Charging method and device, battery pack, electronic equipment and computer readable storage medium

Abstract

The invention discloses a charging method and device, a battery pack, electronic equipment and a storage medium, the method is applied to charging a secondary battery, and the method comprises the following steps: charging the secondary battery; in the process of charging the secondary battery, maintaining the battery temperature of the secondary battery to be greater than or equal to a preset battery temperature; wherein the positive electrode active material of the secondary battery comprises LiMPO4, and M comprises Mn and Fe elements. According to the secondary battery designed by the scheme, the secondary battery is charged under the condition that the battery temperature is greater than or equal to the preset battery temperature, so that after the charging temperature of the secondary battery is increased, the lithium removal depth of a positive electrode active material lithium manganese iron phosphate in the secondary battery can be correspondingly improved, and the capacity of the secondary battery is further improved; meanwhile, the diffusion speed and the lithium removal speed of lithium ions are improved in an environment higher than the preset battery temperature, so that the charging time of the secondary battery is shortened, the charging speed of the secondary battery is improved, and the requirement of quick charging can be met.

Description

Charging method, device, battery pack, electronic device and computer-readable storage medium Technical Field

[0001] The present application relates to the field of battery charging technology, and in particular to a charging method, device, battery pack, electronic device and computer-readable storage medium. Background Art

[0002] Lithium-ion secondary batteries have the characteristics of high capacity, high energy density, good charge and discharge cycle characteristics, and can maintain rated output for a long time. They have been widely used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, as well as power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace and other fields.

[0003] At present, lithium batteries using lithium iron manganese phosphate as the positive electrode active material are widely used due to their large capacity. However, the charging rate of lithium iron manganese phosphate batteries is low and cannot meet users' needs for fast charging.

[0004] Summary of the Invention

[0005] In view of the above problems, the present application provides a charging method, device, battery pack, electronic device and computer-readable storage medium, which can solve the problem of low charging rate of current lithium manganese iron phosphate batteries.

[0006] In a first aspect, the present application provides a charging method, the method comprising: charging a secondary battery; during the charging process of the secondary battery, maintaining the battery temperature of the secondary battery greater than or equal to a preset battery temperature; wherein the positive electrode active material of the secondary battery comprises LiMPO4, wherein M comprises Mn and Fe elements.

[0007] In the technical solution of the embodiment of the present application, since the preset battery temperature of this solution can be designed to be greater than the temperature of the normal temperature environment, the battery temperature of the secondary battery needs to be maintained greater than or equal to the preset battery temperature during the charging process of the secondary battery in this solution. Therefore, the adoption of this solution allows the secondary battery to be charged in a higher battery temperature environment (for example, a temperature higher than the preset battery temperature). When the charging temperature of the secondary battery is increased, the delithiation depth of the positive electrode active material LiMPO4 in the secondary battery can be correspondingly increased, thereby increasing the capacity of the secondary battery; at the same time, in an environment higher than the preset battery temperature, the diffusion rate and delithiation rate of lithium ions are increased, thereby reducing the charging time of the secondary battery, increasing the charging rate of the secondary battery, and meeting the demand for fast charging.

[0008] In some embodiments, the positive electrode material includes at least one of the following materials: LiMn 1-y Fe yPO4, y is any value in the range of 0.001 to 0.5; Li 1+t Mn 1-c Fe c P 1-z RzO4, t is any value in the range of -0.100 to 0.100, c is any value in the range of 0.001 to 0.500, z is any value in the range of 0.001 to 0.100, and R includes one or more elements selected from B (boron), S, Si and N; Li 1+w C m Mn 1-u Fe u P 1-a R a O 4-n D n , wherein the C includes one or more elements selected from Zn, Al, Na, K, Mg, Nb, Mo and W, the R includes one or more elements selected from B (boron), S, Si and N, the D includes one or more elements selected from S, F, Cl and Br, w is any value in the range of -0.100 to 0.100, u is any value in the range of 0.001 to 0.500, a is any value in the range of 0.001 to 0.100, n is any value in the range of 0.001 to 0.1, and m is any value in the range of 0.9 to 1.1.

[0009] In some embodiments, maintaining the battery temperature of the secondary battery greater than or equal to a preset battery temperature during charging of the secondary battery includes maintaining the battery temperature of the secondary battery greater than or equal to the preset battery temperature throughout the entire charging process. This embodiment maintains the battery temperature of the secondary battery greater than or equal to the preset battery temperature throughout the entire charging process, thereby maintaining a higher battery temperature throughout the entire charging process, thereby further improving the capacity and charging rate of the secondary battery.

[0010] In some embodiments, maintaining the battery temperature of the secondary battery greater than or equal to a preset battery temperature during charging of the secondary battery includes: maintaining the battery temperature of the secondary battery greater than or equal to the preset battery temperature during a portion of charging of the secondary battery.

[0011] In some embodiments, during a portion of the charging process of the secondary battery, maintaining the battery temperature of the secondary battery greater than or equal to a preset battery temperature includes: after the SOC of the secondary battery reaches a preset value, maintaining the battery temperature of the secondary battery greater than or equal to the preset battery temperature.

[0012] In some embodiments, maintaining the battery temperature of the secondary battery greater than or equal to a preset battery temperature during a portion of the secondary battery charging process includes: maintaining the battery temperature of the secondary battery greater than or equal to the preset battery temperature after the secondary battery charging time reaches a preset time. In embodiments of the present application, maintaining the battery temperature of the secondary battery greater than or equal to the preset battery temperature during a portion of the secondary battery charging process allows the secondary battery to be at a higher battery temperature during the portion of the charging process, thereby saving power consumption while increasing the capacity and charging rate of the secondary battery.

[0013] In some embodiments, maintaining the battery temperature of the secondary battery greater than or equal to a preset battery temperature includes: obtaining the battery temperature of the secondary battery; if it is determined that the battery temperature of the secondary battery is less than the preset battery temperature, heating the secondary battery to make the battery temperature of the secondary battery greater than or equal to the preset battery temperature.

[0014] Optionally, maintaining the battery temperature of the secondary battery greater than or equal to a preset battery temperature includes: obtaining the battery temperature of the secondary battery and the SOC of the secondary battery; if it is determined that the battery temperature of the secondary battery is less than the preset battery temperature and / or the SOC of the secondary battery is less than a preset threshold, heating the secondary battery so that the battery temperature of the secondary battery is greater than or equal to the preset battery temperature.

[0015] In some embodiments, heating the secondary battery includes: calculating the temperature difference between the battery temperature of the secondary battery and a preset battery temperature; obtaining a temperature adjustment method based on the temperature difference; and heating the secondary battery according to the temperature adjustment method to maintain the battery temperature of the secondary battery greater than or equal to the preset battery temperature.

[0016] In some embodiments, the secondary battery includes a battery casing, a battery body, and a hydrothermal pipe; the hydrothermal pipe is arranged around the battery body and is located inside the battery casing, and the hydrothermal pipe is connected to the control valve; the temperature regulation method is obtained according to the temperature difference, including: adjusting the opening of the control valve according to the temperature difference to control the temperature regulation method. The embodiment of the present application first calculates the temperature difference between the battery temperature of the secondary battery and the preset battery temperature or jointly calculates the temperature difference between the battery temperature of the secondary battery and the preset battery temperature and determines the relationship between the SOC of the secondary battery and the preset value. Afterwards, it is determined whether the secondary battery needs to be heated based on the temperature difference and the relationship between the SOC of the secondary battery and the preset value. If necessary, in one embodiment, the secondary battery is heated / heated using a hydrothermal pipe surrounding the battery body of the secondary battery. During the temperature rise / heating process, the temperature regulation method is controlled by adjusting the opening of the control valve, and the battery temperature of the secondary battery is adjusted according to the temperature regulation method, so that the temperature of the secondary battery continues to rise and is greater than or equal to the preset voltage temperature. Therefore, this solution controls the opening of the control valve through the temperature difference, thereby achieving controllable temperature adjustment of the secondary battery, avoiding the impact of too fast temperature regulation on the life of the secondary battery, and avoiding the problem of low charging rate caused by too slow temperature regulation.

[0017] In some embodiments, charging a secondary battery includes: obtaining a SOC value of the secondary battery; and determining a charging method for the secondary battery based on the SOC value of the secondary battery and a preset value. This embodiment determines different charging methods based on different relationships between the SOC value of the secondary battery and the preset value, thereby selecting a charging method that adapts to different SOC values, thereby improving the capacity and charging rate of the secondary battery.

[0018] In some embodiments, the charging method of the secondary battery is determined based on the SOC value and a preset value of the secondary battery, including: determining whether the SOC value of the secondary battery is greater than or equal to the preset value; if it is determined that the SOC value of the secondary battery is greater than or equal to the preset value, using a first constant current charging current to perform constant current charging on the secondary battery; and when the real-time voltage of the constant current charging is greater than or equal to the first constant voltage charging voltage, using the first constant voltage charging voltage to perform constant voltage charging on the secondary battery until the current of the secondary battery is greater than or equal to the preset cut-off current. In the embodiment of the present application, when the SOC value of the secondary battery is greater than or equal to the preset value, the secondary battery is constant current charged, and when the real-time voltage of the secondary battery is greater than or equal to the first constant voltage charging voltage during the constant current charging process, the secondary battery using the first constant voltage charging voltage is constant voltage charged, thereby eliminating the influence of polarization of the battery cell during constant current charging on the capacity of the secondary battery through the constant current first and constant voltage later charging method, thereby increasing the capacity of the secondary battery.

[0019] In some embodiments, a charging method for the secondary battery is determined based on the SOC value of the secondary battery and a preset value, including: determining whether the SOC value of the secondary battery is less than the preset value; if the SOC value of the secondary battery is determined to be less than the preset value, performing preliminary charging on the secondary battery, and after the SOC value of the secondary battery is greater than or equal to the SOC threshold during the preliminary charging process, using a second constant current charging current to perform constant current charging on the secondary battery, and when the real-time voltage of the constant current charging is greater than or equal to the second constant voltage charging voltage, using the second constant voltage charging voltage to perform constant voltage charging on the secondary battery until the current of the secondary battery is greater than or equal to the preset cut-off current. In this embodiment, preliminary charging is performed when the SOC value is less than the preset value, and after the SOC value is greater than or equal to the value, charging is performed using a constant current followed by a constant voltage method, thereby using different charging methods adapted to different stages of charging, thereby increasing the capacity of the secondary battery while increasing the charging rate of the secondary battery.

[0020] In some embodiments, performing preliminary charging on the secondary battery includes: performing constant current charging on the secondary battery using a third constant current charging current; or performing constant voltage charging on the secondary battery using a third constant voltage charging voltage. The embodiments of the present application perform preliminary charging on the secondary battery using a constant current or constant voltage method, thereby achieving rapid charging of the secondary battery.

[0021] In some embodiments, the preset value is determined according to the molar ratio f of the iron element in the iron and manganese elements in the positive electrode active material.

[0022] In some embodiments, the preset value includes fS, where S is the SOC value of the secondary battery when it is fully charged.

[0023] In some embodiments, the preset battery temperature includes any temperature in a preset temperature range, wherein the preset temperature range is any one of 30°C to 90°C, 30°C to 80°C, and 40°C to 50°C. In the embodiment of the present application, the preset battery temperature is designed to be any temperature in the preset temperature range, and the preset temperature range is any one of 30°C to 90°C, 30°C to 80°C, and 40°C to 50°C, so that the life of the secondary battery and the operation of the entire vehicle are not affected by high temperature, and the secondary battery can be quickly charged and its capacity can be effectively utilized.

[0024] In a second aspect, the present application provides a charging device, which includes a charging module and a maintenance module; the charging module is used to charge a secondary battery; the maintenance module is used to maintain the battery temperature of the secondary battery greater than or equal to a preset battery temperature during the charging process of the secondary battery; wherein, the positive electrode active material of the secondary battery includes LiMPO4, wherein M includes Mn and Fe elements.

[0025] In the technical solution of the embodiment of the present application, during the charging process of the secondary battery, the solution maintains the battery temperature of the secondary battery greater than or equal to the preset battery temperature. Since the preset battery temperature of the solution can be designed to be greater than the temperature of the normal temperature environment, the solution can enable the secondary battery to be charged in a higher battery temperature environment. After the charging temperature of the secondary battery is increased, the delithiation depth of the positive electrode active material LiMPO4 in the secondary battery can be correspondingly increased, thereby increasing the capacity of the secondary battery; at the same time, in an environment higher than the preset battery temperature, the diffusion rate and delithiation rate of lithium ions are increased, thereby reducing the charging time of the secondary battery, increasing the charging rate of the secondary battery, and meeting the needs of fast charging.

[0026] In some embodiments, the maintaining module is specifically configured to maintain the battery temperature of the secondary battery greater than or equal to a preset battery temperature during the entire process of charging the secondary battery.

[0027] In some embodiments, the maintaining module is further specifically configured to maintain the battery temperature of the secondary battery greater than or equal to a preset battery temperature during a portion of the charging process of the secondary battery.

[0028] In some embodiments, the maintaining module is further specifically configured to maintain the battery temperature of the secondary battery greater than or equal to a preset battery temperature after the SOC of the secondary battery reaches a preset value.

[0029] In some embodiments, the maintaining module is further specifically configured to maintain the battery temperature of the secondary battery greater than or equal to a preset battery temperature after the charging time of the secondary battery reaches a preset time.

[0030] In some embodiments, the maintenance module is further specifically used to obtain the battery temperature of the secondary battery; if it is determined that the battery temperature of the secondary battery is lower than the preset battery temperature, the secondary battery is heated to make the battery temperature of the secondary battery higher than or equal to the preset battery temperature.

[0031] In some embodiments, the maintenance module is further specifically used to obtain the battery temperature of the secondary battery and / or the SOC value of the secondary battery; if it is determined that the battery temperature of the secondary battery is lower than the preset battery temperature and / or the SOC value of the secondary battery is lower than the preset value, the secondary battery is heated to make the battery temperature of the secondary battery greater than or equal to the preset battery temperature.

[0032] In some embodiments, the maintenance module is further specifically used to calculate the temperature difference between the battery temperature of the secondary battery and the preset battery temperature; obtain a temperature adjustment method based on the temperature difference; and heat the secondary battery according to the temperature adjustment method to maintain the battery temperature of the secondary battery greater than or equal to the preset battery temperature.

[0033] In some embodiments, the secondary battery includes a water heating pipe; the water heating pipe is connected to the control valve; the maintenance module is further specifically used to adjust the opening of the control valve according to the temperature difference to control the temperature regulation method.

[0034] In some embodiments, the charging module is further specifically configured to obtain an SOC value of the secondary battery; and determine a charging method for the secondary battery according to the SOC value of the secondary battery and a preset value.

[0035] In some embodiments, the charging module is further specifically used to determine whether the SOC value of the secondary battery is greater than or equal to a preset value; if it is determined that the SOC value of the secondary battery is greater than or equal to the preset value, the secondary battery is constant-current charged with a first constant-current charging current; and when the real-time voltage of the constant-current charging is greater than or equal to the first constant-voltage charging voltage, the secondary battery is constant-voltage charged with the first constant-voltage charging voltage until the current of the secondary battery is greater than or equal to the preset cut-off current.

[0036] In some embodiments, the charging module is further specifically used to determine whether the SOC value of the secondary battery is less than a preset value; if it is determined that the SOC value of the secondary battery is less than the preset value, the secondary battery is preliminarily charged, and after the SOC value of the secondary battery is greater than or equal to the value, the secondary battery is constant-current charged with a second constant-current charging current, and when the real-time voltage of the constant-current charging is greater than or equal to the second constant-voltage charging voltage, the secondary battery is constant-voltage charged with a second constant-voltage charging voltage until the current of the secondary battery is greater than or equal to the preset cut-off current.

[0037] In some embodiments, the charging module is further specifically configured to perform constant-current charging on the secondary battery using a third constant-current charging current; or perform constant-voltage charging on the secondary battery using a third constant-voltage charging voltage.

[0038] In a third aspect, the present application provides a battery pack comprising: a secondary battery, wherein the positive electrode active material of the secondary battery comprises LiMPO4, wherein M comprises Mn and Fe elements; and a temperature regulating mechanism for maintaining the battery temperature of the secondary battery greater than or equal to a preset battery temperature.

[0039] In a fourth aspect, the present application provides an electronic device comprising a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the method in the first aspect and any optional implementation of the first aspect is executed.

[0040] In a fifth aspect, the present application provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the method in the first aspect or any optional implementation of the first aspect is executed.

[0041] In a sixth aspect, the present application provides a computer program product, which, when running on a computer, enables the computer to execute the method in the first aspect or any optional implementation of the first aspect.

[0042] The above description is only an overview of the technical solution of the embodiment of the utility model. In order to more clearly understand the technical means of the embodiment of the utility model, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the embodiment of the utility model more obvious and easy to understand, the specific implementation method of the utility model is specifically listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0044] FIG1 is a schematic structural diagram of a vehicle provided in this application;

[0045] FIG2 is a schematic diagram of a first flow chart of the charging method provided in this application;

[0046] FIG3 is a first structural schematic diagram of a battery pack provided in this application;

[0047] FIG4 is a second structural schematic diagram of the battery pack provided in this application;

[0048] FIG5 is a table showing the relationship between temperature and charge and discharge capacity provided in this application;

[0049] FIG6 is a discounted schematic diagram of the relationship between temperature and charge and discharge capacity provided by this application;

[0050] FIG7 is a schematic structural diagram of the charging device provided in this application;

[0051] FIG8 is a schematic structural diagram of the electronic device provided in this application.

[0052] The accompanying drawings in the specific implementation manner are as follows:

[0053] 10-Vehicle; 100-Battery; 200-Controller; 300-Motor; A1-Battery housing; A2-Secondary battery; A3-Temperature acquisition device; A4-Water heating pipe; A5-Control valve; 700-Charging module; 710-Maintenance module; 8-Electronic device; 801-Processor; 802-Memory; 803-Communication bus. DETAILED DESCRIPTION

[0054] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0055] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0056] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0057] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0058] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0059] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0060] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0061] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0062] Lithium-ion secondary batteries have the characteristics of high capacity, high energy density, good charge and discharge cycle characteristics, and can maintain rated output for a long time. They have been widely used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, as well as power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace and other fields.

[0063] The inventors of this application have noticed that since lithium manganese iron phosphate batteries have a higher voltage platform than lithium iron phosphate batteries, their energy density can be about 15% higher than that of lithium iron phosphate batteries and they have the safety and low cost of lithium iron phosphate batteries, lithium manganese iron phosphate batteries are widely used in the current market.

[0064] Although lithium manganese iron phosphate batteries have the advantage of high energy density, the delithiation rate of the positive active material on the positive electrode plate of the lithium manganese iron phosphate battery is slow and the charging rate is low, which brings inconvenience to users; in addition, the delithiation depth of the positive active material lithium manganese iron phosphate in the lithium manganese iron phosphate battery is low, which makes it impossible to fully utilize the capacity of the lithium manganese iron phosphate battery.

[0065] The inventors of the present application have discovered that by charging the lithium iron phosphate battery at high temperature, the polarization effect of the material itself can be eliminated, and the delithiation depth of the positive electrode active material lithium iron phosphate in the lithium iron phosphate battery can be increased, thereby increasing the capacity of the lithium iron phosphate battery; at the same time, high temperature helps to accelerate the diffusion rate and delithiation rate of lithium ions, which is beneficial to reduce the charging time of the lithium iron phosphate battery, can meet the needs of fast charging, and thus solve the problem of slow charging speed and inability to fully utilize the capacity of the lithium iron phosphate battery.

[0066] After in-depth research, the inventors of this application have designed a charging method, device, battery pack, electronic device, and computer-readable storage medium for a secondary battery using lithium manganese iron phosphate as the positive active material of the positive electrode plate. First, a preset battery temperature is configured. Generally, the preset battery temperature is designed to be greater than the temperature under normal temperature. During the charging process of the secondary battery, the battery temperature of the secondary battery is maintained greater than or equal to the preset battery temperature, so that the secondary battery is charged at a higher battery temperature. When the charging temperature of the secondary battery is increased, the delithiation depth of the positive active material LiMPO4 in the secondary battery can be correspondingly increased, thereby increasing the capacity of the secondary battery. At the same time, in an environment above the preset battery temperature, the diffusion rate and delithiation rate of lithium ions are increased, thereby reducing the charging time of the secondary battery and increasing the charging rate of the secondary battery, which can meet the demand for fast charging.

[0067] The charging method, device, electronic device, and computer-readable storage medium disclosed in the embodiments of the present application can be applied to power equipment that uses a battery as a power source, including but not limited to power-consuming devices such as vehicles, ships, or aircraft.

[0068] For the convenience of description, the following embodiments are described by taking a vehicle 10 as an example of an electrical device according to an embodiment of the present application.

[0069] Please refer to Figure 1, which is a schematic structural diagram of a vehicle 10 provided in some embodiments of the present application. The vehicle 10 can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is provided inside the vehicle 10, and the battery 100 can be provided at the bottom, head or tail of the vehicle 10. The battery 100 can be used to power the vehicle 10. For example, the battery 100 can serve as an operating power source for the vehicle 10. The vehicle 10 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to power the motor 300, for example, for starting, navigating and operating power requirements of the vehicle 10 during driving.

[0070] In some embodiments of the present application, the battery 100 can serve not only as an operating power source for the vehicle 10 , but also as a driving power source for the vehicle 10 , replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 10 .

[0071] It should be noted that in the present application, the battery 100 serves as a driving power source for the vehicle 10 , thereby serving as driving power provided by the vehicle 10 .

[0072] According to some embodiments of the present application, a charging method according to an embodiment of the present application can control the charging of a secondary battery, wherein the secondary battery is a battery in which the positive electrode active material in the positive electrode sheet is LiMPO4. The charging method can be executed by a computing device, which includes but is not limited to a controller, a chip, and a battery management system (BMS). As shown in FIG2 , the charging method can be implemented in the following manner, including:

[0073] Step S200: charging the secondary battery.

[0074] Step S210 : During the process of charging the secondary battery, maintaining the battery temperature of the secondary battery greater than or equal to a preset battery temperature.

[0075] In the above embodiment, the positive electrode active material LiMPO4, wherein M includes Mn and Fe elements, means that: the M element may be Mn and Fe, or the M element may optionally include non-metallic elements in addition to Mn and Fe, such as one or more elements of B, S, Si, and N; or the M element may include alkali metal elements (such as one or two elements of Na and K), alkaline earth metal elements (such as Mg), transition metal elements (such as one or more elements of Zn, Al, Nb, Mo, and W), halogen elements (such as one or more elements of F, Cl, and Br), etc. It can be understood that the M element may be a doping element of the Mn element or the Fe element, the M element may also be a doping element of the Li element, or the M element may also be a doping element of the P element or the O element.

[0076] In the above-described embodiment, a computing device (e.g., a battery management system (BMS)) can obtain the current state of the secondary battery, such as the charging state, the operating state, and the idle state. The charging state refers to the state in which the secondary battery is connected to an external power supply device and the external power supply device is charging the secondary battery. The operating state, also known as the discharging state, is the state in which the secondary battery releases its stored energy as an external power source. The idle state refers to the state in which the secondary battery is neither charging nor discharging. Specifically, the computing device can identify whether the external power supply device has a charging current, or whether the secondary battery currently has a charging current / charging voltage, thereby determining whether the secondary battery is in a charging state.

[0077] On the basis of the above, the secondary battery is connected to the external power supply device and the electric energy of the external power supply device is charged into the secondary battery, that is, the computing device charges the secondary battery. In addition to controlling the charging of the secondary battery, the computing device of this solution also needs to maintain the battery temperature of the secondary battery greater than or equal to the preset battery temperature during the charging process of the secondary battery. It should be noted here that the maintenance described in this embodiment includes the following meanings: First, when the battery temperature of the secondary battery is not greater than or equal to the preset battery temperature, the battery temperature of the secondary battery is adjusted to greater than or equal to the preset battery temperature through temperature adjustment means. Second, during the charging process of the secondary battery, there will be a certain loss in battery temperature, and temperature adjustment means are required to ensure / maintain the battery temperature of the secondary battery greater than or equal to the preset battery temperature.

[0078] Among them, the preset battery temperature can be set to be relatively higher than the normal ambient temperature. In one embodiment, the normal ambient temperature described in this scheme is an ambient temperature of 20°C to 25°C, so that the secondary battery always maintains a higher battery temperature during the charging process, and the higher battery temperature can correspondingly increase the delithiation depth of the positive electrode active material LiMPO4 in the secondary battery, thereby increasing the capacity of the secondary battery; at the same time, in an environment higher than the preset battery temperature, the diffusion rate and delithiation rate of lithium ions are increased, thereby reducing the charging time of the secondary battery, increasing the charging rate of the secondary battery, and meeting the needs of fast charging.

[0079] The charging method designed above maintains the battery temperature of the secondary battery greater than or equal to the preset battery temperature during the charging process of the secondary battery. Since the preset battery temperature of the present scheme can be designed to be greater than the temperature of the normal temperature environment, the present scheme can enable the secondary battery to be charged in a higher battery temperature environment. When the charging temperature of the secondary battery is increased, the delithiation depth of the positive electrode active material LiMPO4 in the secondary battery can be correspondingly increased, thereby increasing the capacity of the secondary battery. At the same time, in an environment higher than the preset battery temperature, the diffusion rate and delithiation rate of lithium ions are increased, thereby reducing the charging time of the secondary battery, increasing the charging rate of the secondary battery, and meeting the needs of fast charging.

[0080] As a possible implementation, the computing device may maintain the battery temperature of the secondary battery greater than or equal to a preset battery temperature throughout the entire process of charging the secondary battery. The entire process of charging the secondary battery refers to the entire period from the start of charging to the end of charging the secondary battery. This ensures that the secondary battery maintains a temperature greater than the preset battery temperature throughout the entire charging process, further improving the charging rate and capacity of the secondary battery.

[0081] As another possible implementation, the computing device maintains the battery temperature of the secondary battery greater than or equal to a preset battery temperature during a portion of the process of charging the secondary battery. The portion of the process of charging the secondary battery refers to a period of time from the start of charging the secondary battery to the end of charging the secondary battery. For example, as a specific example, the computing device may maintain the battery temperature of the secondary battery greater than or equal to a preset battery temperature after the charging time of the secondary battery reaches a preset time. For example, the preset time is 10 minutes. On this basis, the computing device may first charge the secondary battery for 10 minutes. During the 10 minutes of charging the secondary battery, regardless of the temperature of the secondary battery, after the charging time of the secondary battery reaches 10 minutes, the computing device maintains the battery temperature of the secondary battery to be greater than or equal to the preset battery temperature and charges the secondary battery.

[0082] As another specific example, the computing device may further maintain the battery temperature of the secondary battery greater than or equal to a preset battery temperature after the SOC of the secondary battery reaches a preset value.

[0083] The battery SOC represents the state of charge (SOC) of the battery, which is used to reflect the remaining capacity of the battery. Its value is defined as the ratio of the remaining capacity of the battery to the battery capacity.

[0084] As previously described, a computing device (e.g., a battery management system (BMS)) can obtain the current state of a secondary battery. In addition to obtaining the current state of the secondary battery, the computing device can also obtain the state of charge (SOC) value of the secondary battery. As a possible implementation, this solution can pre-calibrate each SOC value of the secondary battery with the corresponding open-circuit voltage of the secondary battery. The computing device can continuously or intermittently obtain the open-circuit voltage of the secondary battery during the charging process, thereby determining the corresponding SOC value based on the obtained open-circuit voltage.

[0085] For example, the preset value is 0.4, and the computing device maintains the battery temperature of the secondary battery greater than or equal to the preset battery temperature after the SOC of the secondary battery reaches 0.4 during the charging process.

[0086] This solution can maintain the battery temperature of the secondary battery greater than or equal to the preset battery temperature throughout the entire process of secondary battery charging, so that the secondary battery is at a higher battery temperature throughout the entire charging process, thereby further improving the capacity and charging rate of the secondary battery; it can also maintain the battery temperature of the secondary battery greater than or equal to the preset battery temperature during part of the secondary battery charging process, so that the secondary battery is at a higher battery temperature during part of the charging process, thereby saving power consumption on the basis of improving the capacity and charging rate of the secondary battery.

[0087] As described above, the computing device can maintain the battery temperature of the secondary battery greater than or equal to the preset battery temperature at various charging opportunities.

[0088] If the battery temperature of the secondary battery needs to be maintained, the specific value of the battery temperature of the secondary battery needs to be known first, that is, the computing device needs to obtain the battery temperature of the secondary battery first. The computing device can obtain the battery temperature of the secondary battery in a variety of ways. For example, as a possible embodiment, as shown in FIG3 , the battery pack includes a battery housing A1, a secondary battery A2, and a temperature acquisition device A3. The temperature acquisition device A3 can be specifically arranged on the surface of the secondary battery A2 and located within the battery housing A1 as shown in FIG3 . The computing device is electrically connected to the temperature acquisition device A3. The computing device identifies the battery temperature of the secondary battery by acquiring the collected data transmitted by the temperature acquisition device A3. Of course, in addition to being arranged on the surface of the secondary battery A2, in order to avoid affecting the operation of the secondary battery, the temperature acquisition device A3 can also be arranged on the outer surface of the battery housing A1 or in the surrounding environment.

[0089] On the basis of the above, the computing device can compare the battery temperature of the secondary battery with the preset battery temperature to determine whether the battery temperature of the secondary battery is greater than or equal to the preset battery temperature. If it is determined that the battery temperature of the secondary battery is greater than or equal to the preset battery temperature, it means that the secondary battery is currently in a battery temperature environment higher than the preset battery temperature. In this case, the computing device only needs to maintain the battery temperature of the secondary battery so that it is greater than or equal to the preset battery temperature.

[0090] For example, as a possible example, assuming that the preset battery temperature is 40°C, the computing device obtains the battery temperature of the secondary battery as 45°C, that is, the battery temperature of the secondary battery of 45°C is greater than the preset battery temperature of 40°C. On this basis, the computing device only needs to maintain the battery temperature of the secondary battery so that it is always greater than the preset battery temperature of 40°C.

[0091] As a possible implementation method, when the ambient temperature of the secondary battery is low or at room temperature, the battery temperature of the secondary battery is generally low. In this case, the battery temperature may be lower than the preset battery temperature, that is, the computing device determines that the battery temperature of the secondary battery is lower than the preset battery temperature. In this case, the computing device heats the secondary battery so that the battery temperature of the secondary battery is greater than or equal to the preset battery temperature.

[0092] For example, as a possible example, assuming that the preset battery temperature is 40°C, the computing device obtains the battery temperature of the secondary battery as 25°C, that is, the battery temperature of the secondary battery of 25°C is lower than the preset battery temperature of 40°C. On this basis, the computing device heats the secondary battery so that the battery temperature of the secondary battery is greater than or equal to 40°C, and maintains the battery temperature of the secondary battery greater than or equal to 40°C.

[0093] As a further embodiment, since a certain amount of heat energy is generated during battery charging, when the temperature difference between the external environment and the battery is not large, that is, the battery temperature does not dissipate quickly, this solution can stop heating the secondary battery when the adjusted battery temperature is equal to the preset battery temperature.

[0094] For example, according to the above example, when the preset battery temperature is 40° C. and the battery temperature of the secondary battery is 25° C., this solution only needs to adjust the battery temperature of the secondary battery to 40° C.

[0095] Optionally, in the process of determining whether the secondary battery needs to be heated, the battery temperature of the secondary battery and the SOC of the secondary battery may be considered simultaneously, that is, the battery temperature of the secondary battery and the SOC of the secondary battery are obtained; if it is determined that the battery temperature of the secondary battery is lower than a preset battery temperature and / or the SOC of the secondary battery is lower than a preset threshold value, the secondary battery is heated so that the battery temperature of the secondary battery is higher than or equal to the preset battery temperature.

[0096] The embodiments of the present application determine the relationship between the battery temperature of the secondary battery and a preset battery temperature or jointly calculate the temperature difference between the battery temperature of the secondary battery and the preset battery temperature and determine the relationship between the SOC of the secondary battery and a preset value. When the battery temperature is lower than the preset battery temperature or the battery temperature is lower than the preset battery temperature and / or the SOC of the secondary battery is lower than the preset value, the secondary battery is heated to increase the battery temperature so that the battery temperature of the secondary battery is higher than or equal to the preset battery temperature, thereby ensuring that the secondary battery is charged in an environment higher than the preset battery temperature, thereby improving the capacity and charging rate of the secondary battery.

[0097] According to some embodiments of the present application, it is described above that when the battery temperature of the secondary battery is lower than a preset battery temperature, the computing device may heat the secondary battery to increase the temperature.

[0098] As a possible implementation, this solution may use a high-rate charging method to increase the temperature of the secondary battery during the charging process, thereby making the battery temperature greater than or equal to a preset battery temperature.

[0099] As another possible implementation, this solution can use pulse rapid heating to increase the temperature of the battery. Specifically, the computing device can calculate the temperature difference between the battery temperature of the secondary battery and the preset battery temperature, determine the externally connected resistance based on the temperature difference, and determine the required pulse current value based on the externally connected resistance data, thereby achieving the temperature increase of the secondary battery through the pulse current and the externally connected resistance, so that the battery temperature is greater than or equal to the preset battery temperature.

[0100] As another possible embodiment, this solution can use hydrothermal means to heat the secondary battery. For example, as shown in the battery module schematic diagram of FIG4 , the battery pack may include a battery housing A1, a secondary battery A2, and a temperature regulating mechanism. The temperature regulating mechanism is used to maintain the battery temperature of the secondary battery greater than or equal to a preset battery temperature. As a specific example, the temperature regulating structure can be a heating mechanism, such as a hydrothermal pipe A4 as shown in FIG4 . The hydrothermal pipe A4 is arranged around the secondary battery A2 and is located within the battery housing A1. The hydrothermal pipe A4 is connected to a control valve A5 (not shown in the figure). The control valve A5 can be a solenoid valve or other valve with controllable opening.

[0101] Based on the above structure, the computing device can be electrically connected to the control valve A5. When adjusting the battery temperature, the computing device can control the control valve A5 to open, allowing hot water to enter the water heating pipe A4. The water heating pipe A4 surrounding the battery pack A2 heats up the entire secondary battery, thereby gradually increasing the battery temperature and maintaining the battery temperature of the secondary battery greater than or equal to the preset battery temperature.

[0102] Furthermore, the computing device can calculate the temperature difference between the battery temperature of the secondary battery and a preset battery temperature, and then control the opening of the control valve A5 based on the temperature difference to control the temperature regulation mode, thereby achieving controllable temperature rise of the secondary battery. Different openings of the control valve A5 correspond to different temperature regulation modes. For example, a larger opening of the control valve A5 increases the temperature regulation mode and increases the speed of the secondary battery's temperature rise; a smaller opening of the control valve A5 decreases the temperature regulation mode and decreases the speed of the secondary battery's temperature rise. This achieves controllable temperature adjustment of the secondary battery, avoiding the impact of excessively rapid temperature regulation on the secondary battery's lifespan, and preventing the problem of slow charging rate caused by excessively slow temperature regulation.

[0103] It should be noted that due to the temperature difference between the secondary battery and the operating or external environment, the secondary battery may experience temperature loss during the charging process. To maintain the battery temperature of the secondary battery at or above the preset battery temperature, the temperature adjustment method designed in this solution can be continuously implemented. For example, this solution can continuously open the control valve during the charging process of the secondary battery, so that the water heating pipe heats the secondary battery throughout the charging process, thereby compensating for the temperature loss that may occur during the charging process and ensuring that the secondary battery is always charged at a temperature that is greater than or equal to the preset battery temperature.

[0104] As another possible embodiment, this solution can raise the temperature of the secondary battery to a higher temperature value all at once. On this basis, the temperature loss during the charging process of the secondary battery will not cause the battery temperature of the secondary battery to fall below the preset battery temperature during the charging process, thereby ensuring that the secondary battery is always charged at a temperature greater than or equal to the preset battery temperature. For example, if the preset battery temperature is 40°C, this solution can raise the battery temperature of the secondary battery to 55°C all at once. In this way, although the secondary battery may experience temperature loss during the charging process, the temperature of the secondary battery will not fall below the preset battery temperature until charging is completed, thereby ensuring that the secondary battery is always charged at a temperature greater than or equal to the preset battery temperature.

[0105] This embodiment first calculates the temperature difference between the battery temperature of the secondary battery and the preset battery temperature, adjusts the opening of the control valve according to the temperature difference, and controls the temperature regulation method. The battery temperature of the secondary battery is adjusted according to the temperature regulation method, so that the temperature of the secondary battery continues to rise and is greater than or equal to the preset voltage temperature. Therefore, this solution controls the opening of the control valve through the temperature difference, thereby achieving controllable secondary battery temperature adjustment, avoiding the impact of too fast temperature regulation on the life of the secondary battery, and avoiding the problem of low charging rate caused by too slow temperature regulation.

[0106] As described above, a computing device (eg, a battery management system BMS) can obtain the open circuit voltage of a secondary battery and determine a corresponding SOC value based on the obtained open circuit voltage.

[0107] On the basis of the above, when charging the secondary battery, the computing device may determine the charging method of the secondary battery according to the SOC value of the secondary battery and a preset value.

[0108] As a possible implementation, the computing device may determine whether the SOC value of the secondary battery is greater than or equal to a preset value; if it is determined that the SOC value of the secondary battery is greater than or equal to the preset value, the secondary battery is constant-current charged with a first constant-current charging current; and when the real-time voltage of the constant-current charging is greater than or equal to the first constant-voltage charging voltage, the secondary battery is constant-voltage charged with the first constant-voltage charging voltage until the current of the secondary battery is greater than or equal to the preset cut-off current.

[0109] As another possible implementation, the computing device may determine whether the SOC value of the secondary battery is less than a preset value; if it is determined that the SOC value of the secondary battery is less than the preset value, the secondary battery is preliminarily charged, and after the SOC value of the secondary battery is greater than or equal to the value, the secondary battery is constant-current charged with a second constant-current charging current, and when the real-time voltage of the constant-current charging is greater than or equal to the second constant-voltage charging voltage, the secondary battery is constant-voltage charged with a second constant-voltage charging voltage until the current of the secondary battery is greater than or equal to the preset cut-off current.

[0110] As a possible embodiment, the aforementioned first constant-current charging current and the second constant-current charging current can be set to the same value, and the first constant-voltage charging voltage and the second constant-voltage charging voltage can be set to the same value, wherein the first constant-current charging current and the second constant-current charging current can be any current in the first preset current range, the first constant-voltage charging voltage and the second constant-voltage charging voltage can be any voltage in the first preset voltage range, and the preset cut-off current can also be any current in the preset cut-off current range.

[0111] The first preset current interval, the first preset voltage interval, and the preset cut-off current interval can all be adaptively set according to actual parameters of the secondary battery.

[0112] Specifically, the first preset current interval designed in this solution may include a current interval of 0.1C-20C, where C is the battery capacity of the secondary battery. On this basis, the first constant current charging current and the second constant current charging current may be any one of 0.1C, 0.2C, 0.3C, 0.5C, 1C, 2C, 5C, 10C, 12C, 15C, 19C and 20C.

[0113] The first preset voltage interval may include a voltage interval of 3.95V-4.35V. On this basis, the first constant voltage charging voltage and the second constant voltage charging voltage may be any one of 3.95V, 3.96V, 4V, 4.1V, 4.2V, 4.3V and 4.35V.

[0114] The preset cutoff current range can specifically be 0.01C-0.2C. On this basis, the preset cutoff current can be any one of 0.01C, 0.02C, 0.05C, 0.1C, 0.15C, 0.19C, and 0.2C. Of course, in addition to the preset cutoff current ranges listed above, the preset cutoff current range can also include any one of 0.01C-0.19C, 0.02C-0.18C, 0.03C-0.17C, 0.05C-0.15C, 0.07C-0.12C, and 0.09C-0.1C.

[0115] It should be noted here that the above is an example in which the first constant-current charging current and the second constant-current charging current are set to the same value, and the first constant-voltage charging voltage and the second constant-voltage charging voltage are set to the same value. In this scheme, the first constant-current charging current and the second constant-current charging current can also be different values, and the first constant-voltage charging voltage and the second constant-voltage charging voltage can also be different values. This scheme does not limit this and can be adaptively adjusted according to actual application scenarios.

[0116] In the embodiment of the present application, when the SOC value of the secondary battery is greater than or equal to a preset value, the secondary battery is charged with constant current. When the real-time voltage of the secondary battery is greater than or equal to the first constant voltage charging voltage during the constant current charging process, the secondary battery is charged with constant voltage using the first constant voltage charging voltage. Thus, by charging in a constant current followed by a constant voltage manner, the influence of polarization of the battery cell during constant current charging on the capacity of the secondary battery is eliminated, thereby increasing the capacity of the secondary battery. When the SOC value is less than a preset value, preliminary charging is performed. After the SOC value is greater than or equal to the preset value, charging is performed in a constant current followed by a constant voltage manner. Thus, different charging methods are adopted at different stages to increase the capacity of the secondary battery while increasing the charging rate of the secondary battery.

[0117] According to some embodiments of the present application, it is described above that when the SOC value of the secondary battery is less than a preset value, the secondary battery is preliminarily charged. As a possible implementation, this solution can use a third constant current charging current to perform constant current charging on the secondary battery.

[0118] Among them, the third constant current charging current can be any current in the second preset current interval, and the second preset current interval can be adaptively adjusted according to the actual battery parameters of the secondary battery. The second preset current interval designed in this scheme may include any preset current interval of 0.1C-20C, 0.2C-20C, 0.2C-19.9C, 0.3C-19.5C, 0.5C-19C, 1C-18.5C, 1.5C-18C, 2C-17.5C, 2.5C-17C, 3C-16.5C, 3.5C-16C, 4C-15C, 5C-14C, 7C-13C, 8C-12C, 9C-11C, and 9C-10C.

[0119] On the basis of the above, the third constant current charging current can be any one of 0.1C, 0.2C, 0.3C, 0.5C, 1C, 1.5C, 2C, 2.5C, 3C, 3.5C, 4C, 5C, 7C, 8C, 9C, 11C, 12C, 14C, 15C, 16C, 16.5C, 17C, 17.5C, 18C, 18.5C, 19C, 19.5C, 19.9C and 20C.

[0120] As another possible implementation, this solution may also use a third constant-voltage charging voltage to perform constant-voltage charging on the secondary battery.

[0121] Among them, the third constant-voltage charging voltage is any voltage in the second preset voltage interval. The second preset voltage interval can be adaptively adjusted according to the actual battery parameters of the secondary battery. The second preset voltage interval designed in this solution can be a voltage of not less than 3.25V, and preferably a voltage of not less than 3.5V. For example, the second preset voltage interval can be any preset voltage interval of 3.25V-3.5V, 3.3V-3.4V, 3.25V-3.4V, 3.5V-4V, and 3.5V-4.32V. On this basis, the third constant-voltage charging voltage can adopt any one of 3.25V, 3.3V, 3.35V, 3.4V, 3.45V, 3.5V, 4V, 4.2V, and 4.32V.

[0122] This embodiment performs preliminary charging on the secondary battery by adopting a constant current or constant voltage method, thereby achieving rapid charging of the secondary battery.

[0123] According to some embodiments of the present solution, since the positive electrode active material adopts a secondary battery of lithium iron manganese phosphate, when charging, it first passes through the platform of the iron delithiation process and then passes through the platform of the manganese delithiation process. Since the low charging rate is mainly due to the slow delithiation speed caused by the embedding of manganese, therefore, in order to save power consumption and make the charging rate improvement brought about by the temperature rise more accurate and effective, the preset value designed in the present solution can be determined according to the iron content ratio of the iron-manganese ratio in the positive electrode active material.

[0124] As a possible implementation method, the preset value described above can be determined based on the molar fraction f of the iron element in the iron and manganese elements in the active material. The molar fraction of the iron element refers to the ratio of the molar content of the iron element to the sum of the molar content of the iron element and the molar content of the manganese element. For example, if the molar content of the iron element is Mol1 and the molar content of the manganese element is Mol2, then f is Mol1: (Mol1+Mol2). Specifically, the preset value can be set to fS, where S is the SOC value of the secondary battery in a fully charged state. Among them, under normal circumstances, the SOC value of the secondary battery in a fully charged state is generally 1, that is, S is generally a value of 1; but with the use and loss of the secondary battery, the SOC value of the secondary battery in a fully charged state may be less than 1, such as 0.99, 0.98, 0.97, 0.96 and 0.95, etc. On this basis, the S designed in this solution also changes accordingly with the change of the SOC value of the secondary battery in a fully charged state.

[0125] The value range of f can be 0.001-0.5, for example, the value of f is any one of 0.002-0.5, 0.003-0.5, 0.004-0.5, 0.005-0.5, 0.005-0.49, 0.007-0.45, 0.008-0.45, 0.009-0.45, 0.01-0.45, 0.02-0.4, 0.05-0.35, 0.07-0.3, 0.1-0.25, 0.1-0.2, and 0.15-0.2.

[0126] Specifically, f can be any one of 0.001, 0.002, 0.003, 0.004, 0.005, 0.007, 0.008, 0.009, 0.01, 0.02, 0.05, 0.07, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.49, and 0.5.

[0127] For example, assuming that the value of f is 0.3, then the iron-manganese ratio of lithium iron manganese phosphate is 3:7, and the preset voltage threshold is 0.3S, that is, the preset voltage threshold is 30% of the SOC value of the secondary battery when it is fully charged; for another example, assuming that the value of f is 0.4, then the iron-manganese ratio of lithium iron manganese phosphate is 4:6, and the preset voltage threshold is 0.4S, that is, the preset voltage threshold is 40% of the SOC value of the secondary battery when it is fully charged.

[0128] In addition, it should be noted that the above-mentioned values ​​of f are all less than or equal to 0.5, that is, the proportion of iron is less than or equal to the proportion of manganese. In addition to the above-mentioned values, the implementation scheme of the present invention may also have an iron content slightly higher than the manganese content. For example, the value of f may also be 0.5-0.6, for example, any one of 0.51, 0.52, 0.55, 0.57, 0.58, 0.59, and 0.6.

[0129] As another possible implementation, in addition to using the iron ratio to determine the preset value, this solution can also use the manganese ratio to determine the preset value. The method of determining the manganese ratio is similar to that of determining the iron ratio and will not be repeated here.

[0130] The M in the cathode material LiMPO4 designed in this scheme may include Mn and Fe elements. As a possible implementation method, LiMPO4 may be a compound LiMn 1-y Fe y PO4.

[0131] For example, the compound LiMn 0.80 Fe 0.20 The preparation method of PO4 includes:

[0132] Step S1: preparing Fe-doped manganese oxalate.

[0133] 919.4g of manganese carbonate and 231.7g of ferrous carbonate were added to a mixer and thoroughly mixed for 6 hours. The resulting mixture was then transferred to a reactor, and 5L of deionized water and 1260.6g of oxalic acid dihydrate were added. The mixture was heated to 80°C and stirred at 500 rpm for 6 hours, mixing until the reaction terminated and no bubbles were generated, resulting in an Fe-doped manganese oxalate suspension. The suspension was then filtered, dried at 120°C, and sand-milled to obtain ferromanganese oxalate particles with a particle size of 100nm.

[0134] Step S2: Preparation of LiMn 0.80 Fe 0.20 PO4.

[0135] Take the manganese oxalate iron (C2O4Mn 0.80 Fe 0.201791.4 g of 1,000 g of 1,000 g of 1,000 g of 1,000 g of 1,000 g of 2,000 g of 1,000 g of 1,000 g of 2,000 g of 1,000 g of 1,000 g of 4,000 g of 1,000 g of 2,000 g of 1 ...1,000 g of 2,000 g of 1,000 g of 1,000 g of 2,000 g of 1,000 g of 1,000 g of 2,000 g of 1,000 g of 1,000 g of 2,000 g of 1,000 g of 1,000 g of 1,000 g of 2,000 g of 1,000 g of 1,000 g of 1,000 g of 1,000

[0136] The positive electrode active material may be a material having the chemical formula Li 1+t Mn 1-c Fe c P 1-z R z O4 compound, wherein t is any value in the range of -0.100 to 0.100, c is any value in the range of 0.001 to 0.500, z is any value in the range of 0.001 to 0.100, and R includes one or more elements selected from B (boron), S, Si and N. Wherein, the values ​​of t, c and z satisfy the following conditions: the entire compound remains electrically neutral. The ratio of c to 1-c is 1:10 to 1:1, and can be optionally 1:4 to 1:1. Here c represents the sum of the stoichiometric numbers of the Mn-site doping element Fe. In some embodiments, the ratio of z to 1-z is 1:9 to 1:999, and can be optionally 1:499 to 1:249. Here z represents the sum of the stoichiometric numbers of the P-site doping element R.

[0137] Compound Li 1+t Mn 1-c Fe c P 1-z R z The preparation method of O4 may include the following steps:

[0138] (1) dissolving a manganese source, an iron source, and an acid in a solvent and stirring to generate a suspension of a manganese salt doped with elemental Fe, filtering the suspension and drying the filter cake to obtain a manganese salt doped with elemental Fe; (2) adding a lithium source, a phosphorus source, a source of elemental R, a solvent, and the manganese salt doped with elemental Fe obtained in step (1) into a reaction vessel, grinding and mixing to obtain a slurry; (3) transferring the slurry obtained in step (2) to a spray drying device for spray drying and granulation to obtain particles; (4) sintering the particles obtained in step (3) to obtain a positive electrode active material.

[0139] In any embodiment, the manganese source can be a manganese-containing substance known in the art that can be used to prepare lithium manganese phosphate. For example, the manganese source can be selected from one or a combination of elemental manganese, manganese dioxide, manganese phosphate, manganese oxalate, and manganese carbonate. The iron source is selected from at least one of elemental iron, oxides, phosphates, oxalates, carbonates, and sulfates. The acid is selected from one or more of hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, and organic acids such as oxalic acid, and can be, for example, oxalic acid. The source of element R is selected from at least one of sulfates, borates, nitrates, and silicates of element R.

[0140] For example, the compound Li 1.001 Mn 0.999 Fe 0.001 P 0.999 Si 0.001 The preparation method of O4 includes:

[0141] Step S1: preparing Fe-doped manganese oxalate.

[0142] 1148.2g of manganese carbonate and 1.2g of ferrous carbonate were added to a mixer and thoroughly mixed for 6 hours. The resulting mixture was then transferred to a reactor, and 5L of deionized water and 1260.6g of oxalic acid dihydrate were added. The mixture was heated to 80°C and stirred at 500 rpm for 6 hours, mixing until the reaction terminated and no bubbles were generated, resulting in an Fe-doped manganese oxalate suspension. The suspension was then filtered, dried at 120°C, and sand-milled to obtain ferromanganese oxalate particles with a particle size of 100nm.

[0143] Step S2: Preparation of Li 1.001 Mn 0.999 Fe 0.001 P 0.999 Si 0.001 O4.

[0144] Take the manganese oxalate iron (C2O4Mn 0.999 Fe 0.001 1789.6 g of 2H2O (calculated as 2H2O), 369.8 g of lithium carbonate, 1148.9 g of ammonium dihydrogen phosphate, and 0.8 g of silicic acid were added to 20 L of deionized water, stirred thoroughly, and uniformly mixed at 80°C for 10 hours to obtain a slurry. The slurry was transferred to a spray dryer for spray drying and granulation, and then dried at 250°C to obtain a powder. The powder was sintered in a roller kiln at 700°C for 4 hours in a protective atmosphere (90% nitrogen and 10% hydrogen).

[0145] In other embodiments, the positive electrode active material may be a material having the chemical formula Li 1+w C m Mn 1-u Fe u P1-a R a O 4-n D n A compound wherein C comprises one or more elements selected from Zn, Al, Na, K, Mg, Nb, Mo, and W, R comprises one or more elements selected from B (boron), S, Si, and N, D comprises one or more elements selected from S, F, Cl, and Br, w is any value in the range of -0.100 to 0.100, u is any value in the range of 0.001 to 0.500, a is any value in the range of 0.001 to 0.100, n is any value in the range of 0.001 to 0.1, and m is any value in the range of 0.9 to 1.1. Similarly, the values ​​of w, u, a, and m satisfy the following condition: the entire compound remains electrically neutral.

[0146] Compound Li 1+w C m Mn 1-u Fe u P 1-a R a O 4-n D n The preparation method may include the following steps:

[0147] (1) dissolving a manganese source, an iron source, and an acid in a solvent and stirring to generate a suspension of a manganese salt doped with elemental Fe, filtering the suspension and drying the filter cake to obtain a manganese salt doped with elemental Fe; (2) adding a lithium source, a phosphorus source, a source of element C, a source of element R, a source of element D, a solvent, and the manganese salt doped with elemental Fe obtained in step (1) into a reaction vessel, grinding and mixing to obtain a slurry; (3) transferring the slurry obtained in step (2) to a spray drying device for spray drying and granulation to obtain particles; (4) sintering the particles obtained in step (3) to obtain a positive electrode active material.

[0148] In any embodiment, the source of element C is selected from at least one of a simple substance, oxide, phosphate, oxalate, carbonate, and sulfate of element C. The manganese source can be a manganese-containing substance known in the art that can be used to prepare lithium manganese phosphate, for example, the manganese source can be selected from one or a combination of simple manganese, manganese dioxide, manganese phosphate, manganese oxalate, and manganese carbonate. The iron source is selected from at least one of a simple substance, oxide, phosphate, oxalate, carbonate, and sulfate of iron. The acid is selected from one or more of hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, and an organic acid such as oxalic acid, for example, oxalic acid. The source of element R is selected from at least one of sulfate, borate, nitrate, and silicate of element R, and the source of element D is selected from at least one of a simple substance and an ammonium salt of element D.

[0149] The positive electrode active material may contain Li 1+w Cm Mn 1-u Fe u P 1-a R a O 4-n D n An embodiment of the present invention is provided, wherein the size of x is affected by the valence of Fe and R and the size of y and z to ensure that the entire system is electrically neutral. If the value of x is too small, the lithium content of the entire system will be reduced, affecting the gram capacity of the material. The y value will limit the total amount of all doping elements. If y is too small, that is, the doping amount is too little, the doping element will not work. If y exceeds 0.5, the Mn content in the system will be low, affecting the voltage platform of the material. The R element is doped in the position of P. Since the PO tetrahedron is relatively stable, and a large z value will affect the stability of the material, the a value is limited to 0.001 to 0.100. More specifically, w is any value in the range of -0.100 to 0.100, u is any value in the range of 0.001 to 0.500, a is any value in the range of 0.001 to 0.100, n is any value in the range of 0.001 to 0.1, and m is any value in the range of 0.9 to 1.1. For example, the 1+x is selected from the range of 0.9 to 1.1, for example, 0.97, 0.977, 0.984, 0.988, 0.99, 0.991, 0.992, 0.993, 0.994, 0.995, 0.996, 0.997, 0.998, 1.01, the x is selected from the range of 0.001 to 0.1, for example, 0.001, 0.005, the y is selected from the range of 0.001 to 0.5, for example, 0.001 , 0.005, 0.02, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.34, 0.345, 0.349, 0.35, 0.4, the z is selected from the range of 0.001 to 0.1, for example, 0.001, 0.005, 0.08, 0.1, the n is selected from the range of 0.001 to 0.1, for example, 0.001, 0.005, 0.08, 0.1, and the positive electrode active material is electrically neutral.

[0150] Unless otherwise specified, in the above chemical formula, when a doping site has two or more elements, the above numerical ranges for w, u, a or m are not only limited to the stoichiometric number of each element as the site, but also to the sum of the stoichiometric numbers of the elements as the site. For example, when the chemical formula is Li 1+w Mn 1-u Fe u P 1-a R aFor compounds containing O4, when R is two or more elements R1, R2, ..., Rn, the stoichiometric numbers z1, z2, ..., zn of R1, R2, ..., Rn must each fall within the numerical range for z defined in this application, and the sum of z1, z2, ..., zn must also fall within this numerical range. Similarly, for the case where C is two or more elements, the numerical range for the stoichiometric number of C defined in this application also has the above meaning.

[0151] The preset value designed in this embodiment is determined according to the iron content ratio of the iron-to-manganese ratio in the positive electrode active material of the secondary battery, so that when the SOC of the secondary battery is greater than or equal to the preset value, it has crossed the iron delithiation platform and entered the manganese delithiation platform, that is, the secondary battery is heated just after entering the manganese delithiation platform, thereby making the timing of the temperature increase more accurate, and thus making the charging rate of the secondary battery more accurate and effective while wasting less power consumption.

[0152] According to some embodiments of the present solution, the preset battery temperature described above may be any temperature within a preset temperature range, wherein the preset temperature range may be adaptively adjusted according to actual conditions.

[0153] The preset temperature range designed in this scheme may include any one of 30℃-150℃, 30℃-140℃, 30℃-130℃, 30℃-120℃, 30℃-110℃, 30℃-100℃, 30℃-90℃, 30℃-80℃, 30℃-70℃, 30℃-60℃, 30℃-50℃, 40℃-50℃, 40℃-45℃, 50℃-80℃, 50℃-70℃, and 50℃-60℃.

[0154] Specifically, the preset battery temperature can be 30℃, 32℃, 35℃, 38℃, 40℃, 42℃, 45℃, 47℃, 48℃, 50℃, 52℃, 54℃, 55℃, 58℃, 60℃, 63℃, 65℃, 70℃, 72℃, 75℃, 78℃, 80℃, 82℃, 85℃, 88℃, 90℃, 93℃, 95℃, 98℃, etc. ℃, 100℃, 103℃, 105℃, 108℃, 110℃, 112℃, 115℃, 117℃, 120℃, 122℃, 125℃, 126℃, 128℃, 130℃, 132℃, 134℃, 136℃, 138℃, 140℃, 142℃, 143℃, 145℃, 147℃ and 150℃.

[0155] FIG5 and FIG6 are data and broken line diagrams of the discharge capacity and charge capacity of a secondary battery at different charging temperatures. The diagrams in FIG5 and FIG6 are obtained by testing the following secondary batteries using the following test method:

[0156] The secondary battery's positive electrode sheet (materials / binder / conductive agent and their contents / compacted density / thickness) is composed of: 97.3% M3P + 2.2% PVDF + 0.5% SP, compacted to 2.35°C, and 213µm thick. The negative electrode material (materials / binder / conductive agent and their contents / compacted density / thickness) is composed of: 96.5% graphite + 1.3% SBR + 1.1% CMC + 0.4% SP, compacted to 1.65°C, and 142µm thick. The electrolyte (solvent / electrolyte / additive / lithium salt and their contents) is prepared by uniformly dissolving LiPF6 in a mixture of ethylene carbonate, dimethyl carbonate, and 1,2-propylene glycol carbonate in a volume ratio of 1:1:1. The concentration of LiPF6 in the electrolyte is 1 mol / L.

[0157] The test method is: take charging and discharging at 25℃ as an example: place the battery cell in a constant temperature oven at 25℃, let it stand for 2h, discharge it to 2.5V at 0.33C, then discharge it to 2.0V at 0.02C, then let it stand for 2h, charge it to 4.3V at 0.33C and then CV to the cut-off current 0.05C (this step is the charging capacity corresponding to 25℃), let it stand for 2h, discharge it to 2.0V at 0.33C (this step is the discharge capacity at 25℃), and then change the temperature of the constant temperature oven respectively, so that the test results shown in Figures 5 and 6 can be obtained.

[0158] As can be seen from Figures 5 and 6, at 25°C (normal temperature), the discharge capacity of the secondary battery is 0.119Ah and the charging capacity is 0.119Ah; at 40°C, the discharge capacity is 0.132Ah and the charging capacity is 0.131Ah; at 50°C, the discharge capacity is 0.130Ah and the charging capacity is 0.132Ah; at 60°C, the discharge capacity is 0.133Ah and the charging capacity is 0.134Ah; at 70°C, the discharge capacity is 0.136Ah and the charging capacity is 0.137Ah; and at 80°C, the discharge capacity is 0.139Ah and the charging capacity is 0.139Ah.

[0159] As can be seen from Figures 5 and 6, as the charging temperature of the battery increases (especially when the temperature is raised to 40°C or above), the charging capacity and discharge capacity of the secondary battery also continue to increase. Therefore, the charging temperature of the battery will not only affect the charging capacity and discharge capacity of the secondary battery, but as the charging temperature increases, the charging capacity and discharge capacity of the secondary battery will also increase, thereby effectively utilizing the capacity.

[0160] However, in order to ensure the life of the secondary battery and a good working environment, the preset battery temperature designed in this scheme may preferably adopt three ranges of 30℃-90℃, 30℃-80℃ and 40℃ to 45℃, and the most preferred range is 40℃ to 45℃. When the temperature of the secondary battery is within the range of 40℃ to 45℃, the secondary battery can be quickly charged and its capacity can be effectively utilized without being affected by high temperature.

[0161] In this embodiment, the preset battery temperature is designed to be any temperature in a preset temperature range, and the preset temperature range is any one of 30°C to 90°C, 30°C to 80°C, and 40°C to 50°C, so that the life of the secondary battery and the operation of the entire vehicle are not affected by high temperature, and the secondary battery can be quickly charged and its capacity can be effectively utilized.

[0162] FIG7 shows a schematic structural block diagram of a charging device provided by the present application. It should be understood that the device corresponds to the method embodiment executed in FIG1 to FIG6 and can execute the steps involved in the aforementioned method. The specific functions of the device can be found in the description above. To avoid repetition, a detailed description is omitted here. The device includes at least one software function module that can be stored in a memory in the form of software or firmware or solidified in the operating system (OS) of the device. Specifically, the device includes: a charging module 700 and a maintenance module 710; the charging module 700 is used to charge the secondary battery; the maintenance module 710 is used to maintain the battery temperature of the secondary battery greater than or equal to the preset battery temperature during the charging process of the secondary battery; wherein the positive electrode active material of the secondary battery includes LiMPO4, wherein M includes Mn and Fe elements.

[0163] In the technical solution of the embodiment of the present application, during the charging process of the secondary battery, the solution maintains the battery temperature of the secondary battery greater than or equal to the preset battery temperature. Since the preset battery temperature of the solution can be designed to be greater than the temperature of the normal temperature environment, the solution can enable the secondary battery to be charged in a higher battery temperature environment. After the charging temperature of the secondary battery is increased, the delithiation depth of the positive electrode active material lithium manganese iron phosphate in the secondary battery can be correspondingly increased, thereby increasing the capacity of the secondary battery; at the same time, in an environment higher than the preset battery temperature, the diffusion rate and delithiation rate of lithium ions are increased, thereby reducing the charging time of the secondary battery, increasing the charging rate of the secondary battery, and meeting the needs of fast charging.

[0164] According to some embodiments of the present application, optionally, the maintaining module 710 is specifically configured to maintain the battery temperature of the secondary battery greater than or equal to a preset battery temperature during the entire process of charging the secondary battery.

[0165] According to some embodiments of the present application, optionally, the maintaining module 710 is further specifically configured to maintain the battery temperature of the secondary battery greater than or equal to a preset battery temperature during a portion of the charging process of the secondary battery.

[0166] According to some embodiments of the present application, optionally, the maintaining module 710 is further specifically configured to maintain the battery temperature of the secondary battery greater than or equal to a preset battery temperature after the SOC of the secondary battery reaches a preset value.

[0167] According to some embodiments of the present application, the maintaining module 710 is further specifically configured to maintain the battery temperature of the secondary battery greater than or equal to a preset battery temperature after the charging time of the secondary battery reaches a preset time.

[0168] According to some embodiments of the present application, the maintenance module 710 is further specifically used to obtain the battery temperature of the secondary battery; if it is determined that the battery temperature of the secondary battery is lower than the preset battery temperature, the secondary battery is heated to make the battery temperature of the secondary battery higher than or equal to the preset battery temperature.

[0169] According to some embodiments of the present application, the maintenance module 710 is further specifically used to calculate the temperature difference between the battery temperature of the secondary battery and the preset battery temperature; obtain a temperature adjustment method based on the temperature difference; and heat the secondary battery according to the temperature adjustment method to maintain the battery temperature of the secondary battery greater than or equal to the preset battery temperature.

[0170] In some embodiments, the maintenance module 710 is further specifically used to obtain the battery temperature of the secondary battery and / or the SOC value of the secondary battery; if it is determined that the battery temperature of the secondary battery is lower than the preset battery temperature and / or the SOC value of the secondary battery is lower than the preset value, the secondary battery is heated to make the battery temperature of the secondary battery higher than or equal to the preset battery temperature.

[0171] According to some embodiments of the present application, the secondary battery includes a battery casing, a battery body and a hydrothermal pipe; the hydrothermal pipe is arranged around the battery body and is connected to the control valve; the maintenance module 710 is also specifically used to adjust the opening of the control valve according to the temperature difference to control the temperature regulation method.

[0172] According to some embodiments of the present application, the charging module 700 is further specifically configured to obtain an SOC value of the secondary battery; and determine a charging method for the secondary battery according to the SOC value of the secondary battery and a preset value.

[0173] According to some embodiments of the present application, the charging module 700 is further specifically used to determine whether the SOC value of the secondary battery is greater than or equal to a preset value; if it is determined that the SOC value of the secondary battery is greater than or equal to the preset value, the secondary battery is constant-current charged with a first constant-current charging current; and when the real-time voltage of the constant-current charging is greater than or equal to the first constant-voltage charging voltage, the secondary battery is constant-voltage charged with the first constant-voltage charging voltage until the current of the secondary battery is greater than or equal to the preset cut-off current.

[0174] According to some embodiments of the present application, the charging module 700 is further specifically used to determine whether the SOC value of the secondary battery is less than a preset value; if it is determined that the SOC value of the secondary battery is less than the preset value, the secondary battery is preliminarily charged, and after the SOC value of the secondary battery is greater than or equal to the preset value, the secondary battery is constant-current charged using a second constant-current charging current, and when the real-time voltage of the constant-current charging is greater than or equal to the second constant-voltage charging voltage, the secondary battery is constant-voltage charged using the second constant-voltage charging voltage until the current of the secondary battery is greater than or equal to the preset cut-off current.

[0175] According to some embodiments of the present application, the charging module 700 is further specifically configured to perform constant-current charging on the secondary battery using a third constant-current charging current; or perform constant-voltage charging on the secondary battery using a third constant-voltage charging voltage.

[0176] According to some embodiments of the present application, as shown in Figure 8, the present application provides an electronic device 8, including: a processor 801 and a memory 802, the processor 801 and the memory 802 are interconnected and communicate with each other through a communication bus 803 and / or other forms of connection mechanisms (not marked), and the memory 802 stores a computer program executable by the processor 901. When the computing device is running, the processor 801 executes the computer program to execute the method executed by the external terminal in any optional implementation method, such as steps S200 to S220: charging the secondary battery, and during the charging process of the secondary battery, maintaining the battery temperature of the secondary battery greater than or equal to the preset battery temperature.

[0177] The present application provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the method in any of the aforementioned optional implementations is executed.

[0178] Among them, the storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk or optical disk.

[0179] The present application provides a computer program product. When the computer program product is run on a computer, the computer is enabled to execute the method in any optional implementation manner.

[0180] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A charging method, characterized in that: The method comprises: charging the secondary battery; During charging of the secondary battery, maintaining a battery temperature of the secondary battery greater than or equal to a preset battery temperature; The positive electrode active material of the secondary battery includes LiMPO4, wherein M includes Mn and Fe elements.

2. The method according to claim 1, characterized in that The positive electrode material includes at least one of the following materials: LiMn 1-y Fe y PO4,y is any value in the range of 0.001 to 0.5; Li 1+t Mn 1-c Fe c P 1-z R z O4, t is any value in the range of -0.100 to 0.100, c is any value in the range of 0.001 to 0.500, z is any value in the range of 0.001 to 0.100, and R includes one or more elements selected from B, S, Si and N; Li 1+w C m Mn 1-u Fe u P 1-a R a O 4-n D n , wherein the C includes one or more elements selected from Zn, Al, Na, K, Mg, Nb, Mo and W, the R includes one or more elements selected from B, S, Si and N, the D includes one or more elements selected from S, F, Cl and Br, w is any value in the range of -0.100 to 0.100, u is any value in the range of 0.001 to 0.500, a is any value in the range of 0.001 to 0.100, n is any value in the range of 0.001 to 0.1, and m is any value in the range of 0.9 to 1.

1.

3. The method according to any one of claims 1 to 2, characterized in that: The method of maintaining the battery temperature of the secondary battery greater than or equal to a preset battery temperature during charging of the secondary battery includes: During the entire process of charging the secondary battery, the battery temperature of the secondary battery is maintained to be greater than or equal to a preset battery temperature.

4. The method according to any one of claims 1 to 2, characterized in that: The method of maintaining the battery temperature of the secondary battery greater than or equal to a preset battery temperature during charging of the secondary battery includes: During a partial process of charging the secondary battery, a battery temperature of the secondary battery is maintained to be greater than or equal to a preset battery temperature.

5. The method according to claim 4, characterized in that The method of maintaining the battery temperature of the secondary battery greater than or equal to a preset battery temperature during a portion of the charging process of the secondary battery comprises: After the SOC of the secondary battery reaches a preset value, the battery temperature of the secondary battery is maintained to be greater than or equal to the preset battery temperature.

6. The method according to claim 4, characterized in that The method of maintaining the battery temperature of the secondary battery greater than or equal to a preset battery temperature during a portion of the charging process of the secondary battery comprises: After the charging time of the secondary battery reaches a preset time, the battery temperature of the secondary battery is maintained to be greater than or equal to a preset battery temperature.

7. The method according to any one of claims 1 to 2, characterized in that: The maintaining the battery temperature of the secondary battery greater than or equal to a preset battery temperature includes: Acquiring a battery temperature of the secondary battery; If it is determined that the battery temperature of the secondary battery is lower than the preset battery temperature, the secondary battery is heated to increase the temperature so that the battery temperature of the secondary battery is higher than or equal to the preset battery temperature.

8. The method according to claim 7, characterized in that The heating of the secondary battery comprises: Calculating a temperature difference between a battery temperature of the secondary battery and a preset battery temperature; Acquire a temperature adjustment method according to the temperature difference; The secondary battery is heated according to the temperature adjustment method to maintain the battery temperature of the secondary battery greater than or equal to a preset battery temperature.

9. The method according to claim 8, characterized in that in, The secondary battery is provided with a water heating pipeline, and the water heating pipeline is connected to the control valve; The obtaining of the temperature adjustment method according to the temperature difference comprises: The opening of the control valve is adjusted according to the temperature difference to control the temperature adjustment mode.

10. The method according to any one of claims 1 to 2, characterized in that: The charging of the secondary battery comprises: Obtaining an SOC value of the secondary battery; A charging method of the secondary battery is determined according to the SOC value of the secondary battery and a preset value.

11. The method according to claim 10, characterized in that The step of determining a charging method of the secondary battery according to the SOC value of the secondary battery and a preset value includes: Determining whether the SOC value of the secondary battery is greater than or equal to a preset value; If it is determined that the SOC value of the secondary battery is greater than or equal to a preset value, the first constant current charging current is used to perform constant current charging on the secondary battery; and when the real-time voltage of the constant current charging is greater than or equal to the first constant voltage charging voltage, the first constant voltage charging voltage is used to perform constant voltage charging on the secondary battery until the current of the secondary battery is greater than or equal to the preset cut-off current.

12. The method according to claim 10, characterized in that The step of determining a charging method of the secondary battery according to the SOC value of the secondary battery and a preset value includes: Determine whether the SOC value of the secondary battery is less than a preset value; If it is determined that the SOC value of the secondary battery is less than a preset value, the secondary battery is preliminarily charged, and after the SOC value is greater than or equal to the preset value, the secondary battery is constant-current charged with a second constant-current charging current, and when the real-time voltage of the constant-current charging is greater than or equal to the second constant-voltage charging voltage, the secondary battery is constant-voltage charged with a second constant-voltage charging voltage until the current of the secondary battery is greater than or equal to the preset cut-off current.

13. The method according to claim 12, characterized in that The preliminary charging of the secondary battery comprises: Using a third constant current charging current to perform constant current charging on the secondary battery; or The secondary battery is charged at a constant voltage using a third constant voltage charging voltage.

14. The method according to claim 5 or 10, characterized in that: in, The preset value is determined according to the molar ratio f of the iron element in the iron and manganese elements in the positive electrode active material.

15. The method according to claim 14, characterized in that The preset value includes fS, where S is the SOC value of the secondary battery when it is fully charged.

16. The method according to any one of claims 1 to 2, characterized in that: The preset battery temperature includes any temperature in a preset temperature range, wherein the preset temperature range is any temperature range of 30°C to 90°C, 30°C to 80°C, 30 to 50°C, 30 to 40°C, 50 to 80°C, 40°C to 50°C, and 40°C to 45°C.

17. A charging device, characterized in that: The device comprises: a charging module and a maintaining module; The charging module is used to charge the secondary battery; The maintaining module is used to maintain the battery temperature of the secondary battery greater than or equal to a preset battery temperature during the process of charging the secondary battery; The positive electrode active material of the secondary battery includes LiMPO4, wherein M includes Mn and Fe elements.

18. A battery pack, characterized in that: include: A secondary battery, wherein the positive electrode active material of the secondary battery comprises LiMPO4, wherein M comprises Mn and Fe elements; The temperature regulating mechanism is used to maintain the battery temperature of the secondary battery greater than or equal to a preset battery temperature.

19. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the method according to any one of claims 1 to 16 is implemented.

20. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 16 is implemented.

Images