Method of generating a scheme for MSCC charging and method of manufacturing a secondary battery using the scheme

Abstract

According to an exemplary embodiment, a method for generating a scheme for MSCC (Multi-Step Constant Current) charging is provided. The method includes: charging a modeled battery cell to collect charging data of the modeled battery cell; deriving a current-capacitance model based on the charging data; and generating an MSCC (Multi-Step Constant Current) charging scheme based on the current-capacitance model.

Description

Technical Field

[0001] This disclosure relates to a method for generating MSCC (Multi-Step Constant Current) charging and a method for manufacturing a secondary battery using the method.

[0002] This application claims the benefit of Korean Patent Application No. 10-2024-0139120, filed on October 14, 2024, the disclosure of which is incorporated herein by reference. Background Technology

[0003] Unlike primary batteries, secondary batteries can be charged and discharged multiple times. They are widely used as a power source for various wireless devices such as mobile phones, laptops, and cordless vacuum cleaners. In recent years, due to increased energy density and economies of scale, the manufacturing cost per unit capacity of secondary batteries has decreased significantly, and the driving range of BEVs (battery electric vehicles) has reached levels comparable to fuel-powered vehicles, shifting the primary application of secondary batteries from mobile devices to mobility services.

[0004] The manufacturing of secondary batteries includes: electrode processes, which include mixing, coating, rolling, slitting and grooving processes; assembly processes that embed electrode components into the casing; and activation processes that electro-activate and stabilize the battery cells. Summary of the Invention

[0005] Technical issues The technical problem to be solved by the present invention is to provide a method for generating MSCC (Multi-Step Constant Current) charging scheme, which can improve the throughput of secondary battery manufacturing methods.

[0006] Technical solution According to an exemplary embodiment of this disclosure, in order to solve the above-mentioned problems, a method for generating a scheme for MSCC (Multi-Step Constant Current) charging is provided. The method includes: charging a modeled battery cell to collect charging data of the modeled battery cell; deriving a current-capacitance model based on the charging data; and generating an MSCC (Multi-Step Constant Current) charging scheme based on the current-capacitance model.

[0007] The scheme includes the number of steps in MSCC charging.

[0008] The scheme includes the current magnitude for each step in the MSCC charging process.

[0009] The current-capacitance model represents the relationship between the magnitude of the current applied to the modeled cell and the capacitance of the equivalent capacitor of the modeled cell.

[0010] The scheme is also generated based on the following first formula.

[0011] [First Formula]

[0012] Here, t n I is the duration of the nth step of MSCC charging. n It is the current magnitude of the nth step of MSCC charging, V MCn The voltage, V, applied to the modeled cell at the end of the nth step of MSCC charging. Rn The voltage, V, applied to the equivalent resistor of the modeled cell during the nth step of MSCC charging. n C is the voltage C applied to the equivalent capacitor of the modeled cell at the beginning of the nth step of MSCC charging. b (I n The current magnitude in the nth step of MSCC charging is I. n The capacitance of the equivalent capacitor of the modeled cell is determined based on the current-capacitance model, and n is an integer greater than or equal to 1.

[0013] [Second Formula]

[0014] Here, R B It is the resistance value of the equivalent resistor in the modeled battery cell.

[0015] V n The following third formula is satisfied, where [Third Formula]

[0016] Here, V MCn-1 It is the voltage applied to the modeled cell at the end of the (n-1)th step of MSCC charging, and I n-1 It is the current magnitude of the (n-1)th step of MSCC charging.

[0017] The proposed scheme is determined using SLSQP (Sequential Least Squares Programming).

[0018] SLSQP includes conditions that minimize the MSCC charging time according to the scheme.

[0019] The current magnitude of each step in the MSCC charging process of the scheme is greater than the current magnitude of subsequent steps in the MSCC charging process of the scheme.

[0020] A method for manufacturing a secondary battery includes: generating a scheme for MSCC charging; and charging a plurality of battery cells based on the scheme, wherein the plurality of battery cells are connected in series.

[0021] The scheme is generated based on the current-capacitance model, and the current-capacitance model represents the correspondence between the magnitude of the current applied to the modeled cell and the capacitance of the equivalent capacitor of the modeled cell.

[0022] The modeled cells are manufactured using the same manufacturing process as the multiple battery cells.

[0023] The scheme includes the number of steps in MSCC charging.

[0024] The scheme includes the current magnitude for each step in the MSCC charging process.

[0025] Beneficial effects According to an exemplary embodiment of this disclosure, the MSCC (Multi-Step Constant Current) charging scheme provides a current magnitude for each of the steps, which can minimize the charging speed based on the number of MSCC charging steps. Therefore, by determining the number of steps in the MSCC charging scheme and the current magnitude for each step, the throughput of secondary battery manufacturing can be improved.

[0026] The effects obtainable from the exemplary embodiments of this disclosure are not limited to those described above, and other unmentioned effects can be clearly deduced and understood by those skilled in the art to which the exemplary embodiments of this disclosure pertain. In other words, those skilled in the art can also deduce unintended effects from implementing the exemplary embodiments of this disclosure. Attached Figure Description

[0027] Figure 1 This is a flowchart illustrating a method for generating MSCC (Multi-Step Constant Current) charging according to an exemplary embodiment.

[0028] Figure 2 This shows a circuit diagram for charging a modeled battery cell.

[0029] Figure 3 The changes in current and voltage during MSCC charging are shown over time.

[0030] Figure 4 This is a capacity-voltage curve of MSCC charging.

[0031] Figure 5 This is a capacitor-current curve for MSCC charging.

[0032] Figure 6 This is a graph showing the correspondence between the number of steps in an MSCC charging scheme according to an exemplary embodiment and the current magnitude of each step.

[0033] Figure 7 This is a flowchart illustrating a method for manufacturing a secondary battery according to an exemplary embodiment.

[0034] Figure 8 This is a flowchart illustrating a method for manufacturing a secondary battery according to an exemplary embodiment.

[0035] Figure 9 The simulation time parameters for generating MSCC charge based on the number of steps in MSCC charging are shown, along with the measurement time required for actual MSCC charging. Detailed Implementation

[0036] Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. It should be noted that the terms and words used in this specification and claims should not be interpreted according to their ordinary or dictionary meanings, but rather based on the principle that the inventor may have defined the terms and concepts for the purpose of best interpreting the disclosure, and should be interpreted in a meaning and concept consistent with the technical concept of the present disclosure.

[0037] Therefore, it should be understood that the embodiments described herein and the structures shown in the accompanying drawings are only the most preferred embodiments of this disclosure and do not represent all technical concepts of this disclosure. Furthermore, at the time of filing this application, there may be various equivalent solutions and modifications that can replace them.

[0038] Furthermore, in describing this disclosure, specific descriptions of the structure or features of a related disclosure are omitted where it is believed that such specific descriptions would obscure the essence of this disclosure.

[0039] Because embodiments of this disclosure are provided to illustrate the disclosure more fully to those skilled in the art, the shapes and dimensions of the components in the drawings may be exaggerated, omitted, or shown schematically for clarity. Therefore, the dimensions or proportions of the individual components do not necessarily represent their actual dimensions or proportions.

[0040] (First Implementation) Figure 1 This is a flowchart illustrating a method for generating MSCC (Multi-Step Constant Current) charging according to an exemplary embodiment.

[0041] Figure 2 This shows a circuit diagram for charging the modeled battery cell MC.

[0042] Figure 3 The changes in current and voltage during MSCC charging are shown over time.

[0043] Figure 4 This is a capacity-voltage curve of MSCC charging.

[0044] Figure 5 This is a capacitor-current curve for MSCC charging.

[0045] Figure 6 This is a graph showing the correspondence between the number of steps in an MSCC charging scheme according to an exemplary embodiment and the current magnitude of each step.

[0046] Reference Figures 1 to 3 In P110, the modeled battery cell MC can be charged to collect charging data for the modeled battery cell MC. This is similar to simultaneously charging multiple battery cells (BC1, BC2, ..., BCN). Figure 8 Unlike other methods, the modeled battery cell MC can be charged independently. That is, the modeled battery cell MC can be charged while it is mounted in a charging facility that includes a variable current source configured to supply a current IS, and charging data can be acquired during the charging of the modeled battery cell MC, including the electrical parameters of the modeled battery cell MC (e.g., voltage, current, and capacity).

[0047] A modeled battery cell (MC) may include a cell housing and electrode assemblies housed within the cell housing. The modeled battery cell (MC) may also include, but is not limited to, an electrolyte injected into the cell housing. For example, the modeled battery cell (MC) may include a solid electrolyte incorporated into the electrode assemblies.

[0048] According to an exemplary embodiment, the electrode assembly may include a laminated structure comprising a plurality of positive electrodes, a plurality of negative electrodes, and a plurality of spacers separating the plurality of positive electrodes and the plurality of negative electrodes. According to other exemplary embodiments, the electrode assembly may include a wound structure comprising positive electrodes, negative electrodes, and spacers. The cell housing may include any of a prismatic metal can, a cylindrical metal can, and a bag-shaped housing comprising a layer of laminated metal (e.g., aluminum).

[0049] Each of the plurality of positive electrodes may include a positive electrode current collector and a positive electrode active material. The thickness of the positive electrode current collector may range from about 3 μm to about 500 μm. The positive electrode current collector does not cause chemical changes in the final manufactured secondary battery and may have high conductivity. The positive electrode current collector may include, for example, any of stainless steel, nickel, titanium, calcined carbon, and aluminum. The positive electrode current collector may include stainless steel with a surface treated with carbon, nickel, titanium, silver, etc. The surface of the positive electrode current collector may include a finely non-uniform structure to increase the adhesion of the active material. The shape of the positive electrode current collector may include any of the following: film, sheet, foil, mesh, porous, foam, and non-woven fabric.

[0050] Positive electrode active materials are substances capable of inducing electrochemical reactions. Positive electrode active materials can be lithium transition metal oxides. Positive electrode active materials can include any of the following compounds: layered compounds of lithium cobalt oxide (LiCoO2) and lithium nickel oxide (LiNiO2) replaced by one or more transition metals; lithium manganese oxide replaced by one or more transition metals; and compounds of the formula LiNi 1-y M y Lithium-nickel based oxides represented by O2 (where M is any one of Co, Mn, Al, Cu, Fe, Mg, B, Cr, Zn, and Ga, and 0.01 ≤ y ≤ 0.7); Li 1+z Ni b Mn c Co 1-(b+c+d) M d O (2-e) A e (Where -0.5≤z≤0.5, 0.1≤b≤0.8, 0.1≤c≤0.8, 0≤d≤0.2, 0≤e≤0.2, b+c+d<1, M is any one of Al, Mg, Cr, Ti, Si, and Y, and A is any one of F, P, and Cl) represents a lithium nickel cobalt manganese composite oxide, such as Li 1+ z Ni 1 / 3 Co 1 / 3 Mn 1 / 3 O2, Li 1+z Ni 0.4 Mn 0.4 Co 0.2 O2; and Li 1+x M 1-y M' y PO 4-z X zAn olivine-based lithium metal phosphate represented by (where M is a transition metal, more specifically, M is any one of Fe, Mn, Co, and Ni, M' is any one of Al, Mg, and Ti, X is any one of F, S, and N, -0.5 ≤ x ≤ +0.5, 0 ≤ y ≤ 0.5, and 0 ≤ z ≤ 0.1).

[0051] Each of the plurality of negative electrodes (EN) may include a negative electrode current collector and a negative electrode active material. The thickness of the negative electrode current collector may be in the range of about 3 μm to about 500 μm. The negative electrode current collector does not cause chemical changes in the finally manufactured secondary battery and may have high conductivity. The negative electrode current collector may include any one of copper, stainless steel, aluminum, nickel, titanium, calcined carbon, and aluminum cadmium alloy. The negative electrode current collector may include stainless steel with a surface treated with carbon, nickel, titanium, silver, etc. The surface of the negative electrode current collector may include a fine uneven structure to enhance the adhesion of the active material. The shape of the negative electrode current collector may include any one of film-like, sheet-like, foil-like, net-like, porous, foam-like, and non-woven fabric-like.

[0052] The negative electrode active material may include, for example, carbon, such as carbon that is difficult to be graphitized (hard carbon) and graphite-based carbon. The negative electrode active material may include, for example, metal composite oxides, such as Li x Fe2O3 (0 ≤ x ≤ 1), Li x WO2 (0 ≤ x ≤ 1), Sn x Me 1-x Me' y O z (where Me is any one of Mn, Fe, Pb, and Ge, Me' is any one of Al, B, P, Si, Group 1 elements, Group 2 elements, Group 3 elements, and halogens; 0 < x ≤ 1, 1 ≤ y ≤ 3, and 1 ≤ z ≤ 8). The negative electrode active material may include, for example, any one of lithium metal, lithium alloy, silicon-based alloy, and tin-based alloy. The negative electrode active material may include, for example, metal oxides, such as SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4, and Bi2O5. The negative electrode active material may also include, for example: conductive polymers such as polyacetylene; lithium cobalt nickel-based materials, etc.

[0053] Electrolytes can be any of the following: non-aqueous electrolytes, aqueous electrolytes, ionic electrolytes, and gel electrolytes. Electrolytes can be solid electrolytes. Non-aqueous electrolytes can include: organic solvents, such as ethylene carbonate and dimethyl carbonate; and lithium salts dissolved in such organic solvents, such as LiPF6 and LiBF4. Non-aqueous electrolytes can include ethylene carbonate dissolved in tetraethylammonium salt. Aqueous electrolytes can include sodium chloride solutions, sulfuric acid solutions, hydrochloric acid solutions, and sodium hydroxide solutions. Ionic electrolytes are ionic compounds that are liquid at room temperature, such as ethylmethylimidazolium bis(trifluoromethanesulfonyl)amide, and have high thermal stability. Gel electrolytes can be provided by using liquid electrolytes with polyacrylonitrile and PVA. Solid electrolytes can include lithium-doped polymeric materials (e.g., polyethylene oxide (PEO)) and ceramic electrolytes composed of ceramic materials such as NASICON and LLZO.

[0054] The modeled battery cell MC can be modeled as an equivalent resistor RB and an equivalent capacitor CB. The modeled battery cell MC can be charged using the MSCC charging method, but is not limited to this. Typically, the current IS in the preceding step of MSCC charging can be greater than the current IS in the following step. For example, as... Figure 3 As shown in the curve, the magnitude of the current IS in the first step can be greater than the magnitude of the current IS in the second step, the magnitude of the current IS in the second step can be greater than the magnitude of the current IS in the third step, the magnitude of the current IS in the third step can be greater than the magnitude of the current IS in the fourth step, and the magnitude of the current IS in the fourth step can be greater than the magnitude of the current IS in the fifth step.

[0055] The voltage VMC applied to the model cell MC is the sum of the voltage VRB applied to the equivalent resistor RB and the voltage VCB applied to the equivalent capacitor CB. Correspondingly, the voltage VCB applied to the equivalent capacitor CB is equal to the difference between the voltage VMC applied to the model cell MC and the voltage VRB applied to the equivalent resistor RB.

[0056] In each step of the MSCC charging process, the model cell MC is charged to the charging voltage VC, and the voltage VRB applied to the equivalent resistor RB is proportional to the current. As the magnitude of the current IS decreases from the previous step to the next, the voltage VRB applied to the equivalent resistor RB decreases, and therefore the voltage VMC applied across the model cell MC also decreases. As the equivalent capacitor CB is charged by the current IS, the voltage VMC applied to the model cell MC rises again to the charging voltage VC.

[0057] Charging the model cell MC stores the target capacity in the equivalent capacitor CB of each model cell MC. This is equivalent to charging the equivalent capacitor CB with the current IS so that the voltage VCB applied to the equivalent capacitor CB becomes the target voltage.

[0058] When each modeled cell MC is charged to the charging voltage VC with a sufficiently low current IS in the final step of MSCC, the equivalent capacitor CB of each modeled cell MC can be charged to the target capacity.

[0059] Next, refer to Figure 1 , Figure 2 , Figure 4 and Figure 5 In P120, the current-capacitance model can be derived based on charging data.

[0060] like Figure 4 As shown, in steps one through eight of MSCC charging, it is confirmed that the slope of the capacity-voltage curve remains at least partially unchanged. Since the slope of the capacity-voltage curve is the same as the capacitance of the equivalent capacitor CB of each modeled cell MC, sufficient consistency with the capacitance of the equivalent capacitor CB of the modeled cell MC is guaranteed even when the capacitance of the equivalent capacitor CB of the modeled cell MC is modeled with respect to the magnitude of the current IS. Based on the content described herein, those skilled in the art will be able to readily derive implementations for modeling the capacitance of the equivalent capacitor CB of the modeled cell MC using multiple variables, including the magnitude of the current IS and the magnitude of the voltage VMC applied to the modeled cell MC, based on the charging data of the modeled cell MC.

[0061] According to an exemplary implementation, a current-capacitance model representing the capacitance of the equivalent capacitor CB of the modeled cell MC based on the current IS can be derived from the charging data of the modeled cell MC. The current-capacitance model can be derived based on data modeling of the capacitance of the equivalent capacitor CB for each modeled cell MC and the magnitude of the current IS applied to the modeled cell MC. Such data modeling can be performed using regression analysis methods, such as linear regression, multinomial regression, logistic regression, and multiple regression, but is not limited to these. Figure 5 It shows a graph of the current-capacitance model derived in P120.

[0062] At this point, in order to derive the current-capacitance model, the charging data of the modeling cell MC collected in P110 can be repeatedly performed on multiple different modeling cell MCs. Accordingly, the current-capacitance model in P120 can be derived based on the charging data collected from the multiple modeling cell MCs.

[0063] Next, refer to Figure 1 and Figure 5 In P130, an MSCC charging scheme can be generated based on a current-capacitance model. Generating the MSCC charging scheme can include: determining the number of steps in the MSCC charging scheme and the current magnitude of each step based on the following first formula, such that the number of steps and the current magnitude of each step satisfy a minimum charging time condition. Therefore, the MSCC charging scheme includes the number of MSCC charging steps and the current magnitude of each step in the MSCC charging process.

[0064] [First Formula]

[0065] Here, t n I is the duration of the nth step of MSCC charging. n It is the magnitude of the current IS in the nth step of MSCC charging, V MCn The magnitude of the voltage VMC applied to the modeled cell MC at the end of the nth step of MSCC charging, V Rn The magnitude of the voltage VRB applied to the equivalent resistor RB of the modeling cell MC during the nth step of MSCC charging, C b (I n The magnitude of the current IS in the nth step of MSCC charging is I. n The capacitance of the equivalent capacitor CB is determined based on the current-capacitance model, and n is an integer greater than or equal to 1.

[0066] V Rn The following second formula is satisfied.

[0067] [Second Formula]

[0068] Here, R B It is the resistance value of the equivalent resistor RB in the modeled battery cell MC.

[0069] V n Vn is equal to the voltage VCB applied to the equivalent capacitor CB of the modeling cell MC at the beginning of the nth step of MSCC charging. Vn satisfies the following third formula.

[0070] [Third Formula]

[0071] Here, V MCn-1 It is the voltage applied to the modeled cell MC at the end of the (n-1)th step of MSCC charging, and I n-1This is the magnitude of the current IS in the (n-1)th step of MSCC charging. When n=1, I0 is typically 0, and V... MC0 It can be 0 or have a non-zero initial voltage.

[0072] The MSCC charging scheme can be determined, for example, through optimization methods. An example of an optimization method is SLSQP (Sequential Least Squares Programming). SLSQP is an optimization algorithm for solving nonlinear programming problems with equality and inequality constraints. SLSQP works by linearizing the objective function and constraints at each iteration and then solving this linearized problem. This method uses a quasi-Newton method to approximate the Hessian matrix of the Lagrangian function, thereby improving the convergence rate. SLSQP can be implemented using the optimization module of Python's SciPy library, as shown in the following code: res = minimize (func, x0, method='SLSQP', bounds=bnds, constraints=cons) print('Optimal solution:', res.x) print('Minimum value:', res.fun) Optimal solution: [61.08 50.79856993 42.87768134 36.5899862631.40140849 27.00740182 23.22887954 19.9528082 17.10314354 14.6243291412.4728853 10.61208643 9.00915843 7.634] Minimum value: 356.1335555839794 Func is the charging time to be minimized, x0 includes the condition for the magnitude of the current IS in the first step, Bnds are the constraints on the current range, and CONSTRAINTS are the boundary conditions for the simulation. The boundary condition is: in each step of MSCC charging, the magnitude of the current IS in the later step is less than the magnitude of the current IS in the previous step.

[0073] The optimal solution represents the current magnitude of each of the 14 steps in an MSCC charge. The minimum value is an indicator representing the charging time in arbitrary units. This indicator is not the actual measured time, but rather has a value proportional to the time required according to the simulation.

[0074] Figure 6 The diagram shows the current at each step of a MSCC charging scheme that satisfies the shortest charging time condition, for 10 scenarios involving 5 to 14 steps. The unit of current is mA.

[0075] (Second Implementation) Figure 7 This is a flowchart illustrating a method for manufacturing a secondary battery according to an exemplary embodiment.

[0076] Figure 8 This is a diagram illustrating a secondary battery manufacturing facility 100 according to an exemplary embodiment.

[0077] Figure 9 The measurement time required for MSCC charging is shown for schemes involving 5 to 14 steps that meet the minimum charging time conditions for MSCC.

[0078] Reference Figure 7 and Figure 8 In P100, a scheme for MSCC charging can be generated. The MSCC charging scheme can be compared with a reference... Figure 1 The method described on pages 110 to 130 is essentially the same as that described on pages 110 to 130.

[0079] Next, refer to Figure 7 and Figure 9 Multiple battery cells (BC1, BC2, ..., BCN) can be charged using an MSCC charging scheme. These multiple battery cells (BC1, BC2, ..., BCN) can be charged by the secondary battery manufacturing facility 100.

[0080] The plurality of battery cells (BC1, BC2, ..., BCN) can be connected to the plurality of modeled cells (MC, see Figure 2 The manufacturing process is basically the same as that used for the manufacturing of the multiple battery cells (BC1, BC2, ..., BCN). The multiple battery cells can have the same characteristics as the multiple modeled cells (MC, see...). Figure 2 The specifications are similar to those of the multiple modeling cells (MC, see...). Figure 2The current-capacitance model derived from the charging data can also be applied to the multiple battery cells (BC1, BC2, ..., BCN), and based on the multiple modeled cells (MC, see...). Figure 2 The MSCC charging scheme generated by the current-capacitance model can also meet the minimum charging time conditions for the multiple battery cells (BC1, BC2, ..., BCN).

[0081] The charging data of the modeled battery cell (MC) is collected for independent charging. Figure 2 Unlike other methods, the plurality of battery cells (BC1, BC2, ..., BCN) can be charged at least partially simultaneously. The secondary battery manufacturing facility 100 may include: a variable current source 110 for simultaneously charging at least partially the plurality of battery cells (BC1, BC2, ..., BCN); and a plurality of switching elements (SW11, SW12, SW21, SW22, ..., SWN1, SWN2) configured to connect the plurality of battery cells (BC1, BC2, ..., BCN) in series and provide an electrical path to bypass some of the battery cells (BC1, BC2, ..., BCN).

[0082] For example, switching element SW11 can provide or block an electrical path for charging battery cell BC1. In a specific step of the MSCC charging scheme, when battery cell BC1 is fully charged before some other battery cells (BC2, ..., BCN), switching element SW12 can provide a path to bypass battery cell BC1.

[0083] More specifically, when a specific step of the MSCC charging scheme begins, the switching elements (SW11, SW21, ..., SWN1) can be in the ON state, while the switching elements (SW12, SW22, ..., SWN2) can be in the OFF state. Therefore, the multiple battery cells (BC1, BC2, ..., BCN) connected in series can be charged by the variable current source 110.

[0084] Due to manufacturing tolerances (i.e., tolerances) and charging environment tolerances, not all battery cells in the plurality of battery cells (BC1, BC2, ..., BCN) have the same characteristics. Therefore, some of the battery cells in the plurality of battery cells (BC1, BC2, ..., BCN) are charged first, while others in the plurality of battery cells (BC1, BC2, ..., BCN) are charged subsequently.

[0085] For example, when battery cell BC1 is charged first, switching element SW11 switches from the ON state to the OFF state, and switching element SW12 switches from the OFF state to the ON state, thereby terminating the charging of battery cell BC1 and providing a bypass path including switching element SW12. Therefore, each battery cell in the plurality of battery cells (BC2, ..., BCN) can be charged until each battery cell in the plurality of battery cells (BC2, ..., BCN) reaches the charging voltage of a specific step in MSCC charging. The above operation of the plurality of switching elements (SW11, SW12, SW21, SW22, ..., SWN1, SWN2) can be repeated in a similar manner until all charging cells in the plurality of battery cells (BC1, BC2, ..., BCN) are charged. After all battery cells in the plurality of battery cells (BC1, BC2, ..., BCN) reach the charging voltage of a specific step in MSCC charging, the current for the next step of MSCC charging can be applied.

[0086] Due to various delays, including those from these switching operations, additional delay time is required as the number of MSCC charging steps increases. (See reference...) Figure 9 It has been confirmed that as the number of steps increases, the time required for MSCC charging itself decreases. However, due to the cumulative effect of additional delays caused by the increased number of steps, it has been confirmed that the MSCC charging time is shortest when it includes 7 to 8 steps.

[0087] According to an exemplary embodiment, a scheme for MSCC charging with minimum charging time conditions can be generated, thereby allowing MSCC-based series charging as described below. Typically, since the voltage of each battery cell is at a few volts, significant energy loss occurs during MSCV (Multi-Stage Constant Voltage) charging due to voltage drop caused by commercial voltage. According to the exemplary embodiment, MSCC charging is performed by connecting multiple battery cells in series, eliminating the need for voltage conversion and thus avoiding energy loss due to voltage conversion. Furthermore, since the multiple battery cells connected in series are charged based on an MSCC charging scheme that meets minimum charging time conditions, the throughput of secondary battery manufacturing can be increased.

[0088] Furthermore, the MSCC step can be determined based on additional constraints, such as the current magnitude of the first step determined by the mass of the CEI (Cathode Electrolyte Interphase) layer and the SEI (Solid Electrolyte Interphase) layer, and the charging time at a specific voltage level for the energy expression of a specific active material.

[0089] The present disclosure has been described in more detail above with reference to the accompanying drawings and embodiments. However, it should be understood that the configurations shown in the drawings or the embodiments described herein are merely one embodiment of the present disclosure and do not represent all technical concepts of the present disclosure. Furthermore, at the time of filing this application, various equivalent solutions and modifications may exist that can replace them.

Claims

1. A method for generating MSCC charging, characterized in that, The method includes: The modeled battery cell is charged to collect charging data of the modeled battery cell. Based on the charging data, a current-capacitance model is derived, and A scheme for MSCC charging is generated based on the current-capacitance model.

2. The method for generating MSCC charging according to claim 1, characterized in that, The scheme includes the number of steps in the MSCC charging process.

3. The method for generating MSCC charging according to claim 2, characterized in that, The scheme includes the magnitude of the current in each step of the MSCC charging process.

4. The method for generating MSCC charging according to claim 1, characterized in that, The current-capacitance model represents the correspondence between the magnitude of the current applied to the modeled battery cell and the capacitance of the equivalent capacitor of the modeled battery cell.

5. The method for generating MSCC charging according to claim 1, characterized in that, The scheme is also generated based on the following first formula, wherein, [First Formula] wherein t n is the duration of the n-th step of the MSCC charging, I n is the current magnitude of the n-th step of the MSCC charging, V MCn is the voltage magnitude applied to the modeled cell at the end of the n-th step of the MSCC charging, V Rn is the voltage magnitude applied to the equivalent resistor of the modeled cell in the n-th step of the MSCC charging, V n is the voltage magnitude applied to the equivalent capacitor of the modeled cell at the beginning of the n-th step of the MSCC charging, C b (I n ) is the capacitance of the equivalent capacitor of the modeled cell determined based on the current-capacitance model when the current magnitude of the n-th step of the MSCC charging is I n , and n is an integer greater than or equal to 1.

6. The method for generating MSCC charging according to claim 5, characterized in that, V Rn The following second formula is satisfied, where [Second Formula] Among them, R B It is the resistance value of the equivalent resistor of the modeled battery cell.

7. The method for generating MSCC charging according to claim 6, characterized in that, V n The following third formula is satisfied, where [Third Formula] Among them, V MCn-1 The voltage applied to the modeled cell at the end of the (n-1)th step of the MSCC charging process, and I n-1 It is the current magnitude of the (n-1)th step of the MSCC charging process.

8. The method for generating MSCC charging according to claim 7, characterized in that, The scheme is determined using SLSQP.

9. The method for generating MSCC charging according to claim 8, characterized in that, The SLSQP includes conditions that minimize the charging time of the MSCC according to the scheme.

10. The method for generating MSCC charging according to claim 8, characterized in that, The magnitude of the current in each step of the MSCC charging process in the scheme is greater than the magnitude of the current in subsequent steps of the MSCC charging process in the scheme.

11. A method for manufacturing a secondary battery, characterized in that, The method includes: Scheme for generating MSCC charging, and The above scheme is used to charge multiple battery cells, which are connected in series.

12. The method for manufacturing a secondary battery according to claim 11, characterized in that, The proposed scheme is generated based on the current-capacitance model, and The current-capacitance model represents the correspondence between the magnitude of the current applied to the modeled cell and the capacitance of the equivalent capacitor of the modeled cell.

13. The method for manufacturing a secondary battery according to claim 12, characterized in that, The modeled cell is manufactured using the same manufacturing process as the manufacturing process of the plurality of said battery cells.

14. The method for manufacturing a secondary battery according to claim 11, characterized in that, The scheme includes the number of steps in the MSCC charging process.

15. The method for manufacturing a secondary battery according to claim 12, characterized in that, The scheme includes the magnitude of the current in each step of the MSCC charging process.

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