CN120028391A

CN120028391A - Secondary battery cell tab tear detection method, device, battery, system and equipment

Info

Publication number: CN120028391A
Application number: CN202510517917.7A
Authority: CN
Inventors: 陈灿; 马玉俊
Original assignee: Zhejiang Jingke Energy Storage Co ltd
Current assignee: Zhejiang Jingke Energy Storage Co ltd
Priority date: 2025-04-23
Filing date: 2025-04-23
Publication date: 2025-05-23
Anticipated expiration: 2045-04-23
Also published as: CN120028391B

Abstract

The present application relates to a secondary battery cell tab tear detection method, device, battery, system and equipment. The secondary battery cell tab tear detection device is applied to a contact-connected secondary battery cell to be detected, wherein the secondary battery cell to be detected is fixed with tabs, and a double-layer capacitor is formed between the positive and negative electrodes of the secondary battery cell to be detected in the electrolyte; the method comprises: after the secondary battery cell to be detected is fully immersed in the electrolyte, a first current test signal is applied to the secondary battery cell to be detected within a first target frequency interval, and the double-layer capacitor is in an open circuit state within the first target frequency interval; according to the first current test signal, the test resistance value of the secondary battery cell to be detected is tested; according to the relationship between the actual resistance value calibrated during the actual test process and the preset resistance value, the secondary battery cell to be detected is detected for tab tearing. The use of this method improves the detection accuracy of tab tear detection for secondary batteries.

Description

Method, device, battery, system and equipment for detecting tearing of secondary battery cell tab

Technical Field

The application relates to the technical field of battery cell performance test, in particular to a secondary battery cell tab tearing detection method and device, a secondary battery, an energy storage system and electric equipment.

Background

In the process of carrying out ultrasonic welding on the multilayer current collector, the secondary battery cell can cause the phenomenon of tearing of the electrode lug due to the influence of welding stress in the welding process due to the reasons of folding, wrinkling, dislocation and the like in the multilayer current collector, and the phenomenon of poor phenomena such as burrs, abnormal protrusions, breakage and the like which are easy to occur in the subsequent assembly process can be caused by tearing of the electrode lug, so that the resistance value of the secondary battery cell is influenced, and therefore, the detection of tearing of the electrode lug of the secondary battery cell is necessary.

At present, in the process of detecting the tearing of the secondary battery cell tab, a DCIR (Direct Current INTERNAL RESISTANCE ) testing device or an ACIR (ALTERNATING CURRENT INTERNAL RESISTANCE, alternating Current internal resistance) testing instrument is generally used for measuring the resistance value of the secondary battery cell, so that the poor tearing of the secondary battery cell tab is identified by using the resistance value, but the total impedance measured by the existing measuring mode cannot reflect the actual resistance value of the secondary battery cell in a specific state, so that the Current detection result of detecting the tearing of the tab of the secondary battery cell has the problem of low accuracy.

Disclosure of Invention

Based on the above, it is necessary to provide a secondary battery tab tearing detection method, device, secondary battery, energy storage system and electric equipment for improving the detection accuracy of tab tearing detection on the secondary battery.

In a first aspect, the application provides a method for detecting tearing of a secondary battery cell tab, which is applied to a device for detecting tearing of a secondary battery cell tab, wherein the device for detecting tearing of the secondary battery cell tab is in contact connection with a secondary battery cell to be detected, the secondary battery cell to be detected is fixed with the tab, the secondary battery cell to be detected comprises an anode and a cathode, an electric double layer capacitor is formed between the anode and the cathode in an immersed electrolyte, and the method comprises the following steps:

After the secondary battery core to be detected is fully soaked in the electrolyte, a first current test signal is applied to the secondary battery core to be detected in a first target frequency interval, wherein the electric double layer capacitor is in an open circuit state in the first target frequency interval;

Testing the test resistance value of the secondary battery cell to be detected according to the first current test signal;

And determining an actual resistance value obtained by calibrating the test resistance value in an actual test process, and carrying out tab tearing detection on the secondary battery cell to be detected according to the magnitude relation between the actual resistance value and a preset resistance value.

The application also provides a secondary battery cell tab tearing detection device, which comprises a resistance measurement device and an upper computer, wherein the resistance measurement device is in contact connection with a secondary battery cell to be detected, the resistance measurement device is in communication connection with the upper computer, the upper computer comprises an application module and a detection module, the secondary battery cell to be detected is fixedly provided with a tab, the secondary battery cell to be detected comprises a positive electrode and a negative electrode, an electric double layer capacitor is formed between the positive electrode and the negative electrode in immersed electrolyte,

The application module is used for applying a first current test signal to the secondary battery cell to be detected in a first target frequency interval after the secondary battery cell to be detected is fully immersed in the electrolyte, wherein the electric double layer capacitor is in an open circuit state in the first target frequency interval;

The resistance measuring device is used for testing the test resistance value of the secondary battery cell to be detected according to the first current test signal;

the detection module is used for determining an actual resistance value obtained by calibrating the test resistance value in an actual test process, and carrying out tab tearing detection on the secondary battery cell to be detected according to the magnitude relation between the actual resistance value and a preset resistance value.

In a third aspect, the application further provides a secondary battery, the secondary battery comprises a secondary battery core, and the secondary battery core has no electrode tab tearing, wherein the detection result of the secondary battery core has no electrode tab tearing is detected by the secondary battery core electrode tab tearing detection method.

In a fourth aspect, the present application also provides an energy storage system comprising a secondary battery as above.

In a fifth aspect, the present application also provides a powered device comprising an energy storage system as above.

In view of deployment of the secondary battery tab tearing detection device, the secondary battery, the energy storage system and the electric equipment, the secondary battery tab tearing detection device is in contact connection with the secondary battery to be detected, the secondary battery to be detected is provided with a positive electrode and a negative electrode, an electric double layer capacitor is formed between the positive electrode and the negative electrode of the secondary battery to be detected in the immersed electrolyte, after the secondary battery to be detected is fully immersed in the electrolyte, electrochemical reaction between the positive electrode and the negative electrode of the secondary battery to be detected is stable, the electrical performance of the secondary battery can be objectively reflected, and when a first current test signal is applied to the secondary battery to be detected by the secondary battery tab device in a first target frequency range, the electric double layer capacitor is in an open circuit state, so that impedance parts of the electric double layer capacitor in a circuit are not ignored, therefore, the test resistance value of the secondary battery cell to be detected can be obtained by capturing the resistance change condition of the secondary battery cell under the polarization effect in real time, and finally the secondary battery cell to be detected is subjected to the tab tearing detection according to the magnitude relation between the actual resistance value obtained by calibrating the test resistance value in the actual test process and the preset resistance value, and the actual resistance value obtained by calibrating the secondary battery cell tab tearing detection device is attached to the actual test process, so that the resistance change condition of the secondary battery cell under the polarization effect can be detected, the actual resistance value can reflect the actual resistance condition of the secondary battery cell under the specific state, the detection basis of the actual resistance value obtained by detection as the tab tearing detection of the secondary battery cell to be detected is reliable, therefore, the internal resistance value component of the secondary battery cell which is faced to rest in the electrolyte is complex, and the DCIR device is a total impedance detection finished by utilizing the charge and discharge characteristics of the secondary battery cell, and under the condition that the polarization effect in the secondary battery cell can change along with the change of the charge and discharge process and the like, the technical defect that the actual resistance value of the secondary battery cell in a specific state cannot be reflected by the total impedance measured by the DCIR device can be overcome by adopting the secondary battery cell tab tearing detection device, so that the detection accuracy of tab tearing detection of the secondary battery cell is improved.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the related art, the drawings that are required to be used in the embodiments or the related technical descriptions will be briefly described, and it is apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to the drawings without inventive effort for those skilled in the art.

FIG. 1 is a schematic flow chart of a method for detecting tearing of a secondary battery tab in an embodiment;

FIG. 2 is a first schematic diagram of a partial process in a battery manufacturing process of a secondary cell tab tear detection method according to one embodiment;

Fig. 3 is a schematic diagram of a test circuit of a secondary battery cell to be detected when an electric double layer capacitor of the secondary battery cell tab tearing detection method is in different states in an embodiment;

FIG. 4 is a second schematic diagram of a partial process in the battery manufacturing process of the secondary cell tab tear detection method according to one embodiment;

FIG. 5 is a third schematic diagram of a partial process in a battery manufacturing process of a secondary cell tab tear detection method according to one embodiment;

fig. 6 is a flow chart of a method for detecting tearing of a secondary battery tab according to another embodiment;

FIG. 7 is a fourth schematic diagram of a partial process in a battery manufacturing process of a secondary cell tab tear detection method according to another embodiment;

Fig. 8 is a schematic diagram of a partial module of a secondary battery tab tear detection device according to another embodiment.

Detailed Description

The present application will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present application more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application.

Firstly, the secondary battery core is a chargeable battery core capable of repeatedly performing charge and discharge cycles, and has numerous characteristics of repeated charge and discharge, high energy density, energy conservation, environmental protection and the like, so that the secondary battery core is widely applied in numerous industries, and in the lithium ion battery industry, a welding tearing phenomenon caused by poor reasons such as folding, wrinkling and dislocation exists in a multi-layer current collector due to welding stress existing in the ultrasonic welding process of the lithium ion battery, so that burrs, abnormal protrusions, fractures and the like are easily generated in the subsequent assembly process, and finally the ohmic resistance value of the lithium ion battery is influenced, wherein the ohmic resistance value mainly refers to the resistance value formed by electrode materials, electrolyte, diaphragm resistance and contact resistance of other parts, and at present, when the welding tearing phenomenon of the lithium ion battery is detected, the secondary battery core internal resistance value obtained through testing is generally used as a detection basis, namely, when the secondary battery internal resistance value obtained through testing is too large, the lithium ion battery is judged to have tab tearing.

Secondly, it can be understood that the internal resistance value of the secondary battery cell can be measured by the DCIR device or the ACIR tester, compared with the DCIR device, the total impedance measured by the ACIR tester has higher accuracy and stability, and in general, the ACIR tester measures the impedance of the secondary battery cell by using a test frequency of 1kHz and an amplitude of 5mV, but because the internal resistance value of the secondary battery cell which is placed in the electrolyte is complex, the DCIR device or the ACIR tester can detect the total impedance by utilizing the characteristics of the secondary battery cell, and the polarization effect in the secondary battery cell changes along with the change of the charging and discharging process, so that the total impedance measured by the DCIR device or the ACIR tester cannot reflect the actual resistance value of the secondary battery cell in a specific state, wherein the total impedance measured by the DCIR device or the ACIR tester obviously cannot include the polarization resistance formed by the secondary battery cell due to electrochemical reaction, so that the detected secondary battery cell internal resistance value is more complicated than the component of the secondary battery cell, and the secondary battery cell is required to be torn when the actual battery cell is more than the actual battery cell, and the secondary battery cell is more accurate when the secondary battery cell is torn, and the secondary battery cell is required to be torn, and the secondary battery cell is more accurate when the secondary battery cell is required to be torn.

In an embodiment, as shown in fig. 1, a method for detecting tearing of a secondary battery tab is provided, where the method is applied to a secondary battery tab tearing detection device, and the secondary battery tab tearing detection device is in contact connection with a secondary battery to be detected, and the contact connection mode may specifically be that the secondary battery tab tearing detection device is electrically connected with the secondary battery to be detected through a test probe or a test clip, where the secondary battery tab tearing detection device includes a resistance measurement device and an upper computer, where the resistance measurement device is in communication connection with the upper computer, the resistance measurement device is used to measure a test resistance value of the battery to be detected according to a first current test signal applied by the upper computer, the upper computer includes, but is not limited to, a notebook computer, a smart phone, a tablet computer, and the upper computer includes an application module and a detection module, where the application module is used to apply a first current test signal to the secondary battery to be detected in a first target frequency interval, and the detection module is used to determine an actual resistance value obtained by calibration of the test resistance value in an actual test process, and perform a tearing relationship between the actual resistance value and the actual resistance value to be detected and the actual resistance value.

In the process of carrying out the tearing detection on the secondary battery cell, a certain detection condition needs to be met among the electrode tab, the secondary battery cell to be detected, the resistance measuring device and the upper computer, the electrode tab needs to be fixed on the secondary battery cell to be detected first, the secondary battery cell to be detected comprises an anode and a cathode, specifically, the electrode tab can be welded on the anode and the cathode of the secondary battery cell to be detected so as to realize the reliable connection between the battery cell to be detected and an external circuit, the secondary battery cell to be detected is immersed in electrolyte, an electric double layer capacitor is formed between the anode and the cathode of the secondary battery cell to be detected in the immersed electrolyte, wherein the electric double layer capacitor is formed on the basis of an electric double layer theory, when the anode and the cathode of the secondary battery cell to be detected are immersed in the electrolyte, a layer of compact charge layer is formed on the surface of the electrode due to the interaction between the surface of the electrode and the electrolyte, the charge layer is composed of charges on the surface of the electrode and opposite ions in the electrolyte, and is tightly arranged through coulomb force, so that an electric double layer capacitor is formed, meanwhile, the secondary battery core to be detected needs to be fully soaked in the electrolyte, so that the secondary battery core to be detected can fully perform electrochemical reaction in the electrolyte, the polarization resistance value formed through the electrochemical reaction accurately reflects the polarization resistance condition of the secondary battery core to be detected, a first current test signal is applied to the secondary battery core to be detected in a first target frequency interval by a host computer control resistance measuring device, the electric double layer capacitor is in an open circuit state in the first target frequency interval, and then the secondary battery core tab tearing detecting device is used for testing the test resistance value of the secondary battery core to be detected based on the first current test signal, therefore, the test resistance value obtained by the test is composed of an ohmic resistance value and a polarization resistance value, the practical application scene can be attached, the practical resistance value obtained by calibrating the test resistance value in the practical test process is determined through the upper computer, and the tab tearing detection is carried out on the secondary battery cell to be detected according to the magnitude relation between the practical resistance value and the preset resistance value.

On the one hand, the secondary battery cell tab tearing detection device can detect the resistance change condition of the secondary battery cell to be detected under the polarization effect, so that the detected test resistance value can accurately reflect the actual resistance condition of the secondary battery cell under the specific state, on the other hand, the actual resistance value is obtained by calibrating the test resistance value for fitting the actual test process, so that the actual resistance value can completely and objectively reflect the actual resistance condition of the secondary battery cell to be detected under the specific state, and finally the detected actual resistance value is reliable as the detection basis for tab tearing detection of the secondary battery cell to be detected, so that the detection accuracy of tab tearing detection of the secondary battery cell is improved. In this embodiment, the method includes the following steps 202 to 206. Wherein:

Step 202, after the secondary battery cell to be detected is fully immersed in the electrolyte, a first current test signal is applied to the secondary battery cell to be detected in a first target frequency interval, wherein the electric double layer capacitor is in an open circuit state in the first target frequency interval.

It should be noted that, the positive electrode and the negative electrode of the secondary battery core to be detected are both fixed with tabs, the tearing detection of the tab of the secondary battery core to be detected may specifically be the tearing detection of the first tab fixed on the positive electrode of the secondary battery core to be detected, the tearing detection of the second tab fixed on the negative electrode of the secondary battery core to be detected, or the tearing detection of the first tab and the second tab, it may be understood that the secondary battery core to be detected refers to the secondary battery core waiting for the tearing detection of the tab, the positive electrode and the negative electrode of the secondary battery core to be detected may be a single-layer conductive sheet, or may be a multi-layer current collector formed by multiple layers of conductive sheets, the conductive material may specifically be aluminum or copper, the electrolyte that wets the secondary battery core to be detected may specifically be ethylene carbonate, dimethyl carbonate, methyl carbonate or lithium hexafluorophosphate, etc., and in one embodiment, the positive electrode and the negative electrode of the secondary battery core to be detected are both made of a layer of aluminum foil.

It should be noted that, in the process of performing tab tearing detection on the secondary battery core to be detected, a specific detection procedure is set to ensure quality control of the overall battery preparation process, for example, in an implementation manner, referring to fig. 2, fig. 2 is a first schematic diagram of a local process in the battery preparation process, where first, the secondary battery core is subjected to one injection and then to a high-temperature infiltration and formation process, after the formation process is completed, electrolyte wiping and high-temperature aging are sequentially performed, further, the secondary battery core sequentially flows through the secondary injection, seal nail welding, helium detection, separation capacity, first normal-temperature standing, first measuring open-circuit voltage (Open Circuit Voltage, OCV), second normal-temperature standing, second measuring open-circuit voltage, state of Charge (SOC), and third normal-temperature standing, and then after the third normal-temperature standing is completed, a direct-current internal resistance test procedure is set, that is, the internal resistance value of the secondary battery core is measured by the direct-current internal resistance test device, after the secondary battery core is subjected to direct-current resistance test, the electrical core is subjected to three-time internal resistance value measurement, and the electrical core is subjected to direct-current resistance test, and the second normal-temperature voltage measurement is performed as an internal resistance value, and the second normal-temperature measurement is performed, and the open-circuit value is automatically measured, and the appearance value is automatically measured as an open-circuit value, and is automatically measured at the second internal resistance value, and is subjected to a second normal-temperature test, and a normal-temperature measurement time, and a normal-temperature measurement is subjected to an internal resistance test, the internal resistance value of the secondary battery cell to be detected can be calculated according to the phase difference and the amplitude of the measured current and the measured voltage by applying the sine waveform exciting current to the secondary battery cell to be detected, and the internal resistance value of the secondary battery cell to be detected is used as a detection basis to detect the tearing condition of the electrode lug of the secondary battery cell to be detected.

It can be understood that in the conventional technology, there is an obvious defect in the process of detecting the tearing of the electrode lug of the secondary battery core to be detected, the DCIR device or the ACIR tester is a total impedance detection completed by utilizing the charge-discharge characteristics of the secondary battery core, only the ohmic resistance value of the secondary battery core to be detected can be detected, but the internal resistance value component of the secondary battery core to be detected immersed in the electrolyte is complex, besides the ohmic resistance value, the polarized resistance value formed under the polarized effect is also formed, and as the polarized effect in the secondary battery core to be detected changes along with the change of the DCIR device or the ACIR tester in the charge-discharge process of testing the impedance condition of the secondary battery core, the polarized resistance value of the secondary battery core to be detected cannot be accurately captured, so that the total impedance measured by the DCIR device or the ACIR tester cannot reflect the actual resistance value of the secondary battery core in a specific state, and finally the measured resistance value of the DCIR device or the ACIR tester is unreliable as the detection basis.

It should be noted that, the secondary battery core to be detected is fully immersed in the electrolyte, which is a precondition for performing the tab tearing detection of the secondary battery core to be detected, which can ensure that the positive electrode and the negative electrode of the secondary battery core to be detected are fully reacted in the immersed electrolyte, specifically, a local process in the conventional battery preparation process can be used, for example, after the secondary battery completes the process of standing at the third normal temperature, the secondary battery can be considered to be fully immersed in the electrolyte, and the local process in the conventional battery preparation process can be improved, for example, when the secondary battery performs the standing at the third normal temperature, if the standing time reaches the preset time length, the secondary battery is determined to be fully immersed in the electrolyte, and it can be understood that the preset time length is greater than the default standing time length set for the standing at the third normal temperature in the conventional process.

It should be noted that, the secondary battery core to be detected may be connected to the internal resistance measurement device of the secondary battery tab tear detection device in a contact manner, after the secondary battery core to be detected is fully immersed in the electrolyte, the upper computer may trigger the internal resistance measurement device to apply a first current test signal to the secondary battery core to be detected in a first target frequency interval through the application module, where the first current test signal is used to test a test resistance value of the secondary battery core to be detected, the first target frequency interval refers to a frequency interval in which the electric double layer capacitor is in an open-circuit state, the internal resistance measurement device may be a conventional ACIR tester, that is, an ac internal resistance tester, and it may be understood that, due to a change in impedance characteristics of the electric double layer capacitor along with frequencies, the electric double layer capacitor may exhibit different states in the current test signals in the different frequency intervals, specifically, under the high-frequency current test signal, the capacitive resistance of the electric double layer capacitor may be significantly reduced, after the capacitive resistance is reduced to a certain extent, and under the low-frequency current test signal, the capacitive double layer capacitor may be in a state after the capacitive double layer capacitor is increased to a certain extent.

Referring to fig. 3, fig. 3 is a schematic diagram of a test circuit of a secondary battery cell to be detected when the electric double layer capacitor is in different states, wherein (a) is a schematic diagram of a first test circuit of the secondary battery cell to be detected when the electric double layer capacitor is in a short circuit state, V1 is a voltage of the first test circuit,For the polarization resistance component in the first test circuit,For the electrolyte interface resistance component in the first test circuit,Is an ohmic resistance component in the first test circuit, (b) is a schematic diagram of a second test circuit of the secondary battery cell to be detected when the electric double layer capacitor is in an open state, V2 is a voltage of the second test circuit,For the polarization resistance component in the second test circuit,For the electrolyte interface resistance component in the second test circuit,As for the ohmic resistance component in the second test circuit, it can be understood that in the first test circuit, since the frequency of the first current test signal is higher and the electric double layer capacitor C1 is in a short circuit state, the measurement of the polarization resistance component will be ignored at this time, and the total internal resistance value detected by the secondary cell tab tearing detection device isIn the second test circuit, since the frequency of the first current test signal is low and the electric double layer capacitor C2 is in an off state, the polarization resistance component is synchronously measured at this time, and the total internal resistance value detected by the secondary cell tab tearing detection device isFor example, in one implementation manner, the conventional ac internal resistance tester applies a sine wave current test signal of 1KHz to the secondary battery cell to be detected to measure the impedance of the secondary battery cell to be detected, at this time, since the frequency of the sine wave current test signal is relatively large and is not in the first target frequency interval, the internal test circuit of the secondary battery cell to be detected may refer to (a) in fig. 3, which results in that the polarization resistance value generated by the secondary battery cell to be detected under the polarization effect is not detected, and finally the detection accuracy of the tab tearing detection on the secondary battery cell is affected.

As an example, step 202 includes that after determining that the load adjustment of the secondary battery cell to be detected is completed, if the upper computer detects that the standing time period of the secondary battery cell to be detected at the first preset temperature is longer than the preset standing time period, the upper computer selects a first target frequency in a first target frequency interval, and controls the ac internal resistance tester to apply a first current test signal of the first target frequency to the secondary battery cell to be detected.

In an embodiment, referring to fig. 4, fig. 4 is a second schematic diagram of a local process in a battery preparation process, where a direct current internal resistance test procedure is replaced by a secondary battery lug tearing test procedure, that is, the secondary battery lug tearing test device provided by this embodiment replaces a traditional direct current internal resistance test device to test the total impedance of the secondary battery to be tested, and other processes in this local process may refer to the above-mentioned related contents in explaining fig. 2, which are not repeated herein, and further after the secondary battery is subjected to lug tearing test by the secondary battery lug tearing test device, since the secondary battery lug tearing test device can provide conditions for accurately detecting the total impedance of the secondary battery to be tested, it is able to lay a foundation for improving the accuracy of detecting the lug tearing test of the secondary battery.

It can be understood that, because the preparation process flow of the secondary battery core is complex, and a great amount of manpower and material resources are required in the process, if the situation of tearing of the electrode lug of the secondary battery core can be detected early, the effective foolproof in the battery preparation process can be realized, so that the preparation cost is reduced as much as possible, for example, a plurality of processes such as high Wen Jinrun, formation and standing still exist between the existing testing device of the production line and the electrode lug welding process after the capacity division process, and in the processes such as formation, capacity division and standing still, the total impedance of the secondary battery core to be detected is not obviously changed, and further in an implementation mode, for example, referring to fig. 5, fig. 5 is a third schematic diagram of the local process in the battery preparation process, wherein the detection process of tearing of the secondary battery core electrode lug is set after the high temperature, that is, the total impedance of the secondary battery core to be detected is measured by setting the secondary battery core electrode lug tearing detection device, and the original impedance of the secondary battery core to be detected after the third time is cancelled, and the secondary battery core to be detected after the normal temperature is kept at the time is kept at the constant temperature, so that the time of fully soaking is still required to be kept after the secondary battery core detection is set for the detection, and the secondary battery core is kept at a high temperature after the detection process is fully kept at Wen Jinrun.

As another example, step 202 includes that, after determining that the secondary battery cell to be detected completes infiltration at the second preset temperature, if the upper computer detects that the standing time period of the secondary battery cell to be detected at the third preset temperature is longer than the preset standing time period, the upper computer selects a first target frequency in a first target frequency interval, and controls the resistance measurement device to apply a first current test signal of the first target frequency to the secondary battery cell to be detected, where the first preset temperature and the second preset temperature may both be set to normal temperature, for example, 25 ℃, and the third preset temperature may be set to high temperature, for example, 50 ℃.

And 204, testing the test resistance value of the secondary battery cell to be detected according to the first current test signal.

It should be noted that, when the resistance measurement of the secondary battery cell to be detected is performed by the resistance measurement device, the first current test signal may be applied to the secondary battery cell to be detected to measure the test resistance value of the secondary battery cell to be detected in real time, it may be understood that the conventional DCIR device needs to be configured with a charge-discharge power module, for example, an independent power module is configured for each secondary battery cell channel, so that the measurement of the current and the voltage of the secondary battery cell to be detected may be implemented, and finally, the calculated ratio of the voltage drop before and after the test and the current is used as the resistance value of the secondary battery cell to be detected.

As an example, step 204 includes receiving a test resistance value of a secondary cell to be detected based on a first current test signal feedback.

And 206, determining an actual resistance value obtained by calibrating the test resistance value in the actual test process, and carrying out tab tearing detection on the secondary battery cell to be detected according to the magnitude relation between the actual resistance value and the preset resistance value.

It should be noted that, due to the influence of factors such as objective environment, the measured test resistance values may be different, and further, by performing the test resistance value calibration process, the stability of the impedance condition of the secondary battery cell to be detected may be ensured, after the actual resistance value is obtained, the detection of the tab tear of the secondary battery cell to be detected may be completed based on the magnitude relation between the actual resistance value and the preset resistance value, for example, in an implementation manner, the preset resistance value is taken to be 0.18, the tab tear of the secondary battery cell to be detected is determined under the condition that the actual resistance value is greater than the preset resistance value, and the tab tear of the secondary battery cell to be detected is determined under the condition that the actual resistance value is less than or equal to the preset resistance value.

Step 206 includes testing to obtain a first resistance value, a second resistance value and a third resistance value of the secondary battery cell to be detected according to a first current test signal, performing averaging processing on the first resistance value, the second resistance value and the third resistance value to obtain an actual resistance value of the secondary battery cell to be detected, wherein the first resistance value, the second resistance value and the third resistance value are obtained by testing the secondary battery cell to be detected respectively through first current test signals with first target frequencies applied at different time points, namely, testing the resistance values obtained through internal resistance measuring devices at different time points, determining that the secondary battery cell to be detected has a tab tear when the actual resistance value is detected to be greater than a preset resistance value, and determining that the secondary battery cell to be detected does not have the tab tear when the actual resistance value is detected to be less than or equal to the preset resistance value.

It can be understood that the factor causing the self-discharge failure is not only the tearing of the tab, but also other failure factors such as pole piece burrs, internal metal foreign matters, internal micro-short circuits and the like, so that whether the secondary battery core to be detected has the tearing of the tab is judged, battery parts can be disassembled, and the quality problem of ultrasonic welding of the multilayer current collector is manually checked.

In the secondary battery cell tab tearing detection method, from the deployment of the secondary battery cell tab tearing detection device, the secondary battery cell tearing detection device is in contact connection with the secondary battery cell to be detected, the secondary battery cell to be detected is provided with a positive electrode and a negative electrode, an electric double layer capacitor is formed between the positive electrode and the negative electrode of the secondary battery cell to be detected in the infiltrated electrolyte, after the secondary battery cell to be detected is fully infiltrated in the electrolyte, the electrochemical reaction between the positive electrode and the negative electrode of the secondary battery cell to be detected is stable, the electric performance of the secondary battery cell can be objectively reflected, and when the secondary battery cell tab device applies a first current test signal to the secondary battery cell to be detected in a first target frequency interval, the electric double layer capacitor is in an open circuit state, so that the impedance part of the electric double layer capacitor in a circuit is not ignored, the resistance change condition of the secondary battery cell under the polarization effect can be captured in real time, the test results show that the test resistance value of the secondary battery cell to be detected is obtained, and then the test resistance value in the actual test process is calibrated, so that the first current test signals with the same frequency are applied to the secondary battery cell to be detected at different time points, the test resistance value obtained in the actual test process is calibrated, the situation that the impedance error in the impedance detection process is carried out on the secondary battery cell to be detected due to time variation can be avoided, the actual resistance value which more accurately represents the impedance situation of the secondary battery cell to be detected can be obtained, the electrode lug tearing detection is carried out on the secondary battery cell to be detected through the magnitude relation between the actual resistance value obtained by the calibration of the test resistance value in the actual test process and the preset resistance value, and the actual resistance value obtained by the calibration of the electrode lug tearing detection device of the secondary battery cell is attached to the actual test process, the method and the device can measure the resistance change condition of the secondary battery cell under the polarization effect, further enable the actual resistance value to reflect the actual resistance condition of the secondary battery cell under the specific state, and finally use the detected actual resistance value as the detection basis for carrying out tab tearing detection on the secondary battery cell to be detected, so that the detection accuracy of tab tearing detection on the secondary battery cell is improved under the conditions that the internal resistance value component of the secondary battery cell which is placed in electrolyte is complex, the DCIR device is total resistance detection which is completed by utilizing the charge and discharge characteristics of the secondary battery cell, the polarization effect in the secondary battery cell can change along with the change of the charge and discharge process and the like.

In one embodiment, as shown in fig. 6, the actual test process includes a first test stage and a second test stage, the first test stage and the second test stage are tested by using first current test signals with different frequencies, the test resistance value includes a first test resistance value measured in the first test stage and a second test resistance value measured in the second test stage, and determining the actual resistance value obtained by calibrating the test resistance value in the actual test process includes:

Step 302, detecting a first polarization resistance value of the secondary battery cell to be detected according to the first test resistance value and the ohmic resistance value of the secondary battery cell to be detected, and detecting a second polarization resistance value of the secondary battery cell to be detected according to the second test resistance value and the ohmic resistance value.

It should be noted that, in the process of calibrating the test resistance value, the impedance of the electric double layer capacitor has the characteristic of changing along with the frequency, so that the first current test signals input in different test stages in the actual test process are different, and the impedance condition of the secondary battery cell to be detected measured obtained by the resistance measurement device is also different, so as to avoid the frequency characteristic impedance error carried by the test resistance value obtained by the test in different target frequencies in the first target frequency interval, and a plurality of test stages can be set in the actual test process, wherein the different test stages adopt different first current test signals for testing, so that the polarization impedance condition of the secondary battery cell to be detected reflected in the first current test signals of different frequencies can be detected, thereby laying a foundation for obtaining the actual resistance value of the secondary battery cell to be detected for the subsequent calibration, and the test resistance value comprises the first test resistance value measured in the first test stage and the second test resistance value measured in the second test stage.

It should be noted that, the ohmic resistance value may be stored in the upper computer in advance, and may be specifically obtained by testing by a conventional internal resistance measurement device, for example, in an implementation manner, in an actual testing process of testing the test resistance value of the secondary battery cell to be detected according to the first current test signal, the test may be divided into a first test stage and a second test stage, where the first test stage tests with a first current test signal of 1Hz, and the second test stage tests with a second current test signal of 0.9Hz, so that the polarization resistance value measured by the first test resistance value and the second test resistance value obtained by testing in different test stages of the secondary battery cell to be detected under the first current test signal of different frequencies may be detected.

As an example, step 302 includes extracting an ohmic resistance value of a secondary cell to be detected, differentiating the first test resistance value with the ohmic resistance value to obtain a first polarization resistance value of the secondary cell to be detected, and differentiating the second test resistance value with the ohmic resistance value to obtain a second polarization resistance value of the secondary cell to be detected.

And step 304, calibrating the polarization resistance of the secondary battery cell to be detected in the actual test process according to the first polarization resistance value and the second polarization resistance value to obtain the target polarization resistance value of the secondary battery cell to be detected.

It should be noted that, in the process of calibrating the polarization resistance of the secondary battery cell in the actual test process, the same weight can be set for the polarization impedance conditions measured by the first current test signals under different frequencies, different polarization resistance values are processed through averaging to obtain a target polarization resistance value, and different weights can be set for the polarization impedance conditions measured by the first current test signals under different frequencies by analyzing the association relationship between the frequencies and the polarization resistance, and the target polarization resistance value of the secondary battery cell to be detected is obtained through fusion calculation.

As an example, step 304 includes performing a process of averaging the first polarization resistance value and the second polarization resistance value to obtain a target polarization resistance value obtained by calibrating the secondary battery cell to be detected in an actual testing process.

As another example, step 304 includes determining a first weight corresponding to the first polarization resistance value and a second weight corresponding to the second polarization resistance value, and obtaining a target polarization resistance value obtained by calibrating the secondary battery cell to be detected in an actual test process by fusing the first polarization resistance value, the second polarization resistance value, the first weight and the second weight.

And 306, taking the sum of the ohmic resistance value and the target polarization resistance value as an actual resistance value.

As one example, step 306 includes summing the ohmic resistance value and the target polarization resistance value to obtain an actual resistance value.

In this embodiment, in the actual testing process of the secondary battery cell to be detected, the actual testing process is divided into a first testing stage and a second testing stage, different first current testing signals are adopted in different testing stages to test the secondary battery cell to be detected, so as to obtain a first testing resistance value and a second testing resistance value of the secondary battery cell to be detected, and further obtain the first polarization resistance value and the second polarization resistance value of the secondary battery cell to be detected, which are measured under the first current testing signals with different frequencies, by using the first testing resistance value and the second testing resistance value, so that the target polarization resistance value of the secondary battery cell to be detected is obtained through calibration, and finally the actual resistance value is obtained through solving, thereby achieving the purpose that the polarization resistance condition of the secondary battery cell to be detected, which is measured under the first current testing signal with the target polarization resistance value and applied in the first target frequency interval, is objectively represented, so as to obtain the accurate actual resistance value, and further lay the foundation for further improving the detection performance of tearing of the secondary battery cell.

In one embodiment, the preset resistance value includes a first preset resistance value and a second preset resistance value, the first preset resistance value is smaller than the second preset resistance value, the first preset resistance value isThe second preset resistance value is,AndThe following respectively satisfy:, according to the magnitude relation between the actual resistance value and the preset resistance value, the tab tearing detection is carried out on the secondary battery cell to be detected, and the method comprises the following steps:

After the secondary battery cell to be detected is formed, a second current test signal is applied to the secondary battery cell to be detected in a second target frequency interval, wherein the electric double layer capacitor is in a short circuit state in the second target frequency interval, and the first target frequency interval is The second target frequency interval isThe method comprises the steps of detecting a charge-discharge resistance value of a secondary battery cell to be detected according to a second current test signal, determining a resistance difference value between an actual resistance value and the charge-discharge resistance value, determining that a tab tear exists in the secondary battery cell to be detected when the actual resistance value is detected to be larger than a first preset resistance value or determining that a tab tear does not exist in the secondary battery cell to be detected when the actual resistance value is detected to be smaller than or equal to the first preset resistance value if the resistance difference value is smaller than the preset resistance value, and determining that the tab tear exists in the secondary battery cell to be detected when the actual resistance value is detected to be larger than the second preset resistance value or determining that the tab tear does not exist in the secondary battery cell to be detected if the actual resistance value is detected to be smaller than or equal to the second preset resistance value.

It should be noted that, in order to further improve the accuracy of detecting the situation of tearing the tab of the secondary battery cell to be detected, the ac internal resistance tester of the secondary battery cell tab tearing device may be used in different procedures of the measuring process of the actual resistance value, where the charge-discharge resistance value measured by the ac internal resistance tester before the secondary battery cell to be detected is formed is used to verify the stability of the internal resistance characteristic of the secondary battery cell to be detected in the actual testing process, where the charge-discharge resistance value refers to the quantized value of the secondary battery cell to be detected on the current blocking effect under the specific charge-discharge condition, the specific charge-discharge condition may be specific charge condition or specific discharge condition, so that the actual resistance value obtained by the secondary battery cell tab tearing device detection and the preset resistance value with different sizes may be used together as the detection basis of the secondary battery cell tab detection, for example, in a practical mode, if the difference between the actual resistance value and the charge-discharge resistance value is smaller, the internal resistance value is indicated to be stable in the internal resistance characteristic of the actual testing process, if the actual resistance value is set in the actual testing process, and if the difference between the actual resistance value and the actual resistance value is larger in the actual tearing process is set, and if the difference between the actual resistance value and the actual tearing situation is larger is determined, and if the actual tearing situation is detected.

It should be noted that the preset resistance value includes a first preset resistance value and a second preset resistance value, the first preset resistance value is smaller than the second preset resistance value, and the first preset resistance value is greater than 0.17And less than 0.19A second preset resistance value of more than 0.19And less than 0.25The second target frequency range refers to a frequency range in which the electric double layer capacitor is in a short circuit state, specifically, the first target frequency range isThe second target frequency interval isThat is, the first target frequency selected in the first target frequency interval is any frequency not less than 0.1Hz and not more than 10Hz, the second target frequency selected in the second target frequency interval is any frequency not more than 10Hz and not more than 1050Hz, in an implementation manner, referring to fig. 7, fig. 7 is a fourth schematic diagram of a local process in the battery preparation process, wherein a secondary battery tab tearing detection procedure is set after high-temperature infiltration, wherein the secondary battery tab tearing detection procedure uses a first current test signal of 1Hz for measuring the total impedance of the secondary battery to be detected by the secondary battery tab tearing detection device, a direct current internal resistance test procedure uses a second current test signal of 1kHz for measuring the total impedance of the secondary battery to be detected by the direct current internal resistance test device after the third normal temperature standing, and it is understood that the direct current internal resistance test procedure can also be set at any position from after formation to before warehousing.

As an example, after the load of the secondary battery cell to be detected is adjusted, if the standing time of the secondary battery cell to be detected at the fourth preset temperature is longer than the preset standing time, selecting a second target frequency in a second target frequency interval, and controlling the ac internal resistance tester to apply a second current test signal to the secondary battery cell to be detected, wherein the electric double layer capacitor is in a short circuit state in the second target frequency interval, and the first target frequency interval isThe second target frequency interval isThe fourth preset temperature may be 25 ℃, receive a charge-discharge resistance value of the secondary battery core to be detected fed back based on the second current test signal, make a difference between an actual resistance value and the charge-discharge resistance value to obtain a resistance difference value, determine that the secondary battery core to be detected has a tab tear if the resistance difference value is smaller than a preset resistance difference threshold value, or determine that the secondary battery core to be detected does not have a tab tear if the actual resistance value is smaller than or equal to the preset resistance value, and determine that the secondary battery core to be detected has a tab tear if the resistance difference value is larger than or equal to the preset resistance difference threshold value, or determine that the secondary battery core to be detected does not have a tab tear if the resistance difference value is smaller than or equal to the preset resistance value.

In this embodiment, the ac internal resistance tester is set to test the secondary battery cell to be detected before formation to obtain the charge-discharge resistance value, and then the secondary battery cell tab tearing detection process using the actual resistance value as the detection basis is assisted by the charge-discharge resistance value, so that it is ensured that preset resistance values with different magnitudes can be set for the actual resistance value as comparison objects under different conditions, and finally, whether the secondary battery cell to be detected has tab tearing conditions or not is accurately detected according to the magnitude relation between the actual resistance value and the preset resistance value, so that a foundation is further laid for improving the detection accuracy of tab tearing detection on the secondary battery cell.

In one embodiment, applying a first current test signal to a secondary cell to be detected in a first target frequency interval includes:

And after determining that the secondary battery cell to be detected is qualified based on the initial voltage value, applying a first current test signal to the secondary battery cell to be detected in a first target frequency interval.

It should be noted that, voltage measurement equipment can be further set in the secondary battery cell tab tearing detection device, the detection of the initial voltage value of the electrolyte is performed before formation, so as to prevent the quality risk of the secondary battery cell to be detected, for example, in an implementation manner, the voltage measurement equipment can be a voltmeter, the initial voltage value of the secondary battery cell to be detected, which is soaked in the electrolyte, is detected through the voltmeter set before formation, and under the condition that the voltage of the secondary battery cell to be detected is qualified, the upper computer controls the resistance measurement device to apply the first current test signal in the first target frequency interval to the secondary battery cell to be detected, so that the tab tearing detection is not required to be performed on the secondary battery cell to be detected, and the workload of tab tearing detection on the secondary battery cell is reduced.

As an example, after the secondary battery cell to be detected is soaked in the electrolyte at a high temperature, detecting an initial voltage value of the secondary battery cell to be detected soaked in the electrolyte through a voltmeter, if the initial voltage value is larger than a preset voltage threshold value, determining that the secondary battery cell to be detected is qualified, and after a first target frequency is selected in a first target frequency interval by an upper computer, controlling a resistance measuring device to apply a first current test signal of the first target frequency to the secondary battery cell to be detected.

In this embodiment, by disposing the voltage measurement device in the secondary battery cell tab tearing device, an initial voltage value of the secondary battery cell to be detected immersed in the electrolyte is detected, and after determining that the secondary battery cell to be detected is qualified according to a magnitude relation between the initial voltage value and a preset voltage threshold, a first current test signal is applied to the secondary battery cell to be detected in a first target frequency interval, so that a situation that invalid tab tearing detection is performed on the secondary battery cell to be detected is avoided, and therefore, the detection flexibility of tab tearing detection of the secondary battery cell is synchronously improved while a foundation is laid for improving the detection accuracy of tab tearing detection on the secondary battery cell.

In one embodiment, after the tab tear detection is performed on the secondary battery cell to be detected according to the magnitude relation between the actual resistance value and the preset resistance value, the method further includes:

Detecting total quantity of tab tearing cells of a battery module to which the secondary cell to be detected belongs after the tab tearing cells exist in the secondary cell to be detected, selecting undetected secondary cells in the battery module as secondary cells to be detected according to cell identification information in the battery module if the total quantity of tab tearing cells is smaller than a preset cell total quantity threshold, and outputting abnormal prompt information if the total quantity of tab tearing cells is larger than or equal to the preset cell total quantity threshold, wherein the abnormal prompt information is used for prompting that the tab tearing exists in batch cells in the battery module.

It should be noted that in an actual application scenario, in general, the tab tearing detection is performed on a plurality of secondary battery cells of a certain module, after the current tab tearing condition of the secondary battery cell to be detected is detected, an object for performing the tab tearing detection may be replaced, further after the tab tearing condition detection of all secondary battery cells in the whole battery module is completed, the total amount of tab torn battery cells with tab tearing is counted, and the total amount of tab torn battery cells is taken as an index, the quality of the battery preparation process is controlled, wherein, the abnormal prompt information is used for prompting that a lot of battery cells in the battery module have tab tearing, and may be specifically sound prompt information or text prompt information, for example, in a practical mode, an upper computer monitors the testing process of the battery module in real time, and performs classification statistics on defective products of the secondary battery cells, if the secondary battery cells with poor internal resistance continuously occur in the testing process, the upper computer controls the secondary battery cell tab tearing detection device to trigger abnormal alarm, so as to prompt that the tab quantity is abnormally torn.

The method comprises the steps of updating the total quantity of tab tearing cells of a battery module to which a secondary cell to be detected belongs after the tab tearing of the secondary cell to be detected exists, selecting an undetected secondary cell in the battery module as the secondary cell to be detected according to cell identification information in the battery module if the total quantity of tab tearing cells is smaller than a preset cell total quantity threshold value, and returning to execute the step and the subsequent steps of applying a first current test signal to the secondary cell to be detected in a first target frequency interval after the secondary cell to be detected is fully soaked in electrolyte until all the secondary cells in the battery module are selected as the secondary cell to be detected, and outputting abnormal prompt information if the total quantity of tab tearing cells is larger than or equal to the preset cell total quantity threshold value, wherein the abnormal prompt information is used for prompting that the tab tearing exists in batch cells in the battery module.

In this embodiment, the detection conditions of tearing of the tabs of all secondary battery cells of the battery module to which the secondary battery cell belongs are integrated, so that the detection flow of tearing of the tabs of the secondary battery cell of the battery module is monitored in real time, and timely early warning is performed through abnormal prompt information under the condition that batch welding tearing abnormality occurs, so that the purpose of effectively controlling the detection conditions of tearing of the tabs of batch battery cells in the battery module can be achieved, and a foundation is laid for improving the detection effect of the detection of tearing of the tabs of the secondary battery cell.

It should be understood that, although the steps in the flowcharts related to the above embodiments are sequentially shown as indicated by arrows, these steps are not necessarily sequentially performed in the order indicated by the arrows. The steps are not strictly limited to the order of execution unless explicitly recited herein, and the steps may be executed in other orders. Moreover, at least some of the steps in the flowcharts described in the above embodiments may include a plurality of steps or a plurality of stages, which are not necessarily performed at the same time, but may be performed at different times, and the order of the steps or stages is not necessarily performed sequentially, but may be performed alternately or alternately with at least some of the other steps or stages.

Based on the same inventive concept, the embodiment also provides a secondary battery cell tab tearing detection device for realizing the secondary battery cell tab tearing detection method. The implementation scheme of the device for solving the problem is similar to that described in the above method, so the specific limitation of the embodiment of the device for detecting the tearing of the secondary battery cell tab provided below can be referred to the limitation of the method for detecting the tearing of the secondary battery cell tab hereinabove, and will not be repeated here.

In one exemplary embodiment, a secondary battery cell tab tearing detection device is provided, comprising a resistance measurement device and an upper computer, wherein the resistance measurement device is in contact connection with a secondary battery cell to be detected, the resistance measurement device is in communication connection with the upper computer, the upper computer comprises an application module and a detection module, the secondary battery cell to be detected is fixed with a tab, the secondary battery cell to be detected comprises an anode and a cathode, an electric double layer capacitor is formed between the anode and the cathode in immersed electrolyte,

The detection module is used for determining an actual resistance value obtained by calibrating a test resistance value in an actual test process, and carrying out tab tearing detection on the secondary battery cell to be detected according to the magnitude relation between the actual resistance value and a preset resistance value.

In one embodiment, the secondary battery cell tab tearing detection device further comprises a charging and discharging power supply module, the charging and discharging power supply module is in contact connection with the secondary battery cell to be detected, and the charging and discharging power supply module is used for detecting the charging and discharging resistance value of the secondary battery cell to be detected according to a second current test signal applied to the secondary battery cell to be detected by the upper computer in a second target frequency interval.

It should be noted that, by setting the ac internal resistance tester and testing the ac internal resistance tester before the secondary battery cell to be detected is formed, then the secondary battery cell tab tearing detection process using the actual resistance value as the detection basis is assisted by the charge-discharge resistance, a charge-discharge power module can be deployed at the secondary battery cell tab tearing detection device, the charge-discharge power module can be in contact connection with the secondary battery cell to be detected through a test probe and the like, and the charge-discharge power module is used for detecting the charge-discharge resistance of the secondary battery cell to be detected according to a second current test signal applied to the secondary battery cell to be detected by the upper computer in a second target frequency interval.

In one embodiment, the secondary battery cell tab tearing detection device further comprises a voltage measurement device, wherein the voltage measurement device is in contact connection with the secondary battery cell to be detected, and the voltage measurement device is used for detecting an initial voltage value of the secondary battery cell to be detected immersed in the electrolyte before the secondary battery cell to be detected is formed.

It should be noted that, in order to prevent the quality risk of the secondary battery cell to be detected, the secondary battery cell tab tearing detection device may be further configured to deploy a voltage measurement device, where the voltage measurement device is configured to detect an initial voltage value of the secondary battery cell to be detected immersed in the electrolyte before the secondary battery cell to be detected is formed, and specifically, the voltage measurement device may be a voltmeter, where the voltage measurement device is connected to the secondary battery cell to be detected through a test probe in a contact manner.

In one embodiment, the resistance measurement device is provided with a resistance test probe, the voltage measurement device is provided with a voltage test probe, the resistance test probe and the voltage test probe are isolated through an insulator, the secondary battery cell tab tearing detection device further comprises a motion assembly, the motion assembly comprises a driving part, a guiding part, a first positioning part and a supporting part, a battery module to be detected of the secondary battery cell is assembled on a loading platform, the supporting part supports the loading platform, a second positioning part is arranged on the loading platform, after the loading platform is located at a target position, the driving part drives the first positioning part and the second positioning part to perform positioning fit under the action of the guiding part, and after the positioning fit is completed, the resistance test probe is respectively contacted with a first position of the positive electrode and a second position of the negative electrode, and the voltage test probe is respectively contacted with a third position of the positive electrode and a fourth position of the negative electrode, wherein the first position, the second position, the third position and the fourth position are different in pairs.

It should be noted that, the resistor test probe and the voltage test probe are isolated by an insulator to prevent a short circuit phenomenon, specifically, the insulator may be polytetrafluoroethylene or silica gel, in order to facilitate a user to check panel data on the secondary battery cell tab tearing detection device, a four-wire wiring method may be adopted to connect the secondary battery cell to be detected with the resistor measurement device and the voltage measurement device, where the resistor measurement device is an impedance tester, the voltage measurement device is a voltmeter, and the voltmeter and the impedance tester are respectively fixed in the front direction of the secondary battery cell tab tearing detection device; in addition, the secondary battery cell tab tearing detection device is further provided with a motion assembly so as to meet the motion requirement of the secondary battery cell tab tearing detection device in the actual test process.

In an implementation manner, the driving component can be an air cylinder, the guiding component can be a guide pillar, the first positioning component can be a positioning pin, the supporting component can be a supporting rod, the bearing platform is a tray, the battery module of the secondary battery core to be detected is loaded in the tray, the tray is supported by the supporting rod, a positioning hole (second positioning component) is formed in the tray, the moving component drives the tray to move to a target position under the control of the host computer, the target position can be a testing initial position appointed by a user, after the target position, the air cylinder at the left side and the right side can drive the positioning pin and the positioning hole to mutually cooperate under the action of the guide pillar, positioning is completed in the horizontal direction, the resistance measuring device is connected with the secondary battery core to be detected, which is borne on the tray, through the voltage test probe, the voltage test probe and the resistance test probe are fixed on the fixed plate, and contact with the positive and negative poles of the secondary battery core to be detected through different positions, so that an initial voltage value, a second position, a fourth position and a fourth position are formed, and a second voltage value are acquired, and a third position are realized.

It can be understood that the secondary battery cell tab tearing detection device capable of automatically moving adopts a mode that a bearing platform bears a battery module to which a secondary battery cell to be detected belongs, and after the bearing platform moves in place, the secondary battery cell tab tearing detection device can continuously detect the secondary battery cell in the battery module, and the mechanism does not need to move in the test process, so that the influence on precision during movement is avoided.

In one embodiment, the secondary battery cell tab tearing detection device further comprises an information collector and a relay conversion plate, wherein the information collector and the relay conversion plate are respectively in communication connection with the upper computer, the information collector is used for collecting battery cell identification information in a battery module to which the secondary battery cell to be detected belongs and sending the battery cell identification information to the upper computer, and the relay conversion plate is used for converting a current test channel from a first target secondary battery cell to a second target secondary battery cell identified by the battery cell identification information according to a conversion instruction issued by the upper computer, wherein the first target secondary battery cell and the second target secondary battery cell are different secondary battery cells in the battery module.

It should be noted that, the secondary battery cell tab tearing detection device is further provided with an information collector and a relay conversion plate, wherein the information collector is responsible for realizing collection of battery cell identification information, the battery cell identification information can be specifically a battery cell number, different secondary battery cells in the battery module can be accurately positioned through the battery cell identification information, the information collector can be specifically a scanner, the relay conversion plate is responsible for realizing switching of the current test channel among different secondary battery cells in the battery module, and it can be understood that the first target secondary battery cell and the second target secondary battery cell can be used as secondary battery cells to be detected at different time points of secondary battery cell tab tearing detection.

Therefore, compared with the traditional DCIR device which adopts a mode of moving the test probes by the moving mechanism, the method has the advantages that the efficiency in mass production is lower, the number of secondary battery cells is selected to be in one-to-one correspondence with the number of the test probes, the electronic relay conversion plate is not required to be used for converting the test channels, and the conversion process is faster than that of physically moving the probes, so that the efficiency is higher.

Referring to fig. 8, fig. 8 is a schematic diagram of a local module of a secondary battery lug tearing detection device, in which, in the schematic diagram of the module, the secondary battery lug tearing detection device may include a voltmeter 400, an ac impedance tester 401, a guide pillar 402, a cylinder 403, a conveyor line 404, a positioning pin 405, a positioning hole 406, a test probe 407, a relay conversion board 408, a tray 409, a scanner 410 and a host computer 411, in which, the test probe 407 may include a voltage test probe 4071 and a current test probe 4072, the secondary battery lug to be detected by the secondary battery lug tearing detection device may be detected by the secondary battery lug tearing detection device, the actual resistance value may be used as a detection basis to detect the secondary battery lug tearing of any secondary battery lug, and the secondary battery lug tearing detection device may also be controlled according to the situation and process of the batch battery lug tearing of the secondary battery lug in the battery module, so that, by the secondary battery lug tearing detection device provided by the embodiment, the secondary battery lug tearing detection device may not only be able to increase the accuracy of the secondary battery lug tearing detection, but also be able to increase the detection of the secondary battery lug tearing detection by the secondary battery lug, and the four-wire lug detection device may also be able to automatically increase the efficiency by the method, and the secondary battery lug tearing detection device may be able to realize the continuous detection by the current test mode by the relay conversion board after the secondary battery lug tearing detection device and the current detection by the current detection mode, and the secondary battery lug detection device may be able to realize the continuous detection by the continuous detection mode, with the different secondary electric cores in the detection battery module to can avoid secondary electric core tab to tear detection device and carry out the condition that too much moved in the testing process, so, also can overcome secondary electric core tab and tear detection device and treat the influence of the test resistance value test accuracy of detecting secondary electric core in the motion process, so, further promoted and waited to detect the detection accuracy that detects to secondary electric core carries out tab tearing.

It can be understood that when different detection devices are used to detect secondary batteries with different capacities, actual resistance values obtained by detecting the secondary batteries by the different detection devices are different, so that the secondary battery tab tearing conditions obtained by detecting the actual resistance values as detection basis are different, as shown in table 1, table 1 is a comparison table of detection data of an ac resistance tester and a dc internal resistance tester, which are indicative of the secondary battery tab tearing detection devices, wherein table 1 is as follows:

Table 1:

It can be understood that in the conventional manner, the ac resistance tester uses a 1kHz current test signal to perform the impedance condition test of the secondary battery cell, while in the present embodiment, the ac resistance tester uses a 1Hz current test signal to perform the impedance condition test of the secondary battery cell, as shown in the test data in table 1 above, it is known that in different secondary battery packs, there is a difference in the resistance values measured in the same test manner, and thus there is a slight difference in the results of the secondary battery cell tab tear detection, while in the same secondary battery pack, the resistance values measured by the ac resistance tester using a 1Hz current test signal are used as detection basis, the tab tear condition detection of 9120 secondary battery cells is performed, the obtained detection rate is 99.8%, the resistance values measured by the ac resistance tester using a 1kHz current test signal are used as detection basis, the obtained detection rate is 98.50%, the obtained detection rate is 97.20% by taking the resistance value measured by the current test signal adopted by the direct current internal resistance tester as the detection basis, so the secondary battery cell tab tearing detection device adopted by the embodiment has higher accuracy compared with the traditional secondary battery cell tab tearing detection mode, in particular, compared with the same type of secondary battery cell impedance test mode, because the impedance condition test of the secondary battery cell is carried out by the current test signal of 1Hz, compared with the impedance condition test of the secondary battery cell is carried out by the current test signal of 1kHz, the actual impedance condition of the secondary battery cell can be reflected more truly, thereby the accuracy of the overall secondary battery cell tab tearing detection of the battery pack is obviously improved, compared with different types of secondary battery cell impedance test modes, compared with the impedance condition test of the secondary battery core by using a direct current internal resistance test device, the impedance condition test of the secondary battery core by using a 1Hz current test signal can reflect the actual impedance condition of the secondary battery core more truly, so that the accuracy of the overall secondary battery core tab tearing detection of the battery module is improved to a certain extent, and meanwhile, the direct current internal resistance test device can relatively accurately detect the overall secondary battery tab tearing of the battery pack, but in the secondary battery tab tearing detection device of the embodiment, the test procedure is relatively forward due to the impedance condition test of the secondary battery core by using the 1Hz current test signal, and further the cost consumption caused by the secondary battery tab tearing phenomenon can be prevented from being detected only in the later procedure, so that the aim of carrying out tab welding tearing phenomenon effective foolproof on the battery pack can be realized, and the detection effect of the secondary battery tab tearing detection is improved from multiple dimensions such as detection cost and detection accuracy.

All or part of each module in the secondary battery cell tab tearing detection device can be realized by software, hardware and a combination thereof.

In one embodiment, a secondary battery is further provided, the secondary battery comprises a secondary battery cell, and the secondary battery cell is torn in an electrodeless ear manner, wherein the detection result of the tearing of the secondary battery cell is detected by the detection method of tearing of the electrode ear of the secondary battery cell.

In one embodiment, there is also provided an energy storage system including the secondary battery as above, the specific structure of the secondary battery referring to the above-described embodiments. Because the energy storage system adopts all the technical schemes of all the embodiments, the energy storage system at least has all the beneficial effects brought by the technical schemes of the embodiments, and the description is omitted herein.

In an embodiment, an electric device is further provided, and the electric device includes an energy storage system, and the specific structure of the energy storage system refers to the above embodiment, and because the electric device adopts all the technical solutions of all the above embodiments, at least has all the beneficial effects brought by the technical solutions of the above embodiments, and will not be described in detail herein.

The technical features of the above embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The foregoing examples illustrate only a few embodiments of the application, which are described in detail and are not to be construed as limiting the scope of the application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of the application should be assessed as that of the appended claims.

Claims

1. A secondary battery cell tab tear detection method, characterized in that it is applied to a secondary battery cell tab tear detection device, the secondary battery cell tab tear detection device is contact-connected with a secondary battery cell to be detected, the secondary battery cell to be detected is fixed with a tab, the secondary battery cell to be detected comprises a positive electrode and a negative electrode, and a double-layer capacitor is formed between the positive electrode and the negative electrode in an infiltrated electrolyte; the method comprises:

After the secondary battery cell to be tested is fully immersed in the electrolyte, a first current test signal is applied to the secondary battery cell to be tested within a first target frequency range, wherein the double-layer capacitor is in an open circuit state within the first target frequency range;

Testing the test resistance value of the secondary battery cell to be tested according to the first current test signal;

An actual resistance value obtained by calibrating the test resistance value during the actual test process is determined, and based on the magnitude relationship between the actual resistance value and the preset resistance value, a tab tearing detection is performed on the secondary battery cell to be detected.

2. The method according to claim 1, characterized in that the actual test process includes a first test phase and a second test phase, the first test phase and the second test phase use first current test signals of different frequencies for testing, the test resistance value includes a first test resistance value measured in the first test phase and a second test resistance value measured in the second test phase; the determining the actual resistance value obtained by calibrating the test resistance value during the actual test process comprises:

Detecting a first polarization resistance value of the secondary cell to be detected according to the first test resistance value and the ohmic resistance value of the secondary cell to be detected, and detecting a second polarization resistance value of the secondary cell to be detected according to the second test resistance value and the ohmic resistance value;

According to the first polarization resistance value and the second polarization resistance value, calibrating the polarization resistance of the secondary battery cell to be tested during the actual test process to obtain a target polarization resistance value of the secondary battery cell to be tested;

The sum of the ohmic resistance value and the target polarization resistance value is taken as the actual resistance value.

3. The method according to claim 1, characterized in that the preset resistance value includes a first preset resistance value and a second preset resistance value, the first preset resistance value is smaller than the second preset resistance value, and the first preset resistance value is The second preset resistance is , and Respectively meet: , ; The step of performing a tab tear detection on the secondary battery cell to be detected according to the magnitude relationship between the actual resistance value and the preset resistance value comprises:

After the secondary battery cell to be tested is formed, a second current test signal is applied to the secondary battery cell to be tested within a second target frequency interval, wherein the double-layer capacitor is in a short-circuit state within the second target frequency interval, and the first target frequency interval is , the second target frequency interval is ;

Detecting the charge and discharge resistance value of the secondary battery cell to be detected according to the second current test signal;

Determining a resistance difference between the actual resistance value and the charge and discharge resistance value;

If the resistance difference is less than the preset resistance difference threshold, then when it is detected that the actual resistance value is greater than the first preset resistance value, it is determined that the tab of the secondary battery cell to be detected is torn, or when it is detected that the actual resistance value is less than or equal to the first preset resistance value, it is determined that the tab of the secondary battery cell to be detected is not torn;

If the resistance difference is greater than or equal to the preset resistance difference threshold, then when it is detected that the actual resistance value is greater than the second preset resistance value, it is determined that the tab of the secondary battery cell to be tested has been torn, or when it is detected that the actual resistance value is less than or equal to the second preset resistance value, it is determined that the tab of the secondary battery cell to be tested does not have been torn.

4. The method according to claim 1, characterized in that applying a first current test signal to the secondary battery cell to be tested within the first target frequency range comprises:

Before the secondary battery cell to be detected is formed, detecting an initial voltage value of the secondary battery cell to be detected when immersed in the electrolyte;

After determining that the secondary battery cell to be detected is qualified based on the initial voltage value, the first current test signal is applied to the secondary battery cell to be detected within a first target frequency range.

5. The method according to claim 1, characterized in that after performing the tab tearing detection on the secondary battery cell to be detected according to the magnitude relationship between the actual resistance value and the preset resistance value, the method further comprises:

After the to-be-detected secondary battery cell has tab tearing, detecting the total amount of tab-torn batteries in the battery module to which the to-be-detected secondary battery cell belongs;

If the total amount of the torn tab cells is less than a preset total cell threshold, selecting an undetected secondary cell in the battery module as the secondary cell to be detected according to the cell identification information in the battery module;

If the total amount of the tab-torn battery cells is greater than or equal to a preset total amount threshold of the battery cells, an abnormal prompt message is output, wherein the abnormal prompt message is used to prompt that the batch of battery cells in the battery module have tab torn.

6. A secondary battery cell tab tear detection device, characterized in that the secondary battery cell tab tear detection device comprises a resistance measuring device and a host computer, the resistance measuring device is contact-connected to the secondary battery cell to be detected, the resistance measuring device is communicatively connected to the host computer, the host computer comprises an application module and a detection module, the secondary battery cell to be detected is fixed with a tab, the secondary battery cell to be detected comprises a positive electrode and a negative electrode, and a double-layer capacitor is formed between the positive electrode and the negative electrode in the infiltrated electrolyte; wherein,

The applying module is used to apply a first current test signal to the secondary battery cell to be detected within a first target frequency range after the secondary battery cell to be detected is fully immersed in the electrolyte, wherein the double-layer capacitor is in an open circuit state within the first target frequency range;

The resistance measuring device is used to test the test resistance value of the secondary battery cell to be tested according to the first current test signal;

The detection module is used to determine the actual resistance value of the test resistance value calibrated during the actual test process, and perform a tab tear detection on the secondary battery cell to be detected based on the size relationship between the actual resistance value and the preset resistance value.

7. The device according to claim 6 is characterized in that the secondary battery cell tab tearing detection device also includes a charge and discharge power supply module, which is contact-connected to the secondary battery cell to be detected, and is used to detect the charge and discharge resistance value of the secondary battery cell to be detected based on the second current test signal applied by the host computer to the secondary battery cell to be detected within the second target frequency range.

8. The device according to claim 6 is characterized in that the secondary battery cell tab tearing detection device also includes a voltage measuring device, which is contact-connected to the secondary battery cell to be detected, and the voltage measuring device is used to detect the initial voltage value of the secondary battery cell to be detected when it is immersed in the electrolyte before the secondary battery cell to be detected is formed.

9. The device according to claim 8 is characterized in that the resistance measuring device is provided with a resistance test probe, the voltage measuring device is provided with a voltage test probe, the resistance test probe and the voltage test probe are isolated by an insulator, the secondary battery cell tab tear detection device further comprises a motion component, the motion component comprises a driving component, a guide component, a first positioning component and a supporting component, the battery module to which the secondary battery cell to be detected belongs is loaded on a loading platform, the supporting component supports the loading platform, and a second positioning component is provided on the loading platform,

After the loading platform is located at the target position, the driving component drives the first positioning component and the second positioning component to perform positioning cooperation under the action of the guiding component, and after the positioning cooperation is completed, the resistance test probe contacts the first position of the positive pole and the second position of the negative pole respectively, and the voltage test probe contacts the third position of the positive pole and the fourth position of the negative pole respectively, wherein the first position, the second position, the third position and the fourth position are different from each other.

10. The device according to claim 6, characterized in that the secondary battery cell tab tear detection device further comprises an information collector and a relay conversion board, and the information collector and the relay conversion board are respectively connected to the host computer for communication; wherein,

The information collector is used to collect the cell identification information in the battery module to which the secondary cell to be tested belongs, and send the cell identification information to the host computer. The relay conversion board is used to convert the current test channel from the first target secondary cell to the second target secondary cell identified by the cell identification information according to the conversion instruction issued by the host computer, wherein the first target secondary cell and the second target secondary cell are different secondary cells in the battery module.

11. A secondary battery, characterized in that the secondary battery comprises a secondary battery cell, and the secondary battery cell has no tab tearing, wherein the detection result of the secondary battery cell having no tab tearing is obtained by detection using the method according to any one of claims 1 to 5.

12 . An energy storage system, characterized in that the energy storage system comprises a plurality of secondary batteries according to claim 11 .

13. An electrical equipment, characterized in that the electrical equipment comprises the energy storage system according to claim 12.