Online detection method and device for connection condition of metal busbar of battery pack

Abstract

The invention provides an online detection method and device for the connection condition of a metal busbar of a battery pack, and the method comprises the steps: in the operation process of fastening the metal busbar through a bolt, when the bolt torque is monitored to reach a preset torque value, carrying out the detection of the connection condition of the metal busbar of the battery pack; measuring distance values L1 and L2 from the preset position to the upper surfaces of the two metal busbars, and calculating a gap value L'of the two metal busbars based on the distance values L1 and L2; and judging whether the gap value L'is within a preset standard value range L'min-L'max or not, if not, judging that the connection of the metal busbars is unqualified, if so, collecting a resistance value Rx between the two metal busbars, comparing the resistance value Rx with a preset standard value R ', and judging whether the connection of the metal busbars is qualified or not according to a resistance value comparison result. According to the invention, the connection state of the metal busbar can be judged, and the accuracy of online detection is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of battery detection, and particularly to an online detection method and device for the connection condition of metal busbars in a battery pack. Background Art

[0002] As the main power source of new energy vehicles, the reliability of the connection of electrical components inside a battery pack is crucial for vehicle safety. As the main conductive component inside the battery pack, if the metal busbars do not achieve effective bonding, a large amount of heat will be generated at the bonding position during use, which will burn out the metal busbars, cause the external output of the battery pack to be disconnected, and then the battery pack stops supplying power and the electric vehicle stops running.

[0003] The metal busbars inside the battery pack are generally fastened with bolts. The common inspection method is to detect the torque of the bolts and confirm the torque of the fastening bolts thereon. However, if the threads of the fixing bolts are abnormal and the bolts are stuck during the tightening process, even if the torque value is reached, the actual bolts do not really press the metal busbars; or due to the poor flatness of the metal busbars themselves, there will be gaps after installation, so that the contact surfaces of the two metal busbars cannot be closely bonded, resulting in a large amount of heat generation during use and burning out the metal busbars. This kind of situation will be missed in production, that is, unqualified products are shipped as qualified products. Therefore, the existing inspection method of bolt torque cannot effectively reflect the true bonding state of the metal busbars, resulting in the risk of misjudgment in the obtained test results. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies and defects of the prior art, and provide an online detection method and device for the connection condition of metal busbars in a battery pack. The present invention can directly detect the bonding situation of the battery metal busbars online, improving the efficiency and accuracy of detecting the battery metal busbars.

[0005] One object of the present invention is to provide an online detection method for the connection condition of metal busbars in a battery pack, including:

[0006] During the operation of fastening the metal busbars with bolts, when it is monitored that the bolt torque reaches the preset torque value, measure the distance values L1 and L2 from a preset position to the upper surfaces of the two metal busbars, and calculate the gap value L' between the two metal busbars based on the distance values L1 and L2;

[0007] Judge whether the gap value L' is within the preset standard value range L'min~L'max. If not, it is determined that the connection of the metal busbars is unqualified. If so, collect the resistance value Rx between the two metal busbars, compare the resistance value Rx with the preset standard value R', and judge whether the connection of the metal busbars is qualified according to the result of the resistance comparison.

[0008] Wherein, the gap value L' is calculated by the following formula:

[0009] L’ = L1 - L2 - L, where L represents the center value / average value of the thickness of the metal busbar.

[0010] Among them, the distance values L1 and L2 from the preset position to the upper surfaces of the two metal busbars are measured by a laser ranging device. The laser ranging device includes two laser rangefinders, which are respectively used to measure the distance values L1 and L2.

[0011] Among them, the resistance value Rx between the two metal busbars is collected by metal probes. There are two metal probes, which are respectively pressed against the two metal busbars for measurement.

[0012] Among them, the preset standard value range L’min~L’max is obtained based on the distribution range of multiple clearance values L’ obtained after multiple bolt tightening experiments on the metal busbars of the same batch.

[0013] Among them, the preset standard value R’ is the maximum value among the multiple resistance values obtained after multiple bolt tightening experiments on the metal busbars of the same batch, and is the upper limit value of the resistance value.

[0014] Another object of the present invention is to provide an on-line detection device for the connection status of the metal busbar of a battery pack, which is used to implement the on-line detection method for the connection status of the metal busbar of the battery pack. It is characterized by including:

[0015] A ranging device, the ranging device includes two laser rangefinders, which are used to detect the distance values L1 and L2 from the preset position to the upper surfaces of the two metal busbars during the operation of bolt-tightening the metal busbars;

[0016] Metal probes, there are two metal probes, which are used to collect the resistance value Rx between the two metal busbars during the operation of bolt-tightening the metal busbars;

[0017] A torque system, the torque system is connected to the torque gun sleeve. The torque gun sleeve is used to bolt-tighten the metal busbars. The torque system is used to monitor whether the bolt torque reaches the preset torque value;

[0018] A control unit, which is used to calculate the clearance value L’ of the two metal busbars based on the distance values L1 and L2, judge whether the clearance value L’ is within the preset standard value range L’min~L’max, and compare the resistance value Rx with the preset standard value R’ during the operation of bolt-tightening the metal busbars, and output a judgment result on whether the connection of the metal busbar is qualified.

[0019] Among them, the control unit is connected to the torque system, the laser rangefinder and the metal probe 86 through a signal acquisition wire harness.

[0020] Among them, the control unit includes a PLC control unit.

[0021] Among them, the two laser rangefinders are symmetrically arranged, and the two metal probes are symmetrically arranged.

[0022] On the premise that the torque of the connecting bolts of the metal busbar of the present invention meets the target torque, the resistance value between the two metal busbars is measured, and the height difference between the two metal busbars is collected and analyzed. By directly comprehensively comparing and analyzing the torque value of the connecting bolts, the size difference between the two metal busbars, and the resistance value between the two metal busbars, the connection state of the metal busbar is determined, which improves the accuracy of on-line detection. Description of the Drawings

[0023] Figure 1 is a flowchart of the on-line detection method for the connection status of the metal busbar of the battery pack of the present invention.

[0024] Figure 2 is a schematic diagram of the detection and use of the on-line detection device for the connection status of the metal busbar of the battery pack of the present invention.

[0025] Figure 3 is a schematic diagram of the on-line detection device for the connection status of the metal busbar of the battery pack of the present invention.

[0026] Figure 4 is a partial schematic diagram of the on-line detection device for the connection status of the metal busbar of the battery pack of the present invention.

[0027] Figure 5 is a schematic diagram of the detection principle of the on-line detection device for the connection status of the metal busbar of the battery pack of the present invention.

[0028] Description of the Reference Numerals:

[0029] 1 - Workbench, 2 - Battery pack box body, 3 - Support column, 4 - Series row bottom plate, 5 - 1# Metal busbar, 6 - 2# Metal busbar, 7 - Fastening bolt, 8 - Detection device.

[0030] 81 - PLC control unit, 82 - Signal transmission wire harness, 83 - Torque system, 84 - Device fixing block, 85 - Torque gun sleeve, 86 - Metal probe, 87 - Laser rangefinder;

[0031] 841 - Insulating pad, 842 - Metal probe pad, 843 - Metal probe clamping plate, 844 - Metal probe clamping plate;

[0032] 861 - Upper end of metal probe, 862 - Metal probe spring, 863 - Metal probe telescopic rod, 864 - Metal probe signal acquisition point;

[0033] 871 - Laser rangefinder signal acquisition point. Detailed implementation manner

[0034] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0035] An object of the present invention is to provide an on - line detection method for the connection status of a battery pack metal busbar. As shown in Figure 1 , it includes: during the operation of tightening the metal busbar with bolts, when it is monitored that the bolt torque reaches the preset torque value, measure the distance values L1 and L2 from the preset position to the upper surfaces of the two metal busbars, and calculate the clearance value L' between the two metal busbars based on the distance values L1 and L2; determine whether the clearance value L' is within the preset standard value range L'min ~ L'max. If not, it is determined that the connection of the metal busbar is unqualified. If so, collect the resistance value Rx between the two metal busbars, compare the resistance value Rx with the preset standard value R', and determine whether the connection of the metal busbar is qualified according to the resistance value comparison result.

[0036] Among them, the clearance value L' is calculated by the following formula:

[0037] L' = L1 - L2 - L, where L represents the center value / average value of the thickness of the metal busbar.

[0038] In a preferred implementation manner, the distance values L1 and L2 from the preset position to the upper surfaces of the two metal busbars are measured by a laser ranging device. The laser ranging device includes two laser rangefinders, which are respectively used to measure the distance values L1 and L2.

[0039] In a preferred implementation manner, the resistance value Rx between the two metal busbars is collected by metal probes. There are two metal probes, which are respectively pressed against the two metal busbars for measurement.

[0040] Among them, the preset standard value range L'min ~ L'max is obtained based on the distribution range of multiple clearance values L' obtained after multiple bolt - tightening experiments on the metal busbars of the same batch. Specifically, the metal busbars of the same batch can be used for detection experiments to obtain n clearance values L', and then the standard upper and lower limits L'min ~ L'max are determined according to the distribution range of the n L'.

[0041] Among them, the preset standard value R' is the maximum value among the multiple resistance values obtained after multiple bolt - tightening experiments on the metal busbars of the same batch, which is the upper limit value of the resistance value. Specifically, n experiments are carried out using the metal busbars of the same batch to obtain the maximum value R' of the resistance value between the two metal busbars, which is used as the standard upper limit, that is, the preset standard value.

[0042] Another object of the present invention is to provide an on-line detection device for the connection status of the battery pack metal busbar, which is used to implement the on-line detection method for the connection status of the battery pack metal busbar, as Figures 2 - 5 shown, including:

[0043] A ranging device, the ranging device includes two laser rangefinders 87, which are used to detect the distance values L1 and L2 from a preset position to the upper surfaces of two metal busbars during the operation of bolting and fastening the metal busbars;

[0044] Metal probes 86, there are two metal probes, which are used to collect the resistance value Rx between two metal busbars during the operation of bolting and fastening the metal busbars;

[0045] A torque system 83, the torque system is connected to a torque gun sleeve 85, the torque gun sleeve 85, which is used to set a preset torque value during the operation of bolting and fastening the metal busbars, and the torque system 83 is used to monitor whether the bolt torque reaches the preset torque value;

[0046] A control unit, which is used to calculate the clearance value L' between two metal busbars based on the distance values L1 and L2, determine whether the clearance value L' is within the preset standard value range L'min to L'max, and compare the resistance value Rx with the preset standard value R' during the operation of bolting and fastening the metal busbars, and output a judgment result on whether the connection of the metal busbar is qualified.

[0047] In the embodiment of the present application, during specific measurement, when it is monitored in real time online that the torque value is reached, the torque system will give a signal to the control unit and then automatically start the rangefinder to start measurement; after the ranging is completed, the control unit controls the calculation of the clearance value L' and automatically decides whether to measure the resistance value, and then judges whether the connection of the metal busbar is qualified according to the measured resistance value.

[0048] In a preferred embodiment, the control unit is connected to the torque system 83, the laser rangefinder 87 and the metal probe 86 through a signal acquisition wire harness 82, and the torque system 83 can set the torque value.

[0049] In a preferred embodiment, the control unit includes a PLC control unit 81.

[0050] In a preferred embodiment, the two laser rangefinders 87 are symmetrically arranged, and the two metal probes 86 are symmetrically arranged.

[0051] Specifically, the on-line detection device for the connection status of the battery pack metal busbar further includes a device fixing block 84, an insulating backing plate 841, a metal probe backing plate 842, a first metal probe clamping plate 843, a second metal probe clamping plate 844, a torque gun sleeve 85, a metal probe upper end 861, a metal probe spring 862, a metal probe telescopic rod 863, a metal probe signal acquisition point 864, and a laser rangefinder signal acquisition point 871.

[0052] Among them, the metal probe 86 is composed of a metal probe upper end 861, a metal probe spring 862, a metal probe telescopic rod 863, and a metal probe signal acquisition point 864. There is a metal probe spring 862 in the cavity of the metal probe upper end 861. The lower end of the metal probe spring 862 is connected to the metal probe telescopic rod 863. The metal probe signal acquisition point 864 at the end of the probe is connected to the control unit through a signal acquisition wire harness 82.

[0053] Among them, the metal probe 86 is installed on the side of the device fixing block 84 by a first metal probe clamping plate 843 and a second metal probe clamping plate 844 arranged separately up and down. There is an insulating backing plate 841 on the side of the device fixing block 84, and there is a metal probe backing plate 842 between the first metal probe clamping plate 843 and the insulating backing plate 841.

[0054] Among them, the laser rangefinder signal acquisition point 871 of the laser rangefinder is arranged on the side of the device fixing block 84.

[0055] Among them, the lower part of the torque system 83 is connected to the torque gun sleeve 85, and the torque gun sleeve 85 is used for tightening the fastening bolts.

[0056] When operating the on-line detection device for the connection status of the battery pack metal busbar of the present invention, the battery pack box body 2 can be placed on the workbench 1 for operation. There is a series connection row bottom plate 4 at the upper end of the battery pack box body, and there are support columns 3 on the series connection row bottom plate. Align the fastening bolt holes of the 1# metal busbar 5 and the 2# metal busbar 6 to be connected with the support columns 3, place them on the upper ends of the support columns 3, pre-tighten the fastening bolts 7 to the upper ends of the support columns 3, and then use the torque gun sleeve 85 for tightening operation to tighten the fastening bolts 7 on the support columns 3, so as to install the two metal busbars on the support columns 3 in the battery box body, as Figure 2 shown.

[0057] In this application, the two laser rangefinders are independent. Before use, they are calibrated against the same reference plane, and the torque target value A is set through the torque system 83, and then the tightening operation of the fastening bolts 7 can be started.

[0058] The detection steps of the on-line detection device for the connection status of the battery pack busbar of the present application are specifically as follows: Set the torque target value A of the torque system through the torque system 83, and at the same time press two metal probes against the upper surfaces of two metal busbars respectively; then use the torque gun sleeve 85 to tighten the fastening bolts of the metal busbar to start the fastening operation. When the torque reaches the torque target value A, the two laser rangefinders respectively measure the distance from the preset position to the upper surface of the metal busbar, and record the values L1 and L2. Confirm the connection status of the two rows, confirm that the fastening is effective, and record the gap L' of the metal busbar = L1 - L2 - L, where L represents the center value of the busbar thickness of the metal busbar, that is, the average busbar thickness value of the metal busbar; compare the obtained gap Lx of the metal busbar to be measured with L', if Lx > L'max or Lx < L'min, it is determined to be unqualified, otherwise it is determined to be qualified. In the case where the actual gap Lx falls within the range of L'min to L'max, collect the resistance value Rx between the two metal probes, and compare it with the standard R'. If Rx ≤ R', it is determined that the final product is qualified, otherwise it is determined that the final product is unqualified.

[0059] During the tightening operation, it is possible that the bolt gets stuck, causing the metal busbar not to be tightly pressed, or the thickness difference of the metal busbars is large, resulting in the situation of unqualified products being regarded as qualified products when the test distance is obtained. When the torque reaches the set torque, when the two metal busbars are not in good contact, their resistance value is large, and when they are in close contact, the resistance value is small. Therefore, in the present application, on the premise that the gap Lx is qualified, the resistance values between the two metal busbars collected by the two metal probes on both sides of the test are used for determination, so as to further increase the accuracy of the qualification determination.

[0060] On the premise that the torque value of the connecting bolt meets the threshold, the present invention can truly reflect the connection gap state of the two metal busbars by measuring the resistance value between the metal busbars and the distance dimension of the metal busbar, and comparing the distance difference and the resistance value. Using the distance difference range and resistance value standard obtained from the previous experiments as the determination conditions, the effectiveness and accuracy of the on-line determination are finally realized.

[0061] The technology of the present invention can effectively and accurately detect the fastening state of the two metal busbars, and reduce the risk of defective products flowing out due to only detecting the bolt torque.

[0062] The above shows and describes the basic principles, main features and advantages of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or basic features of the present invention.

[0063] Therefore, in any aspect, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Thus, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present invention.

[0064] In addition, it should be understood that although this specification is described in terms of embodiments, not every embodiment contains only one independent technical solution. This narrative style of the specification is only for clarity. Those skilled in the art should view the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An online detection method for the connection status of the metal busbar of a battery pack, characterized in that, Including: During the operation of bolt-tightening the metal busbar, when it is monitored that the bolt torque reaches the preset torque value, measure the distance values L1 and L2 from the preset position to the upper surfaces of the two metal busbars, and calculate the clearance value L' between the two metal busbars based on the distance values L1 and L2; Judge whether the clearance value L' is within the preset standard value range L'min~L'max. If not, it is determined that the connection of the metal busbar is unqualified. If so, collect the resistance value Rx between the two metal busbars, compare the resistance value Rx with the preset standard value R', and judge whether the connection of the metal busbar is qualified according to the resistance comparison result.

2. The online detection method for the connection status of the battery pack metal busbar according to claim 1, characterized in that, The clearance value L' is calculated by the following formula: L' = L1 - L2 - L, where L represents the center value / average value of the busbar thickness of the metal busbar.

3. The online detection method for the connection status of the battery pack metal busbar according to claim 1, characterized in that Measure the distance values L1 and L2 from the preset position to the upper surfaces of the two metal busbars through a laser ranging device. The laser ranging device includes two laser rangefinders, which are respectively used to measure the distance values L1 and L2.

4. The online detection method for the connection status of the battery pack metal busbar according to claim 1, characterized in that, Collect the resistance value Rx between the two metal busbars through metal probes. There are two metal probes, which are respectively pressed against the two metal busbars for measurement.

5. The online detection method for the connection status of the battery pack metal busbar according to claim 1, wherein The preset standard value range L'min~L'max is obtained based on the distribution range of multiple clearance values L' obtained after multiple bolt-tightening experiments on the metal busbars of the same batch.

6. The online detection method for the connection status of the metal busbar of the battery pack according to claim 1, wherein The preset standard value R' is the maximum value among multiple resistance values obtained after multiple bolt-tightening experiments on the metal busbars of the same batch, and is the upper limit value of the resistance value.

7. Online detection device for the connection status of the metal busbar of the battery pack, characterized in that, For implementing the on-line detection method for the connection status of the metal busbar of the battery pack according to any one of claims 1-6, it is characterized by including: A ranging device, the ranging device includes two laser rangefinders, and is used to detect the distance values L1 and L2 from the preset position to the upper surfaces of the two metal busbars during the operation of bolt-tightening the metal busbar; Metal probes, there are two metal probes, and are used to collect the resistance value Rx between the two metal busbars during the operation of bolt-tightening the metal busbar; A torque system, the torque system is connected to the torque gun sleeve. The torque gun sleeve is used during the operation of bolt-tightening the metal busbar, and the torque system is used to monitor whether the bolt torque reaches the preset torque value; A control unit, which is used during the operation of bolt-tightening the metal busbar to calculate the clearance value L' between the two metal busbars based on the distance values L1 and L2, judge whether the clearance value L' is within the preset standard value range L'min~L'max, and compare the resistance value Rx with the preset standard value R', and output the judgment result of whether the connection of the metal busbar is qualified.

8. The on-line detection device for the connection status of the battery pack metal busbar according to claim 7, characterized in that The control unit is connected to the torque system, the laser rangefinder and the metal probe 86 through a signal acquisition wire harness.

9. The online detection device for the connection status of the battery pack metal busbar according to claim 7, characterized in that, The control unit includes a PLC control unit.

10. The online detection device for the connection status of the battery pack metal busbar according to claim 7, wherein, The two laser rangefinders are symmetrically arranged, and the two metal probes are symmetrically arranged.

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