Battery and charging method thereof, battery management system and electric equipment

Abstract

The invention provides a battery and a charging method thereof, a battery management system and electric equipment, which can improve the charging performance of the battery. The battery comprises at least one battery monomer and a battery management system, a positive electrode active material of the battery monomer comprises LiMPO4, and M comprises Mn element and Fe element; the battery management system is used for controlling the battery to carry out first constant current charging until the voltage of the battery is a first cut-off voltage; controlling the battery to perform constant-voltage charging; and controlling the battery to carry out second constant current charging until the voltage of the battery is a second cut-off voltage, and the second cut-off voltage is greater than the first cut-off voltage.

Description

Battery and charging method thereof, battery management system and electric device

[0001] This application claims priority to PCT application number PCT / CN2023 / 091303, filed with the Patent Office of China on April 27, 2023, entitled “Charging method, device, electronic device and computer-readable storage medium”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present application relates to the field of battery technology, and in particular, to a battery and a charging method thereof, a battery management system, and an electrical device. Background Art

[0003] With the development of the times, electric vehicles have huge market prospects due to their high environmental protection, low noise, low cost of use and other advantages. They can effectively promote energy conservation and emission reduction, which is beneficial to the development and progress of society.

[0004] Battery technology is a crucial factor in the development of electric vehicles. Therefore, improving battery charging performance has become a pressing issue.

[0005] Summary of the Invention

[0006] The present application provides a battery and a charging method thereof, a battery management system and an electrical device, which can improve the charging performance of the battery.

[0007] In a first aspect, a battery is provided, comprising at least one battery cell and a battery management system, wherein the positive electrode active material of the battery cell comprises LiMPO4, wherein M comprises Mn and Fe elements; the battery management system is configured to: control the battery to perform a first constant-current charge until the voltage of the battery reaches a first cutoff voltage; control the battery to perform a constant-voltage charge; and control the battery to perform a second constant-current charge until the voltage of the battery reaches a second cutoff voltage, wherein the second cutoff voltage is greater than the first cutoff voltage.

[0008] The battery in this application uses LiMPO4 material as its positive electrode active material, wherein M includes Mn element and Fe element, and has the advantages of high energy density and large capacity. However, when LiMPO4 material is used as the positive electrode active material of the battery, it will successively experience the charging platform corresponding to the Fe element and the charging platform corresponding to the Mn element during the charging process. In the voltage platform stage corresponding to the Mn element, it is difficult to remove the lithium of the positive electrode active material, making it difficult to fully utilize the capacity of the battery. For this reason, after the battery is subjected to constant current charging and constant voltage charging, it is supplemented by a small current to perform constant current charging on the battery to a higher voltage, which is conducive to the removal of lithium ions and enables the battery's capacity to be charged and discharged.

[0009] In some possible implementations, the battery management system is specifically used to: control the battery to perform constant voltage charging until the current of the battery is a first cutoff current, the first cutoff current is greater than a second cutoff current, and the second cutoff current is the current of the battery when the battery is subjected to the constant voltage charging until it is fully charged.

[0010] In this embodiment, since the current gradually decreases during the constant voltage charging stage and the first cutoff current is greater than the second cutoff current, the time spent on constant voltage charging to the first cutoff current is reduced compared to the case of constant voltage charging to the second cutoff current, thereby improving the charging efficiency.

[0011] In some possible implementations, the first cutoff current ranges from 0.02C to 0.1C; further, optionally, the first cutoff current ranges from 0.05C to 0.1C.

[0012] The first cutoff current is greater than the second cutoff current, and the second cutoff current may typically be 0.02C. Therefore, the first cutoff current may be set within a range of 0.02C to 0.1C. When LiMPO4 material is used as the positive electrode active material, the rate of lithium ion release decreases significantly after the battery is subjected to constant voltage charging to a current of 0.05C. Therefore, the first cutoff current may optionally be set within a range of 0.05C to save time after the current is less than 0.05C during the conventional constant voltage charging stage.

[0013] In some possible implementations, the first cut-off voltage is greater than or equal to a platform voltage corresponding to the Mn element in the positive electrode active material.

[0014] In this implementation, since the cathode is conducive to the release of lithium ions under overpotential conditions, the first cut-off voltage is set to be greater than or equal to the voltage platform corresponding to the Mn element. The voltage platform stage corresponding to the Mn element is conducive to the release of lithium ions of the positive electrode active material from the cathode.

[0015] In some possible implementations, the first cutoff voltage ranges from 3.97V to 4.15V; further, optionally, the first cutoff voltage ranges from 4.00V to 4.15V.

[0016] In this implementation, since the voltage platform corresponding to the Mn element is typically 3.97V, the first cutoff voltage needs to be greater than 3.97V to facilitate the release of lithium ions from the cathode. Furthermore, to reduce the oxidation of the electrode and electrolyte caused by an excessively high cutoff voltage, the first cutoff voltage needs to be less than or equal to 4.15V. Therefore, the first cutoff voltage can be within the range of 3.97V to 4.15V; further, optionally, the first cutoff voltage can be within the range of 4.0V to 4.15V.

[0017] In some possible implementations, a difference between the second cut-off voltage and the first cut-off voltage is between 0.1V and 0.3V.

[0018] In this implementation, the second cut-off voltage reached during the second constant-current charge is greater than the first cut-off voltage. By increasing the voltage to facilitate the release of lithium ions, the battery capacity is further increased. However, in order to reduce the time the battery is in the high-voltage stage and extend the battery life, the second cut-off voltage should not exceed the first cut-off voltage by much. Therefore, setting the difference between the second cut-off voltage and the first cut-off voltage within the range of 0.1V to 0.3V can not only increase the battery's charging capacity, but also reduce the impact on the battery's service life.

[0019] With reference to the preferred range of the first cut-off voltage, the range of the second cut-off voltage may include 4.1V to 4.3V; further, optionally, the range of the second cut-off voltage includes 4.15V to 4.25V.

[0020] The first charging current used in the first constant current charging may be within a suitable range to meet the charging requirements of the battery. Optionally, the first charging current used in the first constant current charging may range from 0.1C to 4C. For example, the first charging current may be 0.33C.

[0021] In some possible implementations, the second charging current used in the second constant-current charging is in a range of 0.01C to 0.1C.

[0022] In this implementation, after constant voltage charging, the battery is subjected to a second constant current charge, which can further increase the battery voltage, accelerate the delithiation of the cathode, and fully utilize the battery capacity. In order to reduce the length of time the battery is in the high voltage stage and reduce the occurrence of electrochemical oxidation within the battery, the second charging current used in the second constant current charge needs to be within an appropriate range. Optionally, the second charging current is within the range of 0.01C to 0.1C. For example, the second charging current is 0.5C.

[0023] In some possible implementations, the positive electrode active material includes at least one of the following materials:

[0024] LiMn 1-y Fe y PO4, where y is any value in the range of 0.001 to 0.5;

[0025] Li 1+t Mn 1-c Fe c P 1-z R z O4, 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 comprises one or more elements selected from B, S, Si and N;

[0026] Li 1+w C m Mn 1-u Fe u P 1-a R a O 4-n D n , wherein C includes one or more elements selected from Zn, Al, Na, K, Mg, Nb, Mo and W, R includes one or more elements selected from B, S, Si and N, 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.

[0027] In a second aspect, a method for charging a battery is provided, wherein the battery includes at least one battery cell, and the positive electrode active material of the battery cell includes LiMPO4, wherein M includes Mn element and Fe element, and the charging method includes: controlling the battery to perform a first constant current charging until the voltage of the battery is a first cutoff voltage; controlling the battery to perform constant voltage charging; and controlling the battery to perform a second constant current charging until the voltage of the battery is a second cutoff voltage, wherein the second cutoff voltage is greater than the first cutoff voltage.

[0028] In some possible implementations, controlling the battery to perform constant voltage charging includes: controlling the battery to perform constant voltage charging until the current of the battery is a first cutoff current, the first cutoff current is greater than a second cutoff current, and the second cutoff current is the current of the battery when the battery is subjected to the constant voltage charging until it is fully charged.

[0029] In some possible implementations, the first cutoff current ranges from 0.02C to 0.1C, or from 0.05C to 0.1C.

[0030] In some possible implementations, the first cut-off voltage is greater than or equal to a platform voltage corresponding to the Mn element in the positive electrode active material.

[0031] In some possible implementations, the first cut-off voltage ranges from 3.97V to 4.15V, or from 4.0V to 4.15V.

[0032] In some possible implementations, a difference between the second cut-off voltage and the first cut-off voltage is between 0.1V and 0.3V.

[0033] In some possible implementations, the second cut-off voltage ranges from 4.1V to 4.3V, or from 4.15V to 4.25V.

[0034] In some possible implementations, the first charging current used in the first constant-current charging is in a range of 0.1C to 4C.

[0035] In some possible implementations, the first charging current is 0.33C.

[0036] In some possible implementations, the second charging current used in the second constant-current charging is in a range of 0.01C to 0.1C.

[0037] In some possible implementations, the second charging current is 0.5C.

[0038] In some possible implementations, the positive electrode active material includes at least one of the following materials:

[0039] LiMn 1-y Fe y PO4, where y is any value in the range of 0.001 to 0.5;

[0040] Li 1+t Mn 1-c Fe c P 1-z R z O4, 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 comprises one or more elements selected from B, S, Si and N;

[0041] Li 1+w C m Mn1-u Fe u P 1-a R a O 4-n D n , wherein C includes one or more elements selected from Zn, Al, Na, K, Mg, Nb, Mo and W, R includes one or more elements selected from B, S, Si and N, 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.

[0042] In a third aspect, a battery management system is provided for executing the battery charging method described in the first aspect or any possible implementation of the first aspect, wherein the battery comprises at least one battery cell, and the positive electrode active material of the battery cell comprises LiMPO4, wherein M comprises Mn element and Fe element.

[0043] In a fourth aspect, an electrical device is provided, comprising the battery described in the first aspect or any possible implementation of the first aspect.

[0044] In a fifth aspect, a charging device is provided, comprising a processor and a memory, wherein the memory is used to store a computer program, and the processor is used to call and run the computer program stored in the memory to execute the method described in the above-mentioned second aspect or any possible implementation of the second aspect.

[0045] In a sixth aspect, a computer-readable storage medium is provided for storing a computer program, which, when executed by a computing device, enables the computing device to implement the method described in the second aspect or any implementation manner of the second aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without creative work.

[0047] FIG1 is a schematic block diagram of a charging system that may be used in an embodiment of the present application.

[0048] FIG2 is a schematic block diagram of a battery according to an embodiment of the present application.

[0049] FIG3 is a schematic diagram showing the changes in voltage and current during constant current charging and constant voltage charging.

[0050] FIG4 is a schematic flow chart of a battery charging method according to an embodiment of the present application.

[0051] FIG5 is a schematic diagram of an electrical device according to an embodiment of the present application. DETAILED DESCRIPTION

[0052] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0053] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used in this application and in the specification of the application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned figures are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship. "Vertical" is not strictly perpendicular, but is within the allowable error range. "Parallel" is not strictly parallel, but is within the allowable error range.

[0054] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the 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 in this application may be combined with other embodiments.

[0055] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "attached" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0056] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application indicates that the related objects are in an "or" relationship.

[0057] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are for illustrative purposes only and do not constitute any limitation on this application.

[0058] A battery generally refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. For example, the battery can be a battery module, where multiple battery cells are arranged and fixed to form a battery module. Another example is a battery pack, which includes battery cells and a casing, with the battery cells or battery modules housed in the casing.

[0059] The technical solutions described in the embodiments of the present application are applicable to various battery-using devices, such as mobile phones, portable devices, laptop computers, electric vehicles, electric toys, electric tools, electric vehicles, ships and spacecraft, etc. For example, spacecraft include airplanes, rockets, space shuttles and spacecraft, etc.

[0060] It should be understood that the technical solutions described in the embodiments of the present application are not limited to the devices described above, but can also be applied to all devices using batteries. However, for the sake of simplicity, the following embodiments are described using electric vehicles as an example.

[0061] Figure 1 shows an architecture diagram of a charging system 100 applicable to an embodiment of the present application. As shown in Figure 1, the charging system 100 includes a charging device 110 and a battery 120. Optionally, the battery 120 can be a battery in an electrical device such as a vehicle or a battery in other application scenarios.

[0062] Optionally, the battery 120 includes battery cells 121 and a battery management system (BMS) 122. The BMS 122 is used to monitor the status of the battery cells 121, perform intelligent management and maintenance on the battery cells 121, and reduce the probability of overcharging and overdischarging of the battery 120.

[0063] The charging device 110 is used to replenish the battery cells 121 in the battery 120 and / or control the discharge of the battery cells 121. For example, the charging device 110 can be a conventional charging station, a super charging station, a charging station supporting vehicle-to-grid (V2G) mode, a charger, or other charging device used to charge and / or discharge the battery. The embodiments of this application do not limit the specific type and specific application scenario of the charging device 110.

[0064] Optionally, as shown in FIG1 , the charging device 110 is connected to the battery cell 121 via a wire 150 and is connected to the BMS 122 via a communication line 140. The communication line 140 is used to implement information exchange between the charging device 110 and the BMS 122. By way of example, the communication line 140 includes, but is not limited to, a controller area network (CAN) communication bus or a daisy chain communication bus.

[0065] Optionally, the charging device 110 can communicate with the BMS 122 via a wireless network in addition to communicating with the BMS 122 via the communication line 140. The embodiment of the present application does not specifically limit the type of wired communication or wireless communication between the charging device 110 and the BMS 122.

[0066] As shown in FIG2 , an embodiment of the present application provides a battery 120 comprising at least one battery cell 121 and a battery management system 122. The positive electrode active material of the battery cell 121 is lithium manganese iron phosphate, hereinafter also referred to as LiMPO4, where M comprises Mn and Fe. The battery management system 122 is used to:

[0067] Controlling the battery 120 to perform a first constant current charge until the voltage of the battery 120 reaches a first cut-off voltage;

[0068] Controlling the battery 120 to perform constant voltage charging; and,

[0069] The battery 120 is controlled to perform a second constant current charge until the voltage of the battery 120 reaches a second cut-off voltage, which is greater than the first cut-off voltage.

[0070] That is, this embodiment is directed to a battery using LiMPO 4 as a positive electrode active material, and the charging process includes three stages: a first constant current charge→a constant voltage charge→a second constant current charge.

[0071] Here, the battery management system 122 may be, for example, the BMS 122 shown in FIG. 1 , or may be other control modules capable of controlling the temperature of the battery 120 .

[0072] Battery 120 includes at least one battery cell 121. The positive electrode active material of battery cell 121 is LiMPO4. The M element in the LiMPO4 material may include Mn and Fe. Compared to conventional batteries using LiFePO4 as the positive electrode active material, battery 120 using LiMPO4 as the positive electrode active material has a higher voltage platform and an energy density that is approximately 15% higher than that of batteries using LiFePO4. This offers advantages such as high energy density and large capacity, as well as lower cost and higher safety.

[0073] However, when LiMPO4 material is used as the positive electrode active material of battery 120, the charging process will successively experience the charging platform corresponding to the Fe element and the charging platform corresponding to the Mn element. During the charging platform corresponding to the Mn element, the delithiation depth of the positive electrode active material is low, making it difficult to fully utilize the capacity of battery 120, and the delithiation speed of the positive electrode active material is slow, which affects the charging performance of battery 120 and reduces the user experience.

[0074] The charging capacity of the battery 120 is closely related to the delithiation depth of the cathode. After the battery 120 is charged with a constant current until the voltage of the battery 120 reaches the cut-off voltage, the battery 120 is charged with a constant voltage to eliminate the polarization inside the battery cell 121, so that its capacity can be fully utilized. In batteries with traditional LFP and NCM chemical systems, the polarization of the battery cell mainly comes from the accumulated polarization of the battery before constant voltage charging. However, for the battery 120 using LiMPO4 material as the positive electrode active material, since the diffusion impedance of the charging platform stage corresponding to the Mn element in the LiMPO4 material is large, the difficulty of lithium ion removal increases. After the battery 120 is charged with a constant current until its voltage reaches the cut-off voltage, there are still many lithium ions that have not been completely removed. Therefore, constant voltage charging is required to completely remove the remaining lithium ions to fully utilize the capacity advantage of the material.

[0075] For batteries 120 with traditional LFP and NCM chemical systems, the constant voltage charging time is relatively short, and the cutoff current, for example, 0.02C, is usually reached in about 15 minutes. However, for batteries 120 using LiMPO4 material as the positive electrode active material, due to the relatively poor kinetic performance of the charging platform phase corresponding to the Mn element, the time for constant voltage charging to the cutoff current is much longer than the constant voltage charging time of batteries 120 with traditional LFP and NCM chemical systems. Of course, in order to give full play to the capacity of the battery 120, the battery 120 can be charged to a higher voltage for constant voltage charging. However, for batteries 120 using LiMPO4 material as the positive electrode active material, constant voltage charging at high voltage for a long time will cause the life of the battery 120 to be accelerated.

[0076] To this end, in the embodiment of the present application, after the battery 120 is subjected to constant current charging and constant voltage charging, the battery 120 is then assisted by a small current to perform constant current charging to a higher voltage, which is conducive to the release of lithium ions and enables the capacity of the battery 120 to be charged and discharged. Therefore, to a certain extent, the problem of the difficulty in fully utilizing the capacity brought about by using LiMPO4 material as the positive electrode active material of the battery 120 is solved.

[0077] It can be understood that in the embodiments of the present application, the charging platform refers to, for example, the stage in which the electrochemical reaction reaches an equilibrium state during the charging process, and the battery potential in the charging platform fluctuates less with the SOC, or in other words, the battery potential in the charging platform remains relatively stable.

[0078] In some embodiments, during the above-mentioned constant voltage charging stage, the battery management system 122 can control the battery 120 to perform constant voltage charging until the current of the battery 120 is a first cutoff current, wherein the first cutoff current is greater than the second cutoff current, and the second cutoff current is the current of the battery 120 when the battery 120 is constantly charged until it is fully charged.

[0079] Since the current gradually decreases during the constant voltage charging process, the current of the battery 120 when the battery 120 is charged at the constant voltage until the battery 120 reaches a fully charged state is the second cut-off current.

[0080] FIG3 shows the changes in voltage and current during constant current charging and constant voltage charging. As shown in FIG3 , during the constant current charging stage, the charging current of the battery 120 remains unchanged. At this time, the voltage of the battery 120 gradually increases until the voltage reaches the cut-off voltage and enters the constant voltage charging stage. During the constant voltage charging stage, the voltage of the battery 120 remains unchanged. At this time, the current of the battery 120 gradually decreases.

[0081] Typically, as shown in FIG3 , constant-current and constant-voltage charging of the battery 120 includes two stages. In the first stage, constant current charging is performed. When the voltage of the battery 120 reaches a first cutoff voltage, the battery 120 enters the second stage for constant-voltage charging. At this time, the current gradually decreases. When the charging current drops to the second cutoff current, the battery 120 reaches a fully charged state.

[0082] If the battery 120 is charged with a first constant current until its voltage reaches the first cut-off voltage, and the battery 120 is charged with a constant voltage until it is fully charged, the current of the battery 120 will gradually decrease to the second cut-off current during the constant voltage charging phase. At this time, the constant voltage charging takes a long time. In the embodiment of the present application, after the battery 120 is charged with a first constant current until its voltage reaches the first cut-off voltage, it is not necessary to charge the battery 120 directly until its current reaches the second cut-off current. Instead, the battery 120 is charged with a constant voltage until its current reaches the first cut-off current, wherein the first cut-off current is greater than the second cut-off current, and the battery 120 is continuously charged with a second constant current to increase the voltage of the battery 120, thereby saving the time it takes for the current of the battery 120 to charge from the first cut-off current to the second cut-off current during the constant voltage charging phase.

[0083] For example, assuming the first cutoff voltage is V1, the second cutoff voltage is V2, V2>V1, the first cutoff current is I1, the second cutoff current is I2, I1>I2. After the battery 120 is charged with a first constant-current charge to the first cutoff voltage V1, if the battery 120 is then charged with a constant voltage to a full charge state, the current is the second cutoff current I2. Assuming that the time consumed by this constant-voltage charging phase is T1; if the battery 120 is charged with a constant voltage charge to the first cutoff current I1, and then the battery 120 is charged with a second constant current charge to the voltage V2, the time consumed by the constant-voltage phase is T2. On the one hand, since the current gradually decreases during the constant voltage charging stage and I1>I2, T2<T1, which reduces the constant voltage charging time; on the other hand, since the battery 120 is charged to a higher voltage V2 with constant current after constant voltage charging, it is beneficial to accelerate the release of lithium ions, so that the capacity of the battery cell can be fully utilized, making up for the capacity that has not been utilized due to the shortening of the constant voltage charging time, and greatly reducing the time that the battery 120 is in the high voltage stage.

[0084] It can be seen that after the battery 120 is charged with the first constant current, the charging performance of the battery 120 can be significantly improved by combining the constant voltage charging and the second constant current charging.

[0085] It should be noted that before performing constant-current charging of the battery 120 to a higher voltage with the aid of a low current, the battery management system 122 may control the battery 120 to perform at least one constant-voltage charging and / or at least one constant-current charging. For example, after performing a first constant-current charging and constant-voltage charging of the battery 120 according to the charging method described above, the battery 120 may be charged with a second constant-current charging to a higher voltage with the aid of a low current. For another example, the battery 120 may be alternately charged with constant-current and constant-voltage charging multiple times, and then the battery 120 may be charged with a constant current to a higher voltage with the aid of a low current.

[0086] In some embodiments, the first cutoff current ranges from 0.02C to 0.1C; further, optionally, the first cutoff current ranges from 0.05C to 0.1C.

[0087] The first cutoff current achieved by the constant voltage charging in the embodiment of the present application is greater than the second cutoff current achieved by conventional constant voltage charging when the battery 120 is fully charged. Since the second cutoff current of the battery 120 is typically 0.02C when fully charged, the first cutoff current can be set within a range greater than 0.02C and less than or equal to 0.1C.

[0088] Furthermore, since when LiMPO4 material is used as the positive electrode active material, the rate of lithium ion release will seriously decrease after the battery is charged at a constant voltage to a current of 0.05C, the first cut-off current can be optionally set within a range greater than or equal to 0.05C and less than or equal to 0.1C to save time after the current is less than 0.05C in the constant voltage charging stage.

[0089] In some embodiments, the first cutoff voltage is greater than or equal to a plateau voltage corresponding to the Mn element in the positive electrode active material. Because the cathode is conducive to the release of lithium ions when overpotential is present, the first cutoff voltage is set to be greater than or equal to the voltage plateau corresponding to the Mn element. The voltage plateau corresponding to the Mn element facilitates the release of lithium ions from the positive electrode active material from the cathode.

[0090] For example, since the voltage platform corresponding to the Mn element is generally 3.97 V, the first cutoff voltage range can be set to be greater than 3.97 V. Furthermore, optionally, the first cutoff voltage range can be set to be greater than or equal to 4.00 V. Furthermore, to reduce the oxidation problem of the electrode and electrolyte caused by an excessively high cutoff voltage, the first cutoff voltage can be set to be less than or equal to 4.15 V.

[0091] In this way, setting the first cutoff voltage to greater than 3.97V and less than or equal to 4.15V, or further setting the first cutoff voltage to greater than or equal to 4.00V and less than or equal to 4.15V, is beneficial to the escape of lithium ions in the charging platform stage corresponding to the Mn element, and can also reduce the damage of high voltage to the battery cell 121.

[0092] The second cut-off voltage reached by the second constant current charging is greater than the first cut-off voltage reached by the first constant current charging, thereby facilitating the release of lithium ions by increasing the voltage, thereby further improving the battery capacity. However, in order to reduce the time that the battery is in the high-voltage stage and extend the life of the battery, the second cut-off voltage is not easy to exceed the first cut-off voltage by a large amount. Therefore, in some embodiments, the difference between the second cut-off voltage and the first cut-off voltage can be set in the range of 0.1V to 0.3V, that is, the difference between the second cut-off voltage and the first cut-off voltage is greater than or equal to 0.1V and less than or equal to 0.3V, which can not only improve the charging capacity of the battery, but also reduce the impact on the service life of the battery 120.

[0093] Referring to the preferred range of the aforementioned first cutoff voltage, the second cutoff voltage can be set to be greater than the first cutoff voltage, and the range of the second cutoff voltage can include 4.1V to 4.3V; further, optionally, the range of the second cutoff voltage can include 4.15V to 4.25V.

[0094] The first charging current used in the first constant current charging may be within a suitable range to meet the charging requirements of the battery. Optionally, the first charging current used in the first constant current charging may range from 0.1C to 4C. For example, the first charging current may be 0.33C.

[0095] After constant voltage charging, the battery 120 is subjected to a second constant current charge, which can further increase the voltage of the battery 120, accelerate the delithiation of the cathode, and fully utilize the capacity of the battery 120. In order to reduce the length of time that the battery 120 is in the high voltage stage and reduce the occurrence of electrochemical oxidation within the battery 120, the second charging current used in the second constant current charge needs to be within an appropriate range. Optionally, the second charging current used in the second constant current charge includes a range of 0.01C to 0.1C, for example, the second charging current is 0.5C.

[0096] It can be understood that the second charging current used for the second constant current charging can be greater than the first charging current used for the first constant current charging, the second charging current can also be less than the first charging current, or the second charging current can be equal to the first charging current, and this application does not limit this.

[0097] The following describes in detail the time required to charge the battery 120 based on different charging parameters and the results of the capacity test in conjunction with Table 1.

[0098] The negative electrode of the battery 120 used for testing is made of graphite, such as at least one of soft carbon, hard carbon, artificial graphite, and natural graphite. The graphite content of the negative electrode is 96.7%, the binder content is 1.5%, and the negative electrode coating weight is 0.163 mg / 1540 mm 2 , porosity is 27%, negative electrode coating thickness is 0.216mm, negative electrode compaction density is 1.65g / cm 3 .

[0099] The electrolyte of the battery cell 121 is selected from an electronically insulating and ion-conductive organic carbonate solution containing one or more organic carbonates such as ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate as solvents, and a solution containing one or more lithium salts selected from the group consisting of LiPF6, LiBF4, LiBOB, LiAsF6, Li(CF3SO2)2N, LiCF3SO3, and LiClO4 as solutes.

[0100] The separator of the battery cell 121 is selected from a film made of one or more electrochemically and chemically stable polyethylene, polypropylene, non-woven fabric, and polyfiber.

[0101] In the process of manufacturing the positive electrode sheet of the battery cell 121, the active material LiMPO4, the conductive carbon black Super-P, and the binder PVDF are fully stirred and mixed in the NMP solvent system according to the weight ratio of 97:1:2, and then coated on the Al foil, and the coating weight is controlled to be 360g / m 2 , drying, cold pressing, slitting and cutting to obtain the positive electrode sheet.

[0102] In the process of manufacturing the negative electrode of the battery cell 121, graphite, conductive carbon black Super-P, and binder SBR are mixed in a H20 solvent system according to a weight ratio of 97.4:0.8:1.8, and then coated on the Cu foil. The coating weight is controlled to be 0.163 mg / 1540 mm 2 , drying, cold pressing, slitting and cutting to obtain the negative electrode sheet.

[0103] When manufacturing the battery cell 121, a three-layer porous polymer film of PE / PP / PE is used as an isolating membrane. The positive electrode sheet, isolating membrane, and negative electrode sheet are wound in sequence. The winding controls the isolating membrane to be in the middle of the positive electrode sheet and the negative electrode sheet to play an isolating role. The winding controls the misalignment between the positive electrode sheet and the negative electrode sheet, as well as between the positive and negative electrode sheets and the diaphragm. After winding, a bare battery cell, i.e., an electrode assembly, is obtained. The electrode assembly is welded to the top cover of the battery cell 121 through the tabs, and the processes of shelling, baking, liquid injection, and formation are completed to obtain a qualified battery cell 121. The battery cell 121 can be used as the battery 120 to be tested, that is, the battery 120 is taken as an example including only one battery cell 121.

[0104] The specific charging process includes three charging stages: first, the battery 120 is charged with a first constant current at a first charging current (0.33C) until the voltage of the battery 120 reaches a first cutoff voltage V1 (4.00V to 4.15V); second, the battery 120 is charged with a constant voltage until the current of the battery 120 reaches a first cutoff current I1 (0.05C to 0.10C); and finally, the battery 120 is charged with a second constant current at a second charging current (0.01C to 0.10C) until the voltage of the battery 120 reaches a second cutoff voltage V2 (4.10V to 4.30V). Here, I1>I2, V2>V1.

[0105] The charging time of each stage was recorded, and the charging capacity and discharging capacity of the battery 120 were tested to obtain the results shown in Table 1.

[0106] Table 1

[0107] Battery 120 is charged with constant current and constant voltage using a conventional constant current and constant voltage charging scheme. For example, assuming the charging process for battery 120 includes: constant current charging of battery 120 using a first charging current of 0.33C until the voltage of battery 120 reaches a cutoff voltage V1' = 4.1V; then constant voltage charging of battery 120 until the current of battery 120 reaches a first cutoff current I1' = 0.02C. As can be seen from Table 1, the total charging time for battery 120 is T1 = 160 min + 120 min = 280 min, and the charge and discharge capacities of battery 120 are 143.6 Ah and 140.7 Ah, respectively.

[0108] Using the charging scheme of the embodiment of the present application, the battery 120 is subjected to a first constant current charge, a constant voltage charge, and a second constant current charge. As an example, assume that the charging process of the battery 120 includes: using a first charging current of 0.33C to charge the battery with a first constant current until the voltage of the battery 120 reaches a first cut-off voltage V1 = 4.1V; constant voltage charging the battery 120 until the current of the battery 120 reaches a first cut-off current I1 = 0.05C; and using a second charging current of 0.05C to charge the battery 120 with a second constant current until the voltage of the battery 120 reaches a second cut-off voltage V2 = 4.2V, wherein the first cut-off current I1 = 0.05C is greater than the first cut-off current I1' = 0.02C. That is, the constant voltage charge is stopped when the current of the battery 120 reaches 0.05C, and then the battery 120 is charged to a higher second cut-off voltage V2 = 4.2V through a second constant current charge, thereby fully utilizing the capacity of the battery 120. As can be seen from Table 1, in this case, the total charging time of the battery 120 is T2 = 160 min + 31 min + 21 min = 212 min, and the charging capacity and discharging capacity of the battery 120 are 147.4 Ah and 144.5 Ah, respectively.

[0109] It can be seen that in the former case, the charging time of the battery 120 is T1 = 280 minutes, and in the latter case, the charging time of the battery 120 is T2 = 212 minutes, where T2 < T1. Therefore, the charging scheme of the embodiment of the present application can significantly improve the charging efficiency of the battery 120.

[0110] Furthermore, it can be seen from the above description that the charging scheme of the embodiment of the present application saves charging time while having basically no effect on the charging capacity and discharging capacity of the battery 120 , and may even increase the charging capacity and discharging capacity of the battery 120 .

[0111] The above conclusions can be similarly drawn for the charging results under the other charging parameters in Table 1. For the sake of brevity, the comparison of charging time and charge / discharge capacity under the other charging parameters will not be repeated here.

[0112] It can be seen that the charging scheme of the embodiment of the present application can reduce the charging time of the battery 120, improve the charging efficiency, and is conducive to increasing the charging capacity of the battery 120, thereby improving the charging performance of the battery 120.

[0113] In addition, it can be seen from Table 1 that since the time of the second constant-current charging is significantly shorter than the time of the first constant-current charging and is also significantly shorter than the time of the constant-voltage charging, the battery 120 is under high voltage for a shorter time, which is beneficial to reducing the electrochemical oxidation inside the battery cell 121 and reducing the impact on the life of the battery 120.

[0114] The present application also provides a method 200 for charging the battery 120, for charging the battery 120. The method 200 may be executed by the battery management system 122. For example, as shown in FIG4 , the method 200 includes some or all of the following steps.

[0115] In step 210 , the battery 120 is controlled to perform a first constant current charge until the voltage of the battery 120 reaches a first cut-off voltage.

[0116] In step 220 , the battery 120 is controlled to perform constant voltage charging.

[0117] In step 230 , the battery 120 is controlled to perform a second constant current charge until the voltage of the battery 120 reaches a second cutoff voltage, wherein the second cutoff voltage is greater than the first cutoff voltage.

[0118] In some embodiments, controlling the battery 120 to perform constant voltage charging includes: controlling the battery 120 to perform constant voltage charging until the current of the battery 120 is a first cutoff current, wherein the first cutoff current is greater than the second cutoff current, and the second cutoff current is the current of the battery 120 when the battery 120 is constantly charged to a fully charged state.

[0119] In some embodiments, the first cutoff current ranges from 0.02C to 0.1C; further, optionally, the first cutoff current ranges from 0.05C to 0.1C.

[0120] In some embodiments, the first cut-off voltage is greater than or equal to a platform voltage corresponding to the Mn element in the positive electrode active material.

[0121] In some embodiments, the first cutoff voltage ranges from 3.97V to 4.15V; further, optionally, the first cutoff voltage ranges from 4.0V to 4.15V.

[0122] In some embodiments, the difference between the second cut-off voltage and the first cut-off voltage is between 0.1V and 0.3V.

[0123] In some embodiments, the second cutoff voltage ranges from 4.1V to 4.3V; further, optionally, the second cutoff voltage ranges from 4.15V to 4.25V.

[0124] In some embodiments, the first charging current used in the first constant current charging is in a range of 0.1 C to 4 C. For example, the first charging current is 0.33C.

[0125] In some embodiments, the second charging current used in the second constant current charging is in a range of 0.01C to 0.1C. For example, the second charging current is 0.5C.

[0126] It is understood that the specific details of the charging method 200 can be referred to the aforementioned description of the battery 120, and for the sake of brevity, they are not repeated here.

[0127] From the above description, it can be seen that in the embodiment of the present application, the battery 120 uses LiMPO4 material as its positive electrode active material. After the battery 120 is charged with a constant current for the first time until its voltage is a first cut-off voltage, the battery 120 is charged with a constant voltage until its current is a first cut-off current, wherein the first cut-off current is less than the second cut-off current, and the second cut-off current is the current of the battery 120 when the battery 120 is charged with the constant voltage until it is fully charged. Finally, the battery 120 is charged with a constant current for a second time with the aid of a small current until its voltage is a second cut-off voltage, wherein the second cut-off voltage is greater than the first cut-off voltage, and therefore is more conducive to the release of lithium ions, so that the capacity of the battery 120 can be charged and discharged, and since the constant voltage charging time is shortened, the charging efficiency is improved.

[0128] The embodiment of the present application can be applied to various types of batteries, especially the battery 120 using LiMPO4 material as the positive electrode active material, wherein M in the LiMPO4 material may include Mn and Fe. The LiMPO4 material is described in detail below.

[0129] As a way to realize LiMPO4 material, LiMPO4 can be chemically formulated as LiMn 1-y Fe y PO4 compound, wherein y is any value in the range of 0.001 to 0.5.

[0130] LiMn compound 0.80 Fe 0.20 PO4 as an example, for the compound LiMn 0.80 Fe 0.20 The preparation method of PO4 is described below. The preparation method may include the following steps.

[0131] In step S1 , Fe-doped manganese oxalate is prepared.

[0132] For example, 919.4 g of manganese carbonate and 231.7 g of ferrous carbonate can be added to a mixer and thoroughly mixed for 6 hours. The resulting mixture is then transferred to a reactor, 5 L of deionized water and 1260.6 g of oxalic acid dihydrate are added, and the mixture is heated to 80° C. and stirred at 500 rpm for 6 hours to mix uniformly, until the reaction terminates and no bubbles are generated, to obtain an Fe-doped manganese oxalate suspension. The suspension is then filtered, dried at 120° C., and sand-milled to obtain ferromanganese oxalate particles with a particle size of 100 nm.

[0133] In step S2, LiMn is prepared0.80 Fe 0.20 PO4.

[0134] For example, the manganese oxalate iron (C2O4Mn 0.80 Fe 0.20 1791.4 g of nitric acid (calculated as nitric acid 2H2O), 369.4 g of lithium carbonate, and 1150.1 g of ammonium dihydrogen phosphate were added to 20 L of deionized water and stirred thoroughly. The mixture was uniformly mixed and reacted 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 such as 90% nitrogen and 10% hydrogen.

[0135] As another implementation of LiMPO4 material, LiMPO4 can be chemically 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, S, Si and N.

[0136] The values ​​of t, c, and z are configured so that the entire compound remains electrically neutral. Optionally, the ratio of c to 1-c can be 1:10 to 1:1, further 1:4 to 1:1, where c represents the sum of the stoichiometric amounts of the Mn-site doping elements Fe. Optionally, the ratio of z to 1-z can be 1:9 to 1:999, further 1:499 to 1:249, where z represents the sum of the stoichiometric amounts of the P-site doping elements R.

[0137] For example, the 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] In step S1, a manganese source, an iron source, and an acid are dissolved in a solvent and stirred to generate a suspension of a manganese salt doped with elemental Fe. The suspension is filtered and a filter cake is dried to obtain a manganese salt doped with elemental Fe.

[0139] In step S2, a lithium source, a phosphorus source, a source of element R, a solvent, and the manganese salt doped with element Fe obtained in step S1 are added to a reaction container, ground and mixed to obtain a slurry.

[0140] In step S3, the slurry obtained in step S2 is transferred to a spray drying device for spray drying and granulation to obtain granules.

[0141] In step S4, the particles obtained in step S3 are sintered to obtain a positive electrode active material.

[0142] The manganese source is, for example, a manganese-containing substance that can be used to prepare lithium manganese phosphate, including but not limited to one or a combination of elemental manganese, manganese dioxide, manganese phosphate, manganese oxalate, and manganese carbonate. The iron source is, for example, selected from at least one of elemental iron, oxides, phosphates, oxalates, carbonates, and sulfates. The acid is, for example, selected from one or more of hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, and organic acids, such as oxalic acid. The source of element R is, for example, selected from at least one of element R sulfates, borates, nitrates, and silicates.

[0143] Compound Li 1.001 Mn 0.999 Fe 0.001 P 0.999 Si 0.001 For example, O4 can be prepared by:

[0144] In step S1 , Fe-doped manganese oxalate is prepared.

[0145] For example, 1148.2 g of manganese carbonate and 1.2 g of ferrous carbonate were added to a mixer and thoroughly mixed for 1 hour. The resulting mixture was then transferred to a reactor, 5 L of deionized water and 1260.6 g of oxalic acid dihydrate were added, and the mixture was heated to 80° C. and stirred at 500 rpm for 6 hours to mix uniformly until the reaction terminated and no bubbles were generated, thereby obtaining 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 100 nm.

[0146] Step S2: Preparation of Li 1.001 Mn 0.999 Fe 0.001 P 0.999 Si 0.001 O4.

[0147] Take the manganese oxalate iron (C2O4Mn 0.999 Fe 0.0011789.6 g of nitric acid (calculated as nitric acid, 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, such as 90% nitrogen and 10% hydrogen.

[0148] As another implementation of LiMPO4 material, LiMPO4 can be chemically 1+w C m Mn 1-u Fe u P 1-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, S, Si, and N, D comprises one or more elements selected from S, F, Cl, and Br, w is any value within the range of -0.100 to 0.100, u is any value within the range of 0.001 to 0.500, a is any value within the range of 0.001 to 0.100, n is any value within the range of 0.001 to 0.1, and m is any value within the range of 0.9 to 1.1.

[0149] Similarly, the values ​​of w, u, a, and m described above are configured so that the entire compound remains electrically neutral.

[0150] For example, the 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.

[0151] In step S1, a manganese source, an iron source, and an acid are dissolved in a solvent and stirred to generate a suspension of a manganese salt doped with elemental Fe. The suspension is filtered and a filter cake is dried to obtain a manganese salt doped with elemental Fe.

[0152] In step S2, 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 element Fe obtained in step S1 are added to a reaction container, ground and mixed to obtain a slurry.

[0153] In step S3, the slurry obtained in step S2 is transferred to a spray drying device for spray drying and granulation to obtain granules.

[0154] In step S4, the particles obtained in step S3 are sintered to obtain a positive electrode active material.

[0155] The source of element C is, for example, selected from at least one of a simple substance, oxide, phosphate, oxalate, carbonate, and sulfate of element C. The manganese source is, for example, a manganese-containing substance that can be used to prepare lithium manganese phosphate, including but not limited to one or a combination of simple manganese, manganese dioxide, manganese phosphate, manganese oxalate, and manganese carbonate. The iron source is, for example, selected from at least one of a simple substance, oxide, phosphate, oxalate, carbonate, and sulfate of iron. The acid is, for example, selected from one or more of hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, and an organic acid, and may be, for example, oxalic acid. The source of element R is, for example, selected from at least one of a sulfate, borate, nitrate, and silicate of element R. The source of element D is, for example, selected from at least one of a simple substance and an ammonium salt of element D.

[0156] The positive electrode active material may contain Li 1+w C m Mn 1-u Fe u P 1-a R a O 4-n D nIn the case of , 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 less, 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.

[0157] 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, in a doping site with the chemical formula Li 1+w Mn 1- u Fe u P 1-a R aIn the case of a compound containing O4, if 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 specified for z 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 of the stoichiometric number of C also has the above meaning.

[0158] The present application also provides a battery management system 122 for executing the charging method 200 of the battery 120 described in any of the above embodiments. The battery 120 includes at least one battery cell 121. The positive electrode active material of the battery cell 121 includes LiMPO4, where M includes Mn and Fe elements.

[0159] The present application also provides an electrical device, comprising the battery 120 described in any of the above embodiments, and the battery 120 is used to provide power for the electrical device.

[0160] The electrical device may be, for example, a mobile phone, a portable device, a laptop computer, an electric vehicle, an electric toy, an electric tool, an electric vehicle, a ship, and a spacecraft, etc. For example, the spacecraft includes an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0161] As an example, as shown in FIG5 , it is a structural schematic diagram of a vehicle 1 according to an embodiment of the present application. The vehicle 1 may be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A motor 30, a controller 20 and a battery 120 may be provided inside the vehicle 1. The controller 20 is used to control the battery 120 to supply power to the motor 30. For example, a battery 120 may be provided at the bottom, front or rear of the vehicle 1. The battery 120 may be used to power the vehicle 1. For example, the battery 120 may be used as an operating power source for the vehicle 1, for the circuit system of the vehicle 1, for example, for the working power requirements during the start-up, navigation and operation of the vehicle 1. In another embodiment of the present application, the battery 120 may not only serve as an operating power source for the vehicle 1, but also as a driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0162] The present application also provides a computer-readable storage medium for storing a computer program. When the computer program is executed by a computing device, the computing device implements the method executed by the battery management system 122 in any of the above embodiments. Optionally, the computer program can be the computer program in the battery management system 122 described above.

[0163] It should be noted that, under the premise of no conflict, the various embodiments and / or technical features in each embodiment described in this application can be arbitrarily combined with each other, and the technical solution obtained after the combination should also fall within the scope of protection of this application.

[0164] In various embodiments of the present application, the size of the serial number of each process does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0165] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0166] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0167] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0168] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and components may be substituted with equivalents without departing from the scope of the present application. In particular, the various technical features described in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present application is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions within the scope of the claims.

Claims

1. A battery, characterized in that: include: at least one battery cell, wherein the positive electrode active material of the battery cell comprises LiMPO4, wherein M comprises Mn element and Fe element; and Battery management systems for: Controlling the battery to perform a first constant current charge until the voltage of the battery reaches a first cut-off voltage; controlling the battery to perform constant voltage charging; and, The battery is controlled to perform a second constant current charge until the voltage of the battery reaches a second cut-off voltage, where the second cut-off voltage is greater than the first cut-off voltage.

2. The battery according to claim 1, characterized in that The battery management system is specifically used for: The battery is controlled to perform constant voltage charging until the current of the battery is a first cutoff current, the first cutoff current is greater than a second cutoff current, and the second cutoff current is the current of the battery when the battery is subjected to the constant voltage charging until a full charge state.

3. The battery according to claim 2, characterized in that The first cut-off current ranges from 0.02C to 0.1C, or from 0.05C to 0.1C.

4. The battery according to any one of claims 1 to 3, characterized in that The first cut-off voltage is greater than or equal to a platform voltage corresponding to the Mn element in the positive electrode active material.

5. The battery according to claim 4, characterized in that The first cut-off voltage ranges from 3.97V to 4.15V, or from 4.0V to 4.15V.

6. The battery according to any one of claims 1 to 5, characterized in that The difference between the second cut-off voltage and the first cut-off voltage is between 0.1V and 0.3V.

7. The battery according to claim 6, characterized in that The second cut-off voltage ranges from 4.1V to 4.3V, or from 4.15V to 4.25V.

8. The battery according to any one of claims 1 to 7, characterized in that The first charging current used in the first constant current charging ranges from 0.1C to 4C.

9. The battery according to claim 8, characterized in that The first charging current is 0.33C.

10. The battery according to any one of claims 1 to 9, characterized in that The second charging current used in the second constant current charging includes a range of 0.01C to 0.1C.

11. The battery according to claim 10, characterized in that The second charging current is 0.5C.

12. The battery according to any one of claims 1 to 11, characterized in that The positive electrode active material includes at least one of the following materials: LiMn 1-y Fe y PO4, where 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, 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, 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 C includes one or more elements selected from Zn, Al, Na, K, Mg, Nb, Mo and W, R includes one or more elements selected from B, S, Si and N, and D includes one or more elements selected from S, F, One or more elements of 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.

13. A battery charging method, characterized in that: The battery comprises at least one battery cell, the positive electrode active material of the battery cell comprises LiMPO4, wherein M comprises Mn element and Fe element, and the charging method comprises: Controlling the battery to perform a first constant current charge until the voltage of the battery reaches a first cut-off voltage; controlling the battery to perform constant voltage charging; and, The battery is controlled to perform a second constant current charge until the voltage of the battery reaches a second cut-off voltage, where the second cut-off voltage is greater than the first cut-off voltage.

14. The charging method according to claim 13, characterized in that: The controlling the battery to perform constant voltage charging comprises: The battery is controlled to perform constant voltage charging until the current of the battery is a first cutoff current, the first cutoff current is greater than a second cutoff current, and the second cutoff current is the current of the battery when the battery is subjected to the constant voltage charging until a full charge state.

15. The charging method according to claim 14, characterized in that: The first cut-off current ranges from 0.02C to 0.1C, or from 0.05C to 0.1C.

16. The charging method according to any one of claims 13 to 15, characterized in that: The first cut-off voltage is greater than or equal to a platform voltage corresponding to the Mn element in the positive electrode active material.

17. The charging method according to claim 16, characterized in that: The first cut-off voltage ranges from 3.97V to 4.15V, or from 4.0V to 4.15V.

18. The charging method according to any one of claims 13 to 17, characterized in that: The difference between the second cut-off voltage and the first cut-off voltage is between 0.1V and 0.3V.

19. The charging method according to claim 18, characterized in that: The second cut-off voltage ranges from 4.1V to 4.3V, or from 4.15V to 4.25V.

20. The charging method according to any one of claims 13 to 19, characterized in that: The first charging current used in the first constant current charging ranges from 0.1C to 4C.

21. The charging method according to claim 20, characterized in that: The first charging current is 0.33C.

22. The charging method according to any one of claims 13 to 21, characterized in that: The second charging current used in the second constant current charging includes a range of 0.01C to 0.1C.

23. The charging method according to claim 22, characterized in that: The second charging current is 0.5C.

24. The charging method according to any one of claims 13 to 23, characterized in that: The positive electrode active material includes at least one of the following materials: LiMn 1-y Fe y PO4, where 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, 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, 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 C includes one or more elements selected from Zn, Al, Na, K, Mg, Nb, Mo and W, R includes one or more elements selected from B, S, Si and N, and D includes one or more elements selected from S, F, One or more elements of 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.

25. A battery management system, characterized in that: A method for charging a battery according to any one of claims 13 to 24, wherein the battery comprises at least one battery cell, wherein a positive electrode active material of the battery cell comprises LiMPO4, wherein M comprises Mn element and Fe element.

26. An electrical equipment, characterized in that: Comprising a battery according to any one of claims 1 to 12.

27. A computer-readable storage medium, characterized in that: Used to store a computer program, which, when executed by a computing device, enables the computing device to implement the charging method according to any one of claims 13 to 24.

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