A simulated charging system for lithium battery chip testing

Abstract

The present invention belongs to the technical field of simulated charging. The present invention provides a simulated charging system for testing a lithium battery chip, comprising: based on processing and analyzing the charging current, an analysis signal is obtained; based on the charging current in a current deviation period, a current change curve is constructed; the current change curve is processed and analyzed to obtain a sharp change value, and whether the charging current changes sharply during constant current charging is judged; according to the charging current when the analysis signal is generated, a voltage control value is obtained by processing, and the charging voltage of the simulated charging system is adjusted according to the voltage control value; the charging voltage of the lithium battery is monitored in real time, and a switching risk value is obtained by processing and analyzing, and whether to stop the simulation system from performing simulated charging on the lithium battery is judged according to the switching risk value, thereby reducing the risk of lithium battery damage caused by untimely switching of the simulated charging system and ensuring the safety of simulated charging.

Description

Technical Field

[0001] The invention belongs to the technical field of simulated charging, in particular to a simulated charging system for testing a lithium battery chip. Background Art

[0002] In the development and production of lithium batteries, it is crucial to accurately evaluate their performance under various working conditions. Existing lithium battery testing systems often have deficiencies in charging current stability and charging mode switching. Therefore, it is of great significance to develop a lithium battery testing system that can simulate temperature changes in actual use environments.

[0003] A Chinese patent application with publication number CN117949835A discloses a simulated charging system for testing lithium battery chips, including: generating a usage status coefficient from a battery status data set; if the usage status coefficient exceeds a status threshold, performing a simulated test on the lithium battery according to a simulated charging scheme, and adjusting the voltage and current during the test to within an expected range; performing a preliminary test on the lithium battery before reaching a cutoff condition, and aggregating the monitoring data to construct a battery test status set; generating an abnormality from the test status set, and if the abnormality exceeds a risk threshold, terminating the charging test; generating a battery quality coefficient from an indicator data set, and if the quality coefficient is lower than a preset quality threshold, providing a lithium battery maintenance plan from a lithium battery optimization knowledge graph.

[0004] In the prior art, the simulated charging test of lithium batteries needs to undergo constant current and constant voltage charging tests, but in practice, the simulated charging process will be affected by many factors, such as environmental influences, and the influence of equipment software and hardware, which will cause the charging current to deviate from the preset constant current in the actual simulated charging. If there is a lack of stable monitoring and timely adjustment, the safety of the simulated charging of lithium batteries cannot be guaranteed. In addition, during the simulated charging process, the safety of the simulated charging is also affected by the switching of charging modes. If the simulated charging system cannot accurately perform the charging mode switching, the battery voltage or current will exceed its test range, thereby causing damage to the battery.

[0005] To this end, the present invention provides a simulated charging system for testing a lithium battery chip. Summary of the invention

[0006] In order to make up for the deficiencies of the prior art, at least one technical problem raised in the background technology is solved.

[0007] The technical solution adopted by the present invention to solve the technical problem is: a simulated charging system for testing lithium battery chips, comprising:

[0008] Constant current charging analysis module: During the simulated charging cycle, the charging current of the simulated charging system is monitored in real time when the simulated charging system performs constant current charging on the lithium battery chip. The analysis signal is obtained based on the processing and analysis of the charging current. The current deviation period is obtained based on the generation time of the analysis signal. The current change curve is constructed based on the charging current in the current deviation period. The current change curve is processed and analyzed to obtain the sharp change value;

[0009] Constant current charging identification module: determines whether the charging current changes sharply during constant current charging based on the sharp change value, and if so, generates an adjustment signal;

[0010] Constant current charging adjustment module: Based on the adjustment signal, the charging current when the analysis signal is generated is processed to obtain the voltage control value, and the charging voltage of the simulated charging system is adjusted according to the voltage control value to achieve the adjustment of the charging current;

[0011] Switching monitoring module: after adjusting the charging current, the charging voltage of the lithium battery is monitored in real time, and the identification signal is obtained by processing and analyzing. Based on the generation time point of the identification signal and the expected generation time point of the constant voltage conversion point, the monitoring and analysis period is obtained. Based on the processing and analysis of the charging current of the simulated charging system and the charging voltage of the lithium battery during the monitoring and analysis period, the switching risk value of the simulated charging system is obtained.

[0012] Switching control module: determines whether to stop the simulation system from simulating charging of the lithium battery according to the switching risk value.

[0013] As a further technical solution of the present invention, the analysis signal is generated in the following manner:

[0014] Monitor the charging current of the simulated charging system in real time. When the charging current of the simulated charging system deviates from the preset constant current during constant current charging, perform difference processing on the charging current of the simulated charging system and the nearest constant current range endpoint value, and take the absolute value of the difference to obtain the charging current difference. Perform ratio processing on the charging current difference and the nearest constant current range endpoint value to obtain the current approximate value.

[0015] comparing the current proximity value with a current proximity threshold;

[0016] If the current proximity value is greater than or equal to the current proximity threshold, an analysis signal is generated;

[0017] The current deviation period is obtained in the following manner:

[0018] Based on the analysis signal, a period between a time point when the charging current deviates from the preset constant current and a time point when the analysis signal is generated is marked as a current deviation period.

[0019] As a further technical solution of the present invention, the method for obtaining the sharp change value is:

[0020] The time deviation value Sjz and the deviation duration value CXz are processed by the formula: The sharp change value Jz is obtained, wherein s1 and s2 are both preset proportional coefficients.

[0021] As a further technical solution of the present invention, the time deviation value Sjz is obtained as follows:

[0022] According to the start time point and the end time point of the current deviation period, the time length of the current deviation period is extracted, and the time length of the current deviation period is compared with the time length of the simulated charging cycle to obtain a time deviation value, which is marked as Sjz;

[0023] The deviation duration value CXz is obtained as follows:

[0024] Obtain the charging current in the current deviation period, construct a two-dimensional coordinate system with the charging current as the Y-axis and the time as the X-axis, mark the charging current in the current deviation period in the coordinate system, and connect the marked charging current data points to obtain a current change curve;

[0025] Divide the current deviation period into a number of deviation sub-periods of equal time length, obtain a portion of the current change curve corresponding to each deviation sub-period, and mark it as a current change sub-curve segment;

[0026] The slope value of the current change sub-curve segment is measured, and the slope value of the current change sub-curve segment is compared with the reference slope value for positive and negative identification. The specific identification and comparison process is as follows:

[0027] If the slope value of the current change sub-curve segment is the same as the corresponding positive and negative of the reference slope value, then the current change sub-curve segment is marked as a same-direction sub-curve segment;

[0028] If the slope value of the current change sub-curve segment is different from the reference slope value in terms of positive and negative sign, the current change sub-curve segment is marked as a non-co-directional sub-curve segment;

[0029] The reference slope value is obtained by connecting the two end points of the current change curve with a straight line to obtain the slope value of the connecting line of the end points of the current change curve, which is the reference slope value;

[0030] The number of the same-direction sub-curve segments is counted and the ratio is processed with the number of all current change sub-curve segments to obtain the deviation duration value, which is marked as CXz.

[0031] As a further technical solution of the present invention, the adjustment signal is generated in the following manner:

[0032] The sharp change value is compared with the sharp change threshold. The specific comparison process is as follows:

[0033] If the change sharp value is greater than or equal to the change sharp threshold, it means that the charging current changes sharply during constant current charging, and an adjustment signal is generated;

[0034] The specific process of obtaining the voltage control value based on the adjustment signal and the charging current when the analysis signal is generated is as follows:

[0035] The charging current of the simulated charging system is obtained when the analysis signal is generated, and the difference between the current and the preset constant current is processed to obtain the deviation current value, and the deviation current value is multiplied by the charging resistance of the simulated charging system to obtain the voltage control value.

[0036] As a further technical solution of the present invention, the switching risk value is obtained in the following manner:

[0037] The switching state value QH is compared with the switching state threshold, and its monitoring and analysis sub-period is marked, specifically:

[0038] If the switching state value QH is greater than or equal to the switching state threshold, the monitoring and analysis sub-period is marked as a suspected waiting switching period;

[0039] If the switching state value QH is less than the switching state threshold, the monitoring and analysis sub-period is marked as a non-suspected waiting switching period;

[0040] If the monitoring and analysis sub-period is marked as a suspected waiting-for-switching period, the charging current at the beginning and the charging current at the end of the suspected waiting-for-switching period are obtained, and the difference is processed to obtain the charging current change difference;

[0041] If the charging current change difference is positive, it means that the charging current in the suspected waiting-for-switching period is on an upward trend as a whole, and the suspected waiting-for-switching period is marked as a non-waiting-for-switching period;

[0042] If the charging current variation is poor, it means that the charging current in the suspected waiting-to-switch period is on a downward trend as a whole, and the suspected waiting-to-switch period is marked as the waiting-to-switch period;

[0043] If the waiting switching period is detected in real time, the interval between the waiting switching period and the last monitoring and analysis sub-period is obtained, and the interval is processed by comparing it with the duration corresponding to the monitoring and analysis period to obtain the switching risk value;

[0044] If the waiting switching period or non-suspected waiting switching period is not monitored in real time, the next monitoring and analysis sub-period will continue to be monitored, and during the monitoring process, the number of remaining monitoring and analysis sub-periods that have not been monitored will be counted in real time, and the number of monitoring and analysis sub-periods will be multiplied by the length of the monitoring and analysis sub-periods to obtain the remaining detection time, and the remaining monitoring time will be ratioed with the length corresponding to the monitoring and analysis period to obtain the switching risk value.

[0045] As a further technical solution of the present invention, the switching state value QH is obtained in the following manner:

[0046] The variance value FC of the slope data group and the current drop ratio XJ are processed by the formula: A switching state value QH is obtained, wherein a1 and a2 are both preset proportional coefficients.

[0047] As a further technical solution of the present invention, the variance value FC of the slope data set is obtained as follows:

[0048] The monitoring and analysis period is divided into several monitoring and analysis sub-periods, and the charging current of the simulation system and the charging voltage of the lithium battery in the sub-period are monitored in real time. The coordinate system is constructed with time as the X-axis and voltage as the Y-axis, and the charging voltage in the monitoring and analysis sub-period is marked and connected in the coordinate system to construct a charging voltage change curve in the monitoring and analysis sub-period. The charging current change curve in the monitoring and analysis sub-period is constructed and obtained in the same way as the construction and acquisition method of the charging voltage change curve;

[0049] The charging voltage variation curve is divided into several voltage sub-curves, the slope of each voltage sub-curve segment is obtained, and they are integrated into a slope data group, and the variance value of the slope data group is obtained and marked as FC.

[0050] As a further technical solution of the present invention, the current drop ratio XJ is obtained in the following manner:

[0051] The charging current variation curve is divided into several current sub-curves, the slope of each current sub-curve is obtained, and the current sub-curve is marked according to the positive or negative slope of the current sub-curve, specifically:

[0052] If the slope of the current sub-curve is positive, its current sub-curve is marked as a growth sub-curve;

[0053] If the slope of the current sub-curve is negative, its current sub-curve is marked as a descending sub-curve;

[0054] The number of decreasing sub-curves is counted and the ratio is processed with the number of all current sub-curves to obtain the current decreasing ratio, which is marked as XJ.

[0055] As a further technical solution of the present invention, the process of determining whether to stop the simulation system from simulating charging the lithium battery is as follows:

[0056] Compare the switching risk value to the switching risk threshold:

[0057] If the switching risk value is greater than or equal to the switching risk threshold, the simulation system is stopped to simulate charging the lithium battery.

[0058] The beneficial effects of the present invention are as follows:

[0059] 1. In a simulated charging cycle, the charging current of the simulated charging system is monitored in real time when the simulated charging system performs constant current charging on the lithium battery chip. An analysis signal is obtained based on the processing and analysis of the charging current. The current deviation period is obtained based on the generation time of the analysis signal. A current change curve is constructed based on the charging current in the current deviation period. The current change curve is processed and analyzed to obtain a sharp change value. Based on the sharp change value, it is judged whether the charging current changes sharply during constant current charging. If so, an adjustment signal is generated. Based on the adjustment signal, a voltage control value is obtained according to the charging current when the analysis signal is generated. The charging voltage of the simulated charging system is adjusted according to the voltage control value to adjust the charging current. The present invention is conducive to stability control of the charging current during the simulated charging process, and is to control in advance when the charging current has a trend of exceeding the charging current range, effectively preventing the problem of the charging current exceeding the charging current range during the simulated charging process, ensuring the safety of the simulated charging of the lithium battery and reducing the risk of damage to the battery due to simulated charging.

[0060] 2. After the adjustment of the charging current is achieved, the charging voltage of the lithium battery is monitored in real time, and the identification signal is obtained by processing and analyzing. Based on the generation time point of the identification signal and the expected generation time point of the constant voltage conversion point, the monitoring and analysis period is obtained. Based on the processing and analysis of the charging current of the simulated charging system and the charging voltage of the lithium battery during the monitoring and analysis period, the switching risk value of the simulated charging system is obtained. According to the switching risk value, it is determined whether to stop the simulated system from performing simulated charging of the lithium battery. The present invention monitors and analyzes the conversion of the charging mode of its simulated charging system, effectively reducing the risk of lithium battery damage caused by untimely switching of the simulated charging system, further ensuring the safety of simulated charging, and indirectly detecting the operating abnormality of the simulated charging system through the monitoring and analysis of the charging mode conversion. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] The present invention will be further described below in conjunction with the accompanying drawings.

[0062] Figure 1 It is a flowchart of a simulated charging system for testing a lithium battery chip according to an embodiment of the present invention;

[0063] Figure 2 It is a flow chart of the steps of switching monitoring in a simulated charging system for testing a lithium battery chip according to an embodiment of the present invention. DETAILED DESCRIPTION

[0064] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0065] Example 1

[0066] like Figure 1 As shown, a simulated charging system for testing a lithium battery chip according to an embodiment of the present invention comprises:

[0067] Constant current charging analysis module: During the simulated charging cycle, the charging current of the simulated charging system is monitored in real time when the simulated charging system performs constant current charging on the lithium battery chip. The analysis signal is obtained based on the processing and analysis of the charging current. The current deviation period is obtained based on the generation time of the analysis signal. The current change curve is constructed based on the charging current in the current deviation period. The current change curve is processed and analyzed to obtain the sharp change value;

[0068] It should be noted that the simulated charging cycle refers to the simulated charging duration set in advance according to the lithium battery charging test requirements;

[0069] In some embodiments, the charging current of the simulated charging system is monitored in real time. When the charging current of the simulated charging system deviates from the preset constant current during constant current charging, the charging current of the simulated charging system is subjected to difference processing with the adjacent and nearest constant current range endpoint value, and the difference is taken as the absolute value to obtain the charging current difference, and the charging current difference is subjected to ratio processing with the adjacent and nearest constant current range endpoint value to obtain the current adjacent value;

[0070] It should be noted that the preset constant current represents the constant charging current that the simulated charging system needs to achieve during constant current charging, and the constant current range represents the current range within which the charging current is allowed to fluctuate during the simulated charging of the lithium battery chip by the simulated system;

[0071] comparing the current proximity value with a current proximity threshold;

[0072] If the current proximity value is greater than or equal to the current proximity threshold, an analysis signal is generated;

[0073] If the current proximity value is less than the current proximity threshold, no operation is performed;

[0074] It should be noted that the current approaching threshold is an empirical value, which is set according to the experience of the staff. The current approaching threshold is a warning value set to prevent the charging current from exceeding the constant current range due to fluctuations when the simulation system simulates charging of the lithium battery.

[0075] Based on the analysis signal, marking the period between the time point when the charging current deviates from the preset constant current and the time point when the analysis signal is generated as a current deviation period;

[0076] According to the start time point and the end time point of the current deviation period, the time length of the current deviation period is extracted, and the time length of the current deviation period is compared with the time length of the simulated charging cycle to obtain a time deviation value, which is marked as Sjz;

[0077] Obtain the charging current in the current deviation period, construct a two-dimensional coordinate system with the charging current as the Y-axis and the time as the X-axis, mark the charging current in the current deviation period in the coordinate system, and connect the marked charging current data points to obtain a current change curve;

[0078] Divide the current deviation period into a number of deviation sub-periods of equal time length, obtain a portion of the current change curve corresponding to each deviation sub-period, and mark it as a current change sub-curve segment;

[0079] The slope value of the current change sub-curve segment is measured, and the slope value of the current change sub-curve segment is compared with the reference slope value for positive and negative identification. The specific identification and comparison process is as follows:

[0080] If the slope value of the current change sub-curve segment is the same as the corresponding positive and negative of the reference slope value, then the current change sub-curve segment is marked as a same-direction sub-curve segment;

[0081] If the slope value of the current change sub-curve segment is different from the reference slope value in terms of positive and negative sign, the current change sub-curve segment is marked as a non-co-directional sub-curve segment;

[0082] It should be noted that the same-direction sub-curve segment means that the current change trend corresponding to the same-direction sub-curve segment is the same as the overall change trend of the current after it deviates from the preset constant current;

[0083] The reference slope value is obtained by connecting the two end points of the current change curve with a straight line to obtain the slope value of the connecting line of the end points of the current change curve, which is the reference slope value;

[0084] Count the number of sub-curve segments in the same direction, and perform ratio processing with the number of sub-curve segments with all current changes to obtain the deviation duration value, which is marked as CXz;

[0085] The obtained time deviation value Sjz and deviation duration value CXz are processed by data, and the formula is: The sharp change value Jz is obtained, where s1 and s2 are both preset proportional coefficients;

[0086] It should be noted that the meaning of the change sharp value Jz is: the change sharp value Jz is calculated by the time deviation value Sjz and the deviation duration value CXz, wherein the time deviation value Sjz reflects the time of the deviation process after the charging current of the simulated charging system deviates from the preset constant current and approaches the end point of the constant current range, wherein the shorter the time, the faster the charging current changes, and conversely, the longer the time, the slower the charging current changes; the deviation duration value CXz reflects the continuity of the charging current change trend during the deviation period after the charging current of the simulated charging system deviates from the preset constant current and approaches the end point of the constant current range; if the deviation time is shorter and the continuity of the charging current change trend is stronger during the deviation process, the charging current changes more sharply, for example, the charging current deviates downward for a very short time, and during the deviation process, the overall deviation trend is a downward trend without any signs of rising, which means that the change of the charging current deviates sharply;

[0087] Constant current charging identification module: determines whether the charging current changes sharply during constant current charging based on the sharp change value, and if so, generates an adjustment signal;

[0088] In some embodiments, the change sharpness value is compared with the change sharpness threshold, and the specific comparison process is as follows:

[0089] If the change sharp value is greater than or equal to the change sharp threshold, it means that the charging current changes sharply during constant current charging, and an adjustment signal is generated;

[0090] If the sharp change value is less than the sharp change threshold, it means that the charging current does not change sharply during constant current charging, and no operation is performed;

[0091] Constant current charging adjustment module: Based on the adjustment signal, the charging current when the analysis signal is generated is processed to obtain the voltage control value, and the charging voltage of the simulated charging system is adjusted according to the voltage control value to achieve the adjustment of the charging current;

[0092] Specifically, the charging current of the simulated charging system is obtained when the analysis signal is generated, and the difference between the current and the preset constant current is processed to obtain a deviation current value, the deviation current value is multiplied by the charging resistance of the simulated charging system to obtain a voltage control value, and the charging voltage of the simulated charging system is adjusted according to the voltage control value;

[0093] The technical solution of the embodiment of the present invention is: in a simulated charging cycle, the charging current of the simulated charging system is monitored in real time when the simulated charging system performs constant current charging on the lithium battery chip, and an analysis signal is obtained based on the processing and analysis of the charging current. The current deviation period is obtained based on the generation time of the analysis signal, and a current change curve is constructed based on the charging current in the current deviation period. The current change curve is processed and analyzed to obtain a sharp change value, and based on the sharp change value, it is judged whether the charging current changes sharply during constant current charging. If so, an adjustment signal is generated, and based on the adjustment signal, a voltage control value is obtained according to the charging current when the analysis signal is generated, and the charging voltage of the simulated charging system is adjusted according to the voltage control value to achieve the adjustment of the charging current. The present invention monitors the charging current of the simulated charging system in real time during the simulated charging process, and when it approaches the constant charging range, the sharpness of its change is analyzed, thereby identifying the control adjustment of its charging current, effectively realizing the monitoring and analysis of the charging current, preventing the charging current from exceeding the constant current range during the simulated charging process, thereby damaging its lithium battery, and ensuring the safety of the simulated charging.

[0094] Example 2

[0095] like Figure 2 As shown, based on Example 1, during the simulated charging process, the simulated charging system not only needs to have a stable charging current, but also needs to accurately switch the charging mode of the lithium battery under the condition of having a stable charging current, so as to realize the complete simulated charging process of the lithium battery. The simulated charging system for testing a lithium battery chip according to the embodiment of the present invention includes: (voltage stable and current reduced)

[0096] Switching monitoring module: after adjusting the charging current, the charging voltage of the lithium battery is monitored in real time, and the identification signal is obtained by processing and analyzing. Based on the generation time point of the identification signal and the expected generation time point of the constant voltage conversion point, the monitoring and analysis period is obtained. Based on the processing and analysis of the charging current of the simulated charging system and the charging voltage of the lithium battery during the monitoring and analysis period, the switching risk value of the simulated charging system is obtained.

[0097] It should be noted that the constant voltage conversion point represents the voltage critical point at which the simulated charging system switches from the constant current charging mode to the constant voltage charging mode (the constant voltage conversion point of the lithium battery is 4.2V), and the expected generation time of the constant voltage conversion point represents the expected time when the lithium battery charging voltage reaches the constant voltage conversion point. The expected generation time of the constant voltage conversion point is obtained according to the charging guide or charging use regulations during the production design of the lithium battery. In the charging regulations of the lithium battery, i.e. the charging guide, various charging parameters of the lithium battery are specified, as well as the time when the charging voltage of the lithium battery reaches the constant voltage conversion point under various charging parameters, which is the expected generation time of the constant voltage conversion point.

[0098] In some embodiments, the charging voltage of the lithium battery is monitored in real time, and the difference between the charging voltage and the constant voltage conversion point is processed to obtain a voltage proximity value, and the voltage proximity value is compared with a voltage proximity threshold value:

[0099] If the voltage proximity value is greater than or equal to the voltage proximity threshold, an identification signal is generated;

[0100] If the voltage approach value is less than the voltage approach threshold, the real-time monitoring of the lithium battery charging voltage continues;

[0101] It should be noted that the voltage approaching threshold and the current approaching threshold are both empirical values, which are set by staff based on experience. In the process of simulated charging, in order to prevent abnormal problems in the simulation system when the charging voltage is close to the constant voltage conversion point, causing the charging voltage to exceed the constant voltage conversion point, the staff usually sets the voltage approaching threshold. When the charging voltage is close to the constant voltage conversion point, advance processing and analysis are performed to prevent the charging voltage from exceeding the constant voltage conversion point and causing damage to the lithium battery.

[0102] Based on the identification signal, marking a period between a generation time point of the identification signal and an expected generation time point of the constant voltage conversion point as a monitoring and analysis period;

[0103] The monitoring and analysis period is divided into several monitoring and analysis sub-periods, and the charging current of the simulation system and the charging voltage of the lithium battery in the sub-period are monitored in real time. The coordinate system is constructed with time as the X-axis and voltage as the Y-axis, and the charging voltage in the monitoring and analysis sub-period is marked and connected in the coordinate system to construct a charging voltage change curve in the monitoring and analysis sub-period. The charging current change curve in the monitoring and analysis sub-period is constructed and obtained in the same way as the construction and acquisition method of the charging voltage change curve;

[0104] Divide the charging voltage variation curve into several voltage sub-curves, obtain the slope of each voltage sub-curve segment, and integrate them into a slope data group, obtain the variance value of the slope data group, and mark it as FC;

[0105] Similarly, the charging current change curve is divided into several current sub-curves, the slope of each current sub-curve is obtained, and the current sub-curve is marked according to the positive or negative slope of the current sub-curve, specifically:

[0106] If the slope of the current sub-curve is positive, its current sub-curve is marked as a growth sub-curve;

[0107] If the slope of the current sub-curve is negative, its current sub-curve is marked as a descending sub-curve;

[0108] Count the number of decreasing sub-curves and compare it with the number of all current sub-curves to obtain the current decreasing ratio, which is marked as XJ;

[0109] The obtained variance value FC of the slope data set and the current drop ratio XJ are processed by the formula: The switching state value QH is obtained, wherein a1 and a2 are both preset proportional coefficients;

[0110] The switching state value is compared with the switching state threshold, and its monitoring and analysis sub-period is marked, specifically:

[0111] If the switching state value QH is greater than or equal to the switching state threshold, the monitoring and analysis sub-period is marked as a suspected waiting switching period;

[0112] If the switching state value QH is less than the switching state threshold, the monitoring and analysis sub-period is marked as a non-suspected waiting switching period;

[0113] If the monitoring and analysis sub-period is marked as a suspected waiting-for-switching period, the charging current at the beginning and the charging current at the end of the suspected waiting-for-switching period are obtained, and the difference is processed to obtain the charging current change difference;

[0114] If the charging current change difference is positive, it means that the charging current in the suspected waiting-for-switching period is on an upward trend as a whole, and the suspected waiting-for-switching period is marked as a non-waiting-for-switching period;

[0115] If the charging current variation is poor, it means that the charging current in the suspected waiting-to-switch period is on a downward trend as a whole, and the suspected waiting-to-switch period is marked as the waiting-to-switch period;

[0116] It should be noted that the meaning of the period to be switched is: in the period to be switched, the variance value FC of the slope data group is small and the current drop ratio XJ is large, and the charging current is generally on a downward trend, wherein the variance value FC of the data group reflects the change of the charging voltage in the period to be switched, and the smaller the variance value, the smaller the fluctuation of the charging voltage change in the period to be switched, and the stable charging voltage, and the current drop ratio XJ reflects the overall decline of the current in the period to be switched, and the larger the current drop ratio XJ, the overall decline in the period to be switched, and the charging current is generally on a downward trend, which meets the state conditions of constant voltage switching, specifically: in actual charging, when the charging voltage of the lithium battery is close to the constant voltage conversion point, its charging voltage will gradually stabilize, and at the same time, the simulation charging system will gradually reduce the voltage to prevent the charging voltage from changing rapidly beyond the constant voltage conversion point;

[0117] If the waiting switching period is detected in real time, the interval between the waiting switching period and the last monitoring and analysis sub-period is obtained, and the interval is processed by comparing it with the duration corresponding to the monitoring and analysis period to obtain the switching risk value;

[0118] If the waiting switching period or non-suspected waiting switching period is not monitored in real time, the next monitoring and analysis sub-period will continue to be monitored, and during the monitoring process, the number of remaining monitoring and analysis sub-periods that have not been monitored will be counted in real time, and the number of monitoring and analysis sub-periods will be multiplied by the length of the monitoring and analysis sub-periods to obtain the remaining detection time, and the remaining monitoring time will be ratioed with the length of the monitoring and analysis period to obtain the switching risk value;

[0119] It should be noted that the switching risk value means: when the monitoring identifies the waiting switching period, the interval between the waiting switching period and the constant voltage conversion point is analyzed. The shorter the interval, the later the simulated charging system enters the waiting switching state, which means that the risk of not being able to switch the charging mode in time when the charging voltage reaches the constant voltage conversion point is higher. When the waiting switching period is not detected, the total duration (remaining detection time) corresponding to the remaining monitoring analysis sub-periods is analyzed. The shorter the total duration, the simulated charging system not only has not entered the waiting switching state, but also has little time left for the charging voltage to reach the constant voltage conversion point, which means that the risk of not being able to switch the charging mode in time when the charging voltage reaches the constant voltage conversion point is higher.

[0120] Switching control module: judging whether to stop the simulation system to simulate charging of the lithium battery according to the switching risk value;

[0121] Specifically, the switching risk value is compared with the switching risk threshold:

[0122] If the switching risk value is greater than or equal to the switching risk threshold, the simulation system is stopped to simulate charging the lithium battery;

[0123] If the switching risk value is less than the switching risk threshold, no processing is performed;

[0124] If the simulation system is stopped to simulate charging of the lithium battery, it is necessary to perform abnormal detection on the simulation system, including but not limited to:

[0125] System setting test: Check the settings of the simulation system to confirm whether the voltage value of the constant voltage conversion point and the triggering conditions of the constant voltage charging mode have been set correctly.

[0126] Sensor detection: Check whether the sensor used to detect the battery charging voltage is working properly and whether there is any reading error or failure.

[0127] Control logic detection: Analyze the control logic of the simulation system to confirm whether the constant voltage mode charging signal should be triggered when the charging voltage reaches the constant voltage conversion point, and check whether the relevant control logic is correct.

[0128] Software or hardware detection: Consider whether there is a software bug or hardware failure that causes the system to be unable to correctly generate or transmit the constant voltage mode charging signal.

[0129] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A simulated charging system for testing lithium battery chips, characterized by: include: Constant current charging analysis module: During the simulated charging cycle, the charging current of the simulated charging system is monitored in real time when the lithium battery chip is charged with constant current. The charging current is processed and analyzed to obtain an analysis signal. The current deviation period is obtained based on the generation time of the analysis signal. A current change curve is constructed based on the charging current during the current deviation period. The current change curve is processed and analyzed to obtain the sharp change value. The analysis signal is generated as follows: Real-time monitoring of the charging current of the simulated charging system. When the charging current of the simulated charging system deviates from the preset constant current during constant current charging, the charging current of the simulated charging system is subtracted from the nearest constant current range endpoint value, and the absolute value of the difference is taken to obtain the charging current difference. The charging current difference is then ratioed with the nearest constant current range endpoint value to obtain the current approximate value. comparing the current proximity value with a current proximity threshold; If the current approaching value is greater than or equal to the current approaching threshold, an analysis signal is generated, wherein the current approaching threshold is an empirical value set based on the experience of the staff. The current approaching threshold is a warning value set to prevent the charging current from exceeding the constant current range due to fluctuations when the simulation system simulates charging of the lithium battery; The current deviation period is obtained as follows: Based on the analysis signal, marking the period between the time when the charging current deviates from the preset constant current and the time when the analysis signal is generated as a current deviation period; The method for obtaining the sharp change value is: The time deviation value Sjz and the deviation duration value CXz are processed by the formula: The sharp change value Jz is obtained, where s1 and s2 are both preset proportional coefficients; The time deviation value Sjz is obtained as follows: According to the start and end time points of the current deviation period, the duration of the current deviation period is extracted, and the duration is compared with the duration of the simulated charging cycle to obtain a time deviation value, which is marked as Sjz; The deviation duration value CXz is obtained as follows: Obtain the charging current during the current deviation period, construct a two-dimensional coordinate system with the charging current as the Y-axis and time as the X-axis, mark the charging current during the current deviation period in the coordinate system, and connect the marked charging current data points to obtain a current change curve; Divide the current deviation period into a number of deviation sub-periods of equal length, obtain a portion of the current change curve corresponding to each deviation sub-period, and mark it as a current change sub-curve segment; Measure the slope value of the current change sub-curve segment, and perform positive and negative identification and comparison between the slope value of the current change sub-curve segment and the reference slope value. The specific identification and comparison process is as follows: If the slope value of the current change sub-curve segment has the same sign as the reference slope value, the current change sub-curve segment is marked as a same-direction sub-curve segment; If the slope value of the current change sub-curve segment is different from the positive and negative corresponding to the reference slope value, then the current change sub-curve segment is marked as a non-codirectional sub-curve segment; The reference slope value is obtained by connecting the two end points of the current change curve with a straight line to obtain the slope value of the connecting line of the end points of the current change curve, which is the reference slope value; Count the number of sub-curve segments in the same direction and compare it with the number of all current change sub-curve segments to obtain the deviation duration value, which is marked as CXz; Constant current charging identification module: determines whether the charging current changes sharply during constant current charging based on the sharp change value. If so, it generates an adjustment signal; The adjustment signal is generated as follows: The sharp change value is compared with the sharp change threshold. The specific comparison process is as follows: If the sharp change value is greater than or equal to the sharp change threshold, it means that the charging current changes sharply during constant current charging, and an adjustment signal is generated; Constant current charging adjustment module: Based on the adjustment signal, the charging current when the analysis signal is generated is processed to obtain a voltage control value, and the charging voltage of the simulated charging system is adjusted according to the voltage control value to achieve charging current adjustment; The specific process of obtaining the voltage control value based on the adjustment signal and the charging current when the analysis signal is generated is as follows: Obtaining the charging current of the simulated charging system when the analysis signal is generated, performing subtraction processing on the current and the preset constant current to obtain a deviation current value, and multiplying the deviation current value by the charging resistance of the simulated charging system to obtain a voltage control value; Switching monitoring module: After adjusting the charging current, the charging voltage of the lithium battery is monitored in real time, and an identification signal is obtained through processing and analysis. The monitoring and analysis period is determined based on the generation time of the identification signal and the expected generation time of the constant voltage transition point. The switching risk value of the simulated charging system is obtained by processing and analyzing the charging current of the simulated charging system and the charging voltage of the lithium battery during the monitoring and analysis period. The period between the generation time point of the identification signal and the expected generation time point of the constant voltage conversion point is marked as the monitoring and analysis period. The expected generation time point of the constant voltage conversion point represents the expected time when the charging voltage of the lithium battery reaches the constant voltage conversion point. The expected generation time point of the constant voltage conversion point is obtained based on the charging guide or charging use regulations during the production and design of the lithium battery. The charging regulations of the lithium battery, i.e., the charging guide, specify various charging parameters of the lithium battery, as well as the time when the charging voltage of the lithium battery reaches the constant voltage conversion point under various charging parameters, which is the expected generation time point of the constant voltage conversion point. The identification signal is obtained in the following manner: The charging voltage of the lithium battery is monitored in real time, and the difference between it and the constant voltage conversion point is processed to obtain the voltage approach value, which is then compared with the voltage approach threshold value: If the voltage proximity value is greater than or equal to the voltage proximity threshold, an identification signal is generated; If the voltage approach value is less than the voltage approach threshold, the real-time monitoring of the lithium battery charging voltage will continue. The voltage approach threshold and the current approach threshold are both empirical values ​​set by the staff based on experience. During the simulated charging process, in order to prevent abnormal problems in the simulation system when the charging voltage is close to the constant voltage conversion point, causing the charging voltage to exceed the constant voltage conversion point, the staff will usually set a voltage approach threshold. When the charging voltage is close to the constant voltage conversion point, advance processing and analysis will be performed to prevent the charging voltage from exceeding the constant voltage conversion point and causing damage to the lithium battery. The switching risk value is obtained in the following manner: The switching state value QH is compared with the switching state threshold, and its monitoring and analysis sub-period is marked, specifically: If the switching state value QH is greater than or equal to the switching state threshold, the monitoring and analysis sub-period is marked as a suspected waiting switching period; If the switching state value QH is less than the switching state threshold, the monitoring and analysis sub-period is marked as a non-suspected waiting switching period; If the monitoring and analysis sub-period is marked as a suspected waiting-for-switching period, the charging current at the beginning and the charging current at the end of the suspected waiting-for-switching period are obtained, and the difference is processed to obtain the charging current change difference; If the charging current change difference is positive, it means that the charging current in the suspected switching period is on an upward trend as a whole, and the suspected switching period is marked as a non-switching period; If the charging current variation is poor, it means that the charging current in the suspected waiting-for-switching period is on a downward trend as a whole, and the suspected waiting-for-switching period is marked as the waiting-for-switching period; If a waiting switching period is detected in real-time monitoring, the interval between the waiting switching period and the last monitoring and analysis sub-period is obtained, and the interval is compared with the duration corresponding to the monitoring and analysis period to obtain the switching risk value; If no waiting switching period or non-suspected waiting switching period is detected in real time, the next monitoring and analysis sub-period will continue to be monitored. During the monitoring process, the number of remaining unmonitored monitoring and analysis sub-periods will be counted in real time. The number of monitoring and analysis sub-periods will be multiplied by the duration of the monitoring and analysis sub-period to obtain the remaining detection time. The remaining monitoring time will be ratioed with the duration corresponding to the monitoring and analysis period to obtain the switching risk value. The switching state value QH is obtained as follows: The variance value FC of the slope data group and the current drop ratio XJ are processed by the formula: Obtain the switching state value QH, where a1 and a2 are both preset proportional coefficients; The variance value FC of the slope data set is obtained as follows: The monitoring and analysis period is divided into several monitoring and analysis sub-periods, and the charging current of the simulation system and the charging voltage of the lithium battery in the sub-period are monitored and analyzed in real time. The coordinate system is constructed with time as the X-axis and voltage as the Y-axis. The charging voltages in the monitoring and analysis sub-periods are marked and connected in the coordinate system to construct a charging voltage change curve in the monitoring and analysis sub-period. The charging current change curve in the monitoring and analysis sub-period is constructed and obtained in the same way as the charging voltage change curve; Divide the charging voltage change curve into several voltage sub-curves, obtain the slope of each voltage sub-curve segment, and integrate them into a slope data group, obtain the variance value of the slope data group, and mark it as FC; The current drop ratio XJ is obtained as follows: The charging current change curve is divided into several current sub-curves, the slope of each current sub-curve is obtained, and the current sub-curve is marked according to the positive or negative slope of the current sub-curve, specifically: If the slope of the current sub-curve is positive, its current sub-curve is marked as a growth sub-curve; If the slope of the current sub-curve is negative, its current sub-curve is marked as a descending sub-curve; Count the number of decreasing sub-curves and compare it with the number of all current sub-curves to obtain the current decreasing ratio, which is marked as XJ; Switching control module: determines whether to stop the simulation system to simulate charging of the lithium battery according to the switching risk value.

2. The lithium battery chip testing simulation charging system according to claim 1, characterized in that: The process of determining whether to stop the simulation system from simulating charging of the lithium battery is as follows: Compare the switching risk value to the switching risk threshold: If the switching risk value is greater than or equal to the switching risk threshold, the simulation system is stopped to simulate charging the lithium battery.

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