A method for manufacturing a high-performance cylindrical lithium primary battery

Abstract

The present application relates to a kind of chemical battery field, especially to a kind of preparation method of high-performance cylindrical lithium primary battery.It includes the positive electrode slurry containing active material is uniformly coated on positive electrode current collector in turn, is baked after rolling, and is cut to prepare positive electrode sheet etc., and the preparation method is finally pre-discharge process;The pre-discharge step is in turn (1) setting first cut-off voltage, second cut-off voltage, first constant current, second constant current;(2) lithium primary battery is loaded first constant current and is discharged with constant current at both ends, when lithium primary battery voltage reaches first cut-off voltage, stop discharging;(3) after 5-8 minutes of lithium primary battery, load second constant current and discharge with constant current, when lithium primary battery voltage reaches second cut-off voltage, stop discharging, (4) after 4-8 times of cycle discharge of repeating step (3), end pre-discharge treatment.The present application makes the discharge performance and storage performance of cylindrical lithium primary battery more excellent.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of chemical batteries, in particular to a preparation method of high-performance cylindrical lithium primary battery. BACKGROUND

[0002] With the decline of traditional chemical energy and the development of science and technology, lithium battery as the most potential alternative energy has been widely concerned. Lithium primary battery with metal lithium as negative electrode has the characteristics of high specific energy, stable discharge voltage, wide working temperature range, low self-discharge rate, etc. As early as in the 1990s, it has been widely used in industry, civil and military fields. Small and medium capacity lithium primary battery is suitable for small power equipment such as remote controller, camera and calculator, and high capacity lithium primary battery is more suitable for large industrial equipment and military facilities. However, with the increasing demand for energy in many fields, the performance requirements for lithium primary battery are also increasing, therefore, the discharge performance and storage performance of lithium primary battery are crucial.

[0003] The manufacturing method of cylindrical lithium primary battery is generally as follows: the positive electrode slurry containing active material is uniformly coated on the positive electrode current collector, and after baking and rolling, it is cut into positive electrode sheets with fixed size, then the positive electrode sheet, lithium strip negative electrode sheet and separator are wound together to form an electric core, which is put into a battery steel shell, electrolyte is injected and double sealing is performed, and the assembly of the battery is completed. After the assembly of the battery is completed, it must be pre-discharged, and for the discharge performance and storage performance of lithium primary battery, an excellent pre-discharge method is essential.

[0004] Currently, the pre-discharge methods generally have constant current pre-discharge, constant resistance pre-discharge and direct short circuit pre-discharge. The commonly used pre-discharge method is constant current pre-discharge. This method is to load a constant current on both ends of the battery within a constant time, and complete the pre-discharge by discharging a constant capacity. It is generally divided into one-step method or two-step method. One-step method is direct constant current discharge, and pre-discharge is completed after stopping. Two-step method first discharges the battery with constant current, and then discharges it with constant current again after a period of time. Chinese invention patent application CN113501550A discloses a two-step method for preparing core-shell composite sulfide material. A uniform distribution of metal cobalt layer is formed on the surface of FeS2 powder particles by chemical plating method to obtain a precursor material; then the precursor material is subjected to sulfurization treatment; and the core-shell composite sulfide material is obtained. When the shell cobalt disulfide prepared by the present application accounts for 2.5-14.6% of the total mass of the core-shell composite sulfide material, the core-shell composite positive electrode material is used as the positive electrode material; after assembling into a thermal battery, the thermal battery is discharged with constant current at a working temperature of 520°C and a current density of 200mA / cm2, and the cut-off voltage is 1.6V, and the specific capacity is as high as 331mAh / g. Although this constant current pre-discharge method can improve the storage performance of the battery to a certain extent, the number of pre-discharge is too small, and the gas generated by the reaction of impurities or moisture in the battery internal positive plate, lithium strip negative plate and electrolyte with lithium strip cannot be eliminated to a greater extent, thereby affecting the electrical performance and service life of the battery. SUMMARY

[0005] In view of the above technical defects, the present application provides a preparation method of high-performance cylindrical lithium primary battery.

[0006] To solve the above technical problems, the technical scheme used by the present application is as follows: a preparation method of high-performance cylindrical lithium primary battery, which comprises the following steps in sequence: uniformly coating positive electrode slurry containing active material on positive electrode current collector, baking and rolling, and then cutting to prepare positive electrode plate; then winding the positive electrode plate, lithium strip negative plate and separator together to form an electric core; placing the electric core into a battery steel shell body, injecting electrolyte and sealing twice, and finally performing pre-discharge process; the pre-discharge step is in sequence

[0007] (1) setting first cut-off voltage, second cut-off voltage, first constant current and second constant current;

[0008] (2) loading first constant current on both ends of lithium primary battery for constant current discharge, and stopping discharging when the voltage of lithium primary battery reaches first cut-off voltage;

[0009] (3) after standing lithium primary battery for 5-8 minutes, loading second constant current for constant current discharge, and stopping discharging when the voltage of lithium primary battery reaches second cut-off voltage,

[0010] (4) After repeating step (3) for 4-8 cycles of discharging, the pre-discharge treatment is completed.

[0011] The room temperature is maintained during the pre-discharge process. During the pre-discharge process, the high current impact can reduce the internal resistance of the battery, and the high activity of the iron disulfide can be fully consumed by multiple constant current discharges, so that the internal resistance of the battery is consistent; the high voltage is reduced by setting the cut-off voltage, and the voltage is consistent. Therefore, after the pre-discharge step, the consistency of the battery performance is enhanced.

[0012] Further: In the preparation method of the high-performance cylindrical lithium primary battery, the discharge amount of the pre-discharge is at least 4% of the battery capacity. Preferably: the discharge amount of the pre-discharge is 4%-6% of the battery capacity, under this condition, the battery discharge performance is better, and the battery consistency is better.

[0013] The two sealing refers to that the cylindrical battery with the cell and the electrolyte and the assembled cap is put into an automatic guide slot, sent into a sealing mold, and one sealing is completed; after cleaning, it is put into an automatic guide slot, sent into a second sealing mold, and the second sealing is completed.

[0014] Further: In the preparation method of the high-performance cylindrical lithium primary battery, the cylindrical lithium primary battery is a lithium iron disulfide battery or a lithium manganese dioxide battery.

[0015] The first cut-off voltage of the lithium iron disulfide battery pre-discharge is 1.35-1.50V, and the second cut-off voltage is 1.50-1.70V; the first constant current discharge current of the lithium iron disulfide battery pre-discharge is 500-1500mA, and the second constant current discharge current is 100-500mA. Preferably, the first cut-off voltage of the lithium iron disulfide battery pre-discharge is 1.38-1.48V, and the second cut-off voltage is 1.52-1.66V; the first constant current discharge current of the lithium iron disulfide battery pre-discharge is 800-1200mA, and the second constant current discharge current is 200-500mA.

[0016] The material composition of the positive plate of the lithium iron disulfide battery is iron disulfide 70-85wt%, conductive agent 4-11wt%, binder 4-10wt%, and positive electrode additive 4-10wt%, and the sum of each component is 100%. The conductive agent is at least one of graphite and acetylene black; the binder is at least one of polyvinylidene fluoride and polytetrafluoroethylene.

[0017] The first cut-off voltage of the lithium-manganese dioxide battery pre-discharge is 2.30-2.65V, and the second cut-off voltage is 2.70-3.00V; the first constant current of the lithium-manganese dioxide battery pre-discharge is 500-1600mA, and the second constant current is 100-600mA. Preferably, the first cut-off voltage of the lithium-manganese dioxide battery pre-discharge is 2.40-2.60V, and the second cut-off voltage is 2.80-3.00V; the first constant current of the lithium-manganese dioxide battery pre-discharge is 1150-1550mA, and the second constant current is 100-300mA.

[0018] The composition of the positive electrode sheet of the lithium-manganese dioxide battery is 85-95wt% of manganese dioxide, 2-7wt% of conductive agent, and 3-8wt% of binder. The conductive agent is at least one of graphite and acetylene black; and the binder is at least one of polyacrylate and polytetrafluoroethylene.

[0019] Compared with the prior art, the preparation method of the above-mentioned high-performance cylindrical lithium primary battery comprises the following steps in sequence: uniformly coating positive electrode slurry containing active material on the positive electrode current collector, baking and rolling, and then cutting to prepare the positive electrode sheet; then winding the positive electrode sheet, lithium strip negative electrode sheet and separator together to form the battery cell; placing the battery cell in the battery steel shell housing, injecting electrolyte and twice sealing, and finally performing the pre-discharge process; the pre-discharge step comprises the following steps in sequence:

[0020] (1) setting the first cut-off voltage, the second cut-off voltage, the first constant current and the second constant current;

[0021] (2) loading the first constant current on both ends of the lithium primary battery to perform constant current discharge, and stopping the discharge when the voltage of the lithium primary battery reaches the first cut-off voltage;

[0022] (3) after 5-8 minutes of standing of the lithium primary battery, loading the second constant current to perform constant current discharge, and stopping the discharge when the voltage of the lithium primary battery reaches the second cut-off voltage,

[0023] (4) repeating step (3) for 4-8 times of cycle discharge, and ending the pre-discharge treatment.

[0024] The application is pre-discharged by setting the cut-off voltage, and the battery is discharged under the loading of a larger constant current. When the voltage drops to the set cut-off voltage, the battery is left for a period of time, and then constant current discharge is performed again. When the voltage drops to the cut-off voltage, the battery is left for a period of time again. After the repeated constant current discharge for multiple times, the gas generated by the reaction of the positive plate, electrolyte impurities or moisture in the battery with lithium can be eliminated to the maximum extent, the internal pressure of the battery is reduced, the storage performance of the battery is improved, the internal resistance caused by the negative passivation layer is reduced, the battery voltage is basically consistent, and the electrical performance of the battery is improved. The application solves the problem of inconsistent electrical performance of cylindrical lithium primary batteries, improves the discharge performance and storage performance of the battery, and further promotes the application of the battery. The application makes the discharge performance and storage performance of the cylindrical lithium primary battery more excellent. DETAILED DESCRIPTION

[0025] The main idea of the application is to pre-discharge by setting the cut-off voltage, and the battery is discharged under the loading of a larger constant current. When the voltage drops to the set cut-off voltage, the battery is left for a period of time, and then constant current discharge is performed again. When the voltage drops to the cut-off voltage, the battery is left for a period of time again. After the repeated constant current discharge for multiple times, the gas generated by the reaction of the positive plate, electrolyte impurities or moisture in the battery with lithium can be eliminated to the maximum extent, the internal pressure of the battery is reduced, the storage performance of the battery is improved. The content of the application will be further described in combination with the examples. The content mentioned in the examples is not a limitation of the application, and the selection of each raw material in the material has no substantial influence on the results.

[0026] Example 1

[0027] High-performance lithium iron disulfide batteries are manufactured and pre-discharged to evaluate the discharge performance and storage performance under various constant current discharge systems.

[0028] Preparation of lithium iron disulfide battery positive plate: the positive electrode slurry and the positive electrode current collector are coated by a coating machine, and then baked, rolled, and cut to form the positive plate. The composition of the positive electrode slurry is as follows: iron disulfide 76wt%, conductive agent graphite 6wt%, conductive agent acetylene black 4wt%, binder polyvinylidene fluoride 4wt%, binder polytetrafluoroethylene 4wt%, additive calcium oxide 3wt%, and additive silicon dioxide 3wt%.

[0029] Preparation of lithium iron disulfide battery: the prepared positive plate, lithium strip negative plate, and separator are wound together to form an electric core, which is placed in a battery steel shell, injected with electrolyte, sealed twice, and finally pre-discharged to form a high-performance lithium iron disulfide battery of FR14505 type.

[0030] The lithium iron disulfide battery pre-discharge step is: (1) setting the first cut-off voltage to 1.38 V, the second cut-off voltage to 1.52 V, the first constant current to 800 mA, and the second constant current to 200 mA, (2) loading the first constant current on both ends of the battery to perform constant current discharge, (3) stopping the discharge when the battery voltage reaches the first cut-off voltage, (4) resting for 5 min, (5) loading the second constant current to perform constant current discharge on the battery, (6) stopping the discharge when the battery voltage reaches the second cut-off voltage, and repeating steps (4), (5), and (6) to perform 4 times of discharging on the battery, and ending the pre-discharge.

[0031] Example 2

[0032] The positive electrode sheet and the lithium iron disulfide battery are prepared according to the method described in Example 1.

[0033] The lithium iron disulfide battery pre-discharge step is: (1) setting the first cut-off voltage to 1.38 V, the second cut-off voltage to 1.52 V, the first constant current to 800 mA, and the second constant current to 200 mA, (2) loading the first constant current on both ends of the battery to perform constant current discharge, (3) stopping the discharge when the battery voltage reaches the first cut-off voltage, (4) resting for 5 min, (5) loading the second constant current to perform constant current discharge on the battery, (6) stopping the discharge when the battery voltage reaches the second cut-off voltage, and repeating steps (4), (5), and (6) to perform 4 times of discharging on the battery, and ending the pre-discharge.

[0034] Example 3

[0035] The positive electrode sheet and the lithium iron disulfide battery are prepared according to the method described in Example 1.

[0036] The lithium iron disulfide battery pre-discharge step is: (1) setting the first cut-off voltage to 1.38 V, the second cut-off voltage to 1.52 V, the first constant current to 800 mA, and the second constant current to 200 mA, (2) loading the first constant current on both ends of the battery to perform constant current discharge, (3) stopping the discharge when the battery voltage reaches the first cut-off voltage, (4) resting for 5 min, (5) loading the second constant current to perform constant current discharge on the battery, (6) stopping the discharge when the battery voltage reaches the second cut-off voltage, and repeating steps (4), (5), and (6) to perform 4 times of discharging on the battery, and ending the pre-discharge.

[0037] Example 4

[0038] The positive electrode sheet and the lithium iron disulfide battery are prepared according to the method described in Example 1.

[0039] Lithium iron disulfide battery pre-discharge procedure: (1) set the first cut-off voltage to 1.44 V, the second cut-off voltage to 1.66 V, the first constant current to 1000 mA, the second constant current to 500 mA, (2) load the first constant current across the battery to perform constant current discharge, (3) stop discharging when the battery voltage reaches the first cut-off voltage, (4) rest for 8 min, (5) load the second constant current to perform constant current discharge on the battery, (6) stop discharging when the battery voltage reaches the second cut-off voltage, perform the cycle of steps (4), (5), (6), after discharging the battery for 6 times, end the pre-discharge.

[0040] Example 5

[0041] Prepare the positive electrode sheet and lithium iron disulfide battery according to the method described in Example 1.

[0042] Lithium iron disulfide battery pre-discharge procedure: (1) set the first cut-off voltage to 1.44 V, the second cut-off voltage to 1.58 V, the first constant current to 1000 mA, the second constant current to 500 mA, (2) load the first constant current across the battery to perform constant current discharge, (3) stop discharging when the battery voltage reaches the first cut-off voltage, (4) rest for 8 min, (5) load the second constant current to perform constant current discharge on the battery, (6) stop discharging when the battery voltage reaches the second cut-off voltage, perform the cycle of steps (4), (5), (6), after discharging the battery for 8 times, end the pre-discharge.

[0043] Example 6

[0044] Prepare the positive electrode sheet and lithium iron disulfide battery according to the method described in Example 1.

[0045] Lithium iron disulfide battery pre-discharge procedure: (1) set the first cut-off voltage to 1.44 V, the second cut-off voltage to 1.66 V, the first constant current to 800 mA, the second constant current to 200 mA, (2) load the first constant current across the battery to perform constant current discharge, (3) stop discharging when the battery voltage reaches the first cut-off voltage, (4) rest for 5 min, (5) load the second constant current to perform constant current discharge on the battery, (6) stop discharging when the battery voltage reaches the second cut-off voltage, perform the cycle of steps (4), (5), (6), after discharging the battery for 4 times, end the pre-discharge.

[0046] Example 7

[0047] Prepare the positive electrode sheet and lithium iron disulfide battery according to the method described in Example 1.

[0048] The lithium iron disulfide battery pre-discharge procedure was as follows: (1) set the first cut-off voltage to 1.48 V, the second cut-off voltage to 1.58 V, the first constant current to 1200 mA, and the second constant current to 400 mA, (2) load the first constant current across the battery to perform constant current discharge, (3) stop discharging when the battery voltage reaches the first cut-off voltage, (4) rest for 8 min, (5) load the second constant current to perform constant current discharge on the battery, (6) stop discharging when the battery voltage reaches the second cut-off voltage, and repeat steps (4), (5), and (6) for 8 times of discharging on the battery, and then end the pre-discharge.

[0049] Example 8

[0050] The positive electrode sheet and lithium iron disulfide battery were prepared according to the method described in Example 1.

[0051] The lithium iron disulfide battery pre-discharge procedure was as follows: (1) set the first cut-off voltage to 1.48 V, the second cut-off voltage to 1.58 V, the first constant current to 1200 mA, and the second constant current to 400 mA, (2) load the first constant current across the battery to perform constant current discharge, (3) stop discharging when the battery voltage reaches the first cut-off voltage, (4) rest for 8 min, (5) load the second constant current to perform constant current discharge on the battery, (6) stop discharging when the battery voltage reaches the second cut-off voltage, and repeat steps (4), (5), and (6) for 8 times of discharging on the battery, and then end the pre-discharge.

[0052] Example 9

[0053] The positive electrode sheet and lithium iron disulfide battery were prepared according to the method described in Example 1.

[0054] The lithium iron disulfide battery pre-discharge procedure was as follows: (1) set the first cut-off voltage to 1.48 V, the second cut-off voltage to 1.58 V, the first constant current to 1200 mA, and the second constant current to 400 mA, (2) load the first constant current across the battery to perform constant current discharge, (3) stop discharging when the battery voltage reaches the first cut-off voltage, (4) rest for 8 min, (5) load the second constant current to perform constant current discharge on the battery, (6) stop discharging when the battery voltage reaches the second cut-off voltage, and repeat steps (4), (5), and (6) for 8 times of discharging on the battery, and then end the pre-discharge.

[0055] Example 10

[0056] High-performance lithium manganese dioxide batteries were manufactured and pre-discharged to evaluate the discharge performance under various constant current discharge regimes and storage performance.

[0057] Preparation of positive electrode sheet of lithium-manganese dioxide battery: the positive electrode paste and positive electrode current collector are coated by a coating machine, then baked, rolled, and cut to prepare the positive electrode sheet, wherein the positive electrode paste comprises 90wt% of manganese dioxide, 2wt% of graphite as conductive agent, 4wt% of acetylene black as conductive agent, 1wt% of polyacrylate, and 3wt% of polytetrafluoroethylene as binder.

[0058] Preparation of lithium-manganese dioxide battery: the prepared positive electrode sheet, lithium strip negative electrode sheet, and separator are wound together to prepare an electric core, which is placed in a battery steel shell, injected with electrolyte, and sealed twice, and finally subjected to pre-discharge treatment to prepare a CR123A type high-performance lithium-manganese dioxide battery.

[0059] Pre-discharge step of lithium-manganese dioxide battery: (1) setting the first cut-off voltage to 2.40V, the second cut-off voltage to 2.80V, the first constant current to 1150mA, and the second constant current to 100mA, (2) loading the first constant current on both ends of the battery to perform constant current discharge, (3) stopping discharge when the battery voltage reaches the first cut-off voltage, (4) resting for 5min, (5) loading the second constant current on the battery to perform constant current discharge, (6) stopping discharge when the battery voltage reaches the second cut-off voltage, and repeating steps (4), (5), and (6) to perform 4 times of discharge on the battery, and ending the pre-discharge.

[0060] Example 11

[0061] The positive electrode sheet and lithium-manganese dioxide battery are prepared according to the method of Example 10.

[0062] Pre-discharge step of lithium-manganese dioxide battery: (1) setting the first cut-off voltage to 2.45V, the second cut-off voltage to 2.85V, the first constant current to 1250mA, and the second constant current to 150mA, (2) loading the first constant current on both ends of the battery to perform constant current discharge, (3) stopping discharge when the battery voltage reaches the first cut-off voltage, (4) resting for 6min, (5) loading the second constant current on the battery to perform constant current discharge, (6) stopping discharge when the battery voltage reaches the second cut-off voltage, and repeating steps (4), (5), and (6) to perform 5 times of discharge on the battery, and ending the pre-discharge.

[0063] Example 12

[0064] The positive electrode sheet and lithium-manganese dioxide battery are prepared according to the method of Example 10.

[0065] The lithium-manganese dioxide battery pre-discharge procedure is as follows: (1) set the first cut-off voltage to 2.50 V, the second cut-off voltage to 2.90 V, the first constant current to 1350 mA, and the second constant current to 200 mA, (2) load the first constant current across the battery to perform constant current discharge, (3) stop discharging when the battery voltage reaches the first cut-off voltage, (4) rest for 6 min, (5) load the second constant current to perform constant current discharge on the battery, (6) stop discharging when the battery voltage reaches the second cut-off voltage, and repeat steps (4), (5), and (6) for 6 times of discharging on the battery, and then end the pre-discharge.

[0066] Example 13

[0067] The positive electrode sheet and lithium-manganese dioxide battery are prepared according to the method described in Example 10.

[0068] The lithium-manganese dioxide battery pre-discharge procedure is as follows: (1) set the first cut-off voltage to 2.55 V, the second cut-off voltage to 2.95 V, the first constant current to 1450 mA, and the second constant current to 250 mA, (2) load the first constant current across the battery to perform constant current discharge, (3) stop discharging when the battery voltage reaches the first cut-off voltage, (4) rest for 7 min, (5) load the second constant current to perform constant current discharge on the battery, (6) stop discharging when the battery voltage reaches the second cut-off voltage, and repeat steps (4), (5), and (6) for 7 times of discharging on the battery, and then end the pre-discharge.

[0069] Example 14

[0070] The positive electrode sheet and lithium-manganese dioxide battery are prepared according to the method described in Example 10.

[0071] The lithium-manganese dioxide battery pre-discharge procedure is as follows: (1) set the first cut-off voltage to 2.60 V, the second cut-off voltage to 3.00 V, the first constant current to 1550 mA, and the second constant current to 300 mA, (2) load the first constant current across the battery to perform constant current discharge, (3) stop discharging when the battery voltage reaches the first cut-off voltage, (4) rest for 8 min, (5) load the second constant current to perform constant current discharge on the battery, (6) stop discharging when the battery voltage reaches the second cut-off voltage, and repeat steps (4), (5), and (6) for 8 times of discharging on the battery, and then end the pre-discharge.

[0072] Comparative Example 1

[0073] The positive electrode sheet and lithium-manganese dioxide battery are prepared according to the method described in Example 1.

[0074] Lithium iron disulfide battery pre-discharge procedure: (1) load 800 mA constant current across the battery for 4 min of constant current discharge, rest for 5 min, load 200 mA constant current again for 10 min of constant current discharge, end pre-discharge.

[0075] Comparative Example 2

[0076] Anode sheet and lithium iron disulfide battery were prepared according to the method described in Example 1.

[0077] Lithium iron disulfide battery pre-discharge procedure: (1) load 1000 mA constant current across the battery for 4 min of constant current discharge, rest for 5 min, load 400 mA constant current again for 10 min of constant current discharge, end pre-discharge.

[0078] Comparative Example 3

[0079] Anode sheet and lithium iron disulfide battery were prepared according to the method described in Example 1.

[0080] Lithium iron disulfide battery pre-discharge procedure: (1) load 1200 mA constant current across the battery for 4 min of constant current discharge, rest for 8 min, load 500 mA constant current again for 10 min of constant current discharge, end pre-discharge.

[0081] Comparative Example 4

[0082] Anode sheet and lithium manganese dioxide battery were prepared according to the method described in Example 10.

[0083] Lithium manganese dioxide battery pre-discharge procedure: (1) load 1150 mA constant current across the battery for 2 min of constant current discharge, rest for 5 min, load 100 mA constant current again for 5 min of constant current discharge, end pre-discharge.

[0084] Comparative Example 5

[0085] Anode sheet and lithium manganese dioxide battery were prepared according to the method described in Example 10.

[0086] Lithium manganese dioxide battery pre-discharge procedure: (1) load 1350 mA constant current across the battery for 2 min of constant current discharge, rest for 6 min, load 200 mA constant current again for 5 min of constant current discharge, end pre-discharge.

[0087] Comparative Example 6

[0088] Anode sheet and lithium manganese dioxide battery were prepared according to the method described in Example 10.

[0089] Lithium-manganese dioxide battery pre-discharge step: (1) load 1550 mA constant current on both ends of the battery for 2 min of constant current discharge, stand for 8 min, load 300 mA constant current again for 5 min of constant current discharge, end the pre-discharge.

[0090] Comparative examples 1-3 and examples 1-9 differ in that the pre-discharge method of comparative examples 1-3 is two constant current discharges with a set time, while the pre-discharge method of examples 1-9 is multiple constant current discharges with a set cut-off voltage.

[0091] The batteries prepared by different pre-discharge methods of examples 1-9 and comparative examples 1-3 were subjected to discharge test and storage performance test, and the test results are shown in Tables 1, 2 and 3:

[0092] Table 1: Comparison of discharge capacity at room temperature of FR14505 type lithium iron disulfide battery

[0093]

[0094] Table 2: Comparison of discharge capacity after 70°C high temperature storage of FR14505 type lithium iron disulfide battery

[0095]

[0096]

[0097] Table 3: Comparison of discharge capacity of FR14505 type lithium iron disulfide battery after 100 days of room temperature storage and 70°C high temperature storage

[0098]

[0099] Comparative examples 4-6 and examples 10-14 differ in that the pre-discharge method of comparative examples 4-6 is two constant current discharges with a set time, while the pre-discharge method of examples 10-14 is multiple constant current discharges with a set cut-off voltage.

[0100] The batteries prepared by different pre-discharge methods of examples 4-6 and comparative examples 10-14 were subjected to discharge test and storage performance test, and the test results are shown in Tables 4, 5 and 6:

[0101] Table 4: Comparison of discharge capacity at room temperature of CR123A type lithium-manganese dioxide battery

[0102]

[0103]

[0104] Table 5: Comparison of discharge capacity after 70°C high temperature storage of CR123A type lithium-manganese dioxide battery

[0105]

[0106] Table 6: Discharge capacity comparison of CR123A lithium-manganese dioxide battery stored at room temperature and 70°C for 100 days

[0107]

[0108]

[0109] From the discharge capacity comparison of the examples and comparative examples in Tables 1-6, it is found that the discharge performance and storage performance of the battery pre-discharged by the present application are superior to those of the battery pre-discharged by the conventional pre-discharge method, indicating that the pre-discharge method of the present application can effectively improve the discharge performance and storage performance of cylindrical lithium primary batteries.

[0110] The above-described examples are merely preferred implementation manners of the present application, and do not limit the scope of the present application. Any obvious modification and replacement without departing from the concept of the present application shall fall within the protection scope of the present application.

Claims

1. A method for preparing a high-performance cylindrical lithium primary battery, comprising the following steps: uniformly coating a positive electrode slurry containing active material onto a positive electrode current collector, baking and rolling it, and then slitting it to prepare a positive electrode sheet; then winding the positive electrode sheet, a lithium-ion negative electrode sheet, and a separator together to form a battery cell; placing the battery cell into a battery steel casing, injecting electrolyte and sealing it twice, and finally performing a pre-discharge process; wherein the pre-discharge steps are as follows: (1) Set the first cutoff voltage, the second cutoff voltage, the first constant current, and the second constant current; (2) Apply a first constant current to both ends of the lithium primary battery to perform constant current discharge, and stop discharging when the voltage of the lithium primary battery reaches the first cutoff voltage; (3) After leaving the primary lithium battery for 5-8 minutes, apply a second constant current to perform constant current discharge. Stop discharging when the primary lithium battery voltage reaches the second cutoff voltage. (4) Repeat step (3) 4-8 times of discharge cycle, and then end the pre-discharge treatment; in, The cylindrical lithium primary battery is a lithium iron disulfide battery or a lithium manganese dioxide battery. When the cylindrical primary lithium battery is a lithium iron disulfide battery, the first cutoff voltage for pre-discharge of the lithium iron disulfide battery is 1.35 to 1.50V, and the second cutoff voltage is 1.50 to 1.70V; the first constant current discharge current for pre-discharge of the lithium iron disulfide battery is 500 to 1500mA, and the second constant current discharge current is 100 to 500mA. When the cylindrical primary lithium battery is a lithium manganese dioxide battery, the first cutoff voltage of the lithium manganese dioxide battery before pre-discharge is 2.30 to 2.65V, and the second cutoff voltage is 2.70 to 3.00V; the first constant current discharge current of the lithium manganese dioxide battery before pre-discharge is 500 to 1600mA, and the second constant current discharge current is 100 to 600mA.

2. The method for preparing a high-performance cylindrical lithium primary battery according to claim 1, characterized in that: The pre-discharge amount is at least 4% of the battery capacity.

3. The method for preparing a high-performance cylindrical lithium primary battery according to claim 2, characterized in that: The aforementioned double sealing refers to placing a cylindrical battery containing the battery cell and electrolyte and fitted with a cap into an automatic guide trough, sending it into a first sealing mold to complete the first sealing; after cleaning, placing it into an automatic guide trough and sending it into a second sealing mold to complete the second sealing.

4. The method for preparing a high-performance cylindrical lithium primary battery according to claim 1, characterized in that: The first cutoff voltage of the lithium iron disulfide battery before pre-discharge is 1.38–1.48V, and the second cutoff voltage is 1.52–1.66V; the first constant current discharge current of the lithium iron disulfide battery before pre-discharge is 800–1200mA, and the second constant current discharge current is 200–500mA.

5. The method for preparing a high-performance cylindrical lithium primary battery according to claim 4, characterized in that: The positive electrode of the lithium iron disulfide battery is composed of 70-85 wt% iron disulfide, 4-11 wt% conductive agent, 4-10 wt% binder, and 4-10 wt% positive electrode additive, with the sum of each component reaching 100%; the conductive agent is at least one of graphite and acetylene black; and the binder is at least one of polyvinylidene fluoride and polytetrafluoroethylene.

6. The method for preparing a high-performance cylindrical lithium primary battery according to claim 1, characterized in that: The first cutoff voltage for pre-discharge of the lithium manganese dioxide battery is 2.40–2.60V, and the second cutoff voltage is 2.80–3.00V; the first constant current discharge current for pre-discharge of the lithium manganese dioxide battery is 1150–1550mA, and the second constant current discharge current is 100–300mA.

7. The method for preparing a high-performance cylindrical lithium primary battery according to claim 6, characterized in that: The positive electrode of a lithium manganese dioxide battery is composed of 85-95 wt% manganese dioxide, 2-7 wt% conductive agent, and 3-8 wt% binder; the conductive agent is at least one of graphite and acetylene black; and the binder is at least one of polyacrylate and polytetrafluoroethylene.

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