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

Abstract

The application relates to the field of batteries, and discloses a battery charging method, a controller, a battery management system, a battery and a power utilization device. The battery charging method comprises the following steps: obtaining an electrical parameter of the battery; and determining whether the electrical parameter of the battery reaches a preset threshold value; wherein the value range of the preset threshold value satisfies the following condition: the state of charge (SOC) of the battery corresponding to the preset threshold value is 70-80%; when the electrical parameter of the battery reaches the preset threshold value, the charging of the battery is controlled to be paused, and the battery is controlled to be discharged for a time t; and when the discharging is completed, the charging of the battery is controlled to be continued. According to the application, the preset threshold value of the electrical parameter is set, the charging is paused and the battery is discharged when the SOC of the battery reaches the preset threshold value, the lithium precipitation of the battery can be reduced, and the safety performance of the battery is improved; the preset threshold value is selected in the SOC range of 70-80%, so that the lithium precipitation of the battery can be reduced in a better way on the basis of reducing the influence on the charging time as much as possible.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of batteries, in particular to a battery charging method, a controller, a battery management system, a battery and a power consumption device. BACKGROUND

[0002] With the wide application of lithium ion batteries in new energy vehicles, energy storage and other fields, higher requirements are put forward for the charging speed of lithium ion batteries.

[0003] The improvement of the battery charging speed will result in the increasing of the battery charging rate, and the large battery rate will increase the battery polarization, and the lithium ions on the negative electrode surface will be seriously accumulated, the negative electrode potential will be greatly reduced, and the lithium precipitation potential will be closer to 0V, which will greatly increase the risk of lithium precipitation during charging. When lithium precipitation occurs in the negative electrode, the lithium dendrites precipitated may react with the electrolyte to locally generate a large amount of heat or pierce the isolation membrane of the battery to cause positive and negative short circuits, and even cause the battery to catch fire and explode, which is an important factor threatening the safety of battery use today and in the future. Therefore, how to reduce the lithium precipitation of the battery during charging is a technical problem to be solved at present. SUMMARY

[0004] The present application provides a battery charging method, a controller, a battery management system, a battery and a power consumption device to reduce lithium precipitation of the battery.

[0005] According to a first aspect of the present application, a battery charging method is provided, comprising: obtaining an electrical parameter of the battery; determining whether the electrical parameter of the battery reaches a preset threshold; wherein the value range of the preset threshold satisfies the following condition: the state of charge (SOC) of the battery corresponding to the preset threshold is 70-80%; when the electrical parameter of the battery reaches the preset threshold, controlling to pause charging the battery and controlling the battery to discharge for a time t; and when the discharging ends, controlling to continue charging the battery.

[0006] The technical scheme of the embodiment of the present application sets the preset threshold of the electrical parameter, pauses charging and discharges when the SOC of the battery reaches the preset threshold, which can reduce lithium precipitation of the battery and improve the safety performance of the battery; at the same time, the value range of the preset threshold satisfies that the SOC of the battery corresponding to the preset threshold is 70-80%, and selecting the preset threshold in this range can achieve a good effect of reducing lithium precipitation of the battery on the basis of as low as possible influence on the charging time.

[0007] In some embodiments, the negative electrode material of the battery includes graphite, and the electrical parameter is the SOC.

[0008] For the battery using graphite as the negative electrode material, the voltage charging curve in the charging process includes a jump stage and a stable stage, if voltage is used as the electrical parameter, it will lead to that the stable stage of voltage cannot accurately determine whether the electrical parameter of the battery reaches the preset threshold, in the embodiment, SOC is used as the electrical parameter, which can overcome the above defects, accurately determine whether the electrical parameter of the battery reaches the preset threshold, and further reduce lithium precipitation of the battery and improve the safety performance of the battery.

[0009] In some embodiments, the electrical parameter is voltage in the voltage jump stage of the battery charging process, and the electrical parameter is SOC in the voltage stable stage of the battery charging process.

[0010] In such embodiments, voltage is used as the electrical parameter in the voltage jump stage of the battery charging, and in the voltage stable stage, voltage with no large change amplitude is not used as the electrical parameter, and SOC is used as the electrical parameter instead, which can overcome the defect that the electrical parameter of the battery cannot be accurately determined by voltage in the voltage stable stage, accurately determine whether the electrical parameter of the battery reaches the preset threshold, further reduce lithium precipitation of the battery, and improve the safety performance of the battery.

[0011] In some embodiments, the preset threshold includes a first preset threshold and a second preset threshold, the value range of the first preset threshold satisfies the following condition: the SOC corresponding to the first preset threshold is 35-45%, and the value range of the second preset threshold satisfies the following condition: the SOC corresponding to the second preset threshold is 70-80%.

[0012] By using two different preset thresholds, the first discharge can be performed when the battery reaches the SOC state corresponding to the first preset threshold, which can ensure that the lithium precipitation caused by unreasonable current design or actual current greater than requested current, etc. in the early charging stage is timely embedded into the positive active material in the discharging process, and the amount of lithium precipitation is reduced. Considering the demand of fast charging battery, the design of rate, the change of negative electrode potential and other characteristics, the SOC corresponding to the first preset threshold of the first discharge is set to the range of 35-45%, which can achieve good effects of promoting the precipitation of lithium metal and reducing the continuous growth of lithium dendrites; the second discharge is performed when the battery reaches the SOC state corresponding to the second preset threshold, which can further reduce the lithium precipitation of the battery in the later charging stage, and selecting the second discharge preset threshold in the range of 70-80% can achieve good effects of reducing the lithium precipitation of the battery, thereby improving the safety performance of the battery.

[0013] In some embodiments, the preset threshold includes a first preset threshold and a second preset threshold, the first preset threshold is smaller than the second preset threshold; and the controlling to suspend charging the battery and to discharge the battery for t time when the electrical parameter of the battery reaches the preset threshold includes: controlling to suspend charging the battery and to discharge the battery for t1 time when the electrical parameter of the battery reaches the first preset threshold; and controlling to suspend charging the battery and to discharge the battery for t2 time when the electrical parameter of the battery reaches the second preset threshold; wherein t1 < t2.

[0014] By adopting two different preset thresholds, and discharging for a longer time t2 when the electrical parameter of the battery reaches the larger second preset threshold than when the electrical parameter of the battery reaches the smaller first preset threshold, the battery can be discharged for a longer time when more lithium is precipitated, and a better effect of reducing lithium precipitation of the battery can be achieved, thereby improving the safety performance of the battery.

[0015] In some embodiments, the method further includes: determining whether the electrical parameter of the battery satisfies a condition of stopping charging; stopping charging when the electrical parameter of the battery satisfies the condition of stopping charging; determining whether the electrical parameter of the battery reaches a preset threshold; wherein the preset threshold has a value range satisfying the following condition: the SOC corresponding to the preset threshold is 70-80%; and controlling to discharge the battery for t time when the electrical parameter of the battery reaches the preset threshold.

[0016] The above manner determines whether the electrical parameter of the battery reaches the preset threshold again after stopping charging, and selects the preset threshold in the range of 70-80% of the SOC corresponding to the preset threshold, and discharges the battery when the preset threshold is reached, so that the battery can be discharged when lithium precipitation of the battery needs to be reduced after stopping charging, and a better effect of reducing lithium precipitation of the battery can be achieved.

[0017] According to a second aspect of the present application, a charging controller of a battery is provided, including: one or more processors working individually or collectively, the processors being configured to perform the steps of the charging method of the battery described in the first aspect above.

[0018] According to a third aspect of the present application, a battery management system is provided, including: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to cause the at least one processor to implement the steps of the charging method of the battery described in the first aspect above.

[0019] According to a fourth aspect of the present application, there is provided a battery comprising the charge controller of the battery as described in the second aspect above, or the battery management system as described in the third aspect above.

[0020] According to a fifth aspect of the present application, there is provided an electrical device comprising the battery as described in the fourth aspect above, the battery being configured to provide electrical energy. BRIEF DESCRIPTION OF DRAWINGS

[0021] The accompanying drawings, which are included to provide a further understanding of the present application and are incorporated in and constitute a part of this application, illustrate embodiments of the present application and together with the description serve to explain the present application. In the drawings:

[0022] Figure 1 Flowchart of the charging method of the battery of some embodiments of the present application;

[0023] Figure 2 Voltage charging curve of the battery employing lithium iron phosphate as the positive electrode material during the charging process;

[0024] Figure 3 Flowchart of the charging method of the battery of some embodiments of the present application;

[0025] Figure 4 Flowchart of the charging method of the battery of some embodiments of the present application;

[0026] Figure 5 Structure diagram of the charging circuit of the battery of some embodiments of the present application;

[0027] Figure 6 Structure diagram of the charge controller of the battery of some embodiments of the present application;

[0028] Figure 7 Structure diagram of the battery management system of some embodiments of the present application;

[0029] Figure 8 Structure diagram of the battery of some embodiments of the present application;

[0030] Figure 9 Structure diagram of the battery of some embodiments of the present application;

[0031] Figure 10 Structure diagram of the electrical device of some embodiments of the present application. DETAILED DESCRIPTION

[0032] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of the present application.

[0033] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as those commonly understood by one of ordinary skill in the art to which this application belongs; the terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application; the terms "include" and "have" and any variations thereof in the specification and claims of the present application and the above description of drawings are intended to cover non-exclusive inclusion. The terms "first", "second" and the like in the specification and claims of the present application and the above description of drawings are used to distinguish different objects, not to describe a particular order or primary and secondary relationship. In the description of the present application, unless otherwise stated, the meaning of "a plurality of" is two or more.

[0034] In the present application, the term "embodiment" means that the specific features, structures or properties described in conjunction with the embodiment can be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in the present application can be combined with other embodiments.

[0035] As described above, it should be emphasized that when the term "include / contain" is used in the present specification, it is used to explicitly indicate the presence of the described features, integers, steps or components, but does not exclude the presence or addition of one or more other features, integers, steps, components or groups of features, integers, steps, components. As used in the present application, the singular forms "one", "a" and "the" also include the plural forms unless the context clearly indicates otherwise.

[0036] The word "one" in the specification can mean one, but can also be consistent with the meaning of "at least one" or "one or more". The term "about" generally means the value mentioned plus or minus 10%, or more specifically plus or minus 5%. The term "or" used in the claims means "and / or" unless it is explicitly indicated that it refers to only alternative solutions.

[0037] The term "and / or" in the present application is only used to describe the relationship between the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " in the present application generally represents an "or" relationship between the front and rear associated objects.

[0038] The batteries mentioned in the art can be divided into primary batteries and rechargeable batteries according to whether they can be charged. Primary batteries, also known as "throwaway" batteries and primary batteries, cannot be charged for use after their power is depleted and can only be discarded. Rechargeable batteries, also known as secondary batteries or secondary batteries, are different from primary batteries in terms of manufacturing materials and processes. The advantage is that they can be used multiple times after charging. The output current load of rechargeable batteries is higher than that of most primary batteries. The common types of rechargeable batteries currently available are: lead-acid batteries, nickel-hydrogen batteries, and lithium-ion batteries. Lithium-ion batteries have the advantages of light weight, large capacity (the capacity is 1.5 times to 2 times that of nickel-hydrogen batteries of the same weight), no memory effect, and very low self-discharge rate. Therefore, even though the price is relatively high, they are still widely used. Lithium-ion batteries are also used in pure electric vehicles and hybrid vehicles. Lithium-ion batteries used for such purposes have a relatively low capacity, but have a large output, a high charging current, and a long service life, but the cost is high.

[0039] The batteries described in the embodiments of the present application refer to rechargeable batteries. Hereinafter, the concept of the present application will be described mainly by taking lithium-ion batteries as an example. It should be understood that any other suitable type of rechargeable battery is applicable. The batteries mentioned in the embodiments of the present application refer to a single physical module that includes one or more battery monomers (also known as battery cells) to provide higher voltage and capacity. For example, the batteries mentioned in the present application can include battery modules or battery packs, etc. The battery monomer includes a positive electrode sheet, a negative electrode sheet, an electrolyte, and a separator, which is the basic structural unit of battery modules and battery packs. Common positive electrode materials for lithium-ion batteries include lithium cobaltate, lithium manganate, lithium nickelate, lithium iron phosphate, and ternary materials (such as lithium nickel cobalt manganate), etc. Common negative electrode materials include carbon materials (such as graphite) and silicon-based materials, etc. Common separator materials include polyethylene (PE) or polypropylene (PP) based polyolefin materials. Battery monomers are generally divided into three types according to the packaging method: cylindrical battery monomers, square battery monomers, and soft-packaged battery monomers.

[0040] A plurality of battery cells can be connected in series and / or parallel via electrode terminals for various applications. In some high-power applications such as electric vehicles, the application of batteries includes three levels: battery cells, battery modules, and battery packs. A battery module is formed by electrically connecting a certain number of battery cells together and placing them in a frame to protect the battery cells from external impacts, heat, vibration, etc. A battery pack is the final state of the battery system installed in an electric vehicle. Most current battery packs are made by assembling battery management systems (BMS), thermal management components, and various control and protection systems on one or more battery modules. With the development of technology, the level of battery module can be omitted, that is, the battery pack is directly formed by battery cells. This improvement enables the weight energy density and volume energy density of the battery system to be improved while the number of parts is significantly reduced. The battery referred to in this application includes a battery module or a battery pack.

[0041] With the wide application of lithium ion batteries in new energy vehicles, energy storage and other fields, higher requirements are put forward for the charging speed of lithium ion batteries. For lithium ion batteries with graphite as the main negative electrode material, the increase of battery charging speed means the increase of charging rate, which will cause serious accumulation of lithium ions on the surface of graphite, increase the polarization of the battery, and increase the risk of lithium precipitation during charging. Lithium dendrites precipitated on the surface of the negative electrode may pierce the isolation membrane of the battery, causing short circuit between the positive and negative electrodes, and even causing the battery to catch fire and explode, reducing the safety performance of the battery. Therefore, how to reduce the lithium precipitation of the battery during charging is a technical problem that needs to be solved at present.

[0042] At present, the chemical system of the battery is improved or the charging rate is reduced to reduce the polarization of the battery and reduce the probability of lithium precipitation during charging. The above-mentioned way of improving the chemical system of the battery increases the production cost, and the way of reducing the charging rate prolongs the charging time at the cost, which seriously affects the user experience.

[0043] The present inventors have found that by introducing discharging during charging, the accumulation of battery polarization can be reduced, and the precipitated lithium metal can be promoted to re-embed through discharging, thereby inhibiting the continuous accumulation of precipitated lithium metal. This way has lower cost, higher efficiency of inhibiting lithium precipitation, and does not need to significantly reduce the charging rate, which can improve the safety performance of the electric device while ensuring the performance of the electric device.

[0044] In theory, from the rule that the negative electrode potential decreases as the State of Charge (SOC) of the battery increases, if discharging is performed when the State of Charge of the battery is 100%, or when the SOC corresponding to the voltage (or the maximum voltage of the battery pack) of the battery is 100%, the best effect of inhibiting lithium precipitation of the battery can be achieved.

[0045] However, the inventors have found through a large number of researches and experiments that the above method cannot actually achieve the best effect of inhibiting lithium precipitation of the battery. Specifically, when the battery is fast-charged, the upper limit SOC of fast-charging is generally 80% SOC, and the rate of the battery above 80% SOC is small, so the most dangerous SOC range of lithium precipitation of the actual battery during fast-charging is 80% and below. Considering the rule that the negative electrode potential of the battery with graphite as the negative electrode decreases with the increase of SOC, the characteristics that the fast-charging capacity of the lithium battery is high at low SOC, and the dangerous SOC range of fast-charging lithium precipitation is 70-80%, followed by below 70%.

[0046] In order to ensure that the precipitated metal lithium is timely embedded back into the positive electrode through discharging, the timing of introducing discharging during charging needs to be properly set. If discharging is introduced too early or after charging is completed, the charging time will be prolonged and there will be no obvious improvement in charging safety. How to achieve the best effect of inhibiting lithium precipitation of the battery on the basis of as little as possible affecting the charging time is a difficult technical problem for researchers and those skilled in the art.

[0047] In order to solve or at least partially solve the above problems and other potential problems existing in the prior art, the inventors of the present application propose a battery charging method, a controller, a battery management system, a battery and an electric device, and the design thereof will be specifically described below. It can be understood that the battery charging method, the controller, the battery management system, the battery described in the embodiments of the present application are applicable to various devices using batteries, for example, mobile phones, portable devices, notebook computers, electric vehicles, electric vehicles, ships, spacecraft, electric toys and electric tools, etc., for example, spacecraft includes airplanes, rockets, space shuttles and spacecraft, etc., electric toys include fixed or mobile electric toys, for example, game consoles, electric car toys, electric ship toys and electric plane toys, etc., electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools and railway electric tools, for example, electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators and electric planes. The electric device also includes the above-mentioned various devices.

[0048] The battery charging method, the controller, the battery management system, the battery and the electric device described in the embodiments of the present application are not only limited to the above-mentioned devices, but also applicable to all devices using batteries, but for the sake of brevity, the following embodiments will be described taking electric vehicles as an example.

[0049] Figure 1A flowchart of a battery charging method for some embodiments of the present application. The battery charging method 100 can be applied to a battery, and further, can be applied to a BMS of the battery. The concept of the present application is described below by taking the method applied to a BMS of a battery as an example. The battery charging method comprises the following steps:

[0050] S101: obtaining an electrical parameter of the battery;

[0051] S102: determining whether the electrical parameter of the battery reaches a preset threshold value; wherein the preset threshold value is in a range satisfying the following condition: the SOC of the battery corresponding to the preset threshold value is 70-80%;

[0052] S103: when the electrical parameter of the battery reaches the preset threshold value, controlling to suspend charging the battery and controlling the battery to discharge for a time t;

[0053] S104: when the discharging ends, controlling to continue charging the battery.

[0054] In the embodiments of the present application, the electrical parameter of the battery includes SOC, voltage, charging step, and various parameters for representing the electrical state of the battery. The various electrical parameters can have a corresponding relationship, for example, the voltage of the battery at a first SOC is a first voltage, and the voltage of the battery at a second SOC is a second voltage, then the SOC corresponding to the first voltage is the first SOC, and the SOC corresponding to the second voltage is the second SOC. As for the charging step, it is mainly based on the node division given by the battery cell characteristics that needs to switch the charging rate, for example, charging from 0% SOC to 10% SOC at a certain rate C1, then 0-10% SOC is the first charging step in the charging step, and the SOC range corresponding to the first charging step is 0-10%. The embodiments of the present application can only select one electrical parameter as the electrical parameter that needs to be obtained in S101 in the entire charging process, and make the judgment of S102 based on the electrical parameter; or different electrical parameters can be selected as the electrical parameter that needs to be obtained in S101 in different stages of the charging process, and the judgment of S102 is made based on the electrical parameter, which will be described in detail later.

[0055] The voltage can be directly obtained by a voltage sensor or a voltage sampling chip. After obtaining the voltage of the battery, the other electrical parameter value corresponding to the voltage can be obtained through the above-mentioned corresponding relationship between the voltage and the other electrical parameter. For example, the corresponding relationship table between the above-mentioned electrical parameters can be pre-set in the BMS, and after the voltage is detected by the voltage sensor or the voltage sampling chip, the SOC or the charging step corresponding to the voltage is obtained by looking up the table. It can be understood that the voltage corresponding to the same SOC is different at different battery temperatures. Therefore, the temperature condition of the battery needs to be added to the above-mentioned corresponding relationship table to set the corresponding relationship table among SOC, temperature and voltage.

[0056] According to the foregoing, the timing of introducing discharging during the charging process is critical, and a suitable discharging time point needs to be set. In the embodiments of the present application, a preset threshold of the electrical parameter of the battery is set, and the time point of introducing discharging is taken as the time when the electrical parameter reaches the preset threshold. The value range of the preset threshold needs to meet: the SOC of the battery corresponding to the preset threshold is 70-80%. As described above, the fast-charging lithium precipitation dangerous SOC range is 70-80%, and when the battery is in this fast-charging lithium precipitation dangerous SOC state, timely introduction of discharging can achieve a better effect of reducing battery lithium precipitation on the basis of minimizing the impact on the charging time.

[0057] If the SOC is selected as the electrical parameter that needs to be obtained and judged, the value range of the SOC preset threshold is 70-80%; if the voltage is selected as the electrical parameter that needs to be obtained and judged, the value range of the voltage preset threshold is: the SOC of the battery corresponding to the voltage is 70-80%, that is, the value range of the voltage corresponding to the battery SOC in the range of 70-80%; if the charging step is selected as the electrical parameter that needs to be obtained and judged, the value range of the charging step preset threshold is: the SOC of the battery corresponding to the charging step is 70-80%, that is, the value range of the charging step corresponding to the battery SOC in the range of 70-80%. The above explanations can also be referred to when the value range of the preset threshold is mentioned below.

[0058] It can be understood that S101 is executed after the battery starts charging, and the electrical parameter of the battery can be obtained in a real-time uninterrupted manner, or in a manner of obtaining the electrical parameter once every interval preset time, or the start time of obtaining the electrical parameter of the battery can be set according to the preset threshold. For example, the electrical parameter is the SOC, and the preset threshold is 80%. A preset start time T can be set, T is the estimated time when the SOC reaches 80% in this charging process, and then the electrical parameter of the battery can be obtained at time T. In this way, compared with the manner of starting to obtain the SOC before time T, but the SOC at this time does not reach 80%, the above-mentioned manner can save system resources. Since the above-mentioned time T is only an estimated charging time, there can be a situation that the actual charging time when the SOC reaches 80% is earlier than T or later than T in the actual charging process. For the situation that the actual charging time when the SOC reaches 80% is later than T, it is also appropriate to set the start time of obtaining the electrical parameter as T, which is equivalent to obtaining the electrical parameter in advance. For the situation that the actual charging time when the SOC reaches 80% is earlier than T, the time of starting to obtain the electrical parameter of the battery can be correspondingly advanced. Therefore, in other embodiments, the electrical parameter of the battery can also be obtained at time (T-T1), where T1 can be the maximum floating difference of the actual charging time when the SOC reaches 80% calculated or statistically.

[0059] If the electrical parameter of the battery reaches the preset threshold, the BMS can control to suspend charging the battery and control to discharge the battery. In the embodiments of the present application, the discharge can be performed by using the existing circuit loop of the power consumption device or the battery. In this way, the discharge can be realized by using the circuit loop of the power consumption device itself without changing the electrical structure of the power consumption device and the charging device, thereby reducing the difficulty and cost of engineering application. For an electric vehicle, the discharge can be realized without changing the electrical structure of the vehicle or the charging pile. The discharge loop can be realized by the following ways, for example, discharging the battery pack to the thermal management system, discharging the battery pack to the balancing system, discharging the battery pack to the national power grid through the on-board charger (OBC), which can realize the discharge control by the BMS; the battery pack can also be discharged to the vehicle power consumption system (such as the air conditioning system), which needs the cooperation of the BMS and the vehicle to realize the discharge, for example, the BMS sends a discharge message to the vehicle, and the vehicle responds and starts the corresponding discharge system to discharge.

[0060] For the same loop, the current directions during charging and discharging are opposite. The charging in the embodiments of the present application refers to positive pulse charging, and the discharge can be realized by adding a small negative current pulse for a short time. The discharge current is generally less than 10 A, and the discharge time is set to a fixed time t, and the value range of t can be t≥3 s. Since lithium metal needs to be re-embedded, the discharge time is greater than or equal to 3 s, which can effectively ensure that the precipitated lithium metal is timely re-embedded into the positive electrode, thereby avoiding the continuous growth of lithium dendrites and finally causing safety problems. When the battery is discharged for t time, it represents the end of discharge, at which time the BMS can control to continue charging the battery until the charging is completed.

[0061] The technical scheme of the embodiments of the present application sets the preset threshold of the electrical parameter, suspends charging and discharges when the SOC of the battery reaches the preset threshold, can inhibit the continuous increase of lithium precipitation and the continuous growth of lithium dendrites by the lithium metal re-embedding into the positive electrode during the discharge process, improves the safety performance of the battery, and does not need to reduce the charging rate, thereby avoiding reducing the performance and user experience of the power consumption device; at the same time, the value range of the preset threshold meets: the state of charge SOC of the battery corresponding to the preset threshold is 70-80%, and the preset threshold selected in this range can achieve a better effect of reducing lithium precipitation of the battery.

[0062] As described above, considering the rule that the negative electrode potential of the battery with graphite as the negative electrode decreases with the increase of the SOC, and the high fast-charging capability of the lithium battery at low SOC, the discharge time point is selected at the fast-charging dangerous SOC 70-80% of the battery. In some embodiments of the present application, the negative electrode material of the battery includes graphite, and the electrical parameter is the SOC.

[0063] As mentioned earlier, commonly used cathode materials for lithium-ion batteries include lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, lithium iron phosphate, and ternary materials (such as lithium nickel cobalt manganese oxide). When using different cathode materials, the trends of the "time-SOC charging curve" (hereinafter referred to as the SOC curve) during battery charging are basically the same, with SOC gradually increasing with time. However, the "time-voltage charging curve" (hereinafter referred to as the voltage curve) differs depending on the cathode material. Figure 2 This is a schematic diagram of the voltage-charging curve of a battery using lithium iron phosphate as the cathode material during charging, as shown below. Figure 2 As shown, the voltage charging curve of a battery using lithium iron phosphate as the positive electrode material (hereinafter referred to as lithium iron phosphate battery) exhibits a rapid voltage increase at the beginning of charging (hereinafter referred to as the voltage jump stage); a stable voltage increase in the middle stage of charging (hereinafter referred to as the voltage stability stage); and a rapid voltage increase again at the end of charging (hereinafter referred to as the voltage jump stage). In contrast, for batteries using lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, or ternary materials as the positive electrode material, the voltage charging curve shows a more balanced upward trend throughout the charging process, with the voltage gradually increasing over time.

[0064] Because the voltage charging curve of a lithium iron phosphate battery includes a jump phase and a stable phase, if voltage is selected as the electrical parameter to be acquired, the voltage change is relatively small during the stable phase, making it impossible to accurately determine whether the battery's electrical parameters have reached a preset threshold. Therefore, in some embodiments, for lithium iron phosphate batteries, State of Charge (SOC) can be selected as the electrical parameter to be acquired. Discharge is initiated when the battery's SOC reaches a preset threshold. By selecting SOC as the electrical parameter to be acquired, the shortcomings of selecting voltage can be overcome, allowing for accurate determination of whether the battery's electrical parameters have reached the preset threshold. This can further reduce lithium plating and improve battery safety performance.

[0065] In some other embodiments, for the lithium iron phosphate battery, different electrical parameters are selected to determine whether the preset threshold is reached in different stages of the voltage charging curve during the charging process. For example, voltage is selected as the electrical parameter to be obtained in the voltage jump stage during the battery charging process, and SOC is selected as the electrical parameter to be obtained in the voltage stable stage. For example, when the battery SOC corresponding to the charging duration is within 0-20%, the period is in the voltage jump stage, and the electrical parameter is voltage; when the battery SOC corresponding to the charging duration is within 20-80%, the period is in the voltage stable stage, and the electrical parameter is SOC; when the battery SOC corresponding to the charging duration is greater than 80%, the period is in the voltage jump stage, and the electrical parameter is voltage. By the above method, voltage is used as the electrical parameter in the voltage jump stage during the battery charging, and SOC is used as the electrical parameter in the voltage stable stage instead of voltage with no large change amplitude, which can overcome the defect that the electrical parameter of the battery cannot be accurately determined by voltage in the voltage stable stage. The electrical parameter of the battery can be accurately determined whether the preset threshold is reached, which can further reduce the lithium precipitation of the battery and improve the safety performance of the battery.

[0066] Those skilled in the art should understand that the above technical solutions are not only used for lithium iron phosphate batteries, but also for other batteries as long as the voltage charging curve during the charging process includes a voltage jump stage and a voltage stable stage. That is, the electrical parameter is voltage in the voltage jump stage during the battery charging process, and the electrical parameter is SOC in the voltage stable stage during the battery charging process.

[0067] For batteries using lithium cobaltate, lithium manganate, lithium nickelate or ternary material as the positive electrode material, the SOC curve and the voltage curve have relatively balanced rising trends during the battery charging process, so the SOC can be selected as the electrical parameter to be obtained, the voltage can be selected as the electrical parameter to be obtained, or different electrical parameters can be selected in different stages, which is not limited by the present application.

[0068] It can be understood that the above preset threshold can be one or multiple. When the preset threshold is one, the electrical parameter of the battery will be discharged once when it reaches the preset threshold during the charging process. When the preset threshold is multiple, the electrical parameter of the battery will be discharged once when it reaches each preset threshold during the charging process, that is, S101 to S104 can be repeatedly executed multiple times to achieve multiple discharges and achieve better effect of inhibiting lithium precipitation of the battery.

[0069] In some embodiments, two preset threshold values can be set: a first preset threshold value and a second preset threshold value, the value range of the first preset threshold value satisfies the condition that the SOC corresponding to the first preset threshold value is 35-45%, and the value range of the second preset threshold value satisfies the condition that the SOC corresponding to the second preset threshold value is 70-80%. By adopting two different preset threshold values, the first discharge can be performed when the battery reaches the SOC state corresponding to the first preset threshold value, the lithium precipitation of the battery is reduced in the early charging stage, and selecting the preset threshold value for the first discharge in the range of 35-45% can achieve a better effect of reducing the lithium precipitation of the battery. The second discharge is performed when the battery reaches the SOC state corresponding to the second preset threshold value, the lithium precipitation of the battery is further reduced in the late charging stage, and selecting the preset threshold value for the second discharge in the range of 70-80% can achieve a better effect of reducing the lithium precipitation of the battery, thereby improving the safety performance of the battery. Among them, due to the fast charging demand, the battery has a large rate in the first 40% SOC, the negative electrode polarization potential decreases sharply, and the risk of lithium precipitation is slightly high. Therefore, 35-45% is selected as the value range of the first preset threshold value, which can ensure that the precipitated lithium metal is timely embedded into the positive electrode through the discharge process and avoid the accumulation of metal lithium. The principle and beneficial effects of setting the SOC corresponding to the second preset threshold value in the range of 70-80% have been described in detail in the foregoing, and will not be described here.

[0070] In some preferred embodiments, the SOC corresponding to the first preset threshold value is preferably 40%. Due to the fast charging demand, the battery has a large rate in the first 40% SOC, the negative electrode polarization potential decreases sharply, and the risk of lithium precipitation is slightly high. Selecting 40% as the SOC corresponding to the first preset threshold value can ensure that the precipitated lithium metal is timely embedded into the positive electrode through the discharge process and avoid the accumulation of metal lithium.

[0071] According to some preferred embodiments, different discharge times can be set according to the size of the reached preset threshold value. When a smaller preset threshold value is reached, the lithium precipitation is not too much, and the discharge time can be set slightly shorter. When a larger preset threshold value is reached, the lithium precipitation is relatively large, and the discharge time can be set longer than the discharge time when a smaller preset threshold value is reached. For example, the preset threshold values include a first preset threshold value and a second preset threshold value, the first preset threshold value is smaller than the second preset threshold value; when the electrical parameter of the battery reaches the first preset threshold value, the charging of the battery is controlled to be paused and the battery is controlled to be discharged for a time t1; when the electrical parameter of the battery reaches the second preset threshold value, the charging of the battery is controlled to be paused and the battery is controlled to be discharged for a time t2; wherein t1

[0072] S104 is executed at or after the end of the discharging. As to how to determine whether the discharging is ended, a discharging flag can be set to determine whether the discharging is ended. Figure 3 A flowchart of a charging method of a battery of some embodiments of the present application is shown in FIG. 3. In some embodiments, the method comprises the following steps: Figure 3

[0073] S301: obtaining an electrical parameter of the battery;

[0074] S302: determining whether the electrical parameter of the battery reaches a preset threshold; wherein the preset threshold is in a range satisfying the following condition: the SOC of the battery corresponding to the preset threshold is 70-80%;

[0075] S303: when the electrical parameter of the battery reaches the preset threshold, controlling to suspend charging the battery and controlling the battery to discharge for a time t;

[0076] S304: generating a first flag after the discharging for the time t;

[0077] S305: determining whether the first flag exists; if yes, performing S306; otherwise, performing S307;

[0078] S306: controlling to continue charging the battery and clearing the first flag;

[0079] S307: controlling to continue discharging the battery and performing S305.

[0080] By generating the first flag indicating that the discharging for the time t is completed after the discharging for the time t, when it is determined that the first flag exists, it is determined that the discharging is ended, the battery can be continued to be charged, and the first flag is cleared. This method is relatively simple and facilitates the implementation of the software control logic. In some other embodiments, the first flag can also be pre-configured as a parameter indicating whether the discharging for the time t is completed, and after the discharging for the time t, the value of the first flag is set to 1, when it is determined that the value of the first flag is 1, it is determined that the discharging is ended. This method is also relatively simple and facilitates the implementation of the software control logic.

[0081] The specific implementation process of S301-S303 is basically the same as that of S101-S103 in the foregoing embodiments, and the implementation process can be referred to the foregoing description. It can be understood that when the preset threshold is multiple, S401-S407 can also be repeatedly executed multiple times to realize multiple discharges.

[0082] ​After stopping charging, due to the BMS & charging pile control problem and other reasons in the actual working condition, the battery is overcharged and lithium is precipitated, or the actual charging condition is abnormal. If the input current of the charging pile is too large, the sampling temperature is abnormal, and the request current is abnormal, etc. will cause overcurrent lithium precipitation, so it is necessary to discharge again at this time, so that the lithium metal precipitated due to various reasons is timely embedded into the positive electrode under the action of negative pulse current, avoiding the growth of lithium metal and the safety problems caused thereby. Figure 4 The flowchart of the charging method of the battery of some embodiments of the present application is shown in FIG. 4, and the method 400 includes the following steps in some embodiments: Figure 4

[0083] S401: Obtain the electrical parameter of the battery;

[0084] S402: Determine whether the electrical parameter of the battery reaches a preset threshold value; wherein the value range of the preset threshold value satisfies the following condition: the SOC of the battery corresponding to the preset threshold value is 70-80%;

[0085] S403: When the electrical parameter of the battery reaches the preset threshold value, control to suspend charging the battery and control the battery to discharge for t time;

[0086] S404: When the discharging is completed, control to continue charging the battery;

[0087] S405: Determine whether the electrical parameter of the battery meets the stop charging condition;

[0088] S406: When the electrical parameter of the battery meets the stop charging condition, stop charging;

[0089] S407: Determine whether the electrical parameter of the battery reaches a preset threshold value; wherein the value range of the preset threshold value satisfies the following condition: the SOC of the battery corresponding to the preset threshold value is 70-80%;

[0090] S408: When the electrical parameter of the battery reaches the preset threshold value, control the battery to discharge for t time.

[0091] At this point, the BMS exits the charging control this time, and the charging is completed.

[0092] ​The stopping of charging includes various situations. For a regular charging process, a stopping condition of charging is generally set, for example, the stopping condition of charging is that the SOC reaches 100%, and the charging is stopped when the SOC reaches 100%. Of course, the stopping condition of charging can also be that the SOC reaches another preset value, for example, 80% or 60%, or the maximum voltage of the battery pack reaches a preset maximum value. If the connection between the power consumption device and the charging power supply is disconnected during the charging process, the charging is also stopped, for example, the charging line connected to the mobile phone is pulled off during the charging process of the mobile phone, or the charging plug connected to the power supply is pulled off, and the charging gun is pulled off during the charging process of the electric vehicle. These situations belong to the situation of stopping charging, and for these situations, the stopping condition of charging can be that the connection between the power consumption device using the battery and the charging power supply is disconnected.

[0093] When the electrical parameter of the battery meets the stopping condition of charging, the charging is stopped, and it is judged whether the electrical parameter of the battery reaches a preset threshold. When the electrical parameter of the battery reaches the preset threshold, the battery is controlled to discharge for a time t. The specific implementation process of S401 is basically the same as that of S101 in the foregoing embodiments, the specific implementation process of S402 and S407 is basically the same as that of S102 in the foregoing embodiments, the specific implementation process of S403 and S408 is basically the same as that of S103 in the foregoing embodiments, and the specific implementation process of S404 is basically the same as that of S104 in the foregoing embodiments. The difference lies in that S408 is executed after the charging is stopped, so that the “controlling to suspend charging the battery” in S103 does not need to be executed in S408, and the remaining implementation process can be referred to the foregoing description.

[0094] In some embodiments, when the electrical parameter of the battery meets the stopping condition of charging, a second flag bit can be generated, which is a parameter representing that the stopping condition of charging is reached. In S401, whether the electrical parameter of the battery meets the stopping condition of charging can be judged by judging whether the second flag bit exists. This mode is relatively simple and facilitates the specific implementation of the software control logic. In other embodiments, the second flag bit can also be pre-configured as a parameter representing that the stopping condition of charging is reached. When the electrical parameter of the battery meets the stopping condition of charging, the value of the second flag bit is set to 1. In S401, whether the electrical parameter of the battery meets the stopping condition of charging can be judged by judging whether the second flag bit is 1. This mode is also relatively simple and facilitates the specific implementation of the software control logic.

[0095] The above-mentioned mode judges whether the electrical parameter of the battery reaches a preset threshold again after the charging is stopped, and the preset threshold is selected in the range of 70-80% of the SOC corresponding to the preset threshold. If the preset threshold is reached, the battery is discharged. The battery can be discharged when it is necessary to reduce the lithium precipitation of the battery after the charging is stopped, and a better effect of reducing the lithium precipitation of the battery can be achieved.

[0096] The following takes electric vehicle charging as an example to illustrate the specific application process of the embodiments of the application:

[0097] 1. After the charging pile detects the gun insertion or card swiping, it judges whether the charging condition is met through message interaction between the charging pile and the BMS and charging state detection before charging;

[0098] 2. The charging pile judges that the charging condition is met, and sends the charging mode information to the BMS in the form of a current message; wherein, the charging mode includes a slow charging mode and a block charging mode;

[0099] 3. The BMS requests the current output corresponding to the charging mode from the charging pile according to the charging mode;

[0100] 3.1 In the slow charging mode: the BMS requests the current according to the current message, obtains the SOC information through the SOC module and sends it to the charging module in the BMS, the charging module judges whether the SOC reaches the SOC in Table 1, if it does, the BMS requests the current from the charging pile to be zero, and controls the preset discharge circuit to perform negative pulse discharge, the discharge time is the duration corresponding to the reached SOC in Table 1, after the discharge is completed, the charging module continues to request the current from the charging pile, if the SOC reaches the next preset threshold, the discharge continues until the charging stop condition is reached, and the charging is completed;

[0101] Table 1: SOC preset threshold and duration table introduced by negative pulse in slow charging process

[0102]

[0103] 3.2 In the fast charging mode (step constant current charging): the BMS requests the current from the charging pile by looking up the allowable current table (hereinafter referred to as allowable current table) under different SOC / charge rate / SOH (State of Health, degree of deterioration) as the requested current, and records the corresponding charging steps of the battery at different voltages. When the corresponding charging steps in Table 2 are reached, the current from the charging pile is requested to be zero, and the preset discharge circuit is controlled to perform negative pulse discharge, after the discharge is completed, the charging module continues to request the current from the charging pile according to the allowable current table; when the charging stop condition is reached and stabilized, the BMS requests the current from the charging pile to be zero, and judges whether the SOC reaches the SOC in Table 3, if it does, the BMS requests the current from the charging pile to be zero, and controls the preset discharge circuit to perform negative pulse discharge, the discharge time is the duration corresponding to the reached SOC in Table 2; after the discharge, the BMS exits the current charging control, and the charging is completed.

[0104] Table 2: Charging step preset threshold and duration table introduced by negative pulse in fast charging process

[0105]

[0106] Table 3 SOC preset threshold and duration table of negative pulse introduction at charging cut-off time in fast charging process

[0107]

[0108] The following is an experimental example:

[0109] Experimental Example 1:

[0110] A 100Ah lithium ion battery is used. A negative current of 3A is introduced at each current switching point in the original step charging strategy of the battery. The current duration is 3s. A total of 6 negative currents are introduced, and the total duration is 18s. The battery charging time and cycle life impact before and after the introduction of the negative current are shown in Table 4:

[0111] Table 4 Battery charging time and cycle life impact table before and after the introduction of negative current in experimental example 1

[0112]

[0113] As can be seen from Table 4, although the charging time is slightly extended, the extension is short and will not have a great impact on user experience, but the decline of the lithium ion battery is greatly reduced.

[0114] Experimental Example 2:

[0115] A 100Ah lithium ion battery is used. A negative current of 3A is introduced at 80% SOC and after stopping charging. The current duration is 3s each time. The battery charging time and cycle life impact before and after the introduction of the negative current are shown in Table 5:

[0116] Table 5 Battery charging time and cycle life impact table before and after the introduction of negative current in experimental example 2

[0117]

[0118] As can be seen from Table 5, although the charging time is slightly extended, the extension time is less than 10s, which has a small impact on user experience, but the decline of the lithium ion battery is greatly reduced.

[0119] In the foregoing, the charging method of the battery of the embodiments of the present application is described. Figures 1 to 4 The charging circuit of the battery of the embodiments of the present application will be described below. Figure 5 The parts not described in detail can be referred to the foregoing embodiments. Figure 5 The structure diagram of the charging circuit of the battery of some embodiments of the present application is shown in FIG. 5. Figure 5 As shown in FIG. 5, the charging circuit 500 of the battery includes a detection circuit 501, a control circuit 502 and a charging and discharging circuit 503. Wherein,

[0120] The detection circuit 501 is configured to acquire an electrical parameter of the battery.

[0121] The control circuit 502 is configured to: determine whether the electrical parameter of the battery reaches a preset threshold according to the electrical parameter of the battery acquired by the detection circuit 501; wherein the preset threshold has a value range satisfying the following condition: a state of charge (SOC) corresponding to the preset threshold is 70-80%; when the electrical parameter of the battery reaches the preset threshold, the control circuit 502 controls the charge-discharge circuit 503 to suspend charging the battery and controls the charge-discharge circuit 503 to discharge the battery for a time t; and when the discharging ends, the control circuit 502 controls the charge-discharge circuit 503 to continue charging the battery.

[0122] The technical scheme of the embodiment of the application can suspend charging and discharge when the SOC of the battery reaches the preset threshold by setting the preset threshold of the electrical parameter, thereby reducing lithium precipitation of the battery, improving the safety performance of the battery, and avoiding reducing the performance and user experience of the power consumption device without reducing the charging rate; meanwhile, the preset threshold has a value range satisfying the condition that the SOC of the battery corresponding to the preset threshold is 70-80%, and selecting the preset threshold in the range can achieve a better effect of reducing lithium precipitation of the battery on the basis of reducing the influence on the charging time as much as possible.

[0123] In some embodiments, the positive electrode material of the battery is lithium iron phosphate, and the electrical parameter is the SOC.

[0124] In some embodiments, the positive electrode material of the battery is lithium iron phosphate, the electrical parameter is the voltage in the voltage jump stage of the battery during charging, and the electrical parameter is the SOC in the voltage stable stage of the battery during charging.

[0125] In some embodiments, the preset threshold includes a first preset threshold and a second preset threshold, the first preset threshold has a value range satisfying the condition that the SOC corresponding to the first preset threshold is 35-45%, and the second preset threshold has a value range satisfying the condition that the SOC corresponding to the second preset threshold is 70-80%.

[0126] In some embodiments, the preset threshold includes a first preset threshold and a second preset threshold, the first preset threshold is smaller than the second preset threshold; and the control circuit 502 is further configured to: when the electrical parameter of the battery reaches the preset threshold, controlling to suspend charging the battery and discharging the battery for a time t includes: when the electrical parameter of the battery reaches the first preset threshold, controlling to suspend charging the battery and discharging the battery for a time t1; and when the electrical parameter of the battery reaches the second preset threshold, controlling to suspend charging the battery and discharging the battery for a time t2; wherein t1

[0127] In some embodiments, the control circuit 502 is further configured to: determine whether the electrical parameter of the battery meets a stop charging condition; stop charging when the electrical parameter of the battery meets the stop charging condition; and determine whether the electrical parameter of the battery reaches a preset threshold value; wherein the preset threshold value is in a range satisfying the following condition: the SOC corresponding to the preset threshold value is 70-80%; and control the battery to discharge for a time t when the electrical parameter of the battery reaches the preset threshold value.

[0128] The battery management system according to some embodiments of the present application will be described below in combination with Figure 6 The charging controller of the battery according to some embodiments of the present application will be described below in combination with Figure 6 The charging controller of the battery according to some embodiments of the present application will be described below in combination with Figure 6 As shown in FIG. 6, the charging controller 600 of the battery includes one or more processors 601 working individually or collectively, which are configured to execute the steps of the charging method of the battery in the above embodiments.

[0129] The technical solution of the battery management system according to some embodiments of the present application can pause charging and discharge when the SOC of the battery reaches the preset threshold value, thereby reducing lithium precipitation of the battery, improving the safety performance of the battery, and avoiding reducing the performance and user experience of the power consumption device without reducing the charging rate. Meanwhile, the preset threshold value is in a range satisfying the following condition: the SOC corresponding to the preset threshold value is 70-80%, and selecting the preset threshold value in the range can achieve a better effect of reducing lithium precipitation of the battery on the basis of reducing the charging time as much as possible.

[0130] The battery management system according to some embodiments of the present application will be described below in combination with Figure 7 The battery management system according to some embodiments of the present application will be described below in combination with Figure 7 The battery management system according to some embodiments of the present application will be described below in combination with Figure 7 As shown in FIG. 7, the battery management system 700 includes at least one processor 701 and a memory 702 communicatively connected to the at least one processor 701; wherein the memory 702 stores instructions executable by the at least one processor 701, and the instructions are executed by the at least one processor 701 to enable the at least one processor 701 to implement the steps of the charging method of the battery in any of the above embodiments.

[0131] The technical solution of this application embodiment, by setting a preset threshold for electrical parameters, pauses charging and discharges when the battery's SOC reaches the preset threshold. This promotes the re-intercalation of deposited lithium into the positive electrode, avoids the accumulation of lithium metal deposits and the continuous growth of dendrites, and improves the battery's safety performance. Furthermore, it does not require reducing the charging rate, thus avoiding a decrease in the performance of the electrical device and the user experience. At the same time, the value range of the preset threshold satisfies the following: the SOC of the battery corresponding to the preset threshold is 70-80%. Selecting the preset threshold within this range can achieve a better effect of reducing lithium deposition in the battery while minimizing the impact on charging time.

[0132] The following will combine Figure 8 and Figure 9 The battery described in this application has been modified to include parts not described in detail in the foregoing embodiments. Figure 8 This is a schematic diagram of the battery structure according to some embodiments of this application, such as... Figure 8 As shown, the battery 800 includes a charging controller 600 for the battery as described in the above embodiment. Figure 9 This is a schematic diagram of the battery structure according to some embodiments of this application, such as... Figure 9 As shown, the battery 900 includes the battery management system 700 as described in the above embodiment.

[0133] The technical solution of this application embodiment, by setting a preset threshold for electrical parameters, pauses charging and discharges when the battery's SOC reaches the preset threshold. This reduces lithium plating in the battery, improves battery safety performance, and avoids reducing the charging rate, thus preventing a decrease in the performance of the electrical device and the user experience. At the same time, the preset threshold value range satisfies the following: the SOC of the battery corresponding to the preset threshold is 70-80%. Selecting the preset threshold within this range can achieve a better effect of reducing lithium plating in the battery while minimizing the impact on charging time.

[0134] The following will combine Figure 10 The electrical apparatus described in this application refers to the foregoing embodiments, wherein parts not described in detail may be referred to the foregoing embodiments. Figure 10 This is a schematic diagram of the structure of an electrical device according to some embodiments of this application, such as... Figure 10 As shown, the electrical device 1000 includes a battery 800 or a battery 900 as described in the above embodiment.

[0135] The technical scheme of the embodiments of the present application sets the preset threshold of the electrical parameter, suspends charging and discharges when the SOC of the battery reaches the preset threshold, can reduce lithium precipitation of the battery, improve the safety performance of the battery, and does not need to reduce the charging rate, thereby avoiding reducing the performance and user experience of the electric device; meanwhile, the value range of the preset threshold meets: the state of charge SOC of the battery corresponding to the preset threshold is 70-80%, and selecting the preset threshold in the range can achieve a better effect of reducing lithium precipitation of the battery on the basis of as low as possible reducing the influence on the charging time.

[0136] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features, but these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method of charging a lithium iron phosphate battery, characterized by, The method comprises: determining, according to a state of charge (SOC) of the battery, whether a charging period of the battery is a voltage jump phase or a voltage stable phase; when the SOC corresponding to the charging period is lower than 20% or higher than 80%, the charging period is the voltage jump phase; when the SOC corresponding to the charging period is within 20-80%, the charging period is the voltage stable phase; if the charging period is the voltage jump phase, using voltage as an electrical parameter; if the charging period is the voltage stable phase, using SOC as the electrical parameter, and obtaining the SOC of the battery by querying a pre-set correspondence table among SOC, temperature and voltage based on the voltage and temperature of the battery; determining whether the electrical parameter of the battery reaches a preset threshold; the preset threshold comprises one or more preset thresholds, and at least one preset threshold corresponds to an SOC of 70-80%; when the electrical parameter of the battery reaches the preset threshold, controlling to suspend charging the battery and control the battery to discharge for t time, wherein t≥3s; when the discharging ends, controlling to continue charging the battery.

2. The method of claim 1, wherein, The negative electrode material of the battery comprises graphite.

3. The method of claim 1, wherein, The preset threshold comprises a first preset threshold and a second preset threshold, the value range of the first preset threshold satisfies the following condition: the SOC corresponding to the first preset threshold is 35-45%, and the value range of the second preset threshold satisfies the following condition: the SOC corresponding to the second preset threshold is 70-80%.

4. The method of any one of claims 1 to 3, wherein, The preset threshold comprises a first preset threshold and a second preset threshold, the first preset threshold is smaller than the second preset threshold. The when the electrical parameter of the battery reaches the preset threshold, controlling to suspend charging the battery and control the battery to discharge for t time comprises: when the electrical parameter of the battery reaches the first preset threshold, controlling to suspend charging the battery and control the battery to discharge for t1 time; when the electrical parameter of the battery reaches the second preset threshold, controlling to suspend charging the battery and control the battery to discharge for t2 time; wherein t1 5. A charge controller for a lithium iron phosphate battery, characterized by, The method comprises: one or more processors, which work individually or jointly, and are used to execute the steps of the charging method of the lithium iron phosphate battery as claimed in any one of claims 1 to 4.

6. A lithium iron phosphate battery management system characterized by, The method comprises: at least one processor; and a memory connected in communication with the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to implement the steps of the charging method of the lithium iron phosphate battery as claimed in any one of claims 1 to 4.

7. A lithium iron phosphate battery, characterized by, The method comprises: the charging controller of the lithium iron phosphate battery as claimed in claim 5, or the lithium iron phosphate battery management system as claimed in claim 6.

8. An electrical device, characterized by The lithium iron phosphate battery as claimed in claim 7 is used to provide electric energy.

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