CN113316878A

CN113316878A - Charging method, electronic device, and storage medium

Info

Publication number: CN113316878A
Application number: CN202080008490.3A
Authority: CN
Inventors: 张涵翔
Original assignee: Ningde Amperex Technology Ltd
Current assignee: Ningde Amperex Technology Ltd
Priority date: 2020-03-25
Filing date: 2020-03-25
Publication date: 2021-08-27
Also published as: WO2021189319A1

Abstract

The present application provides a method for charging a battery, the method comprising: in a first stage, charging the battery to a voltage of a first stage by a first charging method or a second charging method; in a second stage, charging the battery with a third charging method The battery is charged to a second-stage voltage, and the second-stage voltage is greater than the first-stage voltage, wherein the third charging mode adopts the first charging mode or the second charging mode. The present application also provides an electronic device and a storage medium. According to the charging method provided by the present application, the charging speed of the battery during the charging process can be improved, and the total charging time can be shortened.

Description

Charging method, electronic device, and storage medium

Technical Field

The present disclosure relates to the field of battery technologies, and in particular, to a battery charging method, an electronic device, and a storage medium.

Background

The charging method generally adopted at present is a constant current and constant voltage charging method, that is, constant current charging is carried out to a charging limit voltage, and then constant voltage charging is carried out at the charging limit voltage, wherein the charging limit voltage refers to a maximum voltage value when the battery is changed from constant current charging to constant voltage charging, or a limit voltage written on a package of a battery product. The constant-current constant-voltage charging method is adopted because the polarization phenomenon exists in the battery in the charging process, and the polarization is more obvious when the current is larger. When the constant current is charged to the charging limit voltage, the battery cell is not fully charged due to polarization, and therefore constant voltage charging needs to be continued. In the constant current stage, the charging current windows are different because the batteries are in different charge states. In the existing charging method, basically, constant-current charging is carried out to cut-off voltage in one step, and then constant-voltage charging is carried out, so that current windows of different charge states in a constant-current stage cannot be effectively utilized. And when the charging current is too large in the constant current charging process, the risk of lithium precipitation exists, and when the charging current is too small, the charging speed is too slow.

Disclosure of Invention

In view of the above, it is desirable to provide a charging method, an electronic device and a storage medium, which can ensure the cycle life of a battery and shorten the total charging time of the battery.

An embodiment of the present application provides a method of charging a battery, the method including a first stage and a second stage. In the first stage, the battery is charged to the first stage voltage in the first charging mode or the second charging mode. The first charging mode comprises N charging sub-stages in sequence, wherein N is an integer greater than or equal to 2, the N charging sub-stages are respectively defined as the ith charging sub-stage, and i is 2, 3, … and N; charging the battery with one of an ith current, an ith voltage and an ith power at the ith charging sub-stage; in the (i +1) th charging sub-stage, charging the battery by using one of the (i +1) th current, the (i +1) th voltage and the (i +1) th power; wherein the charging current of the battery in the (i +1) th charging sub-phase is less than or equal to the charging current in the (i) th charging sub-phase. The second charging mode comprises M charging sub-stages in sequence, wherein M is an integer greater than or equal to 2, the M charging sub-stages are respectively defined as a jth charging sub-stage, j is 1, 2, … and M, and each jth charging sub-stage comprises a jth front charging sub-stage and a jth rear charging sub-stage; during one of the jth pre-charge sub-phase and the jth post-charge sub-phase, charging or discharging the battery without charging or with a jth pre-charge sub-current for a time period of Tj 1; charging the battery at a jth post-charge sub-current for a duration of Tj2 in the other of the jth pre-charge sub-phase and the jth post-charge sub-phase; wherein the absolute value of the jth pre-charge sub-current is smaller than the absolute value of the jth post-charge sub-current. In the second stage, the battery is charged to a second stage voltage by a third charging mode, wherein the second stage voltage is greater than the first stage voltage, and the third charging mode adopts the first charging mode or the second charging mode.

According to some embodiments of the present application, when the third charging mode adopts the first charging mode, the number N of the charging sub-stages between the first charging mode and the second charging mode is the same.

According to some embodiments of the present application, when the second charging method is adopted in the third charging method, the number M of the charging sub-stages between the first charging method and the second charging method is the same.

According to some embodiments of the present application, the i +1 th voltage is greater than or equal to the i-th voltage.

According to some embodiments of the present application, the i +1 th power is less than or equal to the i-th power.

According to some embodiments of the present application, an average value of the charging current of the j +1 th charging sub-stage is less than or equal to the charging current of the j sub-stage, and when the third charging mode adopts the second charging mode, the average value of the charging current of the j charging sub-stage is less than the charging current of the first charging mode or the second charging mode.

According to some embodiments of the present application, the first-stage voltage is equal to a charge-limiting voltage of the battery, and the second-stage voltage is less than an oxidative decomposition voltage of an electrolyte in the battery.

According to some embodiments of the present application, the second-stage voltage is less than or equal to the first-stage voltage plus 500 millivolts.

According to some embodiments of the application, the method further comprises: in a third stage, the battery is charged at a constant voltage with the second-stage voltage.

According to some embodiments of the present application, the charging current in the third charging mode is less than or equal to the charging current in the first charging mode or the second charging mode.

An embodiment of the present application provides an electronic device, which includes a battery and a processor, wherein the processor is configured to execute the charging method as described above.

An embodiment of the present application provides a storage medium having at least one computer instruction stored thereon, the computer instruction being loaded by a processor and used for executing the method for charging a battery as described above.

Embodiments of the present application provide for charging to a first phase voltage by at least one of constant current, constant voltage, or constant power during the first phase; and is charged in a second stage with at least one of constant current, constant voltage, or constant power. Alternatively, the first stage and the second stage may be a pulse charging or a pulse charging/discharging charging system. The charging method can optimize the early stage (first stage) of battery charging so as to reduce the early conventional charging time, reduce the risk of lithium precipitation, shorten the high potential time of the cathode, and further improve the cycle life of the battery core and improve the charging speed. And the charging limit voltage of the battery is increased from the first-stage voltage to the second-stage voltage, so that the charging speed of the battery in the charging process can be increased, and the total charging time can be shortened.

Drawings

Fig. 1 is a schematic structural diagram of an electronic device according to an embodiment of the present application.

Fig. 2 is a flowchart of a method of charging a battery according to an embodiment of the present application.

Fig. 3 is a graph of voltage versus current during charging of a battery according to an embodiment of the present application.

Fig. 4 is a schematic diagram of the current and voltage changes with time during the charging process of the battery according to the first embodiment of the present application.

Fig. 5 is a schematic diagram showing the change of current and voltage with time during charging of a battery according to the second embodiment of the present application.

FIG. 6 is a graph of power and voltage over time during a first phase and current and voltage over time during a second phase according to an embodiment of the present application.

Fig. 7 is a schematic diagram showing the change of current and voltage with time during charging of a battery according to the third embodiment of the present application.

Fig. 8 is a schematic diagram of the current and voltage changes over time during charging of a battery according to the fourth embodiment of the present application.

Fig. 9 is a block diagram of a charging system according to an embodiment of the present application.

Description of the main elements

Electronic device 1

Charging system 10

Processor 11

Battery 12

First charging module 101

Second charging module 102

Third charging module 103

The following detailed description will further illustrate the invention in conjunction with the above-described figures.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments of the present application.

All other embodiments that can be obtained by a person skilled in the art without inventive step based on the embodiments in this application are within the scope of protection of this application.

Referring to fig. 1, a charging system 10 operates in an electronic device 1. The electronic device 1 includes, but is not limited to, at least one processor 11 and a battery 12, and the above elements may be connected via a bus or directly.

Fig. 1 is only an example of the electronic apparatus 1. In other embodiments, the electronic device 1 may also include more or fewer elements, or have a different arrangement of elements. The electronic device 1 may be an electric motorcycle, an electric bicycle, an electric automobile, a mobile phone, a tablet computer, a digital assistant, a personal computer, or any other suitable rechargeable device.

In one embodiment, the battery 12 is a rechargeable battery for providing power to the electronic device 1. For example, the battery 12 may be a lithium ion battery, a lithium polymer battery, a lithium iron phosphate battery, or the like. The battery 12 includes at least one cell, and the battery 12 can be repeatedly charged in a rechargeable manner.

Although not shown, the electronic device 1 may further include a Wireless Fidelity (WiFi) unit, a bluetooth unit, a speaker, and other components, which are not described in detail herein.

Referring to fig. 2, fig. 2 is a flowchart illustrating a method for charging a battery according to an embodiment of the present disclosure. The method of charging the battery may include the steps of:

step S21: in the first stage, the battery is charged to the first stage voltage in the first charging mode or the second charging mode.

In this embodiment, the first charging mode includes N charging sub-stages in sequence, where N is an integer greater than or equal to 2, and the N charging sub-stages are respectively defined as the ith charging sub-stage, where i is 2, 3, …, and N. And charging the battery by one of the ith current, the ith voltage and the ith power in the ith charging sub-phase. And in the (i +1) th charging sub-phase, charging the battery by using one of the (i +1) th current, the (i +1) th voltage and the (i +1) th power. The charging current of the battery in the (i +1) th charging sub-phase is less than or equal to the charging current in the (i) th charging sub-phase.

In this embodiment, the i +1 th voltage is greater than or equal to the i-th voltage, and the i +1 th power is less than or equal to the i-th power.

The second charging mode comprises M charging sub-stages in sequence, wherein M is an integer greater than or equal to 2, the M charging sub-stages are respectively defined as a jth charging sub-stage, j is 1, 2, … and M, and each jth charging sub-stage comprises a jth front charging sub-stage and a jth rear charging sub-stage; during one of the jth pre-charge sub-phase and the jth post-charge sub-phase, charging or discharging the battery without charging or with a jth pre-charge sub-current for a time period of Tj 1; charging the battery with a jth post-charge sub-current for a duration of Tj2 in the other of the jth pre-charge sub-phase and the jth post-charge sub-phase. Wherein the absolute value of the jth pre-charge sub-current is smaller than the absolute value of the jth post-charge sub-current.

In this embodiment, the average value of the charging current in the j +1 th charging sub-stage is less than or equal to the charging current in the j sub-stage, and when the third charging mode adopts the second charging mode, the average value of the charging current in the j charging sub-stage is less than the charging current in the first charging mode or the second charging mode.

It should be noted that the first-stage voltage is equal to the charge limit voltage of the battery 12 (which can be understood as the charge limit voltage described in the background).

Step S22: in the second stage, the battery is charged to a second stage voltage by a third charging mode, wherein the second stage voltage is greater than the first stage voltage, and the third charging mode adopts the first charging mode or the second charging mode.

It should be noted that, when the third charging manner adopts the first charging manner, the number N of the charging sub-stages in the third charging manner may be the same as or different from the number N of the charging sub-stages in the first charging manner. That is, when the third charging manner adopts the first charging manner, the number N of the charging sub-stages in the second stage may be the same as or different from the number N of the charging sub-stages in the first stage.

When the third charging mode adopts the second charging mode, the number M of the charging sub-stages in the third charging mode may be the same as or different from the number M of the charging sub-stages in the second charging mode. That is, when the third charging manner adopts the second charging manner, the number M of the charging sub-stages in the second stage may be the same as or different from the number M of the charging sub-stages in the first stage.

In this embodiment, the charging current in the third charging mode is less than or equal to the charging current in the first charging mode or the second charging mode.

In one embodiment, when the battery 12 is charged in the first charging manner in the first stage, the first stage includes N charging sub-stages in sequence, where N is a positive integer, and the N charging sub-stages are respectively defined as the ith charging sub-stage, i is 2, …, and N. During the ith charging sub-phase, the battery 12 is charged with one of a constant ith current, a constant ith voltage, and a constant ith power. When the battery 12 is charged in the first charging manner in the second stage, the second stage includes N charging sub-stages in sequence, where N is a positive integer, and the N charging sub-stages are respectively defined as the ith charging sub-stage, i is 2, …, and N. During the ith charging sub-phase, the battery 12 is charged with one of a constant ith current, a constant ith voltage, and a constant ith power. It can be understood that the number N of the charging sub-stages in the first stage and the number N of the charging sub-stages in the second stage may be the same or different.

In one embodiment, when the battery 12 is charged in the second charging manner in the first stage, the first stage includes M charging sub-stages in sequence, M is an integer greater than or equal to 2, the M charging sub-stages are respectively defined as jth charging sub-stage, j is 1, 2, …, and M, and each jth charging sub-stage includes a jth pre-charging sub-stage and a jth post-charging sub-stage; during one of the jth pre-charge sub-phase and the jth post-charge sub-phase, charging or discharging the battery without charging or with a jth pre-charge sub-current for a time period of Tj 1; charging the battery with a jth post-charge sub-current for a duration of Tj2 in the other of the jth pre-charge sub-phase and the jth post-charge sub-phase. When the battery 12 is charged in the second stage by the second charging manner, the second stage includes M charging sub-stages in sequence, M is an integer greater than or equal to 2, the M charging sub-stages are respectively defined as a jth charging sub-stage, j is 1, 2, …, and M, and each jth charging sub-stage includes a jth pre-charging sub-stage and a jth post-charging sub-stage; during one of the jth pre-charge sub-phase and the jth post-charge sub-phase, charging or discharging the battery without charging or with a jth pre-charge sub-current for a time period of Tj 1; charging the battery with a jth post-charge sub-current for a duration of Tj2 in the other of the jth pre-charge sub-phase and the jth post-charge sub-phase. It is understood that the number M of the charging sub-stages in the first stage and the number M of the charging sub-stages in the second stage may be the same or different.

In one embodiment, when the battery 12 is charged in the first charging manner in the first stage, the first stage includes N charging sub-stages in sequence, where N is a positive integer, and the N charging sub-stages are respectively defined as the ith charging sub-stage, i is 2, …, and N. During the ith charging sub-phase, the battery 12 is charged with one of a constant ith current, a constant ith voltage, and a constant ith power. When the battery 12 is charged in the second stage by the second charging manner, the second stage includes M charging sub-stages in sequence, M is an integer greater than or equal to 2, the M charging sub-stages are respectively defined as a jth charging sub-stage, j is 1, 2, …, and M, and each jth charging sub-stage includes a jth pre-charging sub-stage and a jth post-charging sub-stage; during one of the jth pre-charge sub-phase and the jth post-charge sub-phase, charging or discharging the battery without charging or with a jth pre-charge sub-current for a time period of Tj 1; charging the battery with a jth post-charge sub-current for a duration of Tj2 in the other of the jth pre-charge sub-phase and the jth post-charge sub-phase.

In one embodiment, when the battery 12 is charged in the second charging manner in the first stage, the first stage includes M charging sub-stages in sequence, M is an integer greater than or equal to 2, the M charging sub-stages are respectively defined as jth charging sub-stage, j is 1, 2, …, and M, and each jth charging sub-stage includes a jth pre-charging sub-stage and a jth post-charging sub-stage; during one of the jth pre-charge sub-phase and the jth post-charge sub-phase, charging or discharging the battery without charging or with a jth pre-charge sub-current for a time period of Tj 1; charging the battery with a jth post-charge sub-current for a duration of Tj2 in the other of the jth pre-charge sub-phase and the jth post-charge sub-phase. When the battery 12 is charged in the first charging manner in the second stage, the second stage includes N charging sub-stages in sequence, where N is a positive integer, and the N charging sub-stages are respectively defined as the ith charging sub-stage, i is 2, …, and N. During the ith charging sub-phase, the battery 12 is charged with one of a constant ith current, a constant ith voltage, and a constant ith power.

Since the charging current in the 1 st charging sub-phase of the second phase is smaller than the first phase current and the charging current in the i +1 st charging sub-phase is smaller than or equal to the charging current in the i-th charging sub-phase, the anode potential of the battery 12 is not lower than a lithium-evolving potential. The lithium-evolving potential can be obtained by the following approach test. For the battery 12 in this embodiment, another three-electrode battery with the same specification is manufactured, and the three-electrode battery includes one more electrode than the battery 12 in this embodiment, that is, three electrodes, namely an anode, a cathode and a reference electrode. The reference electrode material was lithium and the three-electrode cell was tested to obtain the lithium-evolving potential of the anode of the cell 12 of this example.

The specific test method of the lithium-separating potential of the anode comprises the following steps: and manufacturing a plurality of three-electrode batteries, respectively adopting charging currents with different multiplying powers (such as 1C, 2C and 3C) to charge and discharge the three-electrode batteries, circulating for a plurality of times (such as 10 times), and detecting the potential difference between the anode and the reference electrode in the charging and discharging process. And then, fully charging and disassembling the three-electrode battery, and respectively observing whether the lithium precipitation phenomenon occurs on the anode of the three-electrode battery charged by different multiplying powers (namely observing whether metal lithium is precipitated on the surface of the anode). And determining the maximum multiplying power corresponding to the three-electrode battery without the lithium separation phenomenon, and taking the minimum value of the potential difference between the anode and the reference electrode in the charging and discharging process under the multiplying power as the lithium separation potential of the anode. It should be additionally noted that: the charging current of a lithium battery is generally referred to as C, which is a numerical value corresponding to the capacity of the lithium battery. The capacity of the lithium battery is generally expressed by Ah and mAh, for example, when the battery capacity is 1200mAh, the corresponding 1C is 1200mA, and 0.2C is 240 mA.

As another example, a plurality of three-electrode batteries were charged and discharged with charging currents of 1C, 2C, and 3C, respectively, and cycled 10 times. The disassembly of the three-electrode battery shows that the lithium precipitation phenomenon does not occur in the anode when 1C and 2C are adopted for charging and discharging, and the lithium precipitation phenomenon occurs in the anode when 3C is adopted for charging and discharging. Then, the minimum value of the potential difference between the anode and the reference electrode at the 2C magnification is the lithium-precipitation potential of the anode. In addition, the lithium-analyzing potential of the cathode can also be tested in a similar manner, and will not be described herein again. The anode potential and cathode potential of the cell 12 can be further understood through the above-described testing procedure for the lithium evolution potential of the anode as follows: the anode potential is the potential difference between the anode and the reference electrode, namely the anode-to-lithium potential, and the cathode potential is the potential difference between the cathode and the reference electrode, namely the cathode-to-lithium potential.

The second stage voltage is less than the oxidative decomposition voltage of the electrolyte in the cell 12. The oxidative decomposition voltage of the electrolyte in the battery can be understood as follows: when the potential of the battery exceeds a certain potential threshold, solvent molecules, additive molecules and even impurity molecules in the electrolyte undergo irreversible reduction or oxidative decomposition at the interface between the electrode and the electrolyte, and the phenomenon is called electrolyte decomposition. The potential threshold is the reductive decomposition voltage and the oxidative decomposition voltage of the electrolyte in the battery.

The oxidative decomposition voltage of the electrolyte can be obtained by the following means test. For example, a symmetrical battery (e.g., a button cell using Pt electrodes) is fabricated, and the corresponding electrolyte, i.e., the same electrolyte as the battery 12 described in this embodiment, is injected into the symmetrical battery. Referring to fig. 3, fig. 3 illustrates that a gradually increasing voltage is applied to the symmetrical battery, and the instrument scans the voltage versus the current to obtain the corresponding relationship between the voltage and the current, wherein the horizontal axis represents the voltage and the vertical axis represents the current. More specifically, after the voltage is applied, the current value sampled by the instrument at the second voltage point is taken as an initial current value (corresponding to the position P1 in fig. 3), and then, as the voltage gradually increases, when the current value sampled by the instrument is equal to 100 times of the initial current value, the voltage corresponding to this time is taken as the oxidative decomposition voltage of the electrolyte, which is, in the example of fig. 3, 6.2 volts corresponding to the position P2. In this embodiment, the second-stage voltage is also less than or equal to the first-stage voltage plus 500 millivolts.

In the nth charging sub-phase or the mth charging sub-phase of the second phase, the battery 12 is charged to the second-phase voltage, and at this time, the cut-off condition for charging the battery 12 is a cut-off voltage, a cut-off current, or a cut-off capacity. More specifically, at the nth charging sub-stage or the mth charging sub-stage, when the charging current of the battery 12 is equal to the cutoff current, the generated charging voltage is equal to the cutoff voltage, or it is detected that the capacity (SOC) of the battery 12 is equal to the cutoff capacity, the charging of the battery 12 is stopped, i.e., the charging is cut off. For the batteries 12 with different specifications, the cut-off current, the cut-off voltage and the cut-off capacity can be obtained by observing that the cathode of the three-electrode battery does not generate over-lithium removal in the test mode of the three-electrode battery, so as to ensure that the electric capacity of the battery 12 is equivalent to that of the conventional charging mode in the prior art and ensure that the cathode of the battery 12 does not generate over-lithium removal.

In addition, it is to be additionally explained that: in this embodiment, the values of the first-stage current, the first-stage voltage, one of the ith current, the ith voltage, and the ith power of the ith sub-stage of the second stage, the second-stage voltage, and the cutoff condition may be pre-stored in the battery 12 or the processor 11, and the processor 11 reads the pre-stored values to correctly control the charging system 10 to perform charging.

Referring to fig. 4, the horizontal axis represents time, and the vertical axis represents current level. In the first phase, at times t1, t2, …, t (i-2), t (i-1), ti, … tN, the voltage of the battery 12 is U1, U2, …, U (i-1), Ui, …, Ucl, respectively. In the second stage, at times t1', t2', t3', t4', t5', …, t (i-1) ', ti ', t (i +1) ', … tN ', the voltages of the battery 12 are Ucl, U1', U2', …, Ui ', U (i +1) ', …, Um, respectively. Note that tN and t1' are the same time.

In a first phase, charging the battery 12 to a voltage U1 at a constant current I1 for a time period of 0 to t 1; charging to a voltage U2 at a constant current I2 during a time t 1-t 2; charging to a voltage U (I-1) with a constant current I (I-1) during a time t (I-2) to t (I-1); charging to a voltage Ui with a constant current Ii between time ti-1 and ti; during time t (N-1) to tN, voltage Ucl is charged at constant current Icl. During time t2 to t (i-2), and during time ti to t (N-1), similar charging is performed, but omitted from the figure and not shown.

In the second stage, charging to the voltage U1 'with the constant current I1' from time t1 'to t 2'; charging the battery with a constant voltage U1' from time t2' to time t3', wherein the charging current decreases from I1' to I2 '; charging the battery to a voltage U2 'with a constant current I2' during a time t3 'to t 4'; charging the battery with a constant voltage U2' between time t4' and t5 '; charging to a voltage Ui 'with a constant current Ii' during a time t (i-1) 'to ti'; charging the battery with a constant voltage Ui ' from time ti ' to t (I +1) ', wherein the charging current decreases from I1' to I (I +1) '; charging to a voltage Um with a constant current Im during a time t (N-2) 'to t (N-1)'; during the time period t (N-1) ' to tN ', the battery is charged with a constant voltage Um, and the charging current decreases from Im to Im ' during the time period. During time t5 'to t (i-1)' and during time t (i +1) 'to t (N-1)', similar charging is performed, but omitted from the drawing.

In each of the N charging sub-stages of the first stage, the battery 12 is charged with a constant charging current, I1 ≧ I2 ≧ Icl … ≧ Icl, U1 ≦ U2 ≦ … ≦ Ucl; in each of the N charging sub-stages of the second stage, the battery 12 is charged alternately with a constant charging current and a constant voltage, Icl ≧ I1' ≧ I2' ≧ Im ' … ≧ Im ', Ucl ≦ U1' ≦ U2 ≦ … ≦ Um.

Referring to fig. 5, the horizontal axis represents time, and the vertical axis represents current magnitude. In the first phase, at times t1, t2, …, ti, … tN, the voltage of the battery 12 is U1, U2, …, Ui, …, Ucl, respectively. In the second stage, at times t1', t2', …, ti ', t (i +1) ', … tN ', the voltage of the battery 12 is U1', U2', …, Ui ', U (i +1) ', …, Um, respectively. Note that tN and t1' are the same time.

In a first phase, charging the battery 12 at a constant voltage U1 to a current of I1 between time 0 and t 1; charging to a current of I2 at a constant voltage U2 during a time t 1-t 2; charging to a current Ii at a constant voltage Ui between time t (i-1) and time ti; during time t (N-1) to tN, constant voltage Ucl is charged to current Icl. Similar charging is performed between time t2 and t (i-1), and between time ti and t (N-1), but is omitted from the figure and not shown.

In the second stage, charging to the voltage U1 'with the constant current I1' from time t1 'to t 2'; charging the battery with a constant voltage U1' from time t2' to time t3', wherein the charging current decreases from I1' to I2 '; charging the battery to a voltage U2 'with a constant current I2' during a time t3 'to t 4'; charging the battery with a constant voltage U2' between time t4' and t5 '; charging to a voltage Ui 'with a constant current Ii' during a time t (i-1) 'to ti'; charging the battery with a constant voltage Ui ' from time ti ' to t (I +1) ', wherein the charging current decreases from Ii ' to I (I +1) '; charging to a voltage Um with a constant current Im during a time t (N-2) 'to t (N-1)'; during the time period t (N-1) ' to tN ', the battery is charged with a constant voltage Um, and the charging current decreases from Im to Im ' during the time period. During time t5 'to t (i-1)' and during time t (i +1) 'to t (N-2)', similar charging is performed, but omitted from the drawing.

In each of the N charging sub-stages of the first stage, the battery 12 is charged at a constant charging voltage, U1 ≦ U2 ≦ … ≦ Ucl, and I1 ≧ I2 ≧ … ≧ Icl. In each of the N charging sub-stages of the second stage, the battery 12 is charged alternately with a constant charging current and a constant charging voltage, and Ucl ≦ U1' ≦ U2' ≦ … ≦ Um, Icl ≧ I1' ≧ I2' ≧ … ≧ Im '.

Referring to fig. 6, the horizontal axis represents time, the left vertical axis represents power level, and the right vertical axis represents current level. In the first phase, at times t1, t2, …, t (i-1), ti, … tN, the voltage of the battery 12 is U1, U2, …, U (i-1), Ui, …, Ucl, respectively. In the second phase, at times t2', t4', …, ti ', …, t (N-1) ' the voltage of the battery 12 is U1', U2', …, Ui ', …, Um, respectively. Note that tN and t1' are the same time.

In a first phase, charging the battery 12 to a voltage of U1 at a constant power P1 for a time period of 0 to t 1; charging to a voltage U2 at a constant power P2 during a time t 1-t 2; charging to a voltage U (i-1) with a constant power P (i-1) between time t (i-2) and time t (i-1); charging to a voltage Ui with a constant power Pi for a time t (i-1) to ti; during time t (N-1) to tN, voltage Ucl is charged at constant power Pcl. During time t2 to t (i-2), and during time ti to t (N-1), similar charging is performed, but omitted from the figure and not shown.

In the second stage, charging to the voltage U1 'with the constant current I1' from time t1 'to t 2'; charging the battery with a constant voltage U1' from time t2' to time t3', wherein the charging current decreases from I1' to I2 '; charging the battery to a voltage U2 'with a constant current I2' during a time t3 'to t 4'; charging the battery with a constant voltage U2' between time t4' and t5 '; charging to a voltage Ui 'with a constant current Ii' during a time t (i-1) 'to ti'; charging the battery with a constant voltage Ui ' from time ti ' to t (I +1) ', wherein the charging current decreases from I1' to I (I +1) '; charging to a voltage Um with a constant current Im during a time t (N-2) 'to t (N-1)'; during the time period t (N-1) ' to tN ', the battery is charged with a constant voltage Um, and the charging current decreases from Im to Im ' during the time period. During time t5 'to t (i-1)' and during time t (i +1) 'to t (N-2)', similar charging is performed, but omitted from the drawing.

In each of the N charging sub-stages of the first stage, the battery 12 is charged at a constant power, and P1 ≧ P2 ≧ … ≧ Pcl, U1 ≦ U2 ≦ … ≦ Ucl. In each of the N charging sub-stages of the second stage, the battery 12 is charged alternately with a constant charging current and a constant charging voltage, and Ucl ≦ U1' ≦ U2' ≦ … ≦ Um, Icl ≧ I1' ≧ I2' ≧ … ≧ Im '.

Referring to fig. 7, the horizontal axis represents time, and the vertical axis represents current level. In the first phase, at times t1, t2, …, t (i-2), t (i-1), ti, … tN, the voltage of the battery 12 is U1, U2, …, U (i-1), Ui, …, Ucl, respectively. In the second phase, at times t2', t4', …, t (i-1) ', ti', …, t (N-1) ', the voltage of the battery 12 is U1', U2', …, Ui', …, Um, respectively. Note that tN and t1' are the same time.

In a first phase, charging the battery 12 to a voltage U1 at a constant current I1 for a time period of 0 to t 1; charging the battery with a constant voltage U1 during a time period from t1 to t2, wherein the charging current decreases from I1 to I2; charging to a voltage U2 at a constant current I2 during a time t 2-t 3; charging the battery with a constant voltage U2 during a time period from t3 to t4, wherein the charging current decreases from I2 to I3; charging to a voltage Ui with a constant current Ii between time t (i-2) and time t (i-1); charging the battery with a constant voltage Ui between time t (i-1) and time ti; charging to voltage Ucl at constant current Icl between time t (N-2) and time t (N-1); during time t (N-1) to tN, the battery is charged at a constant voltage Ucl, and the charging current decreases from Icl to I1'. During time t4 to t (i-2), and during time ti to t (N-2), similar charging is performed, but omitted from the figure and not shown.

In each of the N charging sub-stages of the first stage, the battery 12 is charged alternately with a constant charging current and a constant charging voltage, I1 ≧ I2 ≧ … ≧ Icl, U1 ≦ U2 ≦ … ≦ Ucl. In each of the N charging sub-stages of the second stage, the battery 12 is also charged alternately with a constant charging current and a constant charging voltage, and I1' ≧ I2' ≧ … ≧ Im ', U1' ≦ U2' ≦ … ≦ Um, and Icl ≧ I1', Ucl ≦ U1 '.

When the battery 12 is charged by the second charging method, the first stage includes M charging sub-stages in sequence, M is an integer greater than or equal to 2, the M charging sub-stages are respectively defined as a jth charging sub-stage, j is 1, 2, …, and M, and each jth charging sub-stage includes a jth pre-charging sub-stage and a jth post-charging sub-stage. The second stage also includes M charging sub-stages in sequence, M is an integer greater than or equal to 2, the M charging sub-stages are respectively defined as jth charging sub-stage, j is 1, 2, …, and M, and each of the jth charging sub-stages includes a jth pre-charging sub-stage and a jth post-charging sub-stage. The number M of the charge sub-stages in the first stage may be the same as or different from that in the second stage.

In one of the jth pre-charge sub-phase and the jth post-charge sub-phase, the processor 11 controls the charging system 10 to charge or discharge the battery 12 with a jth pre-charge sub-current for a time period Tj1 without charging the battery 12. In the other of the jth pre-charge sub-phase and the jth post-charge sub-phase, the processor 11 controls the charging system 10 to charge the battery 12 at a jth post-charge sub-current for a duration of Tj 2. And the absolute value of the j-th pre-charging sub-current is smaller than that of the j-th post-charging sub-current.

That is, in each of the j-th charging sub-stages, the battery 12 is charged in a pulse charging or pulse charging and discharging manner, and the average value of the charging current of the j + 1-th charging sub-stage is less than or equal to the charging current of the j-th charging sub-stage, for example, (1 st front charging sub-current × T11+ 1 st rear charging sub-current × T12)/(T11+ T12) is greater than or equal to (2 nd front charging sub-current × T21+ 2 nd rear charging sub-current × T22)/(T21+ T22), (2 nd front charging sub-current × T21+ 2 nd rear charging sub-current × T22)/(T21+ T22) is greater than or equal to (3 rd front charging sub-current × T31+ 3 rd rear charging sub-current × T32)/(T31+ T32), and so on. The sum of the time length of each Tj1 and the time length of each Tj2 is the charging period or the charging and discharging period of the pulse charging or the pulse charging and discharging in the j charging sub-phase.

Further, it is to be noted that: in this embodiment, the jth pre-charge sub-phase is charged or discharged with the jth pre-charge sub-current for a duration of Tj1, and the jth post-charge sub-phase is charged with the jth post-charge sub-current for a duration of Tj 2. In other embodiments, the jth pre-charge sub-phase may be charged with the jth post-charge sub-current for a time period Tj2, and the jth post-charge sub-phase may be charged with the jth pre-charge sub-current or discharged for a time period Tj 1. In other embodiments, it may also be that the charging is not performed or is left (i.e. the charging current is 0) for the duration Tj1 in the jth pre-charging sub-phase, and the charging or discharging is performed with the jth post-charging sub-phase for the duration Tj2 in the jth post-charging sub-phase.

Referring to fig. 8, the horizontal axis represents time, and the vertical axis represents current level. In the first phase, during the time period from 0 to t1, the processor 11 controls the charging system 10 to charge the battery 12 to the voltage U1 at the current I1. During the time period t1 to t1000, i.e. during each charging phase from the 1 st charging sub-phase to the 1000 th charging sub-phase of the first phase, the processor 11 controls the charging system 10 to charge the battery 12 with the current I2, and then charge the battery 12 with the current I3. During the time tx to t1000, similar charging is performed, but omitted from the drawing.

During the time period t1000 to t2000, i.e. during each sub-charging period from the 1001 st charging period to the 2000 th charging period of the first period, the processor 11 controls the charging system 10 to charge the battery 12 at the current I10011, and then to stand the battery 12 (i.e. without charging or discharging). During the time ty to t2000, similar charging is performed, but omitted from the drawing and not shown. During the time period t2000 to tM, i.e. during each charging phase from the 2001 th charging sub-phase to the M th charging sub-phase of the first phase, the processor 11 controls the charging system 10 to charge the battery 12 with the current I20011 and then discharge the battery 12 with the current I20012 until the voltage of the battery 12 is equal to the voltage Ucl (i.e. the cut-off voltage). During the time t2002 to t (M-1), similar charging is performed, but omitted from the drawing and not shown.

That is, in the M charging sub-phases of the first phase, the battery 12 is charged in three different pulse charging or pulse discharging manners. It should be additionally noted that: the charging period or charging and discharging period of the pulse charging or pulse charging and discharging of each of the M charging sub-stages is the same, i.e., t1 is (t1001-t1000) is (t2001-t2000), while in other embodiments, the charging period or charging and discharging period of different pulse charging or pulse charging and discharging may be different.

In the second stage, charging to the voltage U1 'with the constant current I1' from time t1 'to t 2'; charging the battery with a constant voltage U1' from time t2' to time t3', wherein the charging current decreases from I1' to I2 '; charging the battery to a voltage U2 'with a constant current I2' during a time t3 'to t 4'; charging the battery with a constant voltage U2' between time t4' and t5 '; charging to a voltage Ui 'with a constant current Ii' during a time ti 'to t (i + 1)'; charging the battery with a constant voltage Ui ' from time t (I +1) ' to t (I +2) ' during which time the corresponding charging current decreases from I1' to current I (I +1) '; charging to a voltage Um with a constant current Im during a time t (M-2) 'to t (M-1)'; during the time period from t (M-1) ' to tM ', the battery is charged with a constant voltage Um, and the charging current decreases from Im to Im ' during the time period. During time t5 'to ti', and during time t (i +2) 'to t (M-2)', similar charging is performed, but omitted from the figure and not shown.

Step S23: in a third stage, the battery is charged at a constant voltage with the second-stage voltage.

In this embodiment, in the third stage, the battery is charged with the second-stage voltage until the battery reaches the full charge state, thereby completing the entire charging process.

In summary, the charging method charges the battery to the first-stage voltage in the first stage by at least one of a constant current, a constant voltage or a constant power, that is, in the first stage, one or more of the first stage and performs one or more times of charging; and charging the battery to a second stage voltage in the second stage by at least one of constant current, constant voltage or constant power, i.e., one or more of these and performing one or more charges in the second stage. Alternatively, the first stage and the second stage may be a pulse charging or a pulse charging/discharging charging system. The charging method can optimize the early stage (first stage) of battery charging, so that the early-stage conventional charging time is greatly reduced, the risk of lithium precipitation is reduced, the high potential time of the cathode is shortened, the cycle life of the battery cell is prolonged, and the charging speed is increased. And the charging voltage of the battery is increased from the first-stage voltage (i.e. the charging limiting voltage in the background art) to the second-stage voltage, so that the charging speed of the battery in the charging process can be increased, and the total charging time can be shortened.

In order to make the object, technical solution and technical effect of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. Comparative examples and battery systems used in the examples and comparative examples of the present application were LiCoO₂The cathode is graphite, the anode is graphite, the diaphragm, electrolyte and the packaging shell are added, and the cathode is prepared by the processes of mixing, coating, assembling, forming, aging and the like. And adding a reference electrode between the cathode and anode plates of part of the battery cell in the winding process to manufacture a three-electrode battery for testing and comparing the difference between the cathode potential and the anode potential of the battery in the charging process.

The charging limit voltage Ucl of the batteries of the comparative examples and the examples is 4.4V, and the charging method of the application is applicable to batteries of various voltage systems and is not limited to the 4.4V system. The charging speed and the capacity retention rate after 500 cycles were compared by comparing the charging method in the prior art (constant current and constant voltage charging) adopted in the comparative example with the charging method in the present application adopted in the examples.

Comparative example 1 set forth below charges the battery using a charging method of the prior art, and comparative example 2 charges the battery using a charging method of the prior art that boosts the voltage of a constant voltage charging process.

Comparative example 1

Ambient temperature: at 45 ℃.

And (3) charging and discharging processes:

the method comprises the following steps: charging the battery with a constant current of 0.7C until the voltage of the battery reaches a cut-off voltage of 4.4V (which can be understood as a charge limiting voltage);

step two: continuously charging the battery by using the constant voltage of 4.4V until the current of the battery reaches the cutoff current of 0.05C;

step three: standing the battery for 5 minutes;

step four: discharging the battery by using a constant current of 0.5C until the voltage of the battery is 3.0V;

step five: standing the battery for 5 minutes;

step six: repeating the steps from the first step to the fifth step for 500 cycles.

Comparative example 2

The ambient temperature was 45 ℃.

And (3) charging and discharging processes:

the method comprises the following steps: charging the battery with a constant current of 0.7C until the voltage of the battery reaches 4.4V;

step two: the battery was continuously charged with a constant current of 0.5C until the voltage of the battery reached a cut-off voltage of 4.45V (which can be understood as a charge limiting voltage);

step three: charging the battery with a constant voltage of 4.45V until the current of the battery reaches a cutoff current of 0.13C;

step four: standing the battery for 5 minutes;

step five: discharging the battery with constant current of 0.5C until the voltage of the battery is 3.0U

Step six: standing the battery for 5 minutes;

step seven: repeating the steps from the first step to the sixth step for 500 cycles.

Example 1

The ambient temperature was 45 ℃.

And (3) charging and discharging processes:

the method comprises the following steps: charging the battery with a constant current of 1C until the voltage of the battery reaches 4.2V;

step two: charging the battery with a constant current of 0.8C until the voltage of the battery reaches a cut-off voltage of 4.3V;

step three: charging the battery with a constant current of 0.6C until the voltage of the battery reaches 4.4V;

step four: charging the battery with a constant voltage of 4.4V until the current of the battery reaches 0.4C;

step five: charging the battery with a constant current of 0.4C until the voltage of the battery reaches a cut-off voltage of 4.45V;

step six: continuously charging the battery by using the constant voltage of 4.45V until the current of the battery reaches the cutoff current of 0.13C;

step seven: standing the battery for 5 minutes;

step eight: discharging the battery by using a constant current of 0.5C until the voltage of the battery is 3.0U;

step nine: standing the battery for 5 minutes;

step ten: repeating the steps from the first step to the ninth step for 500 cycles.

Example 2

The ambient temperature was 45 ℃.

And (3) charging and discharging processes:

the method comprises the following steps: charging the battery with a constant voltage of 4V until the current of the battery reaches 0.9C;

step two: charging the battery with a constant voltage of 4.2V until the current of the battery reaches 0.7C;

step three: charging the battery with a constant voltage of 4.35V until the current of the battery reaches 0.5C;

step four: charging the battery with a constant current of 0.5C until the voltage of the battery reaches 4.4V;

step five: charging the battery with a constant voltage of 4.4V until the current of the battery reaches 0.3C;

step six: charging the battery with a constant current of 0.3C until the voltage of the battery reaches a cut-off voltage of 4.45V;

step seven: continuously charging the battery by using the constant voltage of 4.45V until the current of the battery reaches the cutoff current of 0.13C;

step eight: standing the battery for 5 minutes;

step nine: discharging the battery by using a constant current of 0.5C until the voltage of the battery is 3.0U;

step ten: standing the battery for 5 minutes;

step eleven: repeating the steps from one to ten 500 for circulation.

Example 3

The ambient temperature was 45 ℃.

And (3) charging and discharging processes:

the method comprises the following steps: charging the battery with a constant current of 0.7C until the voltage of the battery reaches 4.3V;

step two: charging the battery with a constant voltage of 4.3V until the current of the battery reaches a cut-off current of 0.5C;

step three: charging the battery with a constant current of 0.5C until the voltage of the battery reaches 4.4V;

step four: charging the battery with a constant voltage of 4.4V until the current of the battery reaches a cut-off current of 0.3C;

step five: charging the battery with a constant current of 0.3C until the voltage of the battery reaches a cut-off voltage of 4.45V;

step seven: standing the battery for 5 minutes;

step nine: standing the battery for 5 minutes;

Example 4

The ambient temperature was 45 ℃.

And (3) charging and discharging processes:

the method comprises the following steps: charging the battery with a constant power of 8W until the voltage of the battery reaches 4.3V;

step two: charging the battery with a constant power of 6.5W until the voltage of the battery reaches 4.4V;

step three: charging the battery with a constant voltage of 4.4V until the current of the battery reaches 0.5C;

step five: charging the battery with a constant current of 0.5C until the voltage of the battery reaches a cut-off voltage of 4.45V;

step seven: standing the battery for 5 minutes;

step nine: standing the battery for 5 minutes;

step ten: repeating the steps from one to eight for 500 cycles.

Example 5

The ambient temperature was 45 ℃.

And (3) charging and discharging processes:

the method comprises the following steps: standing the battery for 0.9 s;

step two: charging the battery for 9.1s by using a constant current of 0.7C, and jumping to a fourth step when the voltage of the battery is greater than or equal to 4.4V;

step three: repeating the first to third steps for 100000 cycles;

step four: discharging the battery for 1s with a constant current of 0.05C;

step five: charging the battery with a constant voltage of 4.4V until the current of the battery reaches 0.5C;

step six: charging the battery with a constant current of 0.5C until the voltage of the battery reaches a cut-off voltage of 4.45V;

step eight: standing the battery for 5 minutes;

step nine: repeating the steps from one to eight for 500 cycles.

The batteries of examples 1 to 5 and comparative examples 1 to 2 were tested for capacity retention rate and full charge time, and the test results were recorded in table 1 below. Capacity retention is provided by the following method test: the batteries of the comparative example and the example were cycled for 500 cycles using the corresponding charging procedure at an ambient temperature of 45 c, and the discharge capacity of the battery after 500 cycles was divided by the discharge capacity at 1 cycle to obtain the capacity retention ratio.

TABLE 1 test results of examples 1-5 and comparative examples 1-2

As can be seen from table 1, it can be seen from comparison between examples 1 to 5 and comparative example 1 that the charging method provided in the examples of the present application can maintain a higher capacity retention rate of the battery during the cycle use and can greatly shorten the time required for the battery to reach full charge compared to the prior art constant current and constant voltage charging method (i.e., comparative example 1). As can be seen from comparison between examples 1 to 5 and comparative example 2, the charging method provided in the present application can also maintain a higher capacity retention rate of the battery during the recycling process and can also greatly shorten the time required for the battery to reach the full charge compared to the charging method (i.e., comparative example 2) in the prior art, which increases the voltage during the constant voltage charging process.

Thus, the present application provides for charging a battery to a first phase voltage by at least one of constant current, constant voltage, or constant power during the first phase; and charging the battery to a second stage voltage in a second stage at least one of a constant current, a constant voltage, or a constant power. Alternatively, the first stage and the second stage may be a pulse charging or a pulse charging/discharging charging system. The charging method can optimize the early stage (first stage) of battery charging so as to reduce the early conventional charging time, reduce the risk of lithium precipitation, shorten the high potential time of the cathode, improve the cycle life of the battery core and improve the charging speed. And the charging voltage of the battery is increased from the first-stage voltage (namely, the charging limiting voltage) to the second-stage voltage, so that the charging speed of the battery in the charging process can be increased, and the total charging time can be shortened.

Referring to fig. 9, in this embodiment, the charging system 10 may be divided into one or more modules, and the one or more modules may be stored in the processor 11, and the processor 11 executes the charging method according to the embodiment of the present application. The one or more modules may be a series of computer program instruction segments capable of performing specific functions, which are used to describe the execution process of the charging system 10 in the electronic device 1. For example, the charging system 10 may be divided into a first charging module 101, a second charging module 102, and a third charging module 103 in fig. 9.

The first charging module 101 is configured to charge the battery to a first-stage voltage in a first charging manner or a second charging manner at a first stage; the second charging module 102 is configured to charge the battery to a second-stage voltage in a third charging manner at a second stage, where the second-stage voltage is greater than the first-stage voltage, and the third charging manner is the first charging manner or the second charging manner; the third charging module 103 is configured to perform constant-voltage charging on the battery at the second-stage voltage in a third stage.

The charging system 10 can perform charging management on the battery 12 to improve the charging efficiency of the battery and improve the high-temperature cycle life of the battery cell. For details, reference may be made to the above-mentioned embodiments of the battery charging method, and details thereof will not be described herein.

In an embodiment, the Processor 11 may be a Central Processing Unit (CPU), other general purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), an off-the-shelf Programmable Gate Array (FPGA) or other Programmable logic device, a discrete Gate or transistor logic device, a discrete hardware component, or the like. The general purpose processor may be a microprocessor or the processor 11 may be any other conventional processor or the like.

The modules of the charging system 10, if implemented in the form of software functional units and sold or used as separate products, may be stored in a computer readable storage medium. Based on such understanding, all or part of the flow in the method of the embodiments described above can be realized by a computer program, which can be stored in a computer-readable storage medium, and when the computer program is executed by a processor, the steps of the embodiments of the methods described above can be realized. Wherein the computer program comprises computer program code, which may be in the form of source code, object code, an executable file or some intermediate form, etc. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, usb disk, removable hard disk, magnetic disk, optical disk, computer Memory, Read-Only Memory (ROM), Random Access Memory (RAM), electrical carrier wave signals, telecommunications signals, software distribution medium, and the like. It should be noted that the computer readable medium may contain content that is subject to appropriate increase or decrease as required by legislation and patent practice in jurisdictions, for example, in some jurisdictions, computer readable media does not include electrical carrier signals and telecommunications signals as is required by legislation and patent practice.

It is understood that the above described module division is a logical function division, and there may be other division ways in actual implementation. In addition, functional modules in the embodiments of the present application may be integrated into the same processing unit, or each module may exist alone physically, or two or more modules are integrated into the same unit. The integrated module can be realized in a hardware form, and can also be realized in a form of hardware and a software functional module.

In another embodiment, the electronic device 1 may further include a memory (not shown), and the one or more modules may be stored in the memory and executed by the processor 11. The memory may be an internal memory of the electronic device 1, i.e. a memory built into the electronic device 1. In other embodiments, the memory may also be an external memory of the electronic device 1, i.e. a memory externally connected to the electronic device 1.

In some embodiments, the memory is used for storing program codes and various data, for example, program codes of the charging system 10 installed in the electronic device 1, and realizes high-speed and automatic access to programs or data during the operation of the electronic device 1.

The memory may include random access memory and may also include non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card), at least one magnetic disk storage device, a Flash memory device, or other non-volatile solid state storage device.

It will be evident to those skilled in the art that the present application is not limited to the details of the foregoing illustrative embodiments, and that the present application may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

1. a method for charging a battery, comprising:

In the first stage, the battery is charged to the voltage of the first stage by a first charging method or a second charging method, wherein the first charging method includes N charging sub-phases in sequence, and N is an integer greater than or equal to 2 , the N charging sub-phases are respectively defined as the i-th charging sub-phase, i=2, 3, . . . , N; in the i-th charging sub-phase one of them charges the battery; in the i+1 th charging sub-stage, the battery is charged with one of the i+1 th current, the i+1 th voltage and the i+1 th power; wherein , the charging current of the battery in the i+1th charging sub-stage is less than or equal to the charging current in the i-th charging sub-stage;

The second charging mode includes M charging sub-stages in sequence, where M is an integer greater than or equal to 2, and the M charging sub-stages are respectively defined as the j-th charging sub-stage, j=1, 2, ..., M , and each of the j-th charging sub-phases includes a j-th pre-charging sub-phase and a j-th post-charging sub-phase; in one of the j-th pre-charging sub-phase and the j-th post-charging sub-phase, for The battery is not charged or is charged or discharged at the j-th pre-charge sub-current for a period of Tj1; in the other of the j-th pre-charge sub-phase and the j-th post-charge sub-phase, the battery is charged with The jth post-charge sub-current is charged for a duration of Tj2; wherein the absolute value of the j-th pre-charge sub-current is less than the absolute value of the j-th post-charge sub-current; and

In the second stage, the battery is charged to a second stage voltage in a third charging mode, the second stage voltage is greater than the first stage voltage, wherein the third charging mode adopts the first charging mode or the The second charging method.

2 . The charging method according to claim 1 , wherein when the third charging mode adopts the first charging mode, the number N of charging sub-stages between the two is the same. 3 .

3 . The charging method according to claim 1 , wherein when the third charging method adopts the second charging method, the number M of charging sub-stages between the two is the same. 4 .

4 . The charging method of claim 1 , wherein the i+1 th voltage is greater than or equal to the i th voltage. 5 .

5 . The charging method of claim 1 , wherein the i+1 th power is less than or equal to the i th power. 6 .

6. The charging method according to claim 1, wherein the average value of the charging current in the j+1th charging sub-stage is less than or equal to the charging current in the j-th sub-stage, and when the third charging mode When the second charging mode is adopted, the average value of the charging current in the jth charging sub-stage is smaller than the charging current in the first charging mode or the second charging mode.

7 . The charging method of claim 1 , wherein the first-stage voltage is equal to the charging limit voltage of the battery, and the second-stage voltage is lower than the oxidative decomposition voltage of the electrolyte in the battery. 8 .

8. The charging method of claim 1, wherein the second stage voltage is less than or equal to the first stage voltage plus 500 mV.

9. The charging method of claim 1, wherein the method further comprises:

In the third stage, the battery is subjected to constant voltage charging at the second stage voltage.

10 . The charging method of claim 1 , wherein the charging current in the third charging mode is less than or equal to the charging current in the first charging mode or the second charging mode. 11 .

11. An electronic device, characterized in that the electronic device comprises:

batteries; and

The processor is configured to perform the charging method according to any one of claims 1 to 10 to charge the battery.

12. A storage medium having at least one computer instruction stored thereon, wherein the instruction is loaded by a processor and used to execute the charging method according to any one of claims 1 to 10.