Battery cell charging method and device

Abstract

The invention discloses a battery cell charging method and device, and relates to the technical field of battery cell charging. The method comprises the following steps: carrying out a charge-discharge cycle test on a test cell, and collecting cycle test data in the charge-discharge cycle test process; constructing a lithium precipitation boundary curve for the test cell according to the cycle test data and a plurality of preset residual electric quantities; and determining a stepped charging curve below the lithium precipitation boundary curve based on the lithium precipitation boundary curve, and determining a charging scheme of a battery cell with the same model as the test battery cell according to the stepped charging curve, so as to charge a vehicle with the battery cell based on the charging scheme. According to the embodiment, the charging efficiency is improved while the charging capacity of the battery cell is fully utilized, the lithium precipitation phenomenon can be avoided when the charging scheme indicated by the stepped charging curve is adopted for charging, the use safety of the battery cell is improved, and the service life of the battery cell is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of battery cell charging, and in particular to a battery cell charging method and device. Background Art

[0002] Lithium-ion batteries are widely used in people's lives. At present, in order to ensure the safety of lithium-ion batteries, the constant current-constant voltage charging method is generally used to charge the battery cells. The charging time is long, resulting in low charging efficiency. When the charging current is set unreasonably, the battery cells are prone to lithium deposition, which reduces the battery life. Therefore, there is an urgent need for a battery charging solution that can both improve the charging efficiency and ensure the battery life. Summary of the invention

[0003] In view of this, an embodiment of the present invention provides a battery cell charging method and device, which can improve charging efficiency, avoid lithium plating, and increase the life of the battery cell.

[0004] To achieve the above object, according to one aspect of an embodiment of the present invention, a battery cell charging method is provided, comprising:

[0005] Perform charge and discharge cycle tests on the test cells and collect cycle test data during the charge and discharge cycle tests;

[0006] Constructing a lithium deposition boundary curve for the test cell according to the cycle test data and a plurality of preset remaining capacities;

[0007] A step charging curve located below the lithium deposition boundary curve is determined based on the lithium deposition boundary curve, and a charging scheme for a battery cell of the same model as the test battery cell is determined according to the step charging curve, so as to charge a vehicle having the battery cell based on the charging scheme.

[0008] To achieve the above object, according to another aspect of an embodiment of the present invention, a battery cell charging device is provided, comprising:

[0009] The acquisition module is used to perform a charge-discharge cycle test on the test cell and collect cycle test data during the charge-discharge cycle test;

[0010] A construction module, used to construct a lithium precipitation boundary curve for the test battery cell according to the cycle test data and a plurality of preset remaining capacities;

[0011] A determination module is used to determine a step charging curve located below the lithium deposition boundary curve based on the lithium deposition boundary curve, and determine a charging scheme for a battery cell of the same model as the test battery cell according to the step charging curve, so as to charge a vehicle having the battery cell based on the charging scheme.

[0012] To achieve the above objective, according to another aspect of an embodiment of the present invention, a battery-charging electronic device is provided.

[0013] An electronic device for charging a battery cell according to an embodiment of the present invention comprises: one or more processors; a storage device for storing one or more programs, and when the one or more programs are executed by the one or more processors, the one or more processors implement a battery cell charging method according to an embodiment of the present invention.

[0014] To achieve the above objective, according to another aspect of an embodiment of the present invention, a computer-readable storage medium is provided.

[0015] A computer-readable storage medium according to an embodiment of the present invention stores a computer program, and when the program is executed by a processor, a battery cell charging method according to an embodiment of the present invention is implemented.

[0016] One embodiment of the above invention has the following advantages or beneficial effects: by performing a charge and discharge cycle test on the test battery cell, a lithium precipitation boundary curve is constructed based on the cycle test data and a plurality of preset remaining capacities; then a step charging curve located below the lithium precipitation boundary curve is determined, and the charging scheme indicated by the step charging curve is used as the charging scheme for the battery cell of the same model as the test battery cell, so as to charge the vehicle with the battery cell according to the charging scheme. While fully utilizing the charging capacity of the battery cell, the charging efficiency is improved. In addition, since the step charging curve is located below the lithium precipitation boundary curve, it can be ensured that when charging is performed using the charging scheme indicated by the step charging curve, lithium precipitation will not occur, thereby improving the safety and life of the battery cell.

[0017] The further effects of the above-mentioned non-conventional optional manner will be described below in conjunction with the specific implementation manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to better understand the present invention and do not constitute an improper limitation of the present invention.

[0019] Figure 1 is a schematic flow chart of a battery cell charging method according to an embodiment of the present invention;

[0020] Figure 2 is a schematic diagram of a lithium deposition boundary curve according to an embodiment of the present invention;

[0021] Figure 3 is a schematic diagram of a process for determining a target charging rate according to an embodiment of the present invention;

[0022] Figure 4 is a schematic diagram of a curve of positive and negative electrode potential-remaining power when the preset charging rate is 0.7C according to an embodiment of the present invention;

[0023] Figure 5 is a schematic diagram of a curve of positive and negative electrode potential-remaining power at a preset charging rate of 0.9C according to an embodiment of the present invention;

[0024] Figure 6 is a curve diagram of target negative electrode potential-preset charging rate under preset remaining power according to an embodiment of the present invention;

[0025] Figure 7 is a schematic flow chart of a battery cell charging method according to another embodiment of the present invention;

[0026] Figure 8 is a curve diagram of positive and negative electrode potentials versus remaining power when the preset charging rate is 1.1C according to an embodiment of the present invention;

[0027] Fig. 9 is a curve diagram of positive and negative electrode potentials versus remaining power when the preset charging rate is 1.3C according to an embodiment of the present invention;

[0028] Fig.10 is a schematic diagram of a lithium deposition boundary curve and a step charging curve according to an embodiment of the present invention;

[0029] Fig.11 is a schematic diagram of main modules of a battery cell charging device according to an embodiment of the present invention;

[0030] Fig.12 is an exemplary system architecture diagram to which embodiments of the present invention may be applied;

[0031] Fig.13 A schematic diagram of the structure of a computer system of a terminal device or a server suitable for implementing an embodiment of the present invention. DETAILED DESCRIPTION

[0032] The following is a description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, including various details of the embodiments of the present invention to facilitate understanding, which should be considered as merely exemplary. Therefore, it should be recognized by those of ordinary skill in the art that various changes and modifications may be made to the embodiments described herein without departing from the scope and spirit of the present invention. Similarly, for clarity and conciseness, the description of well-known functions and structures is omitted in the following description.

[0033] It should be pointed out that the embodiments of the present invention and the technical features therein may be combined with each other without conflict.

[0034] Figure 1 Schematic diagram of the main steps of the battery cell charging method according to an embodiment of the present invention. Figure 1 As shown, the battery cell charging method of the embodiment of the present invention mainly includes the following steps S101 to S103:

[0035] Step S101, performing a charge-discharge cycle test on a test cell, and collecting cycle test data during the charge-discharge cycle test.

[0036] Specifically, a plurality of preset charging rates are pre-set; a charge-discharge cycle test is performed on the plurality of test cells at the preset charging rates; and during the charge-discharge cycle test, cycle test data is collected.

[0037] The test cell is a cell with a three-electrode system formed by a positive electrode, a negative electrode and a reference electrode. The reference electrode is obtained by inserting a copper strip into the cell through the cell injection hole. The positive electrode potential is determined by the potential difference between the reference electrode and the positive electrode potential, and the negative electrode potential is determined by the potential difference between the reference electrode and the negative electrode potential.

[0038] Optionally, during the charge and discharge cycle test, after each charge or discharge is completed, the test cell is left to rest for a preset time. The resting time can simulate the actual use process of the cell, reduce the internal polarization of the test cell, and prevent the negative electrode potential from quickly reaching the lithium precipitation potential. In addition, the heat accumulation inside the cell and the occurrence of side reactions can be avoided as much as possible.

[0039] In order to reduce the deviation of the cycle test data, multiple test cells can be set for each preset charging rate, and then the data of the multiple test cells at each preset charging rate are averaged to obtain the cycle test data corresponding to each preset charging rate.

[0040] The cycle test data may include the positive electrode potential, negative electrode potential and remaining power at a preset charging rate.

[0041] Step S102, constructing a lithium deposition boundary curve for the test cell according to the cycle test data and a plurality of preset remaining capacities.

[0042] A plurality of preset remaining capacities are pre-set, and the step length between adjacent preset remaining capacities may be related to the accuracy of the battery management system (BMS) and the actual application. Preferably, referring to the accuracy of the BMS, and in order to avoid power jump during battery charging, the step length between adjacent preset remaining capacities may be set to 10%. As an example, the preset remaining capacities may be 0% SOC, 10% SOC, 20% SOC, 30% SOC, 40% SOC, 50% SOC, 60% SOC, 70% SOC, 80% SOC, 90% SOC, 100% SOC.

[0043] In addition, in general, in order to avoid overcharging or over-discharging of the battery cell, the SOC safety interval of the battery cell charging solution is generally set to 20% SOC ~ 80% SOC, so as to extend the service life of the battery cell and ensure the stability of the battery cell performance. Therefore, preferably, the preset remaining power value range can be 20% SOC ~ 80% SOC. As an example, the preset remaining power can be 20% SOC, 30% SOC, 40% SOC, 50% SOC, 60% SOC, 70% SOC, 80% SOC.

[0044] Specifically, in step S102, based on the cycle test data, a plurality of target charge rates are determined for the test cell when the negative electrode potential is at a lithium deposition potential, so as to construct a lithium deposition boundary curve using the target charge rates. The lithium deposition potential is determined according to the battery system and the electrode material.

[0045] Among them, the lithium deposition potential refers to the potential at which lithium ions in the battery cell are reduced to metallic lithium at the negative electrode under specific conditions. It is understandable that the lithium deposition potential may be different for batteries of different systems and different electrode materials. For example, for a magnesium electrode, the lithium deposition potential is about -2.4V; for a graphite electrode, the lithium deposition potential is about 0V.

[0046] When the negative electrode potential is less than the lithium deposition potential, the negative electrode potential drops to Li / Li + The negative electrode is not excessive enough, so the lithium ions cannot be normally embedded in the negative electrode, and are deposited in the negative electrode in the form of metallic lithium, resulting in lithium deposition. Among them, the negative electrode excess means that the number of lithium ions contained in the negative electrode of the battery cell exceeds the number of lithium ions contained in the positive electrode.

[0047] The lithium deposition boundary curve is a curve that indicates whether lithium deposition occurs in the test cell. Figure 2 As shown, when the charge rate corresponding to the SOC is above the lithium deposition boundary curve, the test cell is charged, and lithium deposition may occur in the test cell; when the charge rate corresponding to the SOC is below the lithium deposition boundary curve, the test cell is charged, and lithium deposition may not occur in the test cell.

[0048] Step S103, determining a step charging curve below the lithium deposition boundary curve based on the lithium deposition boundary curve, determining a charging scheme for a battery cell of the same model as the test battery cell according to the step charging curve, so as to charge a vehicle having the battery cell based on the charging scheme.

[0049] According to the lithium deposition boundary curve, a step charging curve that meets the optimal charging condition and is located below the lithium deposition boundary curve is determined. Here, the optimal charging condition is to have the shortest charging time while ensuring the safety of the battery cell and preventing lithium deposition from occurring.

[0050] In an optional embodiment, if Figure 3 As shown, the above-mentioned method for determining a plurality of target charging rates for the test cell when the negative electrode potential is the lithium deposition potential for the preset remaining power includes the following steps S301 to S304:

[0051] Step S301, for each preset charging rate, determining a first correlation between the negative electrode potential and the remaining power in the cycle test data of the test cell;

[0052] For each of the above-mentioned preset remaining power, the following steps S302 to S304 are performed:

[0053] Step S302, determining a target negative electrode potential corresponding to each of the preset charging rates for the preset remaining power according to the first association relationship;

[0054] Step S303, using the target negative electrode potential corresponding to each of the preset charging rates under the preset remaining power, constructing a second association relationship between the target negative electrode potential and the preset charging rate for the preset remaining power;

[0055] Step S304, determining the target charging rate of the preset remaining power when the negative electrode potential is the lithium deposition potential according to the second association relationship.

[0056] For each preset charging rate, the cycle test data includes data such as the positive electrode potential, the negative electrode potential and the remaining power. The negative electrode potential and the remaining power are used to construct a curve graph of the positive and negative electrode potential-remaining power, and the first correlation between the negative electrode potential and the remaining power is determined based on the above curve graph of the positive and negative electrode potential-remaining power. Then, the first correlation between the negative electrode potential and the remaining power for all preset charging rates is obtained. Optionally, when constructing the curve graph of the positive and negative electrode potential-remaining power, the left ordinate can be used to represent the positive electrode potential, the right ordinate can be used to represent the negative electrode potential, and the horizontal axis can be used to represent the remaining power. As an example, when the preset charging rate is 0.7C, the following can be constructed based on the cycle test data of the 0.7C test cell: Figure 4 The curve diagram of positive and negative electrode potential-remaining power shown in FIG. 1 is as follows; when the preset charging rate is 0.9C, the cycle test data of the test cell at 0.9C can be constructed as follows Figure 5 The graph of positive and negative electrode potential-remaining capacity is shown.

[0057] Preferably, for each preset charging rate, a curve graph of the negative electrode potential and the remaining power is constructed using the negative electrode potential and the remaining power in the cycle test data, and a first correlation relationship between the negative electrode potential and the remaining power is determined based on the above curve graph of the negative electrode potential-remaining power.

[0058] After obtaining the first association relationship of all preset charging rates, the target negative electrode potential corresponding to the preset charging rate is determined for each preset remaining power in all the first association relationships, and then a second association relationship between the target negative electrode potential and the preset charging rate is constructed for each preset remaining power. As an example, assuming that the preset remaining power includes 30% SOC, 50% SOC and 70% SOC, and the preset charging rates include 0.3C, 0.5C, 0.9C and 1.5C, after obtaining the first association relationships corresponding to 0.3C, 0.5C, 0.9C and 1.5C, respectively, first for 30% SOC, the first target negative electrode potential corresponding to 30% SOC is determined in the first association relationship corresponding to 0.3C, the second target negative electrode potential corresponding to 30% SOC is determined in the first association relationship corresponding to 0.5C, the third target negative electrode potential corresponding to 30% SOC is determined in the first association relationship corresponding to 0.9C, and the fourth target negative electrode potential corresponding to 30% SOC is determined in the first association relationship corresponding to 1.5C, such as Figure 6 As shown, according to 0.3C and the first target negative electrode potential, 0.5C and the second target negative electrode potential, 0.9C and the third target negative electrode potential, and 1.5C and the fourth target negative electrode potential, a curve diagram of the target negative electrode potential-preset charging rate is constructed for 30% SOC, and then the second association relationship between the target negative electrode potential and the preset charging rate of 30% SOC is determined; similarly, for 50% SOC, the corresponding target negative electrode potential is determined in the first association relationships corresponding to 0.3C, 0.5C, 0.9C and 1.5C, respectively, as shown in FIG. Figure 6 As shown, a curve diagram of the target negative electrode potential-preset charging rate is constructed for 50% SOC, and then the second correlation relationship between the target negative electrode potential and the preset charging rate of 50% SOC is determined; for 70% SOC, the corresponding target negative electrode potential is determined in the first correlation relationship corresponding to 0.3C, 0.5C, 0.9C and 1.5C, respectively, as shown in FIG. Figure 6 As shown, a curve diagram of the target negative electrode potential-preset charging rate is constructed for 70% SOC, and then a second correlation relationship between the target negative electrode potential of 70% SOC and the preset charging rate is determined.

[0059] Since lithium deposition is likely to occur when the negative electrode potential is less than the lithium deposition potential, and lithium deposition is unlikely to occur when the negative electrode potential is greater than the lithium deposition potential, the target charging rate when the negative electrode potential is equal to the lithium deposition potential is determined. As an example, when the lithium deposition potential is 0V, for a preset remaining capacity of 30% SOC, according to the second association relationship, it can be determined that the target charging rate corresponding to 0V is 0.85C.

[0060] In an optional embodiment, a lithium deposition boundary curve may be constructed by utilizing a plurality of the above-mentioned preset remaining capacities and a target charging rate of each of the above-mentioned preset remaining capacities when the negative electrode potential is at a lithium deposition potential.

[0061] Specifically, based on a plurality of preset remaining capacities and corresponding target charging rates, the SOC is represented by the horizontal axis and the charging rate is represented by the vertical axis to construct a lithium deposition boundary curve. As an example, the lithium deposition boundary curve can be as follows: Figure 2 As shown, when the charging rate corresponding to the SOC is above the lithium deposition boundary curve, lithium deposition may occur, and when the charging rate corresponding to the SOC is below the lithium deposition boundary curve, lithium deposition may not occur.

[0062] In an optional embodiment, the step of determining the step charging curve below the lithium deposition boundary curve based on the lithium deposition boundary curve includes:

[0063] For each two adjacent preset remaining capacities, the target charging rate corresponding to the larger preset remaining capacities is used as the step platform value between the two adjacent preset remaining capacities in the step charging curve;

[0064] The target charging rate corresponding to each of the above-mentioned preset remaining power is used as the inflection point of the charging rate decrease in the step charging curve, and the difference between two adjacent target charging rates is used as the charging rate decrease gradient corresponding to the two adjacent preset remaining power in the step charging curve.

[0065] Since lithium deposition may not occur when the charging rate corresponding to the SOC is below the lithium deposition boundary curve, a step charging curve is determined below the lithium deposition boundary curve.

[0066] As an example, in the lithium plating boundary curve, such as in determining the step charging curve of 10% SOC to 30% SOC, the target charging rates corresponding to the preset remaining power of 10% SOC, 20% SOC and 30% SOC are respectively used as the descending inflection points, the target charging rate corresponding to 20% SOC is used as the step platform value of 10% SOC to 20% SOC, the target charging rate corresponding to 30% SOC is used as the step platform value of 20% SOC to 30% SOC, and the difference between the target charging rate corresponding to 20% SOC and the target charging rate corresponding to 30% SOC is used as the descending gradient of the descending inflection point of 20% SOC, thereby obtaining a step charging curve of 10% SOC to 30% SOC.

[0067] In an optional embodiment, the step of determining a charging scheme for a battery cell of the same model as the test battery cell according to the step charging curve includes:

[0068] Verify the reliability of the charging scheme indicated by the above-mentioned step charging curve;

[0069] In the case where the verification result of the above reliability verification is passed, the charging scheme indicated by the above step charging curve is determined as the charging scheme for the battery cell of the same model as the above test battery cell.

[0070] Specifically, a charging scheme indicated by a step charging curve is used to charge the battery cell of the same model as the test battery cell, and then discharge it for multiple cycles, and then determine whether lithium deposition occurs. If lithium deposition does not occur after multiple cycles of the battery cell of the same model as the test battery cell, the verification result of the reliability verification is passed; if lithium deposition occurs after multiple cycles of the battery cell of the same model as the test battery cell, the verification result of the reliability verification is failed.

[0071] When the verification result of the reliability verification fails, the step charging curve can be re-determined based on the lithium plating boundary curve charging. Specifically, in the process of re-determining the step charging curve, a charging rate reduction threshold is pre-set, and the difference between each target charging rate and the charging rate reduction threshold is used as the updated charging rate. For each adjacent two preset remaining capacities, the updated charging rate corresponding to the larger preset remaining capacities is used as the step platform value between the two adjacent preset remaining capacities in the step charging curve; the updated charging rate corresponding to each of the above preset remaining capacities is used as the charging rate reduction inflection point in the step charging curve, and the difference between the two adjacent updated charging rates is used as the charging rate reduction gradient corresponding to the two adjacent preset remaining capacities in the step charging curve, thereby obtaining a re-determined step charging curve.

[0072] After obtaining the re-determined step charging curve, the charging scheme indicated by it is subjected to reliability verification. If the reliability verification result passes, the charging scheme indicated by the re-determined step charging curve is determined as the charging scheme for the same type of battery cell as the above-mentioned test battery cell. If the reliability verification result fails, the step charging curve is re-iteratively determined until the reliability verification result passes.

[0073] The battery cell charging method is further described below through a specific embodiment.

[0074] like Figure 7 As shown, the battery cell charging method of the embodiment of the present invention may include the following steps S701 to S707:

[0075] Step S701, performing a charge-discharge cycle test on a test cell of a three-electrode system, and collecting cycle test data during the charge-discharge cycle test;

[0076] For example, the test cell may be placed at 25° C. and kept warm for 6 hours.

[0077] Preset multiple preset charging rates, such as 0.7C, 0.9C, 1.1C and 1.3C, configure at least one test cell at each preset charging rate, and charge the test cell at the preset charging rate. After charging to the highest upper limit voltage, let it stand for 1 hour. Then, discharge all test cells at a preset discharge rate of 1C to the lowest cut-off voltage and let it stand for 1 hour. Cycle 100 times. Thus, the cycle test data of all test cells are obtained.

[0078] Step S702, for each preset charging rate, determining a first correlation relationship between the negative electrode potential and the remaining power in the cycle test data of the test cell;

[0079] Exemplarily, for each preset charging rate, a curve diagram of the negative electrode potential-remaining power in the cycle test data of the test cell is determined, thereby determining the first correlation between the negative electrode range and the remaining power. The curve diagram of the positive and negative electrode potential-remaining power at the preset charging rate of 0.7C is as follows: Figure 4 As shown, the curve of positive and negative electrode potential-remaining power with a preset charging rate of 0.9C is as follows Figure 5 As shown, the curve of positive and negative electrode potential-remaining power with a preset charging rate of 1.1C is as follows Figure 8 As shown, the curve of positive and negative electrode potential-remaining power with a preset charging rate of 1.3C is as follows Fig. 9 shown.

[0080] Step S703: for each preset remaining power, perform the following operations:

[0081] According to the first association relationship, a target negative electrode potential corresponding to each of the preset charging rates is determined for the preset remaining power; a second association relationship between the target negative electrode potential and the preset charging rate is constructed for the preset remaining power by using the target negative electrode potential corresponding to each of the preset charging rates under the preset remaining power; and a target charging rate when the negative electrode potential of the preset remaining power is a lithium deposition potential is determined according to the second association relationship;

[0082] Exemplarily, the preset remaining power is: 0% SOC, 10% SOC, 20% SOC, 30% SOC, 40% SOC, 50% SOC, 60% SOC, 70% SOC, 80% SOC and 90% SOC. Figure 4 , Figure 5 , Figure 8 and Fig. 9In the corresponding first association relationship, the target negative electrode potential corresponding to 10% is determined, and according to the target negative electrode potential corresponding to 10% SOC, a curve diagram of the target negative electrode potential corresponding to the preset remaining power of 10% SOC-preset charging rate is constructed, and then the second association relationship corresponding to the preset remaining power of 10% SOC is determined; then the target negative electrode potential corresponding to 20% SOC is determined, and a curve diagram of the target negative electrode potential corresponding to the preset remaining power of 20% SOC-preset charging rate is constructed, and then the second association relationship corresponding to the preset remaining power of 20% SOC is determined...until the second association relationship corresponding to 90% SOC is determined. The second association relationships corresponding to all preset remaining powers are obtained.

[0083] The target charging rate of each preset remaining power when the negative electrode potential is the lithium deposition potential is determined in the second association relationship corresponding to all preset remaining powers.

[0084] Step S704: for each two adjacent preset remaining capacities, the target charging rate corresponding to the larger preset remaining capacities is used as the step platform value between the two adjacent preset remaining capacities in the step charging curve; the target charging rate corresponding to each of the preset remaining capacities is used as the charging rate decreasing inflection point in the step charging curve, and the difference between the two adjacent target charging rates is used as the charging rate decreasing gradient corresponding to the two adjacent preset remaining capacities in the step charging curve;

[0085] Exemplarily, for each adjacent two preset remaining capacities in 0% SOC, 10% SOC, 20% SOC, 30% SOC, 40% SOC, 50% SOC, 60% SOC, 70% SOC, 80% SOC and 90% SOC, such as 40% SOC to 50% SOC, the target charging rate corresponding to 50% SOC is used as the step platform value of 40% SOC to 50% SOC, the target charging rate corresponding to 40% SOC and 50% SOC is used as the charging rate drop inflection point, and the difference between the target charging rate corresponding to 40% SOC and the target charging rate corresponding to 50% is used as the charging rate drop gradient. Until all the step platform values, charging rate drop inflection points and charging rate drop gradients from 0% SOC to 90% SOC are obtained, a step charging curve located below the lithium precipitation boundary curve is constructed.

[0086] As an example, Fig.10 As shown, a step charging curve from 0% SOC to 90% SOC can be constructed below the lithium plating boundary curve.

[0087] Step S705, after obtaining the step charging curve, verify the reliability of the charging scheme indicated by the step charging curve;

[0088] Exemplarily, the test cell is charged using a charging scheme indicated by a step charging curve, charged to the highest upper voltage, left to stand for 1 hour, discharged at a discharge rate of 1C, discharged to the lowest cut-off voltage, and left to stand for 1 hour. The cycle is repeated 100 times. Then, it is determined whether lithium plating occurs in the test cell.

[0089] Step S706, when the reliability verification result is passed, determining the charging scheme indicated by the step charging curve as the charging scheme for the battery cell of the same model as the test battery cell;

[0090] When no lithium plating occurs in the test battery cells that have undergone reliability verification, the reliability verification result is passed.

[0091] Step S707: If the reliability verification result fails, a charge rate reduction threshold is pre-set, and the difference between each target charge rate and the charge rate reduction threshold is used as the updated charge rate. The step charging curve is re-determined based on the updated charge rate; return to step S705 to perform reliability verification on the re-determined step charging curve. Repeat steps S705 to S707 until the reliability verification result passes, and the re-determined charging scheme that passes the reliability verification result is determined as the charging scheme for the same model of battery cells as the test battery cells.

[0092] In the case that lithium plating occurs in the test battery cell that has undergone reliability verification, the reliability verification result is characterized as failing.

[0093] According to the battery cell charging method of the embodiment of the present invention, by performing a charge and discharge cycle test on the test battery cell, a lithium precipitation boundary curve is constructed based on the cycle test data and a plurality of preset remaining capacities; then, a step charging curve located below the lithium precipitation boundary curve is determined, and the charging scheme indicated by the step charging curve is used as the charging scheme for the battery cell of the same model as the test battery cell, so as to charge the vehicle with the battery cell according to the charging scheme. While fully utilizing the charging capacity of the battery cell, the charging efficiency is improved. In addition, since the step charging curve is located below the lithium precipitation boundary curve, it can be ensured that when charging is performed using the charging scheme indicated by the step charging curve, lithium precipitation will not occur, thereby improving the safety and life of the battery cell.

[0094] Fig.11 Schematic diagram of the main modules of the battery charging device according to an embodiment of the present invention. Fig.11As shown, the battery cell charging device 1100 of the embodiment of the present invention includes: an acquisition module 1101, used to perform a charge and discharge cycle test on a test battery cell, and collect cycle test data during the charge and discharge cycle test; a construction module 1102, used to construct a lithium deposition boundary curve for the test battery cell according to the above cycle test data and multiple preset remaining capacities; a determination module 1103, used to determine a step charging curve located below the above lithium deposition boundary curve based on the above lithium deposition boundary curve, and determine a charging scheme for a battery cell of the same model as the test battery cell according to the above step charging curve, so as to charge a vehicle having the above battery cell based on the above charging scheme.

[0095] In an optional embodiment of the present invention, the construction module 1102 is further used to: determine a plurality of target charging rates for the above-mentioned test battery cells with preset remaining power when the negative electrode potential is the lithium deposition potential based on the above-mentioned cycle test data; and construct a lithium deposition boundary curve using the above-mentioned target charging rate.

[0096] In an optional embodiment of the present invention, the construction module 1102 is further used to: for each preset charging rate, determine the first correlation relationship between the negative electrode potential and the remaining power in the above-mentioned cycle test data of the above-mentioned test cell; for each of the above-mentioned preset remaining power, perform the following operations: according to the above-mentioned first correlation relationship, determine the target negative electrode potential corresponding to each of the above-mentioned preset charging rates for the above-mentioned preset remaining power; using the target negative electrode potential corresponding to each of the above-mentioned preset charging rates under the above-mentioned preset remaining power, construct a second correlation relationship between the above-mentioned target negative electrode potential and the above-mentioned preset charging rate for the above-mentioned preset remaining power; according to the above-mentioned second correlation relationship, determine the target charging rate for the above-mentioned preset remaining power when the negative electrode potential is the lithium precipitation potential.

[0097] In an optional embodiment of the present invention, the determination module 1103 is further used to: for every two adjacent preset remaining powers, use the target charging rate corresponding to the larger preset remaining power as the step platform value between the two adjacent preset remaining powers in the step charging curve; use the target charging rate corresponding to each of the above preset remaining powers as the charging rate decrease inflection point in the step charging curve, and use the difference between the two adjacent target charging rates as the charging rate decrease gradient corresponding to the two adjacent preset remaining powers in the step charging curve.

[0098] In an optional embodiment of the present invention, the determination module 1103 is further used to: perform reliability verification on the charging scheme indicated by the above-mentioned step charging curve; if the verification result of the above-mentioned reliability verification is passed, determine the charging scheme indicated by the above-mentioned step charging curve as the charging scheme for the battery cell of the same model as the above-mentioned test battery cell.

[0099] In an optional embodiment of the present invention, the acquisition module 1101 is further used to: pre-set multiple preset charging rates; perform charge and discharge cycle tests on the multiple test cells at the above preset charging rates; wherein the test cells are cells with a three-electrode system formed by a positive electrode, a negative electrode and a reference electrode.

[0100] In an optional embodiment of the present invention, during the above-mentioned charge and discharge cycle test, after each charge or discharge is completed, the above-mentioned test battery cell is left to stand for a preset time.

[0101] According to the battery cell charging device of the embodiment of the present invention, by performing a charge and discharge cycle test on the test battery cell, a lithium precipitation boundary curve is constructed based on the cycle test data and a plurality of preset remaining capacities; then, a step charging curve located below the lithium precipitation boundary curve is determined, and the charging scheme indicated by the step charging curve is used as the charging scheme for the battery cell of the same model as the test battery cell, so as to charge the vehicle with the battery cell according to the charging scheme. While fully utilizing the charging capacity of the battery cell, the charging efficiency is improved. In addition, since the step charging curve is located below the lithium precipitation boundary curve, it can be ensured that when charging is performed using the charging scheme indicated by the step charging curve, lithium precipitation will not occur, thereby improving the safety and life of the battery cell.

[0102] Fig.12 An exemplary system architecture 1200 is shown to which a battery cell charging method or a battery cell charging device according to an embodiment of the present invention can be applied.

[0103] like Fig.12 As shown, the system architecture 1200 may include test cells 1201, 1202, 1203, a network 1204 and a server 1205. The network 1204 is used to provide a medium for a communication link between the terminal devices 1201, 1202, 1203 and the server 1205. The network 1204 may be wired.

[0104] During the charging cycle test, the test cells 1201 , 1202 , and 1203 interact with the server 1205 via the network 1204 , so that the server 1205 receives cycle test data and the like.

[0105] The server 1205 may be a server that provides various services, such as a background management server that processes the cycle test data sent by the test cells 1201, 1202, and 1203. The background management server may analyze the acquired cycle test, determine the lithium precipitation boundary curve, and then determine the step charging curve, and output the charging scheme indicated by the step charging curve as the charging scheme for the cell of the same model as the test cell, and then charge the vehicle having the cell according to the charging scheme.

[0106] It should be noted that the battery cell charging method provided in the embodiment of the present invention is generally executed by the server 1205 , and accordingly, the battery cell charging device is generally disposed in the server 1205 .

[0107] It should be understood that Fig.12 The number of test cells, networks and servers in the example is only for illustration purposes. Any number of terminal devices, networks and servers may be provided as required.

[0108] Reference below Fig.13 , which shows a schematic diagram of the structure of a computer system 1300 of a terminal device suitable for implementing an embodiment of the present invention. Fig.13 The terminal device shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present invention.

[0109] like Fig.13 As shown, the computer system 1300 includes a central processing unit (CPU) 1301, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 1302 or a program loaded from a storage part 1308 into a random access memory (RAM) 1303. In the RAM 1303, various programs and data required for the operation of the computer system 1300 are also stored. The CPU 1301, the ROM 1302, and the RAM 1303 are connected to each other via a bus 1304. An input / output (I / O) interface 1305 is also connected to the bus 1304.

[0110] The following components are connected to the I / O interface 1305: an input section 1306 including a keyboard, a mouse, etc.; an output section 1307 including a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker, etc.; a storage section 1308 including a hard disk, etc.; and a communication section 1309 including a network interface card such as a LAN card, a modem, etc. The communication section 1309 performs communication processing via a network such as the Internet. A drive 1310 is also connected to the I / O interface 1305 as needed. A removable medium 1311, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 1310 as needed, so that a computer program read therefrom is installed into the storage section 1308 as needed.

[0111] In particular, according to the embodiments disclosed in the present invention, the process described above with reference to the flowchart can be implemented as a computer software program. For example, the embodiments disclosed in the present invention include a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program includes a program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from the network through the communication part 1309, and / or installed from the removable medium 1311. When the computer program is executed by the central processing unit (CPU) 1301, the above-mentioned functions defined in the system of the present invention are executed.

[0112] It should be noted that the computer-readable medium shown in the present invention may be a computer-readable signal medium or a computer-readable storage medium or any combination of the above two. The computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present invention, a computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in combination with an instruction execution system, device or device. In the present invention, a computer-readable signal medium may include a data signal propagated in a baseband or as part of a carrier wave, which carries a computer-readable program code. This propagated data signal may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. Computer-readable signal media may also be any computer-readable medium other than computer-readable storage media, which may send, propagate or transmit a program for use by or in conjunction with an instruction execution system, apparatus or device. The program code contained on the computer-readable medium may be transmitted using any appropriate medium, including but not limited to: wireless, wire, optical cable, RF, etc., or any suitable combination of the above.

[0113] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present invention. In this regard, each box in the flow chart or block diagram can represent a module, a program segment, or a part of a code, and the above-mentioned module, program segment, or a part of a code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flow chart, and the combination of the boxes in the block diagram or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0114] The modules involved in the embodiments of the present invention may be implemented by software or hardware. The modules described may also be arranged in a processor. For example, they may be described as follows: a processor includes an acquisition module, a construction module, and a determination module. The names of these modules do not, in some cases, constitute limitations on the modules themselves. For example, the acquisition module may also be described as a "module for performing a charge-discharge cycle test on a test cell and collecting cycle test data during the charge-discharge cycle test."

[0115] As another aspect, the present invention also provides a computer-readable medium, which may be included in the device described in the above embodiment; or it may exist independently without being assembled into the device. The above computer-readable medium carries one or more programs, and when the above one or more programs are executed by a device, the device includes: performing a charge-discharge cycle test on the test cell, collecting cycle test data during the charge-discharge cycle test; constructing a lithium precipitation boundary curve for the test cell according to the cycle test data and multiple preset remaining capacities; determining a step charging curve below the lithium precipitation boundary curve based on the lithium precipitation boundary curve, and determining a charging scheme for a cell of the same model as the test cell according to the step charging curve, so as to charge a vehicle having the cell based on the charging scheme.

[0116] According to the technical solution of the embodiment of the present invention, by performing a charge and discharge cycle test on the test battery cell, a lithium precipitation boundary curve is constructed based on the cycle test data and multiple preset remaining capacities; then, a step charging curve located below the lithium precipitation boundary curve is determined, and the charging scheme indicated by the step charging curve is used as the charging scheme for the battery cell of the same model as the test battery cell, so as to charge the vehicle with the battery cell according to the charging scheme. While fully utilizing the charging capacity of the battery cell, the charging efficiency is improved. At the same time, since the step charging curve is located below the lithium precipitation boundary curve, it can be ensured that when charging is performed using the charging scheme indicated by the step charging curve, lithium precipitation will not occur, thereby improving the safety and life of the battery cell.

[0117] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions may occur depending on design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A battery cell charging method, characterized in that: include: Perform charge and discharge cycle tests on the test cells and collect cycle test data during the charge and discharge cycle tests; Constructing a lithium deposition boundary curve for the test cell according to the cycle test data and a plurality of preset remaining capacities; A step charging curve located below the lithium deposition boundary curve is determined based on the lithium deposition boundary curve, and a charging scheme for a battery cell of the same model as the test battery cell is determined according to the step charging curve, so as to charge a vehicle having the battery cell based on the charging scheme.

2. The battery cell charging method according to claim 1, characterized in that: The step of constructing a lithium precipitation boundary curve for the test cell according to the cycle test data and a plurality of preset remaining capacities includes: According to the cycle test data, determining a plurality of target charge rates for the test cell when the negative electrode potential is at a lithium deposition potential and the remaining power is preset; The target charging rate is used to construct a lithium deposition boundary curve.

3. The battery cell charging method according to claim 2, characterized in that: The step of determining a plurality of target charging rates for the test cell when the negative electrode potential is at a lithium deposition potential and the remaining power is preset includes: For each preset charging rate, determining a first correlation between the negative electrode potential and the remaining power in the cycle test data of the test cell; For each of the preset remaining power, perform the following operations: According to the first association relationship, determining a target negative electrode potential corresponding to each of the preset charging rates for the preset remaining power; Using the target negative electrode potential corresponding to each of the preset charging rates under the preset remaining power, a second association relationship between the target negative electrode potential and the preset charging rate is established for the preset remaining power; The target charging rate of the preset remaining power when the negative electrode potential is the lithium precipitation potential is determined according to the second association relationship.

4. The battery cell charging method according to claim 1, characterized in that: The step charging curve located below the lithium deposition boundary curve is determined based on the lithium deposition boundary curve, comprising: For each two adjacent preset remaining capacities, the target charging rate corresponding to the larger preset remaining capacities is used as the step platform value between the two adjacent preset remaining capacities in the step charging curve; The target charging rate corresponding to each of the preset remaining power is used as the charging rate decrease inflection point in the step charging curve, and the difference between two adjacent target charging rates is used as the charging rate decrease gradient corresponding to two adjacent preset remaining power in the step charging curve.

5. The battery cell charging method according to claim 1, characterized in that: The step of determining a charging scheme for a battery cell of the same model as the test battery cell according to the step charging curve includes: Conducting reliability verification on the charging scheme indicated by the step charging curve; In the case where the verification result of the reliability verification is passed, the charging scheme indicated by the step charging curve is determined as the charging scheme for the battery cell of the same model as the test battery cell.

6. The battery cell charging method according to claim 1, characterized in that: The charge-discharge cycle test on the test cell includes: Pre-set multiple preset charging rates; The charge-discharge cycle test is performed on the plurality of test cells at the preset charge rate; wherein the test cell is a cell having a three-electrode system formed by a positive electrode, a negative electrode and a reference electrode.

7. The battery cell charging method according to any one of claims 1 to 6, characterized in that: During the charge and discharge cycle test, after each charge or discharge is completed, the test battery cell is left to stand for a preset time.

8. A battery cell charging device, characterized in that: include: The acquisition module is used to perform a charge-discharge cycle test on the test cell and collect cycle test data during the charge-discharge cycle test; A construction module, used to construct a lithium precipitation boundary curve for the test battery cell according to the cycle test data and a plurality of preset remaining capacities; A determination module is used to determine a step charging curve located below the lithium deposition boundary curve based on the lithium deposition boundary curve, and determine a charging scheme for a battery cell of the same model as the test battery cell according to the step charging curve, so as to charge a vehicle having the battery cell based on the charging scheme.

9. An electronic device for charging a battery cell, characterized in that: include: one or more processors; a storage device for storing one or more programs, When the one or more programs are executed by the one or more processors, the one or more processors implement the method according to any one of claims 1 to 7.

10. A computer readable medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method according to any one of claims 1 to 7 is implemented.

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