Battery production method

Abstract

The application relates to a battery preparation method. The method comprises the following steps: a battery preparation method, comprising the following steps: obtaining a winding battery cell to be processed; performing heat pressing treatment on the winding battery cell to be processed, and detecting whether the surface hardness of the winding battery cell after heat pressing reaches a preset hardness range; packaging the winding battery cell with the surface hardness reaching the preset hardness range into a shell as a target battery cell; and rejecting the winding battery cell with the surface hardness out of the preset hardness range. The scheme provided by the application can detect whether the surface hardness of the winding battery cell after heat pressing reaches the preset hardness range, package the winding battery cell with the surface hardness reaching the preset hardness range into the shell, reject the winding battery cell with the surface hardness not reaching the preset hardness range, effectively reduce the winding battery cell with excessive heat pressing entering the packaging-into-shell process, effectively improve the production quality of the battery, effectively improve the yield of the winding battery cell packaging into the shell, and thus improve the production efficiency of the battery.

Description

Technical Field

[0001] This application relates to the field of battery manufacturing technology, and in particular to a method for preparing a battery. Background Technology

[0002] Soft-pack lithium-ion batteries are prone to cell porosity issues during production, especially for wound cells, which can lead to low yield rates when the cells are packaged into the casing. To improve the battery packaging yield, high-temperature hot pressing of the cells before packaging is generally used to quickly shape the cells, alleviate the porosity problem, and thus improve the packaging yield.

[0003] In related technologies, the same hot-pressing process is generally used to hot-press cells of the same batch, that is, the same hot-pressing parameters are used to hot-press cells of the same batch. The above hot-pressing method is prone to some cells being over-hot-pressed or some cells being under-hot-pressed. When a cell is over-hot-pressed, under the same static conditions after electrolyte injection, the middle part of the over-hot-pressed cell will not be sufficiently wetted by electrolyte. As a result, after the cell is formed and tested, the battery product in which the cell is used is prone to lithium plating bumps, affecting production quality. When a cell is under-hot-pressed, the cell fluffing problem will still exist, affecting the subsequent cell packaging yield and production efficiency. Summary of the Invention

[0004] To address or partially address the problems existing in related technologies, this application provides a battery manufacturing method that can detect whether the surface hardness of the wound battery cell is within a preset hardness range after hot pressing. Wound battery cells with surface hardness reaching the preset hardness range are packaged into a casing, while wound battery cells with surface hardness not reaching the preset hardness range are rejected. This effectively reduces the number of over-hot-pressed wound battery cells entering the packaging process, effectively improves the production quality of the battery, and effectively increases the yield of wound battery cell packaging, thereby improving the production efficiency of the battery.

[0005] The first aspect of this application provides a method for manufacturing a battery, comprising:

[0006] Obtain the wound battery cells to be processed;

[0007] The wound battery cell to be processed is subjected to hot pressing, and the surface hardness of the wound battery cell after hot pressing is tested to see if it reaches the preset hardness range.

[0008] The wound battery cell with a surface hardness reaching a preset hardness range is used as the target battery cell and packaged into a shell.

[0009] The wound cells whose surface hardness is outside the preset hardness range are rejected.

[0010] In some implementations, the preset hardness range is obtained in the following way:

[0011] Obtain multiple test cells of the same model as the wound cell to be processed, and perform hot pressing treatment on the multiple test cells to different degrees;

[0012] Hardness tests were performed on each of the test cells after hot pressing to obtain the surface hardness of each test cell.

[0013] Each test cell was packaged into a casing, and the casing yield of all test cells was calculated.

[0014] The fully charged interface of the test cell in the disassembled and sized battery;

[0015] The surface hardness range of the test cell corresponding to the qualified casing yield and the fully charged interface is determined as the preset hardness range.

[0016] In some implementations, the method further includes:

[0017] Multiple surface hardness boundary values ​​are determined according to pre-defined rules;

[0018] The surface hardness of the test cells after multiple hot-pressing treatments corresponds to each surface hardness range formed between multiple surface hardness boundary values;

[0019] The step of determining the surface hardness range of the test cell corresponding to the qualified casing yield and the fully charged interface as the preset hardness range includes:

[0020] The surface hardness range corresponding to the surface hardness of the test cell corresponding to the qualified casing yield and the fully charged interface is determined as the preset hardness range.

[0021] In some embodiments, the preset hardness range is 50HD-90HD.

[0022] In some embodiments, detecting whether the surface hardness of the wound cell reaches a preset hardness range includes:

[0023] The wound cell is placed on a preset fixture, which has a centrally suspended structure, so that the bottom of the cell corresponding to the surface on the wound cell where the hardness value is measured is suspended.

[0024] The hardness value of the surface of the wound battery cell is obtained by a hardness measuring device, and it is determined whether the hardness value reaches the preset hardness range.

[0025] In some embodiments, obtaining the hardness value of the surface of the wound battery cell using a hardness measuring device includes:

[0026] The hardness value of the central region of the surface of the wound battery cell is obtained by using a hardness measuring device.

[0027] In some embodiments, prior to the hot pressing process, the method further includes:

[0028] Pre-acquire preset hot-pressing parameters;

[0029] The hot-pressing treatment of the wound battery cell to be processed includes:

[0030] The wound battery cell to be processed is subjected to hot pressing treatment according to the preset hot pressing parameters.

[0031] In some implementations, the qualified casing yield and the hot-pressing parameters of the test cell corresponding to the fully charged interface are determined as the preset hot-pressing parameters.

[0032] In some implementations, the preset hot-pressing parameters include temperature, pressure, and time.

[0033] In some embodiments, the temperature is 25°C-55°C, the pressure is 100kgf-400kgf, and the time is 1S-3S.

[0034] The technical solution provided in this application may include the following beneficial effects:

[0035] The technical solution of this application detects the surface hardness of the wound battery cell after hot pressing. The surface hardness of the wound battery cell characterizes the degree of completion of the hot pressing process. Wound battery cells with surface hardness reaching the preset hardness range are packaged into the casing, while wound battery cells with surface hardness not reaching the preset hardness range are rejected. This effectively reduces the number of over-hot-pressed wound battery cells entering the packaging process, effectively improves the production quality of the battery, and effectively increases the yield of wound battery cell packaging, thereby improving the production efficiency of the battery.

[0036] Furthermore, the technical solution of this application, by pre-obtaining preset hot-pressing parameters, wherein the preset hot-pressing parameters correspond to the qualified casing yield and the fully charged interface of the wound cell, uses the aforementioned preset hot-pressing parameters to perform hot-pressing treatment on the wound cell to be processed, effectively improving the accuracy of the hot-pressing treatment of the wound cell, and the surface hardness of the wound cell after hot-pressing treatment can be more in line with the surface hardness range of the qualified casing yield and the fully charged interface, thereby effectively preventing the wound cell from over-pressure. Moreover, by pre-determining the preset hardness range based on the qualified casing yield and the test cell with the fully charged interface, the accuracy of judging the degree of hot-pressing treatment of the wound cell can be further improved, thereby further improving the production quality of the battery.

[0037] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0038] The above and other objects, features and advantages of this application will become more apparent from the more detailed description of exemplary embodiments thereof in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments thereof.

[0039] Figure 1 This is a schematic flowchart illustrating the battery manufacturing method in the embodiments of this application;

[0040] Figure 2 This is another schematic diagram of the battery preparation method shown in the embodiments of this application. Detailed Implementation

[0041] Embodiments of this application will now be described in more detail with reference to the accompanying drawings. While embodiments of this application are shown in the drawings, it should be understood that this application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to make this application more thorough and complete, and to fully convey the scope of this application to those skilled in the art.

[0042] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0043] It should be understood that although the terms "first," "second," "third," etc., may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0044] In the production of soft-pack lithium-ion cells, especially wound cells, hot-pressing is typically used to shape the cells during production. This helps alleviate the problem of cell porosity and improves the yield when the cells are packaged into casings. Related technologies generally use the same hot-pressing process for cells in the same batch, i.e., using the same hot-pressing parameters. However, this method can easily result in some cells being over-pressed or under-pressed. When a cell is over-pressed, under the same static conditions after electrolyte filling, the middle part of the over-pressed cell may not be sufficiently wetted with electrolyte. This can lead to lithium plating marks in the battery products after capacity testing, affecting production quality. Conversely, if a cell is under-pressed, the porosity problem will persist, affecting the subsequent packaging yield and production efficiency.

[0045] In addition, related technologies generally involve increasing the settling time and temperature of the battery cell after hot pressing to promote sufficient electrolyte wetting. While these methods can improve the wetting effect within the battery cell to some extent, extending the settling time prolongs the overall production cycle and increases energy consumption, leading to higher production costs. Furthermore, prolonged high-temperature settling can damage the electrode structure within the battery cell. For example, prolonged high-temperature settling can affect the chemical properties of the active layer on the electrode, posing a risk of damaging the electrode structure and impacting the battery's electrical performance during long-cycle periods.

[0046] To address the aforementioned issues, this application provides a battery manufacturing method that can detect whether the surface hardness of the wound battery cell falls within a preset hardness range after hot pressing. Wound battery cells with surface hardness reaching the preset hardness range are packaged into a casing, while wound battery cells with surface hardness falling below the preset hardness range are rejected. This effectively reduces the number of over-hot-pressed wound battery cells entering the packaging process, effectively improves the production quality of the battery, and effectively increases the yield of wound battery cell packaging, thereby improving the production efficiency of the battery.

[0047] The technical solutions of the embodiments of this application are described in detail below with reference to the accompanying drawings.

[0048] Figure 1 This is a schematic flowchart illustrating a battery fabrication method according to an embodiment of this application. The battery fabrication method of this application is mainly used for soft-pack lithium-ion batteries fabricated from wound cells.

[0049] See Figure 1 The battery manufacturing method of this application includes:

[0050] S110, Obtain the wound battery cell to be processed.

[0051] In this step, the wound battery cell that has been completed is obtained.

[0052] It is understood that the battery manufacturing method of this application can be used for stacked and wound battery cells formed by electrode lamination. Specifically, the battery manufacturing method of this application is used to perform hot pressing processing before the wound battery cell is packaged. It is known that packaging the wound battery cell involves inserting the wound battery cell into an aluminum-plastic film, also known as the wound battery cell casing process.

[0053] S120 involves hot-pressing the wound battery cell to be processed and checking whether the surface hardness of the hot-pressed wound battery cell reaches the preset hardness range.

[0054] In this step, the obtained wound battery cell is hot-pressed, and after hot-pressing, the surface hardness of the wound battery cell is tested to see if it reaches a preset hardness range. It can be understood that the preset hardness range corresponds to the surface hardness of the wound battery cell. The preset hardness range can be a range of values. In this application, the surface hardness can be measured using the Shore hardness method.

[0055] S130, a wound battery cell with a surface hardness reaching a preset hardness range is packaged into a casing as the target battery cell.

[0056] In this step, when the surface hardness of the wound cell reaches a preset hardness range, it indicates that the hot-pressing process of the wound cell is complete and meets the requirements. The wound cell with a surface hardness reaching the preset hardness range is then used as the target cell for encapsulation into a casing to prepare the corresponding battery product. It can be understood that in this application, the surface hardness of the wound cell characterizes the degree of hot pressing; when the surface hardness of the wound cell reaches the preset hardness range, it indicates that the hot-pressing process of the wound cell is complete and meets the requirements.

[0057] S140, remove wound cells whose surface hardness is outside the preset hardness range.

[0058] In this step, if the surface hardness of the wound cell is detected to be outside the preset hardness range, it indicates that the hot pressing process of the wound cell does not meet the requirements, that is, the wound cell may be defective, and the wound cell with a surface hardness outside the preset hardness range is rejected.

[0059] It should be understood that there is no specific order between steps S130 and S140.

[0060] In this embodiment, the battery manufacturing method of this application detects the surface hardness of the wound cell after hot pressing. The surface hardness of the wound cell characterizes the degree of completion of the hot pressing process. Wound cells with surface hardness reaching a preset hardness range are packaged into the casing, while wound cells with surface hardness not reaching the preset hardness range are rejected. This effectively reduces the number of over-hot-pressed wound cells entering the packaging process, effectively improves the production quality of the battery, and effectively increases the yield of wound cell packaging, thereby improving the production efficiency of the battery.

[0061] Figure 2 This is another schematic diagram of the battery preparation method shown in the embodiments of this application.

[0062] See Figure 2 The battery manufacturing method of this application includes:

[0063] S210, Obtain the wound battery cell to be processed.

[0064] In this step, the wound battery cell that has been completed is obtained.

[0065] S220, pre-acquire preset hot pressing parameters.

[0066] In this step, preset hot-pressing parameters for hot-pressing the wound battery cell to be processed are obtained in advance. These preset hot-pressing parameters may correspond to the wound battery cell to be processed. For example, the preset hot-pressing parameters are obtained by performing performance analysis on multiple test cells of the same model as the wound battery cell to be processed after hot-pressing.

[0067] Among them, the preset hot-pressing parameters can be determined based on the hot-pressing parameters when hot-pressing test cells that meet the preset qualification conditions.

[0068] In this application, the wound battery cells to be processed are known; therefore, steps S210 and 220 can be performed in any order. It should be understood that the battery manufacturing method of this application can pre-set different preset hot-pressing parameters according to different batches of wound battery cells to be processed. That is to say, the battery manufacturing method of this application is applicable to the manufacturing of batteries of different batches and specifications.

[0069] In some embodiments, the preset hot-pressing parameters include temperature, pressure, and time. During the hot-pressing process, the wound battery cell is heated and pressurized according to the preset hot-pressing parameters of temperature, pressure, and time. It is understood that the hot-pressing process can be implemented using hot-pressing equipment in related technologies, which will not be elaborated here. Further, the temperature can be 25℃-55℃, the pressure can be 100 kgf-400 kgf, and the time can be 1-3 seconds. Using the above-mentioned preset hot-pressing parameters to perform hot-pressing treatment on the wound battery cell can effectively improve the accuracy of the hot-pressing process.

[0070] S230 performs hot pressing on the wound battery cell to be processed according to the preset hot pressing parameters, and detects whether the surface hardness of the wound battery cell reaches the preset hardness range.

[0071] In this step, the wound battery cell to be processed is subjected to hot pressing treatment according to the obtained preset hot pressing parameters. It is understood that the hot pressing process can be implemented by hot pressing equipment in related technologies, which will not be elaborated here. After the hot pressing treatment, the surface hardness of the wound battery cell is checked to see if it reaches a preset threshold.

[0072] The hot pressing process can consist of a single or multiple hot pressing steps. For example, hot pressing a wound battery cell can be a single hot pressing process with a temperature of 30°C, a pressure of 200 kgf, and a duration of 2 seconds. Alternatively, hot pressing a wound battery cell can be a double hot pressing process with a temperature of 30°C, a pressure of 200 kgf, and a duration of 1 second.

[0073] In some implementations, the preset hardness range is obtained in the following ways:

[0074] S231a: Obtain multiple test cells of the same model to be processed from the wound cells, and perform hot pressing treatment on the multiple test cells to different degrees.

[0075] The test cells can be of the same model as the wound cells to be processed, meaning they share the same model, specifications, and other parameters. In other words, the test cells can be from the same batch as the wound cells to be processed. Multiple test cells are subjected to different degrees of hot-pressing treatment, resulting in different surface hardnesses after the treatment. This can be achieved by adjusting the heating temperature, pressure, and duration of the hot-pressing process, thus allowing for different degrees of hot-pressing treatment and different surface hardnesses for each test cell.

[0076] S232a, perform hardness testing on each test cell after hot pressing to obtain the surface hardness of the test cell.

[0077] The surface hardness of each test cell after hot pressing is tested to obtain the surface hardness of each test cell.

[0078] S233a, each test cell is packaged into a casing, and the casing yield of all test cells is calculated.

[0079] Each tested cell was packaged into a casing, and the casing yield of all tested cells was calculated. It should be understood that the casing yield corresponds to the probability that there are no defects during the winding and packaging process of the cell, such as no casing damage, poor sealing, or other defects.

[0080] S234a, the fully charged interface of the test cell in the battery after disassembly, formation, and capacity testing.

[0081] After each test cell is packaged and encapsulated, it forms a battery. After all the batteries have been formed and tested, they are charged to full capacity and then the full-charge interface of the test cell is disassembled.

[0082] S235a, the qualified casing yield and the surface hardness range of the test cell corresponding to the fully charged interface are determined as the preset hardness range.

[0083] The surface hardness range corresponding to the test cells with qualified in-cell yield and fully charged interface is defined as the preset hardness range. Qualified in-cell yield and fully charged interface test cells can be test cells with an in-cell yield greater than 99% and no interface lithium plating.

[0084] It can be understood that the two surface hardness values ​​corresponding to the boundary values ​​in the preset hardness range are the two test cells with qualified casing yield and full-charge interface and the minimum and maximum surface hardness.

[0085] The preset hardness range determined by the above method corresponds to the winding cell with qualified casing yield and full charge interface. In this way, the preset hardness range can be used to quickly determine whether the winding cell after hot pressing meets the production requirements.

[0086] In some implementations, the preset hardness range can be 50HD-90HD.

[0087] In some embodiments, multiple surface hardness boundary values ​​can be determined according to predefined rules; the surface hardness of multiple hot-pressed test cells corresponds to various surface hardness intervals formed between the multiple surface hardness boundary values; the surface hardness intervals corresponding to the surface hardness of the test cells with qualified casing yield and full-charge interface are determined as the preset hardness range. That is, the preset hardness range in this application is also obtained through the following methods:

[0088] S231b, pre-defined rules determine multiple surface hardness boundary values.

[0089] It is understandable that the surface hardness of test cells after different degrees of hot pressing treatment will fall into various surface hardness ranges formed by multiple surface hardness boundary values. For example, by dividing the surface hardness boundary values ​​at equal intervals, the surface hardness boundary values ​​can be: 10HD, 20HD, 30HD, 40HD...90HD, 100HD, forming surface hardness ranges of: <10HD, 10HD-20HD...80HD-90HD, and >90HD. Of course, the surface hardness boundary values ​​can also be customized according to actual application requirements. For example, the surface hardness boundary values ​​can be: 50HD, 60HD, 70HD, 80HD, 90HD, forming surface hardness ranges of: <50HD, 50HD to 60HD, 60HD to 70HD, 70HD to 80HD, 80HD to 90HD, and >90HD.

[0090] S232b: Obtain multiple test cells of the same model to be processed from the wound battery cells, and perform hot pressing treatment on the multiple test cells to different degrees. The surface hardness of the multiple test cells after hot pressing treatment corresponds to each surface hardness range formed between multiple surface hardness boundary values.

[0091] After the test cells underwent hot-pressing treatment to varying degrees, the surface hardness of the multiple test cells that completed the hot-pressing treatment corresponded to different surface hardness ranges formed between multiple surface hardness boundary values. It should be understood that different degrees of hot-pressing treatment means hot-pressing the test cells to their respective surface hardness ranges.

[0092] For example, the surface hardness ranges are: <50HD, 50HD to 60HD, 60HD to 70HD, 70HD to 80HD, 80HD to 90HD, and >90HD. By heating multiple test cells, each of the above ranges has at least 5 corresponding test cells, that is, each of the above ranges has at least 5 test cells corresponding to the surface hardness.

[0093] S233b performs hardness testing on each test cell after hot pressing to obtain the surface hardness of the test cell.

[0094] S234b: Package each test cell into a casing and calculate the casing yield of all test cells.

[0095] S235b, the fully charged interface of a test cell in a disassembled and sized battery.

[0096] S236b defines the surface hardness range corresponding to the surface hardness of the test cell at the qualified casing yield and the fully charged interface as the preset hardness range.

[0097] After determining the surface hardness range for each test cell, the surface hardness range corresponding to the surface hardness of the test cells with acceptable in-cell yield and full-charge interface is defined as the preset hardness range. As mentioned earlier, the test cells with acceptable in-cell yield and full-charge interface can be test cells with an in-cell yield greater than 99% and no interface lithium plating. Therefore, the preset hardness range can be the surface hardness range corresponding to the test cells that meet the above conditions.

[0098] To further understand the process of determining the preset hardness range in this application, the following uses four surface hardness ranges—<50HD, 50HD-70HD, 70HD-90HD, and >90HD—as examples to illustrate the process. Each range corresponds to 100 test cells, and the surface hardness values ​​of each test cell may be the same or different within the corresponding range. The results are shown in Table 1 below:

[0099]

[0100] Table 1

[0101] Based on the data results in Table 1 above, it can be seen that in the <50HD surface hardness zone, all tested cells did not exhibit interface lithium plating, but the encapsulation quality rate was 96%, which is low. In the 50HD-70HD surface hardness zone, all tested cells did not exhibit interface lithium plating, and the encapsulation quality rate was 99%, which is high. In the 70HD-90HD surface hardness zone, all tested cells did not exhibit interface lithium plating, and the encapsulation quality rate was 99%, which is high. In the >90HD surface hardness zone, all tested cells exhibited interface lithium plating, and the encapsulation quality rate was 99%, which is high.

[0102] Therefore, based on the data results in Table 1, it can be determined that 50HD-90HD is the surface hardness range that meets the preset yield conditions. Within this surface hardness range, the wound cell can ensure a better packaging yield and no interface lithium plating occurs.

[0103] In some implementations, the hot-pressing parameters of the test cells corresponding to the qualified casing yield and the fully charged interface can also be determined as preset hot-pressing parameters.

[0104] It is understandable that after determining the qualified casing yield and the test cell corresponding to the fully charged interface, the preset hot-pressing parameters for hot-pressing the wound cell to be processed are determined based on the hot-pressing parameters used when hot-pressing the test cell that meets the conditions of qualified casing yield and fully charged interface. It is also understood that the hot-pressing parameters used when hot-pressing the test cell corresponding to the qualified casing yield and fully charged interface are suitable for producing target cells that meet preset conditions (i.e., preset hardness range). By determining the preset hot-pressing parameters using the above method, and then using the determined preset hot-pressing parameters to hot-press the wound cell to be processed, the accuracy of hot-pressing the wound cell can be effectively improved, and the surface hardness of the hot-pressed wound cell can more closely match the surface hardness range corresponding to the preset hardness range, thereby effectively preventing over-pressure from occurring in the wound cell.

[0105] In some embodiments, the surface hardness detection of the wound battery cell can be performed simultaneously with the hot pressing of the wound battery cell; that is, the wound battery cell is hot-pressed and its surface hardness is obtained at the same time. In other embodiments, the surface hardness detection of the wound battery cell can be performed separately from the hot pressing of the wound battery cell. For example, after hot pressing the wound battery cell for a period of time, the hot pressing is stopped, and then the surface hardness of the wound battery cell is detected. This process is repeated. In other words, the hot pressing of the wound battery cell can consist of multiple hot pressing processes of the same duration. For example, the duration of each hot pressing process can be 1 second. After each hot pressing process, the surface hardness of the wound battery cell is checked to see if it has reached a preset threshold.

[0106] In some implementations, detecting whether the surface hardness of the wound cell reaches a preset threshold may include:

[0107] S231c, the wound cell is placed on a preset fixture, which can be a centrally suspended structure so that the bottom of the cell corresponding to the surface on the wound cell where the hardness value is measured is suspended.

[0108] The pre-set fixture is compatible with the wound battery cell, and the wound battery cell, after undergoing a pre-set hot-pressing treatment, is placed in the pre-set fixture. During the measurement of the surface hardness value of the wound battery cell, there is no support at the bottom of the wound battery cell, thereby reducing the influence of the force generated by the support on the hardness value measurement process. Furthermore, the suspended structure in the middle of the pre-set fixture can achieve a faster cooling effect on the wound battery cell, thereby reducing the impact of the residual high temperature on the surface of the wound battery cell after the hot-pressing treatment on the hardness value measurement process.

[0109] S232c obtains the hardness value of the surface of the wound battery cell through a hardness measuring device and determines whether the hardness value reaches the preset hardness range.

[0110] The hardness value of the wound battery cell surface is obtained using a hardness measuring device to determine whether the hardness value reaches a pre-defined hardness range. It can be understood that when the hardness value reaches the pre-defined range, the hot-pressing treatment of the wound battery cell is considered to meet the requirements. The hardness measuring device can be a Shore hardness tester; there are no restrictions here.

[0111] In some implementations, the hardness value of the central region of the wound cell surface can be obtained using a hardness measuring device. In other words, by measuring the hardness value of the central region of the wound cell surface during the measurement process, the influence of the supporting force provided by the pre-set fixture on the wound cell can be further reduced, thereby improving the accuracy of the hardness measurement of the wound cell surface.

[0112] S240, a wound battery cell with a surface hardness reaching a preset hardness range is packaged into a casing as the target battery cell.

[0113] In this step, when the surface hardness of the wound cell reaches a preset hardness range, it indicates that the hot-pressing process of the wound cell is complete and meets the requirements. The wound cell with a surface hardness reaching the preset hardness range is then used as the target cell for encapsulation into a casing to prepare the corresponding battery product. It can be understood that in this application, the surface hardness of the wound cell characterizes the degree of hot pressing; when the surface hardness of the wound cell reaches the preset hardness range, it indicates that the hot-pressing process of the wound cell is complete and meets the requirements.

[0114] S250 removes wound cells whose surface hardness is outside the preset hardness range.

[0115] In this step, if the surface hardness of the wound cell is detected to be outside the preset hardness range, it indicates that the hot pressing process of the wound cell does not meet the requirements, that is, the wound cell may be defective, and the wound cell with a surface hardness outside the preset hardness range is rejected.

[0116] It should be understood that there is no specific order between steps S250 and S260.

[0117] In this embodiment, the battery manufacturing method of this application obtains preset hot-pressing parameters in advance. These preset hot-pressing parameters correspond to the qualified casing yield and the fully charged interface of the wound cell. The wound cell to be processed is then hot-pressed using the preset hot-pressing parameters, which effectively improves the accuracy of the hot-pressing process of the wound cell. Furthermore, the surface hardness of the hot-pressed wound cell can better match the surface hardness range of the qualified casing yield and the fully charged interface, thereby effectively preventing over-pressure from occurring in the wound cell. In addition, by pre-determining the preset hardness range based on the qualified casing yield and the fully charged interface of the test cell, the accuracy of judging the degree of hot-pressing of the wound cell can be further improved, thereby further improving the quality of the resulting battery production.

[0118] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method of making a battery, characterized by, The method comprises the following steps: acquiring a winding battery cell to be processed; performing heat pressing treatment on the winding battery cell to be processed, and detecting whether the surface hardness of the winding battery cell after heat pressing treatment reaches a preset hardness range; wherein, the preset hardness range is obtained by the following method: acquiring a plurality of test battery cells of the same model as the winding battery cell to be processed, and performing different degrees of heat pressing treatment on the plurality of test battery cells; performing hardness testing on each test battery cell after heat pressing treatment, and acquiring the surface hardness of each test battery cell; packaging each test battery cell into a shell, and counting the shell packaging yield of all test battery cells; disassembling the full-charge interface of the test battery cell in the battery after cell breaking and capacity grading; determining the surface hardness range of the test battery cell corresponding to the qualified shell packaging yield and the full-charge interface as the preset hardness range; the test battery cell corresponding to the qualified shell packaging yield and the full-charge interface is a test battery cell with a shell packaging yield greater than or equal to 99% and no interface lithium precipitation phenomenon; packaging the winding battery cell with the surface hardness reaching the preset hardness range into a shell as a target battery cell; rejecting the winding battery cell with the surface hardness outside the preset hardness range.

2. The production method according to claim 1, characterized by, The method further comprises the following steps: determining a plurality of surface hardness boundary values according to a pre-dividing rule; the surface hardness of each test battery cell after heat pressing treatment corresponds to a surface hardness interval formed between a plurality of surface hardness boundary values; determining the surface hardness range of the test battery cell corresponding to the qualified shell packaging yield and the full-charge interface as the preset hardness range comprises: determining the surface hardness interval corresponding to the surface hardness of the test battery cell corresponding to the qualified shell packaging yield and the full-charge interface as the preset hardness range.

3. The preparation method according to claim 1, characterized in that, The preset hardness range is 50HD-90HD.

4. The method of claim 1, wherein, The detection of whether the surface hardness of the winding battery cell reaches the preset hardness range comprises: placing the winding battery cell on a preset clamp, the preset clamp being a structure with a suspended middle part, so that the surface of the winding battery cell for measuring the hardness value corresponds to a suspended bottom of the battery cell; acquiring the hardness value of the surface of the winding battery cell by a hardness measuring device, and judging whether the hardness value reaches the preset hardness range.

5. The preparation method according to claim 4, characterized in that, The acquisition of the hardness value of the surface of the winding battery cell by the hardness measuring device comprises: acquiring the hardness value of the middle region of the surface of the winding battery cell by the hardness measuring device.

6. The method of claim 1, wherein, Before the heat pressing treatment, the method further comprises the following steps: pre-acquiring a preset heat pressing parameter; the heat pressing treatment on the winding battery cell to be processed comprises: performing heat pressing treatment on the winding battery cell to be processed according to the preset heat pressing parameter.

7. The production method according to claim 6, characterized by, The heat pressing parameter of the test battery cell corresponding to the qualified shell packaging yield and the full-charge interface is determined as the preset heat pressing parameter.

8. The preparation method according to claim 6, characterized in that, The preset heat pressing parameter comprises temperature, pressure and time.

9. The production method according to claim 8, characterized by, The temperature is 25℃-55℃, the pressure is 100 kgf-400kgf, and the time is 1S-3S.

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