Charging method for battery in low-temperature state, battery, electric device, and charging device

Abstract

The present application relates to the technical field of batteries, and provides a charging method for a battery in a low-temperature state, a battery, an electric device, and a charging device. The charging method comprises: determining a state of charge of a current battery, obtaining a first initial state of charge of the current battery, discharging the current battery for temperature recovery, and obtaining a first intermediate state of charge of the current battery after discharging, and a first discharging duration; and performing charging and energy replenishment on the current battery, wherein by using the first intermediate state of charge as a charging starting point, the current battery is charged under a certain charging condition until a preset final state of charge of the current battery is reached, a required charging duration is a first charging duration, and a charging duration of the current battery is the sum of the first discharging duration and the first charging duration. The charging method of the present application is applicable to charging a battery in a low-temperature state, and can reduce the probability of lithium precipitation in the battery and shorten the charging duration.

Description

Charging method for battery in low-temperature state, battery, electric device and charging device

[0001] The present application claims priority from the Chinese patent application No. 202410964688.9 filed on July 18, 2024 in the State Intellectual Property Office, and entitled "Charging method for battery in low-temperature state, battery, electric device and charging device", the whole content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the technical field of battery, and particularly provides a charging method for battery in low-temperature state, battery, electric device and charging device. BACKGROUND

[0003] With the continuous maturity and development of new energy technology, new energy vehicles are also more and more favored by everyone. Among them, the power battery as the core component of the new energy vehicle plays an important role.

[0004] However, the power battery is sensitive to temperature, and its charging performance is greatly reduced in a low-temperature state. Especially under low-temperature conditions, if high charging rate is used for charging, the power battery is prone to lithium precipitation, thereby affecting the service life of the power battery, and also greatly increasing the charging time of the power battery in a low-temperature state. TECHNICAL PROBLEM

[0005] The present application aims to provide a charging method for battery in low-temperature state, battery, electric device and charging device, and aims to solve the problem of long charging time of the existing battery in a low-temperature state. TECHNICAL SOLUTION

[0006] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is:

[0007] In a first aspect, the present application provides a charging method for battery in low-temperature state, which comprises:

[0008] determining the state of charge of the current battery, obtaining the first initial state of charge of the current battery, discharging the current battery to restore temperature, and obtaining the first intermediate state of charge and the first discharging time of the current battery after discharging;

[0009] charging the current battery, the first intermediate state of charge of the current battery being used as the charging starting point, and charging under certain charging conditions to the preset terminal state of charge of the current battery, the required charging time being the first charging time; the charging time of the current battery being the sum of the first discharging time and the first charging time.

[0010] The application provides a charging method for a battery in a low-temperature state, which is used for improving the charging rate of the battery in the low-temperature state. When the battery is charged, especially when the battery is charged at a large rate, lithium precipitation is prone to occur in the battery, thereby affecting the service life of the battery. The charging method provided by the application can improve the lithium precipitation problem of the battery during the charging process and improve the charging rate of the battery in the low-temperature state. Specifically, in the initial state before the battery is charged, the state of charge of the current battery is first confirmed. Here, the state of charge refers to the remaining capacity of the current battery. Since the battery itself is in a low-temperature condition, the battery itself can be warmed up by discharging first to reduce lithium precipitation during direct charging. After the current battery is discharged for a period of time, the first intermediate state of charge and the first discharging time of the current battery after discharging are obtained. The current battery is charged, the first intermediate state of charge is used as the charging starting position of the current battery, and the current battery is charged to a preset terminal state of charge under certain charging conditions. The required charging time is the first charging time. The charging time of the current battery is the sum of the first discharging time and the first charging time. The charging method provided by the application is suitable for charging the battery in a low-temperature state and can reduce the probability of lithium precipitation of the battery and shorten the charging time.

[0011] In some embodiments, in the step of determining the state of charge of the current battery, the current battery is discharged and warmed up at a preset discharging rate.

[0012] By adopting the above technical solution, the discharging time of the battery can be adjusted by the preset discharging rate. Generally, the probability of lithium precipitation of the battery in a low-temperature state is low when the battery is discharged at a large rate.

[0013] In some embodiments, the preset discharging rate includes a constant discharging rate, a linear discharging rate and a nonlinear discharging rate.

[0014] By adopting the above technical solution, the battery can be discharged and heated according to the initial state of charge of the current battery and different discharging and heating requirements.

[0015] In some embodiments, in the step of determining the state of charge of the current battery, the current battery is discharged and warmed up to a rated temperature, and the second intermediate state of charge and the second discharging time of the current battery corresponding to the rated temperature are obtained.

[0016] The current battery is charged, the second intermediate state of charge is used as the charging starting position of the current battery, and the current battery is charged to a preset terminal state of charge under the same charging condition. The required charging time is the second charging time.

[0017] The charging duration of the current battery is the sum of the second discharging duration and the second charging duration.

[0018] By adopting the technical scheme, the second intermediate state of charge of the battery is determined by the rated temperature, that is, when the temperature of the battery is the rated temperature, the battery is not suitable for continuing discharging for temperature recovery, and there is a probability of affecting the charging duration of the battery in the charging mode of discharging first and then charging.

[0019] In some embodiments, after the step of determining the state of charge of the current battery, the charging method further comprises:

[0020] The current battery is charged, and the second initial state of charge and the third charging duration of the current battery are obtained, the second initial state of charge is taken as the discharging starting point of the current battery, and the third intermediate state of charge and the third discharging duration of the current battery after re-discharging are obtained again; the current battery takes the third intermediate state of charge as the charging starting point, and is charged to the preset terminal state of charge under the same charging condition, and the required charging duration is the fourth charging duration.

[0021] The charging duration of the current battery is the sum of the third charging duration, the first discharging duration, the third discharging duration and the fourth discharging duration.

[0022] By adopting the technical scheme, the initial state of charge of the battery in this scenario is low, and after discharging for temperature recovery, the battery still has a high probability of lithium precipitation, therefore, the battery is charged in the mode of multiple discharging and multiple charging combination to improve the corresponding lithium precipitation phenomenon, and the corresponding fast charging demand can be met.

[0023] In some embodiments, before the step of charging the current battery, the charging method further comprises:

[0024] It is judged whether the current battery is involved in a direct charging mode, the initial temperature of the current battery is obtained, and the initial temperature is compared with a preset temperature, and when the initial temperature of the current battery is higher than the preset temperature, the current battery is switched to the direct charging mode.

[0025] By adopting the technical scheme, the preset temperature is the critical temperature for determining whether the battery is in a low-temperature state for direct charging, that is, when the initial temperature of the battery is greater than the preset temperature, the battery is directly charged, and the lithium precipitation phenomenon is less likely to occur.

[0026] In some embodiments, in the step of determining the state of charge of the current battery, the battery is discharged for temperature recovery, and when the temperature after recovery is greater than the preset temperature, the current battery is switched to the direct charging mode.

[0027] By adopting the technical scheme, when the battery is discharging for temperature recovery, the temperature of the battery can be monitored in real time, and when the temperature of the battery for temperature recovery is greater than the preset temperature, the battery can stop discharging and directly perform normal charging, and the phenomenon of lithium precipitation of the battery is greatly reduced.

[0028] In some embodiments, in the step of determining the state of charge of the current battery, the charging method further comprises:

[0029] The current battery is simulated to perform charging to a preset terminal state of charge of the battery with the first initial state of charge as a charging starting point, and a fourth charging duration is obtained.

[0030] When the fourth charging duration is greater than the sum of the first discharging duration and the first charging duration, the current battery directly performs charging without performing a discharging and temperature recovery action.

[0031] By adopting the technical scheme, the charging total duration of directly charging the current battery is shorter in the case of a high first initial state of charge.

[0032] In a second aspect, the embodiments of the present application provide a battery, comprising a plurality of battery monomers and a battery management device for controlling each battery monomer, and the battery management device is configured to execute the charging method in the low-temperature state of the battery.

[0033] The battery provided by the present application is used to execute the charging method in the low-temperature state of the battery during the charging process, so that each battery monomer can be charged in the low-temperature state, and the probability of lithium precipitation of the battery can be reduced on the basis of shortening the charging duration.

[0034] In a third aspect, the embodiments of the present application provide a power consumption device, comprising a battery and a control module electrically connected to the battery, and the control module is configured to execute the charging method in the low-temperature state of the battery.

[0035] The power consumption device provided by the present application is used to execute the charging method in the low-temperature state of the battery during the charging process, so that the battery in the power consumption device can be charged in the low-temperature state, and the probability of lithium precipitation of the battery can be reduced on the basis of shortening the charging duration.

[0036] In a fourth aspect, the embodiments of the present application provide a charging device, comprising a charging end and a control end electrically connected to the charging end, and the control end is configured to execute the charging method in the low-temperature state of the battery.

[0037] The beneficial effects of this application are as follows: When charging the battery and the electrical device, the control terminal of the charging device provided by this application is used to execute the charging method of the battery under low temperature conditions. When the battery and the electrical device are electrically connected to the charging terminal, the device is used to charge the battery and the electrical device under low temperature conditions. In addition to shortening the charging time, it can also reduce the probability of lithium plating in the battery. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 is a flowchart of a battery charging method at low temperatures provided in an embodiment of this application;

[0040] Figure 2 is an exploded view of the battery provided in an embodiment of this application;

[0041] Figure 3 is a schematic diagram of the structure of the electrical equipment provided in the embodiment of this application;

[0042] Figure 4 is a schematic diagram of the structure of the charging device provided in the embodiment of this application.

[0043] In the figure, the following labels are used: 100, battery; 10, battery cell; 20, battery management device; 1000, electrical equipment; 1001, control module; 2000, charging equipment; 2001, charging terminal; 2002, control terminal.

[0044] Implementation methods of this application

[0045] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0046] In the description of this application, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0047] In addition, the terms "first", "second", "third", etc. are used only for descriptive purposes and are not to be construed as indicating or implying relative importance or an ordered ranking of the indicated technical features. Thus, features defined with "first", "second" or "third" can explicitly or implicitly include one or more of such features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically defined.

[0048] In the present application, unless otherwise explicitly and specifically defined, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above-mentioned terms in the present application can be understood according to the specific circumstances.

[0049] With the continuous maturity and development of new energy technology, new energy vehicles are also more and more popular. Among them, the power battery as the core component of new energy vehicles plays an important role.

[0050] However, in high-altitude areas or winter, the power battery is affected by the environment temperature, and is often at a relatively low temperature during charging. With the current charging technology, the charging rate of the battery at low temperature is relatively small, which can greatly increase the overall charging time.

[0051] The current improvement method is to charge the battery in a low temperature state at a high charging rate, which often causes serious lithium precipitation in the battery, affecting the service life of the battery.

[0052] Therefore, the present application provides a charging method for a battery in a low temperature state, which mainly adopts the method of discharging and warming up first and then charging to improve the working temperature of the battery. The charging time is the sum of the first discharging time and the first charging time. In this way, on the basis of shortening the charging time, the probability of lithium precipitation in the battery during charging can also be reduced.

[0053] Please refer to FIG. 1, the present application embodiment provides a charging method for a battery in a low temperature state, comprising:

[0054] S001, determine the state of charge of the current battery, obtain the first initial state of charge of the current battery, discharge and warm up the current battery, and obtain the first intermediate state of charge and the first discharging time of the current battery after discharging.

[0055] It can be understood that the state of charge of the battery is used to reflect the remaining capacity of the battery, which is defined as the ratio of the remaining capacity to the battery capacity in value, and can be expressed by SOC (State of Charge).

[0056] The first initial state of charge is the initial remaining capacity of the current battery, for example, the first initial state of charge of the battery can be 30%, 40%, 50%, 60%, etc.

[0057] Discharging the current battery to restore temperature means that the temperature of the battery will rise during discharging. Here, battery discharging can refer to being used to discharge, or charging the charging device, for example, when the new energy vehicle is charging at the charging pile, the battery of the new energy vehicle discharges, which means that the battery of the new energy vehicle charges the energy storage device of the charging pile.

[0058] The charging process and discharging process of the battery will both cause temperature rise, but when the battery is charged and discharged at the same rate, it is found that the temperature rise of discharging is greater than that of charging, that is, discharging can achieve rapid heating of the battery in a short time, thereby improving the working temperature of the battery to be charged.

[0059] After discharging, the state of charge of the battery will decrease, that is, from the first initial state of charge to the first intermediate state of charge, for example, the initial remaining capacity of the battery is 30%, and after discharging to restore temperature, the remaining capacity is 15%, which is the first intermediate state of charge.

[0060] The first discharging duration refers to the time for the battery to discharge from the first initial state of charge to the first intermediate state of charge. Since the battery needs to be charged, the first discharging duration should be recorded for calculating the total charging time duration of the current battery.

[0061] S002, charging the current battery, the current battery takes the first intermediate state of charge as the charging starting position, and charges under certain charging conditions to the preset terminal state of charge of the current battery, and the required charging time is the first charging time.

[0062] It can be understood that the charging time duration of the battery discharging first and then charging should be the sum of the first discharging duration and the first charging duration, and the charging mode is discharging first and then charging, compared with the first initial state of charge as the charging starting position, that is, the battery belongs to the conventional charging mode.

[0063] In order to maintain the comparability of the two charging modes, the charging conditions are the same, for example, the same charging rate, which can be a constant charging rate or a dynamic fluctuation nonlinear charging rate.

[0064] The preset end-of-charge state refers to the predicted state of charge after the battery is charged, for example, the remaining battery capacity of the battery is charged from 30% to 97%, and then the battery capacity of 97% is the preset end-of-charge state of the battery.

[0065] Since the discharge rate of the battery is not affected by temperature and state of charge, or is less affected by temperature and state of charge, and the battery discharge process is difficult to cause lithium precipitation, the first discharge time can be shortened by high-rate discharge, and after the battery is discharged to restore the temperature, the battery can be charged at a higher charging rate, so the first charging time can be adjusted, and therefore the sum of the first charging time and the first discharge time can be less than the time when the battery is charged in the conventional charging mode.

[0066] That is, when the sum of the first charging time and the first discharge time is less than the time when the battery is charged in the conventional charging mode, the charging mode of discharging first and then charging can be performed on the current battery.

[0067] For example, when a new energy vehicle is charging at a charging pile, the initial battery capacity of the new energy vehicle is obtained, and the charging mode of the new energy vehicle is selected according to the user-set end-of-charge capacity of the battery, i.e., the preset end-of-charge state.

[0068] First, the first initial state of charge of the battery of the new energy vehicle can be collected by the charging pile, or the first initial state of charge of the battery can be calculated by the control part of the new energy vehicle, for example, the first initial state of charge of the battery is 30% at this time, the battery is discharged to restore the temperature at a certain discharge rate to obtain a first intermediate state of charge and a first discharge time, for example, the first intermediate state of charge is 15%, and the first discharge time is the time when the battery is discharged from the first initial state of charge to the first intermediate state of charge at a certain discharge rate, for example, the battery is discharged from 30% to 15% at a discharge rate of 1C, and the time length is T1;

[0069] Secondly, the charging pile can test the time length of two charging modes according to the same charging rate, or the control device of the new energy vehicle can also simulate the first intermediate state of charge at the same charging rate, one of the charging modes is to take the first intermediate state of charge 15% as a new charging starting point and take the preset end-of-charge state 97% as a charging termination point, and the whole process takes a time length of first charging time T2, and the other charging mode is to directly take the first initial state of charge 30% as a charging starting point and take the preset end-of-charge state 97% as a charging termination point, and the whole process takes a time length of charging time T3, then the charging time of the charging mode of discharging first and then charging is T1+T2, and the charging time of the direct charging mode is T3;

[0070] Finally, the charging time of the above two charging modes is compared through the control end of the charging pile or the control device of the new energy vehicle, and T1+T2 should be less than T3.

[0071] The battery charging method in the low-temperature state provided by the application is used to improve the charging rate of the battery in the low-temperature state. When the battery is charged in the low-temperature state, especially when it is charged at a large rate, lithium precipitation is prone to occur in the battery, which affects the service life of the battery. The charging method provided by the application can improve the lithium precipitation problem of the battery during charging and improve the charging rate of the battery in the low-temperature state. Specifically, in the initial state before the battery is charged, the state of charge of the current battery is first confirmed. Here, the state of charge refers to the remaining capacity of the current battery. Since the battery itself is in a low-temperature condition, the battery itself can be warmed up by discharging first to reduce lithium precipitation during direct charging. In addition, after the current battery is discharged for a period of time, the first intermediate state of charge of the current battery after discharging and the first discharging time are obtained. The current battery is charged to supplement the power, and the first intermediate state of charge of the current battery is used as the starting position of charging. The battery is charged to a preset terminal state of charge under certain charging conditions, and the required charging time is the first charging time. The charging time of the current battery is the sum of the first discharging time and the first charging time. The charging method provided by the application is suitable for charging the battery in the low-temperature state, and can reduce the probability of lithium precipitation of the battery and shorten the charging time.

[0072] In some embodiments, in the step of determining the state of charge of the current battery, the current battery is discharged at a preset discharging rate for temperature recovery.

[0073] It can be understood that the discharging rate of the battery has little or no effect on lithium precipitation of the battery during discharging. Therefore, the discharging rate of the battery can be adjusted according to actual use requirements, for example, the battery can be discharged at a discharging rate of 0.5C, 1C, 1.5C, 2C, 2.5C and 3C.

[0074] Here, C represents the rated capacity of the battery. Specifically, 1C discharging rate means that it takes 1 hour to discharge the rated capacity current of the battery completely.

[0075] Therefore, the discharging process of the battery is less affected by temperature or almost not affected by temperature, and the discharging rate can be adjusted according to the corresponding discharging time requirement.

[0076] In this way, the discharging time of the battery can be adjusted by the preset discharging rate. Generally, the probability of lithium precipitation of the battery in the low-temperature state is low when it is discharged at a large rate.

[0077] In some embodiments, the preset discharging rate includes a constant discharging rate, a linear discharging rate and a nonlinear discharging rate.

[0078] It can be understood that the constant discharge rate refers to that the discharge rate of the battery is fixed during the entire discharge process; the linear discharge rate refers to that the discharge rate of the battery is linearly increased or decreased during the entire discharge process; and the nonlinear discharge rate refers to that the discharge rate of the battery is nonlinearly changed in real time during the entire discharge process.

[0079] In this way, the battery can be discharged according to the initial state of charge of the current battery and different discharge heating requirements.

[0080] In some embodiments, in the step of determining the state of charge of the current battery, the current battery is discharged to recover temperature to a rated temperature, and the second intermediate state of charge corresponding to the rated temperature and a second discharge duration of the current battery are obtained;

[0081] The current battery is charged to recover energy, the second intermediate state of charge is used as a charging starting point, and the current battery is charged to a preset terminal state of charge under the same charging condition, and the required charging duration is a second charging duration;

[0082] The charging duration of the current battery is the sum of the second discharge duration and the second charging duration.

[0083] It can be understood that the temperature of the battery is continuously increased during the continuous discharge temperature recovery process. Generally, a temperature protection mechanism is provided in the battery to adjust the working temperature of the battery. The rated temperature of the battery refers to the critical working temperature of the battery under the corresponding rated current or rated voltage. That is, the working temperature of the battery will exceed the rated temperature during continuous discharge heating. However, the charging duration is also continuously accumulated and increased, thereby prolonging the total charging time. Therefore, the rated temperature also corresponds to the second intermediate state of charge.

[0084] The second intermediate state of charge is the current remaining capacity of the battery after the battery is discharged to recover temperature to the rated temperature.

[0085] In the comparison of the two charging modes, the second intermediate state of charge and the first initial state of charge are used as the charging starting points, and the current battery is charged to the preset terminal state of charge under the same charging condition, thereby obtaining the second charging duration and the direct charging duration.

[0086] Since the battery discharge process does not cause lithium precipitation or has a relatively low probability of causing lithium precipitation, the sum of the second charging duration and the second discharge duration is likely to be significantly less than the direct charging duration. Thus, a better charging scheme of the battery under a low-temperature state can be obtained, that is, the total time is shorter under this charging mode.

[0087] Thus, the second intermediate state of charge of the battery can be determined by the rated temperature, that is, when the temperature of the battery is the rated temperature, the battery is not suitable for continuing to discharge and warm up, and there is a probability that the charging time of the battery in the charging mode of discharging first and then charging will be affected.

[0088] In some embodiments, after the step of determining the state of charge of the current battery, the charging method further comprises:

[0089] The current battery is charged with power supplement, and the second initial state of charge and the third charging time of the current battery are obtained, the second initial state of charge is taken as the discharge starting point of the current battery, and the third intermediate state of charge and the third discharge time of the current battery after re-discharge are obtained again; the current battery takes the third intermediate state of charge as the charging starting point, and is charged to the preset terminal state of charge under the same charging condition, and the required charging time is the fourth charging time;

[0090] The charging time of the current battery is the sum of the third charging time, the first discharge time, the third discharge time and the fourth discharge time.

[0091] It can be understood that when the initial state of charge of the battery is low, and the working temperature of the battery is still difficult to reach the required temperature after discharging and warming up, one charging power supplement can be selected after one discharging and warming up of the battery, the supplemented power is discharged and warmed up again, and finally, the second charging power supplement is performed to the preset terminal state of charge. Of course, the charging power supplement and discharging and warming up in the intermediate process can be performed multiple times according to actual charging demand.

[0092] Therefore, in this scenario, the sum of the third charging time, the first discharge time, the third discharge time and the fourth discharge time can be less than the direct charging time, and the current battery can adopt the charging mode of discharging first, then charging, then discharging, and then charging.

[0093] In this way, the scenario is used for the initial state of charge of the battery being low, and the battery still has a high probability of lithium precipitation after discharging and warming up, therefore, the battery is charged in the mode of multiple discharges and multiple charges of the combination of discharging and charging, so as to improve the corresponding lithium precipitation phenomenon, and at the same time, the corresponding fast charging demand can be met.

[0094] In some embodiments, before the step of charging the current battery with power supplement, the charging method further comprises:

[0095] It is determined whether the current battery is involved in the direct charging mode, the initial temperature of the current battery is obtained, and compared with the preset temperature, when the initial temperature of the current battery is higher than the preset temperature, the current battery enters the direct charging mode.

[0096] It can be understood that the initial temperature of the current battery determines whether the battery is charged directly, because when the initial temperature of the battery is higher than the preset temperature, it is considered that the battery needs to be directly charged, and the lithium precipitation phenomenon is less likely to occur.

[0097] For example, the preset temperature of the battery can be set to 5°C, and when the initial temperature of the battery is higher than 5°C, the battery can be directly charged, so that 5°C is the critical temperature of whether the current battery is in a low temperature state.

[0098] The initial temperature of the battery can be detected by a temperature measuring device provided by the battery, collected by a temperature monitoring device of the electrical equipment, or obtained by interaction between the charging end of the charging device and the battery management module of the battery.

[0099] Therefore, the preset temperature is the critical temperature for determining whether the battery is directly charged in a low temperature state, that is, when the initial temperature of the battery is greater than the preset temperature, the battery is directly charged, and the lithium precipitation phenomenon is less likely to occur.

[0100] In some embodiments, in the step of determining the state of charge of the current battery, the battery is discharged to restore the temperature, and when the temperature after temperature restoration is greater than the preset temperature, the current battery enters the direct charging mode.

[0101] It can be understood that when the temperature after temperature restoration of the current battery is greater than the preset temperature, the battery can enter the direct charging mode at the current temperature, and at this time, the probability of lithium precipitation is also relatively low, and the overall charging time can also be shortened.

[0102] This scenario is suitable for the case where the initial state of charge of the battery is high, and the battery is discharged to restore the temperature to any intermediate state of charge lower than the initial state of charge, and the current any intermediate state of charge is used as the charging starting point for charging. The overall charging time is higher than that of charging with the initial state of charge as the charging starting point. For example, when the initial state of charge of the current battery is higher than 50%, the above charging mode can be used.

[0103] Therefore, when the battery is discharged to restore the temperature, the temperature of the battery can be monitored in real time, and when the temperature after temperature restoration of the battery is greater than the preset temperature, the battery can stop discharging and directly charge normally. At this time, the lithium precipitation phenomenon of the battery is greatly reduced, and the total charging time is also shorter.

[0104] In some embodiments, in the step of determining the state of charge of the current battery, the charging method further comprises:

[0105] The current battery is simulated to have the first initial state of charge as the charging starting point, and is charged to the preset terminal state of charge of the battery to obtain a fourth charging time;

[0106] When the fourth charging duration is greater than the sum of the first discharging duration and the first charging duration, the current battery does not perform a discharging temperature recovery action and directly performs a charging power compensation.

[0107] It can be understood that the fourth charging duration is the total charging duration of the current battery directly charging. This scenario is applicable to the case where the first initial state of charge is high, and at this time, the total charging duration of the current battery directly charging is shorter.

[0108] Now the charging method of the battery in a low temperature state is described in the corresponding embodiment to prove the above conclusion.

[0109] The specifications of the battery are selected as follows: the battery capacity is 133 Ah, the specific heat capacity of the square shell battery is 1400 J / (Kg·℃), the battery weight is 2 kg, and the average direct current impedance of the battery at-10℃ to 10℃ is 0.003 Ohm.

[0110] For example, the initial temperature of the battery is-10℃, the first initial state of charge is 20%, the discharging temperature recovery is performed to the first intermediate state of charge 5%, which takes 270s, and the process heat Q is: Q=I 2 Rt=(266A) 2 ×0.003Ω×270s=57312.4J

[0111] Battery temperature rise ΔT:

[0112] The battery discharge end temperature is: T=T0+ΔT=-10℃+20.5℃=10.5℃

[0113] The preset termination state of charge of the battery is 97%, so according to the simulation results, the first initial state of charge is 20% directly for low temperature charging, and the charging time is 58.7min, and the charging time is 51.8min by using the charging mode of discharging temperature recovery and then charging, and the total charging time is reduced by 11.8%.

[0114] The following embodiments and comparative examples are described according to the above implementation process, and the simulation conditions of each scheme are indicated, and the simulation conditions not indicated are the same.

[0115] The other simulation conditions of each embodiment and each comparative example are the same, and each embodiment is discharged to the same first intermediate state of charge and charged to different preset termination states of charge, and each comparative example is also charged to the corresponding preset termination state of charge. It can be found that the charging mode of discharging and then charging shortens the total charging time at different preset termination states of charge, and the improvement is more than 10%.

[0116] The simulation conditions of the above-mentioned embodiments and comparative examples are the same, the first initial state of charge of the embodiments is different, and the first intermediate state of charge is also different, and the initial state of charge corresponding to the comparative examples also corresponds accordingly. It can be found by comprehensively analyzing embodiments 6 to 12 that the lower the first initial state of charge of the current battery and the lower the first intermediate state of charge, the more obvious the battery discharge temperature recovery temperature, which indicates that the battery heats up at a relatively low state of charge, and the impedance of the battery is large, so the heating effect is better. At the same time, for the battery with a higher first initial state of charge, for example, embodiments 10 to 12, the charging mode of direct charging is selected, which saves the charging time.

[0117] As can be understood from the figure, as the first intermediate state of charge gradually decreases, the battery recovery temperature increases, and when the working temperature reaches the critical value, i.e., the rated temperature, the total charging time of the current battery is the longest compared to the total charging time of the comparative example 1. The working temperature of the battery is continuously increased, and the total charging time is continuously reduced. Therefore, when the first initial state of charge is within a certain range, the rated temperature can reflect the timing selection of the battery recharging, which is beneficial to shorten the total charging time.

[0118] Referring to FIG. 2, the application provides a battery, comprising a plurality of battery monomers and a battery management device for controlling each battery monomer, and the battery management device is used to execute the above-mentioned charging method of the battery in a low temperature state.

[0119] The battery provided by the application is used to execute the above-mentioned charging method of the battery in a low temperature state during the charging process, so that each battery monomer can be charged in a low temperature state, and the probability of lithium precipitation of the battery can be reduced on the basis of shortening the charging time.

[0120] Referring to FIG. 3, the application provides a power consumption device, comprising a battery and a control module electrically connected with the battery, and the control module is used to execute the above-mentioned charging method of the battery in a low temperature state.

[0121] The power consumption device provided by the application is used to execute the above-mentioned charging method of the battery in a low temperature state during the charging process, so that the battery in the power consumption device can be charged in a low temperature state, and the probability of lithium precipitation of the battery can be reduced on the basis of shortening the charging time.

[0122] Referring to FIG. 4, the application provides a charging device, comprising a charging end and a control end electrically connected with the charging end, and the control end is used to execute the above-mentioned charging method of the battery in a low temperature state.

[0123] The charging device provided by the application is used for performing the charging method of the battery in a low-temperature state, and is used for charging the battery and the electric device in a low-temperature condition when the battery and the electric device are electrically connected with the charging end, so that the charging time is shortened, and the probability of lithium precipitation of the battery is reduced.

[0124] The above is only a preferred embodiment of the application, and is not used to limit the application. Any modification, equivalent replacement and improvement made within the spirit and principle of the application should be included in the protection scope of the application.

Claims

1. A method of charging a battery in a low temperature state, characterized by, The charging method comprises: determining the current state of charge of the battery, obtaining a first initial state of charge of the current battery, discharging the current battery to restore temperature, and obtaining a first intermediate state of charge and a first discharging duration of the current battery after discharging; charging the current battery, taking the first intermediate state of charge as the charging starting point, charging the current battery to a preset terminal state of charge under certain charging conditions, and the required charging duration is the first charging duration; the charging duration of the current battery is the sum of the first discharging duration and the first charging duration.

2. The charging method of a battery in a low temperature state according to claim 1, characterized by: In the step of determining the state of charge of the current battery, the current battery is discharged to restore temperature at a preset discharging rate.

3. The charging method of a battery in a low temperature state according to claim 2, characterized by: The preset discharging rate comprises a constant discharging rate, a linear discharging rate and a nonlinear discharging rate.

4. The charging method for a battery in a low temperature state according to claim 1, wherein: In the step of determining the state of charge of the current battery, the current battery is discharged to restore temperature to a rated temperature, and a second intermediate state of charge and a second discharging duration of the current battery at the rated temperature are obtained; charging the current battery, taking the second intermediate state of charge as the charging starting point, charging the current battery to a preset terminal state of charge under the same charging conditions, and the required charging duration is the second charging duration; the charging duration of the current battery is the sum of the second discharging duration and the second charging duration.

5. The method of claim 1, wherein, After the step of determining the state of charge of the current battery, the charging method further comprises: charging the current battery, and obtaining a second initial state of charge and a third charging duration of the current battery, taking the second initial state of charge as the discharging starting point of the current battery, and again obtaining a third intermediate state of charge and a third discharging duration of the current battery after re-discharging; taking the third intermediate state of charge as the charging starting point, charging the current battery to a preset terminal state of charge under the same charging conditions, and the required charging duration is the fourth charging duration; the charging duration of the current battery is the sum of the third charging duration, the first discharging duration, the third discharging duration and the fourth discharging duration.

6. The method of claim 1, wherein: Before the step of charging the current battery, the charging method further comprises: determining whether the current battery is involved in a direct charging mode, obtaining an initial temperature of the current battery, comparing with a preset temperature, and when the initial temperature of the current battery is higher than the preset temperature, the current battery is switched to the direct charging mode.

7. The method of claim 6, wherein: In the step of determining the state of charge of the current battery, the battery is discharged to restore temperature, and when the temperature after restoring temperature is higher than the preset temperature, the current battery is switched to the direct charging mode.

8. The method of claim 1, wherein, In the step of determining the state of charge of the current battery, the charging method further comprises: simulating the current battery to take the first initial state of charge as the charging starting point, and charging the battery to a preset terminal state of charge to obtain a fourth charging duration; When the fourth charging duration is greater than the sum of the first discharging duration and the first charging duration, the battery does not perform a discharging warm-up action and directly performs a charging power compensation.

9. A battery, characterized by: The battery management device is used for executing the charging method in the low-temperature state of the battery as claimed in any one of claims 1 to 8.

10. An electrical device, characterized by: The control module is used for executing the charging method in the low-temperature state of the battery as claimed in any one of claims 1 to 8.

11. A charging device, characterized by: The control terminal is used for executing the charging method in the low-temperature state of the battery as claimed in any one of claims 1 to 8.

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