A method, device and equipment for predicting the capacity of an electric core

Abstract

The present invention discloses a method, device and equipment for predicting the capacity of an electric core. The method for predicting the capacity of the electric core includes: performing formation on the electric core to obtain the open-circuit voltage of the electric core after the formation is completed; seeking the corresponding state of charge of the electric core in the SOC-OCV correspondence relationship according to the open-circuit voltage; wherein, the open-circuit voltage and the state of charge of the electric core are in one-to-one correspondence, and the SOC-OCV correspondence relationship represents the correspondence relationship between the open-circuit voltage and the state of charge of the electric core; discharging the power of the formed electric core to obtain the discharge capacity of the electric core; predicting the capacity of the electric core according to the discharge capacity of the electric core and the state of charge of the electric core. The embodiments of the present invention not only reduce the energy consumption in the process of testing the capacity of the electric core, thereby reducing the production cost of the electric core; but also reduce the time consumed in the process of testing the capacity of the electric core, and shorten the production cycle of the electric core product.

Description

Technical Field

[0001] The present invention relates to the field of new energy technologies, and in particular, to a method, device, and equipment for predicting the capacity of a battery cell. Background Art

[0002] In recent years, the new energy industry has developed rapidly. The market share of new energy vehicles powered by lithium-ion batteries has increased significantly. Currently, the global shipment of power batteries has increased from Gwh to Twh. The batteries used in new energy vehicles are assembled by connecting multiple single battery cells in series and parallel, which is simply referred to as a "battery system". The electrical performance of a single battery cell determines the electrical performance of the battery system. Therefore, it is crucial to detect the capacity of single battery cells during production.

[0003] However, traditional methods for detecting the capacity of battery cells require fully charging and then fully discharging the battery cells to obtain the capacity value of the battery cells. A large amount of electrical energy is consumed during the detection process, increasing the production cost of the battery cells; and the process of fully charging and discharging the battery cells takes a long time, extending the production cycle of the battery cell products. Summary of the Invention

[0004] The present invention provides a method, device, and equipment for predicting the capacity of a battery cell to reduce the energy consumption and high production cost of battery cell capacity detection; and to reduce the long time spent in the process of battery cell capacity detection and shorten the production cycle of battery cell products.

[0005] According to one aspect of the present invention, there is provided a method for predicting the capacity of a battery cell, including:

[0006] Performing formation on the battery cell to obtain the open-circuit voltage of the battery cell after the formation is completed;

[0007] According to the open-circuit voltage, seeking the corresponding state of charge of the battery cell in the SOC-OCV correspondence relationship; wherein, the open-circuit voltage and the state of charge of the battery cell are in one-to-one correspondence, and the SOC-OCV correspondence relationship represents the correspondence relationship between the open-circuit voltage and the state of charge of the battery cell;

[0008] Discharging the electric quantity of the battery cell after formation to obtain the discharge capacity of the battery cell;

[0009] Predicting the capacity of the battery cell according to the discharge capacity of the battery cell and the state of charge of the battery cell.

[0010] Optionally, before seeking the corresponding state of charge of the battery cell in the SOC-OCV correspondence relationship according to the open-circuit voltage, the method for predicting the capacity of the battery cell further includes: establishing the SOC-OCV correspondence relationship; the method for establishing the SOC-OCV correspondence relationship includes:

[0011] Obtain the SOC-V correspondence of the battery cell; the SOC-V correspondence characterizes the correspondence between the discharge voltage and the state of charge of the battery cell;

[0012] Derive the SOC-V correspondence according to the battery cell characteristic formula to obtain the SOC-OCV correspondence.

[0013] Optionally, the battery cell characteristic formula is: OCV = V 放 + IR 内 ; where OCV is the open-circuit voltage of the battery cell, I is the current of the battery cell, and R 内 is the internal resistance of the battery cell.

[0014] Optionally, the method for obtaining the open-circuit voltage of the battery cell includes:

[0015] During the formation of the battery cell, collect the formation current of the battery cell;

[0016] After the formation is completed, collect the charging voltage and internal resistance of the battery cell;

[0017] Calculate the open-circuit voltage of the battery cell according to the formation current, charging voltage and internal resistance of the battery cell.

[0018] Optionally, the calculation formula for the open-circuit voltage of the battery cell is: OCV = V 充 - IR 内 ; where OCV is the open-circuit voltage of the battery cell, V 充 is the charging voltage of the battery cell, and R 内 is the internal resistance of the battery cell.

[0019] Optionally, the calculation formula for predicting the capacity of the battery cell is: Q 总 = Q 放 / SOC; where OCV is the open-circuit voltage of the battery cell, Q 总 is the predicted capacity of the battery cell, and Q 放 is the discharge capacity of the battery cell.

[0020] Optionally, the implementation form of the SOC-OCV correspondence includes at least one of an SOC-OCV curve and an SOC-OCV database.

[0021] Optionally, after predicting the capacity of the battery cell, it further includes:

[0022] Judge whether the capacity of the battery cell meets the set capacity requirement; if so, determine that the battery cell is qualified and flow into the next process; otherwise, determine that the battery cell is unqualified and eliminate the battery cell.

[0023] According to another aspect of the present invention, there is provided a device for predicting the capacity of a battery cell, including:

[0024] A formation control module, configured to control the formation of the battery cell to obtain the open-circuit voltage of the battery cell after the formation is completed;

[0025] A parameter conversion module, configured to find the corresponding state of charge of the battery cell according to the open-circuit voltage in the SOC-OCV correspondence; wherein, the open-circuit voltage and the state of charge of the battery cell are in one-to-one correspondence, and the SOC-OCV correspondence represents the correspondence between the open-circuit voltage and the state of charge of the battery cell;

[0026] A discharge control module, configured to discharge the battery cell after the formation to empty the power of the battery cell and obtain the discharge capacity of the battery cell;

[0027] A capacity prediction module, configured to predict the capacity of the battery cell according to the discharge capacity of the battery cell and the state of charge of the battery cell.

[0028] According to another aspect of the present invention, there is provided a detection device for the capacity of a battery cell, and the electronic device includes:

[0029] At least one processor; and

[0030] A memory communicatively connected to the at least one processor; wherein,

[0031] The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the method for predicting the capacity of the battery cell according to any embodiment of the present invention.

[0032] According to another aspect of the present invention, there is provided a computer-readable storage medium storing computer instructions for causing a processor to implement the method for predicting the capacity of a battery cell according to any embodiment of the present invention when executed.

[0033] The technical solution of the embodiment of the present invention establishes the SOC-OCV correspondence, and predicts the capacity of the battery cell based on the technical principle that the open-circuit voltage and the state of charge of the battery cell are in one-to-one correspondence. Specifically, the open-circuit voltage of the battery cell is obtained at the end of the formation of the battery cell, and the state of charge value of the battery cell at this time is found in the SOC-OCV correspondence. Thereafter, the power of the battery cell is discharged, and the discharge capacity of the battery cell is calculated according to the discharge current and the discharge time, and the total capacity of the battery cell is predicted based on the discharge capacity of the battery cell and the state of charge value. Such a test method only needs to charge the battery cell during the formation and discharge based on the power after the formation, avoiding the process of fully charging and discharging the battery cell. Therefore, the embodiment of the present invention not only reduces the energy consumption during the battery cell capacity test, thereby reducing the production cost of the battery cell; but also reduces the time consumed during the battery cell capacity test, shortening the production cycle of the battery cell product.

[0034] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present invention, nor is it used to limit the scope of the present invention. Other features of the present invention will become readily understood through the following description. Description of the Drawings

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for use in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0036] Figure 1 is a flowchart of a method for predicting the capacity of an electric cell provided by an embodiment of the present invention;

[0037] Figure 2 is a schematic diagram of a SOC-OCV correspondence curve provided by an embodiment of the present invention;

[0038] Figure 3 is a flowchart of a method for establishing a SOC-OCV correspondence provided by an embodiment of the present invention;

[0039] Figure 4 is a schematic diagram of a SOC-V correspondence curve provided by an embodiment of the present invention;

[0040] Figure 5 is a flowchart of a method for obtaining the open-circuit voltage of an electric cell provided by an embodiment of the present invention;

[0041] Figure 6 is a flowchart of another method for predicting the capacity of an electric cell provided by an embodiment of the present invention;

[0042] Figure 7 is a flowchart of yet another method for predicting the capacity of an electric cell provided by an embodiment of the present invention;

[0043] Figure 8 is a schematic framework diagram of a device for predicting the capacity of an electric cell provided by an embodiment of the present invention. Detailed Embodiments

[0044] In order to enable those skilled in the art to better understand the solutions of the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

[0045] It should be noted that the terms "first", "second", etc. in the description, claims and above-mentioned drawings of the present invention are used to distinguish similar objects, and do not necessarily describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0046] Figure 1 is a flowchart of a method for predicting the capacity of an electric cell provided by an embodiment of the present invention. This embodiment is applicable to the situation of predicting the capacity of an electric cell. This method can be executed by a prediction device for the capacity of an electric cell, and the prediction device for the capacity of an electric cell can be configured in a detection device for the capacity of an electric cell. Refer to Figure 1 and the method includes:

[0047] S110. Perform formation on the electric cell to obtain the open-circuit voltage of the electric cell at the end of formation.

[0048] Among them, formation refers to the process of chemical and electrochemical reactions in which a green plate is converted into a charged state in an electrolyte, impurities are removed, and the electrochemical activity of its active material is improved; among them, a green plate refers to the plate before the formation of the electric cell. Specifically, during formation, the voltage of the electric cell can be continuously monitored, and the open-circuit voltage of the electric cell can be obtained at the end of formation.

[0049] S120. According to the open-circuit voltage, find the corresponding state of charge of the electric cell in the SOC-OCV correspondence relationship; among them, the open-circuit voltage corresponds one-to-one with the state of charge of the electric cell, and the SOC-OCV correspondence relationship represents the correspondence relationship between the open-circuit voltage and the state of charge of the electric cell.

[0050] Specifically, SOC is the abbreviation of State of Charge, which refers to the ratio of the remaining capacity of the electric cell to the capacity in the fully charged state. OCV is the abbreviation of Open Circuit Voltage, which refers to the terminal voltage of the electric cell in the open-circuit state. Figure 2 is a schematic diagram of a SOC-OCV correspondence relationship curve provided by an embodiment of the present invention. See Figure 2, the L1 curve is the SOC-DOD curve of the battery cell in the discharging state, and the L1 curve reflects the relationship between the open-circuit voltage and the state of charge value of the battery cell in the discharging state; the L2 curve is the SOC-OCV curve of the battery cell in the charging state, and the L2 curve reflects the relationship between the open-circuit voltage and the state of charge value of the battery cell in the charging state. It should be noted that DOD is the abbreviation of Depth of discharge, which refers to the ratio of the discharge capacity of the battery to its fully charged state capacity. The value of SOC reflects the remaining power in the battery cell, and the value of DOD reflects the discharged power of the battery cell. The sum of the value of SOC and the value of DOD represents the fully charged state of the battery cell, that is, the sum of the value of SOC and the value of DOD is 1. In actual use, the values of SOC and DOD can be converted according to the usage situation. The open-circuit voltage OCV corresponds one-to-one with the state of charge SOC of the battery cell. In this step, based on the SOC-OCV correspondence relationship, the state of charge value corresponding to the battery cell can be determined according to the open-circuit voltage value of the battery cell, so as to obtain the ratio of the remaining capacity of the current battery cell to its fully charged state capacity.

[0051] S130. Discharge the fully charged battery cell to obtain the discharge capacity of the battery cell.

[0052] Specifically, after the battery cell formation is completed, the battery cell is discharged to empty the power in the battery cell. By measuring the capacity of the battery cell during the discharging process, the remaining capacity (i.e., the discharge capacity) of the battery cell at the end of the formation can be obtained. Specifically, the method for measuring the power of the battery cell can be to record the discharge current and discharge time of the battery cell during the discharging process, and calculate the power in the battery cell according to the capacity calculation formula. It should be noted that the discharge current during the discharging process of the battery cell is set to a fixed value to simplify the calculation method.

[0053] S140. Predict the capacity of the battery cell based on the discharge capacity and the state of charge of the battery cell.

[0054] Specifically, according to the capacity calculation formula of the battery cell, the total capacity of the battery cell is predicted using the discharge capacity and the state of charge value of the battery cell. Exemplarily, the capacity calculation formula of the battery cell is Q 总 = Q 放 / SOC.

[0055] In an embodiment of the present invention, an SOC-OCV correspondence is established, and the capacity of the battery cell is predicted based on the technical principle that the open-circuit voltage and the state of charge of the battery cell have a one-to-one correspondence. Specifically, when the formation of the battery cell is completed, the open-circuit voltage of the battery cell is obtained, and the state-of-charge value of the battery cell at this time is sought in the SOC-OCV correspondence. After that, the battery cell is discharged until it is empty, the discharge capacity of the battery cell is calculated according to the discharge current and the discharge time, and the total capacity of the battery cell is predicted based on the discharge capacity of the battery cell and the state-of-charge value. Such a test method only requires the battery cell to be charged during formation and discharged based on the charge after formation, avoiding the process of fully charging and discharging the battery cell. Therefore, the embodiment of the present invention not only reduces the energy consumption during the battery cell capacity test, thereby reducing the production cost of the battery cell, but also reduces the time consumed during the battery cell capacity test, shortening the production cycle of the battery cell product.

[0056] Figure 3 is a flowchart of a method for establishing an SOC-OCV correspondence provided by an embodiment of the present invention. Optionally, referring to Figure 3 , for the method of predicting the capacity of the battery cell, before seeking the corresponding state of charge of the battery cell in the SOC-OCV correspondence according to the open-circuit voltage, it further includes: establishing an SOC-OCV correspondence.

[0057] The method for establishing an SOC-OCV correspondence includes:

[0058] S111. Obtain the SOC-V correspondence of the battery cell; the SOC-V correspondence represents the correspondence between the discharge voltage and the state of charge of the battery cell.

[0059] Among them, the SOC-V correspondence refers to the correspondence between the SOC value of the battery cell and the discharge voltage of the battery cell. Exemplarily, the SOC-V correspondence is determined by the grading capacity method. Since the SOC-V correspondence of battery cells of the same model has universality, this SOC-V correspondence can be applied to all battery cells of the same model. It should be noted that the SOC-V correspondence can be the correspondence between the discharge voltage and the state of charge of the battery cell, or the correspondence between the charge voltage and the state of charge of the battery cell, and can be set according to needs in actual applications.

[0060] S112. Derive the SOC-V correspondence according to the battery cell characteristic formula to obtain the SOC-OCV correspondence.

[0061] Among them, the battery cell characteristic formula defines the relationship formula between the open-circuit voltage of the battery cell and the charge / discharge voltage of the battery cell. Therefore, according to the battery cell characteristic formula, the value of the charging voltage or the discharge voltage V in the SOC-V correspondence is derived as the value of OCV, and the SOC-OCV correspondence is established based on the derived OCV value. Figure 4It is a schematic diagram of the SOC-V correspondence curve provided by an embodiment of the present invention. Refer to Figure 4 , the L3 curve is the SOC-V curve of the battery cell in the charging state, and the L3 curve reflects the relationship between the voltage and the state of charge of the battery cell in the charging state; the L4 curve is the DOD-V curve of the battery cell in the discharging state, and the L4 curve reflects the relationship between the voltage and the state of charge of the battery cell in the discharging state. The value of SOC reflects the remaining power in the battery cell, and the value of DOD reflects the discharged power of the battery cell. The sum of the value of SOC and the value of DOD represents the fully charged state of the battery cell, that is, the sum of the value of SOC and the value of DOD is 1. In actual use, the values of SOC and DOD can be converted according to the usage situation. It should be noted that the values of SOC and DOD reflect the change of the battery cell power, and the values of SOC and DOD can correspond to the charging / discharging voltage of the battery cell or the open-circuit voltage of the battery cell. Refer to Figure 2 and Figure 4 , after determining the correspondence between SOC and V, the value of OCV of the battery cell can be deduced through the battery cell characteristic formula. Since the charging / discharging voltage of the battery cell corresponds one-to-one with the value of SOC, the deduced value of OCV of the battery cell also corresponds one-to-one with the value of SOC, and the correspondence is consistent with the charging / discharging voltage of the battery cell.

[0062] Optionally, the battery cell characteristic formula is: OCV = V 放 +IR 内 ; where OCV is the open-circuit voltage of the battery cell, I is the current of the battery cell, and R 内 is the internal resistance of the battery cell. Since the embodiment of the present invention estimates the capacity of the battery cell during the discharging process, the battery cell characteristic formula defines the correspondence between the discharging voltage and the state of charge of the battery cell. Among them, the discharging current and the internal resistance of the battery cell are known. Substituting the discharging voltage of the battery cell into the above battery cell characteristic formula can deduce the value of V as the value of OCV, and the discharging voltage of the battery cell and the state of charge value of the battery cell correspond one-to-one. Furthermore, the SOC-OCV correspondence is established based on the deduced value of OCV.

[0063] Figure 5 It is a flowchart of the method for obtaining the open-circuit voltage of the battery cell provided by an embodiment of the present invention. Refer to Figure 5 , the method for obtaining the open-circuit voltage of the battery cell includes:

[0064] S113. During the formation of the battery cell, collect the formation current of the battery cell.

[0065] Specifically, during the formation of the battery cell, the formation current of the battery cell is detected. It should be noted that the current fluctuation during the formation of the battery cell is very small and can be ignored. Therefore, it is considered that the formation current of the battery cell is a fixed value when collecting the formation current of the battery cell.

[0066] S114. After formation is completed, collect the charging voltage and internal resistance of the battery cell.

[0067] Specifically, after the formation of the battery cell, detect the charging voltage and internal resistance of the battery cell. It should be noted that at this time, the change in the internal resistance of the battery cell is very small and can be ignored. Therefore, when collecting the internal resistance of the battery cell, it is considered that the internal resistance of the battery cell is a fixed value.

[0068] S115. Calculate the open-circuit voltage of the battery cell according to the formation current, charging voltage and internal resistance of the battery cell.

[0069] Specifically, according to the formation current, charging voltage and internal resistance of the battery cell, obtain the open-circuit voltage of the battery cell through a calculation formula. Exemplarily, the calculation formula for the open-circuit voltage of the battery cell is: OCV = V 充 -IR 内 , where OCV is the open-circuit voltage of the battery cell, V 充 is the charging voltage of the battery cell, and R 内 is the internal resistance of the battery cell.

[0070] Figure 6 is a flowchart of another method for predicting the capacity of a battery cell provided by an embodiment of the present invention. Optionally, the calculation formula for predicting the capacity of the battery cell is: Q 总 = Q 放 / SOC; where OCV is the open-circuit voltage of the battery cell, Q 总 is the predicted capacity of the battery cell, and Q 放 is the discharge capacity of the battery cell. Refer to Figure 6 , this method for predicting the capacity of the battery cell includes:

[0071] S210. Perform formation on the battery cell to obtain the open-circuit voltage of the battery cell at the end of formation.

[0072] S220. According to the open-circuit voltage, find the corresponding state of charge of the battery cell in the SOC-OCV correspondence; where the open-circuit voltage and the state of charge of the battery cell are in one-to-one correspondence, and the SOC-OCV correspondence represents the correspondence between the open-circuit voltage and the state of charge of the battery cell.

[0073] S230. Discharge the battery cell after formation to obtain the discharge capacity of the battery cell.

[0074] S240. The calculation formula for predicting the capacity of the battery cell is: Q 总 = Q 放 / SOC; where OCV is the open-circuit voltage of the battery cell, Q 总 is the predicted capacity of the battery cell, and Q 放 is the discharge capacity of the battery cell.

[0075] Specifically, through the calculation formula for the capacity of the battery cell Q总 =Q 放 / SOC, the total capacity of the battery cell is calculated by the discharge capacity of the battery cell and the state of charge value of the battery cell before discharge.

[0076] Optionally, the implementation form of the SOC-OCV correspondence relationship includes: at least one of a SOC-OCV curve and a SOC-OCV database.

[0077] Figure 7 is a flow chart of another method for predicting the capacity of a battery cell provided by an embodiment of the present invention. The method for predicting the capacity of a battery cell optimizes the above prediction method. Based on the above embodiments, optionally, referring to Figure 7 , the prediction method of the battery cell capacity is performed according to the following steps:

[0078] S310, the battery cell is formed, and the open circuit voltage of the battery cell at the end of the formation is obtained.

[0079] S320. According to the open circuit voltage, find the corresponding state of charge of the battery cell in the SOC-OCV correspondence relationship; wherein the open circuit voltage corresponds to the state of charge of the battery cell one-to-one, and the SOC-OCV correspondence relationship represents the correspondence between the open circuit voltage and the state of charge of the battery cell.

[0080] S330, discharging the formed battery cell to obtain the discharge capacity of the battery cell.

[0081] S340: predict the capacity of the battery cell according to the discharge capacity and the state of charge of the battery cell.

[0082] S350, determining whether the capacity of the battery cell meets the set capacity requirement; if so, the battery cell is determined to be qualified and flows into the next process; otherwise, the battery cell is determined to be unqualified and is discarded.

[0083] Specifically, the predicted cell capacity is compared with the standard cell capacity to determine whether the cell is qualified. For example, when the predicted cell capacity is less than the standard cell capacity, the cell is determined to be unqualified and is removed to prevent the unqualified cell from entering the next process.

[0084] The embodiment of the present invention calculates the total capacity of the battery cell by using the SOC-OCV correspondence relationship, the state of charge value of the battery cell and the discharge capacity of the battery cell, and compares the calculated total capacity of the battery cell with the standard capacity of the battery cell to determine whether the capacity of the battery cell meets the set capacity requirements, thereby avoiding unqualified batteries from flowing into the next process and reducing cost losses.

[0085] Figure 8 Schematic diagram of a battery cell capacity prediction device provided by an embodiment of the present invention. Figure 8 , the cell capacity prediction device comprises:

[0086] A formation control module 510 for controlling the formation of the battery cells to obtain the open-circuit voltage of the battery cells after the formation is completed;

[0087] A parameter conversion module 520 for seeking the corresponding state of charge of the battery cells according to the open-circuit voltage in the SOC-OCV correspondence; wherein, the open-circuit voltage and the state of charge of the battery cells are in one-to-one correspondence, and the SOC-OCV correspondence characterizes the correspondence between the open-circuit voltage and the state of charge of the battery cells;

[0088] A discharge control module 530 for discharging the battery cells after the formation to obtain the discharge capacity of the battery cells;

[0089] A capacity prediction module 540 for predicting the capacity of the battery cells according to the discharge capacity of the battery cells and the state of charge of the battery cells.

[0090] An embodiment of the present invention also provides a detection device for the capacity of a battery cell, including:

[0091] At least one processor; and a memory communicatively connected to the at least one processor; wherein,

[0092] The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the method for predicting the capacity of a battery cell provided in any of the above embodiments.

[0093] It should be noted that the processor can be various general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of the processor include but are not limited to a central processing unit (CPU), a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. The processor executes the various methods and processes described above.

[0094] It should be understood that various forms of the processes shown above can be used, reordering, adding, or deleting steps. For example, the steps described in the present invention can be executed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution of the present invention can be achieved, and no limitations are imposed herein.

[0095] The above specific embodiments do not constitute a limitation on the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for predicting the capacity of an electric cell, characterized in that, it includes: Performing formation on the electric cell to obtain the open-circuit voltage of the electric cell after the formation is completed; According to the open-circuit voltage, seeking the corresponding state of charge of the electric cell in the SOC-OCV correspondence relationship; wherein, the open-circuit voltage and the state of charge of the electric cell are in one-to-one correspondence, and the SOC-OCV correspondence relationship represents the correspondence relationship between the open-circuit voltage and the state of charge of the electric cell; Discharging the electric quantity of the formed electric cell to obtain the discharge capacity of the electric cell; wherein, the discharge capacity is the capacity shown by the electric cell during the process from the end of the formation of the electric cell to the discharge of the electric cell; Predict the capacity of the battery cell based on the discharge capacity and the state of charge of the battery cell; wherein, the calculation formula for predicting the capacity of the battery cell is: Q 总 = Q 放 / SOC; wherein, OCV is the open-circuit voltage of the battery cell, Q 总 is the predicted capacity of the battery cell, Q 放 is the discharge capacity of the battery cell; The method for obtaining the open-circuit voltage of the electric cell includes: During the formation of the electric cell, collecting the formation current of the electric cell; After the formation is completed, collecting the charging voltage and internal resistance of the electric cell; Calculating the open-circuit voltage of the electric cell according to the formation current, charging voltage and internal resistance of the electric cell.

2. The method according to claim 1, characterized in that, Before seeking the corresponding state of charge of the electric cell in the SOC-OCV correspondence relationship according to the open-circuit voltage, it further includes: establishing the SOC-OCV correspondence relationship; the method for establishing the SOC-OCV correspondence relationship includes: Obtaining the SOC-V correspondence relationship of the electric cell; the SOC-V correspondence relationship represents the correspondence relationship between the discharge voltage and the state of charge of the electric cell; Deriving the SOC-OCV correspondence relationship by deducing the SOC-V correspondence relationship according to the electric cell characteristic formula.

3. The method according to claim 2, characterized in that, The cell characteristic formula is: OCV = V 放 + IR 内 ; where OCV is the open circuit voltage of the cell, I is the current of the cell, and R 内 is the internal resistance of the cell.

4. The method according to claim 1, characterized in that, The calculation formula for the open-circuit voltage of the battery cell is: OCV = V 充 - IR 内 ; where OCV is the open-circuit voltage of the battery cell, V 充 is the charging voltage of the battery cell, and R 内 is the internal resistance of the battery cell.

5. The method according to claim 1, characterized in that, The implementation form of the SOC-OCV correspondence relationship includes at least one of an SOC-OCV curve and an SOC-OCV database.

6. The method according to claim 1, characterized in that, After predicting the capacity of the electric cell, it further includes: Judging whether the capacity of the electric cell meets the set capacity requirement; if so, determining that the electric cell is qualified and flowing into the next process; otherwise, determining that the electric cell is unqualified and rejecting the electric cell.

7. A device for predicting the capacity of an electric cell, characterized in that, it includes: A formation control module, used to control the formation of the electric cell to obtain the open-circuit voltage of the electric cell after the formation is completed; wherein, the method for obtaining the open-circuit voltage of the electric cell includes: during the formation of the electric cell, collecting the formation current of the electric cell; after the formation is completed, collecting the charging voltage and internal resistance of the electric cell; calculating the open-circuit voltage of the electric cell according to the formation current, charging voltage and internal resistance of the electric cell; A parameter conversion module, used to seek the corresponding state of charge of the electric cell in the SOC-OCV correspondence relationship according to the open-circuit voltage; wherein, the open-circuit voltage and the state of charge of the electric cell are in one-to-one correspondence, and the SOC-OCV correspondence relationship represents the correspondence relationship between the open-circuit voltage and the state of charge of the electric cell; A discharge control module, which is used to discharge the electricity of the cell after formation to obtain the discharge capacity of the cell; wherein, the discharge capacity is the capacity shown by the cell during the process from the end of the formation of the cell to the discharge of the cell. A capacity prediction module, which is used to predict the capacity of the battery cell according to the discharge capacity of the battery cell and the state of charge of the battery cell; wherein, the calculation formula for predicting the capacity of the battery cell is: Q 总 = Q 放 / SOC; wherein, OCV is the open-circuit voltage of the battery cell, Q 总 is the predicted capacity of the battery cell, and Q 放 is the discharge capacity of the battery cell.

8. A detection device for the capacity of a cell, characterized in that it includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein, the memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the method for predicting the capacity of the cell according to any one of claims 1-6.

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