Battery cell formation method and device, battery cell and electronic equipment

Abstract

The invention is applicable to the field of battery cell manufacturing, and provides a battery cell formation method and device, a battery cell and electronic equipment.The method comprises the steps that in a first set pressure environment, a semi-finished battery cell to be formed is charged according to first set current until the charging voltage reaches first cut-off voltage; under a second set pressure environment, charging the semi-finished battery cell according to a second set current until the charging voltage reaches a second cut-off voltage; the second set pressure is greater than the first set pressure, the second set current is greater than the first set current, and the second cut-off voltage is greater than the first cut-off voltage; carrying out vacuumizing treatment and air bag cutting treatment on the semi-finished battery cell; charging the semi-finished battery cell until the charging voltage reaches a third cut-off voltage; and packaging the semi-finished battery cell to obtain a finished battery cell. The problem that a large amount of gas exists in a finished battery cell can be solved.

Description

Technical Field

[0001] The present application relates to the field of battery cell manufacturing, and in particular to a battery cell formation method, device, battery cell and electronic equipment. Background Art

[0002] Battery cell formation is an important step in battery cell manufacturing. During the formation process, a layer of solid electrolyte interface membrane (SEI membrane) will be formed on the surface of the semi-finished battery cell. With the formation of the SEI membrane, a certain amount of gas will be generated in the semi-finished battery cell. After the formation based on the existing battery cell formation method, a large amount of gas remains inside the finished battery cell obtained by encapsulation, and the battery cell is prone to displacement or deformation, causing damage to the corners of the battery cell and leakage, which not only poses a safety hazard, but also affects the service life of the battery cell. Therefore, it is necessary to solve the problem of a large amount of gas inside the finished battery cell caused by battery cell formation. Summary of the invention

[0003] The embodiments of the present application provide a battery cell formation method, device, battery cell and electronic device to solve the problem of a large amount of gas inside a finished battery cell caused by battery cell formation in the prior art.

[0004] A first aspect of an embodiment of the present application provides a battery cell formation method, comprising:

[0005] Under a first set pressure environment, the semi-finished battery cell to be formed is charged according to a first set current until the charging voltage reaches a first cut-off voltage; the semi-finished battery cell corresponding to the first cut-off voltage has an SEI film that meets the first set requirements;

[0006] Under a second set pressure environment, the semi-finished battery cell is charged according to a second set current until the charging voltage reaches a second cut-off voltage; the second set pressure is greater than the first set pressure, the second set current is greater than the first set current, the second cut-off voltage is greater than the first cut-off voltage, and the semi-finished battery cell corresponding to the second cut-off voltage has an SEI film that meets the second set requirements;

[0007] Performing vacuum treatment and air bag cutting treatment on the semi-finished battery cell;

[0008] Charging the semi-finished battery cell until the charging voltage reaches a third cut-off voltage; the third cut-off voltage is greater than the second cut-off voltage;

[0009] The semi-finished battery cells are packaged to obtain finished battery cells.

[0010] A second aspect of an embodiment of the present application provides a battery cell formation device, comprising:

[0011] A first charging module is used to charge the semi-finished battery cell to be formed according to a first set current under a first set pressure environment until the charging voltage reaches a first cut-off voltage; the semi-finished battery cell corresponding to the first cut-off voltage has an SEI film that meets the first set requirements;

[0012] a second charging module, used for charging the semi-finished battery cell according to a second set current under a second set pressure environment until the charging voltage reaches a second cut-off voltage; the second set pressure is greater than the first set pressure, the second set current is greater than the first set current, the second cut-off voltage is greater than the first cut-off voltage, and the semi-finished battery cell corresponding to the second cut-off voltage has an SEI film that meets the second set requirements;

[0013] A degassing module, used for performing a vacuum treatment and a gas bag cutting treatment on the semi-finished battery cell;

[0014] a third charging module, used to charge the semi-finished battery cell until the charging voltage reaches a third cut-off voltage; the third cut-off voltage is greater than the second cut-off voltage;

[0015] The packaging module is used to package the semi-finished battery cells to obtain finished battery cells.

[0016] A third aspect of an embodiment of the present application provides a battery cell, which is manufactured based on the steps of the method described in the first aspect.

[0017] The fourth aspect of an embodiment of the present application provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method described in the first aspect when executing the computer program.

[0018] A fifth aspect of the embodiments of the present application provides a computer program product. When the computer program product is run on a terminal, the terminal executes the steps of the method described in the first aspect.

[0019] A sixth aspect of an embodiment of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method described in the first aspect are implemented.

[0020] As can be seen from the above, the present application is divided into three charging stages, each stage corresponds to a specific cut-off voltage, and the semi-finished battery cells are charged and formed in stages. In the first two charging stages, the pressure and current are controlled, the semi-finished battery cells are placed in different pressure environments, and the semi-finished battery cells are charged with different set currents. Among them, the first charging stage uses a smaller pressure and current to reduce the output of gas, and the second charging stage increases the pressure and current, discharges the gas, and promotes the stability of the SEI film to avoid the unstable SEI film from being destroyed, resulting in increased gas production. After the second charging stage, vacuum treatment and gas bag cutting treatment are added to discharge the retained gas. Subsequently, the finished battery cell can be obtained by the final charging stage and packaging. The amount of gas in the finished battery cell is greatly reduced, which solves the problem of a large amount of gas in the finished battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 It is a flow chart of a battery cell formation method provided in an embodiment of the present application;

[0023] Figure 2 This is an interface comparison diagram of a finished battery cell provided in an embodiment of the present application;

[0024] Figure 3 It is a structural diagram of a battery cell formation device provided in an embodiment of the present application;

[0025] Figure 4 It is a structural diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0026] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0027] It should be understood that when used in this specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0028] It should also be understood that the terms used in this application specification are only for the purpose of describing specific embodiments and are not intended to limit the application. As used in this application specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0029] It should be further understood that the term “and / or” used in the specification and appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0030] As used in this specification and the appended claims, the term "if" may be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrases "if it is determined" or "if [described condition or event] is detected" may be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.

[0031] In a specific implementation, the terminal described in the embodiments of the present application includes, but is not limited to, other portable devices such as mobile phones, laptop computers, or tablet computers with touch-sensitive surfaces (e.g., touch screen displays and / or touch pads). It should also be understood that in some embodiments, the device is not a portable communication device, but a desktop computer with a touch-sensitive surface (e.g., touch screen displays and / or touch pads).

[0032] In the following discussion, a terminal including a display and a touch-sensitive surface is described. However, it should be understood that the terminal may include one or more other physical user interface devices such as a physical keyboard, mouse and / or joystick.

[0033] The terminal supports various applications, such as one or more of the following: a drawing application, a presentation application, a word processing application, a website creation application, a disk burning application, a spreadsheet application, a game application, a telephone application, a video conferencing application, an email application, an instant messaging application, a workout support application, a photo management application, a digital camera application, a digital camcorder application, a web browsing application, a digital music player application, and / or a digital video player application.

[0034] Various applications that can be executed on the terminal can use at least one common physical user interface device such as a touch-sensitive surface. One or more functions of the touch-sensitive surface and corresponding information displayed on the terminal can be adjusted and / or changed between applications and / or within corresponding applications. In this way, the common physical architecture of the terminal (e.g., the touch-sensitive surface) can support various applications with user interfaces that are intuitive and transparent to the user.

[0035] It should be understood that the size of the serial numbers of the steps in this embodiment does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present application.

[0036] In order to illustrate the technical solution described in this application, a specific embodiment is provided below for illustration.

[0037] See also Figure 1 , Figure 1 1 is a flow chart of a battery cell formation method provided in an embodiment of the present application. Figure 1 As shown, a battery cell formation method comprises the following steps:

[0038] Step 101 , charging the semi-finished battery cell to be formed according to a first set current under a first set pressure environment until the charging voltage reaches a first cut-off voltage, and the semi-finished battery cell corresponding to the first cut-off voltage has an SEI film that meets the first set requirement.

[0039] The semi-finished battery cell to be formed is a pre-processed semi-finished battery cell. That is, the semi-finished battery cell to be formed is charged according to the first set current under the first set pressure environment until the charging voltage reaches the first cut-off voltage, and further includes: the semi-finished battery cell with liquid injection is left to stand for a preset time to obtain the semi-finished battery cell to be formed.

[0040] Electrolyte is injected into the interior of the semi-finished battery cell that has not been injected with liquid to obtain the semi-finished battery cell that has been injected with liquid. During the injection process, due to the flow of the electrolyte and the complexity of the internal structure of the semi-finished battery cell, some tiny bubbles may be introduced. The presence of bubbles may affect the uniform distribution of the electrolyte and even cause the performance of the battery cell to decline. By standing, these bubbles have enough time to rise and discharge in the electrolyte, thereby reducing the number of bubbles inside the semi-finished battery cell, that is, reducing the amount of gas in the semi-finished battery cell before formation. By standing, it is ensured that the electrolyte can fully penetrate into the interior of the semi-finished battery cell, improve the uniformity of the electrolyte distribution, ensure that the internal wetting interface of the pole piece is good, and the improvement of the wetting effect also helps to reduce local overheating and abnormal gas production caused by poor wetting. In addition, uniform electrolyte distribution is also very helpful for the formation of a uniform and stable SEI film during the formation process.

[0041] The preset time is determined according to factors such as the properties of the electrolyte, the internal structure of the battery cell, and the amount of liquid injected. According to the preset time, the semi-finished battery cell with liquid injected is left to stand to obtain the semi-finished battery cell to be formed.

[0042] In some embodiments, the preset time length is 4-8 hours, or the preset time length is 24-48 hours.

[0043] After the rest period is completed, the battery cell formation stage officially begins. Battery cell formation is a very important part of the battery cell production process. It is the process of charging the semi-finished battery cell for the first time after liquid injection.

[0044] For semi-finished cells, such as lithium-containing semi-finished cells, formation can activate the active substances in the semi-finished cells and activate the semi-finished cells. During charging, the lithium salt reacts with the electrolyte. At the same time, an SEI film is generated on the negative electrode surface of the semi-finished cells. The SEI film can prevent the further occurrence of side reactions, thereby avoiding the gas generated by the damage of the solvent molecules to the electrode materials, and significantly reducing the amount of gas generated by the side reactions in the initial activation stage of the cells. In addition, the SEI film prevents the further occurrence of side reactions, reduces the loss of active lithium in the semi-finished cells, avoids the damage of the solvent molecules to the electrode materials, and ensures the cycle performance of the cells. That is, the SEI film, a protective film, ensures the service life of the finished cells.

[0045] In this application, formation involves three charging stages. Before formation, the temperature, current, cut-off voltage, pressure and other data of each charging stage are pre-set.

[0046] In some embodiments, the formation temperature during the formation process is set to 25°C.

[0047] Under the first set pressure environment, the semi-finished battery cell to be formed is charged with a first set current until the charging voltage reaches a first cut-off voltage, that is, the charging operation of the first charging stage is completed.

[0048] The first charging stage is the formation period of SEI film, which will produce a lot of gas. Do not use too much pressure, otherwise it will affect the flow and infiltration of the electrolyte and the service life of the finished battery. At the same time, use a small current to charge to improve the density of the SEI film, reduce gas production, and further increase the service life of the finished battery.

[0049] In some embodiments, the first set pressure is 0.3-2 MPa, usually in the range of 0.3-1 MPa.

[0050] In some embodiments, the value range of the first set current is a current value range corresponding to 0.15-0.25C.

[0051] The first charging stage is a period of formation of the SEI film, and the first cut-off voltage is determined based on the first setting requirement.

[0052] Accordingly, after the first charging stage is completed, a semi-finished battery cell is obtained whose SEI film meets the first set requirement and whose charging voltage is the first cut-off voltage. That is, at this time, the SEI film formed in the semi-finished battery cell has a compactness of arrangement of internal particles or molecules, a barrier capability of the SEI film to external substances, and stability and durability during the charging and discharging process, etc., which all meet the first set requirement.

[0053] The battery state of charge (SOC) is used to represent the cut-off voltage.

[0054] In some embodiments, the value range of the first cut-off voltage is a voltage value range corresponding to 1%-2% SOC.

[0055] In the first charging stage, i.e. the formation period of SEI film, charging with a small current makes it easier for single electron reaction to occur, making the SEI film structure more compact. The compact SEI film can more effectively block the side reaction between the load ions and the electrolyte, reducing the probability of side reaction, thereby reducing the amount of gas produced. Charging with a small current means that the charging time is relatively extended, which also provides some time for electrolyte infiltration, helping the electrolyte to more fully penetrate into the battery cell, improving the infiltration effect, and reducing the effects of local overheating and gas generation caused by uneven distribution of electrolyte.

[0056] Similarly, setting a lower ambient pressure can prevent the pressure from affecting the flow of the electrolyte, reduce side reactions, and reduce gas production.

[0057] Step 102, under a second set pressure environment, charging the semi-finished battery cell according to a second set current until the charging voltage reaches a second cut-off voltage; the second set pressure is greater than the first set pressure, the second set current is greater than the first set current, the second cut-off voltage is greater than the first cut-off voltage, and the semi-finished battery cell corresponding to the second cut-off voltage has an SEI film that meets the second set requirements.

[0058] The second charging stage is a stabilization period of the SEI film, which is used to maintain and stabilize the SEI film, and the SEI film may be regenerated in this stage. The cut-off voltage of the second charging stage is determined according to the second setting requirement.

[0059] In some embodiments, the second cut-off voltage has a value range of a voltage value corresponding to 8%-10% SOC.

[0060] The second cut-off voltage is the voltage value corresponding to the sum of the charging power of the first charging stage and the charging power of the second charging stage. For example, if the actual charging power of the first charging stage is 1% SOC and the charging power of the second charging stage is 9% SOC, the second cut-off voltage is the voltage value corresponding to 10% SOC.

[0061] After the first charging stage, the SEI film is basically formed and enters the second charging stage. The charging current can be appropriately increased to promote the stability of the SEI film. At the same time, a higher pressure can be used to generate gas for charging.

[0062] In some embodiments, the second set current has a value range of 0.45-0.55 C. A larger current can speed up the formation speed of the second charging stage, save time, and improve efficiency.

[0063] In some embodiments, the second set pressure is greater than the first set pressure. For example, the first set pressure is 0.5 MPa, and the second set pressure is 1.5 MPa; the first set pressure is 1 MPa, and the second set pressure is 2 MPa; the first set pressure is 2 MPa, and the second set pressure is 3 MPa; and so on.

[0064] It should be noted that the increased pressure in the second charging stage will lead to more side reactions. Therefore, it is necessary to control the amount of electrolyte in the semi-finished battery cell. The electrolyte should not be too much to avoid excessive by-products and increased gas production.

[0065] Under the second set pressure environment, the semi-finished battery cell is charged with the second set current until the charging voltage reaches the second cut-off voltage. At this time, the semi-finished battery cell with the SEI film meeting the second set requirements and the charging voltage being the second cut-off voltage is obtained. The SEI film in the semi-finished battery cell has the tightness of the arrangement of internal particles or molecules, the SEI film's ability to block external substances, and the stability and durability during the charging and discharging process, etc., all meet the second set requirements. The second set requirements are higher than the first set requirements. In the second charging stage, part of the gas is discharged and the SEI film is maintained, which is beneficial to the improvement of the service life of the battery cell.

[0066] Step 103, vacuuming and air bag cutting the semi-finished battery cell.

[0067] After the second charging stage, the SEI film has been fully formed and less gas is generated. At this time, the gas that was not completely discharged in the second charging stage can be processed intensively.

[0068] Therefore, after the charging voltage reaches the second cut-off voltage, a vacuum pumping device is used to perform a vacuum treatment on the semi-finished battery cell to extract the gas inside the semi-finished battery cell. At the same time, an air bag cutting device is used to perform an air bag cutting treatment on the semi-finished battery cell to remove the air bags of the semi-finished battery cell and reduce the existing gas inside the semi-finished battery cell.

[0069] In some embodiments, when cutting the air bags of the semi-finished battery cells, air bags of a preset capacity are cut off.

[0070] The preset capacity is determined by calculation and testing to ensure that the remaining air pocket space meets the gas generation requirements of the battery cell during the subsequent entire charging cycle. For example, half of the air pocket is cut off.

[0071] The remaining air pockets can be used to contain the gas that may be generated in the third charging stage, ensuring that the gas generated in the third charging stage has enough space to expand and release, avoiding gas accumulation inside the battery cell, thereby reducing the pressure and damage to the battery cell structure. At the same time, it can also prevent the gas from leaking into the external environment through the sealed structure of the battery cell, causing safety hazards.

[0072] Accordingly, when the semi-finished battery cell is vacuumed, the extraction is stopped when the vacuum degree reaches a preset vacuum degree, wherein the preset vacuum degree is a relative vacuum degree, which can be set as required and is not limited here.

[0073] Step 104, charging the semi-finished battery cell until the charging voltage reaches a third cut-off voltage; the third cut-off voltage is greater than the second cut-off voltage.

[0074] In the third charging stage, the active substances inside the semi-finished battery cells are deeply activated by charging again, ensuring that the active materials in the battery cells can fully participate in the subsequent charging and discharging process, thereby increasing the service life of the finished battery cells.

[0075] The third charging stage does not impose too many restrictions on the formation pressure and formation current.

[0076] In some embodiments, the third set pressure of the third charging stage may be 1 MPa, and conventional pressure may be used.

[0077] In some embodiments, charging the semi-finished battery cell until the charging voltage reaches a third cut-off voltage includes: charging the semi-finished battery cell according to a third set current until the charging voltage reaches the third cut-off voltage, and the value range of the third set current is the current value range corresponding to 0.45-0.55C.

[0078] The third set current is set to be greater than the first set current, for example, the third set current is a current value corresponding to 0.5C, which speeds up the formation speed in the third charging stage, saves time, and improves efficiency.

[0079] In some embodiments, the third cut-off voltage has a value range of a voltage value corresponding to 50%-55% SOC. Reaching the third cut-off voltage also means that the charging and formation of the semi-finished battery cell is formally completed.

[0080] The third cut-off voltage is the voltage value corresponding to the sum of the charging power of the first charging stage, the charging power of the second charging stage, and the charging power of the third charging stage. For example, if the actual charging power of the first charging stage is 1% SOC, the charging power of the second charging stage is 9% SOC, and the charging power of the third charging stage is 40% SOC, then the third cut-off voltage is the voltage value corresponding to 50% SOC.

[0081] In the third charging stage, as the charging voltage increases, more active substances inside the semi-finished battery cells are further activated, allowing them to reach the optimal charge and discharge state, ensuring that the battery cells meet their designed capacity and performance requirements, stabilizing the structure and performance of the battery cells, reducing performance degradation and safety risks of the finished battery cells in subsequent use, and ensuring the service life of the finished battery cells.

[0082] The present application divides the formation stage into multiple small stages, namely the first charging stage, the second charging stage, the degassing stage and the third charging stage, and accurately controls the parameters of each stage. Appropriate processing conditions are set in each stage, which can not only improve the formation efficiency, but also reduce the gas production during the formation process, increase the exhaust volume, and improve the performance of the finished battery cell.

[0083] Step 105, encapsulating the semi-finished battery cells to obtain finished battery cells.

[0084] Finally, the semi-finished battery cells formed after three charging stages and degassing stages are packaged to obtain finished battery cells.

[0085] Users can divide the capacity of finished battery cells according to their needs and select the required battery cells.

[0086] The amount of gas in the finished battery cell obtained by the battery cell formation method described in the present application is greatly reduced, the SEI film is more uniform and dense, and accordingly, the service life of the finished battery cell is also improved. The following is proved by specific examples and data.

[0087] The 2Ah soft-pack battery cell is made of a ternary positive electrode material and a graphite negative electrode system through a stacking method. Its operating voltage is stable between 3.00-4.20V and is used as an example battery cell.

[0088] The formation conditions are as follows: In the first charging stage, under the first set pressure environment, the first set current is charged to the first cut-off voltage, that is, 3.00-3.10V, which is the voltage value corresponding to 1% SOC; in the second charging stage, under the second set pressure environment, the second set current is charged to the second cut-off voltage, that is, 3.60-3.65V, which is the voltage value corresponding to 10% SOC; according to the comparison needs, a degassing stage is set to implement vacuum operation and gas bag cutting operation; in the third charging stage, under the third set pressure environment, the third set current is charged to the third cut-off voltage, that is, 3.90-3.95V, which is the voltage value corresponding to 50%-55% SOC. The formation temperature of the entire formation stage is 25°C. As shown in Table 1, Table 1 is a schematic table of formation conditions for each stage of formation provided by the present application.

[0089] Table 1 Schematic diagram of the chemical conditions at each stage of chemical formation

[0090]

[0091] Table 1 clearly shows the formation conditions of each stage. The cut-off voltage has been defined in the previous text and is no longer shown in the table. Based on different formation conditions, different schemes are formed accordingly, namely, comparative example 1, comparative example 2, comparative example 3, embodiment 1, embodiment 2, embodiment 3 and embodiment 4 are formed.

[0092] Comparative Examples 1 and 2 are conventional formation schemes, and Comparative Example 3 adds vacuum treatment and air bag cutting treatment on the basis of the conventional scheme. Embodiment 1, Embodiment 2, Embodiment 3 and Embodiment 4 are schemes generated based on the battery cell formation method of the present application, in which the second set pressure is greater than the first set pressure, and vacuum treatment and air bag cutting treatment are added at the same time. Among them, the second set current is greater than the first set current, and the third set current is greater than the first set current.

[0093] Based on the above-mentioned formation conditions, the battery cells are formed and packaged to obtain the finished battery cells corresponding to different formation scenarios.

[0094] Test the interface conditions and capacity retention rates of the finished battery cells corresponding to different formation scenarios. As shown in Table 2, Table 2 is a schematic table of the interface conditions and capacity retention rates of the finished battery cells formed under different formation scenarios provided by the present application.

[0095] Among them, the 1C charge and discharge 100-cycle capacity retention rate refers to the percentage of the actual capacity of the finished battery cell to the initial capacity after 100 1C / 1C charge and discharge cycles.

[0096] Table 2 Schematic diagram of the interface conditions and capacity retention rate of finished battery cells formed under different formation scenarios

[0097] plan Interface 1C charge and discharge 100 cycles capacity retention rate Comparative Example 1 More bubbles, poor interface 95.5％ Comparative Example 2 More bubbles, poor interface 94.3％ Comparative Example 3 A small amount of bubbles 96.7％ Embodiment 1 No bubbles 98.2％ Embodiment 2 No bubbles 98.6％ Embodiment 3 No bubbles 99.1％ Embodiment 4 No bubbles 97.6％

[0098] Based on Table 2, it can be seen that the interface condition of the finished battery cell obtained by the formation scheme formulated according to the method described in this application is quite good. After the formation in the second charging stage, the vacuum operation and the air bag cutting operation are implemented to discharge the gas, which solves the problem of gas residue and bubble residue on the electrode interface. There are no bubbles on the electrode interface, which reduces the problems of battery cell displacement, battery cell corner damage and battery cell leakage caused by bubbles, and improves the service life of the finished battery cell.

[0099] Among them, the capacity retention rate represents the service life of the battery cell. This column of data just confirms what was mentioned in the previous paragraph, which improves the service life of the finished battery cell.

[0100] Comparing Example 1, Example 2, Example 3 and Example 4, it can be seen that the capacity retention rate of the finished battery cell corresponding to Example 4 is relatively poor, which can be attributed to the fact that the formation pressure in the first charging stage is too high, which affects the flow of the electrolyte and the wetting of the interface. It can be seen that the adjustment of pressure is crucial to the amount of gas, interface effect and battery life.

[0101] Pictures can more directly reflect the effect of the formation, such as Figure 2 As shown, Figure 2 This is an interface comparison diagram of a finished battery cell provided in an embodiment of the present application. Figure 2 The left side shows the interface of comparative example 1. Figure 2 The right side shows the interface of the first embodiment, based on Figure 2 It can be seen that the battery cell formation method described in the present application can discharge a large amount of gas inside the battery cell and form a relatively excellent electrode interface.

[0102] In summary, the present application adopts a multi-stage current formation, changes the formation pressure at each stage based on different current formations, and at the same time adds vacuum treatment and gas bag cutting treatment to reduce gas production and increase exhaust volume, thereby preparing a finished battery cell with a good interface and a long service life.

[0103] In the embodiment of the present application, it is divided into three charging stages, each stage corresponds to a specific cut-off voltage, and the semi-finished battery cells are charged and formed in stages. In the first two charging stages, the pressure and current are controlled, the semi-finished battery cells are placed in different pressure environments, and the semi-finished battery cells are charged with different set currents. Among them, the first charging stage uses a smaller pressure and current to reduce the output of gas, and the second charging stage increases the pressure and current to discharge the gas, while promoting the stability of the SEI film to avoid the unstable SEI film from being destroyed, resulting in increased gas production. After the second charging stage, vacuum treatment and gas bag cutting treatment are added to discharge the retained gas. Subsequently, the finished battery cell can be obtained through the final charging stage and packaging. The amount of gas in the finished battery cell is greatly reduced, which solves the problem of a large amount of gas in the finished battery cell.

[0104] See also Figure 3 , Figure 3 This is a structural diagram of a battery cell formation device provided in an embodiment of the present application. For the sake of ease of explanation, only the parts related to the embodiment of the present application are shown.

[0105] The cell interface formation device 300 includes: a first charging module 301 , a second charging module 302 , a degassing module 303 , a third charging module 304 , and a packaging module 305 .

[0106] The first charging module 301 is used to charge the semi-finished battery cell to be formed according to a first set current under a first set pressure environment until the charging voltage reaches a first cut-off voltage; the semi-finished battery cell corresponding to the first cut-off voltage has an SEI film that meets the first set requirements.

[0107] The second charging module 302 is used to charge the semi-finished battery cell according to a second set current under a second set pressure environment until the charging voltage reaches a second cut-off voltage; the second set pressure is greater than the first set pressure, the second set current is greater than the first set current, the second cut-off voltage is greater than the first cut-off voltage, and the semi-finished battery cell corresponding to the second cut-off voltage has an SEI film that meets the second set requirements.

[0108] The degassing module 303 is used to perform vacuum treatment and gas bag cutting treatment on the semi-finished battery cell.

[0109] The third charging module 304 is used to charge the semi-finished battery cell until the charging voltage reaches a third cut-off voltage; the third cut-off voltage is greater than the second cut-off voltage.

[0110] The packaging module 305 is used to package the semi-finished battery cells to obtain finished battery cells.

[0111] In some embodiments, the device further comprises a liquid injection and static module, which is used to:

[0112] The semi-finished battery cell filled with liquid is left to stand for a preset period of time to obtain the semi-finished battery cell to be formed.

[0113] In some embodiments, the degassing module is specifically used for:

[0114] When the semi-finished battery cell is subjected to air bag cutting processing, air bags of a preset capacity are cut off.

[0115] In some embodiments, the first set pressure is 0.3-2 MPa.

[0116] In some embodiments, the value range of the first set current is a current value range corresponding to 0.15-0.25C, and / or the value range of the second set current is a current value range corresponding to 0.45-0.55C.

[0117] In some embodiments, the first cut-off voltage has a value range of a voltage value corresponding to 1%-2% SOC, the second cut-off voltage has a value range of a voltage value corresponding to 8%-10% SOC, and / or the third cut-off voltage has a value range of a voltage value corresponding to 50%-55% SOC.

[0118] In some embodiments, the third charging module is specifically used for:

[0119] The semi-finished battery cell is charged according to a third set current until the charging voltage reaches the third cut-off voltage, and the value range of the third set current is a current value range corresponding to 0.45-0.55C.

[0120] The battery cell formation device provided in the embodiment of the present application can implement each process of the embodiment of the above-mentioned battery cell formation method and can achieve the same technical effect. To avoid repetition, it will not be described here.

[0121] An embodiment of the present application provides a battery cell, which is manufactured based on the above-mentioned battery cell formation method, that is, a finished battery cell. The battery cell has less gas inside and the battery cell life is greatly improved.

[0122] Figure 4 4 is a structural diagram of an electronic device provided in an embodiment of the present application. As shown in the figure, the electronic device 4 of the embodiment includes: at least one processor 40 ( Figure 4 Only one is shown in the figure), a memory 41, and a computer program 42 stored in the memory 41 and executable on the at least one processor 40, wherein the processor 40 implements the steps of any of the above-mentioned method embodiments when executing the computer program 42.

[0123] The electronic device 4 may be a computing device such as a desktop computer, a notebook, a PDA, or a cloud server. The electronic device 4 may include, but is not limited to, a processor 40 and a memory 41. Those skilled in the art will appreciate that Figure 4 It is only an example of the electronic device 4 and does not constitute a limitation of the electronic device 4. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the electronic device may also include input and output devices, network access devices, buses, etc.

[0124] The processor 40 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc.

[0125] The memory 41 may be an internal storage unit of the electronic device 4, such as a hard disk or memory of the electronic device 4. The memory 41 may also be an external storage device of the electronic device 4, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the electronic device 4. Further, the memory 41 may also include both an internal storage unit and an external storage device of the electronic device 4. The memory 41 is used to store the computer program and other programs and data required by the electronic device. The memory 41 may also be used to temporarily store data that has been output or is to be output.

[0126] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0127] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0128] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0129] In the embodiments provided in the present application, it should be understood that the disclosed devices / electronic devices and methods can be implemented in other ways. For example, the device / electronic device embodiments described above are merely schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0130] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0131] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0132] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present application implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electric carrier signal, telecommunication signal and software distribution medium. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0133] The present application implements all or part of the processes in the above-mentioned embodiment methods, and may also be implemented through a computer program product. When the computer program product runs on an electronic device, the electronic device can implement the steps in the above-mentioned method embodiments when the computer program product is executed.

[0134] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A battery cell formation method, characterized in that: include: Under a first set pressure environment, charging the semi-finished battery cell to be formed according to a first set current until the charging voltage reaches a first cut-off voltage; The semi-finished battery cell corresponding to the first cut-off voltage has an SEI film that meets the first set requirement; Under a second set pressure environment, the semi-finished battery cell is charged according to a second set current until the charging voltage reaches a second cut-off voltage; the second set pressure is greater than the first set pressure, the second set current is greater than the first set current, the second cut-off voltage is greater than the first cut-off voltage, and the semi-finished battery cell corresponding to the second cut-off voltage has an SEI film that meets the second set requirements; Performing vacuum treatment and air bag cutting treatment on the semi-finished battery cell; Charging the semi-finished battery cell until the charging voltage reaches a third cut-off voltage; the third cut-off voltage is greater than the second cut-off voltage; The semi-finished battery cells are packaged to obtain finished battery cells.

2. The method according to claim 1, characterized in that The method of charging the semi-finished battery cell to be formed according to the first set current under the first set pressure environment until the charging voltage reaches the first cut-off voltage also includes: The semi-finished battery cell filled with liquid is left to stand for a preset period of time to obtain the semi-finished battery cell to be formed.

3. The method according to claim 1, characterized in that The method further comprises: When the semi-finished battery cell is subjected to air bag cutting processing, air bags of a preset capacity are cut off.

4. The method according to claim 1, characterized in that: The first set pressure is 0.3-2 MPa.

5. The method according to claim 1, characterized in that The value range of the first set current is a current value range corresponding to 0.15-0.25C, and / or the value range of the second set current is a current value range corresponding to 0.45-0.55C.

6. The method according to claim 1, characterized in that The first cut-off voltage has a value range of 1%-2% SOC corresponding to the voltage value range, the second cut-off voltage has a value range of 8%-10% SOC corresponding to the voltage value range, and / or the third cut-off voltage has a value range of 50%-55% SOC corresponding to the voltage value range.

7. The method according to claim 1, characterized in that The step of charging the semi-finished battery cell until the charging voltage reaches a third cut-off voltage includes: The semi-finished battery cell is charged according to a third set current until the charging voltage reaches the third cut-off voltage, and the value range of the third set current is a current value range corresponding to 0.45-0.55C.

8. A battery cell formation device, characterized in that: include: A first charging module is used to charge the semi-finished battery cell to be formed according to a first set current under a first set pressure environment until the charging voltage reaches a first cut-off voltage; the semi-finished battery cell corresponding to the first cut-off voltage has an SEI film that meets the first set requirements; a second charging module, used for charging the semi-finished battery cell according to a second set current under a second set pressure environment until the charging voltage reaches a second cut-off voltage; the second set pressure is greater than the first set pressure, the second set current is greater than the first set current, the second cut-off voltage is greater than the first cut-off voltage, and the semi-finished battery cell corresponding to the second cut-off voltage has an SEI film that meets the second set requirements; A degassing module, used for performing a vacuum treatment and a gas bag cutting treatment on the semi-finished battery cell; a third charging module, used to charge the semi-finished battery cell until the charging voltage reaches a third cut-off voltage; the third cut-off voltage is greater than the second cut-off voltage; The packaging module is used to package the semi-finished battery cells to obtain finished battery cells.

9. A battery cell, characterized in that: The battery cell is manufactured based on the method according to any one of claims 1 to 7.

10. An electronic device, characterized in that: The electronic device comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the electronic device implements the method as claimed in any one of claims 1 to 7.

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