Active lithium excitation method and application of lithium battery with lithium-supplemented electrode

Abstract

The present invention discloses a method for stimulating active lithium in a lithium battery having a lithium-replenished electrode. The method comprises the following steps: first, placing the lithium battery having the lithium-replenished electrode in an incubator for a preset period of time so that the temperature difference between the inside and outside of the lithium battery is zero; second, counting the number of charge and discharge cycles of the lithium battery in real time during use; third, presetting a correspondence between multiple preset different charge and discharge cycle numbers of the lithium battery and multiple standards; and fourth, detecting in real time whether the number of charge and discharge cycles of the lithium battery has reached a preset number of charge and discharge cycles. Each time a preset number of charge and discharge cycles is reached, the lithium battery is subjected to a charge and discharge cycle operation according to the standard corresponding to the preset number of charge and discharge cycles, thereby periodically and dynamically stimulating and releasing the active lithium replenished in the lithium battery electrode. The present invention can effectively stimulate the replenished active lithium in the lithium-ion battery electrode and effectively increase the battery capacity.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium-ion batteries, and in particular to a method for stimulating active lithium in a lithium battery having a lithium-supplemented electrode and its application. Background Art

[0002] At present, lithium-ion batteries have been widely used in digital products, electric vehicles and energy storage fields due to their advantages such as high energy density, good cycle performance and green and pollution-free.

[0003] As quality assurance requirements for energy storage batteries increase, so too do the requirements for cell cycle life. The loss of active lithium during the cycle decay process of lithium-ion batteries is a major factor affecting the cycle life of cells. Currently, replenishing the active lithium in the battery through lithium supplementation is an important improvement measure.

[0004] However, for lithium-ion batteries, the active lithium after replenishment is affected by polarization and has a delayed effect in its functioning, which affects the effective improvement of the cycle life of the battery cell.

[0005] Therefore, there is an urgent need to develop a technology that can effectively stimulate the active lithium supplemented in lithium-ion batteries so that the lithium ions can be controlled throughout the battery life. Summary of the Invention

[0006] The purpose of the present invention is to provide a method and application for activating active lithium of a lithium battery having a lithium-supplemented electrode in order to address the technical defects of the prior art.

[0007] To this end, the present invention provides a method for activating active lithium in a lithium battery having a lithium-supplemented electrode, which comprises the following steps:

[0008] The first step is to place the lithium battery with the lithium-replenished electrode in a temperature chamber and leave it there for a preset period of time so that the temperature difference between the inside and outside of the lithium battery is zero;

[0009] The second step is to count the number of charge and discharge cycles of the lithium battery in real time during its use, for a lithium battery with a zero temperature difference between the inside and outside.

[0010] Among them, one charge and discharge cycle includes one discharge operation and one charge operation;

[0011] The third step is to pre-set the correspondence between multiple preset different charge and discharge cycle times of the lithium battery and multiple standards;

[0012] The fourth step is to detect in real time whether the number of charge and discharge cycles of the lithium battery reaches a preset number of charge and discharge cycles as the charge and discharge cycle operation of the lithium battery proceeds. Whenever the number of charge and discharge cycles of the lithium battery reaches a preset number of charge and discharge cycles, the lithium battery is subjected to a charge and discharge cycle operation according to the standard corresponding to the preset number of charge and discharge cycles, so as to achieve regular dynamic stimulation and release of the active lithium added in the lithium battery electrode.

[0013] Preferably, the lithium-supplemented electrode sheet is specifically a lithium-supplemented positive electrode sheet or a lithium-supplemented negative electrode sheet.

[0014] Preferably, the lithium-supplemented positive electrode sheet comprises a positive electrode sheet and a lithium sheet connected to each other, wherein the lithium sheet is pressed onto the surface of the positive electrode sheet;

[0015] The lithium-supplemented negative electrode sheet comprises a connected negative electrode sheet and a lithium sheet, wherein the lithium sheet is pressed onto the surface of the negative electrode sheet.

[0016] Preferably, in the first step, the lithium battery with the lithium-replenished electrode is a lithium battery that has just completed the cell shelling operation and the electrolyte injection operation, has not yet undergone charge and discharge cycle operation, and has successively undergone a preset voltage charging formation operation and a high-temperature aging operation.

[0017] Preferably, in the third step, the system, i.e., the charging and discharging rules of the battery, is as follows: under a preset ambient temperature T, the lithium battery is discharged at a constant current of a preset discharge current I2 to a preset discharge lower limit voltage Vr, and then charged at a constant current of a preset charge current I1 to a preset charge upper limit voltage Ve;

[0018] Among them, the charging current is greater than or equal to the discharging current.

[0019] Preferably, in the third step, for the multiple modes corresponding to the multiple preset different numbers of charge and discharge cycles, the preset ambient temperatures T in the multiple modes are equal, or the preset ambient temperature T gradually increases as the number of charge and discharge cycles increases;

[0020] In the third step, for the multiple standards corresponding to the multiple preset different charge and discharge cycle numbers, the preset upper limit charging voltage Ve in the multiple standards is equal, that is, remains unchanged;

[0021] In the third step, for multiple standards corresponding to multiple preset different charge and discharge cycle numbers, the preset lower discharge limit voltages Vr in the multiple standards are equal, or the preset lower discharge limit voltage Vr gradually decreases as the charge and discharge cycle number increases;

[0022] In the third step, for the multiple standards corresponding to the multiple preset different charge and discharge cycle numbers, the charging current I1 in the multiple standards is equal, or the charging current I1 gradually decreases as the charge and discharge cycle number increases;

[0023] In the third step, for a plurality of standards corresponding to a plurality of preset different charge and discharge cycle numbers, the discharge currents I2 in the plurality of standards are equal, or the discharge current I2 gradually decreases as the charge and discharge cycle number increases.

[0024] Preferably, for multiple standards corresponding to multiple preset different numbers of charge and discharge cycles, when the battery life decay rate accelerates during the cycle process, in the subsequent multiple standards, the reduction range of the preset lower discharge limit voltage of the battery gradually increases, the increase range of the preset ambient temperature T gradually increases, and the discharge current is gradually reduced.

[0025] Preferably, when the number of charge and discharge cycles of the lithium battery reaches a preset first number of cycles, a charge and discharge cycle operation is performed according to a preset first standard;

[0026] The preset first cycle number is preferably 1, i.e. the first cycle;

[0027] The first mode is preset, specifically: under a preset first ambient temperature, the lithium battery is discharged at a preset first discharge current constant current to a preset first discharge lower limit voltage, and then is charged at a preset first charge current constant current to a preset first charge upper limit voltage;

[0028] The first ambient temperature is preset to be greater than or equal to the preset ambient temperature in other formats;

[0029] The first charging current of the preset magnitude is greater than or equal to the charging current in other standards;

[0030] A first discharge current of a preset magnitude is greater than or equal to a discharge current in other formats;

[0031] A first upper charging limit voltage is preset, which is equal to a preset upper charging limit voltage in other standards;

[0032] The first lower discharge limit voltage is preset to be equal to or equal to the preset lower discharge limit voltage in other systems.

[0033] The present invention also provides an application of the active lithium excitation method of a lithium battery having a lithium-supplemented electrode as described above, which is applied to a lithium battery having a lithium-supplemented electrode.

[0034] It can be seen from the technical solution provided by the present invention above that, compared with the prior art, the present invention provides a method and application for stimulating active lithium of a lithium battery with a lithium-supplemented electrode. The method is scientifically designed and can effectively stimulate the active lithium supplemented on the electrode of the lithium-ion battery, ensuring the regular supplementation of the active lithium to the battery circulation system, so as to ensure that the active lithium can be controlled during the battery cycle. While making up for the active lithium consumed by the side reactions of the battery, it will not increase the overflow of excess active lithium, and ultimately make the lithium ions controllably function throughout the battery life, effectively improve the capacity of the battery, and greatly extend the service life of the lithium battery, which has important practical significance.

[0035] The present invention is applicable to the lithium replenishment system of lithium-ion batteries. After replenishment, the lithium ions are stored in the electrode (negative electrode or positive electrode). As the cycle progresses, the stored active lithium is stimulated once every preset fixed time, so that the active lithium is replenished into the circulation system to replenish the active lithium loss caused by the destruction and reconstruction of the SEI film (solid electrolyte interface film). The present invention optimizes the relationship between the number of cycles and capacity attenuation, current size, temperature, etc., to achieve quantitative release of active lithium, ensure real-time replenishment of active lithium, and greatly extend the service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The present invention provides a flow chart of a method for stimulating active lithium in a lithium battery having a lithium-supplemented electrode. DETAILED DESCRIPTION

[0037] In order to enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and implementation methods.

[0038] See also Figure 1 The present invention provides a method for activating active lithium in a lithium battery having a lithium-supplemented electrode, comprising the following steps:

[0039] The first step is to place the lithium battery with the lithium-replenished electrode in a temperature chamber and leave it there for a preset period of time so that the temperature difference between the inside and outside of the lithium battery is zero;

[0040] The second step is to count the number of charge and discharge cycles of the lithium battery in real time during the use of the lithium battery, for which the temperature difference between the internal and external temperature is zero (for example, the number can be counted by the battery management system BMS equipped with the lithium battery);

[0041] Among them, one charge-discharge cycle includes one discharge operation and one charge operation. By default, one discharge operation is performed first, and then one charge operation is performed. That is, after each discharge operation and one charge operation, it is counted as one charge-discharge cycle.

[0042] The third step is to pre-set the correspondence between multiple preset different charge and discharge cycle times of the lithium battery and multiple standards;

[0043] The fourth step is to detect in real time whether the number of charge and discharge cycles of the lithium battery reaches a preset number of charge and discharge cycles as the charge and discharge cycle operation of the lithium battery is carried out (during daily use). Whenever the number of charge and discharge cycles of the lithium battery reaches a preset number of charge and discharge cycles, the lithium battery is subjected to a charge and discharge cycle operation according to the standard corresponding to the preset number of charge and discharge cycles, so as to achieve regular dynamic stimulation and release of the active lithium supplemented in the lithium battery electrode, so that the released active lithium is added to the battery circulation system.

[0044] In the present invention, in the first step, the lithium-supplemented electrode sheet, specifically the lithium-supplemented positive electrode sheet or the lithium-supplemented negative electrode sheet;

[0045] For a lithium-ion battery, the lithium-replenished positive electrode sheet and the lithium-replenished negative electrode sheet cannot exist at the same time, and only one of them can be selected.

[0046] A lithium-supplemented positive electrode sheet, comprising a positive electrode sheet and a lithium sheet connected to each other, wherein the lithium sheet is pressed (e.g., connected by rolling) onto the surface of the positive electrode sheet; the positive electrode sheet comprises a positive electrode foil and a positive electrode active material coating applied on the surface of the positive electrode foil, wherein the lithium sheet is pressed onto the positive electrode active material coating;

[0047] The lithium-supplemented negative electrode sheet includes a connected negative electrode sheet and a lithium sheet, and the lithium sheet is pressed (for example, connected by rolling) on ​​the surface of the negative electrode sheet; the negative electrode sheet includes a positive electrode foil and a negative electrode active material coating coated on the surface of the negative electrode foil, and the lithium sheet is pressed on the negative electrode active material coating.

[0048] In the first step, the lithium battery with the lithium-replenished electrode is preferably a lithium battery that has just completed the battery cell shelling operation and the electrolyte injection operation, and has not yet undergone a charge and discharge cycle operation.

[0049] In the first step, a lithium battery with a lithium-filled electrode sheet, preferably one that has just completed the cell shell placement and electrolyte injection process and has not yet undergone charge and discharge cycles, undergoes a charge formation process at a preset voltage and a high-temperature aging process. The high-temperature aging process can be performed at a temperature range of 40 to 45 degrees Celsius.

[0050] In the third step, the system is the battery charge and discharge rule, specifically: under the preset ambient temperature T, the lithium battery is discharged at a preset discharge current I2 to a preset discharge lower limit voltage Vr (i.e., the lower limit cut-off voltage), and then charged at a preset charge current I1 to a preset charge upper limit voltage Ve (i.e., the upper limit cut-off voltage);

[0051] Among them, the charging current is greater than or equal to the discharging current.

[0052] In the third step, in a specific implementation, for multiple standards corresponding to multiple preset different charge and discharge cycle numbers, the preset ambient temperature T in the multiple standards is equal, or the preset ambient temperature T gradually increases as the charge and discharge cycle number increases;

[0053] In the third step, in a specific implementation, for multiple standards corresponding to multiple preset different numbers of charge and discharge cycles, the preset charging upper limit voltage Ve (i.e., upper limit cut-off voltage) in the multiple standards is equal, that is, remains unchanged;

[0054] In the third step, in a specific implementation, for multiple standards corresponding to multiple preset different numbers of charge and discharge cycles, the preset lower discharge voltage Vr (i.e., lower cut-off voltage) in the multiple standards is equal, or as the number of charge and discharge cycles increases, the preset lower discharge voltage Vr (i.e., lower cut-off voltage) gradually decreases;

[0055] In the third step, in a specific implementation, for multiple standards corresponding to multiple preset different charge and discharge cycle numbers, the charging current I1 in the multiple standards is equal, or the charging current I1 gradually decreases as the charge and discharge cycle number increases;

[0056] In the third step, in a specific implementation, for multiple standards corresponding to multiple preset different charge and discharge cycle numbers, the discharge current I2 in the multiple standards is equal, or the discharge current I2 gradually decreases as the charge and discharge cycle number increases.

[0057] It should be noted that, in the present invention, for a plurality of preset different charge and discharge cycle numbers, the interval number between any two adjacent charge and discharge cycle numbers (for example, the interval number between the 300th cycle and the 100th cycle number is 200) is determined accordingly based on the battery's life decay rate during the cycling process. When the battery's life decay rate increases (i.e., accelerates), the interval number decreases (i.e., the frequency X of the cycle number changes increases).

[0058] For example, when the plurality of preset different charge and discharge cycle numbers are: 1st, 100th, 201st, 300th, 400th, 600th, and 1000th, the 100th and 201st are two adjacent charge and discharge cycle numbers.

[0059] In a specific implementation, the intervals between any two adjacent charge and discharge cycles may be different.

[0060] It should be noted that, for the present invention, in the third step, for multiple standards corresponding to multiple preset different numbers of charge and discharge cycles, the preset charging upper limit voltage Ve, the preset discharge lower limit voltage Vr and the discharge current I2 in the multiple standards are synchronized (that is, these variables are changed together according to the set standard values, not a single change), and are determined accordingly according to the life decay rate of the battery during the cycle process.

[0061] According to the present invention, for multiple standards corresponding to multiple preset different numbers of charge and discharge cycles, when the battery life decay rate accelerates during the cycle, in the subsequent multiple standards, the reduction range of the preset lower discharge limit voltage of the battery gradually increases, the increase range of the preset ambient temperature T gradually increases, and the discharge current is gradually reduced, which can stimulate the active lithium stored in the battery cell to a certain extent.

[0062] It should be noted that the battery life decay rate during the cycle process is mainly the trend of capacity reduction during actual battery charging and discharging, which can be obtained through testing using existing charging and discharging instruments (such as the existing Arbin BT2000 charging and discharging test system).

[0063] For the present invention, in the third step, for multiple standards corresponding to multiple preset different charge and discharge cycle numbers, when the battery life decay rate increases (i.e., accelerates) during the cycle, the reduction amplitude of the discharge current I2 (i.e., the reduction amplitude of the discharge current I2 in the two standards corresponding to the two adjacent charge and discharge cycle numbers) increases.

[0064] It should be noted that the greater the reduction in discharge current, the slower release of lithium in the negative electrode will be stimulated during the discharge process, and the greater the amount, which reduces the impact of polarization.

[0065] In the present invention, the increase in the preset ambient temperature T in multiple standards is determined by the battery's lifespan decay rate during cycling. As the battery's lifespan decay rate increases (i.e., accelerates) during cycling, the increase in the preset ambient temperature T (i.e., the decrease in the preset ambient temperature T in the two standards corresponding to two consecutive charge-discharge cycles) increases.

[0066] It should be noted that as the preset ambient temperature T increases, the lithium in the negative electrode plate will be stimulated to be released slowly during the discharge process, and the amount will also be greater, which reduces the impact of polarization.

[0067] In the present invention, in the third step, the ambient temperature, voltage (specifically the lower limit voltage here, while the upper limit voltage remains unchanged), and charge and discharge current in multiple standards can be changed in different standards.

[0068] In the fourth step, in a specific implementation, when the number of charge and discharge cycles of the lithium battery reaches a preset first number of cycles, a charge and discharge cycle operation is performed according to a preset first standard;

[0069] The preset first cycle number is preferably 1, i.e. the first cycle;

[0070] The first mode is preset, specifically: under a preset first ambient temperature, the lithium battery is discharged at a preset first discharge current constant current to a preset first discharge lower limit voltage, and then is charged at a preset first charge current constant current to a preset first charge upper limit voltage;

[0071] The first ambient temperature is preset to be greater than or equal to the preset ambient temperature in other formats;

[0072] The first charging current of the preset magnitude is greater than or equal to the charging current in other standards;

[0073] A first discharge current of a preset magnitude is greater than or equal to a discharge current in other formats;

[0074] A first upper charging limit voltage is preset, which is equal to a preset upper charging limit voltage in other standards;

[0075] The first lower discharge limit voltage is preset to be equal to or equal to the preset lower discharge limit voltage in other systems.

[0076] In the present invention, in specific implementation, the present invention provides an active lithium excitation method for a lithium battery with a lithium-replenished electrode, which is applied to a lithium-ion battery lithium replenishment system, specifically to a lithium battery with a lithium-replenished electrode.

[0077] In order to more clearly understand the technical solution of the present invention, the technical solution of the present invention is described below through specific embodiments.

[0078] Example 1.

[0079] Using a negative electrode sheet for lithium replenishment, a designed lithium-replenishing negative electrode sheet and a normal positive electrode (unreplenished) were assembled into a prismatic soft-pack battery. The resulting battery was charged at 2.5-3.65V (the formation voltage) to achieve formation venting. After seven days of high-temperature aging, the prepared cell was cycled. The default for the following formats is discharge first, then charge.

[0080] At the beginning of the cycle, three cells with the same design were placed in a 25°C incubator for 5 hours, with the temperature difference between the inside and outside of the cells being zero. Charging and discharging were performed using standard 1, with specific standard requirements: the charge and discharge voltage range was 2.5-3.65V, the charge rate was 1C, and the discharge rate was 1C.

[0081] When the number of cycles reaches 100, the battery is charged and discharged at 25°C using standard 2. The specific standard requirements are: lower limit voltage 2.5V, upper limit voltage 3.65V, charge rate 1C, and discharge rate 0.8C.

[0082] When the number of cycles reaches 101, the battery is charged and discharged at 25°C using standard 3. The specific standard requirements are: lower limit voltage 2.5V, upper limit voltage 3.65V, charge rate 1C, and discharge rate 1C.

[0083] When the number of cycles reaches 300, the battery is charged and discharged at 25°C using standard 4. The specific standard requirements are: lower limit voltage 2.5V, upper limit voltage 3.65V, charge rate 1C, and discharge rate 0.6C.

[0084] When the number of cycles reached 301, the battery was charged and discharged at 25°C using standard 5, with the following requirements: lower voltage limit of 2.5V, upper voltage limit of 3.65V, charge rate of 1C, and discharge rate of 1C.

[0085] When the number of cycles reaches 1000, the system is used in format 6, with the following specific requirements: lower limit voltage is 2.5V, upper limit voltage is 3.65V, temperature is 25°C, charging rate is 1C, standing time is 2h, and discharge rate is 0.4C;

[0086] When the number of cycles reaches 1001, charge and discharge are performed at 25°C using standard 7. The specific standard requirements are: lower limit voltage 2.5V, upper limit voltage 3.65V, charge rate 1C, and discharge rate 1C;

[0087] When the number of cycles reaches 5000, the lower limit voltage is 2.5V according to standard 8. The specific standard requirements are: upper limit voltage is 3.65V, temperature is 25℃. The charge rate is 1C and the discharge rate is 0.3C.

[0088] When the number of cycles reaches 5001, the battery is charged and discharged at 25°C using standard 9. The specific standard requirements are: lower limit voltage 2.5V, upper limit voltage 3.65V, charge rate 1C, and discharge rate 1C.

[0089] Example 2.

[0090] Using a negative electrode sheet for lithium replenishment, the designed negative electrode sheet and the positive electrode were assembled into a prismatic soft-pack battery. The resulting battery was charged at 2.5-3.65V (the formation voltage) to achieve formation venting. After seven days of high-temperature aging, the prepared cell was subjected to cycle testing. The default for the following formats is discharge first, then charge.

[0091] At the beginning of the cycle, three cells with the same design were placed in a 25°C incubator for 5 hours, with the temperature difference between the inside and outside of the cells being zero. Charging and discharging were performed using standard 1, with specific standard requirements: the charge and discharge voltage range was 2.5-3.65V, the charge rate was 1C, and the discharge rate was 1C.

[0092] When the number of cycles reaches 100, the battery is charged and discharged at 25°C using standard 2. The specific standard requirements are: lower limit voltage 2.5V, upper limit voltage 3.65V, charge rate 1C, and discharge rate 0.4C.

[0093] When the number of cycles reaches 101, the battery is charged and discharged at 25°C using standard 3. The specific standard requirements are: lower limit voltage 2.5V, upper limit voltage 3.65V, charge rate 1C, and discharge rate 1C.

[0094] When the number of cycles reaches 300, the battery is charged and discharged at 25°C using standard 4. The specific standard requirements are: lower limit voltage 2.5V, upper limit voltage 3.65V, charge rate 1C, and discharge rate 0.3C.

[0095] When the number of cycles reached 301, the battery was charged and discharged at 25°C using standard 5, with the following requirements: lower voltage limit of 2.5V, upper voltage limit of 3.65V, charge rate of 1C, and discharge rate of 1C.

[0096] When the number of cycles reaches 1000, the system is used in format 6, with the following specific requirements: lower voltage limit of 2.5V, upper voltage limit of 3.65V, temperature of 25°C, charge rate of 1C, charge and discharge rest time of 2h, discharge temperature of 28°C, and discharge rate of 0.3C;

[0097] When the number of cycles reaches 1001, charge and discharge are performed at 25°C using standard 7. The specific standard requirements are: lower limit voltage 2.5V, upper limit voltage 3.65V, charge rate 1C, and discharge rate 1C;

[0098] When the number of cycles reaches 5000, the standard 8 is used, and the specific standard requirements are: the lower limit voltage is 2.5V, the upper limit voltage is 3.65V, and the temperature is 25℃. The charge rate is 1C. The charge and discharge rest time is 2h, the discharge temperature is 28℃, and the discharge rate is 0.2C.

[0099] When the number of cycles reaches 5001, the battery is charged and discharged at 25°C using standard 9. The specific standard requirements are: lower limit voltage 2.5V, upper limit voltage 3.65V, charge rate 1C, and discharge rate 1C.

[0100] Example 3.

[0101] Using a negative electrode sheet for lithium replenishment, the designed negative electrode sheet and the positive electrode were assembled into a prismatic soft-pack battery. The resulting battery was charged at 2.5-3.65V (the formation voltage) to achieve formation venting. After seven days of high-temperature aging, the prepared cell was subjected to cycle testing. The default for the following formats is discharge first, then charge.

[0102] At the beginning of the cycle, three cells with the same design were placed in a 25°C incubator for 5 hours, with the temperature difference between the inside and outside of the cells being zero. Charging and discharging were performed using standard 1, with specific standard requirements: the charge and discharge voltage range was 2.5-3.65V, the charge rate was 1C, and the discharge rate was 1C.

[0103] When the number of cycles reaches 100, the battery is charged and discharged at 25°C using standard 2. The specific standard requirements are: lower limit voltage 2.5V, upper limit voltage 3.65V, charge rate 1C, and discharge rate 0.4C.

[0104] When the number of cycles reaches 101, the battery is charged and discharged at 25°C using standard 3. The specific standard requirements are: lower limit voltage 2.5V, upper limit voltage 3.65V, charge rate 1C, and discharge rate 1C.

[0105] When the number of cycles reaches 300, the battery is charged and discharged at 25°C using standard 4. The specific standard requirements are: lower limit voltage 2.5V, upper limit voltage 3.65V, charge rate 1C, and discharge rate 0.3C.

[0106] When the number of cycles reached 301, the battery was charged and discharged at 25°C using standard 5, with the following requirements: lower voltage limit of 2.5V, upper voltage limit of 3.65V, charge rate of 1C, and discharge rate of 1C.

[0107] When the number of cycles reaches 1000, the system is used in format 6, with the following specific requirements: lower voltage limit of 2.5V, upper voltage limit of 3.65V, temperature of 25°C, charge rate of 1C, charge and discharge rest time of 2h, discharge temperature of 28°C, and discharge rate of 0.3C;

[0108] When the number of cycles reaches 1001, charge and discharge are performed at 25°C using standard 7. The specific standard requirements are: lower limit voltage 2.5V, upper limit voltage 3.65V, charge rate 1C, and discharge rate 1C;

[0109] When the number of cycles reaches 5000, the lower limit voltage is 2.4V according to standard 8. The specific standard requirements are: upper limit voltage is 3.65V, temperature is 25℃, charging rate is 1C, charging and discharging rest time is 2h, discharge temperature is 30℃, and discharge rate is 0.2C.

[0110] When the number of cycles reaches 5001, the battery is charged and discharged at 25°C using standard 9. The specific standard requirements are: lower limit voltage 2.5V, upper limit voltage 3.65V, charge rate 1C, and discharge rate 1C.

[0111] Example 4.

[0112] Using a negative electrode for lithium replenishment, the designed negative electrode and positive electrode were assembled into a prismatic soft-pack battery. The resulting battery was charged at 2.5-3.65V (the formation voltage) to achieve formation venting. After seven days of high-temperature aging, the prepared cell was cycled. The default for the following formats is discharge first, then charge.

[0113] At the beginning of the cycle, three cells with the same design were placed in a 25°C incubator for 5 hours, with the temperature difference between the inside and outside of the cells being zero. Charging and discharging were performed using standard 1, with specific standard requirements: the charge and discharge voltage range was 2.5-3.65V, the charge rate was 1C, and the discharge rate was 1C.

[0114] When the number of cycles reaches 100, the battery is charged and discharged at 25°C using standard 2. The specific standard requirements are: lower limit voltage 2.5V, upper limit voltage 3.65V, charge rate 1C, and discharge rate 0.3C.

[0115] When the number of cycles reaches 101, the battery is charged and discharged at 25°C using standard 3. The specific standard requirements are: lower limit voltage 2.5V, upper limit voltage 3.65V, charge rate 1C, and discharge rate 1C.

[0116] When the number of cycles reaches 300, the battery is charged and discharged at 25°C using standard 4. The specific standard requirements are: lower limit voltage 2.5V, upper limit voltage 3.65V, charge rate 1C, and discharge rate 0.2C.

[0117] When the number of cycles reached 301, the battery was charged and discharged at 25°C using standard 5, with the following requirements: lower voltage limit of 2.5V, upper voltage limit of 3.65V, charge rate of 1C, and discharge rate of 1C.

[0118] When the number of cycles reaches 1000, the system is used as standard 6, with the following specific requirements: lower limit voltage is 2.5V, upper limit voltage is 3.65V, charging temperature is 25℃, and charging rate is 1C. The charging and discharging rest time is 2h, the discharge temperature is 28℃, and the discharge rate is 0.3C.

[0119] When the number of cycles reaches 1001, the battery is charged and discharged at 25°C using standard 7, with the following specific requirements: lower voltage limit of 2.0V, upper voltage limit of 3.65V, charge rate of 1C, and discharge rate of 1C.

[0120] When the number of cycles reaches 5000, the standard 8 is used, and the specific standard requirements are: the lower limit voltage is 2.3V, the upper limit voltage is 3.65V, the charging temperature is 25℃, and the charging rate is 1C. The charge and discharge rest time is 2h, the discharge temperature is 33℃, and the discharge rate is 0.1C;

[0121] When the number of cycles reaches 5001, the battery is charged and discharged at 25°C using standard 9. The specific standard requirements are: lower limit voltage 2.0V, upper limit voltage 3.65V, charge rate 1C, and discharge rate 1C.

[0122] Example 5.

[0123] Using a negative electrode for lithium replenishment, the designed negative electrode and positive electrode were assembled into a prismatic soft-pack battery. The resulting battery was charged at 2.5-3.65V (the formation voltage) to achieve formation venting. After seven days of high-temperature aging, the prepared cell was cycled. The default for the following formats is discharge first, then charge.

[0124] At the beginning of the cycle, three cells with the same design were placed in a 25°C incubator for 5 hours, with the temperature difference between the inside and outside of the cells being zero. Charging and discharging were performed using standard 1, with specific standard requirements: the charge and discharge voltage range was 2.5-3.65V, the charge rate was 1C, and the discharge rate was 1C.

[0125] When the number of cycles reaches 100, the battery is charged and discharged at 25°C using standard 2. The specific standard requirements are: lower limit voltage 2.5V, upper limit voltage 3.65V, charge rate 1C, and discharge rate 0.4C.

[0126] When the number of cycles reaches 101, the battery is charged and discharged at 25°C using standard 3. The specific standard requirements are: lower limit voltage 2.5V, upper limit voltage 3.65V, charge rate 1C, and discharge rate 1C.

[0127] When the number of cycles reaches 300, the battery is charged and discharged at 25°C using standard 4. The specific standard requirements are: lower limit voltage 2.5V, upper limit voltage 3.65V, charge rate 1C, and discharge rate 0.2C.

[0128] When the number of cycles reached 301, the battery was charged and discharged at 25°C using standard 5, with the following requirements: lower voltage limit of 2.5V, upper voltage limit of 3.65V, charge rate of 1C, and discharge rate of 1C.

[0129] When the number of cycles reaches 1000, the system is used as standard 6, with the following specific requirements: the lower limit voltage range is 2.0V, the upper limit voltage is 3.65V, the charging temperature is 25℃, and the charging rate is 1C. The charge and discharge rest time is 2h, the discharge temperature is 28℃, and the discharge rate is 0.1C.

[0130] When the number of cycles reaches 1001, charge and discharge are performed at 25°C using standard 7. The specific standard requirements are: lower limit voltage 2.5V, upper limit voltage 3.65V, charge rate 1C, and discharge rate 1C;

[0131] When the number of cycles reaches 5000, the lower limit voltage is 2.0V according to standard 8. The specific standard requirements are: upper limit voltage is 3.65V, charging temperature is 25℃, and charging rate is 1C. The charge and discharge rest time is 2h, the discharge temperature is 40℃, and the discharge rate is 0.05C.

[0132] When the number of cycles reaches 5001, the battery is charged and discharged at 25°C using standard 9. The specific standard requirements are: lower limit voltage 2.0V, upper limit voltage 3.65V, charge rate 1C, and discharge rate 1C.

[0133] Example 6.

[0134] Using a positive electrode lithium replenishment method, the designed lithium-replenishing positive electrode sheet and negative electrode were assembled into a prismatic soft-pack battery. The battery was charged at 2.5-3.65V (i.e., the formation voltage) to achieve formation venting. After 7 days of high-temperature aging, the prepared battery cell was subjected to cycle testing. The default setting for the following formats is: discharge first, then charge.

[0135] At the beginning of the cycle, three cells of the same design were placed in a 25°C incubator for 5 hours, with the temperature difference between the inside and outside of the cells being zero. Charging and discharging were performed using standard 1, with specific standard requirements: a charge and discharge voltage range of 2.5-3.65V, a charge rate of 1C, and a discharge rate of 1C.

[0136] When the number of cycles reaches 100, charge and discharge at 25°C are performed using system 2. The specific system requirements are: lower limit voltage 2.5V, upper limit voltage 3.65V, charge rate 1C, and discharge rate 0.4C;

[0137] When the number of cycles reaches 101, the battery is charged and discharged at 25°C using standard 3. The specific standard requirements are: lower limit voltage 2.5V, upper limit voltage 3.65V, charge rate 1C, and discharge rate 1C.

[0138] When the number of cycles reaches 300, the battery is charged and discharged at 25°C using standard 4. The specific standard requirements are: lower limit voltage 2.5V, upper limit voltage 3.65V, charge rate 1C, and discharge rate 0.3C.

[0139] When the number of cycles reached 301, the battery was charged and discharged at 25°C using standard 5, with the following requirements: lower voltage limit of 2.5V, upper voltage limit of 3.65V, charge rate of 1C, and discharge rate of 1C.

[0140] When the number of cycles reaches 3000, the system is used as standard 6, with the following specific requirements: lower limit voltage is 2.5V, upper limit voltage is 3.65V, charging temperature is 25℃, charging rate is 1C. The charging and discharging rest time is 2h, the discharge temperature is 28℃, and the discharge rate is 0.3C.

[0141] When the number of cycles reaches 3001, the battery is charged and discharged at 25°C using standard 7. The specific standard requirements are: lower limit voltage 2.5V, upper limit voltage 3.65V, charge rate 1C, and discharge rate 1C.

[0142] When the number of cycles reaches 8000, the lower limit voltage is 2.0V according to standard 8. The specific standard requirements are: upper limit voltage is 3.65V, charging temperature is 25℃, and charging rate is 1C. The charge and discharge rest time is 2h, the discharge temperature is 40℃, and the discharge rate is 0.2C.

[0143] When the number of cycles reaches 8001, the battery is charged and discharged at 25°C using system 9. The specific system requirements are: lower limit voltage 2.0V, upper limit voltage 3.65V, charge rate 1C, and discharge rate 1C.

[0144] The above Examples 1 to 6, compared with the existing traditional 1C / 1C (i.e., charging rate 1C / discharging rate 1C) battery charge and discharge cycle, have improved effects as shown in Table 1 below. As can be seen from Table 1, the technical solution of the present invention can effectively stimulate the active lithium supplemented in the lithium-ion battery, ensure the real-time supplementation of the active lithium, and ensure that the battery capacity is reliably improved.

[0145] Table 1:

[0146] Example Capacity maintains the increase ratio Example 1 ≥0.5％ Example 2 ≥0.9％ Example 3 ≥1.1％ Example 4 ≥1.5％ Example 5 ≥1.8％ Example 6 ≥0.7％

[0147] In summary, compared with the prior art, the present invention provides a method and application for stimulating active lithium of a lithium battery with a lithium-replenished electrode. The method is scientifically designed and can effectively stimulate the active lithium replenished on the electrode of the lithium-ion battery, ensuring the regular replenishment of the active lithium to the battery circulation system, so as to ensure that the active lithium can be controlled during the battery cycle. While making up for the active lithium consumed by the side reactions of the battery, it will not increase the overflow of excess active lithium, and ultimately make the lithium ions controllably function throughout the battery life, effectively improve the capacity of the battery, and greatly extend the service life of the lithium battery, which has important practical significance.

[0148] The present invention is applicable to the lithium replenishment system of lithium-ion batteries. After replenishment, the lithium ions are stored in the electrode (negative electrode or positive electrode). As the cycle progresses, the stored active lithium is stimulated once every preset fixed time, so that the active lithium is replenished into the circulation system to replenish the active lithium loss caused by the destruction and reconstruction of the SEI film (solid electrolyte interface film). The present invention optimizes the relationship between the number of cycles and capacity attenuation, current size, temperature, etc., to achieve quantitative release of active lithium, ensure real-time replenishment of active lithium, and greatly extend the service life.

[0149] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for activating active lithium in a lithium battery having a lithium-supplemented electrode, characterized in that: The following steps are involved: The first step is to place the lithium battery with the lithium-replenished electrode in a temperature chamber and leave it there for a preset period of time so that the temperature difference between the inside and outside of the lithium battery is zero; The second step is to count the number of charge and discharge cycles of the lithium battery in real time during its use, for a lithium battery with a zero temperature difference between the inside and outside. Among them, one charge and discharge cycle includes one discharge operation and one charge operation; The third step is to pre-set the correspondence between multiple preset different charge and discharge cycle times of the lithium battery and multiple standards; the standard is the charge and discharge rule of the battery, specifically: under the preset ambient temperature T, the lithium battery is discharged with a preset discharge current I2 to a preset discharge lower limit voltage Vr, and then charged with a preset charge current I1 to a preset charge upper limit voltage Ve; Among them, the charging current is greater than or equal to the discharging current; For multiple modes corresponding to different preset numbers of charge and discharge cycles, the preset ambient temperatures T in the multiple modes are equal, or the preset ambient temperature T gradually increases as the number of charge and discharge cycles increases; For multiple standards corresponding to multiple preset different numbers of charge and discharge cycles, the preset upper limit charging voltage Ve in the multiple standards is equal, that is, remains unchanged; For multiple standards corresponding to multiple preset different charge and discharge cycle numbers, the preset lower discharge limit voltages Vr in the multiple standards are equal, or the preset lower discharge limit voltage Vr gradually decreases as the charge and discharge cycle number increases; For multiple standards corresponding to multiple preset different charge and discharge cycle numbers, the charging current I1 in the multiple standards is equal, or the charging current I1 gradually decreases as the charge and discharge cycle number increases; For multiple modes corresponding to different preset numbers of charge and discharge cycles, the discharge current I2 in the multiple modes is equal, or the discharge current I2 gradually decreases as the number of charge and discharge cycles increases; The fourth step is to detect in real time whether the number of charge and discharge cycles of the lithium battery reaches a preset number of charge and discharge cycles as the charge and discharge cycle operation of the lithium battery proceeds. Whenever the number of charge and discharge cycles of the lithium battery reaches a preset number of charge and discharge cycles, the lithium battery is subjected to a charge and discharge cycle operation according to the standard corresponding to the preset number of charge and discharge cycles, so as to achieve regular dynamic stimulation and release of the active lithium added in the lithium battery electrode.

2. The method for activating active lithium in a lithium battery having a lithium-supplemented electrode as claimed in claim 1, wherein: Lithium-replenished electrode sheets, specifically lithium-replenished positive electrode sheets or lithium-replenished negative electrode sheets.

3. The method for activating active lithium in a lithium battery having a lithium-supplemented electrode as claimed in claim 2, wherein: A lithium-supplemented positive electrode sheet, comprising a positive electrode sheet and a lithium sheet connected to each other, wherein the lithium sheet is pressed onto the surface of the positive electrode sheet; The lithium-supplemented negative electrode sheet comprises a connected negative electrode sheet and a lithium sheet, wherein the lithium sheet is pressed onto the surface of the negative electrode sheet.

4. The method for activating active lithium in a lithium battery having a lithium-supplemented electrode as claimed in claim 1, wherein: In the first step, the lithium battery with lithium-replenished electrodes is a lithium battery that has just completed the cell shelling operation and electrolyte injection operation, and has not yet undergone charge and discharge cycle operation, and has successively undergone preset voltage charging and formation operation and high-temperature aging operation.

5. The method for activating active lithium in a lithium battery having a lithium-supplemented electrode as claimed in claim 1, wherein: For multiple standards corresponding to multiple preset different numbers of charge and discharge cycles, when the battery life decay rate accelerates during the cycle process, in the subsequent multiple standards, the reduction range of the preset lower discharge limit voltage of the battery gradually increases, the increase range of the preset ambient temperature T gradually increases, and the discharge current gradually decreases.

6. The method for activating active lithium in a lithium battery having a lithium-supplemented electrode as claimed in claim 1, wherein: When the number of charge and discharge cycles of the lithium battery reaches a preset first number of cycles, a charge and discharge cycle operation is performed according to a preset first standard; The first mode is preset, specifically: under a preset first ambient temperature, the lithium battery is discharged at a preset first discharge current constant current to a preset first discharge lower limit voltage, and then is charged at a preset first charge current constant current to a preset first charge upper limit voltage; The first ambient temperature is preset to be greater than or equal to the preset ambient temperature in other formats; The first charging current of the preset magnitude is greater than or equal to the charging current in other standards; A first discharge current of a preset magnitude is greater than or equal to a discharge current in other formats; A first upper charging limit voltage is preset, which is equal to a preset upper charging limit voltage in other standards; The preset first lower discharge limit voltage is equal to the preset lower discharge limit voltage in other systems.

7. The method for activating active lithium in a lithium battery having a lithium-supplemented electrode according to claim 6, characterized in that: The preset first cycle number is 1, ie the first cycle.

8. An application of the active lithium excitation method of a lithium battery having a lithium-supplemented electrode as claimed in any one of claims 1 to 7, characterized in that: Applicable to lithium batteries with lithium-replenished electrodes.

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