Lithium battery electrode sheet and activated lithium battery

Abstract

The present invention discloses a lithium battery electrode sheet, comprising a current collector, an electrode material coating, and a hot-melt film. The electrode material coating is applied to both sides of the current collector, and the hot-melt film is applied to the outside of the electrode material coating. The melting point of the hot-melt film is between 60°C and 160°C. The lithium battery electrode sheet is used as the positive or negative electrode sheet of the lithium battery. When the hot-melt film is not melted, it can block the transmission of lithium ions between the positive and negative electrodes. When the hot-melt film melts and shrinks, lithium ions can be transmitted between the positive and negative electrodes. The present invention also discloses an activated lithium battery. When stored at room temperature, the lithium ion transmission channel between the positive and negative electrodes is blocked, significantly reducing battery self-discharge. When the activated lithium battery is heated, the hot-melt film melts and shrinks, opening the lithium ion transmission channel between the positive and negative electrodes, and the activated lithium battery is activated. The present invention has the advantages of short activation time, long storage life, high specific energy, and large discharge rate.

Description

Technical Field

[0001] The invention belongs to the technical field of ammunition reserve lithium batteries and relates to a lithium battery electrode sheet and an activated lithium battery comprising the electrode sheet. Background Art

[0002] With the development of weaponry, the requirements for onboard power sources are becoming increasingly stringent, particularly for high energy density and long operating times. However, currently used batteries primarily rely on thermal batteries, which have a specific energy of less than 100Wh / kg and a short operating time, severely restricting the development of weaponry. Lithium batteries, with their high specific energy and long operating time, meet the requirements of medium-range, long-endurance missiles. However, their significant self-discharge makes them difficult to meet the 20-year reserve life requirement for missiles. Designing lithium batteries as reactivatable reserve batteries can extend their reserve life.

[0003] There are many ways to activate batteries, including thermal activation, electrolyte activation, seawater activation, etc. For lithium batteries, the main method currently used is to isolate the electrolyte and activate it by adding electrolyte.

[0004] Certain existing reserve lithium batteries include a housing, a cell and electrolyte within the housing, and a valve secured within the housing to isolate the cell and electrolyte. Under a predetermined acceleration, the electrolyte breaks through the valve and soaks into the cell, thereby achieving activation. However, both the positive electrode of a primary lithium battery and the positive and negative electrodes of a secondary lithium-ion battery suffer from high porosity and large thickness, making electrolyte soaking difficult and activation time long. This results in excessively high internal resistance and low current within a short period of time, making it difficult to meet the requirements of missiles and other equipment. Summary of the Invention

[0005] The object of the present invention is to overcome the above-mentioned defects and provide a lithium battery electrode sheet and an activated lithium battery, which solve the technical problem that existing lithium batteries are difficult to simultaneously meet the requirements of storage life and activation speed. The activated lithium battery of the present invention has the advantages of short activation time, long storage life, high specific energy and large discharge rate.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] A lithium battery electrode sheet, characterized by comprising a current collector, an electrode material coating and a hot-melt film;

[0008] The electrode material coating is applied on both sides of the current collector, and the hot-melt film is covered on the outside of the electrode material coating;

[0009] The melting point of the material used for hot melt film is 60-160°C;

[0010] The lithium battery electrode sheet is used as the positive electrode sheet or negative electrode sheet of the lithium battery. When the hot melt film is not melted, the hot melt film blocks the transmission of lithium ions between the positive electrode sheet and the negative electrode sheet. When the hot melt film is melted, the lithium ions are transmitted between the positive electrode sheet and the negative electrode sheet.

[0011] Furthermore, the thickness of the hot-melt film is 0.1 to 10 μm.

[0012] Furthermore, the porosity of the hot-melt film is ≤40%, the micropore radius is <0.2 nm (0.2 nm is the lithium ion solvation radius), and the preferred micropore radius is <76 pm (76 pm is the lithium ion radius).

[0013] Furthermore, the hot-melt film is an organic film;

[0014] The material used for the hot melt film is one or more of polypropylene, polyethylene, polyvinyl acetate, polystyrene, polyvinyl chloride, polycaprolactone, polybutadiene, polyethylene oxide, ethylene-vinyl acetate copolymer, polyvinyl butyral or polyethylene terephthalate.

[0015] Furthermore, when the lithium battery electrode sheet is a positive electrode sheet, the current collector is aluminum foil, and the active material in the electrode material coating is MnO2, FeS2, S or More than one of the following;

[0016] In the case of 0.3≤x1≤1,

[0017] In the equation, 0≤x2, y2≤1, x2+y2≤1, 0.3≤z2≤1;

[0018] In the equation, 0≤x3, y3≤1, x3+y3≤1, 0.3≤z3≤1;

[0019] In the case of 0.5≤x4≤1,

[0020] In the formula (a), M is one or more of Fe, Mn, Co or Ni, and 0≤x5≤1;

[0021] Medium, 0.5≤x6≤1;

[0022] In the equation, 2≤x7≤8, 5≤y7≤21.

[0023] Furthermore, when the lithium battery electrode sheet is a negative electrode sheet, the current collector is copper foil, and the active material in the electrode material coating is one or more of graphite, hard carbon, soft carbon, silicon carbon, silicon dioxide or metallic lithium.

[0024] Furthermore, the active material is or When more than one of the above is used, roller pressing and lithium removal treatment are performed after the electrode material coating is applied to the surface of the current collector;

[0025] When the active material is one or more of graphite, hard carbon, soft carbon, silicon carbon or silicon monoxide, the electrode material coating is coated on the surface of the current collector and then rolled and lithium-intercalated.

[0026] An activated lithium battery, wherein at least one of the positive electrode sheets or negative electrode sheets in the activated lithium battery is the above-mentioned lithium battery electrode sheet.

[0027] Furthermore, when stored at room temperature, the lithium ion transmission channel between the positive and negative electrodes is blocked;

[0028] When the activated lithium battery is heated, the hot-melt film melts and shrinks due to the heat, the lithium ion transmission channel between the positive electrode and the negative electrode is opened, and the activated lithium battery is activated.

[0029] Furthermore, it is assumed that the melting point of the material used for the hot-melt film is T0, and the heating temperature is T0+10~60°C.

[0030] Furthermore, the heating method of the activated lithium battery includes:

[0031] When there is no external power supply, a thermal battery is used to activate the lithium battery;

[0032] When there is an external power supply condition, the shell of the activated lithium battery is designed to be a steel shell, and the steel shell is heated by electromagnetic pulse intermittent heating, or a heating tape is attached to the outer surface of the steel shell;

[0033] The battery separator is one or more of PI, PP, PEEK, PET, PVDF or solid electrolyte membrane.

[0034] Compared with the prior art, the present invention has at least one of the following beneficial effects:

[0035] (1) The present invention creatively proposes a lithium battery electrode sheet that uses a hot-melt film in different states before and after melting, which can simultaneously meet the requirements of activated lithium batteries for reducing battery self-discharge, improving storage life, and rapid activation;

[0036] (2) Compared with other activation methods, the activated lithium battery prepared using the lithium battery electrode sheet of the present invention has the advantages of short activation time, simple battery structure, no weight occupation, high reliability, and low cost;

[0037] (3) The present invention realizes rapid activation of the battery by means of thermal activation, and the battery voltage can be detected before activation, which not only improves the storage life, but also ensures the detectability of the battery, improves the reliability, and meets the requirements of missile-borne use;

[0038] (4) Compared with thermal batteries, the activated lithium battery of the present invention has higher energy density and longer working time, and has a larger discharge rate than lithium primary batteries, filling the gap in high specific energy, long storage, long flight time and high power power supply on missiles. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A schematic diagram of a lithium battery electrode sheet of the present invention before activation;

[0040] Figure 2 A schematic diagram of a lithium battery electrode sheet of the present invention after activation;

[0041] Figure 3 This is a schematic diagram of a battery cell made of a lithium battery electrode sheet according to the present invention;

[0042] Figure 4 This is a schematic diagram of an activated lithium battery of the present invention;

[0043] In the figure, 1-hot-melt film, 2-electrode material coating, 3-current collector;

[0044] 10-positive electrode sheet, 11-positive electrode ear, 20-negative electrode sheet, 21-negative electrode ear, 30-battery case, 40-battery cap, 50-diaphragm, 100-battery cell. DETAILED DESCRIPTION

[0045] The following detailed description of the present invention will make the features and advantages of the present invention more clear and explicit.

[0046] The word "exemplary" is used exclusively herein to mean "serving as an example, example, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Although various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless otherwise indicated.

[0047] This invention utilizes a specially structured electrode sheet to design a rapidly activated reserve lithium battery. The electrode sheet is coated with a hot-melt film. After the battery is assembled, packaged, and filled with liquid, the internal resistance is extremely high, blocking the lithium ion transmission path between the electrode sheets. However, the battery voltage is detectable, significantly reducing self-discharge. To activate the battery, simply heat the battery to melt the hot-melt film, allowing lithium ions to flow between the positive and negative electrodes.

[0048] The lithium battery electrode sheet of the present invention comprises a current collector and an electrode material coating, which is further coated with a hot-melt film. The hot-melt film has a melting point of 60-160°C and a thickness of 0.1-10 μm. The thinner the film, the faster it melts upon heating and the shorter the activation time. The optimal melting point range is 60-100°C. The lower the melting point, the easier it is to reach the melting temperature and the less damage to the battery.

[0049] The current collector is aluminum foil or copper foil, and the electrode material coating comprises active material, conductive agent, binder and the like.

[0050] When the lithium battery electrode sheet is used as the positive electrode, the current collector is aluminum foil and the positive electrode active material is (0.3≤x1≤1), (0≤x2, y2≤1, x2+y2≤1, 0.3≤z2≤1), (0≤x3, y3≤1, x3+y3≤1, 0.3≤z3≤1), (0.5≤x4≤1), (0≤x6≤1), (0.5≤x6≤1), MnO2, FeS2, S, At least one of (2≤x7≤8, 5≤y7≤21).

[0051] The positive electrode active material is or Lithium-containing compounds such as aluminum and magnesium need to be delithiated after rolling.

[0052] When the lithium battery electrode sheet is used as the positive electrode, the binder includes but is not limited to PVDF and PTFE; the conductive agent includes but is not limited to at least one of SP, VGCF, CNT, KS6, acetylene black, and graphene.

[0053] When the lithium battery electrode sheet is used as the negative electrode, the current collector is copper foil, and the negative electrode active material is at least one of graphite, hard carbon, soft carbon, silicon carbon or silicon dioxide, metallic lithium and other materials.

[0054] When the negative electrode active material is graphite, hard carbon, soft carbon, silicon carbon or silicon oxide, the electrode material coating needs to be subjected to lithium insertion treatment after coating and rolling.

[0055] Preferably, if the active material is metallic lithium, no current collector is required.

[0056] When the lithium battery electrode sheet is used as the negative electrode, the binder includes but is not limited to one or more of PVDF, PTFE, SBR, CMC, and PAA; the conductive agent includes but is not limited to one or more of SP, VGCF, CNT, KS6, acetylene black, and graphene.

[0057] The lithium insertion method uses conventional positive electrode materials or metallic lithium that can insert and remove lithium ions to insert lithium into the negative electrode.

[0058] The electrode sheet current collector can also be made of metal lithium, nickel, steel, etc.

[0059] The hot-melt film is an organic film, and its materials include but are not limited to polypropylene, polyethylene, polyvinyl acetate, polystyrene, polyvinyl chloride, polycaprolactone, polybutadiene, polyethylene oxide, ethylene-vinyl acetate copolymer, polyvinyl butyral, and polyethylene terephthalate.

[0060] An activated lithium battery comprises the above-mentioned lithium battery electrode sheet, and the activation method is to rapidly heat the battery for 10-180 seconds at a temperature equal to the melting point of the hot-melt film plus 10-60°C.

[0061] For activation and heating methods for pop-up lithium batteries without external power supply, a thermal battery is preferred. After activation, the thermal battery reaches a high temperature, and this heat can be used to heat the lithium battery, achieving rapid activation. A thermal battery is a traditional pop-up battery characterized by a short discharge time, high power, and high temperature. The present invention can use this heat to heat the lithium battery for activation.

[0062] For spring-activated lithium batteries with external power supply, steel battery casings are preferred. Intermittent electromagnetic pulse heating is preferred to achieve rapid heating of the battery casing while preventing the battery from overheating. The battery casing temperature should be controlled within 150°C to allow heat to be transferred to the interior of the battery, melting the film. Rapid heating can also be achieved by attaching external heating tape.

[0063] The battery separators are preferably high temperature resistant separators such as PI, PP, PEEK, PET, PVDF and solid electrolyte membranes.

[0064] Before use, activated lithium batteries using the electrode sheet of the present invention have a hot-melt film separating the positive and negative electrodes. This prevents lithium ions from penetrating, resulting in extremely high internal resistance, which reduces battery self-discharge and improves storage life. The film is melted by heating before use to activate the battery. These activated lithium batteries have advantages such as fast activation time, simple structure, high specific energy, detectability, long storage life, and a wide range of trials. Their specific energy exceeds 200 Wh / kg, three times that of thermal batteries, and their discharge rate can reach up to 10C, far exceeding that of primary lithium batteries. They can be used as power sources for various missile weapons, torpedoes, space science equipment, ground equipment, and launch vehicles.

[0065] Furthermore, the present invention achieves rapid battery activation through thermal activation, and the battery voltage can be detected before activation. This pre-activation voltage detection allows the battery charge level to be determined, preventing launch failures caused by battery abnormalities. Thermal batteries used in similar missiles cannot detect voltage before activation, nor can they confirm battery health. The probability of failure is related to battery reliability. Therefore, the present invention not only improves reserve life, but also ensures battery detectability, enhancing reliability and meeting missile-borne use requirements.

[0066] The specific steps for preparing the above-mentioned lithium battery electrode sheet as a positive electrode sheet are as follows:

[0067] S1. Add the positive electrode active material, binder, conductive agent, etc. to NMP and mix them evenly to prepare positive electrode slurry, which is then evenly coated on aluminum foil to obtain a positive electrode material coating, and the positive electrode sheet is roll-pressed.

[0068] S2. If the positive electrode active material is Li x1 CoO2、Li z2 Ni 1-x2-y2 Co x2 Mn y2 O2、Li z3 Ni 1-x3-y3 Co x3 Al y3 O2、Li x4 Mn2O4 or Li x5 MPO4 and other lithium-containing compounds can be delithiated after the electrode sheet is coated and rolled. The treatment method uses conventional charging and delithiation methods, including separating the positive electrode from the negative electrode material such as metal lithium or graphite with a diaphragm, adding electrolyte, and charging. When the open circuit voltage of the positive electrode relative to the negative electrode reaches 4V~4.5V, the positive electrode sheet is cleaned and dried after completion. If the positive electrode active material is CF x6 , MnO2, FeS2, S, Cr x7 O y7 , without the need for delithiation.

[0069] S3. Coating the hot melt film on the surface of the positive electrode material coating. Preferably, the coating method includes but is not limited to hot pressing, rolling, spraying, roller coating, evaporation, vapor deposition, electrospinning, growth, physical coating, etc.;

[0070] S4, after rolling and slitting (die cutting), the positive electrode sheet is made.

[0071] The specific steps for preparing the above-mentioned lithium battery electrode sheet as the negative electrode sheet are as follows:

[0072] S1. Add the negative electrode active material, binder, and conductive agent to NMP or deionized water and mix them evenly to form a negative electrode slurry. The slurry is then evenly coated on copper foil to form a negative electrode material coating. The negative electrode sheet is then roll-pressed. If the negative electrode active material is metallic lithium, the slurrying and coating steps are not required.

[0073] S2. If the active material is at least one of graphite, hard carbon, soft carbon, silicon carbon, or silicon monoxide, a lithium intercalation treatment is required after the electrode sheet is coated and rolled. This treatment is performed using conventional methods, charging the electrode sheet with any lithium-ion-removable positive electrode sheet; or discharging the electrode sheet with metallic lithium to intercalate lithium ions into the electrode. After completion, the negative electrode sheet is cleaned and dried. If the negative electrode active material is metallic lithium, this process is not required.

[0074] S3. Coating the hot melt film on the surface of the negative electrode material coating. Coating methods include but are not limited to hot pressing, rolling, spraying, roller coating, evaporation, vapor deposition, electrospinning, growth, physical coating, etc.

[0075] S4. After rolling and slitting (die cutting), the negative electrode sheet is made.

[0076] An activated lithium battery, the specific preparation steps are as follows:

[0077] The positive electrode sheet, separator and negative electrode sheet are stacked or wound into a battery cell, and the battery is prepared after welding, packaging and liquid injection.

[0078] Example 1

[0079] This embodiment provides a lithium battery positive electrode sheet and an activated lithium battery containing the electrode sheet:

[0080] like Figure 1 The positive electrode sheet 10 of a lithium battery comprises a current collector 3, an electrode material coating 2 and a hot-melt film 1. The surface of the electrode material coating 2 is covered with a layer of hot-melt film 1. Figure 4 , an activated lithium battery, comprising a positive electrode sheet 10, a negative electrode sheet 20, a battery shell 30, a battery cap 40, a diaphragm 50, an electrolyte, a positive electrode ear 11, and a negative electrode ear 21.

[0081] (1) Preparation of positive electrode: NCA (LiNi 0.8 Co 0.15 Al 0.05 O2) was used as the positive electrode active material, mixed with the binder PVDF and the conductive agent Super-P in a mass ratio of 95:2:3 in NMP to form a positive electrode slurry. This was then coated on both sides of aluminum foil and roller-pressed to remove lithium, resulting in a delithiated positive electrode sheet. A 1 μm thick polycaprolactone film was roller-coated onto the surface of the positive electrode sheet to form the final positive electrode sheet 10.

[0082] (2) Preparation of lithium batteries:

[0083] 1) Negative electrode sheet 20: Graphite is used as the negative electrode active material, and is mixed and stirred uniformly with binders CMC and SBR in a mass ratio of 97:1.5:1.5 in deionized water to form a negative electrode slurry, which is then coated on both sides of copper foil and rolled to insert lithium to form the negative electrode sheet 20;

[0084] 2) Diaphragm 50: A PI diaphragm with a thickness of 20 μm is used;

[0085] 3) Production of battery cell 100: The positive electrode sheet 10, separator 50 and negative electrode sheet 20 obtained above are welded to the positive electrode ear 11 and the negative electrode ear 21 by using a winding and welding integrated machine and wound to obtain a lithium ion battery cell 100, as shown in FIG. Figure 3 ;

[0086] 4) Inject electrolyte and finally seal the battery;

[0087] (3) Battery activation and testing: After the battery is filled and left for 48 hours, use an internal resistance meter to measure the battery voltage and internal resistance. Wrap the battery with a heating device, quickly heat the battery to 120°C and stop heating. Discharge the battery at 1C. After discharge, measure the battery voltage and internal resistance. The battery design capacity is 2Ah.

[0088] Example 2

[0089] This embodiment provides a lithium battery positive electrode sheet and an activated lithium battery containing the electrode sheet:

[0090] A lithium battery positive electrode sheet 10 includes a current collector 3, an electrode material coating 2, and a hot-melt film 1. The electrode material coating 2 is covered with a layer of hot-melt film 1. An activated lithium battery includes a positive electrode sheet 10, a negative electrode sheet 20, a battery casing 30, a battery cap 40, a separator 50, an electrolyte, a positive tab 11, and a negative tab 21.

[0091] (1) Preparation of positive electrode sheet: CFx (x = 0.8) was used as the positive electrode active material, mixed with binder LA133, conductive agent Super-P, and CNT in a mass ratio of 95:2:2:1 in deionized water to form a positive electrode slurry, which was then coated on both sides of aluminum foil and rolled and slit to obtain a positive electrode sheet. A 1 μm thick polycaprolactone film was roll-coated on the surface of the positive electrode sheet to finally produce a positive electrode sheet 10;

[0092] (2) Preparation of lithium batteries:

[0093] 1) Negative electrode sheet 20: A lithium metal ribbon is used as the negative electrode active material and is made into a specific width and thickness to form the negative electrode sheet 20;

[0094] 2) Diaphragm 50: A PI diaphragm with a thickness of 20 μm is used;

[0095] 3) Production of the battery cell 100: The positive electrode sheet 10, the separator 50, and the negative electrode sheet 20 obtained above are welded to the positive electrode tab 11 and the negative electrode tab 21 using a winding and welding integrated machine, and then wound to obtain the lithium-ion battery cell 100;

[0096] 4) Inject electrolyte and finally seal the battery;

[0097] (3) Battery activation and testing: After the battery is filled and left for 48 hours, the battery voltage and internal resistance are measured with an internal resistance meter. The battery is wrapped with a heating device, quickly heated to 100°C and then stopped heating. The battery is discharged at 0.05C. After discharge, the battery voltage and internal resistance are measured. The battery design capacity is 6Ah.

[0098] Example 3

[0099] This embodiment provides a lithium battery negative electrode sheet and an activated lithium battery containing the electrode sheet:

[0100] A lithium battery negative electrode sheet 20 includes a current collector 3, an electrode material coating 2, and a hot-melt film 1. The electrode material coating 2 is covered with a layer of hot-melt film 1. An activated lithium battery includes a positive electrode sheet 10, a negative electrode sheet 20, a battery casing 30, a battery cap 40, a separator 50, an electrolyte, a positive tab 11, and a negative tab 21.

[0101] (1) Preparation of negative electrode sheet: Graphite is used as the negative electrode active material, and the binder CMC and SBR are mixed and stirred in deionized water at a mass ratio of 97:1.5:1.5 to form a negative electrode slurry, which is then coated on both sides of copper foil. After roller-pressing and lithium insertion, a lithium-inserted negative electrode sheet is prepared. A 1 μm thick polycaprolactone film is roller-coated on the surface of the negative electrode sheet to finally form a negative electrode sheet 20;

[0102] (2) Preparation of lithium batteries:

[0103] 1) Positive electrode 10: NCA (LiNi 0.8 Co 0.15 Al 0.05 O2) is a positive electrode active material, which is mixed with a binder PVDF and a conductive agent Super-P in a mass ratio of 95:2:3 in NMP to form a positive electrode slurry, which is then coated on both sides of an aluminum foil and rolled to remove lithium to obtain a delithiated positive electrode sheet 10;

[0104] 2) Diaphragm 50: A PI diaphragm with a thickness of 20 μm is used;

[0105] 3) Production of the battery cell 100: The positive electrode sheet 10, the separator 50, and the negative electrode sheet 20 obtained above are welded to the positive electrode tab 11 and the negative electrode tab 21 using a winding and welding integrated machine, and then wound to obtain the lithium-ion battery cell 100;

[0106] 4) Inject electrolyte and finally seal the battery;

[0107] (3) Battery activation and testing: After the battery is filled and left for 48 hours, use an internal resistance meter to measure the battery voltage and internal resistance. Wrap the battery with a heating device, quickly heat the battery to 120°C and stop heating. Discharge the battery at 1C. After discharge, measure the battery voltage and internal resistance. The battery design capacity is 2Ah.

[0108] Example 4

[0109] This embodiment provides a lithium battery negative electrode sheet and an activated lithium battery containing the electrode sheet:

[0110] A lithium battery negative electrode sheet 20 includes a collector fluid 3, an electrode material coating 2, and a hot-melt film 1. The electrode material coating 2 is covered with a layer of hot-melt film 1. An activated lithium battery includes a positive electrode sheet 10, a negative electrode sheet 20, a battery casing 30, a battery cap 40, a separator 50, an electrolyte, a positive tab 11, and a negative tab 21.

[0111] (1) Preparation of negative electrode sheet: Using metallic lithium as the negative electrode active material, a sheet of a specific width and thickness is prepared, and a 1 μm thick polycaprolactone film is rolled onto the surface of the negative electrode sheet to finally form a negative electrode sheet 20;

[0112] (2) Preparation of lithium batteries:

[0113] 1) Positive electrode 10: NCA (LiNi 0.8 Co 0.15 Al 0.05 O2) is a positive electrode active material, which is mixed with a binder PVDF and a conductive agent Super-P in a mass ratio of 95:2:3 in NMP to form a positive electrode slurry, which is then coated on both sides of an aluminum foil and rolled to remove lithium to obtain a delithiated positive electrode sheet 10;

[0114] 2) Diaphragm 50: A PI diaphragm with a thickness of 20 μm is used;

[0115] 3) Production of the battery cell 100: The positive electrode sheet 10, the separator 50, and the negative electrode sheet 20 obtained above are welded to the positive electrode tab 11 and the negative electrode tab 21 using a winding and welding integrated machine, and then wound to obtain the lithium-ion battery cell 100;

[0116] 4) Inject electrolyte and finally seal the battery;

[0117] (3) Battery activation and testing: After the battery is filled and left for 48 hours, the battery voltage and internal resistance are measured with an internal resistance meter. The battery is wrapped with a heating device, quickly heated to 100°C and then stopped heating. The battery is discharged at 1C. After discharge, the battery voltage and internal resistance are measured. The battery design capacity is 2Ah.

[0118] Comparative Example 1

[0119] Preparation of lithium batteries:

[0120] 1) Positive electrode 10: NCA (LiNi 0.8 Co 0.15 Al 0.05 O2) is a positive electrode active material, which is mixed with a binder PVDF and a conductive agent Super-P in a mass ratio of 95:2:3 in NMP to form a positive electrode slurry, which is then coated on both sides of an aluminum foil and rolled to obtain a positive electrode sheet 10;

[0121] 2) Preparation of negative electrode sheet: Graphite is used as the negative electrode active material, and is mixed with binder CMC and SBR in a mass ratio of 97:1.5:1.5 in deionized water to form a negative electrode slurry, which is then coated on both sides of copper foil and rolled to form a negative electrode sheet 20;

[0122] 3) Separator 50: a PI separator with a thickness of 20 μm;

[0123] 4) Production of the battery cell 100: The positive electrode sheet 10, separator 50, and negative electrode sheet 20 obtained above are welded to the positive electrode tab 11 and the negative electrode tab 21 using a winding and welding integrated machine, and then wound to obtain the lithium-ion battery cell 100;

[0124] 5) Inject electrolyte and finally seal the battery;

[0125] 6) After the battery is filled and left for 48 hours, it is subjected to 0.1C formation treatment. After formation, it is discharged at 1C. The battery design capacity is 2Ah.

[0126] Comparative Example 2

[0127] A battery was prepared according to the method of Example 4, except that there was no hot-melt film on the surface of the negative electrode and no activation was required. After the battery was prepared, 1C discharge was performed and the battery design capacity was 2Ah.

[0128] Comparative Example 3

[0129] (1) Preparation of lithium batteries:

[0130] 1) A battery was prepared according to the method of Comparative Example 1;

[0131] 2) After the battery is fully charged, the internal electrolyte is removed by DMC cleaning, low-temperature drying, etc.

[0132] (2) Battery activation and testing: Inject electrolyte into the battery through the reserved injection hole, wait for a certain period of time and then discharge at 1C. After discharge, measure the battery voltage and internal resistance. The battery design capacity is 2Ah.

[0133] The batteries prepared in Examples 1 to 4 and Comparative Examples 1 to 3 were tested, and the activation time from the start of activation to normal discharge was calculated. The open circuit voltage, internal resistance, discharge capacity, and discharge capacity after one year of open circuit storage at room temperature were measured, as shown in Table 1. In Table 1, P indicates that the electrode contains a hot-melt film.

[0134] Table 1 Battery test results of Examples 1 to 4 and Comparative Example 1

[0135]

[0136]

[0137] As can be seen from the above table, Comparative Example 1 is a conventional lithium-ion battery design with no hot-melt film on the electrode surface. Therefore, its internal resistance after formation is low, and the battery can work directly after being connected to the load without activation. However, the annual capacity retention rate of the battery is only 92.6%, and the self-discharge is large.

[0138] The difference between Comparative Example 2 and Comparative Example 1 is that the negative electrode uses metallic lithium, its lithium capacity is excessive, and the side reaction after lithium passivation is smaller than that of the graphite negative electrode, so its self-discharge is smaller than that of the graphite negative electrode, and the annual capacity retention rate can reach 95%, but it still does not meet the requirements for use on a bullet.

[0139] Comparative Example 3 achieves long-term storage by isolating the electrolyte and activating the battery by adding electrolyte, a traditional lithium-ion battery activation method. Due to the high porosity of the separator and electrode materials, the electrolyte infiltration is slow after injection, and discharge performance improves over time. Therefore, it is impossible to achieve the expected performance in a short period of time. Even after more than 1200 seconds, the discharge capacity is still far below the designed capacity. To accurately test the capacity retention rate after one year of storage, the battery was left to rest for 16 hours after activation, at which point the capacity retention rate reached 98.5%.

[0140] In Examples 1 to 4, different types of activated lithium batteries are made by respectively using lithium batteries with different positive electrode materials and different negative electrode materials, combined with hot-melt films on the electrode surfaces. In Example 1, for conventional lithium-ion battery systems, a hot-melt film is provided on the surface of the positive electrode to hinder the transfer of lithium ions between the positive and negative electrodes. However, due to the introduction of this film, the battery cannot be formed like a conventional lithium-ion battery, so the positive electrode needs to be delithiated and the negative electrode needs to be lithium-embedded before the battery is prepared. It should be noted that the hot-melt film plays the same role whether it is on the positive electrode or the negative electrode, which is to hinder the transfer of lithium ions, thereby reducing self-discharge. Figure 2 By heating the ultra-thin non-porous hot-melt film at high temperature to melt and shrink, a lithium ion transmission channel is formed, which can activate the battery.

[0141] Compared with Example 1, Example 3 replaces the hot-melt film to the negative electrode, and the effect is consistent with that of Example 1.

[0142] Compared with Example 3, Example 4 replaces the negative electrode. The advantage is that the process is simpler and the negative electrode does not need lithium insertion treatment, but the disadvantage is that the rate performance and safety performance will be reduced.

[0143] Compared with Example 4, Example 2 replaces the positive electrode and replaces the hot-melt film to the positive electrode. The advantage is that the positive electrode uses a lithium-free positive electrode material and does not require delithiation treatment. At the same time, the negative electrode uses metallic lithium, and the battery process is simpler. An activated lithium carbon fluoride battery is produced, which has the advantages of high specific energy, long storage life, and simple activation.

[0144] The present invention has been described in detail above with reference to specific embodiments and exemplary examples. However, these descriptions should not be construed as limiting the present invention. Those skilled in the art will appreciate that various equivalent substitutions, modifications, or improvements may be made to the technical solutions and implementations of the present invention without departing from the spirit and scope of the present invention, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be determined by the appended claims.

[0145] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. An activated lithium battery, characterized in that: The positive electrode and / or negative electrode in the activated lithium battery are lithium battery electrode sheets; Lithium battery electrode sheets include current collectors, electrode material coatings, and hot-melt films; The electrode material coating is applied on both sides of the current collector, and the hot-melt film is covered on the outside of the electrode material coating; The melting point of the material used for hot melt film is 60-160°C; When the hot-melt film is not melted, the hot-melt film blocks the transfer of lithium ions between the positive electrode sheet and the negative electrode sheet. When the hot-melt film is melted, the lithium ions are transferred between the positive electrode sheet and the negative electrode sheet. Hot melt film is an organic film; The material used for the hot melt film is one or more of polypropylene, polyethylene, polyvinyl acetate, polystyrene, polyvinyl chloride, polycaprolactone, polybutadiene, polyethylene oxide, ethylene-vinyl acetate copolymer, polyvinyl butyral or polyethylene terephthalate; When stored at room temperature, the lithium ion transmission channel between the positive and negative electrodes is blocked; When the activated lithium battery is heated, the hot-melt film melts and shrinks due to the heat, the lithium ion transmission channel between the positive electrode and the negative electrode is opened, and the activated lithium battery is activated; Assume that the melting point of the material used for the hot melt film is T0, and the heating temperature is T0+10~60℃.

2. An activated lithium battery according to claim 1, characterized in that: The thickness of the hot-melt film is 0.1 to 10 μm.

3. An activated lithium battery according to claim 1, characterized in that: The porosity of the hot-melt film is ≤40%, and the micropore radius is <0.2nm.

4. An activated lithium battery according to claim 1, characterized in that: When the lithium battery electrode sheet is a positive electrode sheet, the current collector is aluminum foil, and the active material in the electrode material coating is MnO2, FeS2, S or More than one of the following; In the case of 0.3≤x1≤1, In the equation, 0≤x2, y2≤1, x2+y2≤1, 0.3≤z2≤1; In the equation, 0≤x3, y3≤1, x3+y3≤1, 0.3≤z3≤1; In the case of 0.5≤x4≤1, In the formula (a), M is one or more of Fe, Mn, Co or Ni, and 0≤x5≤1; Medium, 0.5≤x6≤1; In the equation, 2≤x7≤8, 5≤y7≤21.

5. An activated lithium battery according to claim 4, characterized in that: When the lithium battery electrode sheet is a negative electrode sheet, the current collector is copper foil, and the active material in the electrode material coating is one or more of graphite, hard carbon, soft carbon, silicon carbon, silicon dioxide or metallic lithium.

6. An activated lithium battery according to claim 5, characterized in that: The active material is or When more than one of the above is used, roller pressing and lithium removal treatment are performed after the electrode material coating is applied to the surface of the current collector; When the active material is one or more of graphite, hard carbon, soft carbon, silicon carbon or silicon monoxide, the electrode material coating is coated on the surface of the current collector and then rolled and lithium-intercalated.

7. An activated lithium battery according to claim 1, characterized in that: Heating methods for activated lithium batteries include: When there is no external power supply, a thermal battery is used to activate the lithium battery; When there is an external power supply condition, the shell of the activated lithium battery is designed to be a steel shell, and the steel shell is heated by electromagnetic pulse intermittent heating, or a heating tape is attached to the outer surface of the steel shell; The battery separator is one or more of PI, PP, PEEK, PET, PVDF or solid electrolyte membrane.

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