Battery maintenance method

Abstract

The invention provides a battery maintenance method. The battery maintenance method comprises the following steps: providing an aged battery; the aged battery is subjected to multiple times of cyclic charging and discharging, and at least one of charging and discharging adopts direct current bias current to be superposed with alternating current. According to the battery maintenance method provided by the invention, the composite current formed by superposing the bias direct current and the specific high-frequency alternating current is applied to the aged battery, and the internal interface film of the aged battery is optimized through the high-frequency alternating current, so that the impedance of the battery is reduced, the bad thickening of the battery is inhibited, and the aging of the battery can be effectively delayed; the performance of the battery lost due to the interface problem is maintained and partially recovered, and the maintenance effect of prolonging the overall service life of the battery is finally achieved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery maintenance method. Background Art

[0002] Battery applications are becoming increasingly widespread and expanding. Take lithium batteries, for example. As one of the most widely used batteries, lithium batteries rely primarily on the movement of lithium ions between positive and negative electrodes to charge and discharge. However, as batteries continue to age, they are affected by various factors, ultimately manifesting as capacity loss, increased internal resistance, and decreased safety.

[0003] To address the issue of lithium battery aging maintenance, researchers have often adopted a more intelligent battery management system (BMS) during battery use. While BMSs can mitigate battery aging through dynamic control, the nonlinear characteristics of aging batteries often affect data accuracy and algorithm reliability. Active repair methods, such as restoring battery capacity to extend battery life, have also been used to mitigate battery aging. Some researchers have explored innovative battery materials to mitigate aging, but this often involves high costs and complex manufacturing processes. Others have also adopted electrolyte replacement, but this remains costly. Meanwhile, some researchers have used shallow charge and discharge cycles to restore battery capacity and maintain battery performance. However, this approach fails to alter the chemical composition and structure of the internal interface membranes after aging, involves multivariable parameter adjustments, and is complex to integrate and implement. Furthermore, without precise control algorithms, shallow charge and discharge cycles can easily cause cumulative damage to key components within the battery, such as the electrode surface layer, active material microstructure, and electrolyte distribution, exacerbating battery aging.

[0004] Based on this, it is necessary to provide a more effective and reliable technical solution to alleviate the problem of lithium battery aging. Summary of the Invention

[0005] The present application provides a battery maintenance method that can effectively delay battery aging, maintain and partially restore the battery performance lost due to interface problems, and ultimately achieve the maintenance effect of extending the overall battery service life.

[0006] The present application provides a battery maintenance method, comprising: providing an aged battery; and performing multiple cycles of charging and discharging on the aged battery, wherein at least one of the charging and discharging uses a DC bias current superimposed on an AC current.

[0007] In some embodiments of the present application, the remaining capacity of the aged battery is 95% or less of its factory rated capacity, where the remaining capacity of the battery is the total amount of electricity that can be released by the battery in the current state.

[0008] In some embodiments of the present application, the frequency of the alternating current is 1K to 1 MHz, the rate of the cyclic charge and discharge is 0.1C to 1C, and the number of cyclic charge and discharge is 1 to 10 times.

[0009] In some embodiments of the present application, the frequency of the alternating current, the rate of the cyclic charging and discharging, and the number of the cyclic charging and discharging are set according to the remaining capacity of the aged battery.

[0010] In some embodiments of the present application, the higher the remaining capacity of the aged battery, the lower the frequency of the alternating current; the higher the remaining capacity of the aged battery, the higher the rate of the cyclic charge and discharge; and the higher the remaining capacity of the aged battery, the fewer the number of cyclic charge and discharge.

[0011] In some embodiments of the present application, when the remaining capacity of the aged battery is 80% to 95% of the factory rated capacity of the aged battery, the frequency of the alternating current is 1K to 1 MHz, the rate of the cyclic charge and discharge is 0.1C to 1C, and the number of cyclic charge and discharge is 3 to 5 times.

[0012] In some embodiments of the present application, when the remaining capacity of the aged battery is 60% to 80% of the factory rated capacity of the aged battery, the frequency of the alternating current is 1K to 1 MHz, the rate of the cyclic charge and discharge is 0.1C to 0.9C, and the number of cyclic charge and discharge is 5 to 8 times.

[0013] In some embodiments of the present application, when the remaining capacity of the aged battery is less than 60% of the factory rated capacity of the aged battery, the frequency of the alternating current is 1K to 1 MHz, the rate of the cyclic charge and discharge is 0.1C to 0.8C, and the number of cyclic charge and discharge is 8 to 10 times.

[0014] In some embodiments of the present application, both the charging and discharging are performed by superimposing a DC bias current on an AC current.

[0015] In some embodiments of the present application, performing multiple cycles of charging and discharging on the aged battery includes: charging the aged battery to a charge cutoff voltage and then discharging it to 0% SOC; and repeating the above steps.

[0016] The present application provides a battery maintenance method. By applying a composite current consisting of biased DC and specific high-frequency AC to an aging battery, the structure and performance of the SEI film are gently regulated in a microscopic electrochemical perturbation manner to reduce its impedance and inhibit its undesirable thickening. This can effectively delay battery aging, maintain and partially restore the battery performance lost due to interface problems, and ultimately achieve the maintenance effect of extending the overall battery service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The following figures describe in detail exemplary embodiments disclosed in this application. Like reference numerals denote similar structures throughout the several views of the drawings. Those skilled in the art will appreciate that these embodiments are non-limiting, exemplary embodiments, and that the drawings are provided for illustration and description purposes only and are not intended to limit the scope of this application. Other embodiments may also achieve the inventive intent of this application. It should be understood that the drawings are not drawn to scale.

[0018] in:

[0019] Figure 1 This is a flowchart of the maintenance method described in some embodiments of the present application. DETAILED DESCRIPTION

[0020] The following description provides specific application scenarios and requirements of the present application, with the purpose of enabling those skilled in the art to make and use the content of this application. Various local modifications to the disclosed embodiments will be apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of this application. Therefore, this application is not limited to the embodiments shown, but is intended to be of the widest scope consistent with the claims.

[0021] The technical solution of the present invention is described in detail below with reference to the embodiments and drawings.

[0022] To address the issues of reduced capacity and safety caused by battery aging, this application provides a new battery maintenance method. Its core purpose is to provide a technical solution that can actively, gently, and precisely maintain battery health, especially optimizing the state of the SEI membrane. Specifically, by applying a composite current consisting of a biased DC and a specific high-frequency AC to the battery, the method aims to gently regulate the structure and properties of the SEI membrane through microscopic electrochemical perturbations, reducing its impedance and inhibiting its undesirable thickening, thereby effectively delaying battery aging, maintaining and partially restoring the battery's performance lost due to interface problems, and ultimately achieving a maintenance effect that extends the battery's overall service life.

[0023] Figure 1 This is a flowchart of the maintenance method described in some embodiments of the present application.

[0024] refer to Figure 1 As shown, the present application provides a battery maintenance method, comprising: step S1: providing an aged battery; step S2: performing multiple cycles of charging and discharging on the aged battery, wherein at least one of the charging and discharging uses a DC bias current superimposed on an AC current.

[0025] Step S1: Providing an aged battery. With continued use, batteries can be affected by various factors (such as irregular structure, excessive thickness, or an SEI film that increases interfacial resistance), leading to battery aging, ultimately manifesting as capacity decay, increased internal resistance, and decreased safety. The technical solution of this application is primarily targeted at aged batteries that, after a period of use, experience SEI film problems, leading to battery aging and capacity decay. Specifically, in some embodiments of this application, the remaining capacity of the aged battery is 95% or less of its factory rated capacity. The factory rated capacity of a battery refers to the maximum dischargeable capacity of a brand new battery, as measured by the manufacturer under standard testing conditions. For example, a battery with a factory rated capacity of 700 mAh may, after a period of use, decrease to 90% (630 mAh) due to aging. This application addresses this type of aged battery. Generally speaking, the capacity of a new battery will begin to decrease to some extent upon initial use. However, for batteries with a high SOH (capacity above 95%), the capacity decrease is not significant, and battery maintenance is not effective or necessary at this time. Therefore, this application is mainly aimed at batteries with a certain degree of aging (capacity less than 95%).

[0026] Step S2, performing multiple cycles of charging and discharging on the aged battery, wherein at least one of the charging and discharging uses a DC bias current superimposed on an AC current.

[0027] The applicant has experimentally discovered that applying a biased DC current superimposed with an AC current to an aged battery due to problems with the SEI membrane for high-frequency charging and discharging can affect the key interfaces within the battery, especially the SEI (solid electrolyte interface) membrane, which is crucial in systems such as ion batteries, thereby producing a significant and positive regulatory effect. Under the action of a high-frequency (1kHz-1MHz) electric field, this method can partially dissolve and favorably redeposit the organic or inorganic components that cause the SEI membrane in the aged battery (such as an irregular structure, excessive thickness, or an SEI membrane that causes increased interfacial resistance), thereby repairing it and forming a more uniform and denser protective layer. In addition, by repairing and optimizing the SEI membrane, it can effectively clear ion transport channels that are blocked by byproducts or become tortuous due to membrane thickening, significantly reducing the migration resistance of ions when passing through the SEI membrane, improving the electrochemical reaction kinetics of the battery, and restoring the battery capacity to a certain extent. The method has strong parameter adjustability and can meet the capacity recovery needs of aged batteries in different systems and environments, increasing battery capacity and thus extending battery service life. Based on this principle, the present application can achieve maintenance of aging batteries through the above-mentioned step 2. By means of microscopic electrochemical perturbations, the structure and performance of the SEI film can be gently regulated, its impedance can be reduced, its undesirable thickening can be inhibited, the aging of the battery can be effectively delayed, and the performance of the battery lost due to interface problems can be maintained and partially restored, ultimately achieving the maintenance effect of extending the overall service life of the battery.

[0028] In some embodiments of the present application, at least one of charging and discharging using a DC bias current superimposed on an AC current includes: charging using DC current and discharging using a DC bias current superimposed on an AC current; charging using a DC bias current superimposed on an AC current and discharging using a DC bias current superimposed on an AC current; or charging using a DC bias current superimposed on an AC current and discharging using a DC bias current. Preferably, charging uses a DC bias current superimposed on an AC current.

[0029] In some embodiments of the present application, performing multiple cycles of charging and discharging on the aged battery includes: charging the aged battery to a charge cutoff voltage and then discharging it to 0% SOC; and repeating the above steps.

[0030] In some embodiments of the present application, the frequency of the alternating current is 1K to 1MHz, such as 1KHz, 2KHz, 3KHz, 5KHz, 8KHz, 10KHz, 20KHz, 50KHz, etc. The rate of the cyclic charge and discharge is 0.1C to 1C, such as 0.1C, 0.2C, 0.3C, 0.4C, 0.5C, 0.6C, 0.7C, etc. The number of cyclic charge and discharge times is 1 to 10 times, such as 2 times, 3 times, 4 times, 5 times, 6 times, 7 times, 8 times, 9 times, etc.

[0031] In some embodiments of the present application, the instantaneous total current after the DC bias current is superimposed on the AC current must be within the safe operating voltage window of the battery to avoid overcharging or over-discharging. In some embodiments of the present application, the frequency of the AC current is selected based on factors such as the impedance spectrum characteristics of the battery system, and can be a single specific frequency or a combination of multiple frequencies.

[0032] In some embodiments of the present application, the frequency of the alternating current, the rate of the cyclic charging and discharging, and the number of the cyclic charging and discharging are set according to the remaining capacity of the aged battery.

[0033] In some embodiments of the present application, the higher the residual capacity of the aged battery, the lower the frequency of the alternating current (when the battery capacity is high, the low frequency is used to enhance deep ion migration and help form a dense SEI layer, and when the battery capacity is low, the high frequency is used to break up the layered SEI structure); the higher the residual capacity of the aged battery, the higher the rate of cyclic charge and discharge (when the battery capacity is high, the high rate is used to repair local pores in the SEI, and when the battery capacity is low, the low rate is used to prevent uneven secondary film formation); the higher the residual capacity of the aged battery, the fewer the number of cyclic charge and discharge (when the battery capacity is high, fewer cycles are used for SEI recrystallization, and when the battery capacity is low, more cycles are used to peel off the failed film layer by layer and generate new SEI).

[0034] In some embodiments of the present application, when the remaining capacity of the aged battery is 80% to 95% of its factory rated capacity, the frequency of the AC power is 1K to 1 MHz, the cyclic charge and discharge rate is 0.1C to 1C, and the number of cyclic charge and discharge cycles is 3 to 5. For batteries in this aging stage (mild aging), the method of the present application can optimize and stabilize the SEI film to slow the battery aging process, suppress the rapid increase in internal resistance, and maintain the battery's high performance for as long as possible.

[0035] In some embodiments of the present application, when the remaining capacity of the aged battery is 60% to 80% of its factory rated capacity, the frequency of the AC power is 1K to 1 MHz, the cyclic charge and discharge rate is 0.1C to 0.9C, and the number of charge and discharge cycles is 5 to 8. For batteries in this aging stage (moderate aging), the method of the present application can restore some of the lost capacity to a certain extent, significantly reduce the interfacial impedance by repairing and optimizing the SEI film, and improve the battery's dynamic performance.

[0036] In some embodiments of the present application, when the remaining capacity of the aged battery is less than 60% of the factory rated capacity of the aged battery, the frequency of the alternating current is 1K to 1 MHz, the rate of the cyclic charge and discharge is 0.1C to 0.8C, and the number of cyclic charge and discharge is 8 to 10 times. For batteries in this aging stage (severe aging), the DC bias current rate applied by the method of the present application should preferably not exceed the rate that the battery can withstand during conventional charge and discharge in the current severe aging state, and the voltage and temperature response of the battery should be closely monitored during this process, and whether to increase the number of cycles will be determined based on the response. The method of the present application can activate the remaining activity and improve the interface state of severely aged batteries to a certain extent, thereby extending the battery life to a certain extent.

[0037] Below, in order to more clearly illustrate the technical effects of the present application, the present application sets up different embodiments. Specifically, a number of aged batteries are provided, and their current capacities are measured as initial capacities. Then, the technical solution of the present application is used to maintain them. After the maintained batteries are left to stand for a period of time (for example, 1 to 2 hours) until their internal electrochemical state is stable, their post-maintenance capacities are measured again and compared with the initial capacities to quantify the maintenance effects. Among them, the factory rated capacity of the aged batteries in all embodiments is 700mAh, and all embodiments use a DC bias current superimposed on an AC power. Parameters such as the AC frequency (the frequency of the AC power), the charge and discharge rate (the rate of cyclic charge and discharge), and the number of cycles are different in different embodiments. The relevant parameters and test data in the embodiments are recorded in Table 1 below.

[0038]

[0039] Referring to Table 1, SOH refers to the percentage of the remaining capacity of the aged battery relative to its factory rated capacity. It can be seen that when using the technical solutions of the embodiments of this application to maintain aged batteries, for batteries at different aging stages, the higher the SOH (i.e., the higher the remaining capacity), the lower the frequency of the AC power, and the best maintenance effect; the higher the SOH, the higher the cyclic charge and discharge rate, the best maintenance effect; and the higher the SOH, the fewer the cyclic charge and discharge times, the best maintenance effect.

[0040] In summary, the technical solution of the present application can act more accurately and gently on the inside of the battery, and effectively restore the capacity of the aging battery and extend the battery life by targeting factors such as key interfaces (such as SEI films) that affect the long-term performance and life of the battery. The technical solution of the present application flexibly controls parameters such as the number of cycles, AC frequency, and charge and discharge rates, so that the maintenance method can better adapt to the specific needs of batteries in different chemical systems and different aging stages, thereby achieving personalized and refined maintenance. The present application provides an active intervention method that can not only delay aging, but also restore slight performance degradation caused by interface problems such as SEI films, and maintain the battery in a better health state over a longer period of time.

[0041] The present application provides a battery maintenance method. By applying a composite current consisting of biased DC and specific high-frequency AC to an aging battery, the structure and performance of the SEI film can be gently regulated in a microscopic electrochemical perturbation manner, thereby reducing its impedance and inhibiting its undesirable thickening. This can effectively delay battery aging, maintain and partially restore the battery's performance lost due to interface problems, and ultimately achieve the maintenance effect of extending the overall battery service life.

[0042] In summary, after reading the contents of this application, those skilled in the art will understand that the foregoing contents are presented by way of example only and are not intended to be limiting. Although not expressly stated herein, those skilled in the art will understand that this application is intended to encompass various reasonable changes, improvements, and modifications to the embodiments. Such changes, improvements, and modifications are within the spirit and scope of the exemplary embodiments of this application.

[0043] It should be understood that the term "and / or" used in this embodiment includes any or all combinations of one or more of the associated listed items. It should be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or intervening elements may also be present.

[0044] It should also be understood that the terms “comprise,” “comprising,” “include,” or “including,” when used in this application document, indicate the presence of the recited features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0045] It should also be understood that although the terms first, second, third, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. Therefore, without departing from the teachings of the present application, the first element in some embodiments may be referred to as the second element in other embodiments. The same reference numerals or the same reference designators represent the same elements throughout the specification.

[0046] In addition, this specification describes exemplary embodiments by reference to idealized exemplary cross-sectional views and / or plan views and / or perspective views. Therefore, differences from the illustrated shapes due to, for example, manufacturing techniques and / or tolerances are foreseeable. Therefore, the exemplary embodiments should not be interpreted as limited to the shapes of the regions shown herein, but should include deviations in shapes due to, for example, manufacturing. Therefore, the regions shown in the figures are schematic in nature, and their shapes are not intended to illustrate the actual shapes of the regions of the device nor to limit the scope of the exemplary embodiments.

Claims

1. A battery maintenance method, characterized in that: include: Provide aged batteries; The aged battery is subjected to multiple cycles of charging and discharging, wherein at least one of the charging and discharging uses a DC bias current superimposed on an AC current.

2. The maintenance method according to claim 1, wherein: The remaining capacity of the aged battery is 95% or less of its factory rated capacity.

3. The maintenance method according to claim 2, wherein: The frequency of the alternating current is 1K to 1 MHz, the rate of the cyclic charge and discharge is 0.1C to 1C, and the number of the cyclic charge and discharge is 1 to 10 times.

4. The maintenance method according to claim 3, wherein: The frequency of the alternating current, the rate of the cyclic charging and discharging, and the number of the cyclic charging and discharging are set according to the remaining capacity of the aged battery.

5. The maintenance method according to claim 4, wherein: The higher the remaining capacity of the aged battery, the lower the frequency of the alternating current; the higher the remaining capacity of the aged battery, the higher the rate of the cyclic charge and discharge; and the higher the remaining capacity of the aged battery, the fewer the number of cyclic charge and discharge.

6. The maintenance method according to claim 5, wherein: When the remaining capacity of the aged battery is 80% to 95% of the factory rated capacity of the aged battery, the frequency of the alternating current is 1K to 1 MHz, the rate of the cyclic charge and discharge is 0.1C to 1C, and the number of cyclic charge and discharge is 3 to 5 times.

7. The maintenance method according to claim 5, wherein: When the remaining capacity of the aged battery is 60% to 80% of the factory rated capacity of the aged battery, the frequency of the alternating current is 1K to 1 MHz, the rate of the cyclic charge and discharge is 0.1C to 0.9C, and the number of cyclic charge and discharge times is 5 to 8 times.

8. The maintenance method according to claim 5, wherein: When the remaining capacity of the aged battery is less than 60% of the factory rated capacity of the aged battery, the frequency of the AC power is 1K to 1 MHz, the cyclic charge and discharge rate is 0.1C to 0.8C, and the number of cyclic charge and discharge times is 8 to 10 times.

9. The maintenance method according to claim 1, wherein: The charging and discharging both adopt a direct current bias current superimposed on an alternating current.

10. The maintenance method according to claim 1, wherein: The aging battery is charged and discharged for multiple cycles, comprising: charging the aging battery to a charge cut-off voltage and then discharging the battery to 0% SOC; and repeating the above steps.

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