the negative electrode contact head need to perform two electrical conduction operations to complete the electrical conduction of all welding strips in the welding strip group, but compared with the first implementation, since the spacing between the electrically conducted welding strips is increased, the situation in which the dark spots cover the welding strips on multiple main grid lines in the formed infrared image is further improved, thereby further improving the detection accuracy of the cold solder joints of the present invention.

[0020] In some embodiments, the battery cell conduction mechanism further includes a moving mechanism, the mounting bracket is connected to a driving end of the moving mechanism, and the moving mechanism is used to drive the mounting bracket to move, thereby driving the battery cell conduction assembly to move.

[0021] By setting the moving mechanism, the driving of the battery cell conduction component is realized.

[0022] In some embodiments, the infrared imaging mechanism includes a dark box and an infrared camera disposed in the dark box.

[0023] By placing the infrared camera in a dark box, the infrared imaging effect is improved.

[0024] A second aspect of the present invention provides a battery string cold solder joint detection method for realizing cold solder joint detection of a battery string, the battery string cold solder joint detection method comprising:

[0025] Controlling the battery cell conduction mechanism to electrically conduct adjacent battery cells in the battery string;

[0026] The infrared imaging mechanism is controlled to obtain infrared images of the electrically connected adjacent battery cells to obtain the cold solder joints on the adjacent battery cells.

[0027] The battery string cold solder joint detection method of the present invention only electrically conducts a pair of adjacent battery cells on the battery string at a time, and the infrared imaging mechanism only obtains infrared images of a pair of adjacent battery cells at a time, and finally implements cold solder joint detection of the entire battery string through multiple electrical conductions and photographing. Compared with traditional detection methods, the present invention can greatly improve the detection accuracy of cold solder joints.

[0028] In some embodiments, the battery cell conduction mechanism includes a mounting bracket and at least one group of battery cell conduction components arranged on the mounting bracket; controlling the battery cell conduction mechanism to sequentially electrically conduct adjacent battery cells in the battery string includes: sequentially controlling the battery cell conduction components to electrically conduct a pair of adjacent battery cells.

[0029] By providing a group of battery cell conduction components, each pair of adjacent battery cells in the battery string can be electrically connected one by one, thereby reducing the cost of the battery cell conduction mechanism.

[0030] In some embodiments, the battery cell conduction component includes a positive electrode contact head connected to the positive pole of a DC power supply and a negative electrode contact head connected to the negative pole of the DC power supply; sequentially controlling the battery cell conduction component to electrically conduct a pair of adjacent battery cells includes: each time the battery cell conduction component is controlled to electrically conduct a pair of adjacent battery cells, controlling the positive electrode contact head of the battery cell conduction component to press the welding ribbon group welded on the positive electrode of the front battery cell in the adjacent battery cells to connect the positive electrode of the front battery cell and the positive pole of the DC power supply, and controlling the negative electrode contact head of the battery cell conduction component to press the welding ribbon group welded on the negative electrode of the rear battery cell in the adjacent battery cell to connect the negative electrode of the rear battery cell and the negative pole of the DC power supply.

[0031] A battery cell conduction mechanism with simple structure and convenient operation is provided, which implements electrical conduction of adjacent battery cells through a battery cell conduction assembly including positive and negative electrode contacts.

[0032] In some embodiments, a group of battery cell conduction components are provided on the mounting bracket, and controlling the battery cell conduction mechanism to electrically conduct adjacent battery cells in the battery string in sequence includes: controlling the battery cell conduction component to move stepwise along the extension direction of the battery cell, so that the battery cell conduction component electrically conducts each pair of adjacent battery cells in the battery string in sequence.

[0033] By providing a group of battery cell conduction components, each pair of adjacent battery cells in the battery string can be electrically connected one by one, thereby reducing the cost of the battery cell conduction mechanism.

[0034] In some embodiments, a plurality of battery cell conduction components are arranged in a straight line along the extension direction of the battery string on the mounting bracket, and controlling the battery cell conduction mechanism to sequentially electrically conduct adjacent battery cells in the battery string includes: controlling each battery cell conduction component to sequentially electrically conduct a pair of adjacent battery cells.

[0035] By setting up multiple groups of battery cell conduction components, multiple pairs of adjacent battery cells can be electrically connected in sequence and continuously without moving the mounting bracket, thereby improving the detection efficiency.

[0036] In some embodiments, each welding strip group includes M welding strips, and the positive electrode contact head and the negative electrode contact head each include M pressure pins, and the spacing between adjacent pressure pins is equal to the spacing between adjacent welding strips. Sequentially controlling the battery cell conduction assembly to electrically conduct a pair of adjacent battery cells includes: controlling the positive electrode contact head and the negative electrode contact head to respectively press the welding strips in the corresponding welding strip group on the adjacent battery cells, wherein each pressure pin presses one welding strip.

[0037] The number of pressure pins included in the positive electrode contact head and the negative electrode contact head is equal to the number of welding strips included in the welding strip group. Therefore, the positive electrode contact head and the negative electrode contact head can achieve simultaneous electrical conduction of all welding strips, thereby implementing simultaneous electrical conduction and detection of all welding strips in the welding strip group at one time, thereby improving the detection efficiency.

[0038] In some embodiments, each welding strip group includes M welding strips, and the positive electrode contact head and the negative electrode contact head each include M / 2 or (M+1) / 2 pressure pins, and the spacing between adjacent pressure pins is equal to twice the spacing between adjacent welding strips. Sequentially controlling the battery cell conduction assembly to electrically conduct a pair of adjacent battery cells includes: controlling the positive electrode contact head and the negative electrode contact head to respectively press all the odd-numbered welding strips in the corresponding welding strip group on the adjacent battery cells; and controlling the positive electrode contact head and the negative electrode contact head to respectively press all the even-numbered welding strips in the corresponding welding strip group on the adjacent battery cells, wherein each pressure pin presses one welding strip.

[0039] The number of pressure pins included in the positive electrode contact head and the negative electrode contact head is half the number of welding strips included in the welding strip group. Therefore, the positive electrode contact head and the negative electrode contact head only electrically conduct all odd-numbered welding strips or all even-numbered welding strips in the welding strip group at one time. Therefore, the positive electrode contact head and the negative electrode contact head need to perform two conduction operations to complete the conduction and detection of all welding strips in the welding strip group. However, since the spacing between adjacent welding strips that are conducted is increased, the situation in which dark spots cover the welding strips on multiple main grid lines in the infrared image formed by this embodiment is further improved, thereby further improving the detection accuracy of the present invention for the virtual solder joints.

[0040] The third aspect of the present invention provides a string welding machine, which includes a battery cell feeding device, a welding strip feeding device, a welding conveying device, a welding device and any one of the battery string cold welding detection devices described above, wherein:

[0041] The solder ribbon feeding device and the battery cell feeding device stack the solder ribbon and the battery cell on the welding conveying device, and the welding conveying device sequentially transports the stacked solder ribbon and the battery cell to the welding station and the inspection station;

[0042] The welding device welds the welding ribbon and the battery sheet together to form a battery string;

[0043] The battery string cold solder joint detection device implements cold solder joint detection on the battery string.

[0044] With the cooperation of the battery cell feeding device, the welding strip feeding device, the welding conveying device, the welding device and the battery string cold solder joint detection device, the present invention completes the cold solder joint detection of the battery string after completing the battery string welding, which significantly improves the production efficiency of the battery string. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a structural schematic diagram of a battery string cold soldering detection device of the present invention;

[0046] Figure 2 It is a schematic diagram of the electrical conduction of a pair of adjacent battery cells in a battery string by the battery cell conduction mechanism of the present invention;

[0047] Figure 1 to Figure 2 Included:

[0048] A cell conduction mechanism 10, a mounting bracket 11, a cell conduction assembly 12, a positive electrode contact head 121, a negative electrode contact head 122, a first suction cup group 123, and a second suction cup group 124;

[0049] Infrared imaging mechanism 20 , dark box 21 , infrared camera 22 . DETAILED DESCRIPTION

[0050] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0051] The traditional EL detection method is suitable for detecting cold solder joints of traditional battery strings with 4-6 main busbars. With the development of battery technology, the number of main busbars in existing battery strings has increased to 9-20, or even more. The increase in main busbars may cause the dark spots in the infrared image of the battery string to cover the solder strips on multiple main busbars, making it impossible to accurately obtain cold solder joints.

[0052] In view of this, the present invention provides a battery string cold solder joint detection device and detection method to realize cold solder joint detection of a battery string, wherein the battery string is formed by welding a plurality of battery cells in sequence via a welding ribbon group.

[0053] The battery string cold solder joint detection device and the battery string cold solder joint detection method provided by the present invention will be respectively introduced exemplarily through two embodiments below.

[0054] First embodiment

[0055] like Figure 1 As shown, the battery string cold soldering detection device provided in this embodiment includes a battery cell conduction mechanism 10 and an infrared imaging mechanism 20, wherein:

[0056] The battery cell conducting mechanism 10 is used to electrically conduct adjacent battery cells in a battery string.

[0057] The infrared imaging mechanism 20 is arranged below the battery cell conduction mechanism 10, and is used to obtain infrared images of the adjacent battery cells that are conducted, and to detect and locate the cold solder joints (i.e., the locations of the cold solder strips) on the adjacent battery cells by detecting dark spots in the infrared images.

[0058] Since the cell conduction mechanism 10 only conducts electrical conduction to a pair of adjacent cells in the battery string each time, the infrared imaging mechanism 20 only acquires infrared images of the electrically conducted adjacent cells each time.

[0059] Therefore, the number of solder strips included in the infrared image is relatively small, and the situation where dark spots cover the solder strips on multiple main grid lines is greatly improved, thereby improving the accuracy of cold solder joint detection.

[0060] like Figure 1 and Figure 2 As shown, each pair of adjacent cells in the battery string includes an adjacent front cell 101 and a rear cell 102. Optionally, the cell conduction mechanism includes a mounting bracket 11 and at least one group of cell conduction components 12 disposed on the mounting bracket 11, and each group of cell conduction components 12 includes a positive electrode contact head 121 and a negative electrode contact head 122, wherein:

[0061] The positive electrode contact head 121 is connected to the positive electrode of the DC power supply and is used to press the welding ribbon group welded on the positive electrode of the previous battery cell 101 in the adjacent battery cell to electrically connect the positive electrode of the previous battery cell 101 and the positive electrode of the DC power supply.

[0062] The negative electrode contact head 122 is connected to the negative electrode of the DC power supply and is used to press the welding ribbon group welded on the negative electrode of the rear battery cell 102 in the adjacent battery cell to electrically connect the negative electrode of the rear battery cell 102 and the negative electrode of the DC power supply.

[0063] In this way, the front battery cell 101, the rear battery cell 102 and the DC power supply form a conductive loop, and the soldering ribbons with qualified welding in the soldering ribbon group are in a conductive state, the current flowing through the soldering ribbons is large, and they are brighter in the infrared image and have a higher temperature, so their brightness in the infrared image is higher. The soldering ribbons with unqualified welding are in a non-conductive state, the current flowing through them is small, and the temperature is low, so they appear as dark spots with low brightness in the infrared image.

[0064] Optionally, only one set of cell conduction components 12 is provided on the mounting bracket 11, and the cell conduction components 12 step along the extension direction of the battery string, and each stepping distance is substantially equal to the sum of the lengths of a pair of adjacent cells. In this way, after each stepping, the cell conduction components electrically conduct a pair of adjacent cells, and the infrared imaging mechanism 20 then acquires an infrared image to complete the detection of the cold soldering strips on the adjacent cells that are currently electrically conducted.

[0065] Optionally, the mounting bracket 11 is provided with a plurality of groups of cell conduction components 12 arranged along the extension direction of the battery string, and each group of cell conduction components 12 can electrically conduct a pair of adjacent cells. In this way, without moving the mounting bracket 11, the cell conduction mechanism can implement sequential and continuous electrical conduction of multiple pairs of adjacent cells, thereby improving the detection efficiency. Of course, at the same time, it is necessary to ensure that only one group of cell conduction components 12 performs the electrical conduction operation, that is, at the same time, only one pair of adjacent cells is in an electrically conductive state.

[0066] like Figure 1 As shown, in order to further improve the detection efficiency, the number of cell conduction components 12 can be set to be equal to the number of pairs of adjacent cells included in the battery string. In this way, there is a corresponding set of cell conduction components 12 above each pair of adjacent cells in the battery string, and there is no need to move the mounting bracket 11 during the entire detection period.

[0067] Optionally, the battery cell conduction component 12 also includes a suction component. When the battery cell conduction component 12 is located above the adjacent battery cell that currently needs to be electrically conductive, the suction component sucks the current adjacent battery cell upward, so that the positive electrode contact head 121 and the negative electrode contact head 122 are respectively pressed on the corresponding welding ribbon groups on the sucked adjacent battery cell.

[0068] like Figure 1 and Figure 2 As shown, optionally, the suction assembly includes a first suction cup group 123 and a second suction cup group 124 arranged between the positive electrode contact head 121 and the negative electrode contact head 122, wherein the first suction cup group 123 is used to absorb the front battery cell 101 among adjacent battery cells, and the second suction cup group 124 is used to absorb the rear battery cell 102 among adjacent battery cells.

[0069] As is well known in the art, the number of welding strips (set as M) included in the welding strip group connecting the battery cells is equal to the number of main grid lines on the battery cells. Optionally, the battery cell conducting component 12 can select the following two implementations for conducting electricity to adjacent battery cells:

[0070] The first implementation method:

[0071] The positive electrode contact head 121 and the negative electrode contact head 122 each include M pressure pins, the spacing between adjacent pressure pins is equal to the spacing between adjacent welding strips, the positive electrode contact head 11 and the negative electrode contact head 122 press all welding strips in the corresponding welding strip group, wherein each pressure pin presses one welding strip.

[0072] In this embodiment, the number of pressure pins included in the positive electrode contact head 121 and the negative electrode contact head 122 is equal to the number of solder strips included in the solder strip group. Therefore, the battery cell conduction component 12 can achieve simultaneous electrical conduction of all solder strips in the solder strip group on adjacent battery cells, thereby improving detection efficiency.

[0073] Second implementation method

[0074] When the number M of welding strips included in the welding strip group is an even number, the positive electrode contact head 121 and the negative electrode contact head 122 both include M / 2 pressure pins. When the number M of welding strips included in the welding strip group is an odd number, the positive electrode contact head 121 and the negative electrode contact head 122 both include (M+1) / 2 pressure pins.

[0075] The spacing between adjacent pressure pins is equal to twice the spacing between adjacent solder strips.

[0076] In this embodiment, the battery cell conduction component 12 performs the electrical conduction operation in two steps.

[0077] In the first step, the positive electrode contact head 121 and the negative electrode contact head 122 respectively press all the odd-numbered welding strips in the corresponding welding strip group, such as Figure 2 After completing the electrical conduction of all the odd-numbered welding strips, the infrared imaging mechanism 20 acquires an infrared image and detects the cold-welded welding strips in all the odd-numbered welding strips.

[0078] In the second step, the positive electrode contact head 121 and the negative electrode contact head 122 respectively press the even-numbered welding strips in the corresponding welding strip group, such as Figure 2 After completing the electrical conduction of all the even-numbered solder strips, the infrared imaging mechanism 20 acquires another infrared image and detects the cold solder strips in all the even-numbered solder strips.

[0079] Of course, it is also possible that the first step is to electrically connect all the even-numbered welding strips, and the second step is to electrically connect all the odd-numbered welding strips.

[0080] Compared with the first embodiment, the present embodiment needs to perform two electrical conduction operations to complete the electrical conduction and detection of all the welding strips in the welding strip group. However, compared with the first embodiment, since the spacing between the electrically conducted welding strips is doubled, the situation in which dark spots cover the welding strips on multiple main grid lines in the formed infrared image will inevitably be further improved, thereby further improving the detection accuracy of cold solder joints.

[0081] Optionally, the cell conduction mechanism 10 further includes a moving mechanism, the mounting bracket 11 is connected to the driving end of the moving mechanism, and the moving mechanism 11 drives the mounting bracket to move, thereby driving the cell conduction assembly 12 to move, so as to implement electrical conduction of adjacent cells in the battery string.

[0082] like Figure 2 As shown, optionally, the infrared imaging mechanism 20 includes a dark box 21 and an infrared camera 22 disposed in the dark box 21. By disposing the infrared camera 22 in the dark box 21, the infrared imaging effect of the infrared camera 22 on the battery cell can be improved.

[0083] Second embodiment

[0084] The battery string cold soldering detection method provided in this embodiment can be implemented by the battery string cold soldering detection device in the first embodiment described above. Specifically, Figure 1 and Figure 2 As shown, the battery string cold soldering detection method includes:

[0085] The battery cell conduction mechanism 10 is controlled to electrically conduct adjacent battery cells in a battery string.

[0086] The infrared imaging mechanism 20 is controlled to obtain infrared images of the electrically connected adjacent battery cells to obtain the cold solder joints on the adjacent battery cells.

[0087] Since the cell conduction mechanism 10 only conducts electrical conduction to a pair of adjacent cells in the battery string each time, the infrared imaging mechanism 20 only acquires infrared images of a pair of adjacent cells that are electrically conducted each time.

[0088] Therefore, the number of solder strips in the infrared image is smaller, and the situation where dark spots cover the solder strips on multiple main grid lines is greatly improved, thereby ultimately improving the accuracy of cold solder joint detection.

[0089] Optionally, the cell conduction mechanism 10 includes a mounting bracket 11 and at least one group of cell conduction components 12 disposed on the mounting bracket 11. Controlling the cell conduction mechanism 10 to sequentially electrically conduct adjacent cells in a battery string includes: sequentially controlling the cell conduction components to electrically conduct a pair of adjacent cells in the battery string.

[0090] Optionally, the cell conduction assembly 12 includes a positive electrode contact head 121 connected to the positive electrode of the DC power supply and a negative electrode contact head 122 connected to the negative electrode of the DC power supply. The cell conduction assembly is sequentially controlled to electrically conduct a pair of adjacent cell sheets, specifically:

[0091] Each time the battery cell conduction component 12 is controlled to electrically conduct a pair of adjacent battery cells, the positive electrode contact head 121 of the battery cell conduction component 12 is controlled to press the welding ribbon group welded on the positive electrode of the front battery cell 101 in the adjacent battery cell to connect the positive electrode of the front battery cell 101 and the positive electrode of the DC power supply, and the negative electrode contact head 122 of the battery cell conduction component 12 is controlled to press the welding ribbon group welded on the negative electrode of the rear battery cell 102 in the adjacent battery cell to connect the negative electrode of the rear battery cell 102 and the negative electrode of the DC power supply.

[0092] In this way, the front battery cell 101, the rear battery cell 102 and the DC power supply form a conductive loop, and the soldering ribbons with qualified soldering in the soldering ribbon group are in a conductive state and have a higher temperature, so their brightness in the infrared image is higher. The soldering ribbons with unqualified soldering are in a non-conductive state and have a lower temperature, so they appear as dark spots with lower brightness in the infrared image.

[0093] Optionally, a group of battery cell conduction components 12 are provided on the mounting bracket 11. In this case, the implementation method of controlling the battery cell conduction mechanism 10 to electrically conduct adjacent battery cells in the battery string in turn is: controlling the battery cell conduction component 12 to move stepwise along the extension direction of the battery cell, so that the battery cell conduction component 12 electrically conducts each pair of adjacent battery cells in the battery string in turn.

[0094] Of course, the stepping distance of the cell conducting component 12 each time needs to be roughly equal to the length of a pair of adjacent cells. In this way, after each stepping, the cell conducting component electrically conducts a pair of adjacent cells, and the infrared imaging mechanism 20 then obtains an infrared image to complete the detection of the cold soldering strips on the adjacent cells that are currently electrically conducted.

[0095] Optionally, the mounting bracket 11 is provided with a plurality of groups of battery cell conduction components 12 arranged in a straight line along the extension direction of the battery string. In this case, the implementation method of controlling the battery cell conduction mechanism 10 to electrically conduct adjacent battery cells in the battery string in turn is: controlling each battery cell conduction component to electrically conduct a pair of adjacent battery cells in turn.

[0096] In this way, without moving the mounting bracket 11, the battery cell conduction mechanism can implement sequential and continuous electrical conduction of multiple pairs of adjacent battery cells, thereby improving the detection efficiency. Of course, at the same time, it is necessary to ensure that only one group of battery cell conduction components 12 performs the electrical conduction operation, that is, at the same time, only one pair of adjacent battery cells is in an electrically conductive state.

[0097] As is well known in the art, the number of welding strips (set as M) included in the welding strip group connecting the battery cells is equal to the number of main grid lines on the battery cells. Optionally, controlling the battery cell conduction component 12 to electrically conduct adjacent battery cells can be implemented in the following two embodiments:

[0098] The first implementation method:

[0099] The positive electrode contact head 121 and the negative electrode contact head 122 each include M pressure pins, and the spacing between adjacent pressure pins is equal to the spacing between adjacent welding strips.

[0100] In this case, the cell conduction component 12 is controlled to electrically conduct adjacent cells, specifically:

[0101] The positive electrode contact head 121 and the negative electrode contact head 122 are controlled to respectively press the welding strips in the corresponding welding strip groups on the adjacent battery cells, wherein each pressing needle presses one welding strip.

[0102] In this embodiment, the number of pressure pins included in the positive electrode contact head 121 and the negative electrode contact head 122 is equal to the number of solder strips included in the solder strip group. Therefore, the battery cell conduction component 12 can achieve simultaneous electrical conduction of all solder strips in the solder strip group on adjacent battery cells, thereby improving detection efficiency.

[0103] Second implementation method

[0104] When the number M of welding strips included in the welding strip group is an even number, the positive electrode contact head 121 and the negative electrode contact head 122 both include M / 2 pressure pins. When the number M of welding strips included in the welding strip group is an odd number, the positive electrode contact head 121 and the negative electrode contact head 122 both include (M+1) / 2 pressure pins.

[0105] The spacing between adjacent pressure pins is equal to twice the spacing between adjacent solder strips.

[0106] In this case, the cell conduction component 12 is controlled to electrically conduct adjacent cells, specifically:

[0107] In the first step, the positive electrode contact head 121 and the negative electrode contact head 122 are controlled to respectively press all odd-numbered welding strips in the corresponding welding strip group, such as Figure 2 After completing the electrical conduction of all the odd-numbered welding strips, the infrared imaging mechanism 20 acquires an infrared image and detects the cold-welded welding strips in all the odd-numbered welding strips.

[0108] In the second step, the positive electrode contact head 121 and the negative electrode contact head 122 are controlled to respectively press the even-numbered welding strips in the corresponding welding strip group, such as Figure 2 After completing the electrical conduction of all the even-numbered solder strips, the infrared imaging mechanism 20 acquires an infrared image and detects the cold solder strips in all the even-numbered solder strips.

[0109] Of course, it is also possible that the first step is to electrically connect all the even-numbered welding strips, and the second step is to electrically connect all the odd-numbered welding strips.

[0110] Compared with the first embodiment, the present embodiment needs to perform two electrical conduction operations to complete the electrical conduction and detection of all the welding strips in the welding strip group. However, compared with the first embodiment, since the spacing between the electrically conducted welding strips is doubled, the situation in which dark spots cover the welding strips on multiple main grid lines in the formed infrared image will inevitably be further improved, thereby further improving the detection accuracy of cold solder joints.

[0111] Finally, the present invention also provides a string welding machine, which includes a battery cell feeding device, a welding strip feeding device, a welding conveying device, a welding device, and a battery string cold welding detection device as described in any one of the above items, wherein: the welding strip feeding device and the battery cell feeding device stack the welding strip and the battery cell on the welding conveying device, and the welding conveying device sequentially transports the stacked welding strip and the battery cell to the welding station and the detection station. The welding device welds the welding strip and the battery cell together to form a battery string. The battery string cold welding detection device performs cold welding detection on the battery string.

[0112] With the cooperation of the battery cell feeding device, the welding strip feeding device, the welding conveying device, the welding device and the battery string cold solder joint detection device, the present invention completes the cold solder joint detection of the battery string after completing the battery string welding, which significantly improves the production efficiency of the battery string.

[0113] The present invention has been described in sufficient detail with certain particularity. It should be understood by those skilled in the art that the description in the embodiments is merely exemplary, and all changes made without departing from the true spirit and scope of the present invention should fall within the scope of protection of the present invention. The scope of protection claimed by the present invention is defined by the claims, rather than by the above description in the embodiments.

Claims

1. A battery string cold solder joint detection device, used to realize cold solder joint detection of a battery string, wherein the battery string is formed by welding a plurality of battery cells in sequence through a welding ribbon group, characterized in that: The battery string cold soldering detection device comprises a battery cell conduction mechanism and an infrared imaging mechanism, wherein: The battery cell conduction mechanism is used to electrically conduct adjacent battery cells in the battery string; The infrared imaging mechanism is arranged below the battery cell conduction mechanism, and is used to obtain infrared images of the adjacent battery cells that are conducted to obtain the cold solder joints on the adjacent battery cells; Each pair of adjacent battery cells includes an adjacent front battery cell and a rear battery cell, and the battery cell conduction mechanism includes a mounting bracket and at least one set of battery cell conduction components arranged on the mounting bracket, wherein the battery cell conduction components include: A positive electrode contact head connected to the positive electrode of a DC power source, wherein the positive electrode contact head is configured to press a welding ribbon group welded on the positive electrode of a preceding battery cell among the adjacent battery cells to electrically connect the positive electrode of the preceding battery cell and the positive electrode of the DC power source; A negative electrode contact head connected to the negative electrode of the DC power supply, wherein the negative electrode contact head is configured to press a welding ribbon group welded on the negative electrode of the rear battery cell in the adjacent battery cell to electrically connect the negative electrode of the rear battery cell and the negative electrode of the DC power supply.

2. The battery string cold soldering detection device according to claim 1, characterized in that: A group of the battery cell conduction components are arranged on the mounting frame, and the battery cell conduction components move stepwise along the extension direction of the battery string, and electrically conduct each pair of adjacent battery cells in the battery string in turn.

3. The battery string cold soldering detection device according to claim 1, characterized in that: The mounting bracket is provided with a plurality of groups of the battery cell conducting components arranged along the extension direction of the battery string, and each group of the battery cell conducting components can electrically conduct a pair of adjacent battery cells.

4. The battery string cold soldering detection device according to claim 1, characterized in that: The battery cell conduction component also includes a suction component, which is used to suck a pair of adjacent battery cells so that the positive electrode contact head and the negative electrode contact head are respectively pressed on the corresponding welding ribbon groups on the sucked adjacent battery cells.

5. The battery string cold soldering detection device as claimed in claim 4, characterized in that: The suction assembly includes a first suction cup group and a second suction cup group, wherein the first suction cup group is used to absorb the front battery cell among the adjacent battery cells, and the second suction cup group is used to absorb the rear battery cell among the adjacent battery cells.

6. The battery string cold soldering detection device according to claim 1, characterized in that: Each of the welding ribbon groups includes M welding ribbons; The positive electrode contact head and the negative electrode contact head each include M pressure pins, the spacing between adjacent pressure pins is equal to the spacing between adjacent welding strips, and the positive electrode contact head and the negative electrode contact head press all the welding strips in the corresponding welding strip group; or, The positive electrode contact head and the negative electrode contact head each include M / 2 or (M+1) / 2 pressure pins, the spacing between adjacent pressure pins is equal to twice the spacing between adjacent welding strips, and the positive electrode contact head and the negative electrode contact head respectively press all the odd-numbered welding strips in the corresponding welding strip group, or respectively press all the even-numbered welding strips in the corresponding welding strip group.

7. The battery string cold soldering detection device according to claim 1, characterized in that: The battery cell conduction mechanism also includes a moving mechanism, the mounting bracket is connected to the driving end of the moving mechanism, and the moving mechanism is used to drive the mounting bracket to move, so as to drive the battery cell conduction assembly to move.

8. The battery string cold soldering detection device according to claim 1, characterized in that: The infrared imaging mechanism comprises a dark box and an infrared camera arranged in the dark box.

9. A method for detecting cold solder joints in a battery string, for realizing cold solder joint detection in a battery string, wherein the battery string is formed by welding a plurality of battery cells in sequence through a welding ribbon group, and wherein: The battery string cold soldering detection method comprises: Controlling the battery cell conduction mechanism to electrically conduct adjacent battery cells in the battery string in sequence; After each electrical connection of adjacent battery cells, the infrared imaging mechanism is controlled to obtain infrared images of the electrically connected adjacent battery cells to obtain cold solder joints on the adjacent battery cells; The battery cell conduction mechanism comprises a mounting bracket and at least one set of battery cell conduction components arranged on the mounting bracket; The controlling the battery cell conduction mechanism to electrically conduct adjacent battery cells in the battery string in sequence comprises: sequentially controlling the battery cell conduction component to electrically conduct a pair of adjacent battery cells; The battery cell conduction assembly includes a positive electrode contact head connected to the positive electrode of the DC power supply and a negative electrode contact head connected to the negative electrode of the DC power supply; The sequentially controlling the battery cell conduction components to electrically conduct a pair of adjacent battery cells comprises: Each time the cell conduction assembly is controlled to electrically conduct a pair of adjacent cells, the positive electrode contact head of the cell conduction assembly is controlled to press the welding ribbon group welded on the positive electrode of the preceding cell among the adjacent cells, so as to connect the positive electrode of the preceding cell with the positive electrode of the DC power supply; The negative electrode contact head of the battery cell conduction assembly is controlled to press the welding ribbon group welded on the negative electrode of the subsequent battery cell in the adjacent battery cell to connect the negative electrode of the subsequent battery cell and the negative electrode of the DC power supply.

10. The battery string cold soldering detection method according to claim 9, characterized in that: The mounting bracket is provided with a group of the battery cell conduction components, and the control battery cell conduction mechanism sequentially conducts the adjacent battery cells in the battery string, including: The battery cell conducting component is controlled to move stepwise along the extending direction of the battery cell, so that the battery cell conducting component electrically conducts each pair of adjacent battery cells in the battery string in turn.

11. The battery string cold soldering detection method according to claim 9, characterized in that: The mounting bracket is provided with a plurality of battery cell conduction components arranged in a straight line along the extension direction of the battery string, and the battery cell conduction control mechanism sequentially electrically conducts adjacent battery cells in the battery string, including: Each of the battery cell conduction components is controlled to electrically conduct a pair of adjacent battery cells in sequence.

12. The battery string cold soldering detection method according to claim 9, characterized in that: Each of the welding strip groups includes M welding strips, and the positive electrode contact head and the negative electrode contact head each include M pressure pins, and the spacing between adjacent pressure pins is equal to the spacing between adjacent welding strips; The sequentially controlling the battery cell conduction components to electrically conduct a pair of adjacent battery cells comprises: The positive electrode contact head and the negative electrode contact head are controlled to respectively press all the welding strips in the corresponding welding strip group on the adjacent battery cells, wherein each of the pressing needles presses one welding strip.

13. The battery string cold soldering detection method according to claim 9, characterized in that: Each of the welding strip groups includes M welding strips, and the positive electrode contact head and the negative electrode contact head each include M / 2 or (M+1) / 2 pressure pins, and the spacing between adjacent pressure pins is equal to twice the spacing between adjacent welding strips; The sequentially controlling the battery cell conduction components to electrically conduct a pair of adjacent battery cells comprises: Controlling the positive electrode contact head and the negative electrode contact head to respectively press all odd-numbered welding strips in the corresponding welding strip group on the adjacent battery cells; and The positive electrode contact head and the negative electrode contact head are controlled to respectively press all even-numbered welding strips in the corresponding welding strip group on the adjacent battery cells, wherein each of the pressing needles presses one welding strip.

14. A string welding machine, characterized in that: The string welding machine comprises a battery cell feeding device, a welding strip feeding device, a welding conveying device, a welding device and a battery string cold welding detection device according to any one of claims 1 to 8, wherein: The solder strip feeding device and the battery cell feeding device stack the solder strips and the battery cells on the welding conveying device, and the welding conveying device sequentially transports the stacked solder strips and the battery cells to the welding station and the inspection station; The welding device welds the welding ribbon and the battery sheet together to form a battery string; The battery string cold solder joint detection device implements cold solder joint detection on the battery string.

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