Roll core and battery

Abstract

The utility model provides a roll core and a battery, the roll core comprises a first pole piece, a second pole piece and a diaphragm which are wound and stacked, the polarity of the first pole piece is opposite to that of the second pole piece, and the diaphragm is arranged between the first pole piece and the second pole piece; the first pole piece comprises a first winding head end and a first winding tail end, the second pole piece comprises a second winding head end and a second winding tail end, and the second winding tail end is located on the inner side of the first pole piece; wherein the first pole piece comprises an outer side surface positioned on the outer side of the first pole piece, and the outer side surface comprises an uncoated section extending from the first winding tail end to the first winding head end. According to the embodiment of the invention, the second winding tail end of the second pole piece of the winding core is positioned on the inner side of the first pole piece, and the outer side surface of the first pole piece comprises the uncoated section extending from the first winding tail end to the first winding head end, so that the thickness of the first pole piece close to the first winding tail end is reduced without influencing the performance of the winding core; the volume of the roll core is reduced, and the energy density of the roll core is improved, so that the energy density of the battery is improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to a winding core and a battery. Background Technology

[0002] A battery core is typically formed by winding a negative electrode layer, a separator layer, a positive electrode layer, and a separator layer together. The surfaces of the positive and negative electrodes are coated with active coatings to improve battery performance. In related technologies, active coatings are usually applied to both sides of the positive and negative electrodes. However, when the positive and negative electrodes and separator are wound together to form a core, an ineffective active coating layer forms radially outwards on the core. This ineffective active coating does not significantly improve battery performance; instead, it increases the core's volume, thus affecting the battery's energy density. Utility Model Content

[0003] The embodiments of this application provide a winding core and a battery that can improve the technical problem of forming an ineffective active coating on the radial outer side of the winding core, which leads to an increase in the volume of the winding core and thus affects the energy density of the battery.

[0004] In a first aspect, embodiments of this application provide a winding core, the winding core including a first electrode sheet, a second electrode sheet, and a diaphragm wound and stacked, the first electrode sheet and the second electrode sheet having opposite polarities, and the diaphragm being disposed between the first electrode sheet and the second electrode sheet; the first electrode sheet includes a first winding start end and a first winding end end, the second electrode sheet includes a second winding start end and a second winding end end, the second winding end end being located inside the first electrode sheet;

[0005] The first electrode includes an outer surface located on its outer side, the outer surface including an uncoated section extending from the tail end of the first winding to the head end of the first winding.

[0006] In one embodiment, the length of the uncoated segment is less than or equal to the outer perimeter length of the core.

[0007] In one embodiment, the length of the uncoated segment is greater than or equal to 10 mm and less than or equal to 300 mm.

[0008] In one embodiment, the first electrode is a positive electrode or a negative electrode.

[0009] In one embodiment, the outer surface further includes a coated section extending from the uncoated section toward the first winding head end, the coated section being coated with an active coating;

[0010] The core also includes a protective layer that covers the junction between the coated section and the uncoated section.

[0011] In one embodiment, a portion of the diaphragm covers the uncoated segment.

[0012] In one embodiment, a first tab is welded to the first winding end of the first electrode sheet, and the first tab extends along the length direction of the first electrode sheet; a second tab is welded to the second winding end of the second electrode sheet, and the second tab extends along the length direction of the second electrode sheet; the first tab and the second tab are spaced apart along the width direction of the first electrode sheet.

[0013] In one embodiment, the first electrode includes an inner side opposite to the outer side, the inner side including a welded section extending from the tail end of the first winding to the head end of the first winding, the welded section being welded to the first electrode tab, and the length of the welded section being less than the length of the uncoated section.

[0014] In one embodiment, the core extends along a curved segment, and the first tab and the second tab are located at one end of the core's extension direction. The plane containing the curved segment is perpendicular to the width direction of the first electrode sheet.

[0015] Secondly, embodiments of this application provide a battery, comprising:

[0016] The housing has a mounting cavity;

[0017] The core, as described above, is installed within the mounting cavity. The core includes a first electrode, a second electrode, and a diaphragm wound and stacked together. The first and second electrode have opposite polarities, and the diaphragm is disposed between the first and second electrode. The first electrode includes a first winding start end and a first winding end, and the second electrode includes a second winding start end and a second winding end, with the second winding end located inside the first electrode.

[0018] The first electrode includes an outer surface located on its outer side, the outer surface including an uncoated section extending from the tail end of the first winding to the head end of the first winding.

[0019] The beneficial effects of the embodiments of this application are as follows:

[0020] The core provided in this application embodiment, by placing the second winding tail end of the second electrode sheet inside the first electrode sheet and including an uncoated section extending from the first winding tail end to the first winding head end on the outer surface of the first electrode sheet, can reduce the thickness of a section of the first electrode sheet near the first winding tail end without affecting the core's electrical performance, thereby reducing the overall outer diameter of the core. This reduces the overall volume of the core without changing its electrical charge, thereby increasing the core's energy density.

[0021] The battery provided in this application embodiment, by placing the second winding tail end of the second electrode sheet of the core inside the first electrode sheet, and by including an uncoated section extending from the first winding tail end to the first winding head end on the outer surface of the first electrode sheet, can reduce the thickness of a section of the first electrode sheet near the first winding tail end without affecting the electrical performance of the core, thereby reducing the overall outer diameter of the core. This reduces the overall volume of the core without changing the core's charge capacity, thereby increasing the core's energy density and ultimately improving the battery's energy density. Attached Figure Description

[0022] 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 accompanying 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.

[0023] Figure 1 A top view of one embodiment of the winding core provided for embodiments of this application;

[0024] Figure 2 A front view of one embodiment of the winding core provided for embodiments of this application;

[0025] Figure 3 A top view of one embodiment of the first electrode provided for an embodiment of this application;

[0026] Figure 4 A cross-sectional view of the first electrode provided in an embodiment of this application, which is cross-sectional along the length of the first electrode;

[0027] Figure 5 A top view of the internal structure of an embodiment of a battery provided for an embodiment of this application.

[0028] Battery 100; casing 110; mounting cavity 1101; core 120; first electrode 121; first winding start end 1211; first winding end 1212; outer side 1213; uncoated section 1214; coated section 1215; inner side 1216; welded section 1217; second electrode 122; second winding start end 1221; second winding end 1222; separator 123; protective layer 124; active coating 125; first tab 126; second tab 127; straight section L; curved section S; length direction X; width direction Y. Detailed Implementation

[0029] 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 the embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. In addition, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application. In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in actual use or operation, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device.

[0030] A battery core is typically formed by winding a negative electrode layer, a separator layer, a positive electrode layer, and a separator layer together. The surfaces of the positive and negative electrodes are coated with active coatings to improve battery performance. In related technologies, active coatings are usually applied to both sides of the positive and negative electrodes. However, when the positive and negative electrodes and separator are wound together to form a core, an ineffective active coating layer forms radially outwards on the core. This ineffective active coating does not significantly improve battery performance; instead, it increases the core's volume, thus affecting the battery's energy density.

[0031] To address the aforementioned issues, embodiments of this application provide a winding core and a battery.

[0032] Figure 1 A top view of one embodiment of the winding core provided for embodiments of this application. (See attached image.) Figure 1 As shown, the core 120 includes a first electrode 121, a second electrode 122, and a diaphragm 123 wound and stacked. The first electrode 121 and the second electrode 122 have opposite polarities, and the diaphragm 123 is disposed between the first electrode 121 and the second electrode 122. The first electrode 121 can be a positive electrode and the second electrode 122 a negative electrode, or vice versa. Furthermore, there are two diaphragms 123. The core 120 is formed by winding the first electrode 121, diaphragm 123, second electrode 122, and diaphragm 123 using a winding needle.

[0033] Continue to refer to Figure 1 The first electrode 121 includes a first winding start end 1211 and a first winding end end 1212, which are located at opposite ends of the first electrode 121 in the length direction X. The first electrode 121 is wound starting from the first winding start end 1211 and ending at the first winding end end 1212.

[0034] The second electrode 122 includes a second winding start end 1221 and a second winding end end 1222, which are located at opposite ends of the second electrode 122 in the length direction X. The second electrode 122 is wound starting from the second winding start end 1221 and ending at the second winding end end 1222.

[0035] The second winding tail end 1222 of the second pole piece 122 is located inside the first pole piece 121. It should be noted that the inner side of the first pole piece 121 is the side of the first pole piece 121 facing the center of the core 120 or facing the winding needle (not shown in the figure), and the outer side of the first pole piece 121 is the side of the first pole piece 121 away from the center of the core 120 or away from the winding needle (not shown in the figure).

[0036] In some embodiments, such as Figure 4 As shown, the first electrode 121 includes an outer surface 1213 located on its outer side, the outer surface 1213 including an uncoated section 1214 extending from the first winding tail end 1212 to the first winding head end 1211. It should be noted that the uncoated section 1214 of the outer surface 1213 of the first electrode 121 refers to the section of the outer surface 1213 of the first electrode 121 that is not coated with the active coating 125.

[0037] The winding core 120 provided in this application embodiment, by placing the second winding tail end 1222 of the second electrode 122 inside the first electrode 121 and making the outer surface 1213 of the first electrode 121 include an uncoated section 1214 extending from the first winding tail end 1212 to the first winding head end 1211, can reduce the thickness of a section of the first electrode 121 near the first winding tail end 1212 without affecting the electrical performance of the winding core 120, thereby reducing the overall outer diameter of the winding core 120. While not changing the charge of the winding core 120, it reduces the overall volume of the winding core 120, thereby increasing the energy density of the winding core 120 and thus increasing the energy density of the battery 100.

[0038] In some embodiments, the length of the uncoated segment 1214 of the first electrode 121 can be less than or equal to the outer perimeter length of the core 120. This avoids the uncoated segment 1214 of the first electrode 121 being too long and affecting the electrical performance of the core 120.

[0039] Specifically, the ratio of the length of the uncoated section 1214 of the first electrode 121 to the outer perimeter length of the core 120 can be greater than or equal to 0.5 and less than or equal to 1, so as to minimize the overall volume of the core 120 while ensuring the electrical performance of the core 120.

[0040] In some embodiments, the length of the uncoated segment 1214 of the first electrode 121 can be greater than or equal to 10 mm to minimize the overall volume of the core 120. The length of the uncoated segment 1214 of the first electrode 121 can be 50 mm, 100 mm, 150 mm, 200 mm, etc., depending on the structure and size of the core 120.

[0041] Additionally, the uncoated section 1214 of the first electrode 121 can be less than or equal to 300 mm to avoid excessive length of the uncoated section 1214, which could affect the electrical performance of the core 120. The length of the uncoated section 1214 of the first electrode 121 can be 70 mm, 120 mm, 180 mm, 250 mm, etc., depending on the structure and dimensions of the core 120.

[0042] In some preferred embodiments, the length of the uncoated segment 1214 of the first electrode 121 can be greater than or equal to 10 mm and less than or equal to 300 mm, so that the cell achieves a good balance in terms of overall volume and electrical performance.

[0043] In some embodiments, such as Figure 4 As shown, the outer surface 1213 of the first electrode 121 may also include a coated section 1215, which extends from the uncoated section 1214 to the first winding head end 1211. The coated section 1215 is coated with an active coating 125 to improve the electrical performance of the first electrode 121.

[0044] Specifically, the coated section 1215 of the first electrode 121 extends from the uncoated section 1214 away from the first winding tail end 1212 toward the first winding head end 1211. After the first electrode 121, the second electrode 122 and the diaphragm 123 are wound to form the core 120, the coated section 1215 of the first electrode 121 is positioned opposite to the inner surface 1216 of the second electrode 122.

[0045] In some embodiments, such as Figure 3 and Figure 4 As shown, the core 120 may also include a protective layer 124, which covers the junction of the coated section 1215 and the uncoated section 1214 to protect the active coating 125 applied to the coated section 1215 and reduce the risk of the active coating 125 falling off.

[0046] Specifically, the protective layer 124 includes adhesive tape. A portion of the protective layer 124 away from the first winding tail end 1212 of the first electrode 121 covers the active coating 125 applied to the coated section 1215, and another portion of the protective layer 124 near the first winding tail end 1212 of the first electrode 121 covers the uncoated section 1214.

[0047] In other embodiments, adhesive can be applied at the junction of the coated section 1215 and the uncoated section 1214, and a protective layer 124 can be formed after the adhesive solidifies, so as to reduce the risk of the active coating 125 falling off.

[0048] In some embodiments, the coated segment 1215 of the first electrode 121 can be kept at a certain distance from the first winding start end 1211 of the first electrode 121, so that the end of the coated segment 1215 away from the first winding end 1212 of the first electrode 121 can be more stably held on the first electrode 121. Specifically, a protective layer 124 can be covered on the end of the coated segment 1215 away from the first winding end 1212 of the first electrode 121, to reduce the risk of the coated segment 1215 detaching from the first winding end 1212 of the first electrode 121.

[0049] In some embodiments, such as Figure 1 As shown, a portion of the separator 123 can cover the uncoated section 1214 of the first electrode 121, thereby separating the uncoated section 1214 of the first electrode 121 from the casing of the battery 100.

[0050] Specifically, one of the two diaphragms 123 of the core 120 can be extended to the outside of the uncoated section 1214 of the first electrode 121, and the first winding tail end 1212 of the first electrode 121 can be located inside the diaphragm 123, so that the diaphragm 123 covers the uncoated section 1214 of the first electrode 121.

[0051] In other embodiments, instead of covering the uncoated section 1214 of the first electrode 121 with the diaphragm 123, an insulating layer may be provided on the outside of the uncoated section 1214 of the first electrode 121 to keep the uncoated section 1214 of the first electrode 121 insulated from the inner surface of the housing.

[0052] Specifically, the protective layer 124 can be extended along the length direction X of the first electrode 121 to the first winding tail end 1212 of the first electrode 121, so that the protective layer 124 covers the uncoated section 1214 of the first electrode 121, and keeps the uncoated section 1214 of the first electrode 121 insulated from the inner surface of the outer casing 110.

[0053] like Figures 1 to 4 As shown, the winding core 120 also includes a first tab 126 and a second tab 127. The first tab 126 is connected to the first electrode 121, and the second tab 127 is connected to the second electrode 122. The first tab 126 and the second tab 127 are respectively used to connect to the two terminals (not shown in the figure) of the battery 100 with opposite polarities.

[0054] The first electrode tab 126 can extend at an angle to the length direction X of the first electrode plate 121, or it can extend along the length direction X of the first electrode plate 121. Alternatively, the first electrode tab 126 can be connected to the first winding start end 1211 and the first winding end end 1212 of the first electrode plate 121, or it can be connected to a portion between the first winding start end 1211 and the first winding end end 1212.

[0055] Similarly, the extension direction of the second tab 127 can be at an angle to the length direction X of the second pole piece 122, or the second tab 127 can extend along the length direction X of the second pole piece 122. Furthermore, the second tab 127 can be connected to the second winding start end 1221 and the second winding tail end 1222 of the second pole piece 122, or the second tab 127 can be connected to a portion between the second winding start end 1221 and the second winding tail end 1222.

[0056] In some embodiments, such as Figures 1 to 4 As shown, a first tab 126 can be welded to the first winding tail end 1212 of the first electrode 121, and the first tab 126 extends along the length direction X of the first electrode 121. Simultaneously, a second tab 127 is welded to the second winding tail end 1222 of the second electrode 122, and the second tab 127 extends along the length direction X of the second electrode 122. Furthermore, the first tab 126 and the second tab 127 are spaced apart along the width direction Y of the first electrode 121. Therefore, the positive and negative terminals of the battery 100 can be located at one end of the first electrode 121 in the length direction X of the winding core 120, reducing the internal space occupied by the first tab 126 and the second tab 127 in the battery 100's casing 110, which is beneficial for improving the energy density of the battery 100.

[0057] It is understandable that, in order to facilitate the connection of the first tab 126 and the second tab 127 with their corresponding pole posts, a certain distance needs to be maintained between the side of the core 120 with the first tab 126 and the second tab 127 and the inner surface of the outer casing 110. If the extension direction of the first tab 126 forms an angle with the length direction X of the first pole piece 121, and the extension direction of the second tab 127 forms an angle with the length direction X of the second pole piece 122, then the first tab 126 and the second pole piece 122 will extend from the core 120 along the width direction Y of the first pole piece 121 or the second pole piece 122. Therefore, a certain distance needs to be maintained between the core 120 and the outer casing 110 along the width direction of the first pole piece 121 or the second pole piece 122. Since the length of the core 120 along the extension direction of the first pole piece 121 or the second pole piece 122 is relatively long, the formation of this distance will result in a large space between the outer casing 110 and the core 120, thereby increasing the volume of the outer casing 110.

[0058] In this embodiment, a first tab 126 is welded to the first winding tail end 1212 of the first electrode 121, and the first tab 126 extends along the length direction X of the first electrode 121. Simultaneously, a second tab 127 is welded to the second winding tail end 1222 of the second electrode 122, and the second tab 127 extends along the length direction X of the second electrode 122. With this configuration, the first tab 126 and the second tab 127 of the core 120 extend from one end of the core 120 along the length direction X of the first electrode 121 or the second electrode 122. Therefore, a certain distance needs to be maintained between the core 120 and the outer casing 110 on one side along the length direction X of the first electrode 121 or the second electrode 122. Since the core 120 has a smaller dimension along the width direction Y of the first electrode 121 and the second electrode 122, the formation of this spacing results in a larger space between the casing 110 and the core 120, thereby reducing the volume of the casing 110 and increasing the energy density of the battery 100.

[0059] In some embodiments, such as Figure 4 As shown, the first electrode 121 includes an inner side 1216 opposite to the outer side 1213. The inner side 1216 of the first electrode 121 may include a welding section 1217 extending from the first winding tail end 1212 to the first winding head end 1211. This welding section 1217 is welded to the first electrode tab 126, thereby connecting the first electrode tab 126 to the first electrode 121. The length of the welding section 1217 is less than the length of the uncoated section 1214, in order to increase the area of ​​the inner side 1216 of the first electrode 121 for protruding the active coating 125, thus ensuring the electrical performance of the core 120.

[0060] Specifically, the inner surface 1216 of the first electrode 121 includes a coating segment 1215 that extends from the end of the welding segment 1217 away from the first winding tail end 1212 toward the first winding head end 1211.

[0061] In some embodiments, such as Figure 1 As shown, the core 120 can be extended along the straight segment L. Alternatively, in other embodiments, such as Figure 5 As shown, the winding core 120 can also be aligned along the curve segment S, depending on the intended use of the battery 100. The curve segment S can be an arc segment, a parabola segment, etc., and is not limited here.

[0062] When the core 120 extends along the curved segment S, the first tab 126 and the second tab 127 of the core 120 can be located at one end of the extension direction of the core 120, and the plane containing the curved segment S is perpendicular to the width direction Y of the first electrode 121. When the core 120 is bent to form a curved structure extending along the curved segment S, the bending stress of the first electrode 121, the second electrode 122, and the diaphragm 123 of the core 120 can be reduced, so that the first electrode 121, the second electrode 122, and the diaphragm 123 maintain a smooth structure and are less prone to corner bending, powder shedding, short circuits, etc.

[0063] This application also provides a battery 100, which includes a core 120. The specific structure of the core 120 is as described in the above embodiments. Since the battery 100 adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0064] Among them, such as Figure 5 As shown, the battery 100 may include a housing 110 and a winding core 120. The housing 110 has a mounting cavity 1101, and the winding core 120 is mounted in the mounting cavity 1101 of the housing 110. The structure of the winding core 120 can be referred to in the various embodiments of the winding core 120 above, and will not be described again here.

[0065] The battery 100 provided in this application embodiment, by placing the second winding tail end 1222 of the second electrode 122 of the core 120 inside the first electrode 121 and by including an uncoated section 1214 extending from the first winding tail end 1212 to the first winding head end 1211 on the outer surface 1213 of the first electrode 121, can reduce the thickness of a section of the first electrode 121 near the first winding tail end 1212 without affecting the electrical performance of the core 120, thereby reducing the overall outer diameter of the core 120. While not changing the charge of the core 120, the overall volume of the core 120 is reduced, thereby increasing the energy density of the core 120 and thus increasing the energy density of the battery 100.

[0066] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A core, characterized in that, The core comprises a first pole piece, a second pole piece and a separator which are stacked and wound, the first pole piece and the second pole piece have opposite polarities, and the separator is arranged between the first pole piece and the second pole piece; the first pole piece comprises a first winding head end and a first winding tail end, and the second pole piece comprises a second winding head end and a second winding tail end, and the second winding tail end is located on the inner side of the first pole piece. The first pole piece comprises an outer side surface located on the outer side of the first pole piece, and the outer side surface comprises a non-coating section extending from the first winding tail end to the first winding head end.

2. The core of claim 1 wherein, The length of the non-coating section is less than or equal to the outer circumferential length of the core.

3. The core of claim 1 wherein, The length of the non-coating section is greater than or equal to 10 mm and less than or equal to 300 mm.

4. The core of claim 1 wherein, The first pole piece is a positive pole piece or a negative pole piece.

5. The core according to any one of claims 1 to 4, wherein The outer side surface further comprises a coating section extending from the non-coating section to the first winding head end, and the coating section is coated with an active coating layer. The core further comprises a protective layer covering the junction of the coating section and the non-coating section.

6. The core of any one of claims 1 to 4, wherein Part of the separator covers the non-coating section.

7. The core of any one of claims 1 to 4, wherein The first winding tail end of the first pole piece is welded with a first tab extending along the length direction of the first pole piece, and the second winding tail end of the second pole piece is welded with a second tab extending along the length direction of the second pole piece, and the first tab and the second tab are spaced apart along the width direction of the first pole piece.

8. The core of claim 7 wherein, The first pole piece comprises an inner side surface opposite to the outer side surface, and the inner side surface comprises a welding section extending from the first winding tail end to the first winding head end, the welding section is welded with the first tab, and the length of the welding section is less than the length of the non-coating section.

9. The core of claim 7 wherein, The core extends along a curved section, the first tab and the second tab are located at one end of the extension direction of the core, and the plane where the curved section is located is perpendicular to the width direction of the first pole piece.

10. A battery, characterized by The core comprises: a housing having a mounting cavity; a core as claimed in any one of claims 1 to 9, the core being mounted in the mounting cavity.

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