Cylindrical batteries and battery packs

Abstract

This utility model relates to the technical field of batteries, and provides a cylindrical battery and a battery pack. The cylindrical battery includes: a shell and a core; the core is disposed inside the shell, the core has a winding direction, and the core has a winding strip wound along the winding direction; the winding strip includes a first electrode, a second electrode, and a first separator stacked together; the first separator is located between the first electrode and the second electrode, and the polarities of the first electrode and the second electrode are opposite; the winding strip is wound from the inside to the outside along the winding direction to form a folded edge area and an arc area; the folded edge area has a bent portion, the bent portion including a folded edge segment; the arc area includes an arc segment, the arc segment extending along the winding direction. The battery pack includes the aforementioned cylindrical battery. The folded edge segment, through folding, can have higher resistance to deformation, improve the stiffness of the folded edge area, i.e., the inner ring area, and suppress the occurrence of inner ring collapse.

Description

Technical Field

[0001] This utility model belongs to the technical field of batteries, and more specifically, it relates to a cylindrical battery and battery pack. Background Technology

[0002] Currently, in the core (also known as electrode assembly) of lithium-ion cylindrical batteries, the positive electrode current collector is aluminum foil, and the negative electrode current collector is copper foil. Copper foil and aluminum foil have excellent conductivity. However, due to the weak rigidity of the positive electrode sheet and separator, as well as the constraint of the inner ring on the inner ring of the core during the cycle of the cylindrical battery, the electrode sheet is prone to excessive strain, resulting in the collapse of the inner ring, which seriously shortens the cycle life of lithium-ion cylindrical batteries.

[0003] When the inner ring of a cylindrical battery collapses, the inner ring electrode contracts and expands inward or outward. To improve the inner ring collapse of cylindrical cells, the industry has adopted methods such as inserting a center tube and hot-drilling holes. However, these methods are currently difficult to implement and do not significantly improve the cycle life of lithium-ion cylindrical cells. Utility Model Content

[0004] The purpose of this invention is to provide a cylindrical battery and battery pack to solve the technical problem that the inner ring is prone to collapse in the prior art.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is: to provide a cylindrical battery, comprising:

[0006] case;

[0007] A core is disposed within the housing and has a winding direction. The core has a winding strip wound along the winding direction. The winding strip includes a first electrode, a second electrode, and a first diaphragm stacked together. The first diaphragm is located between the first electrode and the second electrode, and the polarities of the first electrode and the second electrode are opposite.

[0008] The winding strip is wound from the inside to the outside along the winding direction to form a folded edge area and an arc area; the folded edge area has a bent portion, the bent portion including a folded edge segment; the arc area includes an arc segment, the arc segment extending along the winding direction.

[0009] Furthermore, the bending portion also includes a connecting segment; there are multiple folded edges, and a connecting segment connects any two adjacent folded edges.

[0010] Furthermore, the folded edge area has a plurality of first concentric rings, and each of the first concentric rings of the folded edge area has at least one of the bending portions.

[0011] Furthermore, the cylindrical battery also includes a first tab and a second tab; the first tab is disposed on the first electrode plate on the arc segment; and the second tab is disposed on the second electrode plate on the arc segment.

[0012] Furthermore, the core also has a first direction, the first electrode on the arc segment has multiple second layers, the second electrode on the arc segment has multiple third layers, and the first electrode tab and the second electrode tab are respectively disposed on opposite sides of the core in the first direction;

[0013] The number of first electrodes is multiple and they are spaced apart along the winding direction. Each second layer is provided with multiple first electrodes, and at least two first electrodes of two adjacent second layers are stacked and electrically connected.

[0014] The number of second electrodes is multiple and they are spaced apart along the winding direction. Each third layer is provided with multiple second electrodes, and at least two second electrodes of two adjacent third layers are stacked and electrically connected.

[0015] Furthermore, the core also has a first direction, the first electrode on the arc segment has multiple second layers, the second electrode on the arc segment has multiple third layers, and the first electrode tab and the second electrode tab are both located on the same side of the core in the first direction;

[0016] Each second layer is provided with a first electrode tab, each third layer is provided with a second electrode tab, and the second electrode tabs and the first electrode tabs are spaced apart in the winding direction. All the first electrode tabs are stacked and electrically connected, and all the second electrode tabs are stacked and electrically connected.

[0017] Furthermore, it also includes: a second diaphragm; the first electrode or the second electrode is located between the first diaphragm and the second diaphragm;

[0018] The winding strip also has a starting area, and when the winding strip is in the unfolded state, the folded edge area is located between the starting area and the arc area;

[0019] The first electrode has a first starting end in the winding direction, the second electrode has a second starting end in the winding direction, the first diaphragm has a third starting end in the winding direction, the second diaphragm has a fourth starting end in the winding direction, the first starting end and the second starting end are located in the folded edge area, and the third starting end and the fourth starting end are located in the starting area.

[0020] Furthermore, the core also has a center hole; the third starting end and the fourth starting end are located within the center hole.

[0021] Furthermore, the housing includes a housing body and a top cover, the core is disposed within the housing body, and the top cover is connected to the housing body;

[0022] The cylindrical battery further includes: a terminal post, a first current collector and a second current collector, the terminal post passing through the top cover, the first current collector electrically connecting the first tab and the terminal post, and the second current collector electrically connecting the second tab and the casing body;

[0023] The folded edge area has multiple first concentric rings, and each first concentric ring has the same number of folded edge segments.

[0024] This utility model also provides a battery pack, including the aforementioned cylindrical battery.

[0025] The beneficial effects of the cylindrical battery provided by this utility model are as follows: Compared with the prior art, the cylindrical battery provided by this utility model has a wound core with a wound strip inside the casing. The first separator is located between the first electrode and the second electrode, thereby insulating the first electrode and the second electrode with opposite polarities. The wound strip is wound from the inside to the outside to form a folded edge area and an arc area, that is, the folded edge area is located on the inner side of the core. A bending part is provided in the folded edge area, and the bending part includes a folded edge segment. The folded edge segment can have higher resistance to deformation through folding, improve the rigidity of the folded edge area, that is, the inner area, suppress the occurrence of inner ring collapse, and extend the service life of the cylindrical battery. The arc area has an arc segment, which wraps around the outer side of the folded edge area, that is, the outer ring. The wound strip of the outer ring is wound in a circle, which extends the arc segment. Attached Figure Description

[0026] Figure 1 A schematic diagram of the core in a cylindrical battery provided in an embodiment of this application;

[0027] Figure 2 for Figure 1 An enlarged schematic diagram of region A in the embodiment;

[0028] Figure 3 This is a schematic diagram showing the unwound tape provided in an embodiment of this application;

[0029] Figure 4 This is a schematic diagram of the overall structure of the cylindrical battery provided in an embodiment of this application.

[0030] The following are the labeling elements in the figure:

[0031] 10-Core; 11-First electrode; 12-Second electrode; 21-First diaphragm; 22-Second diaphragm; 31-Center hole; 51-Shell; 511-Shell body; 512-Top cover; 52-Electrode post; N-Inner end; W-Outer end; C-Folded edge area; C1-Bending part; C11-Folded edge section; C12-Connecting section; R-Winding direction; Y-Arc area; Y1-Arc section; J-Winding strip; J1-Starting area; X-First direction. Detailed Implementation

[0032] It should be noted that the specific embodiments are only used to explain the present invention and are not intended to limit the present invention.

[0033] It should be noted that, in the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Here, A and B can be singular or plural, respectively.

[0034] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as "connected to" or "attached to" another component, it can be directly connected to or indirectly connected to that other component. When a component is referred to as "fixed to" or "set on" another component, it can be directly on or indirectly on that other component.

[0035] It should be noted that the terms "length", "width", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" 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 this utility model 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 this utility model.

[0036] It should be noted that 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 with "first" or "second" may explicitly or implicitly include one or more of that feature.

[0037] It should be noted that the term "multiple" means two or more, unless otherwise explicitly specified.

[0038] Please refer to the following: Figures 1 to 4 The cylindrical battery provided by this utility model will now be described. The cylindrical battery includes: a housing 51 and a core 10; the core 10 is disposed inside the housing 51, the core 10 has a winding direction R, and the core 10 has a winding strip J wound along the winding direction R; the winding strip J includes a first electrode 11, a second electrode 12 and a first separator 21 stacked together; the first separator 21 is located between the first electrode 11 and the second electrode 12, and the polarities of the first electrode 11 and the second electrode 12 are opposite; the winding strip J is wound from the inside to the outside along the winding direction R to form a folded edge region C and an arc region Y; the folded edge region C has a bent portion C1, the bent portion C1 includes a folded edge segment C11; the arc region Y includes an arc segment Y1, the arc segment Y1 extends along the winding direction R.

[0039] Thus, the core 10 inside the casing 51 has a wound strip J, and the first diaphragm 21 is located between the first electrode 11 and the second electrode 12, thereby insulating the first electrode 11 and the second electrode 12 with opposite polarities. The wound strip J is wound from the inside to the outside to form a folded edge area C and an arc area Y. That is, the folded edge area C is located in the inner circle of the core 10. A bending part C1 is provided in the folded edge area C. The bending part C1 includes a folded edge segment C11. The folded edge segment C11 can have higher resistance to deformation through folding, improve the stiffness of the folded edge area C, i.e., the inner circle area, suppress the occurrence of inner circle collapse, and extend the service life of the cylindrical battery. The arc area Y has an arc segment, which wraps around the outside of the folded edge area C, i.e., the outer circle. The wound strip J of the outer circle is wound in a circle and extends.

[0040] It should be noted that:

[0041] The winding tape J is wound from the inside out. Here, winding from the inside out means that when winding, one end of the winding tape is fixed to the winding needle, and then the winding tape J starts to wind along the winding direction R. The first few turns are closest to the winding needle and belong to the inner circle or inner side. As the winding continues, the turns are further and further away from the winding needle, and these turns belong to the outer circle relative to the inner circle.

[0042] The folded edge area C refers to a region containing a bend C1, which includes a folded edge segment C11. The area containing the folded edge segment C11 roughly corresponds to the folded edge area C. The arc area, on the other hand, refers to a region where, due to the presence of the folded edge area C, each turn of the winding tape J is not circular. As winding progresses, the diameter increases, and the non-circular contour caused by the bend C1 gradually transforms into a circular contour. This part of the winding tape J essentially extends in an arc along the winding direction R to form a circular contour; this part is called the arc area. In one embodiment, the winding direction R is a helical direction. In another embodiment, the helix winds counterclockwise or clockwise.

[0043] In one embodiment, combined Figure 1 and Figure 2 As shown, the core 10 is wound from the inside out, with the folded edge area C located on the inner ring / inner end N and the arc area Y located on the outer ring / outer end W.

[0044] In one embodiment, the first diaphragm 21 can separate the first electrode 11 and the second electrode 12.

[0045] In one embodiment, the housing 51 has a receiving cavity in which the core 10 can be housed.

[0046] In one embodiment, the folded edge segment C11 can be a non-circular extension structure extending in a straight line. In another embodiment, the folded edge segment C11 can also be a wavy extension.

[0047] Further, please refer to Figures 1 to 4 As a specific embodiment of the cylindrical battery provided by this utility model, the bending portion C1 further includes a connecting segment C12; multiple folded edge segments C11 are provided, and a connecting segment C12 connects any two adjacent folded edge segments C11. In this way, folded edge segments C11 with different values ​​along the winding direction R can improve the bending resistance of the core 10 at different positions.

[0048] Furthermore, the multiple bends C1 are distributed along the winding direction R, so that when the core 10 is subjected to external bending force, the deformation is no longer solely borne by a single bend C1, but rather each bend C1 shares the stress at different locations. This results in a uniform stress distribution across the core 10 as a whole, effectively reducing the risk of cracks or collapse caused by localized stress concentration.

[0049] The folded edge segment C11 can be formed by winding a polygonal needle, with the sides of the polygon causing the winding portion of the corresponding winding tape J to form the folded edge segment C11.

[0050] Further, please refer to Figures 1 to 4 In one specific embodiment of the cylindrical battery provided by this utility model, the folded edge region C has multiple first rings, and each first ring of the folded edge region C has at least one bending portion C1. Thus, each ring of the folded edge region C has a bending portion C1 capable of resisting bending of the core 10.

[0051] It should be noted that: the first layer refers to the winding strip that forms a circle around the outer periphery of the core. Since there are multiple circles after winding, and adjacent circles are stacked together, each circle is called a layer. In this embodiment, only one circle can be wound to form the folded edge area C, in which case the folded edge area C has only one first layer; of course, multiple circles can also be wound to form the folded edge area C, in which case the folded edge area C includes not just one first layer, but multiple first layers, such as 5 circles or 8 circles, thus forming a folded edge area C with 5 first layers or 8 first layers. In addition, the meaning of the second and third layers mentioned later is the same as that of the first layer, and will not be repeated.

[0052] In addition, since each turn contains at least one bend C1, no matter where the core 10 bends, there is a corresponding folded edge area C—the bend C1—to bear and alleviate the bending. Stress will not be concentrated and accumulated in a single folded edge area C, thereby significantly improving the overall durability of the core 10 in multiple bending cycles.

[0053] In addition, the multi-loop structure of the folded edge area C can absorb and buffer dimensional changes.

[0054] Further, please refer to Figures 1 to 4 As a specific embodiment of the cylindrical battery provided by this utility model, the cylindrical battery further includes a first tab and a second tab; the first tab is provided on the first electrode plate 11 on the arc segment Y1; and the second tab is provided on the second electrode plate 12 on the arc segment Y1. Thus, the first tab and the second tab allow connection to external positive and negative electrodes.

[0055] Furthermore, the first and second tabs are respectively disposed on the arc segment Y1 of the winding core 10, allowing the first tab to be directly connected to an external electrode, such as a positive electrode, and the second tab to be directly connected to an external electrode, such as a negative electrode, thereby enabling charging and discharging. Additionally, placing the tabs in the arc segment Y avoids affecting the anti-inner-ring collapse function of the folded edge area C.

[0056] In addition, by arranging the first and second electrodes on the arc segment Y1, which matches the geometry of the core 10, the electrodes can be tightly fitted with external positive and negative electrodes such as pole posts 52 and current collectors.

[0057] In one embodiment, the first tab can be connected to the section of the first electrode 11 located in the middle of the arc region Y; the second tab can be connected to the section of the second electrode 12 located in the middle of the arc region Y. In this way, the stress on the first tab can be transmitted from the middle section of the first electrode 11 to both ends of the first electrode 11, and the stress on the first tab can be dispersed along the first electrode 11 as quickly as possible, and the same applies to the second tab.

[0058] Further, please refer to Figures 1 to 4As a specific embodiment of the cylindrical battery provided by this utility model, the core 10 also has a first direction X, the first electrode 11 on the arc segment Y1 has multiple second layers, the second electrode 12 has multiple third layers, the first electrode tab and the second electrode tab are respectively disposed on opposite sides of the core 10 in the first direction X; the number of first electrode tabs is multiple and they are spaced apart along the winding direction R, each second layer is provided with multiple first electrode tabs, and at least two first electrode tabs of two adjacent second layers are stacked and electrically connected; the number of second electrode tabs is multiple and they are spaced apart along the winding direction R, each third layer is provided with multiple second electrode tabs, and at least two second electrode tabs of two adjacent third layers are stacked and electrically connected.

[0059] In this way, multiple first tabs are stacked together and welded; multiple second tabs are stacked together and welded, which not only reduces the space occupied, but also reduces the internal resistance of the battery. Since the first tabs and second tabs are respectively located on opposite sides of the core 10, with tabs extending from both sides, a full tab structure can be formed through a flattening process or a cutting and flattening process, which greatly reduces the internal resistance of the battery.

[0060] Further, please refer to Figures 1 to 4 As a specific embodiment of the cylindrical battery provided by this utility model, the core 10 also has a first direction X, a first electrode 11 on the arc segment Y1 having multiple second layers, a second electrode 12 having multiple third layers, and a first tab and a second tab both located on the same side of the core 10 in the first direction X; each second layer has a first tab, each third layer has a second tab, and the second tabs and the first tabs are spaced apart in the winding direction R. All the first tabs are stacked and electrically connected, and all the second tabs are stacked and electrically connected. In this scheme, the first tabs and the second tabs both emerge from the same side. Compared with the structure where the tabs emerge from both sides separately, the overall height of the battery can be effectively reduced, thereby increasing the energy density of the battery.

[0061] Further, please refer to Figures 1 to 4As a specific embodiment of the cylindrical battery provided by this utility model, it further includes: a second separator 22; a first electrode 11 or a second electrode 12 located between the first separator 21 and the second separator 22; the winding tape J also has a starting region J1, and when the winding tape J is in the unfolded state along the winding direction R, the folded edge region C is located between the starting region J1 and the arc region Y; the first electrode 11 has a first starting end in the winding direction R, the second electrode 12 has a second starting end in the winding direction R, the first separator 21 has a third starting end in the winding direction R, the second separator 22 has a fourth starting end in the winding direction R, the first starting end and the second starting end are located in the folded edge region C, and the third starting end and the fourth starting end are located in the starting region J1. Thus, the first diaphragm 21 and the second diaphragm 22 start from the starting region J1, and the first electrode 11 and the second electrode 12 start from the folded edge region C; that is, the first diaphragm 21 and the second diaphragm 22 start to be rolled up first, and then the first electrode 11 and the second electrode 12 are arranged, which avoids leakage of the first electrode 11 and the second electrode 12 at the starting position.

[0062] Further, please refer to Figures 1 to 4 As a specific embodiment of the cylindrical battery provided by this utility model, the core 10 also has a central hole 31; the third starting end and the fourth starting end are located inside the central hole 31. In this way, the third starting end and the fourth starting end can be housed inside the central hole 31.

[0063] Further, please refer to Figures 1 to 4 As a specific embodiment of the cylindrical battery provided by this utility model, the casing 51 includes a casing body 511 and a top cover 512. The core 10 is disposed inside the casing body 511, and the top cover 512 is connected to the casing body 511. The cylindrical battery also includes: a terminal post 52, a first current collector and a second current collector. The terminal post 52 passes through the top cover 512. The first current collector is electrically connected to the first tab and the terminal post 52. The second current collector is electrically connected to the second tab and the casing body 511. The folded edge area C has multiple first rings, and each first ring has the same number of folded edge segments C11.

[0064] Thus, the first tab can transmit current to the pole post 52 through the first current collector, and the second tab can transmit current to the shell body 511 through the second current collector; each first ring has the same number of folded edge segments C11, making the bending resistance of different first rings more balanced.

[0065] Please see Figures 1 to 4 The present invention also provides a battery pack, including the cylindrical battery described in any of the above embodiments.

[0066] Thus, due to the adoption of the above-mentioned cylindrical battery, the core 10 inside the casing 51 has a wound strip J, and the first separator 21 is located between the first electrode 11 and the second electrode 12, thereby insulating the first electrode 11 and the second electrode 12 with opposite polarities. The wound strip J is wound from the inside to the outside to form a folded edge area C and an arc area Y, that is, the folded edge area C is located in the inner circle of the core 10; a bending part C1 is provided in the folded edge area C, the bending part C1 includes a folded edge segment C11, the folded edge segment C11 can have higher resistance to deformation through folding, improve the stiffness of the folded edge area C, that is, the inner circle area, suppress the occurrence of inner circle collapse, and extend the service life of the cylindrical battery; while the arc area Y has an arc segment, the arc segment wraps around the outside of the folded edge area C, that is, the outer circle, and the wound strip J of the outer circle is wound in a circle and extends.

[0067] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present utility model, and these improvements and substitutions should also be considered within the protection scope of the present utility model.

Claims

1. A cylindrical battery, characterized in that, include: Shell (51); A core (10) is disposed within the housing (51). The core (10) has a winding direction (R) and a winding strip (J) wound along the winding direction (R). The winding strip (J) includes a first electrode (11), a second electrode (12), and a first diaphragm (21) stacked together. The first diaphragm (21) is located between the first electrode (11) and the second electrode (12), and the polarities of the first electrode (11) and the second electrode (12) are opposite. The winding strip (J) is wound from the inside to the outside along the winding direction (R) to form a folded edge area (C) and an arc area (Y); the folded edge area (C) has a bent portion (C1), the bent portion (C1) including a folded edge segment (C11); the arc area (Y) includes an arc segment (Y1), the arc segment (Y1) extending along the winding direction (R).

2. The cylindrical battery as described in claim 1, characterized in that, The bending portion (C1) further includes a connecting segment (C12); there are multiple folded edges (C11), and any two adjacent folded edges (C11) are connected by a connecting segment (C12).

3. The cylindrical battery as described in claim 2, characterized in that, The folded edge area (C) has a plurality of first concentric rings, and each of the first concentric rings of the folded edge area (C) has at least one of the bent portions (C1).

4. The cylindrical battery as described in claim 2, characterized in that, The cylindrical battery also includes a first tab and a second tab; the first tab is provided on the first electrode (11) on the arc segment (Y1); the second tab is provided on the second electrode (12) on the arc segment (Y1).

5. The cylindrical battery as described in claim 4, characterized in that, The core (10) also has a first direction (X), the first pole piece (11) on the arc segment (Y1) has a plurality of second rings, the second pole piece (12) on the arc segment (Y1) has a plurality of third rings, and the first pole piece and the second pole piece are respectively disposed on opposite sides of the core (10) in the first direction (X); The number of first electrodes is multiple and they are spaced apart along the winding direction (R). Each second layer is provided with multiple first electrodes, and at least two first electrodes of two adjacent second layers are stacked and electrically connected. The number of second electrodes is multiple and they are spaced apart along the winding direction (R). Each third layer is provided with multiple second electrodes, and at least two second electrodes of two adjacent third layers are stacked and electrically connected.

6. The cylindrical battery as described in claim 4, characterized in that, The core (10) also has a first direction (X), the first pole piece (11) on the arc segment (Y1) has a plurality of second rings, the second pole piece (12) on the arc segment (Y1) has a plurality of third rings, and the first pole piece and the second pole piece are both located on the same side of the core (10) in the first direction (X); Each second layer is provided with a first electrode tab, each third layer is provided with a second electrode tab, and the second electrode tabs and the first electrode tabs are spaced apart in the winding direction (R). All the first electrode tabs are stacked and electrically connected, and all the second electrode tabs are stacked and electrically connected.

7. The cylindrical battery as described in claim 1, characterized in that, Also includes: The second diaphragm (22); the first electrode (11) or the second electrode (12) is located between the first diaphragm (21) and the second diaphragm (22); The winding strip (J) also has a starting area (J1), and when the winding strip (J) is in the unfolded state, the folded edge area (C) is located between the starting area (J1) and the arc area (Y); The first electrode (11) has a first starting end in the winding direction (R), the second electrode (12) has a second starting end in the winding direction (R), the first diaphragm (21) has a third starting end in the winding direction (R), the second diaphragm (22) has a fourth starting end in the winding direction (R), the first starting end and the second starting end are located in the folded edge area (C), and the third starting end and the fourth starting end are located in the starting area (J1).

8. The cylindrical battery as described in claim 7, characterized in that, The core (10) also has a center hole (31); the third starting end and the fourth starting end are located within the center hole (31).

9. The cylindrical battery as described in claim 4, characterized in that, The housing (51) includes a housing body (511) and a top cover (512), the core (10) is disposed inside the housing body (511), and the top cover (512) is connected to the housing body (511). The cylindrical battery further includes: a terminal post (52), a first current collector and a second current collector. The terminal post (52) passes through the top cover (512). The first current collector is electrically connected to the first tab and the terminal post (52). The second current collector is electrically connected to the second tab and the shell body (511). The folded edge area (C) has multiple first concentric rings, each of which has the same number of folded edge segments (C11).

10. A battery pack, characterized in that, Including the cylindrical battery as described in any one of claims 1-9.

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