A method, apparatus, and storage medium for defining the stepped charging process of a pouch battery.

Abstract

This application provides a method, apparatus, and storage medium for determining the stepped charging steps of a pouch battery. The method includes: detecting the thickness change caused by cell expansion during the charging process of a first battery under test at different charging rates; determining a first curve of the first battery under test at different charging rates; determining a target interval for dividing the gradient based on the rising and falling trends of the first curves corresponding to different charging rates in the first curves; using the maximum capacity within the target interval as the target capacity; determining the thickness change and corresponding charging rate of the first curve at the target capacity; establishing a second curve based on the thickness change and charging rate; and using the charging rate corresponding to the inflection point where the slope of the second curve changes greater than a first fluctuation threshold as the target charging rate for the target interval during the charging process. This application can efficiently determine the gradient of stepped charging and the charging rate adapted to each gradient.

Description

Technical Field

[0001] This application relates to the field of battery testing technology, and in particular to a method, apparatus and storage medium for determining the stepped charging process of a pouch battery. Background Technology

[0002] Proper use of batteries can not only fully utilize their electrochemical performance but also reduce temperature rise, slow down wear and tear, and extend their lifespan. Currently, battery charging mainly uses constant current and constant voltage charging. However, according to Musk's three laws, as charging time progresses, the current required by the battery will decrease. At this point, charging the battery with a fixed current will result in a current greater than the actual charging current needed by the battery, which will exacerbate internal polarization, deteriorate the internal environment of the battery, and affect its lifespan. Therefore, stepped charging is far more effective than constant current and constant voltage charging.

[0003] Stepped charging, also known as segmented constant current charging, can make the actual charging current curve of the battery close to the acceptable charging current curve, and is an effective method for achieving fast battery charging. Existing stepped charging methods use the capacity gradient method, employing the capacity gradient parameter dU / dC as the criterion for terminating a stage of constant current charging. The charging termination capacity gradient parameter is determined according to the constant current charging characteristic curve of the battery type. During charging, the controller samples the charging voltage at a set frequency, calculates the capacity gradient value under I(n), and compares it with the set charging termination capacity gradient criterion. Based on the comparison result, it determines whether to terminate the current stage of constant current charging. The calculation process for defining the stepped charging steps using this method is relatively complex, and existing technologies lack efficient solutions for specifying stepped charging steps. Summary of the Invention

[0004] In view of this, embodiments of this application provide a method, apparatus, electronic device, and storage medium for determining the step-by-step charging process of a pouch battery, which can efficiently determine the gradient of the step-by-step charging and the rate of return suitable for each gradient.

[0005] The technical solution of this application embodiment is implemented as follows:

[0006] In a first aspect, embodiments of this application provide a method for determining the stepped charging process steps for a pouch battery, comprising the following steps:

[0007] Select any soft-pack battery from the same batch and model as the first test battery, charge the first test battery at different rates, and record the first thickness change value of the first test battery cell expansion and the capacity of the first test battery during the charging process.

[0008] Based on the first thickness change value and the capacity of the first battery under test at different rates, a first curve is determined, wherein the first horizontal axis of the first curve represents the capacity, the first vertical axis of the first curve represents the first thickness change value, and the charging process of the first battery under test at each rate corresponds to a first curve in the first curve.

[0009] Based on the rising and falling trend of the first curve, at least one target interval is determined from the horizontal axis of the first curve graph, and the maximum value of the capacity in the target interval is taken as the target capacity. Based on the second thickness change value corresponding to the target capacity in the first curve and the multiplier of the first curve corresponding to the target capacity, a second curve graph is determined, wherein the second horizontal axis of the second curve graph represents the multiplier, and the second vertical axis of the second curve graph represents the second thickness change value.

[0010] Based on the slope of the second curve in the second curve graph, the turning point where the slope change is greater than the first fluctuation threshold is determined, and the multiplier corresponding to the turning point on the second horizontal axis is taken as the target charging multiplier of the target range during the charging process.

[0011] In one possible implementation, recording the first thickness change value of the first battery cell under test during charging includes:

[0012] The negative terminal of the first battery under test is fixed, and the height change value of the plane where the positive terminal of the first battery under test is located during the charging process is detected by a displacement sensor, and the height change value is used as the first thickness change value.

[0013] In one possible implementation, determining at least one target interval from the horizontal axis of the first curve graph based on the rising and falling trend of the first curve includes:

[0014] Determine the first starting point of each first curve, the first inflection point that appears from the first starting point, and the capacity corresponding to the inflection point on the first horizontal axis;

[0015] The average of the capacity is taken as the interval endpoint, and the interval from the second starting point on the horizontal axis to the interval endpoint is taken as a target interval.

[0016] The first inflection point in each first curve is updated to the first starting point, and the endpoint of the interval is updated to the second starting point.

[0017] In one possible implementation, after determining the second graph, the method further includes:

[0018] At least one soft-pack battery of the same model from the same batch is selected as a comparison battery, and the third curve of the comparison battery in the second curve is determined.

[0019] The third curve and the second curve are fitted together, and the fitted result is used as the second curve.

[0020] In one possible implementation, after determining the first graph, the method further includes:

[0021] The first curve in the first curve graph is smoothed to remove points in the first curve whose fluctuation amplitude is greater than the second fluctuation threshold.

[0022] After determining the second curve, the method further includes:

[0023] The second curve in the second curve graph is smoothed to remove points in the second curve whose fluctuation amplitude is greater than the third fluctuation threshold.

[0024] In one possible implementation, the method further includes:

[0025] Select at least one pouch cell from the same batch and model of pouch cells as the second test cell;

[0026] For the first battery under test, the first battery under test is charged in the target range using the target charging rate that matches the target range, and the first charging result is recorded. For the second battery under test, the second battery under test is charged in the constant current charging mode, and the second charging result is recorded.

[0027] The first charging result and the second charging result are compared and verified.

[0028] In one possible implementation, recording the first charging result includes:

[0029] A first coordinate system is established with the capacity of the first or second battery under test as the horizontal axis and the third thickness change value of the cell expansion during the charging process of the first or second battery under test as the vertical axis. A second coordinate system is established with the capacity of the first or second battery under test as the horizontal axis and the temperature change value of the first or second battery under test during the charging process as the vertical axis.

[0030] A first verification curve is determined in the first coordinate system to describe the cell expansion change of the first battery under test during charging, and a second verification curve is determined in the second coordinate system to describe the temperature change of the first battery under test during charging.

[0031] The recording of the second charging result includes:

[0032] A third verification curve is determined in the first coordinate system to describe the cell expansion change of the second battery under test during charging, and a fourth verification curve is determined in the second coordinate system to describe the temperature change of the second battery under test during charging.

[0033] The comparison and verification of the first charging result and the second charging result includes:

[0034] Based on the first and third verification curves in the first coordinate system, the cell expansion change of the first battery under test during charging is verified. Based on the second and fourth verification curves in the second coordinate system, the temperature change of the battery under test during charging is verified.

[0035] Secondly, embodiments of this application also provide a device for determining the tiered charging steps for a soft-pack battery, the device comprising:

[0036] The detection module is used to select any one soft-pack battery from the same batch and model of soft-pack batteries as the first test battery, charge the first test battery at different rates, and record the first thickness change value of the cell expansion of the first test battery and the capacity of the first test battery during the charging process.

[0037] The first determining module is used to determine a first curve based on the first thickness change value and the capacity of the first battery under test at different rates, wherein the first horizontal axis of the first curve represents the capacity, the first vertical axis of the first curve represents the first thickness change value, and the charging process of the first battery under test at each rate corresponds to a first curve in the first curve.

[0038] The second determining module is used to determine at least one target interval from the horizontal axis of the first curve graph according to the rising and falling trend of the first curve, and take the maximum value of the capacity in the target interval as the target capacity, and determine the second curve graph according to the second thickness change value corresponding to the target capacity in the first curve and the multiplier of the first curve corresponding to the target capacity, wherein the second horizontal axis of the second curve graph represents the multiplier, and the second vertical axis of the second curve graph represents the second thickness change value;

[0039] The third determining module is used to determine the turning point where the slope change is greater than the first fluctuation threshold based on the slope of the second curve in the second curve graph, and to take the multiplier corresponding to the turning point on the second horizontal axis as the target charging multiplier of the target range during the charging process.

[0040] Thirdly, embodiments of this application also provide an electronic device, including: a processor, a storage medium, and a bus, wherein the storage medium stores machine-readable instructions executable by the processor, and when the electronic device is running, the processor communicates with the storage medium via the bus, and the processor executes the machine-readable instructions to perform the steps of the method for determining the stepped charging process of a pouch battery as described in any of the first aspects.

[0041] Fourthly, embodiments of this application also provide a computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, performs the steps of the method for determining the stepped charging process of a pouch battery as described in any one of the first aspects.

[0042] The embodiments of this application have the following beneficial effects:

[0043] By detecting the thickness change caused by cell expansion during the charging process of the first battery under test at different rates, a first curve of the first battery under test at different rates is determined. Based on the rising and falling trends of the first curve corresponding to different rates in the first curve, a target interval for dividing the gradient is determined. On this basis, the maximum capacity in the target interval is taken as the target capacity, and the thickness change and corresponding rate corresponding to the first curve at the target capacity are determined. Based on the thickness change and rate, a second curve is established. The rate corresponding to the inflection point where the slope change of the second curve is greater than the first fluctuation threshold is taken as the target charging rate of the target interval during the charging process. The target charging rate of the target interval determined in this way reflects the maximum rate that the target interval is adapted to to a certain extent. Therefore, the gradient of stepped charging and the charging rate adapted to each gradient can be determined more efficiently. Attached Figure Description

[0044] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 This is a flowchart illustrating steps S101-S104 provided in the embodiments of this application;

[0046] Figure 2 This is a flowchart illustrating steps S201-S203 provided in the embodiments of this application;

[0047] Figure 3This is a flowchart illustrating steps S301-S302 provided in the embodiments of this application;

[0048] Figure 4 This is a flowchart illustrating steps S401-S403 provided in the embodiments of this application;

[0049] Figure 5 This is the first graph provided in the embodiments of this application;

[0050] Figure 6 This is a second graph of the 0-30% target range provided in the embodiments of this application;

[0051] Figure 7 This is a second graph showing the target range of 30%-60% provided in the embodiments of this application;

[0052] Figure 8 This is a second graph showing the target range of 60%-100% provided in the embodiments of this application;

[0053] Figure 9 This is a comparison chart of the first charging results provided in an embodiment of this application;

[0054] Figure 10 This is a comparison chart of the second charging results provided in an embodiment of this application;

[0055] Figure 11 This is a schematic diagram of the structure of the step-by-step charging device for soft-pack batteries provided in the embodiments of this application;

[0056] Figure 12 This is a schematic diagram of the composition structure of the electronic device provided in the embodiments of this application. Detailed Implementation

[0057] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the accompanying drawings in this application are for illustrative and descriptive purposes only and are not intended to limit the scope of protection of this application. Furthermore, it should be understood that the schematic drawings are not drawn to scale. The flowcharts used in this application illustrate operations implemented according to some embodiments of this application. It should be understood that the operations in the flowcharts may not be implemented in sequence, and steps without logical contextual relationships may be reversed or implemented simultaneously. In addition, those skilled in the art, guided by the content of this application, may add one or more other operations to the flowcharts, or remove one or more operations from the flowcharts.

[0058] In the following description, references are made to “some embodiments,” which describe a subset of all possible embodiments. However, it is understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0059] Furthermore, the described embodiments are merely some, not all, of the embodiments of this application. The components of the embodiments of this application described and illustrated herein can typically be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0060] In the following description, the terms "first, second, third" are used merely to distinguish similar objects and do not represent a specific ordering of objects. It is understood that "first, second, third" may be interchanged in a specific order or sequence where permitted, so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein.

[0061] It should be noted that the term "comprising" will be used in the embodiments of this application to indicate the presence of the features declared thereafter, but does not exclude the addition of other features.

[0062] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application and is not intended to limit this application.

[0063] See Figure 1 , Figure 1 This is a flowchart illustrating steps S101-S104 of the method for determining the stepped charging process of a soft-pack battery provided in this application embodiment. Figure 1 Steps S101-S104 are explained below.

[0064] Step S101: Select any soft-pack battery from the same batch and model of soft-pack batteries as the first test battery, charge the first test battery at different rates, and record the first thickness change value of the first test battery cell expansion and the capacity of the first test battery during the charging process.

[0065] Step S102: Based on the first thickness change value and the capacity of the first battery under test at different rates, determine a first curve, wherein the first horizontal axis of the first curve represents the capacity, the first vertical axis of the first curve represents the first thickness change value, and the charging process of the first battery under test at each rate corresponds to a first curve in the first curve.

[0066] Step S103: Based on the rising and falling trend of the first curve, at least one target interval is determined from the horizontal axis of the first curve graph, and the maximum value of the capacity in the target interval is taken as the target capacity. Based on the second thickness change value corresponding to the target capacity in the first curve and the multiplier of the first curve corresponding to the target capacity, a second curve graph is determined, wherein the second horizontal axis of the second curve graph represents the multiplier, and the second vertical axis of the second curve graph represents the second thickness change value.

[0067] Step S104: Based on the slope of the second curve in the second curve graph, determine the turning point where the slope change is greater than the first fluctuation threshold, and take the multiplier corresponding to the turning point on the second horizontal axis as the target charging multiplier of the target range during the charging process.

[0068] The aforementioned method for determining the stepped charging process for pouch batteries involves detecting the thickness change caused by cell expansion during the charging process of the first battery under test at different rates. This determines the first curve of the first battery under test at different rates. Based on the rising and falling trends of the first curve at different rates, a target interval for dividing the gradient is determined. On this basis, the maximum capacity in the target interval is taken as the target capacity. The thickness change and corresponding rate of the first curve at the target capacity are determined. Based on the thickness change and rate, a second curve is established. The rate corresponding to the inflection point where the slope of the second curve changes more than the first fluctuation threshold is taken as the target charging rate of the target interval during the charging process. The target charging rate of the target interval determined in this way reflects the maximum rate that the target interval is adapted to to a certain extent. Therefore, the gradient of stepped charging and the current adapted to each gradient can be determined more efficiently.

[0069] The exemplary steps described above in the embodiments of this application will be explained below.

[0070] In step S101, any soft-pack battery of the same model from the same batch is selected as the first test battery. The first test battery is charged at different rates, and the first thickness change value of the cell expansion of the first test battery and the capacity of the first test battery are recorded during the charging process.

[0071] Here, the pouch battery can be any structure (pouch and aluminum shell) and any stacking method (laminated and wound). Taking lithium iron phosphate battery as an example, any lithium iron phosphate battery of the same model from the same batch is selected as the first battery to be tested. The first battery to be tested is charged at different rates, and the first thickness change value of the cell expansion of the first battery to be tested and the capacity (SOC) of the first battery to be tested are recorded during the charging process.

[0072] It should be noted that different rates can be arbitrary. In this embodiment, eleven rates of 0.1C, 0.2C, 0.5C, 0.8C, 1C, 1.1C, 1.2C, 1.3C, 1.4C, 1.5C, and 1.6C are selected to test the first-generation test battery. Here, C is used to represent the battery charge-discharge capacity rate.

[0073] In some embodiments, recording the first thickness change value of the first battery cell under test during charging includes:

[0074] The negative terminal of the first battery under test is fixed, and the height change value of the plane where the positive terminal of the first battery under test is located during the charging process is detected by a displacement sensor, and the height change value is used as the first thickness change value.

[0075] Here, because the lithium iron phosphate battery cell expands during charging, causing the height of the pouch battery to increase, after fixing the negative electrode of the first-generation test battery, the height change value of the plane where the positive electrode of the first test battery is located during charging can be detected by a high-precision displacement sensor, and the data detected by the high-precision displacement sensor is used as the first thickness change value, which reflects the expansion height of the first test battery cell.

[0076] In step S102, a first curve is determined based on the first thickness change value and the capacity of the first battery under test at different rates. The first horizontal axis of the first curve represents the capacity, the first vertical axis of the first curve represents the first thickness change value, and the charging process of the first battery under test at each rate corresponds to a first curve in the first curve.

[0077] For example, see Figure 5 , Figure 5 This is the first graph provided in the embodiments of this application. The horizontal axis (X-axis) of the first graph represents the state of charge (SOC), that is, the charge quantity, in %. The vertical axis (X-axis) represents the first thickness change value. ΔS), the unit is mm. In the above embodiments, the charging process of the first battery under test at rates of 0.1C, 0.2C, 0.5C, 0.8C, 1C, 1.1C, 1.2C, 1.3C, 1.4C, 1.5C, and 1.6C corresponds to the first curve 501, first curve 502, first curve 503, first curve 504, first curve 505, first curve 506, first curve 507, first curve 508, first curve 509, first curve 510, and first curve 511 in the figure, respectively.

[0078] In step S103, based on the rising and falling trend of the first curve, at least one target interval is determined from the horizontal axis of the first curve graph, and the maximum value of the capacity in the target interval is taken as the target capacity. Based on the second thickness change value corresponding to the target capacity in the first curve and the multiplier of the first curve corresponding to the target capacity, a second curve graph is determined, wherein the second horizontal axis of the second curve graph represents the multiplier, and the second vertical axis of the second curve graph represents the second thickness change value.

[0079] In some embodiments, see continue to see Figure 5 , Figure 5 The eleven first curves shown have similar rising and falling trends, all of which are a process of rising-falling-rising. Each rising or falling process can be regarded as a charging stage. During the charging process, the eleven first curves begin to fall when the horizontal axis is about 30%. Therefore, 0-30% can be regarded as the first charging stage, that is, the first target range. The eleven first curves begin to rise when the horizontal axis is about 60%. Therefore, 30%-60% can be regarded as the second target range. Finally, 60%-100% can be regarded as the third target range.

[0080] In some embodiments, see Figure 2 , Figure 2 This is a flowchart illustrating steps S201-S203 provided in this application embodiment. Although the corresponding charging stage can be estimated from the rising and falling trend of the first curve, to improve accuracy, the step of determining at least one target interval from the horizontal axis of the first curve graph based on the rising and falling trend of the first curve can be achieved through... Figure 2 The implementation of steps S201-S203 shown will be explained in conjunction with specific steps.

[0081] In step 201, the first starting point of each first curve, the first inflection point appearing from the first starting point, and the capacity corresponding to the inflection point on the first horizontal axis are determined.

[0082] For example, see Figure 5The first curves 501 to 511 have the same first starting point, namely the origin. Starting from the origin, the first inflection points of the first curves 501 to 511 and the corresponding x-coordinates of these inflection points are determined.

[0083] In step 202, the average of the capacity is taken as the interval endpoint, and the interval from the second starting point on the horizontal axis to the interval endpoint is taken as a target interval.

[0084] Here, by averaging the capacity of the horizontal coordinates corresponding to the inflection points mentioned above, we can obtain the capacity of the interval endpoints. Taking the first curve 501 to 503 as an example, the capacity corresponding to the first curve 501 is 28%, the capacity corresponding to the first curve 502 is 32%, and the capacity corresponding to the third curve 503 is 30%. The final average result is 30%. Therefore, 30% is the interval endpoint. Then, the interval from the second starting point (origin) on the horizontal axis to 30% is taken as a target interval.

[0085] It should be noted that although the first starting point and the second starting point in the above embodiments of this application are both the origin, the first starting point represents the starting point of the first curve. However, in the above embodiments, the starting points of the first curves 501 to 511 intersect at the origin. As for the second starting point, it represents the starting point on the horizontal axis. The starting point of the first target interval starts from the origin.

[0086] In step 203, the first inflection point in each first curve is updated to the first starting point, and the interval endpoints are updated to the second starting point.

[0087] Here, after determining the endpoints of the interval and the first target interval, the first inflection point of the first curve 501-511 can be taken as the first starting point. Starting from the first starting point of each of the first curves 501-511, we search backward for the first inflection point (approximately 60%). At the same time, we update 30% as the second starting point, which serves as the start of the next target interval.

[0088] In some embodiments, after determining the target range, it is also necessary to determine the appropriate charging rate for each target range. Each target range determined in the above embodiments reflects a complete charging stage to a certain extent. That is, after reaching the next target range during the charging process, the charging rate needs to be adjusted. The appropriate charging rate for each target range is determined by constructing a second curve.

[0089] For example, see Figure 5Using the maximum capacity (30%) in the first target interval as the target capacity, points with an abscissa of 30% are determined in the first curve 501-511. A coordinate system is established with the multiplier on the horizontal axis and the second thickness variation value on the vertical axis. The positions of these points are then determined in the coordinate system. (See [reference]). Figure 6 , Figure 6 This is a second curve graph of the 0-30% target range provided in this application embodiment. The points mentioned above in the second curve graph are points 601, 602, 603, 604, 605, 606, 607, 608, 609, 610, and 611, respectively. The ordinates of points 601 to 611 correspond sequentially to the first thickness change values ​​of the points with abscissa of 30% in the first curves 501 to 511. The abscissas of points 601 to 611 correspond sequentially to the multipliers of the first curves 501 to 511. It should be noted that the second thickness change value is the ordinate value of these points in the first coordinate system (the first thickness change value). Here, for ease of distinction, it is described as the second thickness change value. Connecting points 601 to 611 sequentially forms the second curve A1.

[0090] For the target range of 0-30%, the following is obtained: Figure 6 The second curve showing the 0-30% target range is similarly illustrated in the following diagram. Figure 7 , Figure 8 , Figure 7 This is a second graph showing the target range of 30%-60% provided in the embodiments of this application. Figure 8 This is a second graph of the 60%-100% target range provided in the embodiments of this application.

[0091] In some embodiments, see Figure 3 After determining the second curve, steps S301-S302 can be performed, which will be explained in detail below.

[0092] In step S301, at least one soft-pack battery is selected from the same batch and model of soft-pack batteries as a comparison battery, and the third curve of the comparison battery in the second curve graph is determined.

[0093] In step S302, the third curve and the second curve are fitted together, and the fitted result is used as the second curve.

[0094] To make the obtained second curve more accurate and to provide a comparison for the second curve A1, at least one pouch battery of the same model from the same batch can be selected as a comparison battery, and the third curve of the comparison battery in the second curve can be determined in the same way.

[0095] Taking two comparative batteries as examples, the third curves A2 and A3 of the comparative batteries in the second curve are obtained by referring to the method provided in the above embodiment in the second curve graph. Figure 7 In the diagram, the second curve is B1, while the third curves for the battery are B2 and B3, respectively. Figure 8 In the diagram, the second curve is C1, and the third curves for comparison are C2 and C3.

[0096] exist Figure 6 Since the comparison batteries involved in A2 and A3 are from the same batch and model as the first battery under test in A1, the fluctuation range between A1, A2, and A3 should be within the preset abnormal range. If abnormal curves appear in A1, A2, and A3, they can be visually identified and addressed. The cause of the abnormality could be battery malfunction or operational error. Furthermore, A1, A2, and A3 can be fitted together to form a single curve. Subsequent testing of the fitted curve can improve accuracy and eliminate errors.

[0097] In some embodiments, after determining the first graph, the method further includes:

[0098] The first curve in the first curve graph is smoothed to remove points in the first curve whose fluctuation amplitude is greater than the second fluctuation threshold.

[0099] After determining the second curve, the method further includes:

[0100] The second curve in the second curve graph is smoothed to remove points in the second curve whose fluctuation amplitude is greater than the third fluctuation threshold.

[0101] Here, for the obtained first and second curves, the curves in either the first or second curve can be smoothed to eliminate fluctuations within a preset range. See [link to relevant documentation]. Figure 5 If the fluctuations in region X exceed the preset second fluctuation threshold, the fluctuations can be eliminated after smoothing, forming a smooth curve.

[0102] In step S104, based on the slope of the second curve in the second curve graph, the turning point where the slope change is greater than the first fluctuation threshold is determined, and the multiplier corresponding to the turning point on the second horizontal axis is taken as the target charging multiplier of the target range during the charging process.

[0103] For example, see the second curve chart within the 0-30% target range. Figure 6 , Figure 6The second curve A1 in the diagram starts at point 601 and continues to point 607. Its curve rises steadily, and after point 607, it almost stops rising and remains approximately horizontal. Therefore, the charging rate (1.25C) corresponding to point 607 can be used as the target charging rate within the 0-30% target range. This target charging rate reflects, to some extent, the maximum charging rate within that target range. It should be noted that the first fluctuation threshold in this embodiment can be flexibly set according to the type and requirements of the first-generation test battery.

[0104] Similarly, for the target charging ranges of 30%-60% and 60%-100%, corresponding target charging rates can be found. The target charging rate for the 30%-60% range is approximately 1C, and the target charging rate for the 60%-100% range is approximately 0.8C. Based on this, a tiered charging process can be developed, which involves using the target charging rate that matches the target range within each range.

[0105] In some embodiments, before the application publishes the defined tiered charging steps, it is also necessary to verify the defined tiered charging process. See [link / reference] Figure 4 , Figure 4 This is a flowchart illustrating steps S401-S403 provided in the embodiments of this application, which will be explained in conjunction with specific steps.

[0106] In step S401, at least one pouch cell is selected from the same batch of pouch cells of the same model as the second cell to be tested.

[0107] In step S402, the first battery under test is charged in the target range using the target charging rate that matches the target range, and a first charging result is recorded. The second battery under test is charged in the constant current charging range, and a second charging result is recorded.

[0108] In step S403, the first charging result and the second charging result are compared and verified.

[0109] Here, at least one pouch battery of the same model from the same batch is selected as the second test battery. The second test battery is charged with constant current and constant voltage. The first test battery is charged with the charging steps determined in the above embodiments of this application. The charging results are verified. The charging effect of the charging with the charging steps determined in the above embodiments of this application is compared with the effect of traditional constant current and constant voltage charging.

[0110] In some embodiments, recording the first charging result includes:

[0111] A first coordinate system is established with the capacity of the first or second battery under test as the horizontal axis and the third thickness change value of the cell expansion during the charging process of the first or second battery under test as the vertical axis. A second coordinate system is established with the capacity of the first or second battery under test as the horizontal axis and the temperature change value of the first or second battery under test during the charging process as the vertical axis.

[0112] A first verification curve is determined in the first coordinate system to describe the cell expansion change of the first battery under test during charging, and a second verification curve is determined in the second coordinate system to describe the temperature change of the first battery under test during charging.

[0113] The recording of the second charging result includes:

[0114] A third verification curve is determined in the first coordinate system to describe the cell expansion change of the second battery under test during charging, and a fourth verification curve is determined in the second coordinate system to describe the temperature change of the second battery under test during charging.

[0115] The comparison and verification of the first charging result and the second charging result includes:

[0116] Based on the first and third verification curves in the first coordinate system, the cell expansion change of the first battery under test during charging is verified. Based on the second and fourth verification curves in the second coordinate system, the temperature change of the battery under test during charging is verified.

[0117] For example, see Figure 9 , Figure 9 This is a comparison chart of the first charging results provided in an embodiment of this application. Figure 9Curves 901 and 902 shown in the figure represent the relationship between the third thickness change value of the cell expansion and the capacity (SOC) when the first battery under test is charged using the charging steps determined in the above embodiments of this application. Curves 901 and 902 each represent a first battery under test. Curves 903 and 904 represent the relationship between the third thickness change value of the cell expansion and the capacity (SOC) of the second battery under test during constant voltage and constant current charging at a rate of 0.5C. Curves 905 and 906 represent the relationship between the third thickness change value of the cell expansion and the capacity (SOC) of the second battery under test during constant voltage and constant current charging at a rate of 0.8C. Curves 907 and 908 represent the relationship between the third thickness change value of the cell expansion and the capacity (SOC) of the second battery under test during constant voltage and constant current charging at a rate of 1C. It should be noted that two parallel samples were set for each charging method. The purpose of this is to allow for a direct perception of the problem from the difference in the curves of the two parallel samples when one of the parallel samples fails.

[0118] See Figure 10 , Figure 10 This is a comparison chart of the second charging results provided in an embodiment of this application. In the second charging result comparison chart, the vertical axis represents temperature, used to verify the temperature change under different charging methods. Figure 10 In the diagram, curves 1001 and 1002 represent the results of charging the first battery under test using the charging steps determined in the above embodiments of this application; curves 1003 and 1004 represent the relationship between the temperature and capacity (SOC) of the second battery under test during constant voltage and constant current charging at a rate of 0.5C; curves 1005 and 1006 represent the relationship between the temperature and capacity (SOC) of the second battery under test during constant voltage and constant current charging at a rate of 0.8C; and curves 1007 and 1008 represent the relationship between the temperature and capacity (SOC) of the second battery under test during constant voltage and constant current charging at a rate of 1C.

[0119] Combination Figure 9 and Figure 10The curves in the figure can be compared with the traditional constant voltage and constant current method to show the changes in cell expansion and temperature during charging using the stepped charging steps determined in the embodiments of this application. The results show that, using the stepped charging steps determined in the embodiments of this application, the fluctuation range of the cell expansion curve is similar to that of the traditional method. For the temperature change curve, in the 0-30% target range, the temperature is slightly higher than that of the traditional method, but since a target charging rate of 1.25C is used, which is higher than the maximum rate of 1C in the traditional method, it meets expectations. In the 30%-60% target range, using a target charging rate of 1C, the temperature rises steadily and is similar to the 1C rate in the traditional method. In the 60%-100% target range, using a target charging rate of 0.8C, the temperature begins to drop rapidly and eventually becomes equal to the 0.5C in the traditional method. Therefore, the effect of charging using the stepped charging steps determined in the embodiments of this application is better.

[0120] In summary, the embodiments of this application have the following beneficial effects:

[0121] By detecting the thickness change caused by cell expansion during the charging process of the first battery under test at different rates, a first curve of the first battery under test at different rates is determined. Based on the rising and falling trends of the first curve corresponding to different rates in the first curve, a target interval for dividing the gradient is determined. On this basis, the maximum capacity in the target interval is taken as the target capacity, and the thickness change and corresponding rate corresponding to the first curve at the target capacity are determined. Based on the thickness change and rate, a second curve is established. The rate corresponding to the inflection point where the slope change of the second curve is greater than the first fluctuation threshold is taken as the target charging rate of the target interval during the charging process. The target charging rate of the target interval determined in this way reflects the maximum rate that the target interval is adapted to to a certain extent. Therefore, the gradient of stepped charging and the current adapted to each gradient can be determined more efficiently.

[0122] Based on the same inventive concept, this application also provides a device for determining the step-by-step charging process of a soft-pack battery, which corresponds to the method for determining the step-by-step charging process of a soft-pack battery in the first embodiment. Since the principle of the device in this application is similar to the above-mentioned method for determining the step-by-step charging process of a soft-pack battery, the implementation of the device can refer to the implementation of the method, and the repeated parts will not be described again.

[0123] like Figure 11 As shown, Figure 11 This is a schematic diagram of the structure of the soft-pack battery stepped charging step determination device 1100 provided in this application embodiment. The soft-pack battery stepped charging step determination device 1100 includes:

[0124] The detection module 1101 is used to select any soft-pack battery from the same batch and model of soft-pack batteries as the first test battery, charge the first test battery at different rates, and record the first thickness change value of the cell expansion of the first test battery and the capacity of the first test battery during the charging process.

[0125] The first determining module 1102 is used to determine a first curve based on the first thickness change value and the capacity of the first battery under test at different rates, wherein the first horizontal axis of the first curve represents the capacity, the first vertical axis of the first curve represents the first thickness change value, and the charging process of the first battery under test at each rate corresponds to a first curve in the first curve.

[0126] The second determining module 1103 is used to determine at least one target interval from the horizontal axis of the first curve graph according to the rising and falling trend of the first curve, and take the maximum value of the capacity in the target interval as the target capacity, and determine a second curve graph according to the second thickness change value corresponding to the target capacity in the first curve and the multiplier of the first curve corresponding to the target capacity, wherein the second horizontal axis of the second curve graph represents the multiplier, and the second vertical axis of the second curve graph represents the second thickness change value;

[0127] The third determining module 1104 is used to determine the turning point where the slope change is greater than the first fluctuation threshold based on the slope of the second curve in the second curve graph, and to take the multiplier corresponding to the turning point on the second horizontal axis as the target charging multiplier of the target range during the charging process.

[0128] Those skilled in the art should understand that Figure 11 The functions of each unit in the pouch battery stepped charging step planning device 1100 shown can be understood by referring to the relevant description of the pouch battery stepped charging step planning method described above. Figure 11 The functions of each unit in the pouch battery stepped charging process planning device 1100 shown can be implemented by a program running on a processor or by specific logic circuits.

[0129] In one possible implementation, the detection module 1101 records a first thickness change value during the expansion of the first battery cell under test during charging, including:

[0130] The negative terminal of the first battery under test is fixed, and the height change value of the plane where the positive terminal of the first battery under test is located during the charging process is detected by a displacement sensor, and the height change value is used as the first thickness change value.

[0131] In one possible implementation, the second determining module 1103 determines at least one target interval from the horizontal axis of the first curve graph based on the rising and falling trend of the first curve, including:

[0132] Determine the first starting point of each first curve, the first inflection point that appears from the first starting point, and the capacity corresponding to the inflection point on the first horizontal axis;

[0133] The average of the capacity is taken as the interval endpoint, and the interval from the second starting point on the horizontal axis to the interval endpoint is taken as a target interval.

[0134] The first inflection point in each first curve is updated to the first starting point, and the endpoint of the interval is updated to the second starting point.

[0135] In one possible implementation, after determining the second curve, the method further includes:

[0136] At least one soft-pack battery of the same model from the same batch is selected as a comparison battery, and the third curve of the comparison battery in the second curve is determined.

[0137] The third curve and the second curve are fitted together, and the fitted result is used as the second curve.

[0138] In one possible implementation, after the first determining module 1102 determines the first curve, the method further includes:

[0139] The first curve in the first curve graph is smoothed to remove points in the first curve whose fluctuation amplitude is greater than the second fluctuation threshold.

[0140] In one possible implementation, after determining the second curve, the method further includes:

[0141] The second curve in the second curve graph is smoothed to remove points in the second curve whose fluctuation amplitude is greater than the third fluctuation threshold.

[0142] In one possible implementation, the detection module 1101 further includes:

[0143] Select at least one pouch cell from the same batch and model of pouch cells as the second test cell;

[0144] For the first battery under test, the first battery under test is charged in the target range using the target charging rate that matches the target range, and the first charging result is recorded. For the second battery under test, the second battery under test is charged in the constant current charging mode, and the second charging result is recorded.

[0145] The first charging result and the second charging result are compared and verified.

[0146] In one possible implementation, the detection module 1101 records the first charging result, including:

[0147] A first coordinate system is established with the capacity of the first or second battery under test as the horizontal axis and the third thickness change value of the cell expansion during the charging process of the first or second battery under test as the vertical axis. A second coordinate system is established with the capacity of the first or second battery under test as the horizontal axis and the temperature change value of the first or second battery under test during the charging process as the vertical axis.

[0148] A first verification curve is determined in the first coordinate system to describe the cell expansion change of the first battery under test during charging, and a second verification curve is determined in the second coordinate system to describe the temperature change of the first battery under test during charging.

[0149] Record the results of the second charging, including:

[0150] A third verification curve is determined in the first coordinate system to describe the cell expansion change of the second battery under test during charging, and a fourth verification curve is determined in the second coordinate system to describe the temperature change of the second battery under test during charging.

[0151] The first charging result and the second charging result are compared and verified, including:

[0152] Based on the first and third verification curves in the first coordinate system, the cell expansion change of the first battery under test during charging is verified. Based on the second and fourth verification curves in the second coordinate system, the temperature change of the battery under test during charging is verified.

[0153] The aforementioned soft-pack battery stepped charging process determination device detects the thickness change caused by cell expansion during the charging process of the first battery under test at different rates, determines the first curve of the first battery under test at different rates, and determines the target interval for dividing the gradient based on the rising and falling trend of the first curve corresponding to different rates in the first curve. On this basis, the maximum capacity in the target interval is taken as the target capacity, and the thickness change and corresponding rate corresponding to the first curve at the target capacity are determined. Based on the thickness change and rate, a second curve is established. The rate corresponding to the inflection point where the slope change of the second curve is greater than the first fluctuation threshold is taken as the target charging rate of the target interval during the charging process. The target charging rate of the target interval determined in this way reflects the maximum rate that the target interval is adapted to to a certain extent. Therefore, the gradient of stepped charging and the current adapted to each gradient can be determined more efficiently.

[0154] like Figure 12 As shown, Figure 12 This is a schematic diagram of the composition structure of the electronic device 1200 provided in the embodiments of this application. The electronic device 1200 includes:

[0155] The device 1201 includes a processor 1201, a storage medium 1202, and a bus 1203. The storage medium 1202 stores machine-readable instructions executable by the processor 1201. When the electronic device 1200 is running, the processor 1201 communicates with the storage medium 1202 via the bus 1203. The processor 1201 executes the machine-readable instructions to perform the steps of the soft-pack battery stepped charging process step determination method described in the embodiments of this application.

[0156] In practical applications, the various components in the electronic device 1200 are coupled together via bus 1203. It is understood that bus 1203 is used to achieve communication between these components. In addition to a data bus, bus 1203 also includes a power bus, a control bus, and a status signal bus. However, for clarity, in... Figure 12 The general labeled all buses as Bus 1203.

[0157] The aforementioned electronic device detects the thickness change caused by cell expansion during the charging process of the first battery under test at different rates, determines the first curve of the first battery under test at different rates, and determines the target interval for dividing the gradient based on the rising and falling trends of the first curve corresponding to different rates in the first curve. On this basis, the maximum capacity in the target interval is taken as the target capacity, and the thickness change and corresponding rate corresponding to the first curve at the target capacity are determined. Based on the thickness change and rate, a second curve is established. The rate corresponding to the inflection point where the slope change of the second curve is greater than the first fluctuation threshold is taken as the target charging rate of the target interval during the charging process. The target charging rate of the target interval determined in this way reflects the maximum rate that the target interval is adapted to to a certain extent. Therefore, the gradient of stepped charging and the current adapted to each gradient can be determined more efficiently.

[0158] This application also provides a computer-readable storage medium storing executable instructions. When the executable instructions are executed by at least one processor 1201, the method for determining the stepped charging process of a pouch battery as described in this application is implemented.

[0159] In some embodiments, the storage medium may be a magnetic random access memory (FRAM), a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a flash memory, a magnetic surface memory, an optical disc, or a compact disc read-only memory (CD-ROM), etc.; or it may be a device that includes one or any combination of the above-mentioned memories.

[0160] In some embodiments, executable instructions may take the form of a program, software, software module, script, or code, written in any form of programming language (including compiled or interpreted languages, or declarative or procedural languages), and may be deployed in any form, including as a standalone program or as a module, component, subroutine, or other unit suitable for use in a computing environment.

[0161] As an example, executable instructions may, but do not necessarily, correspond to files in the file system. They may be stored as part of a file that holds other programs or data, for example, in one or more scripts in a HyperText Markup Language (HTML) document, in a single file dedicated to the program in question, or in multiple collaborating files (e.g., a file that stores one or more modules, subroutines, or code sections).

[0162] As an example, executable instructions can be deployed to execute on a single computing device, or on multiple computing devices located in one location, or on multiple computing devices distributed across multiple locations and interconnected via a communication network.

[0163] The aforementioned computer-readable storage medium detects the thickness change caused by cell expansion during the charging process of the first battery under test at different rates, determines the first curve of the first battery under test at different rates, and determines the target interval for dividing the gradient based on the rising and falling trends of the first curve corresponding to different rates in the first curve. On this basis, the maximum capacity in the target interval is taken as the target capacity, and the thickness change and corresponding rate corresponding to the first curve at the target capacity are determined. Based on the thickness change and rate, a second curve is established. The rate corresponding to the inflection point where the slope change of the second curve is greater than the first fluctuation threshold is taken as the target charging rate of the target interval during the charging process. The target charging rate of the target interval determined in this way reflects the maximum rate adapted to the target interval to a certain extent. Therefore, the gradient of stepped charging and the current adapted to each gradient can be determined more efficiently.

[0164] In the several embodiments provided in this application, it should be understood that the disclosed methods and electronic devices can be implemented in other ways. The device embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods, such as: multiple units or components may be combined, or integrated into another system, or some features may be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the various components shown or discussed may be through some interfaces, and the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0165] The modules described as separate components may or may not be physically separate. The components shown as modules may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0166] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0167] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a processor-executable, non-volatile, computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, a platform server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, ROM, RAM, magnetic disks, or optical disks.

[0168] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for determining the stepped charging steps of a soft-pack battery, characterized in that, Includes the following steps: Select any soft-pack battery from the same batch and model as the first test battery, charge the first test battery at different rates, and record the first thickness change value of the first test battery cell expansion and the capacity of the first test battery during the charging process. Based on the first thickness change value and the capacity of the first battery under test at different rates, a first curve is determined, wherein the first horizontal axis of the first curve represents the capacity, the first vertical axis of the first curve represents the first thickness change value, and the charging process of the first battery under test at each rate corresponds to a first curve in the first curve. Based on the rising and falling trend of the first curve, at least one target interval is determined from the horizontal axis of the first curve graph, and the maximum value of the capacity in the target interval is taken as the target capacity. Based on the second thickness change value corresponding to the target capacity in the first curve and the multiplier of the first curve corresponding to the target capacity, a second curve graph is determined, wherein the second horizontal axis of the second curve graph represents the multiplier, and the second vertical axis of the second curve graph represents the second thickness change value. Based on the slope of the second curve in the second curve graph, the turning point where the slope change is greater than the first fluctuation threshold is determined, and the multiplier corresponding to the turning point on the second horizontal axis is taken as the target charging multiplier of the target range during the charging process.

2. The method according to claim 1, characterized in that, The recorded first thickness change value of the first battery cell under test during charging includes: The negative terminal of the first battery under test is fixed, and the height change value of the plane where the positive terminal of the first battery under test is located during the charging process is detected by a displacement sensor, and the height change value is used as the first thickness change value.

3. The method according to claim 1, characterized in that, The step of determining at least one target interval from the horizontal axis of the first curve graph based on the rising and falling trend of the first curve includes: Determine the first starting point of each first curve, the first inflection point that appears from the first starting point, and the capacity corresponding to the inflection point on the first horizontal axis; The average of the capacity is taken as the interval endpoint, and the interval from the first starting point to the interval endpoint is taken as a target interval. Update the interval endpoints to the first starting point, determine the inflection points and the corresponding capacity on the first horizontal axis, and take the average of the capacity as the next interval endpoint.

4. The method according to claim 1, characterized in that, After determining the second curve, the method further includes: At least one soft-pack battery of the same model from the same batch is selected as a comparison battery, and the corresponding curve of the comparison battery is obtained as the third curve in accordance with the method of obtaining the second curve of the first battery under test. The third curve and the second curve are fitted together, and the fitted result is used as the second curve.

5. The method according to claim 1, characterized in that, After determining the first curve, the method further includes: The first curve in the first curve graph is smoothed to remove points in the first curve whose fluctuation amplitude is greater than the second fluctuation threshold. After determining the second curve, the method further includes: The second curve in the second curve graph is smoothed to remove points in the second curve whose fluctuation amplitude is greater than the third fluctuation threshold.

6. The method according to claim 1, characterized in that, The method further includes: Select at least one pouch cell from the same batch and model of pouch cells as the second test cell; For the first battery under test, the first battery under test is charged in the target range using the target charging rate that matches the target range, and the first charging result is recorded. For the second battery under test, the second battery under test is charged in the constant current charging mode, and the second charging result is recorded. The first charging result and the second charging result are compared and verified.

7. The method according to claim 6, characterized in that, The recording of the first charging result includes: A first coordinate system is established with the capacity of the first or second battery under test as the horizontal axis and the third thickness change value of the cell expansion during the charging process of the first or second battery under test as the vertical axis. A second coordinate system is established with the capacity of the first or second battery under test as the horizontal axis and the temperature change value of the first or second battery under test during the charging process as the vertical axis. A first verification curve is determined in the first coordinate system to describe the cell expansion change of the first battery under test during charging, and a second verification curve is determined in the second coordinate system to describe the temperature change of the first battery under test during charging. The recording of the second charging result includes: A third verification curve is determined in the first coordinate system to describe the cell expansion change of the second battery under test during charging, and a fourth verification curve is determined in the second coordinate system to describe the temperature change of the second battery under test during charging. The comparison and verification of the first charging result and the second charging result includes: Based on the first and third verification curves in the first coordinate system, the cell expansion change of the first battery under test during charging is verified. Based on the second and fourth verification curves in the second coordinate system, the temperature change of the battery under test during charging is verified.

8. A device for determining the stepped charging process of a soft-pack battery, characterized in that, The device includes: The detection module is used to select any one soft-pack battery from the same batch and model of soft-pack batteries as the first test battery, charge the first test battery at different rates, and record the first thickness change value of the cell expansion of the first test battery and the capacity of the first test battery during the charging process. The first determining module is used to determine a first curve based on the first thickness change value and the capacity of the first battery under test at different rates, wherein the first horizontal axis of the first curve represents the capacity, the first vertical axis of the first curve represents the first thickness change value, and the charging process of the first battery under test at each rate corresponds to a first curve in the first curve. The second determining module is used to determine at least one target interval from the horizontal axis of the first curve graph according to the rising and falling trend of the first curve, and take the maximum value of the capacity in the target interval as the target capacity, and determine the second curve graph according to the second thickness change value corresponding to the target capacity in the first curve and the multiplier of the first curve corresponding to the target capacity, wherein the second horizontal axis of the second curve graph represents the multiplier, and the second vertical axis of the second curve graph represents the second thickness change value; The third determining module is used to determine the turning point where the slope change is greater than the first fluctuation threshold based on the slope of the second curve in the second curve graph, and to take the multiplier corresponding to the turning point on the second horizontal axis as the target charging multiplier of the target range during the charging process.

9. An electronic device, characterized in that, include: The device includes a processor, a storage medium, and a bus, wherein the storage medium stores machine-readable instructions executable by the processor, and when the electronic device is running, the processor communicates with the storage medium via the bus, and the processor executes the machine-readable instructions to perform the method for determining the stepped charging process of a pouch battery as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, which, when executed by a processor, performs the method for determining the stepped charging process of a pouch battery as described in any one of claims 1 to 7.

Images