A type of wound core and cylindrical battery

Abstract

This utility model discloses a wound core and a cylindrical battery. The wound core includes a positive electrode sheet, a separator, and a negative electrode sheet, with the separator disposed between the positive and negative electrode sheets. A negative electrode tab is provided on one side of the negative electrode sheet, located at the Kth turn of the negative electrode sheet. A first notch is provided on the (K+1)th or (K-1)th turn of the positive electrode sheet, directly opposite the negative electrode tab, and the negative electrode tab is inserted into the first notch. A positive electrode tab is provided on one side of the positive electrode sheet, located at the Nth turn of the positive electrode sheet. A second notch is provided on the (N+1)th or (N-1)th turn of the negative electrode sheet, directly opposite the positive electrode tab, and the positive electrode tab is inserted into the second notch. In this design, the positive and negative electrode tabs do not protrude outwards, allowing for a greater number of turns of the wound core with a fixed diameter, resulting in more active material inside the wound core and thus improving the battery's energy density.

Description

Technical Field

[0001] This utility model relates to the technical field of batteries, and in particular to a wound core and cylindrical battery. Background Technology

[0002] Please see Figure 1 In cylindrical batteries, cells are typically formed by winding a positive electrode, a separator, and a negative electrode. After the winding is completed, the positive tab 3 (connected to the positive electrode) and the negative tab 4 (connected to the negative electrode) are quite thick, occupying a significant amount of thickness space, typically 0.05-0.1 mm. Therefore, when designing the core diameter, the diameter A of the tab position must be used as the core diameter, resulting in a shorter usable electrode length. In fact, in existing structures, a large gap remains between the core and the inner wall of the casing after insertion. This gap cannot be utilized by the electrodes, leading to a lower energy density and consequently a shorter battery life for cylindrical batteries. Therefore, improvements to the existing core design are necessary. Utility Model Content

[0003] This utility model provides a wound core and a cylindrical battery, which mainly solves the technical problem of low battery energy density caused by excessively thick and protruding tabs in existing wound cores.

[0004] To achieve the above objectives, this utility model provides the following technical solution:

[0005] A winding core includes a positive electrode sheet, a separator, and a negative electrode sheet, wherein the separator is disposed between the positive electrode sheet and the negative electrode sheet;

[0006] A negative electrode tab is provided on one side of the negative electrode sheet. The negative electrode tab is located in the Kth turn of the negative electrode sheet. A first notch is provided on the (K+1)th turn or the (K-1)th turn, and at the position directly opposite the negative electrode tab. The negative electrode tab is inserted into the first notch.

[0007] A positive electrode tab is provided on one side of the positive electrode plate. The positive electrode tab is located in the Nth turn of the positive electrode plate. A second notch is provided on the (N+1)th or (N-1)th turn of the negative electrode plate, which is directly opposite the positive electrode tab. The positive electrode tab is inserted into the second notch.

[0008] In one technical solution, a third notch is provided on the part of the positive electrode plate facing the second notch, and the positive electrode tab is received in the second notch and the third notch;

[0009] The negative electrode sheet has a fourth notch at the position opposite to the first notch, and the negative electrode tab is accommodated in the first notch and the fourth notch.

[0010] In one of the technical solutions, the positive electrode tab and the negative electrode tab are located at the same end of the winding core or at different ends of the winding core.

[0011] In one of the technical solutions, when the positive electrode and the negative electrode are in the unfolded state, the ends along the length direction X are respectively the first end and the second end, the first end is used to be wound in the innermost part, and the second end is used to be wound in the outermost part;

[0012] The first notch and the third notch are both arranged on one side of the positive electrode tab along the length direction X, and the second notch and the fourth notch are both arranged on one side of the negative electrode tab along the length direction X, or;

[0013] The first notch and the third notch are both arranged on the side opposite to the length direction X of the positive electrode tab, and the second notch and the fourth notch are both arranged on the side opposite to the length direction X of the negative electrode tab, or;

[0014] One of the first notch and the third notch is arranged on one side of the positive electrode tab along the length direction X, and the other is arranged on the side of the positive electrode tab in the opposite direction of the length direction X; one of the second notch and the fourth notch is arranged on one side of the negative electrode tab along the length direction X, and the other is arranged on the side of the negative electrode tab in the opposite direction of the length direction X.

[0015] In one technical solution, the width direction of the positive electrode and the negative electrode when they are in the unfolded state is the Y direction. The positive electrode tab extends in the Y direction, and the negative electrode tab extends in the opposite direction of the Y direction. The openings of the first notch and the fourth notch are both facing the opposite direction of the Y direction, and the openings of the second notch and the third notch are both facing the Y direction.

[0016] In one technical solution, the width of the overlap between the positive electrode tab and the positive electrode sheet does not exceed half the width of the positive electrode sheet, and the width of the overlap between the negative electrode tab and the negative electrode sheet does not exceed half the width of the negative electrode sheet.

[0017] In one of the technical solutions, the width of the positive electrode tab is denoted as a, the width of the second notch is denoted as a1, and the width of the third notch is denoted as a2, wherein a ≤ a1 ≤ a2.

[0018] In one of the technical solutions, a2 is 0.5mm-1mm larger than a.

[0019] In one of the technical solutions, the width of the negative electrode tab is b, the width of the fourth notch is b1, and the width of the first notch is b2, wherein b ≤ b1 ≤ b2.

[0020] In one of the technical solutions, b2 is 0.5mm-1mm larger than b.

[0021] In one of the technical solutions, the core is wound into a roughly circular shape, and the central angles of the positive electrode tab and the negative electrode tab are both between 70° and 110°.

[0022] This application also provides a cylindrical battery, including a casing and the aforementioned winding core, the winding core being housed within the casing, the casing including an insulated and sealed positive electrode housing and a negative electrode housing, the positive electrode tab being connected to the positive electrode housing, and the negative electrode tab being connected to the negative electrode housing.

[0023] Compared with the prior art, the winding core provided by this utility model has at least the following beneficial effects:

[0024] This design incorporates a first notch on the positive electrode and a second notch on the negative electrode. This allows the negative electrode tab to be embedded in the first notch and the positive electrode tab in the second notch during the winding process of the positive electrode, separator, and negative electrode. This prevents the positive and negative electrode tabs from protruding outwards. Consequently, with a fixed core diameter, the core can utilize longer positive and negative electrode sheets, which increases the number of winding turns and allows for more active material inside the core, thereby improving the battery's energy density. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 A structural schematic diagram of a winding core provided for the prior art;

[0027] Figure 2 A first design method for the positive and negative electrode sheets within a winding core, as provided in the embodiments of this application;

[0028] Figure 3 A schematic diagram of the structure of a winding core provided in this application embodiment;

[0029] Figure 4This application provides a second design for the positive and negative electrode sheets within a winding core.

[0030] Figure 5 This application provides a third design method for the positive and negative electrode sheets within a winding core;

[0031] Figure 6 This is a schematic diagram of the structure of the core at the positive electrode tab in an embodiment of this application;

[0032] Figure 7 This is a schematic diagram of the structure of the core at the negative electrode tab in an embodiment of this application.

[0033] Figure label:

[0034] 1. Positive electrode plate; 11. First notch; 12. Third notch; 2. Negative electrode plate; 21. Second notch; 22. Fourth notch; 3. Positive tab; 4. Negative tab; 10. First end; 20. Second end. Detailed Implementation

[0035] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0036] It should be noted that when a component is referred to as being "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 being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0037] It should be understood that the terms "upper", "lower", "top", "bottom", "inner", "outer", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0038] Furthermore, 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. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0039] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments.

[0040] Please refer to the following: Figure 2 , Figure 3 , Figure 6 and Figure 7 This utility model embodiment provides a winding core, which includes a positive electrode 1, a separator (not shown in the figure), and a negative electrode 2. The separator is disposed between the positive electrode 1 and the negative electrode 2 to insulate and separate the positive electrode 1 and the negative electrode 2, preventing the positive electrode 1 and the negative electrode 2 from contacting and causing a short circuit. A positive electrode tab 3 is connected to the positive electrode 1, and a negative electrode tab 4 is connected to the negative electrode 2. Please refer to [reference needed]. Figure 7 Assume the negative electrode tab 4 is located in the Kth turn of the negative electrode plate, and the positive electrode plate 1 has a first notch 11 in the (K+1)th or (K-1)th turn, directly opposite the negative electrode tab 4, and the negative electrode tab 4 is embedded in the first notch 11; please refer to Figure 6 Let the positive electrode tab 3 be located on the Nth turn of the positive electrode sheet 1, and the negative electrode sheet 2 have a second notch 21 on the (N+1)th or (N-1)th turn, directly opposite the positive electrode tab 3. The positive electrode tab 3 is embedded in the second notch 21. By setting the first notch 11 and the second notch 21, when the diameter of the core is constant, the core can use a longer positive electrode sheet 1 and a longer negative electrode sheet 2. That is, it is beneficial to increase the number of turns of the core winding, so that the core can have more active material, thereby improving the energy density of the battery. Here, N and K are both positive integers, and K and N can be equal or unequal.

[0041] Please refer to them again. Figure 2 , Figure 3 , Figure 6 and Figure 7 The positive electrode 1 has a third notch 12 on the part facing the second notch 21, and the aforementioned positive electrode tab 3 is simultaneously housed within both the second notch 21 and the third notch 12. The negative electrode 2 has a fourth notch 22 on the part facing the first notch 11, and the negative electrode tab 4 is simultaneously housed within both the first notch 11 and the fourth notch 22. By further providing the third notch 12 and the fourth notch 22, even when the positive electrode tab 3 and the negative electrode tab 4 are relatively thick, they can still be accommodated, thereby further reducing the outer diameter of the core. In other words, when the outer diameter of the core is fixed, the core can be wound more times, which is beneficial to further improving the energy density of the battery.

[0042] Please refer to it again. Figure 2Let the positive electrode 1 and the negative electrode 2 be in the unfolded state, with the ends along the length direction X being the first end 10 and the second end 20, respectively. The first end 10 is used to be wound in the innermost position, and the second end 20 is used to be wound in the outermost position. The specific positions of the first notch 11, the third notch 12, the second notch 21, and the fourth notch 22 can be arranged according to the following three design methods:

[0043] The first design approach: (e.g.) Figure 2 As shown, the first notch 11 and the third notch 12 are both arranged on one side of the positive electrode tab 3 along the length direction X, and correspondingly, the second notch 21 and the fourth notch 22 are both arranged on one side of the negative electrode tab 4 along the length direction X. In this design, the first notch 11 can preferably be designed to be closer to the second end 20 than the third notch 12, and the fourth notch 22 can preferably be designed to be closer to the second end 20 than the third notch 12.

[0044] The second design approach: such as Figure 4 As shown, the first notch 11 and the third notch 12 are both arranged on the side opposite to the length direction X of the positive electrode tab 3, and correspondingly, the second notch 21 and the fourth notch 22 are both arranged on the side opposite to the length direction X of the negative electrode tab 4.

[0045] The third design approach: such as Figure 5 As shown, one of the first notch 11 and the third notch 12 is arranged on one side of the positive electrode 3 along the length direction X, and the other is arranged on the opposite side of the positive electrode 3 along the length direction X. Correspondingly, one of the second notch 21 and the fourth notch 22 is arranged on one side of the negative electrode 4 along the length direction X, and the other is arranged on the opposite side of the negative electrode 4 along the length direction X.

[0046] All three design methods described above can achieve the purpose of housing the positive electrode tab 3 and the negative electrode tab 4. This embodiment preferably adopts the method described above. Figure 2 The first design shown not only accommodates the positive electrode tab 3 and the negative electrode tab 4, but also effectively restricts their positions. This reduces the risk of the positive electrode tab 3 and the negative electrode tab 4 detaching from their corresponding notches, thus helping the core to maintain its position. Figure 2 The diameter A shown is used for insertion into the shell.

[0047] In one of the technical solutions, the diaphragm can be provided with a fifth notch at the position corresponding to the first notch 11, and the diaphragm can also be provided with a sixth notch at the position corresponding to the third notch 12. At this time, the negative electrode tab 4 is equivalent to being housed in the fifth notch, and the positive electrode tab 3 is equivalent to being housed in the sixth notch.

[0048] In another technical solution, the diaphragm may not have the aforementioned fifth and sixth notches. In this case, part of the diaphragm is squeezed by the positive electrode tab 3 and is contained together with the positive electrode tab 3 into the second notch 21 and the third notch 12. At the same time, another part of the diaphragm is squeezed by the negative electrode tab 4 and is contained together with the negative electrode tab 4 into the first notch 11 and the fourth notch 22.

[0049] Please see Figure 2 , Figure 4 or Figure 5 Let the width direction of the positive electrode 1 and the negative electrode 2 in their unfolded state be the Y direction. In this embodiment, the positive electrode tab 3 is preferably designed to extend along the Y direction, and the negative electrode tab 4 is designed to extend in the opposite direction of the Y direction. This design facilitates the arrangement of the positive and negative electrodes of the battery in a relatively opposite manner. Based on this, the openings of the first notch 11 and the fourth notch 22 need to face in the opposite direction of the Y direction, and the openings of the second notch 21 and the third notch 12 need to face in the Y direction. In other embodiments, the positive electrode tab 3 and the negative electrode tab 4 can also be located at the same end of the winding core.

[0050] Please see Figure 2 The overlap width B between the positive electrode tab 3 and the positive electrode sheet 1 does not exceed half the width C of the positive electrode sheet 1, and the overlap width D between the negative electrode tab 4 and the negative electrode sheet 2 does not exceed half the width E of the negative electrode sheet 2. This design ensures that after the positive electrode sheet 1 and the negative electrode sheet 2 are wound, the positive electrode tab 3 will not overlap with the negative electrode tab 4, preventing the positive electrode tab 3 and the negative electrode tab 4 from stacking and causing the outer diameter of the core to increase. This ensures that the core can have a larger number of winding turns with a fixed outer diameter, thereby improving the energy density of the core.

[0051] Please see Figure 3 In this embodiment, the core is roughly circular after winding. The central angle corresponding to the positive electrode tab 3 is between 70° and 110°. Similarly, the central angle corresponding to the negative electrode tab 4 is also between 70° and 110°. This design can also prevent the positive electrode tab 3 and the negative electrode tab 4 from overlapping each other, which would cause the outer diameter of the core to increase. This further ensures that the core can have a large number of winding turns when the outer diameter is constant, which is beneficial to improving the energy density of the core.

[0052] Please see Figure 2The width E of the negative electrode 2 is greater than the width C of the positive electrode 1, and the length of the negative electrode 2 is greater than the length of the positive electrode 1. This ensures that the negative electrode 2 can completely cover the positive electrode 1, preventing lithium ions deposited on the positive electrode 1 from flowing to the negative electrode 2. More specifically, let the width of the positive electrode tab 3 be a, the width of the second notch 21 be a1, and the width of the third notch 12 be a2, where a1 and a2 are both greater than a, so that the positive electrode tab 3 can be accommodated in the second notch 21 and the third notch 12 respectively. Preferably, a2 is 0.5mm-1mm larger than a. Furthermore, a1 is less than a2, which ensures that the negative electrode 2 can completely cover the positive electrode 1, thereby preventing lithium ions deposited on the positive electrode 1 from flowing to the negative electrode 2. In summary, a ≤ a1 ≤ a2. Similarly, let the width of the negative electrode tab 4 be b, the width of the fourth notch 22 be b1, and the width of the first notch 11 be b2, where b1 and b2 are both greater than b, so that the negative electrode tab 4 can be accommodated in the first notch 11 and the fourth notch 22 respectively. Preferably, b2 is 0.5mm-1mm larger than b. In addition, b1 is less than b2, which also ensures that the negative electrode 2 can completely cover the positive electrode 1, thereby preventing lithium ions deposited from the positive electrode 1 from flowing to the negative electrode 2. In summary, b ≤ b1 ≤ b2.

[0053] This embodiment also provides a cylindrical battery, which can be understood as a button cell, AAA battery, AA battery, D battery, I battery, etc. The cylindrical battery includes a casing and the aforementioned winding core, which is housed within the casing. In fact, the casing comprises two shells: one for the positive electrode and the other for the negative electrode. The positive and negative shells are insulated and sealed together. The positive electrode tab 3 of the winding core is actually connected to the positive electrode shell, and the negative electrode tab 4 of the winding core is actually connected to the negative electrode shell. Because this embodiment uses the aforementioned winding core, there is a small gap or even no gap between the winding core and the inner wall of the casing after the winding core is inserted, allowing the cylindrical battery to also have the advantage of high energy density.

[0054] The above are merely preferred embodiments of the present utility model, and only specifically describe the technical principles of the present utility model. These descriptions are only for explaining the principles of the present utility model and should not be construed as limiting the scope of protection of the present utility model in any way. Based on this explanation, any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present utility model, as well as other specific embodiments of the present utility model that can be conceived by those skilled in the art without creative effort, should be included within the scope of protection of the present utility model.

Claims

1. A type of winding core, characterized in that, It includes a positive electrode, a separator, and a negative electrode, wherein the separator is disposed between the positive electrode and the negative electrode; A negative electrode tab is provided on one side of the negative electrode sheet. The negative electrode tab is located in the Kth turn of the negative electrode sheet. A first notch is provided on the (K+1)th turn or the (K-1)th turn, and at the position directly opposite the negative electrode tab. The negative electrode tab is inserted into the first notch. A positive electrode tab is provided on one side of the positive electrode plate. The positive electrode tab is located in the Nth turn of the positive electrode plate. A second notch is provided on the (N+1)th or (N-1)th turn of the negative electrode plate, which is directly opposite the positive electrode tab. The positive electrode tab is inserted into the second notch.

2. The winding core as described in claim 1, characterized in that, The positive electrode plate has a third notch at the position opposite to the second notch, and the positive electrode tab is accommodated in the second notch and the third notch; The negative electrode sheet has a fourth notch at the position opposite to the first notch, and the negative electrode tab is accommodated in the first notch and the fourth notch.

3. The winding core as described in claim 1, characterized in that, The positive electrode tab and the negative electrode tab are located at the same end of the winding core or at different ends of the winding core.

4. The winding core as described in claim 2, characterized in that, a When the positive electrode and the negative electrode are in the unfolded state, their ends along the length direction X are the first end and the second end, respectively. The first end is used to be wound around the innermost part, and the second end is used to be wound around the outermost part. The first notch and the third notch are both arranged on one side of the positive electrode tab along the length direction X, and the second notch and the fourth notch are both arranged on one side of the negative electrode tab along the length direction X, or; The first notch and the third notch are both arranged on the side opposite to the length direction X of the positive electrode tab, and the second notch and the fourth notch are both arranged on the side opposite to the length direction X of the negative electrode tab, or; One of the first notch and the third notch is arranged on one side of the positive electrode tab along the length direction X, and the other is arranged on the side of the positive electrode tab in the opposite direction of the length direction X; one of the second notch and the fourth notch is arranged on one side of the negative electrode tab along the length direction X, and the other is arranged on the side of the negative electrode tab in the opposite direction of the length direction X.

5. The winding core as described in claim 4, characterized in that, wherein... When the positive electrode and the negative electrode are in the unfolded state, their width direction is the Y direction. The positive electrode tab extends in the Y direction, and the negative electrode tab extends in the opposite direction of the Y direction. The openings of the first notch and the fourth notch are both facing in the opposite direction of the Y direction, and the openings of the second notch and the third notch are both facing in the Y direction.

6. The winding core as described in claim 5, characterized in that, The width of the overlap between the positive electrode tab and the positive electrode sheet does not exceed half the width of the positive electrode sheet, and the width of the overlap between the negative electrode tab and the negative electrode sheet does not exceed half the width of the negative electrode sheet.

7. The winding core as described in claim 2, characterized in that, Let the width of the positive electrode tab be a, the width of the second notch be a1, and the width of the third notch be a2, where a ≤ a1 ≤ a2, and a2 is 0.5 mm - 1 mm larger than a.

8. The winding core as described in claim 2, characterized in that, a The width of the negative electrode tab is b. Let the width of the fourth notch be b1 and the width of the first notch be b2. Let b ≤ b1 ≤ b2 and b2 be 0.5 mm - 1 mm larger than b.

9. The winding core as described in claim 1, characterized in that, The core is wound into a roughly circular shape, and the central angles of the positive and negative electrodes are both between 70° and 110°.

10. A cylindrical battery, characterized in that, The device includes a housing and a core as described in any one of claims 1 to 9, the core being housed within the housing, the housing comprising an insulated and sealed positive electrode housing and a negative electrode housing, the positive electrode tab being connected to the positive electrode housing, and the negative electrode tab being connected to the negative electrode housing.

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