Charging method and device, electronic device and readable storage medium

Abstract

The present application provides a charging method and device, an electronic device and a readable storage medium, the charging method comprising: collecting the state and / or cumulative state information of the battery during the step-by-step constant voltage charging process; determining the first charging cut-off condition of the current step and the target charging voltage of the next step according to the state and / or cumulative state information; wherein the step-by-step constant voltage charging comprises at least two consecutive constant voltage charging steps; and charging the battery for the next step when the state information and / or cumulative state information meets the corresponding first charging cut-off condition. The charging method provided by the present application adjusts the charging voltage and cut-off condition of each charging step according to the real-time state of the battery in each step of the constant voltage charging, thereby avoiding the problem of mismatch between the charging parameters and the actual state of the battery caused by the inaccurate estimated aging state, and can improve the charging speed and reduce safety risks.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and more specifically, to a charging method and device, an electronic device, and a readable storage medium. Background Art

[0002] New energy batteries are increasingly being used in life and industry. For example, new energy vehicles equipped with batteries have been widely used; in addition, batteries are increasingly being used in energy storage and other fields. In related technologies, battery charging methods include constant current (CC) charging, constant voltage (CV) charging, constant current and constant voltage combined charging, and step-by-step constant voltage charging.

[0003] The step-by-step constant voltage charging method includes multiple charging steps. In each charging step, different voltages are used to charge the battery. After the step cut-off condition is reached, the next charging step is entered. This charging method can improve charging speed and safety.

[0004] However, in the existing step-by-step constant-voltage charging, the charging voltage and step cutoff condition of each charging step depend on the accuracy of the charging model's description of the battery's physical characteristics. Its charging parameters are strongly correlated with the battery's state of charge (SOC). When there is an error in the SOC estimation, the charging time will be extended or the allowable charging rate will be exceeded.

[0005] The battery charging capacity changes during the production or aging process. The existing charging parameters are determined based on the estimated battery aging state. Since the estimated aging state is inaccurate, the charging current will not match the actual state of the battery. For example, the charging capacity of some batteries is not fully utilized, while the charging current of some batteries exceeds their charging capacity, which poses a charging safety risk. Summary of the invention

[0006] The present application provides a charging method and device, an electronic device and a readable storage medium. The technical solution adopted in the present application is as follows:

[0007] In a first aspect, a charging method is provided, the method comprising: in a process of performing step-by-step constant voltage charging on a battery, collecting state information of the battery in a current step and / or accumulated state information in the current step; the step-by-step constant voltage charging comprises at least two consecutive constant voltage charging steps; according to the state information and / or accumulated state information, querying a preset charging step table to determine a first charging cutoff condition of the current step and a target charging voltage of the next step; wherein the preset charging step table comprises a mapping relationship between different state information and / or accumulated state information and different first charging cutoff conditions and target charging voltages; the first charging cutoff condition is set to: before reaching the first charging cutoff condition, the charging current of the battery is less than or equal to the charging capacity of the battery; the target charging voltage is configured to: when charging the battery at the target charging voltage, the charging current of the battery is less than or equal to the charging capacity of the battery; the charging capacity of the battery is related to at least one of the state of charge, cell system, impedance, polarization voltage and open circuit voltage of the battery; when the state information and / or accumulated state information meets the corresponding first charging cutoff condition, charging the battery for the next step based on the target charging voltage.

[0008] According to the above technical means, when the battery is charged with constant voltage in steps, the battery status information and cumulative status information are collected in real time in each constant voltage charging step, and the charging voltage and cutoff conditions of each charging step in the step constant voltage charging are adjusted according to the real-time status of the battery, thereby avoiding the problem of mismatch between the preset charging parameters and the actual state of the battery caused by inaccurate estimated aging status, which can improve the charging speed and reduce safety risks.

[0009] In some embodiments, before performing step-by-step constant-voltage charging on the battery, the method also includes: detecting a charging parameter of the battery during charging the battery using a first charging method, wherein the first charging method is different from the step-by-step constant-voltage charging; determining that the battery has reached a polarization stable state when the charging parameter of the battery meets a preset condition; and performing step-by-step constant-voltage charging on the battery when the battery has reached a polarization stable state.

[0010] According to the above technical means, before the battery is charged with step constant voltage, the battery is first charged to a polarization stable state using other charging methods, which can avoid the influence of different battery polarization characteristics on the charging speed during step constant voltage charging.

[0011] In some embodiments, the charging parameters include at least one of the following: a first duration of the first charging mode, a state of charge (SOC) of the battery, an SOC increment of the battery within the first duration, an increment of the battery capacity within the first duration, a temperature change of the battery within the first duration, a voltage of the battery within a preset time interval, and a voltage change of the battery within a preset time interval; the charging parameters meet preset conditions, including at least one of the following: the first duration is greater than or equal to a first time threshold; the SOC is greater than or equal to a first SOC threshold; the SOC increment is greater than or equal to a first SOC increment threshold; the battery capacity increment is greater than or equal to a first battery capacity increment threshold; the temperature change is greater than or equal to a first battery temperature rise threshold; the battery voltage within a preset time interval is less than or equal to a first voltage threshold; the voltage change of the battery within a preset time interval is less than a first voltage change threshold.

[0012] According to the above technical means, when the battery is charged using the first charging method, whether the battery has reached a polarization stable state is judged based on whether the charging parameters in multiple dimensions meet the preset conditions, which increases the accuracy of the judgment and enables the charging process to be switched to step-by-step constant voltage charging in a timely manner to increase the charging speed of the battery.

[0013] In some embodiments, before charging the battery using the first charging method, the charging method also includes: charging the battery using the second charging method, and when the second switching condition is met, charging the battery using the first charging method; wherein the first charging method and the second charging method are different; the second charging method is any one of constant current charging, constant current and constant voltage combination charging, pulse charging, constant voltage charging, and segmented constant voltage charging; the first charging method is any one of constant current charging, constant current and constant voltage combination charging, pulse charging, and constant voltage charging.

[0014] According to the above technical means, before the step-by-step constant voltage charging, the battery is charged successively using the second charging method and the first charging method, which can speed up the time for the battery to reach a polarization stable state and improve the charging efficiency.

[0015] In some embodiments, the charging method further includes: when the current step is the first charging step of the step constant voltage charging, querying the charging step table according to the battery status information at the initial moment of the step constant voltage charging to determine the charging voltage of the current step.

[0016] According to the above technical means, by querying the preset charging step table based on the battery status information to determine the charging voltage when the battery just enters the step constant voltage charging, the start time of the step constant voltage charging can be shortened; based on the preset charging step table, the accuracy of the charging control can be improved, making the charging process more efficient and safe.

[0017] In some embodiments, the status information includes at least one of the following: the charging current of the battery, the charging rate of the battery, the temperature of the battery, and the state of charge of the battery; the cumulative status information includes at least one of the following: the charging time, charging power, charging energy, cumulative temperature rise, and voltage change value of the battery in the current step.

[0018] According to the above technical means, the battery's state information and cumulative state information in multiple dimensions are used to accurately describe the battery's state, and the charging strategy of step constant voltage charging is determined accordingly, so that the charging parameters used in the charging process match the actual situation of the battery, which can give full play to the battery's charging capacity and improve the charging speed.

[0019] In some embodiments, the battery includes one battery cell, and the temperature of the battery is the temperature of the one battery cell; or, the battery includes multiple battery cells, and the temperature of the battery is the maximum value, minimum value, or average value of the temperatures of the multiple battery cells.

[0020] According to the above technical means, when the battery has multiple cells, the maximum, minimum or average temperature of the multiple cells is used to describe the overall temperature of the battery, and the step charging strategy is determined based on the temperature to avoid adverse effects on the selection of the charging strategy when the temperature difference between the multiple cells is large.

[0021] In some embodiments, the first charging cutoff condition is that the charging current of the current step reaches a preset current threshold, and the preset current threshold is greater than or equal to the charging capacity of the battery; or, the first charging cutoff condition is that the charging time of the current step reaches a preset charging time, and the preset charging time is set to when the preset charging time is reached, the charging current of the battery is less than or equal to the charging capacity of the battery.

[0022] According to the above technical means, during the charging process, the charging current of each step is limited to below the charging capacity of the battery, which can ensure charging safety.

[0023] In a second aspect, a charging device is provided, comprising: a collecting unit, used to collect the state information of the battery in the current step and / or the accumulated state information in the current step during the process of performing step-by-step constant voltage charging on the battery; the step-by-step constant voltage charging includes at least two consecutive constant voltage charging steps; a first determining unit, used to query a preset charging step table according to the state information and / or the accumulated state information, and determine the first charging cutoff condition of the current step and the target charging voltage of the next step; wherein the preset charging step table includes a mapping relationship between different state information and / or accumulated state information and different first charging cutoff conditions and target charging voltages; the first charging cutoff condition is set to: before reaching the first charging cutoff condition, the charging current of the battery is less than or equal to the charging capacity of the battery; the target charging voltage is configured to: when charging the battery with the target charging voltage, the charging current of the battery is less than or equal to the charging capacity of the battery; the charging capacity of the battery is related to at least one of the state of charge, cell system, impedance, polarization voltage and open circuit voltage of the battery; and a charging unit, used to charge the battery for the next step based on the target charging voltage when the state information and / or the accumulated state information meets the corresponding first charging cutoff condition.

[0024] In a third aspect, an electronic device is provided, comprising a battery, a memory and a processor, wherein the memory is used to store a computer program, and when the battery is charged, the computer program is executed by the processor to implement the method described in the first aspect.

[0025] According to a fourth aspect, a computer-readable storage medium is provided for storing a computer program, wherein the computer program implements the method described in the first aspect when executed. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic flow chart of a charging method provided in one embodiment of the present application;

[0027] Figure 2 A schematic diagram showing the charging capacity of the battery and the charging current during constant voltage charging as the SOC changes;

[0028] Figure 3 A schematic flow chart of a charging method provided in another embodiment of the present application;

[0029] Figure 4 A schematic flow chart of a charging method provided in yet another embodiment of the present application;

[0030] Figure 5 A schematic flow chart of a charging method provided in yet another embodiment of the present application;

[0031] Figure 6 A schematic structural diagram of a charging device provided in an embodiment of the present application;

[0032] Figure 7 A schematic structural diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the specific technical solution of the present application will be further described in detail below in conjunction with the drawings in the embodiments of the present application. The following embodiments are used to illustrate the present application, but are not used to limit the scope of the present application.

[0034] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used in this application are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0035] In the following description, reference is made to “some embodiments”, “this embodiment”, “embodiments of the present application” and examples, etc., which describe a subset of all possible embodiments, but it can be understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0036] In the following description, the terms "first / second / third" involved are merely used to distinguish similar objects and do not represent a specific ordering of the objects. It can be understood that "first / second / third" can be interchanged with a specific order or sequence where permitted, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.

[0037] At present, new energy batteries are more and more widely used in life and industry. New energy batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric vehicles, and aerospace and other fields. With the continuous expansion of the application field of power batteries, the market demand is also constantly expanding. In the embodiment of the present application, the battery involved may be a battery cell, also known as a battery cell. A battery cell refers to a basic unit that can realize the mutual conversion of chemical energy and electrical energy, which can be used to make a battery module or a battery pack, so as to supply power to an electrical device. A battery cell may be a secondary battery, which refers to a battery cell that can be used to activate the active material by charging after the battery cell is discharged. The battery cell may be a lithium ion battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel hydrogen battery, a nickel cadmium battery, a lead-acid battery, etc., and the embodiment of the present application is not limited to this.

[0038] In the embodiments of the present application, the battery cell is the core component of the battery pack. A battery pack usually contains multiple battery cells, which are combined together to provide the required power capacity and voltage. The components of the battery pack include at least: battery cells, battery management system (BMS), housing, connecting harness, connector and interface, etc. These components work together to combine the battery cells into a fully functional battery pack for various application scenarios. For example, the battery pack can be applied to electric vehicles, energy storage systems, portable electrical equipment, solar energy systems, wind energy systems, emergency backup power supplies, power tools or electric bicycles, etc. The embodiments of the present application do not make any restrictions on this, and can be selected according to the actual application scenario.

[0039] In the embodiments of the present application, the battery cell may refer to a battery cell of any shape, such as a square battery cell, a round battery cell, etc. And the battery cell usually refers to a battery cell, which is one of the basic units that constitute a battery. The battery cell is the core component of the battery and is responsible for storing and releasing electrical energy. The battery cell may be: a lithium-ion battery cell (Li-ion cell), a lithium polymer battery cell (Li-polymer cell), a nickel-metal hydride battery cell (NiMH cell), etc. The embodiments of the present application do not impose any restrictions on the type of battery cell, and the specific type can be selected according to the actual application scenario.

[0040] It should be noted that the battery pack can use different types of battery cells, such as lithium-ion batteries, nickel-metal hydride batteries, and lithium polymer batteries, etc., depending on the needs and performance requirements of the actual application.

[0041] In the embodiment of the present application, the battery may also be a single physical module including one or more battery cells to provide higher voltage and capacity. When there are multiple battery cells, the multiple battery cells are connected in series, in parallel or in hybrid connection through a busbar component.

[0042] For batteries, a suitable charging method can not only improve the battery's charging performance and increase the battery's service life, but also improve the safety of battery use. In the process of large-scale promotion and application of batteries, the research on the optimal charging strategy has received more and more attention.

[0043] There are many different charging methods available, and the most commonly used methods include constant current (CC) charging, constant voltage (CV) charging, and constant current and constant voltage combined charging. The charging strategies of the above charging methods depend on the accuracy of the charging model's description of the battery's physical characteristics. The charging time is strongly related to the battery's state of charge (SOC). When there is an error in the SOC estimation, the charging time will be extended or exceed the allowed charging rate. This problem is particularly evident in fast charging products.

[0044] In addition, the battery charging capacity changes during the production or aging process. The charging current threshold in the existing multi-stage constant current charging strategy is determined based on the estimated battery aging state. Since the estimated aging state is inaccurate, the charging current will not match the actual state of the battery. For example, the charging capacity of some batteries is not fully utilized, while the charging current of some batteries exceeds their charging capacity, which poses a charging safety risk.

[0045] In view of the above problems, the embodiments of the present application provide a charging method and device, an electronic device and a readable storage medium. The technical solutions provided by the embodiments of the present application will be described in detail below in conjunction with the accompanying drawings.

[0046] Figure 1 A schematic flow chart of a charging method provided in an embodiment of the present application, the method is used to charge a battery, and the battery can be any of the batteries described above, such as a lithium-ion battery, a sodium-ion battery, a sodium-lithium-ion battery, a lithium metal battery, a sodium metal battery, a lithium-sulfur battery, a magnesium-ion battery, a nickel-hydrogen battery, a nickel-cadmium battery, a lead-acid battery, etc.

[0047] Figure 1 The charging method includes steps S110-S130.

[0048] In step S110, during the process of performing step-by-step constant voltage charging on the battery, state information of the battery at the current step and / or accumulated state information at the current step are collected.

[0049] Step-by-step constant voltage charging can also be called segmented constant voltage charging. Its charging process includes at least two constant voltage charging steps. In each charging step, the charging voltage remains constant, and the charging voltages of two adjacent charging steps are different.

[0050] The embodiment of the present application does not limit the change trend of the charging voltage of two adjacent charging steps. The two adjacent charging steps include a first charging step and a second charging step. The voltage of the first charging step may be greater than the charging voltage of the second charging step, or the charging voltage of the first charging step may be less than the charging voltage of the second charging step.

[0051] In the embodiment of the present application, there is no limitation on the changing trend of the charging voltage in the continuous multiple steps. For example, the charging voltage in the continuous multiple charging steps may be successively reduced or increased; or, the magnitude of the charging voltage in the continuous multiple charging steps may be first reduced and then increased, or first increased and then reduced. The method for determining the charging voltage of each charging step will be described in more detail later.

[0052] The current step described in the above step S110 may be any charging step except the last charging step among the multiple charging steps of the step-by-step constant voltage charging, which is not limited in the embodiment of the present application.

[0053] The battery status information in the embodiment of the present application is used to characterize the status of the battery at the current moment. The status information may include, for example, the current charging current, the battery charging rate, the battery temperature, and the battery state of charge.

[0054] The status information of the above-mentioned various batteries can be collected through a battery management system (BMS) in the battery.

[0055] In some embodiments, for the battery temperature mentioned above, when the battery is a single-cell battery, the battery temperature is the temperature of the cell; when the battery includes multiple cells, the battery temperature may be the maximum, minimum or average value of the temperatures of the multiple cells.

[0056] According to the above technical means, when the battery has multiple cells, the maximum, minimum or average temperature of the multiple cells is used to describe the overall temperature of the battery, and the step charging strategy is determined based on the temperature to avoid adverse effects on the selection of the charging strategy when the temperature difference between the multiple cells is large.

[0057] In the battery using the charging method of the embodiment of the present application, each battery cell is configured with a thermistor, which can be a positive temperature coefficient thermistor (PTC thermistor) and a negative temperature coefficient thermistor (NTC thermistor), which is connected to the BMS to collect the temperature of each battery cell and send the collected temperature information to the BMS.

[0058] The accumulated status information of the battery in the embodiment of the present application refers to the accumulated value of some relevant status information of the battery from the initial moment of the current step to the current time.

[0059] The accumulated status information in the embodiment of the present application may include: the charging time, charging power, charging energy, accumulated temperature rise and voltage change value of the battery in the current step. The collection of the various accumulated status information can also be performed by the BMS in the battery.

[0060] Among them, charge capacity is the product of current and time, and the unit is Ah; charge energy is the product of voltage, current and time, and the unit is Wh.

[0061] In step S120, according to the state information and / or the accumulated state information, a preset charging step table is queried to determine the first charging cut-off condition of the current step and the target charging voltage of the next step.

[0062] The preset charging step table includes the relationship between different state information and / or accumulated state information and different first charging cut-off conditions and target charging voltages.

[0063] As mentioned above, the battery status information and the accumulated status information respectively include information of multiple dimensions, and the charging step table can be a mapping relationship between any one or more different information in the multiple status information and the first charging cut-off condition and the target charging voltage. In other words, the first charging cut-off condition and the target charging voltage can be determined based on one or more of the battery status information.

[0064] For example, the charging step table may be a one-dimensional mapping relationship between the battery's charging rate or battery temperature and the first charging cutoff condition and the target charging voltage; or, the charging step table may also be a two-dimensional mapping relationship between the battery's charging current and temperature and the first charging cutoff condition and the target charging voltage; or, the charging step table may also be a multi-dimensional mapping relationship between any one or more of the battery's multiple state information and the first charging cutoff condition and the target charging voltage; or, the charging step table may be a mapping relationship between any one or more of the multiple accumulated state information and the first charging cutoff condition and the target charging voltage. In other words, the first charging cutoff condition and the target charging voltage may also be determined based on one or more of the accumulated state information of the battery.

[0065] Alternatively, the charging step table may be a mapping relationship between any one or more of the multiple state information and any one or more of the multiple accumulated state information and the first charging cutoff condition and the target charging voltage. In other words, the first charging cutoff condition and the target charging voltage may be determined in combination with the state information and the accumulated state information of the battery.

[0066] According to the above technical means, the battery's state information and cumulative state information in multiple dimensions are used to accurately describe the battery's state, and the charging strategy of step constant voltage charging is determined accordingly, so that the charging parameters used in the charging process match the actual situation of the battery, which can give full play to the battery's charging capacity and improve the charging speed.

[0067] In an embodiment of the present application, the first charging cut-off condition is set as: before the first charging cut-off condition is reached, the charging current of the battery is less than or equal to the charging capacity of the battery; the target charging voltage is configured as: when the battery is charged with the target charging voltage, the charging current of the battery is less than or equal to the charging capacity of the battery.

[0068] The charging capability of a battery is related to at least one of the state of charge, cell system, impedance, polarization voltage and open circuit voltage of the battery.

[0069] At each step, the design principle of the battery charging voltage is to maximize the battery's charging capacity. The battery voltage is the sum of the open circuit voltage and the polarization voltage. The polarization voltage is positively correlated with the battery impedance and the battery charging capacity. For batteries of different systems, the change trend of the open circuit voltage is different; for example, the open circuit voltage of the ternary battery cell gradually increases with the increase of SOC, and the open circuit voltage of the iron-lithium battery cell has two platform areas; the battery cell impedance and charging capacity may be different at the same SOC. Therefore, the change trend of the sum of the battery cell open circuit voltage and polarization voltage is not fixed. Each step of the step-by-step constant voltage charging needs to give full play to the battery's charging capacity. In other words, the charging voltage of each step needs to be determined according to the current state of the battery, rather than changing according to a preset rule.

[0070] In some embodiments, the first charging cut-off condition is that the charging current of the current step reaches a preset current threshold, and the preset current threshold is greater than or equal to the charging capacity of the battery.

[0071] Figure 2 The diagram is a schematic diagram showing the battery charging capacity and the charging current during constant voltage charging as the battery SOC changes. The intersection of the battery charging capacity 210 and the constant voltage charging current 220 is the current threshold. If the cutoff condition of the current step is less than the current threshold, the current of the constant voltage charging will be greater than the charging capacity of the battery cell, which poses a safety risk. Therefore, the current threshold is set to be greater than or equal to the battery charging capacity.

[0072] In some embodiments, the first charging cut-off condition is that the charging time of the current step reaches a preset charging time, and the preset charging time is set to: when the charging time of the battery reaches the preset charging time, the charging current of the battery is less than or equal to the charging capacity of the battery.

[0073] According to the above technical means, during the charging process, the charging current of each step is limited to below the charging capacity of the battery, which can ensure charging safety.

[0074] The above method is described in more detail below with two examples. Table 1 below shows an example of a charging step table when the first charging cutoff condition is the charging rate. Taking the first step as an example, the charging voltage of this step is 3.31V. When the charging rate reaches 4C, the cutoff condition is met, and the second charging step is entered, and charging is performed at a charging voltage of 3.524V. When the charging rate reaches 4C again, the third charging step is performed. In each subsequent charging step, the charging voltage of the next charging step and the cutoff condition of the current step are determined based on the parameters in Table 1, until the cutoff condition of the tenth charging step is reached to complete the step-by-step constant voltage charging process.

[0075] Table 1

[0076]

[0077] Table 2 below shows an example of a charging step table when the charging voltage and the cut-off condition are determined based on the temperature information of the battery. As shown in Table 2, different combinations of charging voltages and cut-off conditions correspond to different temperatures. For example, when the battery temperature is 60°C, the charging voltage in the first charging step is 3.229V, and the cut-off condition of this step is that the charging rate reaches 3.5C; when the charging rate reaches 3.5C, the cut-off condition is met, and the second charging step is entered, and charging is performed at a charging voltage of 3.339V. When the charging rate reaches 3C, the third charging step is performed. In each subsequent charging step, the charging voltage of the next charging step and the cut-off condition of the current step are determined based on the parameters in Table 2, until the cut-off condition of the tenth charging step is reached to complete the step-by-step constant voltage charging process.

[0078] Table 2

[0079]

[0080] Continue reading Figure 1 In step S130, when the state information and / or the accumulated state information meets the corresponding first charging cut-off condition, the battery is charged for the next time based on the target charging voltage.

[0081] After determining the first charging cutoff condition of the current step and the target charging voltage of the next step using the charging step table based on the status information and / or the accumulated status information, the battery status is monitored. When the first charging cutoff condition is met, the charging of the current step is terminated and the next charging step is entered.

[0082] According to the above technical solution provided in the embodiment itself, when the battery is charged with constant voltage in steps, the battery status information and cumulative status information are collected in real time in each constant voltage charging step, and the charging voltage and cutoff condition of each charging step in the step constant voltage charging are adjusted according to the real-time status of the battery, thereby avoiding the problem of mismatch between the preset charging parameters and the actual status of the battery caused by inaccurate estimated aging status, which can improve the charging speed and reduce safety risks.

[0083] The above-mentioned step-by-step constant voltage charging method can increase the charging speed of the battery and improve the safety of battery charging. However, some characteristics of the battery cells will lead to an extension of the constant voltage charging time, which is specifically manifested in the different DC internal resistance of the battery cells, including different DC internal resistance of the battery at different charging stages, differences in DC internal resistance of batteries from different batches, and changes in DC internal resistance of the battery during aging. Using the same voltage for step-by-step constant voltage charging will lead to extended steps or skipped steps, which will in turn cause problems such as extended charging time.

[0084] In view of the above problems, in some embodiments, Figure 3 As shown, before performing step-by-step constant voltage charging on the battery, the charging method provided in the embodiment of the present application further includes steps S310-S330.

[0085] In step S310, in the process of charging the battery based on the first charging method, the charging parameters of the battery are detected.

[0086] The first charging method is different from the aforementioned step-by-step constant voltage charging. The first charging method may be, for example, any one of constant current charging, constant current and constant voltage combined charging, pulse charging, and constant voltage charging.

[0087] Step S320: When the charging parameters of the battery meet preset conditions, it is determined that the battery reaches a polarization stable state.

[0088] There are many ways to determine whether a battery has reached a stable polarization state. When a battery is charged in a first charging mode for a certain period of time or reaches a certain SOC, it can be considered that it has reached a stable polarization state; or, it can be determined based on the size of the battery voltage whether it has reached a stable polarization state; or, it can be determined based on whether a combination of multiple parameters meets preset conditions whether the battery has reached a stable polarization state. For example, when the battery temperature is greater than a preset threshold and the SOC is greater than a preset SOC threshold, when the difference between the actual cell voltage and the voltage calibration value is greater than 2mV, it is determined that the battery has reached a stable polarization state.

[0089] It should be noted that the above-listed methods of determining that the battery reaches a stable polarization state according to the charging parameters are only examples. In some embodiments of the present application, the charging parameters of the battery include at least one of the following: the first duration of the first charging method, the state of charge SOC of the battery, the SOC increment of the battery within the first duration, the increment of the battery capacity within the first duration, the temperature change of the battery within the first duration, the voltage of the battery within a preset time interval, and the voltage change of the battery within the preset time interval. The charging parameters satisfying the preset conditions may include at least one of the following: the first duration is greater than or equal to the first time threshold; the SOC is greater than or equal to the first SOC threshold; the increment of the SOC is greater than or equal to the first SOC increment threshold; the increment of the battery capacity is greater than or equal to the first battery capacity increment threshold; the temperature change is greater than or equal to the first battery temperature rise threshold; the voltage of the battery within the preset time interval is less than or equal to the first voltage threshold; the voltage change of the battery within the preset time interval is less than the first voltage change threshold.

[0090] According to the above technical means, when the battery is charged using the first charging method, whether the battery has reached a polarization stable state is judged based on whether the charging parameters in multiple dimensions meet the preset conditions, which increases the accuracy of the judgment and enables the charging process to be switched to step-by-step constant voltage charging in a timely manner to increase the charging speed of the battery.

[0091] In some embodiments, the "voltage of the battery within a preset time interval" and the "voltage change of the battery within a preset time interval" in the above-mentioned multiple charging parameters can be determined by a current heuristic method. For example, a pulse current can be used to charge the battery, and the voltage within a preset time interval under the pulse current is measured. When the voltage is less than or equal to a first voltage threshold or the voltage change within the time interval is less than the first voltage change threshold, it is determined that the battery has reached a polarization stable state.

[0092] In step S330, when the battery reaches a polarization stable state, the battery is charged at a step-by-step constant voltage.

[0093] According to the above technical means, before the battery is charged with step constant voltage, the battery is first charged to a polarization stable state using other charging methods, which can avoid the influence of different battery polarization characteristics on the charging speed during step constant voltage charging.

[0094] In some embodiments, before charging the battery using the first charging method, the charging method further includes: charging the battery using the second charging method, and when the second switching condition is met, charging the battery using the first charging method.

[0095] The second charging method is different from the first charging method, and the second charging method can be any one of constant current charging, constant current and constant voltage combination charging, pulse charging, constant voltage charging, and segmented constant voltage charging.

[0096] According to the above technical means, before the step-by-step constant voltage charging, the battery is charged successively using the second charging method and the first charging method, which can speed up the time for the battery to reach a polarization stable state and improve the charging efficiency.

[0097] In some embodiments, the charging method further includes: when the current step is the first charging step of the step constant voltage charging, querying the charging step table according to the battery status information at the initial moment of the step constant voltage charging to determine the charging voltage of the current step.

[0098] The charging step table can refer to Table 1 and Table 2 above. Taking the charging step table shown in Table 2 as an example, the charging voltage of the first step can be determined according to the battery temperature in the battery status information. For example, when the temperature is 25° C., the charging voltage is 3.31V.

[0099] According to the above technical means, by querying the preset charging step table based on the battery status information to determine the charging voltage when the battery just enters the step constant voltage charging, the start time of the step constant voltage charging can be shortened; based on the preset charging step table, the accuracy of the charging control can be improved, making the charging process more efficient and safe.

[0100] One aspect of the charging method provided in the embodiments of the present application is to solve the following technical problems existing in the constant voltage charging method in the related art:

[0101] Related technology discloses a constant voltage charging method for 12V lithium-ion batteries, which first uses constant current charging to a first predetermined voltage, and then uses V2, V3, V4... Vn for constant voltage charging until the voltage Vn charging current decreases to 0.05C and the charging current is cut off, wherein the constant voltage charging voltage increases by 0.1V each time on the basis of V1 until the voltage Vn = 14.6V. Without raising the matching standard, the problem of overcurrent and overvoltage in constant voltage charging of 12V lithium-ion batteries on the whole vehicle is solved, and the matching rate of the whole package is improved.

[0102] The technical solution disclosed in the above-mentioned related art is limited to 12V lithium batteries, and its charging method is a combination of constant current and constant voltage charging methods, in which the charging voltage in the constant voltage charging process is a gradually increasing relationship, which limits the changing trend of the charging voltage in the charging process. In addition, the technical solution only states that the charging current Vn is cut off when it decreases to 0.05C, and does not specify the charging cut-off conditions for other steps.

[0103] Traditional charging methods without models are generally based on a preset charging table. Model-based charging strategies depend on the accuracy of the charging model's description of the battery's physical characteristics, and the charging time is strongly related to the battery's SOC. Especially when there is an error in the SOC estimation, the charging time will be extended or the allowed charging rate will be exceeded. In addition, the battery's charging capacity changes during the production or aging process. If the existing step-charging strategy uses the same charging current threshold, it may cause some batteries to not be fully charged, or it may cause the charging current to exceed the battery's charging capacity, posing a charging safety risk.

[0104] The step-by-step constant voltage charging method provided in the embodiment of the present application can improve charging speed or safety. In each charging step, the step cut-off condition is determined according to the battery status information collected by the BMS, or the cumulative charging information status of the step reaches a set threshold, or the above conditions are combined.

[0105] Among them, the battery status information collected by BMS includes: charging current, charging rate, battery temperature and battery charge state, etc. The cumulative status information of each charging step includes: charging time, charging power, charging energy, cumulative charging temperature rise, voltage change value of this step, etc.

[0106] The threshold value may be set to a fixed threshold value or to determine the threshold value based on the relationship between the above state parameter and the threshold value. The above condition combination may include: using the above BMS to collect battery state information and multiple combinations of the accumulated state information of the charging step. For example, the charging current reaches the threshold value and the charging power reaches the threshold value.

[0107] In the technical solution provided in the embodiment of the present application, the number of steps of the step-by-step constant-voltage charging is ≥ 2. If the voltage change of the step-by-step constant-voltage charging is greater and the number of steps is greater, the charging capacity of the battery cell can be maximized.

[0108] Taking the cut-off condition as the charging current as an example, the current threshold of each step is related to the charging capacity of the battery. During constant voltage charging, the charging current does not exceed the charging capacity of the battery cell, so the current threshold is greater than or equal to the charging capacity of the battery. Figure 2 For example, two curves 210 and 220 represent the battery charging capacity and constant voltage charging current respectively. If the step cut-off condition is less than the current threshold, the constant voltage charging current will be greater than the battery charging capacity, which poses a safety risk. Therefore, the current threshold must be greater than or equal to the battery charging capacity.

[0109] When the step cut-off condition is the charging time, the constant voltage charging current in this step cannot be greater than the charging capacity of the battery.

[0110] The technical solution of the present application can improve the charging speed. The current changes smoothly during the charging process, which is more in line with the charging capacity of the battery, which is conducive to improving the charging speed.

[0111] At the same time, the existing step charging strategy uses a fixed current during the charging process. If the rate is too high (exceeding the actual battery charging capacity), it may cause the charging voltage to be too high or the anode potential to be too low, or even exceed the battery's optimal charging voltage boundary, posing a safety risk. If the rate is too low, it will affect the charging speed. The current of constant voltage charging will be adaptively adjusted according to the battery impedance or state of charge, which can improve charging safety and speed. For example, when the battery impedance increases after aging, the battery cell current is reduced when charging with the same voltage, which matches the actual reduced charging capacity of the aging battery cell.

[0112] The present application embodiment provides a step-by-step constant voltage charging method, such as Figure 4 As shown, the step-by-step constant voltage charging method includes:

[0113] Step S410, detecting whether the battery is in a charging state, if so, proceeding to step S420 to perform step-by-step constant voltage charging, otherwise proceeding to step S430 to end charging.

[0114] Step S420, step-by-step constant voltage charging, includes step S421 and step S422.

[0115] In step S421, the initial step of constant voltage charging is determined according to the mapping gap between the temperature, state of charge, battery voltage and other information collected by the BMS at the initial moment of charging and the charging step.

[0116] For example, the charging step table corresponding to the minimum temperature, maximum temperature and SOC collected by the BMS is queried to obtain the initial step value. The charging step table can be a one-dimensional array related to SOC, a two-dimensional array consisting of temperature and SOC, or a three-dimensional array consisting of temperature, SOC and SOH.

[0117] Examples of charging step tables can be found in Table 1 and Table 2 above, which will not be described in detail here.

[0118] In step S422, if the current constant voltage step charging reaches the above step termination condition, the charging is switched to the next step.

[0119] In step S430, if it is detected that the battery is in a fully charged state or the gun is unplugged, charging is stopped.

[0120] Another aspect of the technical solution provided in the embodiments of the present application is to solve the problem that due to the different DC internal resistance DCR of the battery cells at different charging stages, the difference in DCR of different batches of battery cells, and the change in DCR during the aging process of the battery cells, the DCR of the battery cells has significant differences, and the charging current is different when the same voltage is used for constant voltage charging, resulting in extended steps or skipped steps, thereby causing the charging time to be extended.

[0121] This technical solution uses a combination of multiple charging methods to charge the battery during the charging process, that is, before the segmented constant voltage charging, other charging methods are used to charge the battery to a stable polarization state to avoid the influence of different polarization internal resistance on the constant voltage charging process. Figure 5 As shown, the charging method includes the following steps:

[0122] Step S510, charging status detection, detects whether the battery cell / module / Pack / entire vehicle is in a charging state. If so, proceed to step 520 to perform charging in a variety of combined charging methods. Otherwise, proceed to step 530 to end charging.

[0123] Step 520 further includes steps S521-S523.

[0124] In step S521, the battery is charged using a first charging method, which may be constant current charging, pulse charging, constant power charging, or a combination of the above.

[0125] In step S522, determine whether the switching condition for step constant voltage charging is met, if so, go to step S523, otherwise go to step S521.

[0126] In step S523, the battery is charged using a step-by-step constant voltage charging method.

[0127] The above switching conditions include duration T, BMS estimated SOC, charging time and charged SOC / capacity / temperature rise or charging voltage or other dynamic adaptive judgment algorithms.

[0128] If the preset condition is duration T, when the charging mode switching condition is time, first use the first charging mode to charge for 1 minute (TBD), and then use the step-by-step constant voltage charging mode to charge.

[0129] If the charging method is a dynamic adaptive judgment algorithm method, such as the current trial method, a specified pulse current is used for charging. According to the voltage within the time interval threshold (1s-10s, TBD) under the current, if the voltage is less than or equal to the specified threshold, or the voltage change is less than the specified threshold, it is judged that the charging has reached a stable state and enters the step-by-step constant voltage charging mode. Otherwise, the constant current step charging mode is used.

[0130] Step 530: If it is detected that the battery cell / module / Pack / entire vehicle is in a fully charged state or the gun is unplugged, then charging is stopped.

[0131] Combination of the above Figures 1 to 5 , the method embodiment of the present application is described in detail, and the following will be combined with Figure 6 and Figure 7, the device embodiment of the present application is described. It should be understood that the description of the device embodiment corresponds to the method embodiment, so the part not described in detail can refer to the method embodiment above.

[0132] Figure 6 A schematic structural diagram of a charging device provided in an embodiment of the present application, the charging device 600 includes:

[0133] The collecting unit 610 is used to collect the state information of the battery in the current step and / or the accumulated state information in the current step during the process of performing step-by-step constant voltage charging on the battery.

[0134] The first determination unit 620 is used to query a preset charging step table according to the state information and / or the accumulated state information, and determine the first charging cut-off condition of the current step and the target charging voltage of the next step.

[0135] The preset charging step table includes mapping relationships between different state information and / or accumulated state information and different first charging cut-off conditions and target charging voltages.

[0136] The first charge cutoff condition is set as follows: before the first charge cutoff condition is reached, the charging current of the battery is less than or equal to the charging capacity of the battery.

[0137] The target charging voltage is configured such that when the battery is charged at the target charging voltage, the charging current of the battery is less than or equal to the charging capacity of the battery.

[0138] The charging capability of a battery is related to at least one of the state of charge, cell system, impedance, polarization voltage and open circuit voltage of the battery.

[0139] The charging unit 630 is configured to charge the battery for the next time based on the target charging voltage when the state information and / or the accumulated state information meets the corresponding first charging cut-off condition.

[0140] In some embodiments, the acquisition unit 610 is further configured to detect charging parameters of the battery during charging of the battery based on a first charging method, wherein the first charging method is different from step-by-step constant voltage charging.

[0141] The first determining unit 620 is further configured to determine that the battery reaches a polarization stable state when the charging parameters of the battery meet a preset condition.

[0142] The charging unit 630 is also used to perform step-by-step constant voltage charging on the battery when the battery reaches a polarization stable state.

[0143] In some embodiments, the charging parameters include at least one of the following: a first duration of the first charging mode, a state of charge (SOC) of the battery, an SOC increment of the battery within the first duration, an increment of the battery capacity within the first duration, a temperature change of the battery within the first duration, a voltage of the battery within a preset time interval, and a voltage change of the battery within a preset time interval.

[0144] The charging parameters meet preset conditions, including at least one of the following: the first duration is greater than or equal to the first time threshold; the SOC is greater than or equal to the first SOC threshold; the SOC increment is greater than or equal to the first SOC increment threshold; the battery capacity increment is greater than or equal to the first battery capacity increment threshold; the temperature change is greater than or equal to the first battery temperature rise threshold; the battery voltage within a preset time interval is less than or equal to the first voltage threshold; the battery voltage change within a preset time interval is less than the first voltage change threshold.

[0145] In some embodiments, the charging unit is further used to: charge the battery using the second charging method, and when the second switching condition is met, charge the battery using the first charging method.

[0146] Among them, the first charging method and the second charging method are different; the second charging method is any one of constant current charging, constant current and constant voltage combination charging, pulse charging, constant voltage charging and segmented constant voltage charging; the first charging method is any one of constant current charging, constant current and constant voltage combination charging, pulse charging and constant voltage charging.

[0147] In some embodiments, the first determination unit 620 is further used to: when the current step is the first charging step of the stepped constant voltage charging, query the charging step table according to the battery status information at the initial moment of the stepped constant voltage charging to determine the charging voltage of the current step.

[0148] In some embodiments, the status information includes at least one of the following: the charging current of the battery, the charging rate of the battery, the temperature of the battery, and the state of charge of the battery; the cumulative status information includes at least one of the following: the charging time, charging power, charging energy, cumulative temperature rise, and voltage change value of the battery in the current step.

[0149] In some embodiments, the battery includes one battery cell, and the temperature of the battery is the temperature of the one battery cell; or, the battery includes multiple battery cells, and the temperature of the battery is the maximum value, minimum value, or average value of the temperatures of the multiple battery cells.

[0150] In some embodiments, the first charging cutoff condition is that the charging current of the current step reaches a preset current threshold, and the preset current threshold is greater than or equal to the charging capacity of the battery; or, the first charging cutoff condition is that the charging time of the current step reaches a preset charging time, and the preset charging time is set to when the preset charging time is reached, the charging current of the battery is less than or equal to the charging capacity of the battery.

[0151] Figure 7 This is a schematic structural diagram of an electronic device provided in an embodiment of the present application. The electronic device 700 may be an electrical device such as a car. Figure 7 The electronic device 700 includes a battery 710, a memory 720 and a processor 730.

[0152] The battery 710 at least includes one or more battery cells, wherein the battery cells are used to provide the required power capacity and voltage.

[0153] The memory 720 is used to store a computer program. When charging the battery 710, the computer program is executed by the processor 730 to implement the charging method described in any of the above embodiments.

[0154] In the embodiment of the present application, the processor 720 may be at least one of an application-specific integrated circuit (ASIC), a digital signal processor (DSP), a digital signal processing device (DSPD), a programmable logic device (PLD), a field programmable gate array (FPGA), a central processing unit (CPU), a controller, a microcontroller, and a microprocessor. It is understandable that for different devices, the electronic device used to implement the above-mentioned processor function may also be other, and the embodiment of the present application does not specifically limit it.

[0155] In some embodiments, the processor 720 is a power management system BMS of the battery 710 .

[0156] The embodiment of the present application also provides a computer-readable storage medium on which a computer program is stored, and when the computer program is executed by a processor, some or all of the steps in the above method are implemented. The computer-readable storage medium can be transient or non-transient.

[0157] An embodiment of the present application also provides a computer program, including a computer-readable code. When the computer-readable code is run in a computing device, a processor in the computing device executes some or all of the steps for implementing the above method.

[0158] The present application also provides a computer program product, which includes a non-transitory computer-readable storage medium storing a computer program, and when the computer program is read and executed by a computer, some or all of the steps in the above method are implemented. The computer program product can be implemented in hardware, software, or a combination thereof.

[0159] In some embodiments, the computer program product is specifically embodied as a computer storage medium. In other embodiments, the computer program product is specifically embodied as a software product, such as a software development kit (SDK) and the like.

[0160] It should be noted that in the embodiments of the present application, if the above method is implemented in the form of a software function module and sold or used as an independent product, it can also be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the embodiment of the present application can be essentially or partly reflected in the form of a software product that contributes to the relevant technology. The software product is stored in a storage medium, including several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the methods of each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a U disk, a mobile hard disk, a read-only memory (ROM), a disk or an optical disk. In this way, the embodiments of the present application are not limited to any specific hardware, software or firmware, or any combination of hardware, software, and firmware.

[0161] It should be noted here that the description of the various embodiments above tends to emphasize the differences between the various embodiments, and the same or similar aspects can be referenced to each other. The description of the above device, storage medium, computer program and computer program product embodiments is similar to the description of the above method embodiment, and has similar beneficial effects as the method embodiment. For technical details not disclosed in the embodiments of the device, storage medium, computer program and computer program product of this application, please refer to the description of the method embodiment of this application for understanding.

[0162] It should be understood that "one embodiment" or "an embodiment" mentioned throughout the specification means that specific features, structures or characteristics related to the embodiment are included in at least one embodiment of the present application. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. In addition, these specific features, structures or characteristics can be combined in one or more embodiments in any suitable manner. It should be understood that in various embodiments of the present application, the size of the serial number of each step / process mentioned above does not mean the order of execution, and the execution order of each step / process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present application. The serial numbers of the embodiments of the present application mentioned above are for description only and do not represent the advantages and disadvantages of the embodiments.

[0163] It should be noted that, in the application, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "includes a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0164] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. The device embodiments described above are only schematic. For example, the division of units is only a logical function division. There may be other division methods in actual implementation, such as: multiple units or components can be combined, or can be integrated into another system, or some features can be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the components shown or discussed can be through some interfaces, and the indirect coupling or communication connection of devices or units can be electrical, mechanical or other forms.

[0165] The units described above as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units; they may be located in one place or distributed to multiple network units; some or all of the units may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. In addition, the functional units in the embodiments of the present application may be all integrated into one processing unit, or each unit may be separately used as a unit, or two or more units may be integrated into one unit; the above integrated units may be implemented in the form of hardware or in the form of hardware plus software functional units.

[0166] The above is only an implementation method of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed in the present application should be included in the protection scope of the present application.

Claims

1. A charging method, characterized in that: The charging method comprises: In the process of performing step-by-step constant voltage charging on the battery, collecting the state information of the battery in the current step and / or the accumulated state information in the current step; the step-by-step constant voltage charging includes at least two consecutive constant voltage charging steps; According to the state information and / or the accumulated state information, query a preset charging step table to determine the first charging cutoff condition of the current step and the target charging voltage of the next step; The preset charging step table includes: a mapping relationship between at least two state information of the battery, the first charging cut-off condition, and the target charging voltage; or, The preset charging step table includes: a mapping relationship between at least two accumulated state information of the battery, the first charging cut-off condition, and the target charging voltage; or, The preset charging step table includes: at least one state information and at least one accumulated state information of the battery, and a mapping relationship between the first charging cut-off condition and the target charging voltage; The state information is one of the following: the charging current of the battery, the charging rate of the battery, the temperature of the battery, and the state of charge of the battery; The accumulated status information is one of the following: charging time, charging power, charging energy, accumulated temperature rise and voltage change value of the battery at the current step; The first charging cut-off condition is set as follows: before the first charging cut-off condition is reached, the charging current of the battery is less than or equal to the charging capacity of the battery; The target charging voltage is configured such that: when the battery is charged with the target charging voltage, the charging current of the battery is less than or equal to the charging capacity of the battery; The charging capacity of the battery is related to at least one of the state of charge, cell system, impedance, polarization voltage and open circuit voltage of the battery; When the state information and / or the accumulated state information satisfies the corresponding first charging cut-off condition, the battery is charged for the next step based on the target charging voltage.

2. The charging method according to claim 1, characterized in that: Before performing the step-by-step constant voltage charging on the battery, the charging method further comprises: In the process of charging the battery using a first charging method, detecting a charging parameter of the battery, wherein the first charging method is different from the step-by-step constant voltage charging; When the charging parameters of the battery meet the preset conditions, determining that the battery reaches a polarization stable state; When the battery reaches the polarization stable state, the battery is subjected to the stepwise constant voltage charging.

3. The charging method according to claim 2, characterized in that: The charging parameter includes at least one of the following: a first duration of the first charging mode, a state of charge (SOC) of the battery, an SOC increment of the battery during the first duration, an increment of a battery capacity of the battery during the first duration, a temperature change of the battery during the first duration, a voltage of the battery during a preset time interval, and a voltage change of the battery during a preset time interval; The charging parameter satisfies a preset condition, including at least one of the following: the first duration is greater than or equal to a first time threshold; the SOC is greater than or equal to a first SOC threshold; The SOC increment is greater than or equal to a first SOC increment threshold; the battery capacity increment is greater than or equal to a first battery capacity increment threshold; the temperature change is greater than or equal to a first battery temperature rise threshold; The voltage of the battery within a preset time interval is less than or equal to a first voltage threshold; and the voltage variation of the battery within the preset time interval is less than the first voltage variation threshold.

4. The charging method according to claim 2, characterized in that: Before charging the battery using the first charging method, the method further includes: charging the battery using a second charging method, and when a second switching condition is met, charging the battery using the first charging method; Wherein, the first charging method and the second charging method are different; The second charging mode is any one of constant current charging, constant current and constant voltage combined charging, pulse charging, constant voltage charging and segmented constant voltage charging; The first charging mode is any one of constant current charging, constant current and constant voltage combined charging, pulse charging and constant voltage charging.

5. The charging method according to claim 1, characterized in that: The charging method further comprises: In the case where the current step is the first charging step of the step-by-step constant voltage charging, the charging step table is queried according to the battery status information at the initial moment of the step-by-step constant voltage charging to determine the charging voltage of the current step.

6. The charging method according to any one of claims 1 to 5, characterized in that: The battery includes one battery cell, and the temperature of the battery is the temperature of the one battery cell; or, The battery includes a plurality of battery cells, and the temperature of the battery is a maximum value, a minimum value, or an average value of the temperatures of the plurality of battery cells.

7. A charging device, characterized in that: include: A collection unit, used for collecting the state information of the battery in the current step and / or the accumulated state information in the current step during the process of performing step-by-step constant voltage charging on the battery; The step-by-step constant voltage charging includes at least two consecutive constant voltage charging steps; A first determining unit is used to query a preset charging step table according to the state information and / or the accumulated state information to determine the first charging cutoff condition of the current step and the target charging voltage of the next step; wherein, The preset charging step table includes: at least two state information of the battery, and the mapping relationship between the first charging cut-off condition and the target charging voltage; or, the preset charging step table includes: at least two accumulated state information of the battery, and the mapping relationship between the first charging cut-off condition and the target charging voltage; or, the preset charging step table includes: at least one state information and at least one accumulated state information of the battery, and the mapping relationship between the first charging cut-off condition and the target charging voltage; wherein the state information is one of the following: the charging current of the battery, the charging rate of the battery, the temperature of the battery, and and the state of charge of the battery; the accumulated state information is one of the following: the charging time, charging power, charging energy, accumulated temperature rise and voltage change value of the battery in the current step; the first charging cut-off condition is set to: before reaching the first charging cut-off condition, the charging current of the battery is less than or equal to the charging capacity of the battery; the target charging voltage is configured to: when charging the battery with the target charging voltage, the charging current of the battery is less than or equal to the charging capacity of the battery; the charging capacity of the battery is related to at least one of the state of charge, cell system, impedance, polarization voltage and open circuit voltage of the battery; A charging unit is configured to charge the battery for the next step based on the target charging voltage when the state information and / or the accumulated state information satisfies the corresponding first charging cut-off condition.

8. An electronic device, characterized in that: The device comprises a battery, a memory and a processor, wherein the memory is used to store a computer program, and when the battery is charged, the computer program is executed by the processor to implement the charging method according to any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that: Used to store a computer program, which implements the method according to any one of claims 1 to 6 when executed.

Images