Battery charging control method, device, and storage medium

Abstract

A battery charging control method, a device, and a storage medium. A charging interval is divided into a plurality of charging sub-intervals; and for an objective function of a total charging duration, within which a battery is charged from an initial charge state to a target charge state, with respect to the temperatures of the charging sub-intervals, by using a minimum total charging duration as an objective, and using a maximum allowable charging rate of the battery or a maximum allowable temperature of the battery representing a lithium precipitation safety threshold of the battery under different charge states and temperature conditions as a constraint condition, the solution of the objective function is optimized. The temperature rise of the battery is reduced while the charging duration is minimized, thereby avoiding lithium plating during charging of the battery and improving the charging safety.

Description

Battery charging control method, device and storage medium

[0001] This application claims priority to the Chinese patent application No. 202410609300.3, filed on May 16, 2024, to the Chinese Patent Office, the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to battery charging technology, for example, to a battery charging control method, device and storage medium. BACKGROUND

[0003] At present, the charging method of rechargeable batteries mostly adopts constant current and constant voltage charging, that is, the charging process is roughly divided into two stages. In the first stage, the battery is charged with a constant large current, and the charging voltage gradually increases. When the charging voltage reaches a predetermined value, the second stage is entered, and the battery is charged with a constant voltage, and the charging current gradually decreases until the charging current is less than a preset value, and the charging is completed.

[0004] The charging time of the conventional charging method is too long, which cannot meet the fast charging needs of users. If a large current is used for fast charging throughout the process, although the charging time can be shortened, the rapid charging will cause the rapid rise of the battery temperature, causing irreversible damage to the battery, and even causing the battery to catch fire. SUMMARY

[0005] The present application provides a battery charging control method, device and storage medium to shorten the charging time, reduce the temperature rise of the battery, and improve the charging safety.

[0006] In a first aspect, the present application provides a battery charging control method, comprising: obtaining an initial state of charge of a battery and a target state of charge set by a user, determining a charging interval constituted by the initial state of charge and the target state of charge; dividing the charging interval into a plurality of charging subintervals; for each charging subinterval, constructing a relationship function between the charging current of the charging subinterval and the temperature of the charging subinterval, and a relationship function between the charging time of the charging subinterval and the temperature of the charging subinterval, and determining a target function of the total charging time of the battery from the initial state of charge to the target state of charge with respect to the temperature of each charging subinterval; for the target function, taking the shortest total charging time as the target, and taking the maximum allowable charging rate of the battery or the maximum allowable temperature of the battery as the constraint condition, calculating the charging current of each charging subinterval; charging the battery according to the charging current of each charging subinterval.

[0007] In a second aspect, the present application provides a battery charging control device, comprising: a charging interval determination module configured to obtain an initial state of charge of a battery and a target state of charge set by a user, and determine a charging interval constituted by the initial state of charge and the target state of charge; an interval division module configured to divide the charging interval into a plurality of charging subintervals; a function construction module configured to, for each of the charging subintervals, construct a function of a charging current of the charging subinterval with respect to a temperature of the charging subinterval, and a function of a charging time of the charging subinterval with respect to the temperature of the charging subinterval, and determine a target function of the total charging time of the battery from the initial state of charge to the target state of charge with respect to the temperature of each of the charging subintervals; an optimization calculation module configured to, for the target function, calculate the charging current of each of the charging subintervals with the shortest total charging time as a target and the maximum allowable charging rate of the battery or the maximum allowable temperature of the battery as a constraint condition; and a charging control module configured to charge the battery according to the charging current of each of the charging subintervals.

[0008] In a third aspect, the present application provides an electronic device, comprising: one or more processors; a storage device configured to store 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 the battery charging control method provided in the first aspect of the present application.

[0009] In a fourth aspect, the present application provides a computer-readable storage medium, having a computer program stored thereon, and the computer program, when executed by a processor, implements the battery charging control method provided in the first aspect of the present application.

[0010] In a fifth aspect, the present application provides a computer program product, comprising a computer program, and the computer program, when executed by a processor, implements the battery charging control method provided in the first aspect of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0011] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some of the drawings of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0012] FIG. 1 is a flowchart of a battery charging control method provided in an embodiment of the present application;

[0013] FIG. 2 is a diagram illustrating the division of a charging interval provided in an embodiment of the present application;

[0014] FIG. 3 is a table of maximum allowable charging rate at different temperatures and state of charge provided by an embodiment of the present application;

[0015] FIG. 4 is a flow chart of another battery charging control method provided by an embodiment of the present application;

[0016] FIG. 5 is a curve of charging current versus state of charge provided by an embodiment of the present application;

[0017] FIG. 6 is a comparison between a curve of charging current versus charging time provided by an embodiment of the present application and a curve of charging current versus charging time of the related art;

[0018] FIG. 7 is a comparison between a curve of state of charge versus charging time provided by an embodiment of the present application and a curve of state of charge versus charging time of the related art;

[0019] FIG. 8 is a comparison between a curve of temperature versus charging time provided by an embodiment of the present application and a curve of temperature versus charging time of the related art;

[0020] FIG. 9 is a structural schematic diagram of a battery charging control device provided by an embodiment of the present application;

[0021] FIG. 10 is a structural schematic diagram of an electronic device provided by an embodiment of the present application.

[0022] The specific embodiments of the present application have been shown through the above-described drawings, and will be described in more detail hereinafter. The drawings and the written description are not intended to limit the scope of the present application in any way, but to explain the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0023] In order to make the present application more intelligible, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without any creative work should fall within the scope of protection of the present application.

[0024] It should be noted that the terms "first", "second", and the like in the description and in the claims of the present application and the above-described accompanying drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or a chronological sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or device that includes a series of steps or units does not necessarily have to be limited to only those steps or units clearly listed, but can include other steps or units that are not clearly listed or inherent to such a process, method, product, or device.

[0025] The embodiment of the present application provides a battery charging control method, including: obtaining an initial state of charge of a battery and a target state of charge set by a user, determining a charging interval composed of the initial state of charge and the target state of charge, dividing the charging interval into a plurality of charging subintervals, for each charging subinterval, constructing a relationship function of a charging current of the charging subinterval and a temperature of the charging subinterval, and a relationship function of a charging time of the charging subinterval with respect to the temperature of the charging subinterval, and determining a target function of the total charging time of the battery from the initial state of charge to the target state of charge with respect to the temperature of each charging subinterval, for the target function, taking the shortest total charging time as a target, taking the maximum allowable charging rate of the battery or the maximum allowable temperature of the battery as a constraint condition, calculating the charging current of each charging subinterval, and charging the battery according to the charging current of each charging subinterval.

[0026] The battery charging control method provided by the embodiment of the present application divides the charging interval into a plurality of charging subintervals, takes the target function of the total charging time of the battery from the initial state of charge to the target state of charge with respect to the temperature of each charging subinterval, takes the shortest total charging time as a target, and optimizes the solution of the target function by taking the maximum allowable charging rate of the battery or the maximum allowable temperature of the battery representing the lithium precipitation safety boundary of the battery under different states of charge and temperature conditions as a constraint condition, on the basis of the shortest charging time, reduces the temperature rise of the battery, avoids lithium precipitation of the battery during charging, and improves the charging safety.

[0027] The following will be described in conjunction with FIG. 1. FIG. 1 is a flowchart of a battery charging control method provided by an embodiment of the present application, the embodiment optimizes the charging current to achieve the purpose of shortening the charging time, the method can be executed by a battery charging control device provided by the embodiment of the present application, the device can be realized by software and / or hardware, and is usually configured in an electronic device, as shown in FIG. 1, the battery charging control method includes the following steps:

[0028] S101, acquire an initial state of charge of the battery currently and a target state of charge set by a user, and determine a charging interval composed of the initial state of charge and the target state of charge.

[0029] In the embodiment of the application, the battery can be a power battery for powering a vehicle, or can be other rechargeable battery, which is not limited in the embodiment of the application. In the embodiment of the application, the battery management system of the battery can detect whether the battery is connected to the charging interface, and when detecting that the battery is connected to the charging interface, acquire an initial state of charge SOC(0) of the battery currently and a target state of charge SOC(1) set by a user, and determine a charging interval composed of the initial state of charge SOC(0) and the target state of charge SOC(1) (i.e. a charging interval between the initial state of charge SOC(0) and the target state of charge SOC(1)). Exemplarily, the target state of charge SOC(1) can be a state of charge set by the user each time of charging, or can be a state of charge preset when the battery is shipped, which is not limited in the embodiment of the application.

[0030] S102, divide the charging interval into a plurality of charging subintervals.

[0031] FIG. 2 is a schematic diagram of a charging interval provided by an embodiment of the application, as shown in FIG. 2, the curve in the figure represents a change curve of a charging current with respect to a state of charge of a battery in a process of charging the battery from an initial state of charge SOC(0) to a target state of charge SOC(1) in the related art. In the embodiment of the application, the charging interval composed of the initial state of charge SOC(0) and the target state of charge SOC(1) is divided into a plurality of charging subintervals. In the embodiment of the application, the increase amount ΔSOC(i) of the state of charge of each charging subinterval can be the same, i.e. the charging interval is divided into a plurality of charging subintervals at equal intervals, and the increase amount of the state of charge of each charging subinterval is ΔSOC. It should be noted that in some other embodiments of the application, the increase amount of the state of charge of each charging subinterval ΔSOC(i) can also be different, which is not limited in the embodiment of the application.

[0032] S103, for each charging subinterval, construct a function relationship between a charging current of the charging subinterval and a temperature of the charging subinterval, and a function relationship between a charging time of the charging subinterval and the temperature of the charging subinterval, and determine a target function of a total charging time of the battery from the initial state of charge to the target state of charge with respect to the temperature of each charging subinterval.

[0033] In the embodiments of the present application, for each charging subinterval, a function relationship between the charging current I(i) of the charging subinterval and the temperature of the charging subinterval is constructed, and a function relationship between the charging time t(i) of the charging subinterval and the temperature of the charging subinterval is constructed, and then the function relationship between the charging time t(i) of each charging subinterval and the temperature of the charging subinterval is accumulated to determine a target function of the total charging time of the battery from the initial state of charge SOC(0) to the target state of charge SOC(1) with respect to the temperature of each charging subinterval.

[0034] In some embodiments of the present application, the increase of the state of charge of the charging subinterval ΔSOC(i) is very small, that is, the entire charging interval is divided into a very large number of charging subintervals, and therefore it can be considered that the charging current I(i) of each charging subinterval is constant, that is, a constant value.

[0035] The above step S103 includes the following substeps:

[0036] S1031, constructing a first expression reflecting the relationship between the charging time of the charging subinterval and the charging current of the charging subinterval.

[0037] As described above, the charging current I(i) of each charging subinterval is a constant value, and therefore the first expression reflecting the relationship between the charging time t(i) of the charging subinterval and the charging current I(i) of the charging subinterval can be constructed with the charging current I(i) as a variable and the total capacity of the battery and the increase of the state of charge of the charging subinterval ΔSOC(i) as known parameters. For example, the first expression is as follows:

[0038] Wherein, Cap is the total capacity of the battery.

[0039] S1032, constructing a second expression reflecting the relationship between the heat absorption of the battery and the charging current of the charging subinterval, the charging time of the charging subinterval and the temperature of the charging subinterval based on the heat balance relationship when the battery generates heat.

[0040] The battery generates heat during charging, and part of the generated heat is absorbed by the battery itself, causing the battery temperature to rise, and the other part is dissipated, constituting a heat balance. Therefore, the second expression reflecting the relationship between the heat absorption of the battery and the charging current of the charging subinterval, the charging time of the charging subinterval and the temperature of the charging subinterval can be constructed based on the heat balance relationship when the battery generates heat.

[0041] Wherein, the heat generation of the battery is mainly the current of the battery doing work on the internal resistance of the battery, and therefore the heat generation power of the battery is calculated according to the Bernardi formula, and therefore the heat generation of the battery in the i-th charging subinterval is:

[0042] wherein Q g(i) is the heat generation of the battery in the i-th charging subinterval, T(i) is the end temperature of the end position of the i-th charging subinterval, is the derivative of the charging voltage with respect to the temperature in the i-th charging subinterval.

[0043] The calculation formula of the heat dissipation of the battery in the i-th charging subinterval is as follows: Q o(i) = P(i) t(i);

[0044] wherein Q o(i) is the heat dissipation of the battery in the i-th charging subinterval, and P(i) is the heat dissipation power of the battery. The heat dissipation power of the battery depends on the heat dissipation cooling mode of the battery, which includes but is not limited to water cooling, air cooling, semiconductor refrigeration cooling, etc. in the embodiments of the present application, which are not limited herein. Exemplarily, the heat dissipation power P(i) corresponding to each charging subinterval can be determined in advance based on the heat dissipation cooling mode of the battery.

[0045] Exemplarily, in a specific embodiment of the present application, taking the heat dissipation cooling mode of the battery using liquid cooling as an example, the heat dissipation power of the battery in the i-th charging subinterval is: P(i) = R T (T(i) - Tc);

[0046] wherein R T is the overall heat transfer thermal resistance between the battery and the cooling liquid, and Tc is the temperature of the cooling liquid, which can be the inlet temperature of the cooling liquid, or the average temperature of the cooling liquid inlet and outlet, which is not limited in the embodiments of the present application.

[0047] Therefore, based on the heat balance relationship when the battery generates heat (i.e. the heat absorption of the battery is equal to the heat generation of the battery minus the heat dissipation of the battery), the second expression reflecting the relationship between the heat absorption of the battery and the charging current of the charging subinterval, the charging time of the charging subinterval and the temperature of the charging subinterval can be obtained as follows:

[0048] Q(i) is the heat absorption of the battery in the i-th charging subinterval.

[0049] In a specific embodiment of the present application, taking the heat dissipation cooling mode of the battery using liquid cooling as an example, the expression of the heat dissipation power P(i) is substituted into the above-mentioned second expression, and the second expression is obtained as follows:

[0050] S1033, constructing a third expression reflecting the relationship between the heat absorption of the battery and the temperature of the charging subinterval based on the specific heat formula.

[0051] The heat absorption amount of the battery can be calculated based on the heat balance relationship when the battery generates heat, and can also be calculated based on the temperature rise amount of the battery by using the specific heat formula. Therefore, in the embodiments of the present application, a third expression reflecting the relationship between the heat absorption amount of the battery and the temperature of the charging subinterval is constructed based on the specific heat formula. The third expression is as follows: Q(i) = (T(i) - T(i-1))C p m;

[0052] wherein T(i-1) is the starting temperature of the starting position of the i th charging subinterval, and is also the ending temperature of the ending position of the i-1 th charging subinterval, C p is the specific heat capacity of the battery, and m is the mass of the battery.

[0053] S1034, the first expression, the second expression and the third expression are combined to obtain a fourth expression of a relationship function reflecting the charging current of the charging subinterval and the temperature of the charging subinterval.

[0054] In the embodiments of the present application, the first expression, the second expression and the third expression are combined to obtain a fourth expression of a relationship function reflecting the charging current of the charging subinterval and the temperature of the charging subinterval. Specifically, the second expression and the third expression are combined to obtain a relationship between the charging time of the i th charging subinterval and the temperature of the i th charging subinterval, and the relationship is substituted into the first expression to obtain the fourth expression of the relationship function reflecting the charging current of the charging subinterval and the temperature of the charging subinterval. The fourth expression is as follows:

[0055] In a specific embodiment of the present application, taking the battery using a liquid cooling heat dissipation cooling mode as an example, the fourth expression is as follows:

[0056] S1035, the fourth expression and the first expression are combined to obtain a relationship function of the charging time of the charging subinterval with respect to the temperature of the charging subinterval.

[0057] By way of example, substituting the fourth expression described above into the first expression described above, the relationship function of the charging time of the charging subinterval with respect to the temperature of the charging subinterval is as follows:

[0058] In a specific embodiment of the present application, taking the battery using a liquid cooling heat dissipation cooling mode as an example, the relationship function of the charging time of the charging subinterval with respect to the temperature of the charging subinterval is as follows:

[0059] S1036, accumulate the relationship function of the charging time of all charging subintervals with respect to the temperature of the charging subintervals to obtain a target function of the total charging time of the battery from the initial state of charge to the target state of charge with respect to the temperature of each charging subinterval.

[0060] In the embodiments of the present application, the relationship function of the charging time of all charging subintervals with respect to the temperature of the charging subintervals is accumulated to obtain a target function of the total charging time of the battery from the initial state of charge to the target state of charge with respect to the temperature of each charging subinterval. Specifically, the target function is as follows:

[0061] wherein t(tot) is the total charging time of the battery from the initial state of charge to the target state of charge, and n is the total number of charging subintervals.

[0062] In a specific embodiment of the present application, taking the battery using a liquid cooling cooling mode as an example, the target function is as follows:

[0063] S104, for the target function, taking the shortest total charging time as the target and the maximum allowable charging rate of the battery as the constraint condition, the charging current of each charging subinterval is calculated.

[0064] In the embodiments of the present application, for the above target function, an optimization algorithm is used for optimization, taking the shortest total charging time as the target and the maximum allowable charging rate of the battery as the constraint condition, the charging current of each charging subinterval is calculated. For example, in the embodiments of the present application, the optimization algorithm can be a nonlinear optimization algorithm, a genetic algorithm optimization algorithm, etc., which is not limited in the embodiments of the present application.

[0065] In some embodiments of the present application, taking the interior point method in the nonlinear optimization algorithm as an example for illustration, the above step S104 includes the following substeps:

[0066] S1041, pre-charge the battery at different states of charge at different temperatures to obtain the maximum allowable charging rate.

[0067] The charging rate is a measure of the speed of battery charging, which refers to the current value required by the battery to charge to its rated capacity within a specified time. It is equal to the rated capacity of the battery in numerical value, i.e. charging current / battery rated capacity=charging rate.

[0068] Exemplarily, in the embodiment of the present application, an electrochemical model of the battery can be established in advance, and the maximum allowable charging rate at different temperatures and states of charge, i.e., the lithium precipitation safety boundary of the battery, can be determined based on the electrochemical model to form a state of charge-temperature-maximum allowable charging rate table. When the charging rate under a certain state of charge and temperature condition is greater than the maximum allowable charging rate under the condition, the lithium precipitation phenomenon occurs in the battery. The lithium precipitation phenomenon refers to an abnormal phenomenon that lithium ions are not embedded in the negative electrode material on the negative electrode side during the charging process of the lithium ion battery, but are precipitated in the form of metal lithium on the negative electrode surface. The metal lithium is usually precipitated in the form of lithium dendrites, and the excessively grown lithium dendrites can pierce the separator, leading to positive and negative electrode short circuit, and even cause fire and explosion of the lithium ion battery. FIG. 3 is a table of the maximum allowable charging rate measured at different temperatures and states of charge provided by the embodiment of the present application. Exemplarily, as shown in FIG. 3, the maximum allowable charging rate of the battery under the condition of a state of charge of 50% and 20°C is 2.5C.

[0069] S1042, determining a feasible region of the objective function with the maximum allowable charging rate as a boundary.

[0070] The maximum allowable charging rate measured at different temperatures and states of charge is taken as a boundary condition to construct the feasible region of the solution of the objective function, i.e., the solution of the objective function can only take values within the feasible region.

[0071] S1043, selecting a feasible solution within the feasible region to assign an initial value to the temperature of each charging subinterval.

[0072] In the embodiment of the present application, a solution is randomly selected within the feasible region as a feasible solution, and the feasible solution is an array composed of the temperatures of each charging subinterval. In this way, an initial value is assigned to the temperature of each charging subinterval.

[0073] S1044, judging whether the feasible solution is an optimal solution.

[0074] In the embodiment of the present application, the gradient descent iterative search method is adopted to search in multiple search directions within the feasible region from the initial feasible solution along the search direction. When the search direction coincides with the direction of the maximum gradient descent, the feasible solution is iteratively updated along the direction of the maximum gradient descent, and the update is stopped until there is no maximum gradient direction, i.e., the current feasible solution is determined to be the optimal solution; at this time t(tot) T <t(tot) T+1 , t(tot) T+1 represents the value of the objective function under the search direction, and t(tot) T represents the value of the objective function of the current feasible solution. Among them, the direction of the maximum gradient descent is the direction with the fastest descent speed of the objective function, and the search direction is the moving direction searched within the feasible region from the current feasible solution.

[0075] Of course, the iteration can also be terminated when the difference between the objective function value of the current feasible solution and the updated objective function in the search direction is less than or equal to a preset value ε, and the current feasible solution is the optimal solution, i.e. t(tot) T -t(tot) T+1 ≤ε. For example, -0.00001≤ε≤0.

[0076] S1045, if yes, the initial value of the temperature of each charging subinterval in the feasible solution is taken as the temperature of each charging subinterval.

[0077] If the current feasible solution is the optimal solution, the initial value of the temperature of each charging subinterval in the feasible solution is taken as the temperature of each charging subinterval.

[0078] S1046, if no, the feasible solution is updated in the direction of the maximum gradient descent, and the step of judging whether the feasible solution is the optimal solution is returned to be executed until the optimal solution is obtained.

[0079] If the current feasible solution is not the optimal solution, the feasible solution is updated in the direction of the maximum gradient descent, and the step of judging whether the feasible solution (updated feasible solution) is the optimal solution is returned to be executed until the optimal solution is obtained.

[0080] S1047, based on the optimal solution of the temperature of each charging subinterval and the relationship function between the charging current of each charging subinterval and the temperature of each charging subinterval, the charging current of each charging subinterval is calculated.

[0081] After obtaining the optimal solution of the temperature of each charging subinterval, the temperature of each charging subinterval is substituted into the fourth expression reflecting the relationship function between the charging current of each charging subinterval and the temperature of each charging subinterval, and the charging current of each charging subinterval can be obtained.

[0082] S105, the battery is charged according to the charging current of each charging subinterval.

[0083] After the charging current of each charging subinterval is calculated, the battery is charged according to the charging current of each charging subinterval.

[0084] The battery charging control method provided in the embodiments of the present application obtains the initial state of charge and the target state of charge set by the user, determines a charging interval composed of the initial state of charge and the target state of charge, divides the charging interval into a plurality of charging subintervals, for each charging subinterval, constructs a function of the charging current of the charging subinterval and the temperature of the charging subinterval, and a function of the charging time of the charging subinterval with respect to the temperature of the charging subinterval, and determines a target function of the total charging time of the battery from the initial state of charge to the target state of charge with respect to the temperature of each charging subinterval. For the target function, the shortest total charging time is taken as the target, and the maximum allowable charging rate of the battery is taken as the constraint condition to calculate the charging current of each charging subinterval, and the battery is charged according to the charging current of each charging subinterval. In the present application, the charging interval is divided into a plurality of charging subintervals, the target function of the total charging time of the battery from the initial state of charge to the target state of charge with respect to the temperature of each charging subinterval is determined, the shortest total charging time is taken as the target, and the maximum allowable charging rate of the battery under different states of charge and temperature conditions representing the lithium precipitation safety boundary of the battery is taken as the constraint condition to optimize the solution of the target function. On the basis of the shortest charging time, the temperature rise of the battery is reduced, the lithium precipitation of the battery during charging is avoided, and the charging safety is improved.

[0085] The above embodiments take the maximum allowable charging rate of the battery as the constraint condition of the target function, and optimize the target function as an example. FIG. 4 is a flowchart of another battery charging control method provided in the embodiments of the present application. In this embodiment, the target function can also be optimized with the maximum allowable temperature of the battery as the constraint condition. As shown in FIG. 4, the embodiment includes the following steps:

[0086] S201, obtaining the initial state of charge and the target state of charge set by the user, and determining a charging interval composed of the initial state of charge and the target state of charge.

[0087] In the embodiments of the present application, the battery can be a power battery for providing power for a vehicle, or can be other rechargeable batteries, which are not limited in the embodiments of the present application. In the embodiments of the present application, the battery management system of the battery can detect whether the battery is connected to a charging interface. When it is detected that the battery is connected to the charging interface, the initial state of charge SOC(0) of the battery and the target state of charge SOC(1) set by the user are obtained, and a charging interval composed of the initial state of charge SOC(0) and the target state of charge SOC(1) (i.e. the charging interval between the initial state of charge SOC(0) and the target state of charge SOC(1)) is determined. Exemplarily, the target state of charge SOC(1) can be the state of charge set by the user each time of charging, or can be the state of charge preset when the battery is shipped, which are not limited in the embodiments of the present application.

[0088] S202. Divide the charging interval into multiple charging sub-intervals.

[0089] For example, as shown in FIG. 2, the curve represents the change of the charging current with the state of charge of the battery during the process of charging the battery from the initial state of charge SOC(0) to the target state of charge SOC(1) in the related art. In the embodiments of the present application, the charging interval composed of the initial state of charge SOC(0) and the target state of charge SOC(1) is divided into multiple charging sub-intervals. In the embodiments of the present application, the increase of the state of charge of each charging sub-interval ΔSOC(i) can be the same, i.e., the charging interval is divided into multiple charging sub-intervals at equal intervals. It should be noted that in some other embodiments of the present application, the increase of the state of charge of each charging sub-interval ΔSOC(i) can also be different, which is not limited in the embodiments of the present application.

[0090] S203. For each charging sub-interval, construct a function of the charging current of the charging sub-interval and the temperature of the charging sub-interval, and a function of the charging time of the charging sub-interval with respect to the temperature of the charging sub-interval, and determine a target function of the total charging time of the battery from the initial state of charge to the target state of charge with respect to the temperature of each charging sub-interval.

[0091] In the embodiments of the present application, for each charging sub-interval, a function of the charging current I(i) of the charging sub-interval and the temperature of the charging sub-interval, and a function of the charging time t(i) of the charging sub-interval with respect to the temperature of the charging sub-interval are constructed, and then the functions of the charging time t(i) of each charging sub-interval with respect to the temperature of the charging sub-interval are accumulated to determine a target function of the total charging time of the battery from the initial state of charge SOC(0) to the target state of charge SOC(1) with respect to the temperature of each charging sub-interval. Specifically, the process of constructing the target function has been described in detail in the foregoing embodiments, which will not be described herein again.

[0092] In some embodiments of the present application, the increase of the state of charge of each charging sub-interval ΔSOC(i) is very small, i.e., the entire charging interval is divided into a very large number of charging sub-intervals, and therefore the charging current I(i) of each charging sub-interval can be considered as constant.

[0093] S204. For the target function, the charging current of each charging sub-interval is calculated with the shortest total charging time as the target and the maximum allowable temperature of the battery as the constraint condition.

[0094] In the embodiments of the present application, for the above target function, an optimization algorithm is used for optimization, to calculate the charging current of each charging subinterval, with the shortest total charging time as the target and the maximum allowable temperature of the battery as the constraint condition. For example, in the embodiments of the present application, the optimization algorithm can be a nonlinear optimization algorithm, a genetic algorithm optimization algorithm, etc., which are not limited in the embodiments of the present application.

[0095] In some embodiments of the present application, the interior point method in the nonlinear optimization algorithm is taken as an example for illustration, and the above step S204 includes the following substeps:

[0096] S2041, pre-charging the battery at different states of charge at different charging rates to obtain the maximum allowable temperature.

[0097] For example, in the embodiments of the present application, an electrochemical model of the battery can be pre-established, and the maximum allowable temperature at different charging rates and states of charge, i.e., the lithium precipitation safety boundary of the battery, can be determined based on the electrochemical model, to form a state of charge-temperature-maximum allowable charging rate table.

[0098] S2042, determining the feasible region of the target function with the maximum allowable temperature as the boundary.

[0099] The maximum allowable temperature measured at the above different temperatures and states of charge is used as the boundary condition to construct the feasible region of the solution of the target function, i.e., the solution of the target function can only take values within the feasible region.

[0100] S2043, selecting a feasible solution within the feasible region to assign an initial value to the charging current of each charging subinterval.

[0101] In the embodiments of the present application, a solution is randomly selected within the feasible region as the feasible solution, and the feasible solution is an array composed of the charging currents of each charging subinterval, so that an initial value is assigned to the charging current of each charging subinterval.

[0102] S2044, judging whether the feasible solution is the optimal solution.

[0103] In the embodiments of the present application, the gradient descent iterative search method is used to search in multiple search directions within the feasible region from the initial feasible solution along the search direction, and when the search direction coincides with the direction of the maximum gradient descent, the feasible solution is iteratively updated along the direction of the maximum gradient descent, until there is no maximum gradient direction for updating, i.e., the current feasible solution is determined to be the optimal solution; at this time t(tot) I <t(tot) I+1 , t(tot) I+1 represents the target function value in the search direction, t(tot) IThe target function value representing the current feasible solution. Wherein, the direction of the maximum gradient descent is the direction of the fastest descent speed of the target function, and the search direction is the moving direction of searching in the feasible region from the current feasible solution.

[0104] Of course, the iteration can also be terminated when the difference between the target function value of the current feasible solution and the updated target function of the search direction is less than or equal to a certain preset value ε, and the current feasible solution is the optimal solution at this time, that is, t(tot) I -t(tot) I+1 ≤ε. Exemplarily, -0.00001≤ε≤0.

[0105] S2045, if yes, the initial value of the charging current of each charging subinterval in the feasible solution is taken as the charging current of each charging subinterval.

[0106] If the current feasible solution is the optimal solution, the initial value of the charging current of each charging subinterval in the feasible solution is taken as the charging current of each charging subinterval.

[0107] S2046, if no, the feasible solution is updated according to the direction of the maximum gradient descent, and the step of judging whether the feasible solution is the optimal solution is returned to be executed until the optimal solution is obtained.

[0108] If the current feasible solution is not the optimal solution, the feasible solution is updated according to the direction of the maximum gradient descent, and the step of judging whether the feasible solution (updated feasible solution) is the optimal solution is returned to be executed until the optimal solution is obtained.

[0109] After obtaining the charging current of each charging subinterval, the charging current of the first charging subinterval can be substituted into the fourth expression in the above embodiment to obtain the end temperature T(1) of the end position of the first charging subinterval (the start temperature T(0) of the start position of the first charging subinterval is known), and then T(1) is taken as the start temperature of the start position of the second charging subinterval, and the charging current of the second charging subinterval is substituted into the fourth expression in the above embodiment to obtain the end temperature T(2) of the end position of the second charging subinterval. The above process is repeated to obtain the end temperature of the end position of each charging subinterval.

[0110] In the above embodiment, the construction and optimization process of the function are both executed online, and the computing resources of the vehicle infotainment system are limited. During the online execution process, delay may occur due to insufficient computing power, which affects the accurate control of the current during the charging process. Therefore, the above online execution process is difficult to apply in the infotainment system with low computing power.

[0111] In view of the above problems, the embodiments of the present application provide a simplified method to reduce the requirement for infotainment computing power.

[0112] An example of a simplified method is as follows:

[0113] 1. After calculating the charging current of each charging interval based on the temperature of the charging interval, the charging current and the state of charge of each charging interval are fitted to obtain a relationship curve of the charging current with respect to the state of charge under the initial state of charge, the target state of charge and the initial temperature.

[0114] An example is that the charging current of each charging interval is obtained by the foregoing embodiment, and then the charging current and the state of charge of each charging interval are fitted to obtain a relationship curve of the charging current with respect to the state of charge under the initial state of charge, the target state of charge and the initial temperature. An example of the fitting method is cubic spline interpolation fitting. For the same battery, the relationship curves of the charging current with respect to the state of charge under different initial states of charge, different target states of charge and different initial temperatures are obtained, so that a plurality of relationship curves are obtained. In the embodiment of the application, the relationship curve of the charging current with respect to the state of charge under the initial state of charge, the target state of charge and the initial temperature can be written into the memory of the battery management system.

[0115] 2. At the beginning of charging, the initial state of charge of the battery at present, the target state of charge set by the user and the initial temperature of the battery are obtained.

[0116] At the beginning of charging, the initial state of charge of the battery at present, the target state of charge set by the user and the initial temperature of the battery are obtained.

[0117] 3. The target relationship curve is determined based on the initial state of charge of the battery at present, the target state of charge set by the user and the initial temperature of the battery.

[0118] The target relationship curve corresponding to the initial state of charge of the battery at present, the target state of charge set by the user and the initial temperature of the battery is called from the memory of the battery management system based on the initial state of charge of the battery at present, the target state of charge set by the user and the initial temperature of the battery.

[0119] 4. During the charging process, the real-time state of charge of the battery is monitored in real time.

[0120] During the charging process, the real-time state of charge of the battery is monitored in real time.

[0121] 5. The target charging current is calculated from the target relationship curve based on the real-time state of charge.

[0122] An example is that the real-time state of charge is substituted into the equation of the target relationship curve to obtain the target charging current corresponding to the real-time state of charge.

[0123] 6. Charging the battery with a target charging current.

[0124] Charging the battery with a target charging current.

[0125] In the embodiments of the present application, the target function is constructed in advance and optimized to obtain the charging current of each charging subinterval, and then the charging current and the state of charge of each charging subinterval are fitted to obtain the relationship curve of the charging current with respect to the state of charge under the conditions of the initial state of charge, the target state of charge and the initial temperature, and the relationship curve is written into the memory of the battery management system. In actual application, only the corresponding target relationship curve is recalled from the memory of the battery management system based on the current initial state of charge of the battery, the target state of charge set by the user and the initial temperature of the battery, and then the target charging current corresponding to the real-time state of charge is found from the target relationship curve according to the real-time state of charge of the battery. The target function and the optimization process can be completed offline in advance, thus reducing the requirement for the computing power of the vehicle machine.

[0126] Exemplarily, another simplified method is as follows:

[0127] 1. After calculating the charging current of each charging subinterval based on the temperature of the charging subinterval, the charging current and the state of charge of each charging subinterval are fitted to obtain a relationship straight line of the charging current with respect to the state of charge under the conditions of the initial state of charge, the target state of charge and the initial temperature.

[0128] Exemplarily, the charging current of each charging subinterval under the conditions of the initial state of charge, the target state of charge and the initial temperature is obtained through the foregoing embodiments, and then the charging current and the state of charge of each charging subinterval are linearly fitted to obtain a relationship straight line of the charging current with respect to the state of charge under the conditions of the initial state of charge, the target state of charge and the initial temperature. For the same battery, the relationship straight line of the charging current with respect to the state of charge under different initial states of charge, different target states of charge and different initial temperatures is obtained, and thus a plurality of relationship straight lines are obtained.

[0129] 2. The slope of the relationship straight line is calculated as the charging rate slope.

[0130] In the embodiments of the present application, the slope of the relationship straight line is calculated as the charging rate slope, and the method of calculating the slope of the straight line is not described herein.

[0131] 3. The average charging rate is calculated based on the charging current corresponding to the initial state of charge and the charging current corresponding to the target state of charge on the relationship straight line.

[0132] In the embodiments of the present application, the average charging rate is calculated based on the charging current corresponding to the initial state of charge and the charging current corresponding to the target state of charge on the straight line of the relationship. Illustratively, the average value of the charging current corresponding to the initial state of charge and the charging current corresponding to the target state of charge is calculated as the average charging current, and then the average charging current is divided by the rated capacity of the battery to obtain the average charging rate.

[0133] 4. The charging rate slope and the average charging rate are written into the battery management system of the battery.

[0134] In the embodiments of the present application, the charging rate slope and the average charging rate corresponding to different initial states of charge, different target states of charge and different initial temperature conditions are written into the memory of the battery management system of the battery.

[0135] 5. At the beginning of charging, the current initial state of charge of the battery, the target state of charge set by the user and the initial temperature of the battery are obtained.

[0136] At the beginning of charging, the current initial state of charge of the battery, the target state of charge set by the user and the initial temperature of the battery are obtained.

[0137] 6. The target charging rate slope and the target average charging rate are determined based on the current initial state of charge of the battery, the target state of charge set by the user and the initial temperature of the battery.

[0138] The target charging rate slope and the target average charging rate corresponding to the current initial state of charge of the battery, the target state of charge set by the user and the initial temperature of the battery are retrieved from the memory of the battery management system.

[0139] Illustratively, a lookup table can be established based on the charging rate slope and the average charging rate corresponding to different initial states of charge, different target states of charge and different initial temperature conditions, and the target charging rate slope and the target average charging rate are written. At the beginning of charging, the target charging rate slope and the target average charging rate corresponding to the current initial state of charge of the battery, the target state of charge and the initial temperature can be found from the lookup table.

[0140] 7. During the charging process, the real-time state of charge of the battery is monitored in real time.

[0141] 8. The target charging current is calculated based on the real-time state of charge, the target charging rate slope and the target average charging rate.

[0142] In the embodiments of the present application, the target charging current is calculated based on the real-time state of charge, the target charging rate slope and the target average charging rate.

[0143] For example, the target charging current is calculated based on the real-time state of charge, the target charging rate slope and the target average charging rate, and the calculation formula is as follows:

[0144] Wherein, I(t) is the target charging current, k is the target charging rate slope, SOC is the real-time state of charge, SOC(0) is the initial state of charge, SOC(1) is the target state of charge, midSOC is the mid-value between the initial state of charge and the target state of charge, and C(avg) is the target average charging rate.

[0145] 9. Charging the battery with the target charging current.

[0146] Charging the battery with the target charging current.

[0147] The embodiments of the present application pre-construct a target function and optimize it to obtain the charging current of each charging sub-interval, then fit the charging current and the state of charge of each charging sub-interval to obtain a relationship straight line of the charging current with respect to the state of charge under the conditions of the initial state of charge, the target state of charge and the initial temperature, and determine the charging rate slope and the average charging rate corresponding to the relationship straight line, and then write the charging rate slope and the average charging rate under the conditions of the initial state of charge, the target state of charge and the initial temperature into the memory of the battery management system. In actual application, only the target charging rate slope and the target average charging rate corresponding to the initial state of charge, the target state of charge and the initial temperature of the battery are retrieved from the memory of the battery management system based on the current initial state of charge of the battery, the target state of charge set by the user and the initial temperature of the battery, and the target charging current is calculated based on the real-time state of charge, the target charging rate slope and the target average charging rate, the target function and the optimization process can be completed offline in advance, thus reducing the computing power requirement of the vehicle machine. In addition, the embodiments of the present application only need to write the array of the charging rate slope and the average charging rate under the conditions of the initial state of charge, the target state of charge and the initial temperature into the memory of the battery management system, which is simpler and has smaller storage requirement compared with writing the entire relationship curve into the memory of the battery management system in the previous simplified method, and the subsequent calculation of the relationship curve is not required, and the computing power requirement is smaller.

[0148] In some embodiments of the present application, during the charging process of the battery according to the charging current of each charging subinterval, the charging current of each charging subinterval can be corrected in consideration of the battery aging and the case that the temperature rise leads to the increase of the internal resistance of the battery, so as to avoid the problem of excessive current leading to excessive temperature rise and lithium precipitation, and improve the safety. For example, during the charging of the battery according to the charging current of each charging subinterval, the current internal resistance value of the battery is detected, and it is determined whether the current internal resistance value of the battery is greater than a preset internal resistance value. For example, the preset internal resistance value can be the factory value of the internal resistance of the battery, or can be set by the user, which is not limited in the embodiments of the present application. When the current internal resistance value of the battery is greater than the preset internal resistance value, the charging current of the charging subinterval is multiplied by a correction coefficient a to obtain a corrected current, wherein 0 < a < 1, and then the battery is charged according to the corrected current of each charging subinterval.

[0149] It should be noted that for the same battery, the charging interval can be divided in many different ways according to the number of charging subintervals, the state of charge increase of the charging subinterval, so as to obtain many different charging subinterval division methods, so as to obtain many charging current-state of charge relationship curves or relationship straight lines under the conditions of initial state of charge, target state of charge and initial temperature. The more the number of charging subintervals, the smaller the state of charge increase, the closer the charging current of the charging subinterval to the constant value, the higher the charging control accuracy, and correspondingly, the larger the calculation amount. In the embodiments of the present application, the charging control accuracy and the calculation amount can be balanced, and the appropriate relationship curve or relationship straight line can be selected for charging control.

[0150] FIG. 5 is a relationship curve of charging current and state of charge provided by an embodiment of the present application. As shown in FIG. 5, the initial state of charge of the battery is 10%, the target state of charge is 80%, and the entire charging interval is divided into 15 charging subintervals. The charging current in each charging subinterval is constant, and the charging current decreases with the increase of the state of charge.

[0151] FIG. 6 is a comparison diagram of the relationship curve of charging current and charging time provided by an embodiment of the present application and the relationship curve of charging current and charging time of the related art, and FIG. 7 is a comparison diagram of the relationship curve of state of charge and charging time provided by an embodiment of the present application and the relationship curve of state of charge and charging time of the related art. The related art uses step current charging. Before the state of charge is 70%, a constant large current is used for charging, and after the state of charge reaches 70%, the charging current gradually decreases. As shown in FIGS. 6 and 7, from the initial state of charge 10% to the target state of charge 80%, the related art needs 427 seconds, while the charging control method of the present application only needs 363 seconds, and the charging time is shortened by 64 seconds.

[0152] FIG. 8 is a comparison diagram of a temperature and charging time curve provided by an embodiment of the present application and a temperature and charging time curve of the related art. As shown in FIG. 8, the charging control method provided by the embodiment of the present application has approximately the same temperature rise performance as the related art, and the temperature rise is lower than that of the related art in most time.

[0153] An embodiment of the present application further provides a battery charging control device. FIG. 9 is a structural schematic diagram of the battery charging control device provided by an embodiment of the present application. As shown in FIG. 9, the battery charging control device comprises:

[0154] A charging interval determination module 301 is configured to acquire an initial state of charge of a battery and a target state of charge set by a user, and determine a charging interval composed of the initial state of charge and the target state of charge.

[0155] An interval division module 302 is configured to divide the charging interval into a plurality of charging subintervals.

[0156] A function construction module 303 is configured to, for each of the charging subintervals, construct a function of a charging current of the charging subinterval and a temperature of the charging subinterval, and a function of a charging time of the charging subinterval with respect to the temperature of the charging subinterval, and determine a target function of the total charging time of the battery from the initial state of charge to the target state of charge with respect to the temperature of each of the charging subintervals.

[0157] An optimization calculation module 304 is configured to, for the target function, calculate the charging current of each of the charging subintervals with the shortest total charging time as a target and the maximum allowable charging rate of the battery or the maximum allowable temperature of the battery as a constraint condition.

[0158] A charging control module 305 is configured to charge the battery according to the charging current of each of the charging subintervals.

[0159] In some embodiments of the present application, the function construction module 303 comprises:

[0160] A first expression construction sub-module is configured to make the charging current of each of the charging subintervals a constant value, and construct a first expression reflecting a relationship between the charging time of the charging subinterval and the charging current of the charging subinterval.

[0161] A second expression construction sub-module is configured to construct a second expression reflecting a relationship between a heat absorption amount of the battery and the charging current of the charging subinterval, the charging time of the charging subinterval and the temperature of the charging subinterval based on a heat balance relationship when the battery generates heat.

[0162] a third expression construction submodule configured to construct a third expression reflecting a relationship between heat absorption of the battery and temperature of the charging subinterval based on a specific heat formula;

[0163] a fourth expression construction submodule configured to obtain a fourth expression reflecting a relationship function of charging current of the charging subinterval and temperature of the charging subinterval by combining the first expression, the second expression and the third expression;

[0164] a relationship function determination submodule configured to obtain a relationship function of charging time of the charging subinterval with respect to temperature of the charging subinterval by combining the fourth expression and the first expression;

[0165] a target function determination submodule configured to obtain a target function of total charging time of the battery from the initial state of charge to the target state of charge with respect to temperature of each charging subinterval by accumulating the relationship functions of charging time of all the charging subintervals with respect to temperature of the charging subinterval.

[0166] In some embodiments of the present application, the first expression is:

[0167] the second expression is:

[0168] the third expression is: Q(i) = (T(i) - T(i-1))C p m;

[0169] wherein t(i) is charging time of the i th charging subinterval, ΔSOC(i) is state of charge change amount of the i th charging subinterval, Cap is total capacity of the battery, I(i) is charging current of the i th charging subinterval, Q(i) is heat absorption of the battery in the i th charging subinterval, R is internal resistance of the battery, T(i) is end temperature of an end position of the i th charging subinterval, T(i-1) is start temperature of a start position of the i th charging subinterval, which is also end temperature of an end position of the i-1 th charging subinterval, is derivative of charging voltage with respect to temperature in the i th charging subinterval, P(i) is heat dissipation power of the battery, C p is specific heat capacity of the battery, and m is mass of the battery.

[0170] In some embodiments of the present application, the battery is cooled by liquid cooling, and the heat dissipation power of the battery is: P(i) = R T (T(i) - Tc);

[0171] wherein R TTc is the temperature of the cooling liquid.

[0172] In some embodiments of the present application, the fourth expression is:

[0173] In some embodiments of the present application, the relationship function of the charging time of the charging sub-interval with respect to the temperature of the charging sub-interval is:

[0174] The target function of the total charging time of the battery from the initial state of charge to the target state of charge with respect to the temperature of each charging sub-interval is:

[0175] t(tot) is the total charging time of the battery from the initial state of charge to the target state of charge, and n is the total number of the charging sub-intervals.

[0176] In some embodiments of the present application, the optimization calculation module 304 comprises:

[0177] A maximum allowable charging rate determination sub-module is configured to pre-charge the battery at different states of charge at different temperatures to obtain a maximum allowable charging rate.

[0178] A first feasible region determination sub-module is configured to determine a feasible region of the target function with the maximum allowable charging rate as a boundary.

[0179] A first initial feasible solution determination sub-module is configured to select a feasible solution within the feasible region to assign an initial value to the temperature of each charging sub-interval.

[0180] A first judgment sub-module is configured to judge whether the feasible solution is an optimal solution.

[0181] A sub-interval temperature determination sub-module is configured to, when the feasible solution is an optimal solution, take the initial value of the temperature of each charging sub-interval in the feasible solution as the temperature of each charging sub-interval.

[0182] A first return execution sub-module is configured to, when the feasible solution is not an optimal solution, update the feasible solution according to the direction of the maximum gradient descent, and return to execute the step of judging whether the feasible solution is an optimal solution until the optimal solution is obtained.

[0183] A charging current calculation sub-module is configured to calculate the charging current of the charging sub-interval based on the optimal solution of the temperature of the charging sub-interval and the relationship function of the charging current of the charging sub-interval with respect to the temperature of the charging sub-interval.

[0184] Or,

[0185] a maximum allowable temperature determination sub-module, configured to charge the battery at different charge rates and different states of charge to obtain a maximum allowable temperature;

[0186] a second feasible region determination sub-module, configured to determine a feasible region of the target function with the maximum allowable temperature as a boundary;

[0187] a second initial feasible solution determination sub-module, configured to select a feasible solution in the feasible region to assign an initial value to the charging current of each of the charge subintervals;

[0188] a second judgment sub-module, configured to judge whether the feasible solution is an optimal solution;

[0189] a subinterval current determination sub-module, configured to, when the feasible solution is the optimal solution, take the initial value of the charging current of each of the charge subintervals in the feasible solution as the charging current of each of the charge subintervals;

[0190] a first return execution sub-module, configured to, when the feasible solution is not the optimal solution, update the feasible solution in the direction of the maximum gradient descent, and return to execute the step of judging whether the feasible solution is the optimal solution until the optimal solution is obtained.

[0191] In some embodiments of the present application, the battery charging control device further comprises:

[0192] a relationship curve fitting module, configured to, after calculating the charging current of each of the charge subintervals based on the temperature of the charge subintervals, fit the charging current and the state of charge of each of the charge subintervals to obtain a relationship curve of the charging current with respect to the state of charge under the conditions of the initial state of charge, the target state of charge and the initial temperature;

[0193] a first initial state acquisition module, configured to, when charging starts, acquire the initial state of charge of the battery, the target state of charge set by the user and the initial temperature of the battery;

[0194] a target curve determination module, configured to determine a target relationship curve based on the initial state of charge of the battery, the target state of charge set by the user and the initial temperature of the battery;

[0195] a first state of charge monitoring module, configured to, during the charging process, monitor the real-time state of charge of the battery in real time;

[0196] a charging current determination module, configured to calculate a target charging current from the target relationship curve based on the real-time state of charge;

[0197] a first charging execution module, configured to charge the battery with the target charging current;

[0198] or,

[0199] a relationship straight line fitting module configured to fit the charging current and the state of charge of each of the charge subintervals to obtain a relationship straight line of the charging current with respect to the state of charge under the initial state of charge, the target state of charge and the initial temperature;

[0200] a slope calculation module configured to calculate a slope of the relationship straight line as a charging rate slope;

[0201] an average rate calculation module configured to calculate an average charging rate based on the charging current corresponding to the initial state of charge and the charging current corresponding to the target state of charge on the relationship straight line;

[0202] a writing module configured to write the charging rate slope and the average charging rate into a battery management system of the battery;

[0203] a second initial state acquisition module configured to acquire the initial state of charge of the battery at present, the target state of charge set by the user and the initial temperature of the battery at the beginning of charging;

[0204] a searching module configured to determine a target charging rate slope and a target average charging rate based on the initial state of charge of the battery at present, the target state of charge set by the user and the initial temperature of the battery;

[0205] a second state of charge monitoring module configured to monitor the real-time state of charge of the battery in real time during the charging process;

[0206] a current calculation module configured to calculate a target charging current based on the real-time state of charge, the target charging rate slope and the target average charging rate;

[0207] a second charging execution module configured to charge the battery by using the target charging current.

[0208] In some embodiments of the present application, the target charging current is calculated based on the real-time state of charge, the target charging rate slope and the target average charging rate, and the calculation formula is as follows:

[0209] wherein I(t) is the target charging current, k is the target charging rate slope, SOC is the real-time state of charge, SOC(0) is the initial state of charge, SOC(1) is the target state of charge, midSOC is the midvalue between the initial state of charge and the target state of charge, and C(avg) is the target average charging rate.

[0210] In some embodiments of the present application, the charging control module 305 comprises:

[0211] an internal resistance detection submodule, configured to detect a current internal resistance value of the battery;

[0212] a third judgment submodule, configured to judge whether the current internal resistance value of the battery is greater than a preset internal resistance value;

[0213] a circuit correction submodule, configured to multiply the charging current of the charging subinterval by a correction coefficient a to obtain a corrected current, when the current internal resistance value of the battery is greater than the preset internal resistance value, wherein 0 < a < 1;

[0214] a charging control submodule, configured to charge the battery according to the corrected current of each charging subinterval.

[0215] The battery charging control device can perform the battery charging control method provided by the foregoing embodiments of the present application, and has the corresponding function modules and beneficial effects of performing the battery charging control method.

[0216] FIG. 10 is a structural schematic diagram of an electronic device provided by an embodiment of the present application. The electronic device is intended to represent various forms of digital computers, such as laptops, desktops, workstations, personal digital assistants, servers, blade servers, mainframes, and other appropriate computers. The electronic device can also represent various forms of mobile devices, such as personal digital processors, cellular telephones, smartphones, wearable devices (such as helmets, glasses, watches, etc.), and other similar computing devices. The components shown in the figures, their connections and relationships, and their functions, are merely examples and are not intended to limit the implementations described and / or claimed in this document.

[0217] As shown in FIG. 10, the electronic device includes at least one processor 11, and a memory, such as a read-only memory (ROM) 12, a random access memory (RAM) 13, etc., which is communicatively connected to the at least one processor 11. The memory stores a computer program that can be executed by the at least one processor. The processor 11 can perform various appropriate actions and processes according to the computer program stored in the read-only memory (ROM) 12 or loaded from the storage unit 18 into the random access memory (RAM) 13. In the RAM 13, various programs and data required for the operation of the electronic device can also be stored. The processor 11, the ROM 12, and the RAM 13 are connected to each other through a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0218] A plurality of components in the electronic device are connected to the I / O interface 15, including: an input unit 16, such as a keyboard, a mouse, and the like; an output unit 17, such as various types of displays, speakers, and the like; a storage unit 18, such as a magnetic disk, an optical disk, and the like; and a communication unit 19, such as a network card, a modem, a wireless communication transceiver, and the like. The communication unit 19 allows the electronic device to exchange information / data with other devices through a computer network, such as the Internet, and / or various telecommunication networks.

[0219] The processor 11 can be various general and / or special purpose processing components having processing and computing capabilities. Some examples of the processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various specialized artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any appropriate processor, controller, microcontroller, and the like. The processor 11 performs various methods and processes described above, such as the battery charging control method.

[0220] In some embodiments, the battery charging control method can be implemented as a computer program tangibly embodied in a computer readable storage medium, such as the storage unit 18. In some embodiments, part or all of the computer program can be loaded and / or installed onto the electronic device via the ROM 12 and / or the communication unit 19. When the computer program is loaded onto the RAM 13 and executed by the processor 11, one or more steps of the battery charging control method described above can be performed. Alternatively, in other embodiments, the processor 11 can be configured to perform the battery charging control method by any other appropriate means, such as by means of firmware.

[0221] Various implementations of the systems and techniques described above can be realized in digital electronic circuitry, integrated circuitry, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), a system on a chip (SOC), a complex programmable logic device (CPLD), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include implementation in one or more computer programs that are executable and / or interpretable on a programmable system including at least one programmable processor, which can be special or general purpose, coupled to receive data and instructions from, and to transmit data and instructions to, a storage system, at least one input device, and at least one output device.

[0222] Computer programs used to practice the methods of the application can be written in any combination of one or more programming languages. These computer programs can be implemented on general-purpose computers, special purpose computers, or other programmable data processing apparatus to produce the functions / acts specified in the flow diagrams and / or block diagrams. Computer programs can be applied to a data changed on the functioning of the computer or processing apparatus by transforming the programming language into a machine language.

[0223] In the context of the present application, a computer-readable storage medium can be a tangible medium that can contain or store computer programs for use by or in connection with an instruction execution system, apparatus, or device. Computer-readable storage media can include, but are not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium can be a machine-readable signal medium. More specific examples of a machine-readable storage medium will include one or more lines of electrical connections, portable computer disks, hard disk drives, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or Flash memory), optical fibers, portable compact disc read-only memories (CD-ROMs), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0224] To provide for interaction with a user, the systems and techniques described here can be implemented on an electronic device having a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user and a keyboard and a pointing device (e.g., a mouse or a trackball) by which the user can provide input to the electronic device. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form, including acoustic, speech, or tactile input.

[0225] The systems and techniques described here can be implemented in a computing system that includes a back end component, e.g., as a data server, or that includes a middleware component, e.g., an application server, or that includes a front end component, e.g., a user computer having a graphical user interface or a Web browser through which a user can interact with an implementation of the systems and techniques described here, or any combination of such back end, middleware, or front end components. The components of the system can be interconnected by any form or medium of digital data communication, e.g., a communication network. Examples of communication networks include a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0226] The computing system can include clients and servers. A client and server are generally remote from each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other. A server can be a cloud server, also known as a cloud computing server or cloud host, which is a host product in the cloud computing service system, to solve the defects of large management difficulty and weak business scalability in traditional physical host and VPS service.

[0227] The embodiments of the present application further provide a computer program product, comprising a computer program which, when executed by a processor, implements the battery charging control method provided by any of the embodiments of the present application.

[0228] The computer program code implementing the application can be written in one or more programming languages or combinations of languages including object oriented languages, such as Java, Smalltalk, C++, and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code can execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer can be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection can be made to an external computer (for example, through the Internet using an Internet Service Provider).

[0229] It should be understood that the various forms of flow shown above can be used to reorder, add, or remove steps. For example, the steps described in this application can be performed in parallel, in series, or in a different order, as long as the desired results of the technical solutions of the present application can be achieved, which are not limited herein.

Claims

1. A battery charging control method, comprising: obtaining a current initial state of charge of a battery and a target state of charge set by a user, and determining a charging interval constituted by the initial state of charge and the target state of charge; dividing the charging interval into a plurality of charging sub-intervals; for each of the charging sub-intervals, constructing a function of a charging current of the charging sub-interval and a temperature of the charging sub-interval, and a function of a charging time of the charging sub-interval with respect to the temperature of the charging sub-interval, and determining a target function of a total charging time of the battery from the initial state of charge to the target state of charge with respect to the temperature of each of the charging sub-intervals; for the target function, calculating the charging current of each of the charging sub-intervals with a shortest total charging time as an objective and a maximum allowed charging rate of the battery or a maximum allowed temperature of the battery as a constraint condition; charging the battery according to the charging current of each of the charging sub-intervals.

2. The battery charging control method according to claim 1, wherein for each of the charging sub-intervals, constructing a function of a charging current of the charging sub-interval and a temperature of the charging sub-interval, and a function of a charging time of the charging sub-interval with respect to the temperature of the charging sub-interval, and determining a target function of a total charging time of the battery from the initial state of charge to the target state of charge with respect to the temperature of each of the charging sub-intervals, comprises: letting the charging current of each of the charging sub-intervals be a constant value, and constructing a first expression reflecting a relationship between the charging time of the charging sub-interval and the charging current of the charging sub-interval; constructing a second expression reflecting a relationship between a heat absorption amount of the battery and the charging current of the charging sub-interval, the charging time of the charging sub-interval and the temperature of the charging sub-interval based on a heat balance relationship when the battery generates heat; constructing a third expression reflecting a relationship between the heat absorption amount of the battery and the temperature of the charging sub-interval based on a specific heat formula; simultaneously solving the first expression, the second expression and the third expression to obtain a fourth expression reflecting the function of the charging current of the charging sub-interval and the temperature of the charging sub-interval; simultaneously solving the fourth expression and the first expression to obtain the function of the charging time of the charging sub-interval with respect to the temperature of the charging sub-interval; accumulating the functions of the charging time of all the charging sub-intervals with respect to the temperature of the charging sub-interval to obtain the target function of the total charging time of the battery from the initial state of charge to the target state of charge with respect to the temperature of each of the charging sub-intervals.

3. The battery charging control method according to claim 2, wherein The first expression is: The second expression is: the third expression is: Q(i) = (T(i) - T(i-1)) C p m; where t(i) is a charging time of the i-th charging subinterval, ΔSOC(i) is a state of charge variation amount of the i-th charging subinterval, Cap is a total capacity of the battery, I(i) is a charging current of the i-th charging subinterval, Q(i) is a heat absorption amount of the battery in the i-th charging subinterval, R is an internal resistance of the battery, T(i) is an end temperature of an end position of the i-th charging subinterval, T(i-1) is a start temperature of a start position of the i-th charging subinterval, which is also an end temperature of an end position of an (i-1)-th charging subinterval, P(i) is the heat dissipation power of the battery, C p is the specific heat capacity of the battery, and m is the mass of the battery.

4. The battery charging control method according to claim 3, wherein The battery adopts a liquid cooling mode for heat dissipation, and a heat dissipation power of the battery is: P(i) = R T (T(i)-Tc); wherein R T is the overall heat transfer resistance between the battery and the coolant, and Tc is the temperature of the coolant.

5. The battery charging control method according to claim 3, wherein The fourth expression is:

6. The battery charging control method according to claim 3, wherein The relationship function of the charging time of the charging subinterval with respect to the temperature of the charging subinterval is: The total charging time of the battery from the initial state of charge to the target state of charge is a target function with respect to the temperature of each of the charging subintervals: t(tot) is the total charging time of the battery from the initial state of charge to the target state of charge, and n is a total number of the charging sub-intervals.

7. The battery charging control method according to any one of claims 1-6, wherein, for the target function, calculating the charging current of each of the charging sub-intervals with a shortest total charging time as an objective and a maximum allowed charging rate of the battery or a maximum allowed temperature of the battery as a constraint condition, comprises: preliminarily charging the battery at different states of charge at different temperatures to obtain the maximum allowed charging rate; determining a feasible region of the objective function with the maximum allowed charging rate as a boundary; selecting a feasible solution within the feasible region, and assigning initial values of temperatures of the charging sub-intervals to the feasible solution; determining whether the feasible solution is an optimal solution; if yes, assigning the initial values of the temperatures of the charging sub-intervals in the feasible solution as the temperatures of the charging sub-intervals; if no, updating the feasible solution according to a direction of maximum gradient descent, and returning to the step of determining whether the feasible solution is an optimal solution until an optimal solution is obtained; calculating charging currents of the charging sub-intervals based on the optimal solution of the temperatures of the charging sub-intervals and a function of the charging currents of the charging sub-intervals and the temperatures of the charging sub-intervals; or, previously charging the battery with different states of charge at different charging rates to obtain a maximum allowed temperature; determining a feasible region of the objective function with the maximum allowed temperature as a boundary; selecting a feasible solution within the feasible region, and assigning initial values of charging currents of the charging sub-intervals to the feasible solution; determining whether the feasible solution is an optimal solution; if yes, assigning the initial values of the charging currents of the charging sub-intervals in the feasible solution as the charging currents of the charging sub-intervals; if no, updating the feasible solution according to a direction of maximum gradient descent, and returning to the step of determining whether the feasible solution is an optimal solution until an optimal solution is obtained.

8. The battery charging control method according to any one of claims 1-6, after the step of calculating the charging currents of the charging sub-intervals based on the temperatures of the charging sub-intervals, the method further comprises: fitting the charging currents and the states of charge of the charging sub-intervals to obtain a relationship curve of the charging currents with respect to the states of charge under initial states of charge, target states of charge and initial temperatures; at the beginning of charging, obtaining a current initial state of charge of the battery, a target state of charge set by a user and an initial temperature of the battery; determining a target relationship curve based on the current initial state of charge of the battery, the target state of charge set by the user and the initial temperature of the battery; during charging, monitoring a real-time state of charge of the battery in real time; calculating a target charging current from the target relationship curve based on the real-time state of charge; charging the battery with the target charging current; or, fitting the charging currents and the states of charge of the charging sub-intervals to obtain a relationship straight line of the charging currents with respect to the states of charge under initial states of charge, target states of charge and initial temperatures; calculating a slope of the relationship straight line as a charging rate slope; calculating an average charging rate based on a charging current corresponding to the initial state of charge and a charging current corresponding to the target state of charge on the relationship straight line; writing the charging rate slope and the average charging rate into a battery management system of the battery; at the beginning of charging, obtaining a current initial state of charge of the battery, a target state of charge set by a user and an initial temperature of the battery; determining a target charging rate slope and a target average charging rate based on an initial state of charge of the battery, a target state of charge set by a user, and an initial temperature of the battery; monitoring a real-time state of charge of the battery in real time during the charging process; calculating a target charging current based on the real-time state of charge, the target charging rate slope, and the target average charging rate; charging the battery with the target charging current.

9. The battery charging control method according to claim 8, wherein A target charging current is calculated based on the real-time state of charge, the target charging rate slope, and the target average charging rate, and the calculation formula is as follows: wherein I(t) is the target charging current, k is the target charging rate slope, SOC is the real-time state of charge, SOC(0) is the initial state of charge, SOC(1) is the target state of charge, midSOC is a mid-value between the initial state of charge and the target state of charge, and C(avg) is the target average charging rate.

10. The battery charging control method according to any one of claims 1-6, 9, wherein, charging the battery with the charging current of each charging interval, comprising: detecting a current internal resistance value of the battery; determining whether the current internal resistance value of the battery is greater than a preset internal resistance value; multiplying the charging current of each charging interval by a correction factor a to obtain a corrected current, wherein 0 < a < 1, when the current internal resistance value of the battery is greater than the preset internal resistance value; charging the battery with the corrected current of each charging interval.

11. An electronic device, comprising: 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 battery charging control method according to any one of claims 1-10.

12. A computer readable storage medium having stored thereon a computer program, which program, when executed by a processor, implements the battery charging control method according to any one of claims 1-10.

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