Battery cell preparation method and battery cell

Abstract

The invention provides a battery cell preparation method and a battery cell, and belongs to the technical field of battery preparation technology.The battery cell preparation method comprises the steps that in a high-temperature environment, a positive plate, a diaphragm and a negative plate are conveyed to a processing platform through a conveying device, so that the positive plate, the diaphragm and the negative plate are stacked on the processing platform to form a pole group; carrying out lamination or winding treatment on the pole group on the processing platform; carrying out hot-pressing shaping on the pole group on the processing platform to obtain a naked battery cell; wherein the environment temperature of the high-temperature environment is 60-70 DEG C. According to the battery cell preparation method disclosed by the invention, the smoothness of the preparation process is effectively improved, the time required by a hot-pressing process in the preparation process is shortened, and the overall production efficiency of the battery cell is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of battery preparation technology, and in particular to a battery cell preparation method and a battery cell. Background Art

[0002] With the development of new energy power battery technology, new energy pure electric vehicles have developed rapidly. The development of battery cell technology is the core of the development of new energy vehicles. The battery cell is mainly composed of four major materials: positive electrode sheet, negative electrode sheet, diaphragm, and electrolyte. The soft-pack battery cell is encapsulated with aluminum-plastic film, and the cylindrical or square shell battery cell is encapsulated with aluminum shell / steel shell.

[0003] In the process of manufacturing the battery cell, it is necessary to ensure the precise fit between the positive electrode sheet, the separator, and the negative electrode sheet so that lithium ions can be transmitted smoothly. The current method is to perform hot pressing and shaping on the stacked or wound electrode assembly after the stacking or winding is completed to ensure the fit of the interface and make the electrode assembly thickness meet the design thickness requirements.

[0004] In order to confirm the effectiveness of hot pressing, two methods are usually used. The first method is to use a longer hot pressing time under fixed temperature and pressure conditions to make the internal temperature rise to a certain height and maintain it for a period of time. The specific time is set according to the thickness and size of the electrode group. The second method is to preheat the electrode group to be hot pressed before hot pressing, so that the battery cell reaches an ideal temperature before hot pressing, thereby improving the efficiency of hot pressing. However, both of the above methods will affect the production cycle in actual production and affect the overall efficiency of the battery cell production process.

[0005] Therefore, it is necessary to design a battery cell preparation method and a battery cell to reduce the time required for hot pressing and compounding of the electrode group, thereby solving the above problems. Summary of the invention

[0006] In view of the above shortcomings of the prior art, the present invention provides a battery cell preparation method and a battery cell, which can complete the preheating of the positive electrode sheet, the separator and the negative electrode sheet during the transmission process, so as to solve the technical problem that the existing battery cell preparation process needs to spend time separately to heat the electrode group before hot pressing, which affects the production rhythm in actual production and reduces the overall production efficiency of the battery cell.

[0007] In order to achieve the above-mentioned object and other related objects, the present invention provides a method for preparing a battery cell, the method comprising:

[0008] In a high temperature environment, the positive electrode sheet, the separator and the negative electrode sheet are conveyed to a processing platform by a conveying device, so that the positive electrode sheet, the separator and the negative electrode sheet are stacked into an electrode group on the processing platform; the electrode group is laminated or wound on the processing platform; the electrode group is hot pressed and shaped on the processing platform to obtain a bare battery cell. The ambient temperature of the high temperature environment is 60°C to 70°C.

[0009] In one example of the present invention, on the conveying path, the positive electrode sheet, the negative electrode sheet and the separator are respectively infrared heated by an infrared heating device.

[0010] In one example of the present invention, for the positive electrode sheet, infrared heating is performed using infrared light that matches the absorption band of the positive electrode material in the positive electrode sheet; for the negative electrode sheet, infrared heating is performed using infrared light that matches the absorption band of the negative electrode material in the negative electrode sheet.

[0011] In an example of the present invention, the infrared heating power P of the infrared heating device is 400W to 2000W, and the heating stroke L of the infrared heating device is 0.2m to 0.5m.

[0012] In an example of the present invention, the heating parameters of the infrared heating device for the positive electrode sheet, the negative electrode sheet and the diaphragm during the transmission process include the infrared heating power P, the heating stroke L and the set temperature rise ΔT, and the heating parameters satisfy the relationship: Among them, m is the mass of the heated material, β is the absorption efficiency of the heated material, and v is the transmission speed of the heated material.

[0013] In an example of the present invention, the electrode group is stacked in the order of the separator, the negative electrode sheet, the separator, and the positive electrode sheet.

[0014] In an example of the present invention, hot pressing and shaping the electrode group on the processing platform to obtain a bare battery cell includes: hot pressing the electrode group on the processing platform by hot rolling.

[0015] In an example of the present invention, the electrode group is hot pressed and shaped on the processing platform to obtain a bare battery cell, including: hot pressing the electrode group on the processing platform by pressing an upper hot pressing plate and a lower hot pressing plate, wherein the lower hot pressing plate is arranged on the processing platform, the electrode group is arranged on the lower hot pressing plate, and the upper hot pressing plate applies pressure to the electrode group above the lower hot pressing plate.

[0016] In one example of the present invention, the upper hot pressing plate and the lower hot pressing plate cooperate to apply a pressure of 5 to 15 tons to the pole group, the temperature of the pressure surface of the upper hot pressing plate and the lower hot pressing plate is 85°C to 110°C, and the hot pressing time is 10 to 300s.

[0017] The present invention provides a battery cell, which is prepared by the battery cell preparation method described in any one of the above examples.

[0018] The battery cell preparation method of the present invention performs the battery cell manufacturing process in a high temperature environment of 60°C to 70°C, and preheats the positive electrode sheet, the negative electrode sheet and the separator during transportation, so that the electrode group of the positive electrode sheet, the negative electrode sheet and the separator stacked on the processing platform is always at the ideal processing temperature before hot pressing, so that the electrode group on the processing platform is still maintained within the ideal processing temperature range after lamination or winding, so that the hot pressing process can be directly performed to obtain the bare battery cell without separate preheating. It can be seen that the battery cell preparation method effectively improves the fluency of the preparation process, shortens the time required for the hot pressing process in the preparation process, and improves the overall production efficiency of the battery cell. Therefore, the present invention effectively overcomes some practical problems in the prior art and has high utilization value and use significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, 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 invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 It is a schematic diagram of the process of preparing a battery cell in one embodiment of the present invention;

[0021] Figure 2 Schematic diagram of a process for preparing a battery cell in one embodiment of the present invention;

[0022] Figure 3 Schematic diagram of the structure of a battery cell preparation device in one embodiment of the present invention.

[0023] Component number description

[0024] 100, conveying device; 200, processing platform; 210, lower hot pressing plate; 220, upper hot pressing plate; 300, heating device; 400, positive electrode sheet; 500, negative electrode sheet; 600, diaphragm. DETAILED DESCRIPTION

[0025] The following is an explanation of the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the features in the following embodiments and the embodiments can be combined with each other without conflict. It should also be understood that the terms used in the embodiments of the present invention are intended to describe specific embodiments, rather than to limit the scope of protection of the present invention. The test methods for which specific conditions are not specified in the following examples are usually carried out under conventional conditions or according to the conditions recommended by the manufacturers.

[0026] It should be noted that the terms such as "upper", "lower", "left", "right", "middle" and "one" etc. used in this specification are only for the convenience of description and are not intended to limit the scope of implementation of the present invention. Changes or adjustments to their relative relationships, without substantially changing the technical content, should also be regarded as the scope of implementation of the present invention.

[0027] See also Figure 1 and Figure 2 The present invention provides a method for preparing a battery cell, which places the process of stacking and winding the battery cell in a high temperature environment of 60°C to 70°C, and preheats the positive electrode sheet, the negative electrode sheet and the separator during the entire preparation process, so that the inside and outside of the electrode group stacked on the processing platform are at a preset temperature, so that the electrode group can be directly hot-pressed without separate preheating, thereby greatly shortening the time required for the hot pressing process and improving the overall production efficiency of the battery cell.

[0028] like Figure 1 and Figure 2 As shown, the battery cell preparation method of the present invention is carried out in a high temperature environment, wherein the high temperature environment covers the conveying, stacking, lamination or winding process of the positive electrode sheet 400, the negative electrode sheet 500 and the separator 600, and the ambient temperature of the high temperature environment is 60°C to 70°C, which can make the positive electrode sheet 400, the negative electrode sheet 500 and the separator 600 uniformly preheated to the ideal hot pressing processing temperature during the conveying process without affecting the chemical properties of the positive electrode sheet 400, the negative electrode sheet 500 and the separator 600, and maintain the temperature before the hot pressing process. It should be noted that the high temperature environment in the present invention can be achieved by using equipment and methods known in the art.

[0029] like Figure 1 and Figure 2 As shown, the battery cell preparation method comprises the following steps:

[0030] S1. The positive electrode sheet 400, the separator 600 and the negative electrode sheet 500 are transferred to the processing platform 200 by the transfer device 100, so that the positive electrode sheet 400, the separator 600 and the negative electrode sheet 500 are stacked into an electrode group on the processing platform 200;

[0031] S2, laminating or winding the electrode group on the processing platform 200;

[0032] S3, hot pressing and shaping the electrode group to obtain a bare battery cell.

[0033] like Figure 1 and Figure 3 As shown, step S1 includes, respectively conveying the positive electrode sheet 400, the negative electrode sheet 500 and the separator 600 to the processing platform 200 according to a preset path through multiple independent conveying devices 100, so that the positive electrode sheet 400, the negative electrode sheet 500 and the separator 600 are stacked into an electrode group on the processing platform 200 according to a set order.

[0034] Among them, the positive electrode sheet 400, the negative electrode sheet 500 and the separator 600 conveyed to the processing platform 200 are stacked into a pole group in the order of separator 600, negative electrode sheet 500, separator 600 and positive electrode sheet 400 along the thickness direction (for example, from bottom to top on the processing platform 200, or from close to the platform to away from the platform).

[0035] like Figure 1 and Figure 3 As shown, in some embodiments, in step S1, multiple conveying devices 100 convey the positive electrode sheet 400, the negative electrode sheet 500 and the separator 600 to the conveying path of the processing platform 200, and multiple heating devices 300 perform infrared heating on the positive electrode sheet 400, the negative electrode sheet 500 and the separator 600 passing through. Among them, the infrared light sources of multiple heating devices 300 are respectively extended along the conveying paths of the positive electrode sheet 400, the negative electrode sheet 500 and the diaphragm 600, and the light sources of multiple heating devices 300 are correspondingly arranged on both sides of the conveying paths of the positive electrode sheet 400, the negative electrode sheet 500 and the diaphragm 600, so as to heat both sides of the positive electrode sheet 400, the negative electrode sheet 500 and the diaphragm 600 at the same time, so that the front and back sides of the positive electrode sheet 400, the negative electrode sheet 500 and the diaphragm 600 are quickly and evenly preheated to 60℃~70℃ before being conveyed to the processing platform 200, so that the inside and outside of the electrode group stacked by the positive electrode sheet 400, the negative electrode sheet 500 and the diaphragm 600 are uniformly within the temperature range of 60℃~70℃.

[0036] In some embodiments, in step S1, when heating the positive electrode sheet 400, the heating device 300 uses infrared light that matches the absorption band of the positive electrode material in the positive electrode sheet 400 to perform infrared heating to improve the heating efficiency of the positive electrode sheet 400, so that the positive electrode sheet 400 is quickly heated to a temperature range of 60°C to 70°C; when heating the negative electrode sheet 500, the heating device 300 uses infrared light that matches the absorption band of the negative electrode material in the negative electrode sheet 500 to perform infrared heating to improve the heating efficiency of the negative electrode sheet 500, so that the negative electrode sheet 500 is quickly heated to a temperature range of 60°C to 70°C.

[0037] The heating parameters of the infrared heating device 300 for the positive electrode sheet 400, the negative electrode sheet 500 and the diaphragm 600 during the transmission process include infrared heating power P, heating stroke L and set temperature rise ΔT, where the infrared heating power P is the average power output by the infrared light source in the infrared heating device 300, the heating stroke L is the illumination heating distance of the infrared heating device 300 along the transmission path of the positive electrode sheet 400, the negative electrode sheet 500 and the diaphragm 600, and the set temperature rise ΔT is the temperature to which the infrared heating device 300 needs to heat the positive electrode sheet 400, the negative electrode sheet 500 and the diaphragm 600.

[0038] In some embodiments, the infrared heating power P of the infrared heating device 300 is set to 400W~2000W, for example, the infrared heating power P can be set to 400W, 600W, 800W, 1000W, 1200W, 1400W, 1600W, 1800W or 2000W, and the heating stroke L of the infrared heating device 300 on the transmission path is set to 0.2m~0.5m, for example, the heating stroke L can be set to 0.2m, 0.3m, 0.4m or 0.5m.

[0039] In an optional embodiment, the infrared heating power P and the heating stroke L specifically adopted by the infrared heating device 300 during preparation can be specifically adjusted within a preset range according to the materials of the heated positive electrode sheet 400, the negative electrode sheet 500 and the diaphragm 600, the speed of passing through the heating area and the set temperature rise ΔT. Specifically, the heating parameters of the infrared heating device 300 satisfy the following relationship: m is the mass of the heated material, β is the absorption efficiency of the heated material, and v is the conveying speed of the heated material. The infrared heating power P and the heating stroke L of the infrared heating device 300 set in this example can effectively ensure that the positive electrode sheet 400, the negative electrode sheet 500 and the diaphragm 600 passing through are quickly and evenly heated to a temperature range of 60°C to 70°C, and maintain the uniform temperature of the positive electrode sheet 400, the negative electrode sheet 500 and the diaphragm 600 in the high temperature environment of the equipment environment.

[0040] In step S2, during the lamination or winding process of the electrode group, the positive electrode sheet 400, the negative electrode sheet 500 and the separator 600 in the electrode group are maintained in the temperature range of 60°C to 70°C under the heat preservation effect of the ambient temperature; in step S3, before hot pressing, the inside and outside of the laminated or wound electrode group are still uniformly in the temperature range of 60°C to 70°C, ensuring that when the hot pressing process starts, the initial processing temperature of the electrode group is 60°C to 70°C, so that hot pressing can be carried out directly without preheating.

[0041] It can be seen that the battery cell preparation method of the present invention eliminates the preheating link of the electrode group in the hot pressing process step, saves the time for preheating the electrode group to 60℃~70℃ after winding or lamination, greatly shortens the time required for the hot pressing process, and improves the overall preparation efficiency of the bare battery cell. Among them, after measurement, the time required to preheat the electrode group to 60℃~70℃ after winding or lamination by hot pressing accounts for 50%~60% of the total time of the original hot pressing process, that is, the preparation method can save 50%~60% of the process time in the hot pressing process compared with the original preparation method.

[0042] It should be noted that, in step S2, the electrode groups simply stacked on the processing platform 200 may be laminated or wound using equipment and methods known in the art.

[0043] It should be noted that, in step S3, the simply stacked electrode groups on the processing platform 200 may be hot-pressed using equipment and methods known in the art to obtain a composite electrode group.

[0044] For example, in some embodiments, in step S3, the electrode group that has been wound or laminated is hot-pressed and shaped by hot roller pressing on the processing platform 200.

[0045] For example, in some other embodiments, in step S3, the electrode group that has been wound or laminated is hot pressed and shaped by pressing the upper hot pressing plate 220 and the lower hot pressing plate 210 on the processing platform 200. The lower hot pressing plate 210 is arranged on the table of the processing platform 200, and the upper hot pressing plate 220 is correspondingly arranged above the lower hot pressing plate 210. Figure 3 As shown, during hot pressing, the electrode group that has been wound or stacked is transferred to the lower hot pressing plate 210 on the processing platform 200, and the pressure surfaces of the upper hot pressing plate 220 and the lower hot pressing plate 210 begin to heat up. When the pressure surfaces of the upper hot pressing plate 220 and the lower hot pressing plate 210 rise to the set hot pressing temperature, the upper hot pressing plate 220 moves toward the processing platform 200 to cooperate with the electrode group on the lower hot pressing plate 210 for hot pressing.

[0046] During hot pressing, the upper hot pressing plate 220 and the lower hot pressing plate 210 cooperate to apply a pressure of 5 to 15 tons to the electrode group, the temperature of the pressure surface of the upper hot pressing plate 220 and the lower hot pressing plate 210 is 85°C to 110°C, and the hot pressing time of the upper hot pressing plate 220 and the lower hot pressing plate 210 to the electrode group is 10 to 300s.

[0047] In some embodiments, the present invention further provides a battery cell, which is a laminated battery cell or a wound battery cell prepared by the battery cell preparation method of the above embodiment. Compared with the prior art, the battery cell preparation method of the present invention saves the hot pressing preheating time of the electrode group, shortens the process time by 50% to 60%, and effectively improves the overall production efficiency of the battery cell.

[0048] The battery cell preparation method of the present invention performs the battery cell manufacturing process in a high temperature environment of 60°C to 70°C, and preheats the positive electrode sheet, the negative electrode sheet and the separator during transportation, so that the electrode group of the positive electrode sheet, the negative electrode sheet and the separator stacked on the processing platform is always at the ideal processing temperature before hot pressing, so that the electrode group on the processing platform is still maintained within the ideal processing temperature range after lamination or winding, so that the hot pressing process can be directly performed to obtain the bare battery cell without separate preheating. It can be seen that the battery cell preparation method effectively improves the fluency of the preparation process, shortens the time required for the hot pressing process in the preparation process, and improves the overall production efficiency of the battery cell. Therefore, the present invention effectively overcomes some practical problems in the prior art and has high utilization value and use significance.

[0049] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for preparing a battery cell, characterized in that: include: In high temperature environment, The positive electrode sheet, the separator and the negative electrode sheet are conveyed to the processing platform by a conveying device, so that the positive electrode sheet, the separator and the negative electrode sheet are stacked into an electrode group on the processing platform; laminating or winding the pole group on the processing platform; Hot pressing and shaping the electrode group to obtain a bare battery cell; Wherein, the ambient temperature of the high temperature environment is 60°C to 70°C.

2. The method for preparing a battery cell according to claim 1, characterized in that: On the conveying path, the positive electrode sheet, the negative electrode sheet and the separator are respectively infrared heated by an infrared heating device.

3. The method for preparing a battery cell according to claim 2, characterized in that: For the positive electrode sheet, infrared heating is performed using infrared light that matches the absorption band of the positive electrode material in the positive electrode sheet; for the negative electrode sheet, infrared heating is performed using infrared light that matches the absorption band of the negative electrode material in the negative electrode sheet.

4. The method for preparing a battery cell according to claim 2, characterized in that: The infrared heating power P of the infrared heating device is 400W to 2000W, and the heating stroke L of the infrared heating device is 0.2m to 0.5m.

5. The method for preparing a battery cell according to claim 4, characterized in that: The heating parameters of the infrared heating device for the positive electrode sheet, the negative electrode sheet and the diaphragm during the conveying process include the infrared heating power P, the heating stroke L and the set temperature rise ΔT. The heating parameters satisfy the relationship: Among them, m is the mass of the heated material, β is the absorption efficiency of the heated material, and v is the transmission speed of the heated material.

6. The method for preparing a battery cell according to claim 1, characterized in that: The electrode group is stacked in the order of the separator, the negative electrode sheet, the separator, and the positive electrode sheet.

7. The method for preparing a battery cell according to claim 1, characterized in that: The step of hot pressing and shaping the electrode group to obtain a bare battery cell comprises: The pole group on the processing platform is hot pressed by hot roller pressing.

8. The method for preparing a battery cell according to claim 1, characterized in that: The step of hot pressing and shaping the electrode group to obtain a bare battery cell comprises: The pole group on the processing platform is hot pressed by pressing an upper hot pressing plate and a lower hot pressing plate, wherein the lower hot pressing plate is arranged on the processing platform, the pole group is arranged on the lower hot pressing plate, and the upper hot pressing plate applies pressure to the pole group above the lower hot pressing plate.

9. The method for preparing a battery cell according to claim 8, characterized in that: The upper hot pressing plate and the lower hot pressing plate cooperate to apply a pressure of 5 to 15 tons to the electrode group. The temperature of the pressure surfaces of the upper hot pressing plate and the lower hot pressing plate is 85° C. to 110° C., and the hot pressing time is 10 to 300 seconds.

10. A battery cell, characterized in that: The battery cell is prepared by the battery cell preparation method according to any one of claims 1 to 9.

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