Pole piece assembly, roll core and battery cell

Abstract

The application discloses a pole piece assembly, a roll core and a battery cell, and belongs to the technical field of batteries. The pole piece assembly is used for the roll core, and comprises a current collector and a lead-out tab. The current collector comprises a coating area and a reserved area. The coating area is provided with an active material layer. The reserved area is arranged along the width direction of the current collector and is located at one end of the width direction of the current collector, and is used for forming a full tab. The lead-out tab is separately arranged with the current collector. Along the extension direction of the lead-out tab, the lead-out tab comprises a first section and a second section which are connected with each other. The first section is used for forming a current lead-out end of the battery cell, and the second section is used for being connected with the full tab. Through the combination of the full tab and the split lead-out tab, the manufacturing process is simplified, and the production cost is reduced while the rate performance is improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to an electrode assembly, a winding core, and a battery cell. Background Technology

[0002] In battery cell manufacturing, current is often drawn out using a single tab or double tab. The structure is simple, but the overcurrent capacity of a single tab or double tab battery cell structure is limited, the internal resistance is relatively large, and it is not suitable for high-rate fast charging. The temperature rise is more obvious during charging.

[0003] All-pole tabs have excellent current carrying capacity, low internal resistance, good heat dissipation, and high rate performance. However, all-pole tabs usually require an additional busbar on the end face, and an adapter plate is then connected to the busbar. This adapter plate passes through the through hole on the top cover of the housing to achieve current extraction, making the manufacturing process relatively complex. Utility Model Content

[0004] This application provides an electrode assembly, a winding core, and a battery cell, which improves rate performance while simplifying the manufacturing process and reducing production costs, thereby at least partially solving the aforementioned technical problems.

[0005] To achieve the above objectives, according to a first aspect of this application, an electrode assembly for a winding core is provided, comprising: The current collector includes a coating area and a reserved area. The coating area is provided with an active material layer. The reserved area and the coating area are arranged along the width direction of the current collector, and the reserved area is located at one end of the width direction of the current collector to form a full tab. The lead-out tab is separately disposed from the current collector. Along the extension direction of the lead-out tab, the lead-out tab includes a first section and a second section that are connected to each other. The first section is used to form the current lead-out terminal of the battery cell, and the second section is used to connect with the full tab.

[0006] Optionally, the current collector further includes a connecting region, which is arranged along the length of the current collector and the coating region, and the connecting region is located at one end of the length of the current collector; The lead-out tab also includes a third segment, and the first segment, the second segment and the third segment are connected in sequence, with the third segment connected to the connection area.

[0007] Optionally, the active material layer has a notch on the side facing the reserved area, so that the current collector and the part corresponding to the notch form a connection area; The lead-out tab also includes a third segment, and the first segment, the second segment and the third segment are connected in sequence, with the third segment connected to the connection area.

[0008] Optionally, the lead-out tab extends along the width direction of the current collector, and the first segment is located on the side of the reserved area away from the coating area.

[0009] Optionally, the third segment is welded to the connection area.

[0010] According to a second aspect of this application, a core is provided, comprising a diaphragm stacked thereon and two electrode assemblies, the diaphragm being located between the two electrode assemblies, the diaphragm and the two electrode assemblies being wound to form the core, the two electrode assemblies having different polarities, and at least one of the two electrode assemblies being the aforementioned electrode assembly.

[0011] Optionally, the second segment extends radially along the core.

[0012] Optionally, the second segment has a radial dimension greater than or equal to the radius of the core.

[0013] According to a third aspect of this application, a battery cell is also provided, including a housing and a winding core encapsulated within the housing, the winding core including the winding core described above.

[0014] Optionally, the housing has a through hole, the first section passes through the through hole, and the battery cell further includes insulating adhesive disposed between the first section and the wall of the through hole.

[0015] In the electrode assembly of this application embodiment, by setting a reserved area on the current collector for forming a full tab and using a separately configured lead-out tab connected to the full tab, a large cross-section current conduction is achieved, which significantly reduces the internal resistance of the cell and improves the rate performance. At the same time, the lead-out tab has both current collection and external lead-out functions, eliminating the need for additional busbars and adapters, simplifying the structure, reducing the number of parts and processes, lowering manufacturing costs, and being compatible with existing soft-pack cell production processes. In summary, by combining the full tab with the separate lead-out tab, the rate performance is improved while the manufacturing process is simplified and production costs are reduced.

[0016] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings, wherein the same reference numerals in the following description denote the same parts.

[0018] Figure 1 This is a schematic diagram of the electrode assembly provided in an exemplary embodiment of this disclosure on one side; Figure 2 yes Figure 1 The diagram shows the structure of the electrode assembly on the other side; Figure 3 This is a schematic diagram of the electrode assembly provided in another embodiment of this disclosure on one side; Figure 4 yes Figure 3 The diagram shows the structure of the electrode assembly on the other side; Figure 5 This is a schematic diagram of the electrode assembly provided in another embodiment of the present disclosure on one side; Figure 6 yes Figure 5 The diagram shows the structure of the electrode assembly on the other side; Figure 7 This is a schematic diagram of the structure of the winding core provided in an exemplary embodiment of this disclosure in the state where full tabs are not formed; Figure 8 yes Figure 7 The diagram shows the end of the core after the full tab is formed, where one end connects to the second section of the lead-out tab. Figure 9 yes Figure 7 The diagram shows the end of the core after the full tab is formed, where the other end connects to the second section of the lead-out tab.

[0019] Explanation of reference numerals in the attached figures: 100. Core; 10. Electrode assembly; 1. Current collector; 11. Coating area; 111. Active material layer; 112. Notch; 121. Reserved area; 122. Connection area; 2. Lead-out tab; 21. First section; 22. Second section; 23. Third section; 101. All tabs; 20. Insulating adhesive. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the protection scope of this application.

[0021] Please see Figure 1 and Figure 2This application provides an electrode assembly 10, which includes a current collector 1 and a lead-out tab 2. The current collector 1 includes a coating area 11 and a reserved area 121. The coating area 11 is provided with an active material layer 111. The reserved area 121 and the coating area 11 are arranged along the width direction (vertical direction in the figure) of the current collector 1, and the reserved area 121 is located at one end of the width direction of the current collector 1 to form a full tab 101 (see figure). Figures 7 to 9 The lead-out tab 2 and the current collector 1 are separately arranged. Along the extension direction of the lead-out tab 2, the lead-out tab 2 includes a first section 21 and a second section 22 that are connected to each other. The first section 21 is used to form the current lead-out terminal of the battery cell, and the second section 22 is used to connect with the full tab 101.

[0022] The technical solution of this application achieves large-section current conduction by setting a reserved area 121 on the current collector 1 for forming the full tab 101 and connecting the split lead-out tab 2 to the full tab 101, which significantly reduces the internal resistance of the cell and improves the rate performance. At the same time, the lead-out tab 2 has both current collection and external lead-out functions, eliminating the need for additional busbars and adapters, simplifying the structure, reducing the number of parts and processes, and lowering the manufacturing cost. It is also compatible with existing soft-pack cell production processes. In summary, by combining the full tab 101 with the split lead-out tab 2, the rate performance is improved while the manufacturing process is simplified and the production cost is reduced.

[0023] Understandably, the reserved area 121 can be an uncoated area that extends continuously along the length of the current collector 1 (see...). Figure 1 and Figure 2 After the electrode assembly 10 is wound, it is flattened and compacted through a rolling (also known as "pressing") process to form a full tab 101 structure integrally formed with the current collector 1; the reserved area 121 can also be multiple uncoated areas discontinuously (discretely) distributed along the length direction (see Figure 3 and Figure 4 After winding, the discrete foil sections are bent, stacked, and compacted towards the same side through a flattening (also known as "flattening") process, forming a conductive path and creating a full tab 101 structure. Based on this, this solution connects the second segment 22 of the lead-out tab 2 to the full tab 101, thus eliminating the need for traditional external busbars and adapters and achieving low-resistance current output.

[0024] Please see Figure 1 and Figure 2 ,or Figure 3 and Figure 4In some embodiments, the current collector 1 further includes a connecting region 122, which is arranged along the length direction of the current collector 1 (the left-right direction in the figures, i.e., the winding direction of the electrode assembly 10) and is located at one end of the current collector 1 along its length. The lead-out tab 2 further includes a third segment 23, with the first segment 21, the second segment 22, and the third segment 23 connected sequentially, and the third segment 23 connected to the connecting region 122. In these embodiments, the lead-out tab 2 can be connected to the connecting region 122 of the current collector 1 before winding via the third segment 23, so that the electrode and the lead-out tab 2 form an integral structure, which facilitates automated conveying and assembly and improves production efficiency. At the same time, the connection between the third segment 23 and the connecting region 122 enhances the mechanical connection strength and current conduction area between the lead-out tab 2 and the current collector 1, which is beneficial to improving the reliability of current extraction. In addition, the connecting area 122 is located at one end of the current collector 1 along its length, so that the coating area 11 remains continuous, the coating head does not need to be raised or lowered to avoid obstacles, the coating process is stable, and it is beneficial to ensure the uniformity of the active material layer 111 and the production yield.

[0025] Please see Figure 5 and Figure 6 In some embodiments, the active material layer 111 has a notch 112 on the side facing the reserved area 121, so that the current collector 1 and the portion corresponding to the notch 112 form a connection area 122; the lead tab 2 also includes a third segment 23, with the first segment 21, the second segment 22 and the third segment 23 connected in sequence, and the third segment 23 connected to the connection area 122. In these embodiments, the lead tab 2 can be connected to the area of ​​the current collector 1 exposed by the notch 112 before winding through the third segment 23, realizing the pre-integration of the electrode assembly 10, which facilitates overall handling and alignment, and reduces subsequent assembly deviations; this connection method also increases the connection area and bonding strength between the lead tab 2 and the current collector 1, which helps to reduce contact resistance, improve overcurrent capacity and long-term stability. At the same time, the connection area 122 is located at the notch 112 of the active material layer 111, so that the connection position of the lead tab 2 can be flexibly designed according to the cell packaging requirements, and can be accurately located in a preset position after winding, which facilitates reliable connection with external circuits.

[0026] Please see Figure 1 and Figure 2 ,or Figure 3 and Figure 4 ,or Figure 5 and Figure 6In some embodiments, the lead-out tab 2 extends along the width direction of the current collector 1, with the first segment 21 located on the side of the reserved area 121 away from the coating area 11. In these embodiments, the lead-out tab 2 extends along the width direction of the current collector 1, and its extension direction is perpendicular to the winding direction of the electrode assembly 10 (the length direction of the current collector 1). This can effectively reduce the stress and deformation experienced by the lead-out tab 2 during the winding process, reduce the impact on winding accuracy, and help improve the neatness and consistency of the internal structure of the battery cell. The first segment 21 is located on the side of the reserved area 121 away from the coating area 11, that is, it extends outward after winding is completed. At this time, the reserved area 121 is flattened or bent to form a full tab 101. The second segment 22 and the third segment 23 are located in the exposed area of ​​the end face of the core 100, which facilitates the subsequent welding connection of the second segment 22 to the full tab 101, and allows the first segment 21 to be directly used as a current lead-out terminal, realizing reliable electrical connection and encapsulation.

[0027] Please see Figure 1 Or or Figure 5 In some embodiments, the third segment 23 is welded to the connection area 122. In these embodiments, the third segment 23 is welded to the connection area 122 by means of welding, such as ultrasonic welding, laser welding, spot welding, or multi-point continuous welding, to achieve good electrical conductivity and mechanical strength.

[0028] In other embodiments, the third segment 23 and the connecting area 122 can also be mechanically fixed and electrically connected by means of crimping, conductive adhesive bonding, etc.

[0029] It should be noted that only the coated area 11 of the current collector 1 has an active material layer 111, while the remaining areas are uncoated, exposing the metal surface of the current collector 1 itself. These uncoated areas do not participate in the electrochemical reaction but possess good conductivity and solderability. Therefore, the uncoated areas of the current collector 1 can be used to form the reserved area 121 of the full tab 101, or as the connection position of the lead-out tab 2, to meet conductivity requirements.

[0030] Please see Figures 7 to 9 According to a second aspect of this disclosure, a core 100 is provided, comprising a diaphragm stacked thereon and two electrode assemblies 10, the diaphragm being located between the two electrode assemblies 10, the diaphragm and the two electrode assemblies 10 being wound together to form the core 100, the two electrode assemblies 10 having different polarities, and at least one of the two electrode assemblies 10 being the aforementioned electrode assembly 10. This core 100 possesses all the beneficial effects of the aforementioned electrode assembly 10, which will not be elaborated further in this disclosure.

[0031] Understandably, the two electrode assemblies 10 are a positive electrode assembly 10 and a negative electrode assembly 10, respectively. The current collector 1 of the positive electrode assembly 10 is divided into a positive electrode coating area 11 and a positive electrode pre-reserved area 121, with the positive electrode coating area 11 coated with a positive active material layer 111. Similarly, the current collector 1 of the negative electrode assembly 10 is divided into a negative electrode coating area 11 and a negative electrode pre-reserved area 121, with the negative electrode coating area 11 coated with a negative active material layer 111. In the core 100 structure, the positive electrode coating area 11 and the negative electrode coating area 11 are positioned opposite each other, with a diaphragm sandwiched between them for electrical insulation. After winding, the positive electrode pre-reserved area 121 and the negative electrode pre-reserved area 121 are located at opposite axial ends of the core 100. Through a flattening (or bending) process, the positive electrode pre-reserved area 121 forms a positive electrode tab 101, and the negative electrode pre-reserved area 121 forms a negative electrode tab 101. In this disclosure, the positive omnipolar tab 101 achieves current extraction through the second segment 22 and the first segment 21 of the lead-out tab 2. Similarly, the negative omnipolar tab 101 can also be connected to another lead-out tab 2, thereby achieving efficient current conduction at the bipolar tab end without the need for a busbar.

[0032] Please see Figure 8 or Figure 9 In some embodiments, the second segment 22 extends radially along the core 100. In these embodiments, "radial" refers to the direction from the center of the core 100 to the outer edge, and is applicable to core 100 structures with any cross-sectional shape such as circular, elliptical, or polygonal, and is not limited to a strictly cylindrical shape. By extending the second segment 22 radially, the multiple layers of tabs 101 inside the core 100 can be connected via the shortest path, reducing current transmission distance, lowering local resistance, and improving current distribution uniformity.

[0033] Please see Figure 8 or Figure 9 In some embodiments, the radial dimension of the second segment 22 of the core 100 is greater than or equal to the radius of the core 100. In these embodiments, the second segment 22 can cover the entire range from the edge to the center of the core 100, so that each layer of full tab 101 can be directly or indirectly connected to the second segment 22, thereby effectively collecting the current on the entire end face and improving the current conduction capability.

[0034] Please see Figure 9 In some examples, the second segment 22 is arranged along the entire diameter of the core 100. In these embodiments, "diameter" generally refers to the straight line direction passing through the center of the core 100 and connecting the two side edges, and is not limited to a cylindrical structure. When the second segment 22 is arranged along the entire diameter, it can be connected to the tab 101 at multiple locations on the end face of the core 100 (such as the two ends of each layer) to form a double-sided flow path, further reducing the overall internal resistance.

[0035] In some embodiments, the second segment 22 extends from the edge of the core 100, bends towards the central axis, crosses the radius, and then extends from near the central axis. In other embodiments, the second segment 22 extends from one side edge, crosses the entire diameter, and then extends from the opposite side edge. In still other embodiments, the second segment 22 extends from the middle of the core 100, extends radially for a distance, folds back, and finally extends from a preset position. The bending form of the second segment 22 can be flexibly designed according to the connection position of the third segment 23 and the current collector 1, as well as the required extension direction of the first segment 21. While ensuring a reliable connection with the tab 101, it adapts to different packaging requirements and external circuit layouts, improving assembly freedom and process compatibility.

[0036] According to a third aspect of this disclosure, a battery cell is provided, the battery cell including a housing and a winding core 100 encapsulated within the housing, the winding core 100 including the aforementioned winding core 100, the battery cell having all the beneficial effects of the aforementioned winding core 100, which will not be repeated here.

[0037] In some embodiments, the housing has a through hole, through which the first segment 21 passes. The battery cell also includes an insulating adhesive 20 disposed between the first segment 21 and the wall of the through hole. In these embodiments, the insulating adhesive 20 provides electrical isolation and sealing between the first segment 21 and the housing, preventing short circuits and improving battery cell safety, while allowing the first segment 21 to be stably led out for easy external connection.

[0038] In some embodiments, the insulating adhesive 20 is one of thermosetting resin, silicone or epoxy adhesive, which has good insulation properties, bonding strength and temperature resistance, can reliably fix the position of the first segment 21 during the encapsulation process and adapt to the use requirements of the battery cell under different operating conditions.

[0039] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0040] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0041] The embodiments, implementation methods, and related technical features of this application can be combined and substituted for each other without conflict.

[0042] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. An electrode assembly for a wound core, characterized in that, include: The current collector includes a coating area and a reserved area. The coating area is provided with an active material layer. The reserved area and the coating area are arranged along the width direction of the current collector, and the reserved area is located at one end of the width direction of the current collector to form a full tab. The lead-out tab is separately disposed from the current collector. Along the extension direction of the lead-out tab, the lead-out tab includes a first section and a second section that are connected to each other. The first section is used to form the current lead-out terminal of the battery cell, and the second section is used to connect with the full tab.

2. The electrode assembly according to claim 1, characterized in that, The current collector further includes a connecting region, which is arranged along the length of the current collector and the coating region, and the connecting region is located at one end of the length of the current collector. The lead-out tab also includes a third segment, and the first segment, the second segment and the third segment are connected in sequence, with the third segment connected to the connection area.

3. The electrode assembly according to claim 1, characterized in that, The active material layer has a notch on the side facing the reserved area, so that the current collector and the part corresponding to the notch form a connection area; The lead-out tab also includes a third segment, and the first segment, the second segment and the third segment are connected in sequence, with the third segment connected to the connection area.

4. The electrode assembly according to claim 2 or 3, characterized in that, The lead-out tab extends along the width direction of the current collector, and the first segment is located on the side of the reserved area away from the coating area.

5. The electrode assembly according to claim 2 or 3, characterized in that, The third segment is welded to the connection area.

6. A type of winding core, characterized in that, The device includes a diaphragm stacked on top of each other and two electrode assemblies, the diaphragm being located between the two electrode assemblies, the diaphragm and the two electrode assemblies being wound together to form the core, the two electrode assemblies having different polarities, and at least one of the two electrode assemblies being an electrode assembly as described in any one of claims 1 to 5.

7. The winding core according to claim 6, characterized in that, The second segment extends radially along the core.

8. The winding core according to claim 7, characterized in that, The second segment has a radial dimension greater than or equal to the radius of the core.

9. A battery cell, characterized in that, It includes a housing and a core encapsulated within the housing, the core comprising the core as described in any one of claims 6 to 8.

10. The battery cell as described in claim 9, characterized in that, The housing has a through hole, the first section passes through the through hole, and the battery cell also includes insulating adhesive disposed between the first section and the wall of the through hole.

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