A battery lithium supplement method and a battery prepared by using the same

Abstract

The application provides a battery lithium supplement method and a battery prepared by using the same, which comprises the following steps: preparing a semi-finished lithium ion battery and preparing a lithium supplement electrode; placing the lithium supplement electrode in a gas bag filled with protective gas, and then supplementing lithium for the semi-finished lithium ion battery. The method can accurately control the improvement range of coulomb efficiency and avoid excessive lithium supplement. The method can avoid using lithium powder for lithium battery lithium supplement, can improve the process safety compared with mainstream processes, and does not deteriorate the battery performance. The lithium ion battery obtained by using the lithium supplement method is prepared. The lithium supplement electrode can supplement lithium for the positive electrode and the negative electrode respectively. The lithium supplement lithium source is a lithium sheet. The lithium supplement electrode is placed in the gas bag, and the gas bag is reserved during formation. The lithium supplement step is performed after formation, and the lithium supplement amount is calculated by current and time.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery technology, and specifically relates to a lithium replenishment method for batteries and batteries prepared using the same method. Background Technology

[0002] With the technological development of 3C digital products, the volumetric energy density of lithium-ion batteries is also increasing, which has driven the high development of silicon-carbon anodes. Silicon-carbon anodes have a specific capacity much higher than that of graphite materials, but due to the characteristics of the materials, they have the problem of low coulombic efficiency during the first charge and discharge. At present, the industry mainly solves the problem of low coulombic efficiency of lithium-ion batteries through two directions: 1. Lithium supplementation additives for the positive electrode; 2. Lithium supplementation through the anode electrode process.

[0003] Chinese patent application CN109004304A, "Method for Lithium Supplementation of Soft-Pack Lithium-ion Batteries and Preparation Method of Lithium-ion Batteries and Intermediate Lithium Supplementation Battery", places the lithium supplementation electrode in a gas bag containing electrolyte after the cell is packaged. That is, the lithium supplementation electrode is also in the gas bag, but it also contains electrolyte, and it does not directly use lithium sheets for lithium supplementation. Chinese patent application CN109103419A, "A Lithium-ion Battery Negative Electrode for Lithium Supplementation and Preparation Method Thereof", coats the surface of the pre-lithiation electrode with an organic thin film layer, which is composed of electrolyte lithium salt dissolved in an organic solvent.

[0004] The above methods have their own problems, such as high cost, high security risk, performance degradation, and unstable improvement in coulomb efficiency. Summary of the Invention

[0005] The purpose of this invention is to develop a method for replenishing lithium in a battery and a battery prepared using the same method, thereby improving the discharge capacity of lithium batteries, reducing safety risks, and ensuring accurate replenishment of lithium.

[0006] This invention provides a method for replenishing lithium in a battery, comprising: preparing a semi-finished lithium-ion battery and preparing a lithium replenishing electrode; placing the lithium replenishing electrode in a gas bag filled with protective gas, and then replenishing lithium in the semi-finished lithium-ion battery.

[0007] Furthermore, the method for preparing a semi-finished lithium-ion battery includes:

[0008] Step 1: Provide a current collector, and apply an active material onto the current collector using a gap or continuous coating method to prepare the positive electrode precursor and the negative electrode precursor respectively;

[0009] Step 2: Fabricate the positive and negative electrode precursors prepared in Step 1 into a tab-centered or multi-tab structure to obtain the positive and negative electrode sheets.

[0010] Step 3: The prepared positive and negative electrode sheets are wound together with the separator to form a positive bare cell and a negative bare cell, respectively; the separator is made by a wet process.

[0011] Step 4: Encapsulate the positive and negative bare cells using aluminum-plastic film and then bake them;

[0012] Step 5: After baking, inject liquid to obtain a semi-finished lithium-ion battery.

[0013] In step 1 above, the positive electrode precursor is prepared by dissolving LCO / sodium cobaltate, SP, and PVDF in NMP at a mass ratio of 97:2:1 and stirring for 8-10 hours to achieve uniform dispersion, thereby obtaining a mixed slurry. The mixed slurry is then coated onto the surface of the current collector aluminum foil at a coating speed of 4 m / min, dried at 80-120℃, and then rolled at room temperature for 1-48 hours to produce the positive electrode precursor.

[0014] In step 1 above, the negative electrode precursor formulation and sheet preparation involves dissolving graphite, silicon suboxide, SP, dispersant (CMC), and binder (SBR) in deionized water at a ratio of 87.3:10:0.3:1.1:1.3, stirring for 8-10 hours to ensure uniform dispersion, and obtaining a mixed slurry. The mixed slurry is then coated onto the surface of the current collector copper foil at a coating speed of 4 m / min, dried at 100±5℃, and then subjected to room temperature roll pressing for 1-48 hours to produce the negative electrode precursor.

[0015] In step 4 above, the aluminum-plastic film is DNP113um.

[0016] In step 4 above, the baking temperature is 85±1℃ and the baking time is 24-72h.

[0017] Furthermore, the method for preparing the lithium-filling electrode includes:

[0018] Three-electrode tabs are fabricated in a glove box, and the materials used are baked in an inert gas environment; the lithium sheet and the tabs are fixed together by winding a diaphragm to obtain a lithium replenishment electrode; the diaphragm is made by a wet process.

[0019] In the above method for preparing lithium-ion electrodes, the baking temperature is 85±1℃ and the baking time is 24-72h.

[0020] In the above method for preparing lithium-ion electrodes, the inert atmosphere is an argon atmosphere.

[0021] Furthermore, the lithium replenishment process includes:

[0022] (1) Place the lithium replenishment electrode in the relative position of the seal on the semi-finished lithium-ion battery;

[0023] (2) The lithium replenishment electrode is encapsulated in a gas bag filled with protective gas;

[0024] (3) After the battery is left to stand and formed, it is placed in a charging and discharging device for lithium replenishment to complete the replenishment.

[0025] In step (3) above, the battery is resealed after being charged, and then subjected to capacity testing and edge folding processes to complete the manufacturing process.

[0026] In step (3) above, during charging and discharging, the Ni electrode is connected to the positive electrode of the device, and the lithium replenishment electrode is connected to the negative and / or positive electrode of the charging and discharging device. The device adopts the discharge step, the discharge current is 0.1C, and the discharge capacity is designed to be 3 to 6% of the battery design capacity.

[0027] Furthermore, the semi-finished lithium-ion battery is replaced with a semi-finished sodium-ion battery, and the lithium replenishment method is replaced with a sodium replenishment method.

[0028] Secondly, the present invention provides a lithium-ion battery obtained by the above-described lithium replenishment method.

[0029] Furthermore, the lithium replenishment method is replaced with a sodium replenishment method, and the lithium-ion battery is replaced with a sodium-ion battery.

[0030] The method of this invention can precisely control the improvement in coulombic efficiency and avoid excessive lithium replenishment; it can avoid using lithium powder for lithium battery replenishment, and can improve process safety compared with mainstream processes; and it has virtually no degradation to battery performance.

[0031] This invention produces a lithium replenishment electrode that can replenish lithium to both the positive and negative electrodes separately; the lithium source used for replenishment is a lithium sheet; the lithium replenishment electrode is placed inside a gas bag, which is retained during formation; the lithium replenishment step is performed after formation, and the amount of lithium replenishment is calculated by using current and time. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the lithium replenishment electrode structure in Embodiment 1 of the present invention.

[0033] In the diagram, 1 is the lithium sheet, 2 is the separator, and 3 is the aluminum tab.

[0034] Figure 2 This is a schematic diagram of the structure in Embodiment 1 of the present invention, in which the lithium replenishment electrode is placed in a relative position to a seal for encapsulation;

[0035] In the diagram, 4 is the positive electrode tab, 5 is the negative electrode tab, 6 is the main body of the battery cell, 7 is the lithium replenishment electrode, 8 is the top seal, 9 is the first seal, 10 is the side seal, and 11 is the air bag. Detailed Implementation

[0036] To make the inventive objectives, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the embodiments described in this specification are merely for explaining the invention and are not intended to limit the invention. Specific parameter settings in the embodiments can be selected according to local conditions and have no substantial impact on the results.

[0037] In this embodiment of the invention, battery formation refers to activating the positive and negative electrode materials inside the battery cell through charging and discharging, thereby improving the battery's self-discharge, charge-discharge performance, and storage performance; capacity grading refers to classifying the battery capacity after the battery is manufactured by testing the battery capacity and other electrical performance parameters.

[0038] In this embodiment of the invention, LCO is lithium cobalt oxide.

[0039] In this embodiment of the invention, SP is styrene-modified phenol.

[0040] In this embodiment of the invention, PVDF is polyvinylidene fluoride.

[0041] In this embodiment of the invention, NMP is N-methylpyrrolidone.

[0042] In this embodiment of the invention, the dispersant is CMC, carboxymethyl cellulose.

[0043] In this embodiment of the invention, the adhesive is SBR, a styrene-butadiene latex adhesive.

[0044] In this embodiment of the invention, the solution is dissolved in NMP, and the amount of NMP used is based on the complete dissolution of LCO / sodium cobaltate, SP, and PVDF.

[0045] In this embodiment of the invention, the material is dissolved in deionized water, and the amount of deionized water is sufficient to completely dissolve the graphite, silicon suboxide, SP, dispersant, and binder.

[0046] In this embodiment of the invention, LCO, sodium cobaltate, SP, PVDF, graphite, silica, SP, CMC, and SBR are commercially available analytical grade reagents.

[0047] In this embodiment of the invention, the aluminum-plastic film is DNP113um.

[0048] In this embodiment of the invention, the high-temperature baking temperature is 85±1℃ and the time is 24~72h.

[0049] In this embodiment of the invention, the inert atmosphere is an argon atmosphere.

[0050] Example 1

[0051] Cathode precursor formulation and sheet preparation: LCO, SP and PVDF are dissolved in NMP at a mass ratio of 97:2:1 and stirred thoroughly for 10 hours to ensure uniform dispersion. The mixed slurry is then coated onto the surface of aluminum foil at a coating speed of 4 m / min, dried at 80°C, and rolled at room temperature for 5 hours.

[0052] Negative electrode precursor formulation and sheet preparation: Graphite, silicon suboxide, SP, dispersant (CMC), and binder (SBR) are dissolved in deionized water in a ratio of 87.3:10:0.3:1.1:1.3 and stirred for 10 hours to achieve uniform dispersion. The mixed slurry is coated onto the surface of copper foil at a coating speed of 4 m / min and dried at 100±5℃. It is then subjected to room temperature roller pressing for 5 hours.

[0053] Electrode fabrication is performed using a centrally positioned tab.

[0054] The prepared electrode sheets and separators are wound together to form a bare battery cell.

[0055] The film is used for encapsulation and then baked at high temperature. The high temperature baking temperature is 85±1℃ and the time is 24h.

[0056] The three-electrode tabs are fabricated in a glove box. The materials used need to be baked at high temperature (85±1℃) for 24 hours in an inert gas environment. The lithium sheet and the tabs are fixed together by winding a diaphragm to form a lithium replenishment electrode, as shown in the structure. Figure 1 As shown;

[0057] After the battery is filled with electrolyte, the lithium replenishment electrode is placed in a relatively closed seal for encapsulation, as shown in the structure below. Figure 2 As shown;

[0058] After the battery has been left to stand and formed, it is placed on a dedicated lithium replenishment charging and discharging device. At this time, the Ni electrode is connected to the positive electrode of the device, and the lithium replenishment electrode is connected to the negative electrode of the device. The device adopts a discharge step with a discharge current of 0.1C and a discharge capacity designed to be 3% of the battery's design capacity.

[0059] After being recharged, the battery undergoes normal secondary sealing, capacity testing, edge folding, and other processes to complete the manufacturing process.

[0060] Example 2

[0061] Cathode precursor formulation and sheet preparation: LCO, SP and PVDF are dissolved in NMP at a mass ratio of 97:2:1 and stirred thoroughly for 10 hours to ensure uniform dispersion. The mixed slurry is then coated onto the surface of aluminum foil at a coating speed of 4 m / min, dried at 90°C, and then rolled at room temperature for 15 hours.

[0062] Negative electrode precursor formulation and sheet preparation: Graphite, silicon suboxide, SP, dispersant (CMC), and binder (SBR) are dissolved in deionized water in a ratio of 87.3:10:0.3:1.1:1.3 and stirred for 8 hours to achieve uniform dispersion. The mixed slurry is coated onto the surface of copper foil at a coating speed of 4 m / min and dried at 100±5℃. It is then subjected to room temperature roller pressing for 15 hours.

[0063] Electrode fabrication is performed using a centrally positioned tab.

[0064] The prepared electrode sheets and separators are wound together to form a bare battery cell.

[0065] The film is used for encapsulation, followed by high-temperature baking; the high-temperature baking time is 36 hours.

[0066] The three-electrode tabs are fabricated in a glove box. The materials used need to be baked at high temperature in an inert gas environment for 36 hours. The lithium sheet and the tabs are fixed together by winding a diaphragm to form a lithium replenishment electrode. Figure 1 );

[0067] After the battery is filled with electrolyte, the lithium replenishment electrode is placed in a relatively closed seal for encapsulation.

[0068] After the battery has been left to stand and formed, it is placed on a dedicated lithium replenishment charging and discharging device. At this time, the Ni electrode is connected to the positive electrode of the device, and the lithium replenishment electrode is connected to the negative electrode of the device. The device adopts a discharge step with a discharge current of 0.1C and a discharge capacity designed to be 6% of the battery's design capacity.

[0069] After being recharged, the battery undergoes normal secondary sealing, capacity testing, edge folding, and other processes to complete the manufacturing process.

[0070] Example 3

[0071] Positive electrode precursor formulation and sheet preparation: LCO, SP and PVDF are dissolved in NMP at a mass ratio of 97:2:1 and stirred thoroughly for 10 hours to ensure uniform dispersion. The mixed slurry is then coated onto the surface of aluminum foil at a coating speed of 4 m / min and dried at 120°C. It is then subjected to room temperature roller pressing.

[0072] Negative electrode precursor formulation and sheet preparation: Graphite, silicon suboxide, SP, dispersant (CMC), and binder (SBR) are dissolved in deionized water in a ratio of 87.3:10:0.3:1.1:1.3 and stirred for 9 hours to achieve uniform dispersion. The mixed slurry is coated onto the copper foil surface at a coating speed of 4 m / min and dried at 100±5℃, followed by room temperature roll pressing.

[0073] Electrode fabrication is performed using a centrally positioned tab.

[0074] The prepared electrode sheets and separators are wound together to form a bare battery cell.

[0075] The film is used for encapsulation, followed by high-temperature baking; the high-temperature baking time is 48 hours.

[0076] The three-electrode tabs are fabricated in a glove box. The materials used need to be baked at high temperature in an inert gas environment for 48 hours. The lithium sheet and the tabs are fixed together by winding a diaphragm to form a lithium replenishment electrode. Figure 1 ;

[0077] After the battery is filled with electrolyte, the lithium replenishment electrode is placed in a relatively closed seal for encapsulation.

[0078] After the battery has been left to stand and formed, it is placed on a dedicated lithium replenishment charging and discharging device. At this time, the Al tab and the lithium replenishment electrode are connected to the device. The device adopts a discharge step with a discharge current of 0.1C and a discharge capacity designed to be 6% of the battery's design capacity.

[0079] After being recharged, the battery undergoes normal secondary sealing, capacity testing, edge folding, and other processes to complete the manufacturing process.

[0080] Comparative Example 1

[0081] Cathode precursor formulation and sheet preparation: LCO, SP and PVDF are dissolved in NMP at a mass ratio of 97:2:1 and stirred thoroughly for 10 hours to ensure uniform dispersion. The mixed slurry is then coated onto the surface of aluminum foil at a coating speed of 4 m / min and dried at 80-120℃. It is then subjected to room temperature roller pressing.

[0082] Negative electrode precursor formulation and sheet preparation: Negative electrode formulation and sheet preparation: Graphite, silicon suboxide, SP, dispersant (CMC), and binder (SBR) are dissolved in deionized water in a ratio of 87.3:10:0.3:1.1:1.3 and stirred for 10 hours to achieve uniform dispersion. The mixed slurry is coated onto the surface of copper foil at a coating speed of 4 m / min and dried at 100±5℃ and then rolled at room temperature.

[0083] Electrode fabrication is performed using a centrally positioned tab.

[0084] The prepared electrode sheets and separators are wound together to form a bare battery cell.

[0085] The product is sealed using aluminum-plastic film and then baked.

[0086] After the battery is filled with electrolyte, it undergoes aging, encapsulation, formation, secondary sealing, capacity testing, and edge folding processes to complete the manufacturing process.

[0087] That is, steps 5-7 are omitted.

[0088] Table 1. Differences between the Examples and Comparative Examples:

[0089]

[0090]

[0091] As can be seen from Table 1, the new process can significantly improve the first-cycle efficiency of the full cell.

[0092] Compared with patent CN109004304A: This invention uses a lithium sheet as the lithium source, and the lithium replenishment step occurs after battery formation, thus not affecting the film formation effect on the negative electrode during the first charge. Furthermore, the gas bag with the lithium replenishment electrode is removed after the second sealing, allowing it to be retained to collect harmful gases generated during formation and improve the battery's high-temperature performance. This invention has advantages in high-temperature storage. Additionally, this structure adds a lithium replenishment electrode, and lithium replenishment is performed by connecting the positive and negative electrodes and the lithium replenishment electrode during charging and discharging. The amount of lithium replenished can be precisely controlled by adjusting the current and time. Simultaneously, the positive electrode and the lithium replenishment electrode can be connected to replenish lithium to the positive electrode. The results are shown in Table 2.

[0093] Table 2

[0094]

[0095] Calculation of precise lithium replenishment:

[0096] By controlling the current and time of the connection circuit between the lithium replenishment electrode and the positive or negative electrode, the capacity replenished in the lithium replenishment step can be calculated according to the following formula:

[0097] Lithium replenishment capacity Q = Lithium replenishment current I * Lithium replenishment time T;

[0098] The unit for lithium replenishment current is mA, the unit for lithium replenishment time is h, and the unit for lithium replenishment capacity is mAh.

[0099] Compared with patent CN109103419A: This invention introduces a lithium replenishment electrode for lithium replenishment. The amount of lithium replenished can be theoretically calculated using current and time, resulting in higher lithium replenishment accuracy. At the same time, it does not require multiple coatings, making the manufacturing cycle and cost more advantageous.

[0100] Example 4

[0101] Cathode precursor formulation and sheet preparation: LCO, SP and PVDF are dissolved in NMP at a mass ratio of 97:2:1 and stirred thoroughly for 10 hours to ensure uniform dispersion. The mixed slurry is then coated onto the surface of aluminum foil at a coating speed of 4 m / min, dried at 80°C, and then rolled at room temperature for 8 hours.

[0102] Negative electrode precursor formulation and sheet preparation: Graphite, silicon suboxide, SP, dispersant (CMC), and binder (SBR) are dissolved in deionized water in a ratio of 87.3:10:0.3:1.1:1.3 and stirred for 10 hours to achieve uniform dispersion. The mixed slurry is coated onto the surface of copper foil at a coating speed of 4 m / min and dried at 100±5℃. It is then subjected to room temperature roll pressing for 8 hours.

[0103] A multi-electrode structure is used for electrode fabrication;

[0104] The prepared electrode sheets and separators are wound together to form a bare battery cell.

[0105] The film is used for encapsulation and then baked at high temperature. The high temperature baking temperature is 85±1℃ and the time is 72h.

[0106] The three-electrode tabs are fabricated in a glove box. The materials used need to be baked at high temperature in an inert gas environment, at a temperature of 85±1℃ for 72 hours. The lithium sheet and the tabs are fixed together by wrapping a diaphragm to form a lithium replenishment electrode.

[0107] After the battery is filled with electrolyte, the lithium replenishment electrode is placed in a relatively closed seal for encapsulation.

[0108] After the battery has been left to stand and formed, it is placed on a dedicated lithium replenishment charging and discharging device. At this time, the Ni electrode is connected to the positive electrode of the device, and the lithium replenishment electrode is connected to the negative electrode of the device. The device adopts a discharge step with a discharge current of 0.1C and a discharge capacity designed to be 3% of the battery's design capacity.

[0109] After being recharged, the battery undergoes normal secondary sealing, capacity testing, edge folding, and other processes to complete the manufacturing process.

[0110] Example 5

[0111] Cathode precursor formulation and sheet preparation: LCO, SP and PVDF are dissolved in NMP at a mass ratio of 97:2:1 and stirred thoroughly for 10 hours to ensure uniform dispersion. The mixed slurry is then coated onto the surface of aluminum foil at a coating speed of 4 m / min, dried at 80°C, and then rolled at room temperature for 9 hours.

[0112] Negative electrode precursor formulation and sheet preparation: Graphite, silicon suboxide, SP, dispersant (CMC), and binder (SBR) are dissolved in deionized water in a ratio of 87.3:10:0.3:1.1:1.3 and stirred for 10 hours to achieve uniform dispersion. The mixed slurry is coated onto the surface of copper foil at a coating speed of 4 m / min and dried at 100±5℃. It is then subjected to room temperature roller pressing for 9 hours.

[0113] A multi-electrode structure is used for electrode fabrication;

[0114] The prepared electrode sheets and separators are wound together to form a bare battery cell.

[0115] The film is used for encapsulation and then baked at high temperature. The high temperature baking temperature is 85±1℃ and the time is 30h.

[0116] The three-electrode tabs are fabricated in a glove box. The materials used need to be baked at high temperature in an inert gas environment, at a temperature of 85±1℃ for 30 hours. The lithium sheet and the tabs are fixed together by winding a diaphragm to form a lithium replenishment electrode.

[0117] After the battery is filled with electrolyte, the lithium replenishment electrode is placed in a relatively closed seal for encapsulation.

[0118] After the battery has been left to stand and formed, it is placed on a dedicated lithium replenishment charging and discharging device. At this time, the Ni electrode is connected to the positive electrode of the device, and the lithium replenishment electrode is connected to the negative electrode of the device. The device adopts a discharge step with a discharge current of 0.1C and a discharge capacity designed to be 3% of the battery's design capacity.

[0119] After being recharged, the battery undergoes normal secondary sealing, capacity testing, edge folding, and other processes to complete the manufacturing process.

[0120] Example 6

[0121] Cathode precursor formulation and sheet preparation: LCO, SP and PVDF are dissolved in NMP at a mass ratio of 97:2:1 and stirred thoroughly for 10 hours to ensure uniform dispersion. The mixed slurry is then coated onto the surface of aluminum foil at a coating speed of 4 m / min, dried at 80°C, and then rolled at room temperature for 10 hours.

[0122] Negative electrode precursor formulation and sheet preparation: Graphite, silicon suboxide, SP, dispersant (CMC), and binder (SBR) are dissolved in deionized water in a ratio of 87.3:10:0.3:1.1:1.3 and stirred for 10 hours to achieve uniform dispersion. The mixed slurry is coated onto the surface of copper foil at a coating speed of 4 m / min and dried at 100±5℃. It is then subjected to room temperature roller pressing for 10 hours.

[0123] A multi-electrode structure is used for electrode fabrication;

[0124] The prepared electrode sheets and separators are wound together to form a bare battery cell.

[0125] The film is used for encapsulation and then baked at high temperature. The high temperature baking temperature is 85±1℃ and the time is 24h.

[0126] The three-electrode tabs are fabricated in a glove box. The materials used need to be baked at high temperature in an inert gas environment, at a temperature of 85±1℃ for 24 hours. The lithium sheet and the tabs are fixed together by wrapping a diaphragm to form a lithium replenishment electrode.

[0127] After the battery is filled with electrolyte, the lithium replenishment electrode is placed in a relatively closed seal for encapsulation.

[0128] After the battery has been left to stand and formed, it is placed on a dedicated lithium replenishment charging and discharging device. At this time, the Ni electrode is connected to the positive electrode of the device, and the lithium replenishment electrode is connected to the negative electrode of the device. The device adopts a discharge step with a discharge current of 0.1C and a discharge capacity designed to be 3% of the battery's design capacity.

[0129] After being recharged, the battery undergoes normal secondary sealing, capacity testing, edge folding, and other processes to complete the manufacturing process.

[0130] In summary, this invention fabricates a lithium replenishment electrode that can replenish lithium to both the positive and negative electrodes separately; the lithium source used for replenishment is a lithium sheet; the lithium replenishment electrode is placed inside a gas bag, which is retained during formation; the lithium replenishment step is performed after formation, and the amount of lithium replenished is calculated using current and time. This invention's method can precisely control the increase in coulombic efficiency, avoiding over-replenishment; it avoids the use of lithium powder for lithium battery replenishment, improving process safety compared to mainstream processes; and it has virtually no degradation to battery performance. Furthermore, this invention is also applicable to sodium-ion batteries for sodium replenishment, involving the same principles and processes.

[0131] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A method for replenishing lithium in a battery, characterized in that, include: Preparation of semi-finished lithium-ion batteries and preparation of lithium replenishment electrodes; The lithium replenishment electrode is placed in a gas bag filled with protective gas, and then the semi-finished lithium-ion battery is replenished with lithium. The lithium replenishment process includes: (1) Place the lithium replenishment electrode in the relative position of the seal on the semi-finished lithium-ion battery; (2) The lithium replenishment electrode is encapsulated in a gas bag filled with protective gas; (3) After the battery is left to stand and formed, it is placed in a charging and discharging device for lithium replenishment to complete the charging and discharging process.

2. The battery lithium replenishment method according to claim 1, characterized in that, The method for preparing semi-finished lithium-ion batteries includes: Step 1: Provide a current collector, and apply an active material onto the current collector using a gap or continuous coating method to prepare the positive electrode precursor and the negative electrode precursor respectively; Step 2: Fabricate the positive and negative electrode precursors prepared in Step 1 into a tab-centered or multi-tab structure to obtain the positive and negative electrode sheets. Step 3: The prepared positive and negative electrode sheets are wound together with the separator to form a positive bare cell and a negative bare cell, respectively; the separator is made by a wet process. Step 4: Encapsulate the positive and negative bare cells using aluminum-plastic film and then bake them. Step 5: After baking, inject electrolyte to obtain a semi-finished lithium-ion battery.

3. The battery lithium replenishment method according to claim 2, characterized in that, In step 1, the positive electrode precursor is prepared by dissolving lithium cobalt oxide, styrene-modified phenol, and polyvinylidene fluoride in NMP at a mass ratio of 97:2:1 and stirring for 8-10 hours to achieve uniform dispersion, thereby obtaining a mixed slurry. The mixed slurry is then coated onto the surface of the current collector aluminum foil at a coating speed of 4 m / min, dried at 80-120℃, and then rolled at room temperature for 1-48 hours to produce the positive electrode precursor.

4. The battery lithium replenishment method according to claim 2, characterized in that, In step 1, the negative electrode precursor is prepared by dissolving graphite, silicon suboxide, styrene-modified phenol, dispersant CMC, and binder in deionized water at a ratio of 87.3:10:0.3:1.1:1.3 and stirring for 8-10 hours to ensure uniform dispersion, thus obtaining a mixed slurry. The mixed slurry is then coated onto the surface of the current collector copper foil at a coating speed of 4 m / min and dried at 100±5℃. It is then subjected to room temperature roll pressing for 1-48 hours to produce the negative electrode precursor.

5. The battery lithium replenishment method according to claim 2, characterized in that, In step 4, the aluminum-plastic film is DNP113um; the baking temperature is 85±1℃, and the baking time is 24-72h.

6. The battery lithium replenishment method according to claim 1, characterized in that, The method for preparing the lithium supplementation electrode includes: Three-electrode tabs are fabricated in a glove box, and the materials used are baked in an inert gas environment; the lithium sheet and the tabs are fixed together by winding a diaphragm to obtain a lithium replenishment electrode; the diaphragm is made by a wet process.

7. The battery lithium replenishment method according to claim 1, characterized in that, In step (3), during charging and discharging, the Ni electrode is connected to the positive electrode of the device, and the lithium replenishment electrode is connected to the negative and / or positive electrode of the charging and discharging device. The device adopts the discharge step, the discharge current is 0.1C, and the discharge capacity is designed to be 3 to 6% of the battery design capacity.

8. The battery lithium replenishment method according to claim 1, characterized in that, The semi-finished lithium-ion batteries were replaced with semi-finished sodium-ion batteries, and the lithium replenishment method was replaced with the sodium replenishment method.

9. A battery prepared by a lithium replenishment method, characterized in that, A lithium-ion battery is manufactured using the lithium replenishment method according to any one of claims 1-7.

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