Step charging optimization method, charging control device and computer storage medium

Abstract

The invention relates to a stepped charging optimization method, a charging control device and a computer storage medium. According to a preset charging comparison table, the polarization degree of the charging process is judged in combination with a charging SOC-OCV curve, necessary shelving steps are set to eliminate the polarization influence, and overvoltage cut-off in advance is avoided. Meanwhile, the shelving time and the charging current of the next stage are controlled, and the preset charging comparison table is optimized. The optimized stepped charging scheme not only can ensure the charging efficiency of the battery, but also can avoid polarization accumulation in the battery as much as possible, so that the charging and discharging cycle is smoothly carried out. Battery loss caused by charging is reduced, and battery life is prolonged.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a step charging optimization method, a charging control device and a computer storage medium. Background Art

[0002] With the popularization of new energy technologies, the demand for secondary batteries is also increasing; different charging schemes and charging control strategies will directly affect the charging time and service life of the battery.

[0003] At present, the most widely used charging technology is constant current and constant voltage charging, that is, charging the battery with a constant current to the cut-off voltage, and then charging it at a constant voltage at the cut-off voltage. However, due to the internal resistance of the battery itself, constant current and constant voltage charging will cause the battery polarization to accumulate continuously, and battery polarization will affect the charging speed of the battery. Among them, battery polarization refers to the phenomenon that when current passes through the battery, the battery deviates from the equilibrium electrode potential. Therefore, in the process of charging with a constant current, the polarization accumulation of the battery becomes more and more serious, thereby reducing the charging speed of the battery. Therefore, controlling and eliminating polarization is the key to achieving fast and efficient charging of the battery. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a step charging optimization method, a charging control device and a computer storage medium, which eliminate the polarization phenomenon by combining the control of the standstill time with the control of the charging current, thereby ensuring the charging efficiency.

[0005] In a first aspect, in order to solve the above technical problems, the present invention provides a step charging optimization method, which comprises:

[0006] Step 1, obtain the charging SOC-OCV curve of the calibration battery, and obtain the first preset charging reference table, wherein the SOC range pre-stored in the first preset charging reference table is 0-100%, and the SOC intervals are i, wherein the xth SOC interval corresponds to a maximum charging rate of I x , the corresponding charging time is t x , x≤i, i≥2, x and i are both integers;

[0007] Step 2, setting the initial charging stage x of the target battery to 1;

[0008] Step 3: According to the maximum charging rate I corresponding to the xth SOC interval stored in the first preset charging comparison table, x and charging time t x The target battery is charged. When the time taken to charge the target battery reaches t x When the xth charging stage ends, the target SOC is S xThe charging end voltage of the xth charging stage is V x ;

[0009] Step 4: Determine the target SOC as S based on the target SOC value and the charging SOC-OCV curve. x The corresponding dynamic OCV is V 标x , and V x and kV 标x For comparison, k is a constant; when V x ≤kV 标x , and x+1<i, then set the charging stage x=x+1 and return to step 3; when V x ≤kV 标x , and x+1≥i, then the maximum charging rate I corresponding to the x+1th SOC interval stored in the first preset charging comparison table is x+1 Charge the target battery and charge it to the upper limit voltage of the target battery; when V x >kV 标x When , the rest time after the end of the xth charging stage is obtained as t 搁x , and obtain the hold time t 搁x The corresponding shelving end voltage V 搁x ;

[0010] Step 5, when V 搁x ≤kV 标x , and x+1<i, then set the charging stage x=x+1 and return to step 3; when V 搁x ≤kV 标x , and x+1≥i, then the maximum charging rate I corresponding to the x+1th SOC interval stored in the first preset charging comparison table is x+1 The target battery is charged and charged to the upper limit voltage of the target battery.

[0011] In one embodiment of the present invention, it also includes:

[0012] Step 6, when V 搁x >kV 标x When the maximum charging rate R is obtained x+1 and charging time T x+1 , where R x+1 <I x+1 , T x+1 >t x+1 ;

[0013] Step 7: when x+1<i, set the charging stage x=x+1; set the maximum charging rate I corresponding to the xth SOC interval stored in the first preset charging comparison table x and charging time t x Modify to Rx and T x , obtain a modified charging reference table; according to the maximum power rate R corresponding to the xth SOC interval in the modified charging reference table x and charging time T x The target battery is charged. When the time taken to charge the target battery reaches T x When the xth charging stage ends, the target SOC is S x The charging end voltage of the xth charging stage is V x , then return to step 4; when x+1≥i, according to the maximum charging rate R obtained in step 6 x+1 The target battery is charged and charged to the upper limit voltage of the target battery.

[0014] In one embodiment of the present invention, in step 6,

[0015] T x+1 =t x+1 +Δt,Δt=[(V 搁x -V 标x ) / 0.002] / 60;

[0016] R x+1 =60(S x+1 -S x ) / T x+1 .

[0017] In one embodiment of the present invention, in step 1, the value range of i is 3-15.

[0018] In one embodiment of the present invention, in step 4, the holding time t 搁x The value range is 0 to 60s.

[0019] In one embodiment of the present invention, in step 4, k=1.02.

[0020] In one embodiment of the present invention, in step 2, the target battery is a lithium iron battery, and the upper limit voltage of the lithium iron battery is 3.65V; or, the target battery is a ternary battery, and the upper limit voltage of the ternary battery is 4.4V or 4.35V or 4.25V.

[0021] In one embodiment of the present invention, in step 1, the calibration battery is charged from 0% SOC to 100% SOC using a maximum charging rate less than or equal to 0.1C, and based on the OCV corresponding to the SOC in the range of 0 to 100%, the relationship between OCV and SOC is fitted to obtain the charging SOC-OCV curve of the calibration battery.

[0022] In a second aspect, the present invention also provides a charging control device, including a battery controller and a memory, wherein the memory stores a computer program that can be executed by the battery controller, and the battery controller can execute the computer program to implement the step charging optimization method described in any of the above embodiments.

[0023] In a third aspect, the present invention further provides a computer storage medium storing a computer program, wherein the computer program can be executed to implement the step charging optimization method described in any of the above embodiments.

[0024] The above technical solution of the present invention has the following beneficial effects compared with the prior art:

[0025] The step charging optimization method, charging control device and computer storage medium of the present invention; in the step charging method, the polarization degree of the charging process is judged in combination with the depolarization curve, and necessary shelving steps are set to eliminate the polarization influence and avoid premature overvoltage cutoff.

[0026] The step charging optimization method, charging control device and computer storage medium of the present invention can control the shelf time and the charging current of the next stage, which can not only ensure the charging efficiency of the battery, but also avoid the polarization accumulation inside the battery as much as possible, so that the charging and discharging cycle can proceed smoothly, reduce the loss of charging to the battery, and extend the life. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein:

[0028] Figure 1 This is a flow chart of a step charging optimization method according to an embodiment of the present invention;

[0029] Figure 2 The SOC-OCV curve and kV in step 1 of a step charging optimization method in an embodiment of the present invention 标x Curve relationship diagram with SOC;

[0030] Figure 3 The graph is a graph showing the capacity retention rate versus cycle number in the embodiments of the present invention and the comparative examples. DETAILED DESCRIPTION

[0031] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0032] In the following description, the step charging optimization method, charging control device and computer storage medium in the present invention are first specifically described, and then some embodiments and comparative examples of the step charging optimization method disclosed in the present invention are given to illustrate the significant advantages of the step charging optimization method provided by the present invention over the prior art.

[0033] According to one aspect of the embodiments of the present invention, the present invention provides a step charging optimization method, referring to Figure 1 As shown, the step charging optimization method includes the following steps:

[0034] Step 1, obtaining a charging SOC-OCV curve of a calibration battery;

[0035] It should be noted that the SOC (State of Charge) value is the ratio of the remaining capacity of the battery to the nominal capacity of the battery, and is used to reflect the remaining capacity of the battery.

[0036] The OCV (Open Circuit Voltage) value is the open circuit voltage value, which is the potential difference between the two electrodes when the battery is open and not discharged.

[0037] Specifically, the calibration battery is a battery of the same type as the target battery.

[0038] The calibration battery is charged from 0% SOC to 100% SOC using a small current less than or equal to 0.1C to obtain a charging SOC-OCV curve. Figure 2 The data is marked as a fitting curve with triangles. Each point on the curve represents the dynamic OCV corresponding to a certain SOC of this model of battery under a very small polarization state. Compared with high current charging, low current charging can more fully transfer charge to the battery and reduce the electrode polarization inside the battery. Specifically, the calibration battery is charged from 0% SOC to 100% SOC at a low current of 0.1C at 25°C to obtain the charging SOC-OCV curve.

[0039] Step 1 also includes obtaining a first preset charging reference table, wherein the range of SOC pre-stored in the first preset charging reference table is 0-100%, and the number of SOC intervals is i.

[0040] Among them, the xth SOC interval corresponds to the maximum charging rate of I x , the corresponding charging time is t x , x≤i, i≥2, x and i are both integers.

[0041] Specifically, in order to take into account that the more SOC intervals are divided, the more frequent the charging switching is, the more complicated the charging process will be, and to take into account the cut-off method when charging to the corresponding SOC value, the first preset charging reference table mentioned in this embodiment records the SOC interval, and then each SOC interval corresponds to a maximum charging rate and a charging time, wherein the charging temperature when obtaining the charging SOC-OCV curve is consistent with the charging temperature pre-stored in the first preset charging reference table, and the charging temperature can be set to 25°C but is not limited to this.

[0042] In actual use, the main concern is the charging time at 0%-90% SOC value. A more reasonable interval division of 0%-90% SOC value is 3-15 SOC intervals for stage charging. This can shorten the charging time and avoid making the charging process too complicated due to too many set charging rates.

[0043] Exemplarily, the first preset charging comparison table of the disclosed embodiment of the present invention is divided into 7 SOC intervals, i=7. Of course, in some other embodiments, the SOC interval 0-70% can be further divided, for example, it can be divided into: 0-5%, 5%-10%, 10%-20%, 20%-30%, 30%-40%, 40%-50%, 50%-60% and 60%-70%, and the corresponding maximum charging rate and charging time are: 1.45C / 2.07min for the first two stages and 1.45C / 4.14min for the last six stages. Refer to Table 1 for the charging data pre-stored in the first preset charging comparison table:

[0044] Table 1

[0045]

[0046] When x=1, the SOC range of the first SOC interval is 0-70%, the corresponding maximum charging rate I1 is 1.45C, and the charging time t1 is 4.14min;

[0047] When x=2, the SOC range of the second SOC interval is 70% to 80%, the corresponding maximum charging rate I2 is 1.2C, and the charging time t2 is 5.00min;

[0048] When x=3, the SOC range of the third SOC interval is 80% to 85%, the corresponding maximum charging rate I3 is 1.0C, and the charging time t3 is 3.00min;

[0049] When x=4, the SOC range of the fourth SOC interval is 85% to 90%, the corresponding maximum charging rate I4 is 0.8C, and the charging time t4 is 3.75min;

[0050] When x=5, the SOC range of the fifth SOC interval is 90% to 95%, the corresponding maximum charging rate I5 is 0.6C, and the charging time t5 is 5.00min;

[0051] When x=6, the SOC range of the sixth SOC interval is 95% to 98%, the corresponding maximum charging rate I6 is 0.33C, and the charging time t6 is 5.45min;

[0052] When x=7, the SOC range of the seventh SOC interval is 98% to 100%, the corresponding maximum charging rate I7 ​​is 0.15C, and the charging time t7 is set to 8min; however, in the final stage of charging, it is charged at the maximum charging rate I7 ​​until the target battery reaches the upper limit voltage.

[0053] Step 2: Set the initial charging stage x of the target battery to 1.

[0054] Step 3: According to the maximum charging rate I corresponding to the xth SOC interval stored in the first preset charging comparison table, x and charging time t x The target battery is charged. When the time taken to charge the target battery reaches t x When the xth charging stage ends, the target SOC is S x The charging end voltage of the xth charging stage is V x .

[0055] Step 4: According to the target SOC value S x The target SOC is determined by the charging SOC-OCV curve. x The corresponding dynamic OCV is V 标x , and V x and kV 标x For comparison, k is a constant;

[0056] As explained in step 3, the target SOC value S x Associating the SOC intervals divided by the first preset charging comparison table and the SOC range within each interval;

[0057] Target SOC value S1 = 70%;

[0058] Target SOC value S2 = 80%;

[0059] Target SOC value S3 = 85%;

[0060] Target SOC value S4 = 90%;

[0061] Target SOC value S5 = 95%;

[0062] Target SOC value S6 = 98%;

[0063] The target SOC value S7=100%.

[0064] According to this, on the SOC-OCV curve, according to the target SOC value S x Get the corresponding V 标x .

[0065] Furthermore, since the charging current of the calibration battery is relatively small when obtaining the charging SOC-OCV curve, in the disclosed embodiment of the present invention, the dynamic OCV is set with a coefficient k, and a tolerance is formed compared to the calibration data. The dynamic OCV within the tolerance range is considered to be an acceptable polarization degree when the battery is charged. In the embodiment of the present invention, k is exemplarily 1.02.

[0066] Based on the SOC-OCV curve, combined with kV 标x Get attached Figure 2 The curves marked with asterisks in the data are shown in the attached Figure 2 If the data is within the range below the curve marked with a mitre, the charging current is considered appropriate and polarization does not affect the normal charging and battery performance of the battery cell.

[0067] Based on the SOC-OCV curve, combined with the target SOC value S x 、V 标x and kV 标x , we get Table 2:

[0068] Table 2

[0069]

[0070] Step 4 also includes,

[0071] In some charging processes, when V x ≤kV 标x , and when x+1<i, the charging stage x=x+1 is set, and the process returns to step 3.

[0072] Where V x ≤kV 标x It means that the charging current is appropriate and polarization has no effect on the battery or the effect can be ignored.

[0073] x+1<i means that the charging interval has not yet ended, and the target SOC value S of the next SOC interval x+1 Still not 100%.

[0074] At this time, the incremental step length is set to 1, x is assigned a value, and charging continues according to the data of the next SOC interval in the first preset charging reference table, which also means that the charging stage before the assignment is charged according to the pre-stored data in the first preset charging reference table without optimization.

[0075] In some charging processes, when V x ≤kV 标x , and x+1≥i, then the maximum charging rate I corresponding to the x+1th SOC interval stored in the first preset charging comparison table is x+1 The target battery is charged and charged to the upper limit voltage of the target battery.

[0076] Where V x ≤kV 标x It indicates that the charging current is appropriate, polarization has no effect on the battery or the effect is negligible, and the charging of the pre-stored data in the first preset charging comparison table does not need to be optimized.

[0077] x+1≥i indicates that the charging interval is about to end, and the target SOC value S of the next SOC interval is x+1 When i=7, the next SOC interval is charged to the upper limit voltage.

[0078] It should be noted that the target battery is a lithium iron battery or a ternary battery.

[0079] When the charging temperature is 25°C, the lower limit voltage corresponding to the 0% SOC state of the iron-lithium battery is 2.0V or 2.5V; the upper limit voltage corresponding to the 100% SOC state of the iron-lithium battery is 3.65V.

[0080] When the charging temperature is 25°C, the lower limit voltage corresponding to the ternary battery 0% SOC state is 2.8V or 2.5V; the upper limit voltage corresponding to the ternary battery 100% SOC state is 4.4V or 4.35V or 4.25V.

[0081] In other charging processes, when V x >kV 标x When , the rest time after the end of the xth charging stage is obtained as t 搁x , and obtain the hold time t 搁x The corresponding shelving end voltage V 搁x .

[0082] Where V x >kV 标xIt indicates that the polarization phenomenon has affected the charging process. Therefore, a certain standby time t is set after the end of the xth charging stage. 搁x In order to allow the electrochemical reaction inside the battery to proceed fully and eliminate the polarization voltage. In the embodiment of the present invention, the standby time t 搁x The value range is 0 to 60s.

[0083] It should be noted that a lithium battery charging method for eliminating battery polarization by standing still has been disclosed in the prior art, but too long a standing time will directly affect the charging efficiency. Accordingly, the step charging optimization method provided by the present invention not only optimizes the first preset charging reference table and adds a standing time according to actual needs, but also controls the standing time and optimizes the subsequent charging plan according to the degree of polarization elimination after standing still, so that the charging cycle can proceed normally under the premise of ensuring charging efficiency.

[0084] Step 5,

[0085] Shelf time t 搁x In some embodiments, when V 搁x ≤kV 标x , and x+1<i, then set the charging stage x=x+1 and return to step 3;

[0086] Where V 搁x ≤kV 标x This indicates that polarization is effectively eliminated during the shelf time.

[0087] x+1<i means that the charging interval has not yet ended, and the target SOC value S of the next SOC interval x+1 Still not 100%.

[0088] At this time, the incremental step length is set to 1, x is assigned a value, and charging continues according to the data of the next SOC interval in the first preset charging reference table. In this charging stage before the assignment, after charging according to the pre-stored data in the first preset charging reference table, the rest time needs to be increased to obtain a revised charging reference table.

[0089] Shelf time t 搁x In some other embodiments, when V 搁x ≤kV 标x , and x+1≥i, then the maximum charging rate I corresponding to the x+1th SOC interval stored in the first preset charging comparison table is x+1 The target battery is charged and charged to the upper limit voltage of the target battery.

[0090] Where V 搁x ≤kV 标x It means that polarization is effectively eliminated during the shelf time.

[0091] x+1≥i indicates that the charging interval is about to end, and the target SOC value S of the next SOC interval is x+1 That is, when i=7, the battery is charged to the upper limit voltage at the maximum charging rate I7 ​​corresponding to the next SOC interval. The upper limit voltage of the target battery is described in step 4, which will not be repeated here.

[0092] Step 6, when V 搁x >kV 标x When the maximum charging rate R is obtained x+1 and charging time T x+1 , where R x+1 <I x+1 , T x+1 >t x+1 ;

[0093] Where V 搁x >kV 标x This indicates that the polarization of the target battery is not completely eliminated after the shelf time.

[0094] The next charging stage is the x+1 stage, and the maximum charging rate of the next charging stage is R x+1 Less than the maximum charging rate I of the x+1 stage in the first preset charging comparison table x+1 , indicating that the first preset charging comparison table is corrected in the next charging stage, the charging current is reduced, and the charging time is extended as compensation for the polarization elimination in the xth charging stage. That is to say, through the control of the shelf time combined with the control of the charging battery and the charging time, the polarization can be eliminated well and the charging efficiency can be guaranteed.

[0095] Extending the charging time is broken down into:

[0096] T x+1 =t x+1 +Δt,Δt=[(V 搁x -V 标x ) / 0.002] / 60;

[0097] Among them, t x+1 is the charging time of the x+1th interval in the first preset charging comparison table, T x+1 is the charging time of the x+1th charging stage in the revised charging comparison table; the difference Δt between the two is calculated by the shelf end voltage V after the shelf time ends. 搁x and dynamic OCV-V 标x Calculated, here T x+1 ,t x+1 The units of Δt are both minutes.

[0098] Reducing the charging current is specifically broken down into:

[0099] Rx+1 =60(S x+1 -S x ) / T x+1 .

[0100] Where S x+1 represents the target SOC of the x+1th charging stage, S x represents the target SOC of the xth charging stage; R x+1 Indicates the maximum charging rate in the x+1th charging stage. Since the rated capacity of the target battery is fixed, the smaller the charging rate, the smaller the corresponding charging current.

[0101] Step 7: When x+1<i, set the incremental step length to 1, assign x to set the charging stage x=x+1. Set the maximum charging rate I corresponding to the xth SOC interval stored in the first preset charging comparison table x and charging time t x Modify to R x and T x , and obtain the modified charging comparison table, where x is the result after assignment, that is, the next charging stage after shelving.

[0102] According to the maximum charging rate R corresponding to the xth SOC interval in the correction charging comparison table x and charging time T x The target battery is charged. When the time taken to charge the target battery reaches T x When the xth charging stage ends, the target SOC is S x The charging end voltage of the xth charging stage is V x .

[0103] Then return to step 4 and charge the V x Repeat step 4 to determine the degree of polarization, and then choose whether to add a rest time, and whether to correct the charging time and maximum charging rate of the next stage after the rest time, until x+1≥i.

[0104] When x+1≥i, the maximum charging rate R obtained in step 6 is x+1 Charge the target battery. It should be noted here that when x+1≥i, the next charging stage is the last charging stage. If the maximum charging rate R is required x+1 To modify the first charging preset comparison table, you need to first x+1 Calculate T x+1 , and then calculate the maximum charging rate R x+1 However, the actual charging time is not based on T x+1 As the cut-off condition, the maximum charge rate R x+1The target battery is charged to the upper voltage limit. The upper voltage limit of the target battery is described in step 4 and will not be described again here.

[0105] After completing the above steps 1 to 7, an optimized charging scheme is obtained, and the optimized charging scheme data is sorted to obtain a revised charging reference table, completing one optimization. It should be noted that the revised charging reference table can also be used as a new first charging preset reference table to re-participate in steps 1 to 7 for another optimization, and the optimization process is repeated multiple times to obtain a step charging scheme that is more suitable for the target battery.

[0106] According to another aspect of the embodiment of the present invention, the present invention also provides a charging control device, including a battery controller and a memory, the memory storing a computer program that can be executed by the battery controller, and the battery controller can execute the computer program to implement a step charging optimization method.

[0107] According to another aspect of the embodiments of the present invention, the present invention further provides a computer storage medium, wherein the computer storage medium stores a computer program, and the computer program can be executed to implement the step charging optimization method.

[0108] The following provides some embodiments and comparative examples to specifically illustrate the step charging optimization method involved in the present invention. Through the following embodiments and comparative examples, it is possible to more clearly demonstrate the significant progress and advantages of the step charging optimization method involved in the present invention compared with the existing step charging scheme. It should be understood that the following embodiments and comparative examples are not limitations of the present invention.

[0109] Comparative Example

[0110] The rated capacity of the battery involved in charging in this comparative example is 105Ah, the operating voltage range is 2.5V to 3.65V, and the charging temperature is 25°C.

[0111] This comparative example adopts the first preset charging comparison table to perform step charging on the above battery. The charging data corresponding to the specific charging method is shown in Table 1; the step result of the 60th cycle obtained by charging is shown in Table 3 below:

[0112] Table 3

[0113]

[0114] From the data in process step numbers 4 to 8 in Table 3, it can be seen that any end voltage of the comparative battery in the entire constant current charging process is higher than the kV of the first 6 stages in Table 2. 标x(k=1.02); This is because the charging rate in the first preset charging comparison table is higher than the charging rate of 0.1C when the calibrated battery is charged with the SOC-OCV curve, and the charging current in the comparison example is also higher than the charging current when the calibrated charging SOC-OCV curve is charged, resulting in a larger polarization voltage.

[0115] As polarization gradually accumulates, the end voltage at step 9 exceeds the upper limit of the working voltage of the comparative battery (3.65V), which also makes step 10 unable to proceed normally and ends prematurely after only 15ms.

[0116] Each stage of the step charging scheme uses voltage, charging time or battery capacity as the cut-off condition. For lithium-ion batteries that use ternary materials as positive electrode materials, the charging voltage platform area is shorter, so the step charging can be carried out normally by setting the charging cut-off voltage. However, for lithium-ion batteries that use lithium iron phosphate as positive electrode materials, the charging voltage platform area is longer, and the voltage changes little over a long period of time during charging, so it is usually not cut off by voltage, but by time or capacity.

[0117] This comparative example illustrates that, due to the polarization phenomenon, the existing step charging method will cause the upper limit voltage to be reached prematurely before charging to 100% SOC, resulting in premature overvoltage cutoff.

[0118] Example

[0119] The model and status of the batteries involved in charging in this embodiment are consistent with those in the comparative example.

[0120] The difference between this embodiment and the aforementioned comparative example is that the charging method is different. This embodiment modifies the first preset charging comparison table through the step charging optimization method involved in the present invention to form a modified charging comparison table.

[0121] The process results obtained by charging in this embodiment are shown in Table 4 below:

[0122] Table 4

[0123]

[0124] Referring to steps 1 to 4 in Table 4, the target battery is charged from 0% SOC to 70% SOC, and the first charging stage is performed corresponding to the first SOC interval in the first preset charging reference table, x=1, the target SOC is S1=70%, and the charging end voltage V1=3.5033V of the first charging stage.

[0125] At this time, the comparison object is 1.02V corresponding to when the SOC reaches 70% in Table 2. 标1 .

[0126] Since V1=3.5033V>3.436V=1.02V 标1 , according to step 4, it is necessary to add the hold time.

[0127] Refer to step 5 in Table 4, taking the shelf time of 10s as an example, obtain the shelf end voltage V corresponding to the shelf time 搁1 =3.4677V.

[0128] At this time, the comparison object is still the 1.02V corresponding to when the SOC reaches 70% in Table 2. 标1 .

[0129] Since V 搁1 =3.4677V>3.436V=1.02V 标1 , the polarization is not completely eliminated after being put aside, x+1=1+1=2<7, according to step 6, the maximum charging rate R2 and charging time T2 are obtained:

[0130] Δt=[(V 搁1 -V 标1 ) / 0.002] / 60≈[(3.467-3.369) / 0.002] / 60≈0.81min;

[0131] T2=t2+Δt=5+0.81=5.81min;

[0132] R2=60(S2-S1) / T2=60*(80%-70%) / 5.81≈1.03C.

[0133] Referring to step 6 in Table 4, according to step 7, the maximum charging rate I2 and charging time t2 corresponding to the second SOC interval pre-stored in the first preset charging reference table are modified to R2 and T2 respectively, and a corrected charging reference table is obtained. The target battery is charged from 70% SOC to 80% SOC, and the second charging stage ends. The charging end voltage of the second charging stage is V2 = 3.4875V.

[0134] At this time, the comparison object is 1.02V corresponding to when the SOC reaches 80% in Table 2 标2 .

[0135] Since V2=3.4875V>3.439V=1.02V 标2 , according to step 4, it is necessary to add the hold time.

[0136] Refer to step 7 in Table 4, taking the shelf time of 10s as an example, obtain the shelf end voltage V corresponding to the shelf time 搁2 =3.4563V.

[0137] At this time, the comparison object is still the 1.02V corresponding to when the SOC reaches 80% in Table 2.标2 .

[0138] Since V 搁2 =3.4563V>3.439V=1.02V 标2 , the polarization is not completely eliminated after being put aside, x+1=2+1=3<7, according to step 6, the maximum charging rate R3 and charging time T3 are obtained:

[0139] Δt=[(V 搁2 -V 标2 ) / 0.002] / 60=[(3.4563-3.372) / 0.002] / 60≈0.70min;

[0140] T3=t3+Δt=3+0.70=3.70min;

[0141] R3=60(S3-S2) / T3=60*(85%-80%) / 3.70≈0.81C.

[0142] Referring to step 8 in Table 4, according to step 7, the maximum charging rate I3 and charging time t3 corresponding to the third SOC interval pre-stored in the first preset charging reference table are modified to R3 and T3 respectively, and a corrected charging reference table is obtained. The target battery is charged from 80% SOC to 85% SOC, and the third charging stage ends. The charging end voltage of the third charging stage is V3 = 3.4804V.

[0143] At this time, the comparison object is 1.02V corresponding to when the SOC reaches 85% in Table 2 标3 .

[0144] Since V3=3.4804V>3.443V=1.02V 标3 , according to step 4, it is necessary to add the hold time.

[0145] Referring to step 9 in Table 4, taking the shelf time of 10s as an example, obtain the shelf end voltage V corresponding to the shelf time 搁3 =3.4501V.

[0146] At this time, the comparison object is still the 1.02V corresponding to when the SOC reaches 85% in Table 2. 标3 .

[0147] Since V 搁3 =3.4501V>3.443V=1.02V 标3 , the polarization is not completely eliminated after being put aside, x+1=3+1=4<7, according to step 6, the maximum charging rate R4 and charging time T4 are obtained:

[0148] Δt=[(V 搁3 -V 标3) / 0.002] / 60=[(3.4501-3.375) / 0.002] / 60≈0.6min;

[0149] T4=t4+Δt=3.75+0.6=4.35min;

[0150] R4=60(S4-S3) / T4=60*(90%-85%) / 4.35≈0.69C.

[0151] Referring to step 10 in Table 4, according to step 7, the maximum charging rate I4 and charging time t4 corresponding to the 4th SOC interval pre-stored in the first preset charging reference table are modified to R4 and T4 respectively, and a corrected charging reference table is obtained. The target battery is charged from 85% SOC to 90% SOC, and the fourth charging stage ends. The charging end voltage of the fourth charging stage is V4 = 3.4618V.

[0152] At this time, the comparison object is 1.02V corresponding to when the SOC reaches 90% in Table 2 标4 .

[0153] Since V4=3.4618V>3.447V=1.02V 标4 , according to step 4, it is necessary to add the hold time.

[0154] Referring to step 11 in Table 4, taking the shelf time of 10s as an example, obtain the shelf end voltage V corresponding to the shelf time 搁4 =3.4452V.

[0155] At this time, the comparison object is still the 1.02V corresponding to when the SOC reaches 90% in Table 2. 标4 .

[0156] Since V 搁4 =3.4452V<3.447V=1.02V 标4 According to step 5, x+1=4+1=5<7, then set the charging stage x=x+1=5, return to step 3, and charge the target battery according to the maximum charging rate I5 and charging time t5 corresponding to the 5th SOC interval pre-stored in the first preset charging comparison table. Referring to Table 1, it can be seen that I5=0.6C, t5=5.00min.

[0157] Referring to step 12 in Table 4, the target battery is charged from 90% SOC to 95% SOC, and the fifth charging stage ends. The charging end voltage V5 of the fifth charging stage is 3.4598V.

[0158] At this time, the comparison object is 1.02V corresponding to when the SOC reaches 95% in Table 2 标5 .

[0159] Since V5=3.4598V>3.458V=1.02V 标5 , according to step 4, it is necessary to add the hold time.

[0160] Referring to step 13 in Table 4, taking the shelf time of 10s as an example, obtain the shelf end voltage V corresponding to the shelf time 搁5 =3.4410V.

[0161] At this time, the comparison object is still the 1.02V corresponding to when the SOC reaches 95% in Table 2. 标5 .

[0162] Since V 搁5 =3.4410V<3.458V=1.02V 标5 , no need to put it aside, according to step 5, x+1=5+1=6<7, then set the charging stage x=x+1=6, return to step 3, and charge the target battery according to the maximum charging rate I6 and charging time t6 corresponding to the 6th SOC interval pre-stored in the first preset charging comparison table. Referring to Table 1, it can be seen that I6=0.33C, t6=5.45min.

[0163] Referring to step 14 in Table 4, the target battery is charged from 95% SOC to 98% SOC, and the sixth charging stage ends. The charging end voltage V6 of the sixth charging stage is 3.4432V.

[0164] At this time, the comparison object is 1.02V corresponding to when the SOC reaches 98% in Table 2 标6 .

[0165] Since V6=3.4432V<3.478V=1.02V 标6 , no need to put it aside, according to step 5, x+1=6+1=7=i, then the target battery is charged according to the maximum charging rate I7 ​​corresponding to the 7th SOC interval pre-stored in the first preset charging comparison table. Referring to Table 1, it can be seen that I7=0.15C, and the target battery is charged to the upper limit voltage of 3.65V in this embodiment.

[0166] In summary, a step charging optimization of the target battery in the embodiment of the present invention is completed. According to the charging method of the target battery in the present embodiment, a corrected charging reference table is obtained. The corrected charging reference table is obtained by optimizing the first preset charging reference table according to the step charging optimization method involved in the present invention. In the present embodiment, the corrected charging reference table is shown in Table 5 below:

[0167] Table 5

[0168]

[0169] Of course, the above-mentioned revised charging comparison table can be used as a new first charging preset comparison table, and steps 1 to 7 are repeated again, and the step charging optimization method of the present invention is revised and optimized again. Repeat the revision and optimization multiple times to obtain a step charging scheme with a good charging and discharging cycle trend.

[0170] Reference Figure 3 As shown, even if the battery in the comparative example using the first preset charging comparison table is not over-voltage cutoff in advance, the battery cycle decay rate in the comparative example is faster than that in the embodiment. The optimized step charging scheme in the embodiment can ensure the charging efficiency of the lithium-ion battery and is beneficial to the electrochemical kinetic balance inside the battery, thereby reducing battery loss and extending service life.

[0171] It should be noted that, in the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. It should be noted that the terms used here are only for describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0172] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0173] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of this application.

[0174] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and changes. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application. The above embodiments are merely examples for clear explanation and are not limitations on the implementation methods. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from this are still within the protection scope of the present invention.

Claims

1. A step charging optimization method, characterized in that: include, Step 1, obtain the charging SOC-OCV curve of the calibration battery, and obtain the first preset charging reference table, wherein the SOC range pre-stored in the first preset charging reference table is 0-100%, and the SOC intervals are i, wherein the xth SOC interval corresponds to a maximum charging rate of I x , the corresponding charging time is t x , x≤i, i≥2, x and i are both integers; Step 2, setting the initial charging stage x of the target battery to 1; Step 3: According to the maximum charging rate I corresponding to the xth SOC interval stored in the first preset charging comparison table, x and charging time t x The target battery is charged. When the time taken to charge the target battery reaches t x When the xth charging stage ends, the target SOC is S x The charging end voltage of the xth charging stage is V x ; Step 4: Determine the target SOC as S based on the target SOC value and the charging SOC-OCV curve. x The corresponding dynamic OCV is V 标x , and V x and kV 标x For comparison, k is a constant; when V x ≤kV 标x , and x+1<i, then set the charging stage x=x+1 and return to step 3; when V x ≤kV 标x , and x+1≥i, then the maximum charging rate I corresponding to the x+1th SOC interval stored in the first preset charging comparison table is x+1 Charge the target battery and charge it to the upper limit voltage of the target battery; when V x >kV 标x When , the rest time after the end of the xth charging stage is obtained as t 搁x , and obtain the hold time t 搁x The corresponding shelving end voltage V 搁x ; Step 5, when V 搁x ≤kV 标x , and x+1<i, then set the charging stage x=x+1 and return to step 3; when V 搁x ≤kV 标x , and x+1≥i, then the maximum charging rate I corresponding to the x+1th SOC interval stored in the first preset charging comparison table is x+1 The target battery is charged and charged to the upper limit voltage of the target battery.

2. The step charging optimization method according to claim 1, characterized in that: Also includes, Step 6, when V 搁x >kV 标x When the maximum charging rate R is obtained x+1 and charging time T x+1 , where R x+1 <I x+1 , T x+1 >t x+1 ; Step 7: when x+1<i, set the charging stage x=x+1; set the maximum charging rate I corresponding to the xth SOC interval stored in the first preset charging comparison table x and charging time t x Modify to R x and T x , obtain a modified charging reference table; according to the maximum power rate R corresponding to the xth SOC interval in the modified charging reference table x and charging time T x The target battery is charged. When the time taken to charge the target battery reaches T x When the xth charging stage ends, the target SOC is S x The charging end voltage of the xth charging stage is V x , then return to step 4; when x+1≥i, according to the maximum charging rate R obtained in step 6 x+1 The target battery is charged and charged to the upper limit voltage of the target battery.

3. The step charging optimization method according to claim 2, characterized in that: In step 6, T x+1 =t x+1 +Δt,Δt=[(V 搁x -V 标x ) / 0.002] / 60; R x+1 =60(S x+1 -S x ) / T x+1 。 4. The step charging optimization method according to claim 1, characterized in that: In step 1, the value range of i is 3 to 15.

5. The step charging optimization method according to claim 1, characterized in that: In step 4, the holding time t 搁x The value range is 0 to 60s.

6. The step charging optimization method according to claim 1, characterized in that: In step 4, k=1.

02.

7. The step charging optimization method according to claim 1, characterized in that: In the step 2, the target battery is a lithium iron battery, and the upper limit voltage of the lithium iron battery is 3.65V; or, the target battery is a ternary battery, and the upper limit voltage of the ternary battery is 4.4V or 4.35V or 4.25V.

8. The step charging optimization method according to claim 1, characterized in that: In the step 1, the calibration battery is charged from 0% SOC to 100% SOC using a maximum charging rate less than or equal to 0.1C, and based on the OCV corresponding to the SOC in the range of 0 to 100%, the relationship between OCV and SOC is fitted to obtain the charging SOC-OCV curve of the calibration battery.

9. A charging control device, characterized in that: It comprises a battery controller and a memory, wherein the memory stores a computer program that can be executed by the battery controller, and the battery controller can execute the computer program to implement the step charging optimization method described in any one of claims 1 to 8.

10. A computer storage medium, characterized in that: The computer storage medium stores a computer program, and the computer program can be executed to implement the step charging optimization method according to any one of claims 1 to 8.

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