Charging method and charging device

Abstract

The charging method comprises the steps that the terminal voltage of a battery is received, the terminal voltage is compared with an over-discharge threshold value and a limit threshold value, a first signal is output when the terminal voltage is smaller than the limit threshold value, a second signal is output when the terminal voltage is smaller than the over-discharge threshold value and larger than the limit threshold value, and the limit threshold value is smaller than the over-discharge threshold value; a first charging program is started according to the first signal, or a second charging program is started according to the second signal, the charging current of the first charging program is smaller than that of the second charging program, and the charging duration of the first charging program is larger than that of the second charging program.

Description

Technical Field

[0001] This invention relates to the field of lithium battery charging technology, and more specifically to a charging method and a charging device. Background Technology

[0002] Lithium-ion batteries stored for extended periods may experience over-discharge due to their self-discharge process. Once this occurs, the battery needs to be recharged and activated until it returns to its nominal voltage and normal chemical properties before it can be used again. However, continuing to use the original charging method or a high-current activation charging method after over-discharge will accelerate battery failure; while using only ordinary trickle charging will result in a very long charging time, failing to meet the need for rapid battery use. Therefore, the key is to find a way to both ensure activation of over-discharged batteries and meet the requirement for rapid battery activation. Summary of the Invention

[0003] The purpose of this invention is to provide a charging method and a charging device that can balance the protection activation requirements and the rapid activation requirements of over-discharged battery charging.

[0004] To achieve the objectives of this invention, the following technical solution is provided: In a first aspect, the present invention provides a charging method, comprising: receiving a battery terminal voltage; comparing the terminal voltage with an over-discharge threshold and a limit threshold; outputting a first signal when the terminal voltage is less than the limit threshold; and outputting a second signal when the terminal voltage is less than the over-discharge threshold and greater than the limit threshold, wherein the limit threshold is less than the over-discharge threshold; initiating a first charging program according to the first signal, or initiating a second charging program according to the second signal, wherein the charging current of the first charging program is less than the charging current of the second charging program, and the charging duration of the first charging program is greater than the charging duration of the second charging program.

[0005] In some implementations, the over-discharge threshold is any fixed value between 2V and 3.5V, and the limiting threshold is any fixed value between 0.1V and 2V.

[0006] In some embodiments, the first charging program includes a first charging subroutine and a second charging subroutine. Activating the first charging program based on the first signal includes: when the material characteristics of the battery are determined, activating the first charging subroutine based on the first signal and the material characteristics of the battery; or, when the material characteristics of the battery are missing, activating the second charging subroutine based on the first signal.

[0007] In some embodiments, when the material properties of the battery are determined, the material properties of the battery include the particle size D50 and solid-phase diffusion coefficient of the negative electrode material; the first charging subroutine satisfies: L = (D × t0) ^0.5 Wherein, L is the particle size D50 of the negative electrode material in the battery, D is the solid-phase diffusion coefficient of the negative electrode material in the battery, and t0 is the diffusion time of lithium ions in the battery.

[0008] In some implementations, the first charging subroutine further satisfies: I1 = Q1 / t0, and t1 ≥ t0; where I1 is the charging current in the first charging subroutine, Q1 is the charging charge in the first charging subroutine, and t1 is the charging time in the first charging subroutine.

[0009] In some embodiments, when the material properties of the battery are lacking, the second charging subroutine satisfies: I2≤Q2 / t2, and t2≥50h; where I2 is the charging current in the second charging subroutine, Q2 is the charging charge in the second charging subroutine, and t2 is the charging time in the second charging subroutine.

[0010] In some implementations, after the first charging process is completed, the battery is cyclically charged using a first charging rate, wherein the first charging rate is less than or equal to 0.3C.

[0011] In some embodiments, the second charging procedure includes: pulse charging the battery at a second charging rate less than or equal to 0.5C to activate the battery.

[0012] In some embodiments, the second charging procedure further includes: cyclically charging the activated battery using a third charging rate less than or equal to 0.5C, wherein the number of cyclic charging cycles is 2 to 3.

[0013] Secondly, the present invention provides a charging device for charging a battery, comprising a detection module, a control module, and a charging module; wherein the detection module is used to detect the terminal voltage of the battery; the control module is electrically connected to the detection module, and is used to receive the terminal voltage and compare the terminal voltage with an over-discharge threshold and a limit threshold; when the terminal voltage is less than the limit threshold, the control module outputs a first signal; when the terminal voltage is less than the over-discharge threshold and greater than the limit threshold, the control module outputs a second signal, wherein the limit threshold is less than the over-discharge threshold; the charging module is electrically connected to the control module, and is used to initiate a first charging program according to the first signal, or, according to the second signal, initiate a second charging program, wherein the charging current of the first charging program is less than the charging current of the second charging program, and the charging duration of the first charging program is greater than the charging duration of the second charging program.

[0014] This invention provides a charging method for over-discharge protection of lithium-ion batteries. The method receives the battery's terminal voltage and compares it with an over-discharge threshold and a limit threshold. Once the over-discharge voltage is determined to be within the range of the over-discharge threshold or the limit threshold, a corresponding first signal and a second signal are output. The first or second signal is used to initiate a corresponding first charging program or a second charging program, thereby selectively charging the battery. In cases of extreme battery discharge, the first charging program is initiated first to charge with a small current to meet the battery protection requirements. When the battery discharge exceeds the limit threshold, the second charging program is initiated to charge with a larger current to meet the requirement of rapid battery activation. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, 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 the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 This is a flowchart of one implementation method for charging; Figure 2 This is a schematic diagram of signal transmission for one implementation of a charging method; Figure 3 This is a flowchart of another implementation of a charging method; Figure 4 This is a flowchart of another implementation method for charging; Figure 5 This is a schematic diagram of a charging device according to one embodiment. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] It should be noted that when a component is said to be "fixed" to another component, it can be directly on the other component or it can be in a middle component. When a component is said to be "connected" to another component, it can be directly connected to the other component or it may be in a middle component.

[0019] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used in this invention includes any and all combinations of one or more of the associated listed items.

[0020] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0021] This invention provides a charging method for over-discharge protection of lithium-ion batteries. Please refer to [the relevant documentation]. Figure 1 and Figure 2 Specifically, it includes the following steps: Step S100: Receive the battery terminal voltage, compare the terminal voltage with the over-discharge threshold and the limit threshold, output a first signal when the terminal voltage is less than the limit threshold, and output a second signal when the terminal voltage is less than the over-discharge threshold and greater than the limit threshold, wherein the limit threshold is less than the over-discharge threshold. Step S200: Start a first charging program according to the first signal, or start a second charging program according to the second signal, wherein the charging current of the first charging program is less than the charging current of the second charging program, and the charging time of the first charging program is greater than the charging time of the second charging program.

[0022] In a specific embodiment, the charging method provided by this invention is a method for recharging and activating lithium-ion batteries after over-discharge. Over-discharge of a lithium battery refers to an abnormal state in which the discharge voltage is lower than its minimum protection voltage or the discharge capacity exceeds its rated capacity during use. After over-discharge, the degree of lithium ion depletion in the graphite is high, with some graphite anodes in the H1 phase, resulting in reduced interlayer spacing. Lithium ion re-intercalation requires overcoming the resistance of interlayer transitions during phase transitions, which is significant. If ordinary high-current charging is used directly, lithium plating will occur, severely affecting the battery's capacity retention and lifespan.

[0023] In specific embodiments, the charging method provided by this invention can be used in wireless charging systems, specifically for implementing wireless charging protection. It should be noted that most conventional mobile devices have integrated batteries, meaning the batteries are not removable and are housed within the device. Furthermore, with the development of wireless charging technology, there are few solutions for recharging and activating over-discharged batteries in the wireless charging field. Therefore, the charging method provided by this invention can be applied to wireless charging solutions where it is impossible to recharge and activate the battery separately.

[0024] In a specific embodiment, step S001 may be included before step S100, in which the battery terminal voltage is acquired and transmitted. Specifically, the acquisition method may involve electrically connecting the positive and negative terminals of the battery to a module used for acquiring the terminal voltage, and this module can monitor the battery terminal voltage in real time. This module can then send the acquired terminal voltage to the module in step S100 for further processing.

[0025] In a specific embodiment, in step S100, the over-discharge threshold refers to the minimum protection voltage of the battery in the above embodiment. When the battery's terminal voltage is lower than the over-discharge threshold, it indicates that the battery is in a state of over-discharge. When the battery's terminal voltage is higher than the over-discharge threshold, it indicates that the battery is in a normal state, i.e., there is no over-discharge. When the battery's terminal voltage is higher than the over-discharge threshold, a third signal is output. The third signal is used to start a third charging program, which is a normal charging program. The charging rate of the third charging program can be greater than or equal to 0.5C, i.e., the charging time is less than or equal to 2 hours.

[0026] In a specific embodiment, in step S100, the limit threshold refers to the voltage value below the over-discharge threshold. When the battery's terminal voltage is below the limit threshold, it indicates that the battery is in a state of extreme discharge. The interlayer spacing between the negative electrode graphite layers is too narrow, which worsens the activation effect of conventional low-current charging and leads to a decrease in the activated battery capacity. Therefore, this application sets a first signal to start the first charging procedure when the voltage is below the over-discharge threshold.

[0027] In a specific embodiment, in step S200, the first charging program and the second charging program are two different protective charging programs, both of which are used to perform protective charging after the battery has been over-discharged. Specifically, the first charging program has a smaller charging current (smaller charging rate) and a longer charging time; the second charging program has a larger charging current (larger charging rate) and a shorter charging time.

[0028] In a specific embodiment, step S200 may include a trickle charging process, where the trickle charging current is extremely small, typically much lower than the conventional charging current, generally between 0.01C and 0.1C (e.g., for a 2Ah battery, the trickle current is only 20mA-200mA). The second charging process may include a pulse charging process, which is a method of charging with intermittent current through alternating cycles of "charging-pause" or "charging-discharging".

[0029] In other embodiments, in step S200, a first charging program can also be started according to the second signal, that is, when the battery terminal voltage is between the over-discharge threshold and the limit threshold, the first charging program can also be used for charging; that is, a low current (low rate) scheme is used to charge and activate the battery.

[0030] This invention provides a charging method for over-discharge protection of lithium-ion batteries. The method receives the battery's terminal voltage and compares it with an over-discharge threshold and a limit threshold. Once the over-discharge voltage is determined to be within the range of the over-discharge threshold or the limit threshold, a corresponding first signal and a second signal are output. The first or second signal is used to initiate a corresponding first charging program or a second charging program, thereby selectively charging the battery. In cases of extreme battery discharge, the first charging program is initiated first to charge with a small current to meet the battery protection requirements. When the battery discharge exceeds the limit threshold, the second charging program is initiated to charge with a larger current to meet the requirement of rapid battery activation.

[0031] In some embodiments, the over-discharge threshold is any fixed value between 2V and 3.5V. Optionally, the over-discharge threshold can be 2V, 2.1V, 2.2V, 2.3V, 2.4V, 2.5V, 2.6V, 2.7V, 2.8V, 2.9V, 3V, 3.1V, 3.2V, 3.3V, 3.4V, or 3.5V. The solution provided in this application can be applied to lithium batteries with different cathode materials, such as lithium iron phosphate batteries, ternary lithium batteries, and lithium cobalt oxide batteries, and the over-discharge threshold can be different for different cathode material lithium batteries.

[0032] In a specific embodiment, when the lithium-ion battery is a lithium iron phosphate battery, the over-discharge threshold is 2V~3V; when the lithium-ion battery is a ternary lithium battery, the over-discharge threshold is 2.5V~3V; and when the lithium-ion battery is a lithium cobalt oxide battery, the over-discharge threshold is 2.5V~3.5V.

[0033] In a specific embodiment, in step S001, while acquiring the battery's terminal voltage, the type of the positive electrode material in the battery can also be acquired, and an electrical signal containing the positive electrode material type is emitted together with the terminal voltage. Step S100 further includes receiving the electrical signal containing the positive electrode material type and providing a corresponding over-discharge threshold based on the electrical signal.

[0034] In a specific embodiment, in step S001, the emitted electrical signal indicating the type of positive electrode material includes one of a first type of electrical signal, a second type of electrical signal, and a third type of electrical signal, each of which corresponds to a different positive electrode material. In step S001, the provided over-discharge threshold includes one of a first over-discharge threshold, a second over-discharge threshold, and a third over-discharge threshold, each of which corresponds to the actual over-discharge voltage value of a different positive electrode material.

[0035] In some implementations, the over-discharge threshold is any fixed value between 0.1V and 2V. Optionally, the over-discharge threshold is 0.1V, 0.2V, 0.4V, 0.6V, 0.8V, 1V, 1.2V, 1.4V, 1.6V, 1.8V, or 2V. The over-discharge threshold can be the same for lithium batteries with different cathode materials. Setting the over-discharge threshold within the above range is to establish a lower limit for over-discharge. Below this threshold, the battery is severely over-discharged, the interlayer spacing of the anode material is smaller, the battery is more suitable for trickle charging for slow activation, and the anode material can slowly intercalate lithium to avoid lithium dendrite formation.

[0036] In some implementations, the first charging procedure includes a first charging subroutine and a second charging subroutine. Activating the first charging procedure based on a first signal includes: when the material characteristics of the battery are determined, activating the first charging subroutine based on the first signal and the material characteristics of the battery; or, when the material characteristics of the battery are missing, activating the second charging subroutine based on the first signal.

[0037] In a specific embodiment, step S200 may include two trickle charging processes: a first charging subroutine and a second charging subroutine. Specifically, when the battery's material characteristics are determined, the first charging subroutine can be used to charge and activate the battery; when the battery's material characteristics are not determined, the second charging subroutine can be used to charge and activate the battery.

[0038] In a specific embodiment, in step S200, the first charging subroutine can utilize the material characteristics of the battery to calculate the precise charging time and charging current, thereby determining the time when charging activation is complete. For example, conventional mobile devices typically display the charging time or the time when charging is complete. With the charging method provided by this invention, the mobile device can provide the user with the calculated charging time.

[0039] In a specific embodiment, in step S200, the second charging subroutine can calculate the charging current based on a preset charging time, thereby controlling the battery to maintain trickle charging. Furthermore, this program is universally applicable and can meet the charging activation requirements of most batteries, even when the battery's material properties are unknown.

[0040] In some implementations, when the material properties of the battery are determined, these properties include the particle size D50 of the negative electrode material and the solid-phase diffusion coefficient; the first charging subroutine satisfies: L = (D × t0) ^0.5 Where L is the particle size D50 of the negative electrode material in the battery, in μm; D is the solid-phase diffusion coefficient of the negative electrode material in the battery, in cm / s; and t0 is the diffusion time of lithium ions in the battery, in s.

[0041] In a specific embodiment, the charging efficiency of the battery is related to the ion transport efficiency of the electrode material. The solid-phase diffusion coefficient D reflects the ease with which ions move within a solid material and is an inherent property of the material. Once the particle size and solid-phase diffusion coefficient of the negative electrode material in the battery are determined, the diffusion time of lithium ions in the battery can be calculated.

[0042] This invention sets the charging time according to the material characteristics of different batteries by setting the first charging subroutine to satisfy the above relationship. This ensures that ions can be embedded into the negative electrode material instead of being bound to the outside of the negative electrode material to form lithium dendrites, thereby increasing the battery cycle capacity retention rate.

[0043] In some implementations, the first charging subroutine also satisfies: I1 = Q1 / t0, and t1 ≥ t0; where I1 is the charging current in the first charging subroutine, Q1 is the charging charge in the first charging subroutine, and t1 is the charging time in the first charging subroutine.

[0044] In a specific embodiment, the lithium ion diffusion time t0 can be used as the minimum charging time for battery charging activation. Given the material properties of the battery, the battery charging time t1 should not be less than the lithium ion diffusion time t0, and the charging current can be determined to ensure that trickle charging provides charging protection for the battery.

[0045] In some implementations, when the material properties of the battery are lacking, the second charging subroutine satisfies: I2≤Q2 / t2, and t2≥50h; where I2 is the charging current in the second charging subroutine, Q2 is the charging charge in the second charging subroutine, and t2 is the charging time in the second charging subroutine.

[0046] In a specific embodiment, the charging duration t2 in the second charging subroutine can be a preset time, specifically 50h≤t2≤100h. After determining the charging duration t2 in the second charging subroutine, the charging current I2 in the second charging subroutine can be determined according to the above relationship, thereby achieving constant current charging until the battery is activated and can be used normally.

[0047] Understandably, when the material properties of the battery cannot be determined, in order to avoid the charging process from affecting the battery, a more suitable charging time can be set in advance, and the corresponding charging current can be determined according to the charging time, thereby increasing the battery cycle capacity retention rate and expanding the applicability of the charging method.

[0048] In some implementations, after the first charging cycle is completed, the battery is cycle-charged at a first charging rate less than or equal to 0.3C. Specifically, by performing low-rate cycle-charging protection on the activated battery, the wear and tear on the battery during the charging process can be minimized while maintaining basic charging efficiency.

[0049] In some implementations, the second charging procedure includes: pulse charging the battery at a second charging rate less than or equal to 0.5C to activate the battery. Specifically, the "pause" or "reverse small discharge" phase of the pulse charging allows ions to diffuse fully, reducing polarization and thus allowing for subsequent charging with a larger current, achieving a balance between fast charging and protection.

[0050] In some embodiments, the second charging procedure further includes: cyclically charging the activated battery using a third charging rate less than or equal to 0.5C, with the number of charge cycles being 2 to 3. Specifically, after pulse charging, 2 to 3 charges are performed, always maintaining a constant current charge rate less than or equal to 0.5C. Optionally, the second charging rate can be less than or equal to 0.3C, and the third charging rate can be greater than 0.3C but less than or equal to 0.5C.

[0051] In some implementations, during the battery charging and activation process using this charging method, a first charging procedure and a second charging procedure can be sequentially performed to charge and activate the battery. Please refer to [reference needed]. Figure 3 Specifically, it includes the following steps: Step S101: Receive the first terminal voltage of the battery, and output a first signal when the first terminal voltage is less than the limit threshold. Step S201: Start the first charging subroutine based on the first signal and the material characteristics of the battery; or, if the material characteristics of the battery are missing, start the second charging subroutine based on the first signal. Step S301: Receive the second terminal voltage of the battery; when the second terminal voltage is less than the over-discharge threshold and greater than the limit threshold, output the second signal. Step S401: Start the second charging program according to the second signal, and use the second charging rate to pulse charge the battery to activate the battery.

[0052] In a specific embodiment, when the initial terminal voltage (first terminal voltage) of the battery is less than the limit threshold, the battery can be trickled charged using a first charging program (first charging subroutine or second charging subroutine) to protect the over-discharged battery as much as possible; then, after the battery reaches the second terminal voltage, the battery is pulse-charged using a second charging program to improve charging efficiency and reduce charging time.

[0053] In some implementations, during the battery activation process using this charging method, a first charging procedure and a second charging procedure can be sequentially used to activate the battery, followed by a third charging procedure for normal charging. Please refer to [reference needed]. Figure 4 Specifically, it includes the following steps: Step S101: Receive the first terminal voltage of the battery, and output a first signal when the first terminal voltage is less than the limit threshold. Step S201: Start the first charging subroutine based on the first signal and the material characteristics of the battery; or, if the material characteristics of the battery are missing, start the second charging subroutine based on the first signal. Step S301: Receive the second terminal voltage of the battery; when the second terminal voltage is less than the over-discharge threshold and greater than the limit threshold, output the second signal. Step S401: Start the second charging program according to the second signal, and use the second charging rate to pulse charge the battery to activate the battery; Step S501: Receive the third terminal voltage of the battery; when the third terminal voltage is greater than the over-discharge threshold, output the third signal. Step S601: Start the third charging program according to the third signal, and charge the battery with constant voltage and constant current using the conventional rate.

[0054] In a specific embodiment, the third charging procedure can refer to the above embodiment. When the battery terminal voltage reaches or exceeds the over-discharge threshold, the battery can be charged at a constant voltage and constant current rate using a conventional rate, thereby further improving charging efficiency and meeting the needs of users who urgently require batteries.

[0055] For some implementation methods, please refer to Figure 5 The present invention also provides a charging device that charges a battery using the charging method provided in the above embodiments. The charging device includes a detection module, a control module, and a charging module. The detection module is used to detect the battery's terminal voltage. The control module is electrically connected to the detection module and is used to receive the terminal voltage and compare it with an over-discharge threshold and a limit threshold. When the terminal voltage is less than the limit threshold, a first signal is output; when the terminal voltage is less than the over-discharge threshold but greater than the limit threshold, a second signal is output, where the limit threshold is less than the over-discharge threshold. The charging module is electrically connected to the control module and is used to initiate a first charging program based on the first signal, or to initiate a second charging program based on the second signal. The charging current of the first charging program is less than the charging current of the second charging program, and the charging duration of the first charging program is greater than the charging duration of the second charging program.

[0056] In a specific embodiment, the detection module is connected to the positive and negative terminals of the battery and is used to monitor the battery's terminal voltage in real time. The detection module also needs to send the detected terminal voltage to the control module. The control module is electrically connected to the detection module, and the control module can be configured to output a first signal or a second signal when the terminal voltage is lower than an over-discharge threshold. The charging module is electrically connected to the battery and the control module. The control module receives the first signal or the second signal and, in response to the electrical signal, initiates the corresponding charging program for protective activation charging.

[0057] In a specific embodiment, the detection module can also be used to detect the material characteristics of the battery, and after detecting the material characteristics, send the detected material characteristics to the control module. Alternatively, the battery material characteristics can be recorded in the control module, and the control module outputs the material characteristics to the charging module simultaneously with the output of the electrical signal. It is understood that recording the battery material characteristics in the control module can satisfy the matching scheme between the charging device and the battery, that is, the battery to be activated for charging is specifically paired with the charging device.

[0058] This invention provides a charging device for over-discharge protection of lithium-ion batteries. The charging device obtains the battery's terminal voltage through a detection module electrically connected to the battery. The control module receives the battery's terminal voltage and compares it with an over-discharge threshold and a limit threshold, thus determining whether the battery's over-discharge voltage is within the range of the over-discharge threshold or the limit threshold. The control module outputs a first signal or a second signal to the charging module, which can correspondingly activate a first charging program or a second charging program to selectively charge the battery. In the case of extreme battery discharge, the first charging program can be activated first to charge with a small current to meet the battery protection requirements. When the battery discharge exceeds the limit threshold, the second charging program can be activated to charge with a larger current to meet the requirements of rapid battery activation.

[0059] In the description of the embodiments of the present invention, it should be noted that the orientation or positional relationship of the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and other indicators are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and are not intended to 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 the present invention.

[0060] The above description discloses only one preferred embodiment of the present invention, and should not be construed as limiting the scope of the present invention. Those skilled in the art will understand that all or part of the processes of the above embodiments can be implemented, and equivalent changes made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A charging method, characterized in that, include: The terminal voltage of the battery is received, and the terminal voltage is compared with an over-discharge threshold and a limit threshold. When the terminal voltage is less than the limit threshold, a first signal is output. When the terminal voltage is less than the over-discharge threshold and greater than the limit threshold, a second signal is output. The limit threshold is less than the over-discharge threshold. The first charging program is started according to the first signal, or the second charging program is started according to the second signal, wherein the charging current of the first charging program is less than the charging current of the second charging program, and the charging time of the first charging program is greater than the charging time of the second charging program.

2. The charging method according to claim 1, characterized in that, The over-discharge threshold is any fixed value between 2V and 3.5V, and the limiting threshold is any fixed value between 0.1V and 2V.

3. The charging method according to claim 1, characterized in that, The first charging program includes a first charging subroutine and a second charging subroutine. Activating the first charging program based on the first signal includes: When the material properties of the battery are determined, a first charging subroutine is started based on the first signal and the material properties of the battery; or, when the material properties of the battery are missing, a second charging subroutine is started based on the first signal.

4. The charging method according to claim 3, characterized in that, When the material properties of the battery are determined, the material properties of the battery include the particle size D50 and the solid-phase diffusion coefficient of the negative electrode material; the first charging subroutine satisfies: L = (D × t0) ^0.5 Wherein, L is the particle size D50 of the negative electrode material in the battery, D is the solid-phase diffusion coefficient of the negative electrode material in the battery, and t0 is the diffusion time of lithium ions in the battery.

5. The charging method according to claim 4, characterized in that, The first charging subroutine also satisfies: I1=Q1 / t0, and t1≥t0; where I1 is the charging current in the first charging subroutine, Q1 is the charging charge in the first charging subroutine, and t1 is the charging time in the first charging subroutine.

6. The charging method according to claim 3, characterized in that, When the material properties of the battery are missing, the second charging subroutine satisfies: I2≤Q2 / t2, and t2≥50h; where I2 is the charging current in the second charging subroutine, Q2 is the charging charge in the second charging subroutine, and t2 is the charging time in the second charging subroutine.

7. The charging method according to any one of claims 1-6, characterized in that, After the first charging procedure is completed, the battery is cyclically charged using a first charging rate, wherein the first charging rate is less than or equal to 0.3C.

8. The charging method according to claim 1, characterized in that, The second charging procedure includes: performing pulse charging on the battery at a second charging rate to activate the battery, wherein the second charging rate is less than or equal to 0.5C.

9. The charging method according to claim 8, characterized in that, The second charging procedure further includes: cyclically charging the activated battery using a third charging rate less than or equal to 0.5C, and the number of cyclic charging cycles being 2 to 3.

10. A charging device for charging a battery, characterized in that, include: A detection module is used to detect the terminal voltage of the battery; A control module is electrically connected to the detection module. The control module is used to receive the terminal voltage and compare the terminal voltage with an over-discharge threshold and a limit threshold. When the terminal voltage is less than the limit threshold, a first signal is output. When the terminal voltage is less than the over-discharge threshold and greater than the limit threshold, a second signal is output. The limit threshold is less than the over-discharge threshold. A charging module is electrically connected to the control module. The charging module is used to start a first charging program according to the first signal, or to start a second charging program according to the second signal. The charging current of the first charging program is less than the charging current of the second charging program, and the charging time of the first charging program is greater than the charging time of the second charging program.

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