Formation process of spinel lithium nickel manganese oxide battery

Abstract

The invention relates to a formation process of a spinel lithium nickel manganese oxide battery. The invention relates to a formation process of a spinel lithium nickel manganese oxide battery, which adopts segmented negative pressure formation and comprises the following stages: a first stage: charging to 15% SOC to 20% SOC at a constant current of 0.02 C to 0.05 C, and maintaining the negative pressure to be-30Kpa to-55Kpa; in the second stage, constant-current charging is carried out at 0.05 C to 0.1 C until the SOC reaches 40% SOC to 45% SOC, and the negative voltage is kept at-60 Kpa to-80 Kpa; in the third stage, constant current charging is carried out at 0.05 C to 0.1 C until the SOC reaches 60% SOC to 65% SOC, the voltage ranges from 4.5 V to 4.9 V, and the negative voltage ranges from-30 Kpa to-50 Kpa; and the fourth stage comprises the steps that constant current charging is conducted at 0.05 C to 0.1 C till the SOC is 100%, and the negative pressure is maintained to be-80 Kpa to-100 Kpa till exhausting is complete. According to the formation process disclosed by the invention, the positive electrode material and the electrolyte can fully react in a high SOC state, and the problem that the battery swells in the charge-discharge cycle process of the spinel lithium nickel manganese oxide battery due to insufficient reaction in the formation stage is avoided; and meanwhile, side reactions can be reduced, and produced gas is completely exhausted, so that the capacity and the cycle life of the spinel lithium nickel manganese oxide battery are improved, and the battery performance is improved.

Description

Technical Field

[0001] The invention relates to the technical field of batteries, and in particular to a formation process of a spinel nickel manganese oxide lithium battery. Background Art

[0002] Benefiting from the rapid development of new energy vehicles, the power battery industry has entered a period of rapid growth. Lithium-ion batteries are an ideal high-energy power source in the future due to their superior characteristics such as high energy density, no memory effect, no pollution, and long cycle life. Among them, high-voltage positive electrode materials are currently a hot topic in research. Spinel nickel manganese oxide lithium (LiNi 0.5 Mn 1.5 As an inorganic metal composite oxide, the material has outstanding properties such as a high voltage platform (about 4.7V), a high reversible capacity (146.7mAh / g), and excellent cycle stability at high temperatures.

[0003] In the production process of lithium-ion batteries, the formation process is an extremely important step. This step mainly performs the first charging process on the battery cell to activate the lithium-ion battery. The current understanding is that in the early stage of formation, with the formation of the SEI film, there will be a side reaction of gas production; after the SEI film is formed, the gas production decreases. The formation process usually provides a large negative pressure in the first stage (before the SEI film is fully formed) to discharge the gas produced by the formation; in the subsequent stages, only a small negative pressure needs to be provided to discharge the sporadic gas production. However, this traditional formation process is not suitable for high-voltage systems. Under high-voltage systems, there will be a large number of side reactions between the positive and negative electrode materials and the electrolyte to continuously produce gas, and the traditional formation process cannot completely exhaust the gas production, resulting in black spots on the negative electrode interface, and in the subsequent battery cell cycle process, it will also cause the battery cell to swell, seriously affecting the battery performance and service life. Summary of the invention

[0004] Based on this, it is necessary to provide a formation process for spinel nickel manganese oxide lithium batteries in order to improve battery performance.

[0005] A formation process for a spinel nickel manganese oxide lithium battery adopts segmented negative pressure formation and includes the following stages:

[0006] The first stage includes charging at a constant current of 0.02C to 0.05C to 15% SOC to 20% SOC, maintaining a negative pressure of -30Kpa to -55Kpa;

[0007] The second stage includes charging at a constant current of 0.05C to 0.1C to 40% SOC to 45% SOC, maintaining a negative pressure of -60Kpa to -80Kpa;

[0008] The third stage includes charging at a constant current of 0.05C to 0.1C to 60% SOC to 65% SOC, with a voltage of 4.5V to 4.9V and a negative pressure of -30Kpa to -50Kpa; and

[0009] The fourth stage includes charging at a constant current of 0.05C to 0.1C to 100% SOC, maintaining a negative pressure of -80Kpa to -100Kpa until exhaust is complete.

[0010] The formation process of the spinel nickel manganese oxide battery of the technical solution of the present invention adopts segmented negative pressure formation. On the one hand, the formation process can achieve full reaction between the positive electrode material and the electrolyte under high SOC state until the battery is charged to 100% SOC, thereby avoiding the problem of battery bulging caused by insufficient reaction in the formation stage during the charge and discharge cycle of the spinel nickel manganese oxide battery; on the other hand, the above-mentioned segmented negative pressure formation can reduce the occurrence of side reactions, completely exhaust the gas production, and prevent black spots from being generated on the negative electrode interface, thereby increasing the capacity and cycle life of the spinel nickel manganese oxide battery and improving the battery performance.

[0011] In a feasible implementation, before performing segmented negative pressure formation, the following steps are also included: calibrating the gas production of the battery cell and establishing a curve relationship with the SOC, and determining the current and negative pressure values ​​of the first stage, the second stage, the third stage and the fourth stage based on the curve relationship.

[0012] In a feasible implementation, the operation of calibrating the gas production of the battery cell and establishing a curve relationship with the SOC is: charging at a constant current of 0.05C to 0.1C to 100% SOC, recording the gas production of the battery cell, and obtaining a curve relationship between the gas production of the battery cell and the SOC.

[0013] In a feasible implementation, before performing the segmented negative pressure formation, the following step is also included: the spinel nickel manganese oxide lithium battery after injection is left to stand.

[0014] In a feasible implementation, the standing pressure is a negative pressure, wherein the negative pressure is -10Kpa to -30Kpa; the standing temperature is a normal temperature or a high temperature, wherein the normal temperature is 18°C ​​to 30°C, and the high temperature is 40°C to 50°C; and the standing time is 10min to 30min.

[0015] In a feasible implementation, the first stage further includes the following steps: after constant current charging to 15% SOC ~ 20% SOC, discharging to 1% SOC ~ 5% SOC with a current of 0.05C ~ 0.15C, and the charging and discharging operations are cycled 2 to 5 times.

[0016] In a feasible implementation, the second stage further includes the following steps: after constant current charging to 40% SOC ~ 45% SOC, discharging to 15% SOC ~ 20% SOC with a current of 0.05C ~ 0.15C, and the charging and discharging operations are cycled 2 to 5 times.

[0017] In a feasible implementation, an aging process is also included after the fourth stage.

[0018] In a feasible implementation, the aging treatment is performed by standing for 10 min to 30 min under a negative pressure of -20 Kpa to -40 Kpa.

[0019] In a feasible implementation, the temperature of the first stage, the second stage, the third stage and the fourth stage is 5°C to 45°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a flow chart of a formation process of a spinel nickel manganese oxide lithium battery according to one embodiment of the present invention;

[0021] Figure 2 This is a calibration diagram of gas production and SOC of a cell in a formation process of a spinel nickel-manganese-oxide lithium battery according to Example 1 of the present invention;

[0022] Figure 3 The black spots on the interface of the spinel nickel manganese oxide lithium battery of Example 1 of the present invention;

[0023] Figure 4 This is the interface black spot situation of the spinel nickel manganese oxide lithium battery of comparative example 1 of the present invention;

[0024] Figure 5 The graph is a cycle life curve of the spinel nickel manganese oxide lithium battery of Example 1, Example 2 and Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0025] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0027] In the present invention, SOC, or State of Charge, refers to the charging state of the battery, which can be referred to as the state of charge, that is, the remaining power. It represents the ratio of the remaining available power to the power in the fully charged state after the battery has been used or stored for a period of time. This ratio is usually expressed as a hexadecimal percentage, with a value range of 00 to 100.

[0028] See also Figure 1 The formation process of the spinel nickel manganese oxide lithium battery according to one embodiment of the present invention adopts segmented negative pressure formation, including the following stages:

[0029] S10, the first stage, includes charging at a constant current of 0.02C to 0.05C to 15% SOC to 20% SOC, maintaining a negative pressure of -30Kpa to -55Kpa.

[0030] During the first stage of formation, the gas production volume increases continuously, and the gas production rate increases continuously and at a relatively fast rate. Setting the negative pressure to -30Kpa to -55Kpa can discharge part of the gas, and a dense and stable SEI film is basically formed after the first stage. It should be noted that the negative pressure is maintained at -30Kpa to -55Kpa during constant current charging.

[0031] Furthermore, the constant current charging current may be but is not limited to 0.02C, 0.03C, 0.04C or 0.05C, the state of charge SOC may be but is not limited to 15%, 16%, 17%, 18%, 19% or 20%, and the negative pressure may be but is not limited to -30Kpa, -35Kpa, -40Kpa, -45Kpa, -50Kpa or -55Kpa.

[0032] In a feasible implementation, the first stage also includes the following steps: after constant current charging to 15% SOC ~ 20% SOC, discharge to 1% SOC ~ 5% SOC at a current of 0.05C ~ 0.15C, and cycle the charging and discharging operation 2 to 5 times. This is conducive to SEI film formation and exhaust, and improves the stability of the battery cell. It is understandable that the number of operation cycles of charging and discharging in the first stage is not limited to this, and can also be set according to actual conditions.

[0033] S20, the second stage, includes charging at a constant current of 0.05C to 0.1C to 40% SOC to 45% SOC, maintaining a negative pressure of -60Kpa to -80Kpa.

[0034] During the second stage of formation, the gas production continues to increase. Due to the increase in current density, the gas production rate continues to increase and the rate is relatively fast. Increasing the negative pressure value can continue to discharge some gas. It should be noted that the negative pressure is maintained at -60Kpa to -80Kpa during constant current charging.

[0035] Furthermore, the constant current charging current may be but is not limited to 0.05C, 0.06C, 0.07C, 0.08C, 0.09C or 0.1C, the state of charge SOC may be but is not limited to 40%, 41%, 42%, 43%, 44% or 45%, and the negative pressure may be but is not limited to -60Kpa, -70Kpa or -80Kpa.

[0036] In a feasible implementation, the second stage also includes the following steps: after constant current charging to 40% SOC ~ 45% SOC, discharge to 15% SOC ~ 20% SOC at a current of 0.05C ~ 0.15C, and the charging and discharging operation cycle is 2 to 5 times. This is conducive to completely discharging the gas in the fastest gas production stage. Further, the discharge current can be but not limited to 0.05C, 0.1C or 0.15C, and the charging and discharging operation cycle can be but not limited to 2 times, 3 times, 4 times or 5 times. It can be understood that the number of charging and discharging operation cycles in the second stage is not limited to this, and can also be set according to actual conditions.

[0037] S30, the third stage, includes charging at a constant current of 0.05C to 0.1C to 60% SOC to 65% SOC, and the voltage is 4.5V to 4.9V, and the negative pressure is maintained at -30Kpa to -50Kpa.

[0038] In the third stage, under the action of SEI, the gas production is small. Using a larger current to charge can reduce the charging time and improve the charging efficiency. At this time, a lower negative pressure value can be maintained. It should be noted that the negative pressure is maintained at -30Kpa to -50Kpa during constant current charging.

[0039] Furthermore, the constant current charging current may be but is not limited to 0.05C, 0.06C, 0.07C, 0.08C, 0.09C or 0.1C, the state of charge SOC may be but is not limited to 60%, 61%, 62%, 63%, 64% or 65%, the voltage may be but is not limited to 4.5V, 4.6V, 4.7V, 4.8V or 4.9V, and the negative pressure may be but is not limited to -30Kpa, -40Kpa or -50Kpa.

[0040] S40, the fourth stage, includes charging at a constant current of 0.05C to 0.1C to 100% SOC, maintaining a negative pressure of -80Kpa to -100Kpa, until exhaust is complete.

[0041] The gas production in the fourth stage is relatively large, and the gas production rate is constantly increasing. At this time, the gas is exhausted without extracting the electrolyte, and the fourth negative pressure is set to -80Kpa~-100Kpa until the gas is completely exhausted. It should be noted that the negative pressure is maintained at -80Kpa~-100Kpa during constant current charging.

[0042] Furthermore, the current of the constant current charging may be, but is not limited to, 0.05C, 0.06C, 0.07C, 0.08C, 0.09C or 0.1C, and the negative pressure may be, but is not limited to, -80Kpa, -90Kpa or -100Kpa.

[0043] In a feasible implementation, after the fourth stage, an aging treatment is also included. The aging treatment process is to let the battery stand still, the purpose of which is to make the electrolyte infiltrate better and facilitate the stability of battery performance.

[0044] In a feasible implementation, the aging treatment is performed by standing for 10 to 30 minutes under a negative pressure of -20Kpa to -40Kpa. Further, the negative pressure may be, but not limited to, -20Kpa, -30Kpa or -40Kpa, and the standing time may be, but not limited to, 10 minutes, 20 minutes or 30 minutes.

[0045] In a feasible implementation, before performing segmented negative pressure formation, the following steps are also included: calibrate the gas production of the battery cell and establish a curve relationship with the SOC, and determine the current and negative pressure values ​​of the first stage, the second stage, the third stage, and the fourth stage based on the curve relationship. Specifically, the gas production in the first stage is small, so the negative pressure value and the current are set to be relatively small; the gas production rate in the second stage is fast, so the negative pressure value and the current are set to be slightly larger than the first stage; the gas production in the third stage is small, in order to charge quickly and save time, the current is increased, and the negative pressure value is small at this time; the gas production in the fourth stage is large, the gas production rate continues to rise, the negative pressure value is set to a relatively large peak value, and the current can be equivalent to or slightly smaller than the previous stage, in order to ensure that the electrolyte is not exhausted.

[0046] In a feasible implementation, the operation of calibrating the gas production of the battery cell and establishing a curve relationship with the SOC is: charging at a constant current of 0.05C to 0.1C to 100% SOC, recording the gas production of the battery cell, and obtaining a curve relationship between the gas production of the battery cell and the SOC. In a feasible implementation, before performing the segmented negative pressure formation, the following steps are also included: the spinel nickel manganese oxide lithium battery after injection is allowed to stand.

[0047] In a feasible implementation, the static pressure is negative pressure, wherein the negative pressure is -10Kpa to -30Kpa; the static temperature is room temperature or high temperature, wherein the room temperature is 18℃ to 30℃, and the high temperature is 40℃ to 50℃; the static time is 10min to 30min. Furthermore, the static pressure is negative pressure, which has the advantage of timely removing the generated gas, ensuring the stability and consistency of the SEI film, and reducing the loss of the electrolyte; the static temperature is preferably high temperature, which has the advantage of accelerating the diffusion of the electrolyte, allowing the positive and negative active materials and the electrolyte to be fully infiltrated, which helps the electrolyte to better penetrate into the electrode material and ensure the performance and stability of the battery. It should be noted that the static temperature can also be any value between room temperature and high temperature.

[0048] In a feasible implementation, the temperature of the first stage, the second stage, the third stage and the fourth stage is 5°C to 45°C.

[0049] Furthermore, after the formation is completed, the formed battery can be welded, divided into different capacities, self-discharged and screened, etc. The battery can also be tested for cycle charge and discharge performance, under the condition of negative pressure value of -20Kpa to -60Kpa, the current is set to 0.33C to 0.5C, and discharged to 30% SOC to 60% SOC.

[0050] In a feasible implementation, the spinel nickel manganese oxide lithium battery includes a positive electrode material, the positive electrode material includes spinel nickel manganese oxide lithium (LiNi 0.5 Mn 1.5 O4). Spinel nickel lithium manganese oxide (LiNi 0.5 Mn 1.5 As an inorganic metal composite oxide, the material has outstanding properties such as a high voltage platform (about 4.7V), a high reversible capacity (up to 146.7mAh / g), and excellent cycle stability at high temperatures.

[0051] The formation process of the spinel nickel manganese oxide battery of the technical solution of the present invention adopts segmented negative pressure formation. On the one hand, the formation process can achieve full reaction between the positive electrode material and the electrolyte under high SOC state until the battery is charged to 100% SOC, thereby avoiding the problem of battery bulging caused by insufficient reaction in the formation stage during the charge and discharge cycle of the spinel nickel manganese oxide battery; on the other hand, the above-mentioned segmented negative pressure formation can reduce the occurrence of side reactions, completely exhaust the gas production, and prevent black spots from being generated on the negative electrode interface, thereby increasing the capacity and cycle life of the spinel nickel manganese oxide battery and improving the battery performance.

[0052] With reference to the above implementation contents, in order to make the technical solution of the present invention more specific, clear and easy to understand, the technical solution of the present invention is now exemplified. However, it should be noted that the contents to be protected by the present invention are not limited to the following embodiments.

[0053] Example 1

[0054] Example 1 provides a formation process for a spinel nickel manganese oxide lithium battery, wherein a nickel manganese oxide lithium soft pack battery is used in this embodiment; the battery model is 9114897, the capacity is 12Ah, and it is charged to 4.9V with a constant current of 0.75A. The battery composition is as follows:

[0055] Positive electrode: 95% LNMO + 2% super-P + 3% PVDF;

[0056] Negative electrode: 95% graphite + 2% super-P + 3% (CMC + SBR);

[0057] Electrolyte: 1MLiPF6+1:1EC:DEC;

[0058] The relationship curve between the gas production and SOC calibrated in this embodiment is as follows: Figure 2 As shown;

[0059] Step 1. Establish the relationship between SOC and gas production;

[0060] The battery cell that has been filled and left to stand is charged at a constant current of 0.05C to 100% SOC (i.e. fully charged, 4.9V). At the same time, the gas production of the battery cell is recorded using the buoyancy method or the drainage method. The charging capacity and gas production are processed to obtain the gas production V-SOC relationship.

[0061] Step 2. Based on the relationship obtained in step 1, determine the first endpoint, the second endpoint and the third endpoint.

[0062] The test methods for gas production are: buoyancy method; Figure 2 It can be seen that the gas production is divided into the following four stages:

[0063] Among them, in the first stage, when the battery is below 20% SOC, the formation rate is slow; in the second stage, when the battery is at 20-40% SOC, the gas production rate is the fastest compared with other stages; in the third stage, when the battery is at 40-60% SOC, the gas production rate slows down significantly; in the fourth stage, when the battery is at 60-100% SOC, the gas production rate is also in a rapid upward trend.

[0064] The formation process of the spinel nickel manganese oxide lithium battery of this embodiment includes:

[0065] 1) Standing: In order to reduce the mass of electrolyte extracted from the battery during formation, let it stand for 20 minutes before formation, with a negative pressure of -20Kpa;

[0066] 2) Segmented negative pressure formation:

[0067] The first stage: charge to 20% SOC at 0.05C constant current, maintain negative pressure value -40Kpa; then discharge to 3% SOC at 0.05C, and cycle the charge and discharge operation 3 times;

[0068] The second stage: charge to 40% SOC at 0.07C constant current, maintain negative pressure value -70Kpa; then discharge to 20% SOC at 0.1C, and cycle charge and discharge for 3 times;

[0069] The third stage: charging at 0.1C constant current to 60% SOC, maintaining a negative pressure of -50Kpa;

[0070] Stage 4: Maintain negative pressure at -80Kpa, charge to 4.9V at 0.08C constant current, then charge at constant voltage until the current becomes 0.05C, which helps to ensure that the battery can be fully charged while avoiding overcharging, thereby stabilizing battery performance. At this time, charge to 100% SOC;

[0071] 3) Aging: Let stand for 10 minutes, maintain negative pressure value -20Kpa;

[0072] 4) Discharge: Discharge at a constant current of 0.33C for 1.5h (50% SOC) to complete the formation of the spinel nickel manganese oxide lithium battery;

[0073] 5) The formed batteries will then be subjected to welding, capacity division, self-discharge screening, etc.

[0074] Example 2

[0075] Example 2 provides a formation process for a spinel nickel manganese oxide battery, which is the same as the spinel nickel manganese oxide battery and the test method for formation gas production used in Example 1. The only difference from the formation process of Example 1 is that no charging and discharging cycle operation is performed in the first and second stages of the segmented negative pressure formation, and the parameters such as the charging current, charging state and negative pressure in each stage of the segmented negative pressure formation are different. Please see Table 1 for details.

[0076] Table 1 Parameter values ​​of each stage of the segmented negative pressure formation of Example 2

[0077]

[0078] Comparative Example 1

[0079] Comparative Example 1 provides a formation process of a spinel nickel manganese oxide lithium battery, using the same nickel manganese oxide lithium soft pack battery as Example 1; the formation process is as follows:

[0080] 1) Standing: Standing for 20 minutes before formation, no negative pressure value;

[0081] 2) Segmented negative pressure formation:

[0082] The first stage: negative pressure value -40Kpa, current 0.05C, constant current charging to 5% SOC;

[0083] The second stage: negative pressure value -60Kpa, current 0.1C, constant current charging to 20% SOC;

[0084] The third stage: negative pressure value -60Kpa, current 0.1C, constant current charging to 60% SOC;

[0085] The fourth stage: negative pressure value -60Kpa, current 0.33C, constant current charging to 4.9V, and then constant voltage charging until the current becomes 0.05C;

[0086] 3) Aging: let stand for 10 minutes, no negative pressure value;

[0087] 4) Discharge: Discharge at a constant current of 0.33C for 1.5h (50% SOC) to complete the formation of the spinel nickel manganese oxide lithium battery;

[0088] 5) The formed batteries will then be subjected to welding, capacity division, self-discharge screening, etc.

[0089] Performance Testing:

[0090] The spinel nickel manganese oxide lithium batteries obtained in Examples 1 to 2 and Comparative Example 1 were subjected to cycle tests. The temperature conditions and test methods were as follows. The performance results are shown in Table 2. The black spots on the battery interface of Example 1 and Comparative Example 1 are as follows: Figure 3 and 4 As shown; the cycle life curve of the spinel nickel manganese oxide lithium battery of Examples 1 to 2 and Comparative Example 1 is as shown Figure 5 shown.

[0091] Temperature: 25℃±2℃

[0092] ① Charge at 1C to the final voltage, cut-off current 0.05C, and let stand for 30 minutes;

[0093] ②Discharge at 1C to the final discharge voltage, record the discharge capacity, and let stand for 30 minutes;

[0094] Cycle ①~②;

[0095] Cycle performance:

[0096] Table 2 Battery cycle performance of the embodiments and comparative examples

[0097] Performance parameters Liquid retention coefficient DCIR Interface black spots 500 cycles Example 1 3.35 0.96 none 94.61 Example 2 3.36 0.92 Small amount 93.73 Comparative Example 1 3.18 1.25 Large 91.27

[0098] It can be seen from Table 2 that the liquid retention coefficient, DCIR and 500 cycle performance of the spinel nickel manganese oxide lithium battery of Examples 1 to 2 of the present invention are better than the corresponding performance of the spinel nickel manganese oxide lithium battery of Comparative Example 1; Figure 3 and Figure 4 It can be seen that there are no black spots on the battery interface of Example 1 of the present invention, while there are a large number of black spots on the battery interface of Comparative Example 1. Figure 5 It can be seen that the cycle life of the spinel nickel manganese oxide battery of Example 1 is significantly better than the cycle life of the spinel nickel manganese oxide battery of Example 2 and Comparative Example 1. The above shows that the formation process of the spinel nickel manganese oxide battery of the present invention can achieve full reaction between the positive electrode material and the electrolyte under high SOC state, reduce the occurrence of side reactions, and completely exhaust the gas production. At the same time, it can avoid battery bulging and black spots on the negative electrode interface, increase the capacity and cycle life of the spinel nickel manganese oxide battery, and enhance the battery performance.

[0099] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0100] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A formation process for a spinel nickel manganese oxide lithium battery, characterized in that: Adopt segmented negative pressure forming, The following phases are included: The first stage includes charging at a constant current of 0.02C to 0.05C to 15% SOC to 20% SOC, maintaining a negative pressure of -30Kpa to -55Kpa; The second stage includes charging at a constant current of 0.05C to 0.1C to 40% SOC to 45% SOC, maintaining a negative pressure of -60Kpa to -80Kpa; The third stage includes charging at a constant current of 0.05C to 0.1C to 60% SOC to 65% SOC, with a voltage of 4.5V to 4.9V and a negative pressure of -30Kpa to -50Kpa; and The fourth stage includes charging at a constant current of 0.05C to 0.1C to 100% SOC, maintaining a negative pressure of -80Kpa to -100Kpa until exhaust is complete.

2. The formation process of the spinel nickel manganese oxide lithium battery according to claim 1, characterized in that: Before performing segmented negative pressure formation, the following steps are also included: calibrating the gas production of the battery cell and establishing a curve relationship with the SOC, and determining the current and negative pressure values ​​of the first stage, the second stage, the third stage and the fourth stage based on the curve relationship.

3. The formation process of the spinel nickel manganese oxide lithium battery according to claim 2, characterized in that: The operation of calibrating the gas production of the battery cell and establishing a curve relationship with the SOC is: charging at a constant current of 0.05C to 0.1C to 100% SOC, recording the gas production of the battery cell, and obtaining a curve relationship between the gas production of the battery cell and the SOC.

4. The formation process of the spinel nickel manganese oxide lithium battery according to claim 1, characterized in that: Before performing the segmented negative pressure formation, the method further includes the following steps: allowing the injected spinel nickel manganese oxide lithium battery to stand.

5. The formation process of the spinel nickel manganese oxide lithium battery according to claim 4, characterized in that: The static pressure is negative pressure, wherein the negative pressure is -10Kpa to -30Kpa; the static temperature is normal temperature or high temperature, wherein the normal temperature is 18°C ​​to 30°C, and the high temperature is 40°C to 50°C; the static time is 10min to 30min.

6. The formation process of the spinel nickel manganese oxide lithium battery according to claim 1, characterized in that: The first stage also includes the following steps: after constant current charging to 15% SOC-20% SOC, discharging to 1% SOC-5% SOC at a current of 0.05C-0.15C, the charging and discharging operations are cycled 2-5 times.

7. The formation process of spinel nickel manganese oxide lithium battery according to claim 1, characterized in that: The second stage further comprises the following steps: after constant current charging to 40% SOC-45% SOC, discharging to 15% SOC-20% SOC at a current of 0.05C-0.15C, the charging and discharging operations are cycled 2-5 times.

8. The formation process of spinel nickel manganese oxide lithium battery according to claim 1, characterized in that: After the fourth stage, an aging process is also included.

9. The formation process of the spinel nickel manganese oxide lithium battery according to claim 8, characterized in that: The operation of the aging treatment is: standing for 10 minutes to 30 minutes under a negative pressure condition of -20Kpa to -40Kpa.

10. The formation process of a spinel nickel manganese oxide lithium battery according to any one of claims 1 to 9, characterized in that: The temperature of the first stage, the second stage, the third stage and the fourth stage is 5°C to 45°C.

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