Method for manufacturing tabbed cells

Abstract

This invention relates to a method for preparing a tab-type battery cell. The method involves winding a positive electrode sheet, a separator, and a negative electrode sheet into a core. Tabs are welded to the positive and negative ends of the core and then flattened. Current collectors are welded to the flattened positive and negative ends of the core. A coating process is then performed, allowing the core to be housed within an insulating film shell. The insulating film shell, along with the core, is then inserted into a steel shell and spot-welded. Electrolyte is filled into the insulating film shell, allowing the tab-type core to be impregnated and permeated by the electrolyte, thus completing the cell preparation. By using a coating process on the tab-type core, the electrolyte can be impregnated and permeated within the insulating film shell, reducing the space required for electrolyte impregnation and permeation, avoiding electrolyte waste, and reducing the time required for the electrolyte to complete the impregnation and permeation process. This improves the preparation efficiency of the cell and battery, and enhances the electrical performance and quality of the cell.

Description

Technical Field

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

[0002] The energy-saving and new energy vehicle industry is developing rapidly, and lithium-ion batteries, as the power source for energy-saving and new energy vehicles, are widely used.

[0003] To achieve lower internal resistance and better power and fast-charging performance, lithium-ion batteries have begun to widely adopt end-face full-tab welding technology. Currently, the end faces of battery cores are mechanically or ultrasonically flattened. After flattening, the core is impregnated with electrolyte within a steel casing. A gap exists between the core's exterior and the inner wall of the steel casing, which is used to inject electrolyte for impregnation. To ensure complete impregnation, this gap must be filled with electrolyte. During injection, the core is impregnated from bottom to top. This structure easily leads to electrolyte waste, especially at the bottom. After the lower part of the core is impregnated, the excess electrolyte becomes ineffective. The larger the gap between the core and the inner wall of the steel casing, the more electrolyte is wasted. Furthermore, to achieve complete impregnation, a larger gap requires more time for electrolyte injection, thus lengthening the entire cell manufacturing process and impacting efficiency. Summary of the Invention

[0004] This invention provides a method for preparing a tab battery cell, which solves the defects in the existing battery cell preparation process of electrolyte impregnation and core winding, which easily leads to electrolyte waste and long impregnation time, affecting the battery cell preparation efficiency, and improves the electrical performance and quality of the battery cell.

[0005] This invention provides a method for preparing a tab battery cell, comprising the following steps:

[0006] Step 1: Wind the positive electrode sheet, separator, and negative electrode sheet into a core to form a core positive terminal and a core negative terminal, and weld tabs to the core positive terminal and the core negative terminal respectively;

[0007] Step 2: Flatten the positive and negative ends of the core.

[0008] Step 3: Weld current collectors to the positive and negative ends of the flattened core to obtain the electrode lug core;

[0009] Step 4: Coat the electrode core with a film so that the electrode core is fitted inside the insulating film shell;

[0010] Step 5: Insert the insulating film shell together with the electrode core into the steel shell, and spot weld the current collector at the negative end of the core and the bottom of the steel shell to complete the cell structure installation;

[0011] Step Six: Fill the insulating film shell with electrolyte, and use the electrolyte to impregnate and permeate the electrode core. Seal the steel shell to complete the preparation of the battery cell.

[0012] According to the method for preparing the electrode core provided by the present invention, the insulating film shell in step four has the same shape as the electrode core. The insulating film shell is open at the top and closed at the bottom, and the lower closed area is provided with a channel for spot welding of the current collector at the negative end of the core and the bottom of the steel shell.

[0013] According to the method for preparing the electrode cell provided by the present invention, the insulating film shell is made of a transparent high-temperature resistant polyester film, and its material is a polyethylene terephthalate plastic.

[0014] According to the method for preparing the electrode cell provided by the present invention, the insulating film shell and the electrode core are cylindrical structures or other structures suitable for the shape of lithium batteries.

[0015] According to the method for preparing the electrode core provided by the present invention, the electrode core is a cylindrical core formed by winding the positive electrode sheet, the diaphragm, and the negative electrode sheet. The insulating film shell is a cylinder with an open upper end and a closed lower end, and a circular hole is provided at the center of the closed lower end to facilitate spot welding of the current collector at the negative end of the core and the bottom of the steel shell.

[0016] According to the method for preparing a tab cell provided by the present invention, the tab in step one is a monopole, bipole, multipole, or all-pole.

[0017] According to the method for preparing the electrode cell provided by the present invention, the positive electrode sheet in step one is made by coating a positive electrode slurry onto an aluminum foil, and the positive electrode slurry is prepared from lithium iron phosphate, ternary materials, lithium manganese oxide, binder and conductive agent.

[0018] According to the method for preparing the electrode cell provided by the present invention, the negative electrode sheet in step one is made by coating a negative electrode paste onto a copper foil, and the negative electrode paste is prepared from graphite material, binder and conductive agent.

[0019] According to the method for preparing the electrode cell provided by the present invention, the separator in step one is a ceramic separator.

[0020] According to the electrode cell preparation method provided by the present invention, the flattening process in step two uses mechanical flattening or ultrasonic flattening to flatten the positive end and the negative end of the core.

[0021] This invention provides a method for preparing a tab cell. By performing a coating process on the tab core, the electrolyte can be impregnated and penetrated within the insulating film shell. This reduces the space required for the electrolyte to penetrate and avoids electrolyte waste. Furthermore, it reduces the time required for the electrolyte to complete the penetration process, thereby improving the preparation efficiency of the cell and battery, and enhancing the electrical performance and quality of the cell. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 This is a schematic flowchart of the method for preparing the electrode cell provided by the present invention;

[0024] Figure 2 This is a schematic diagram of the internal component structure of the steel shell of the electrode cell provided by the present invention;

[0025] Figure 3 This is a schematic diagram of the structure of the electrode core provided by the present invention;

[0026] Figure 4 This is a schematic diagram of the structure of the insulating film shell provided by the present invention;

[0027] Figure label:

[0028] 1. Positive end of the winding core; 2. Negative end of the winding core; 3. Tire of the winding core; 4. Insulating film shell; 5. Round hole. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0030] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0031] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0032] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0033] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0034] One embodiment of the present invention provides a method for preparing a tab battery cell, referring to... Figure 1 As shown, it includes the following steps:

[0035] Step 1: Wind the positive electrode, separator, and negative electrode into a core, such as... Figure 3 As shown, a core positive terminal 1 and a core negative terminal 2 are formed, and tabs are welded to the core positive terminal 1 and the core negative terminal 2 respectively. The tabs can be single tabs, double tabs, multiple tabs, or all tabs. Here, all tabs are selected because the battery cell made with this structure has superior electrical performance and battery quality compared to other tab structures. The positive electrode sheet is made by coating positive electrode paste onto aluminum foil. The positive electrode paste is made of lithium iron phosphate, ternary materials, lithium manganese oxide, binder, and conductive agent. The negative electrode sheet is made by coating negative electrode paste onto copper foil. The negative electrode paste is made of graphite materials, binder, and conductive agent. The separator is a ceramic separator.

[0036] Step 2: Perform a flattening process on the positive end 1 and negative end 2 of the core. The flattening process is carried out by mechanical flattening or ultrasonic flattening to flatten the positive end and negative end of the core.

[0037] Step 3: Weld current collectors to the flattened core positive terminal 1 and core negative terminal 2 to obtain core tab 3.

[0038] Step 4: Coat the tab core 3 with a film so that the tab core 3 is fitted inside the insulating film shell 4.

[0039] Step 5: Refer to Figure 2 As shown, the insulating film shell 4, together with the electrode lug core 3, is installed into the steel shell, and the current collector of the negative end 2 of the core and the bottom of the steel shell are spot welded to complete the installation of the battery cell structure.

[0040] Step Six: Fill the insulating film shell 4 with electrolyte, and use the electrolyte to impregnate and penetrate the electrode core 3. Seal the steel shell to complete the preparation of the battery cell.

[0041] In this embodiment, the electrode core 3 is coated with a film during the manufacturing process, so that the electrode core 3 is fitted inside the insulating film shell 4. The electrolyte is finally injected into the insulating film shell 4. The electrode core 3 and the insulating film shell 4 can be closely fitted. In this way, compared with the traditional method of injecting electrolyte into the gap space between the steel shell and the core, the amount of electrolyte to be injected is much smaller. It is equivalent to completely covering the outer surface of the electrode core 3 with a film, and the film applies pressure to the electrolyte, so that the electrolyte is injected quickly. The electrolyte rapidly penetrates into the tab core 3. Compared to the traditional method of injecting electrolyte into the gap between the steel shell and the core, this embodiment reduces the amount of electrolyte injected and the injection time. Because the membrane covers the tab core 3, the insulating film shell 4 undergoes some deformation and elastic contraction after electrolyte injection, creating pressure on the electrolyte. Under this pressure, the electrolyte rapidly penetrates into the tab core 3, improving the battery cell's electrical performance and quality. Overall, the entire electrolyte penetration process is faster than traditional methods, saving time and improving battery cell manufacturing efficiency.

[0042] This embodiment further describes the insulating film shell 4 based on the above embodiment. In this embodiment, the insulating film shell 4 in step four has the same shape as the electrode lug core 3. (Refer to...) Figure 4 As shown, the insulating film shell 4 is open at the top and closed at the bottom, with a channel in the closed area at the bottom for spot welding of the current collector of the negative terminal 2 of the core and the bottom of the steel shell. The insulating film shell 4 is made of transparent high-temperature resistant polyester film, which is a polyterephthalic acid plastic. The insulating film shell 4 provides space for the subsequent injection of electrolyte to impregnate the tab core 3. The high-temperature resistant polyester film made of polyterephthalic acid plastic has flexible properties, so the insulating film shell 4 is not a rigid shell and has a certain degree of elastic deformation and shrinkage. After the electrolyte is injected into the insulating film shell 4, it expands the insulating film shell 4. Due to its own characteristics, the insulating film shell 4 has a reaction force on the electrolyte, which compresses the electrolyte to impregnate the tab core 3, improving the impregnation efficiency and quickly completing the impregnation of the electrolyte.

[0043] In this embodiment, the insulating film shell 4 and the tab core 3 are cylindrical structures or other structures suitable for lithium battery shapes. Cylindrical structures are common in lithium batteries, but the tab cell fabrication method provided by this invention is also applicable to other lithium battery structures, such as prismatic lithium batteries. This embodiment provides a specific example using a cylindrical cell structure, a method for fabricating a tab cell, comprising the following steps:

[0044] Step 1: Prepare a positive electrode slurry using lithium iron phosphate, ternary materials, lithium manganese oxide, and other main materials, along with binders and conductive agents. Coat the positive electrode slurry onto aluminum foil to fabricate the positive electrode sheet. Prepare a negative electrode slurry using graphite and other main materials, along with binders and conductive agents. Coat the negative electrode slurry onto copper foil to fabricate the negative electrode sheet. Use a commonly used ceramic separator material for the separator. Wind the prepared positive electrode sheet, separator, and negative electrode sheet into a cylindrical core, such as... Figure 3 As shown, a cylindrical core is formed by a positive terminal 1 and a negative terminal 2, and full-pole tabs are welded to the positive terminal 1 and the negative terminal 2, respectively.

[0045] Step 2: Use mechanical flattening to flatten the positive end 1 and negative end 2 of the core. The mechanical flattening process reduces the height of the cylindrical core with the full tab, and also reduces the height of the positive full tab of the positive end 1 and the negative full tab of the negative end 2. It also increases the contact area of ​​each region of the positive full tab of the positive end 1 and the negative full tab of the negative end 2, making the ends flat and facilitating subsequent laser welding of the current collector.

[0046] Step 3: Weld current collectors to the positive end 1 and negative end 2 of the flattened core to obtain a full-tab cylindrical core (tab core 3).

[0047] Step 4: The cylindrical core with all tabs is coated with a film, so that the core 3 with tabs is fitted inside the insulating film shell 4. (Refer to...) Figure 4 As shown, the insulating film shell 4 in this embodiment is a cylinder with an open top and a closed bottom, and a circular hole 5 is provided at the center of the closed bottom end to facilitate the current collection plate of the negative end 2 of the core and the bottom of the steel shell to be spot welded.

[0048] Step 5: Refer to Figure 2 As shown, the insulating film shell 4, together with the electrode core 3, is installed into the steel shell, and the current collector of the negative end 2 of the core and the bottom of the steel shell are spot welded through the round hole 5 of the insulating film shell 4 to complete the installation of the battery cell structure.

[0049] Step Six: Fill the insulating film shell 4 with electrolyte, and use the electrolyte to impregnate and penetrate the electrode core 3. Seal the steel shell to complete the preparation of the battery cell.

[0050] The method for preparing the tab cell in this embodiment adds a coating process for the full-tab cylindrical core, and further impregnates and penetrates the core with electrolyte in the subsequent liquid injection process, thereby improving the electrical performance and quality of the full-tab cylindrical core, increasing the efficiency of impregnation and penetration, quickly completing the impregnation and penetration of electrolyte, reducing the time required for core preparation, and improving work efficiency.

[0051] The electrode cell preparation method provided by this invention can prepare an electrode cell and a battery containing the electrode cell. The electrode cell includes a steel shell, an insulating film shell 4, an electrode core 3, and an electrolyte. The insulating film shell 4 is installed inside the steel shell. The electrode core 3 is installed inside the insulating film shell 4. The positive end 1 and the negative end 2 of the electrode core 3 are respectively provided with full electrodes and welded with current collectors. The current collector of the negative end 2 is welded to the steel shell through the bottom of the insulating film shell 4. The electrolyte is located inside the insulating film shell 4 and is used to impregnate and permeate the electrode core 3.

[0052] The insulating film shell 4 has the same shape as the electrode lug core 3. The insulating film shell 4 is open at the top and closed at the bottom. The lower closed area is provided with a channel for welding the current collector plate of the negative end of the core 2 and the bottom of the steel shell. The insulating film shell 4 is a transparent shell made of polyethylene terephthalate plastic.

[0053] The insulating film shell 4 and the tab core 3 are cylindrical or other structures suitable for lithium batteries. Specifically, the insulating film shell 4 and the tab core 3 adopt a cylindrical structure, and the tab cell can be made into a full-tab cylindrical cell. The tab core 3 is a cylindrical core wound together by winding the positive electrode sheet, the separator, and the negative electrode sheet. The insulating film shell 4 is a cylinder with an open top and a closed bottom, and a circular hole 5 is provided at the center of the closed bottom end to facilitate welding of the current collector 2 of the negative electrode core and the bottom of the steel shell.

[0054] In summary, the electrode core preparation method provided by this invention, through a coating process on the electrode core, allows the electrolyte to wet and penetrate the electrode core within the insulating film shell. This reduces the space required for the electrolyte to wet and penetrate, avoids electrolyte waste, and also reduces the time required for the electrolyte to complete the wet and penetrate process, thereby improving the preparation efficiency of the cell and battery, and enhancing the electrical performance and quality of the cell.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a tab battery cell, characterized in that, Includes the following steps: Step 1: Wind the positive electrode sheet, the separator, and the negative electrode sheet into a core to form a core positive terminal (1) and a core negative terminal (2), and weld tabs to the core positive terminal (1) and the core negative terminal (2) respectively; Step 2: Flatten the positive end (1) and negative end (2) of the core; Step 3: Weld the current collectors to the flattened positive end (1) and negative end (2) of the core respectively to obtain the tab core (3). Step 4: The electrode core (3) is coated so that the electrode core (3) is fitted inside the insulating film shell (4). The insulating film shell (4) has the same shape as the electrode core (3). The electrode core (3) is a cylindrical core. The insulating film shell (4) is a cylinder with an open top and a closed bottom. A circular hole (5) is provided at the center of the closed bottom end to facilitate spot welding of the current collector of the negative end (2) of the core and the bottom of the steel shell. Step 5: Insert the insulating film shell (4) together with the electrode core (3) into the steel shell, and spot weld the current collector of the negative end (2) of the core and the bottom of the steel shell to complete the battery cell structure installation; Step 6: Fill the insulating film shell (4) with electrolyte, and use the electrolyte to impregnate and penetrate the tab core (3), and seal the steel shell to complete the preparation of the battery cell; The insulating film shell (4) is made of a transparent high-temperature resistant polyester film, which is made of polyterephthalic acid plastic.

2. The tab electrode cell production method according to claim 1, wherein The insulating film shell (4) and the tab core (3) are cylindrical structures or other structures suitable for the shape of lithium batteries.

3. The method for preparing the electrode cell according to claim 1, characterized in that, The electrode in step one can be a monopolar, bipolar, multipolar, or all-polar electrode.

4. The method for preparing the electrode cell according to claim 1, characterized in that, The positive electrode sheet in step one is made by coating a positive electrode slurry onto an aluminum foil. The positive electrode slurry is prepared from lithium iron phosphate, ternary materials, lithium manganese oxide, binder, and conductive agent.

5. The method for preparing the electrode cell according to claim 1, characterized in that, The negative electrode sheet in step one is made by coating a negative electrode paste onto a copper foil. The negative electrode paste is prepared from graphite material, binder and conductive agent.

6. The method for preparing the electrode cell according to claim 1, characterized in that, The diaphragm in step one is a ceramic diaphragm.

7. The method for preparing the electrode cell according to claim 1, characterized in that, The flattening process in step two involves using mechanical or ultrasonic flattening to flatten the positive and negative ends of the core.

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