Roll core and lithium ion battery

Abstract

The utility model discloses a roll core, which is used for assembling a lithium ion battery and comprises a battery core formed by winding at least one battery core component, and the battery core component comprises a positive plate, a first diaphragm, a negative plate and a second diaphragm which are arranged in a laminated manner; the positive plate and the negative plate are respectively provided with tabs, each tab comprises an extension section, the extension sections extend from the edges of the tabs to one side far away from the tabs, and the tabs are communicated at the tab convergence position; and when the battery cell is in a winding state, the length of the extension section is increased along with the increase of the distance between the tab convergence position and the pole piece connected with the extension section. The utility model also discloses a lithium ion battery using the roll core. The length of the extension section of each tab of the roll core is increased along with the increase of the distance between the tab convergence position and the pole piece connected with the extension section, so that each extension section is enough to extend to the tab convergence position so as to ensure that each tab can be fully communicated, the current transmission efficiency is improved, and the internal resistance and the safety risk of the battery are reduced.

Description

Technical Field

[0001] This utility model relates to the field of lithium-ion battery technology, specifically a winding core and a lithium-ion battery. Background Technology

[0002] Lithium-ion batteries, as a green and environmentally friendly new energy source, have advantages such as high reliability, high safety, small size, and light weight. Therefore, they have been widely used in digital products, electric vehicles, military products, and other fields. With the increasing government support for new energy, the development of lithium-ion batteries is accelerating, and at the same time, the requirements for their performance and safety are becoming increasingly stringent.

[0003] In battery production, perfecting the processing technology of each battery component, especially the tabs of the battery core, has always been a key aspect. In actual tab processing, tabs are mostly obtained by die-cutting from the same template, resulting in tabs of identical size and length. Each tab on the core has welding points, which are welded together and connected to a connecting piece. The connecting piece then connects to a cover plate to form the battery electrodes. However, due to the gaps between the electrode pieces, the welding points of each tab become increasingly distant. When the welding of each tab overlaps, the available welding section on the outer side of the tab decreases, ultimately leading to incomplete welding, reduced connection stability, decreased current transmission efficiency, increased internal resistance of the battery, and a higher risk of short circuits and open circuits, thus increasing safety risks. Utility Model Content

[0004] To overcome the deficiencies in the prior art, this utility model provides a winding core and a lithium-ion battery. The length of the extension segment of each tab of the winding core increases with the increase of the distance between the tab meeting point and the electrode connected to the extension segment, so that each extension segment can extend sufficiently to the tab meeting point, thereby ensuring that each tab can be fully connected, improving current transmission efficiency, and reducing battery internal resistance and safety risks.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is: a core for assembling lithium-ion batteries, comprising:

[0006] A battery cell, wherein the battery cell is wound together from at least one battery cell assembly, the battery cell assembly including a positive electrode plate, a first separator, a negative electrode plate and a second separator stacked together;

[0007] At least two tabs are provided, the positive electrode and the negative electrode are respectively provided with tabs, the tabs include an extension section, the extension section extends from the edge of the electrode to the side away from the electrode, the tabs provided on the positive electrode are connected at the junction of the positive electrode tabs, and the tabs provided on the negative electrode are connected at the junction of the negative electrode tabs.

[0008] When the battery cell is wound, the length of the extension increases as the distance between the tab meeting point and the electrode connected to the extension increases.

[0009] Through the above technical solution, the length of the extension segment of each tab increases with the increase of the distance between the tab meeting point and the electrode connected to the extension segment, so that each extension segment can extend sufficiently to the tab meeting point, thereby ensuring that each tab can be fully connected, improving current transmission efficiency, and reducing battery internal resistance and safety risks.

[0010] Furthermore, the tab on the positive electrode plate is designated as a positive tab, and the tab on the negative electrode plate is designated as a negative tab, with a gap between the positive and negative tabs in a first direction. This gap between the positive and negative tabs prevents interference that could cause a short circuit in the battery.

[0011] Furthermore, both the negative and positive electrodes are divided into a first electrode, a second electrode, ... an nth electrode, and the length of the extension segment increases sequentially from the first electrode to the nth electrode. Fixing the lengths of the first electrode to the nth electrode facilitates mass production.

[0012] Furthermore, an elongated section is provided on the side of the electrode tab away from the electrode tab confluence position, which is used to adjust the position, angle, and intensity of the electrode tab confluence.

[0013] Furthermore, the length L of the electrode tab is set according to the following formula:

[0014]

[0015] In the formula, a n a1 represents the length of the extension segment of the nth electrode ear, c represents the maximum interval between two adjacent negative electrodes ear or two adjacent positive electrodes ear, and L represents the length of the extension segment of the first electrode ear. 正 L represents the width of the positive electrode plate. 负 L represents the width of the negative electrode. 隔 c represents the width of the first or second partition. n L represents the maximum interval between the extension of the nth pole ear and the first pole ear. n Let represent the length of the nth tab, and b represent the length of the extended section of the tab. According to this formula, by measuring the length of the extended section of the first tab, the lengths of the second to nth tabs can be obtained. The formula can be input into a host computer, which can then control the die-cutting machine to cut tabs that meet the requirements according to the actual size of the battery.

[0016] Furthermore, the extension of the first tab is perpendicular to the battery cell, and the tab confluence point is located on the first tab. The tab confluence point needs to have a certain height. By setting the extension of the first tab perpendicular to the battery cell, the shortest tab that meets the preset height can be made, thus saving raw materials.

[0017] Furthermore, the first tab is connected to the outermost negative or positive electrode of the battery cell, and the second to nth tabs are sequentially connected to the inner negative or positive electrode.

[0018] Furthermore, the extended sections of each of the aforementioned tabs are of equal length to maintain the aesthetic appearance of the battery cell.

[0019] A lithium-ion battery, comprising:

[0020] A housing, wherein the housing is provided with an openable and closable cover, and the cover is provided with a pole post;

[0021] The aforementioned core is disposed within the housing;

[0022] A connecting piece, which connects the electrode junction position and the electrode post.

[0023] Furthermore, the tab on the positive electrode plate is a positive tab, and the tab on the negative electrode plate is a negative tab, with a gap between the positive and negative tabs in a first direction. The extension of the first tab is perpendicular to the battery cell, and the tabs converge at the first tab. The first tab is connected to the outermost negative or positive electrode plate of the battery cell, and the second to nth tabs are sequentially connected to the innermost negative or positive electrode plates.

[0024] With the above scheme, the extension of the first electrode, the battery cell, and the extensions of the other electrodes are arranged in multiple triangles, making the structure more stable.

[0025] Furthermore, at least two connecting blocks are provided on the inner sidewall of the housing, and the positive and negative electrodes converge at the connecting blocks respectively. The connecting blocks can enhance the support capacity of the first electrode.

[0026] Based on the above technical solution, the beneficial effects of this utility model are as follows:

[0027] 1. In this application, the length of the extension segment of each tab increases with the increase of the distance between the tab meeting point and the electrode connected to the extension segment, so that each extension segment can extend sufficiently to the tab meeting point, thereby ensuring that each tab can be fully connected, improving current transmission efficiency, and reducing battery internal resistance and safety risks.

[0028] 2. In this application, the electrode tab has an extension section and an extended section. One end of the extension section is connected to the electrode plate, and the other end is used for electrode tab merging. The extended section is connected to the end of the electrode tab used for electrode tab merging, which can be used to adjust the position, angle, and intensity of electrode tab merging.

[0029] 3. When the battery experiences abnormal conditions such as overcharging, over-discharging, or short circuit, the extended section of the tab can provide additional current channels and heat dissipation area, thereby reducing the damage and impact of abnormal conditions on the internal structure of the battery.

[0030] To make the above and other objects, features and advantages of this utility model more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0031] 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.

[0032] Figure 1 This is a schematic diagram of the battery cell assembly in an embodiment of this utility model;

[0033] Figure 2 This is a top view of the winding core placed inside the battery casing in an embodiment of this utility model;

[0034] Figure 3 This is a side view of the core in an embodiment of this utility model.

[0035] The reference numerals in the above figures are as follows: 1. Battery cell; 11. Negative electrode; 12. First separator; 13. Positive electrode; 14. Second separator; 15. Tab; 151. Extension section; 152. Extended section; 153. Negative tab; 154. Positive tab; 2. Housing. Detailed Implementation

[0036] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0037] It should be noted that in the description of this utility model, the terms "first," "second," etc., are used only for descriptive purposes and to distinguish similar objects; there is no order between them, nor should they be construed as indicating or implying relative importance. Furthermore, in the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0038] Example: Combining Figure 1-3 As shown, Embodiment 1 discloses a winding core for assembling a lithium-ion battery, comprising:

[0039] Battery cell components, such as Figure 1 As shown, the battery cell assembly includes a negative electrode 11, a first separator 12, a positive electrode 13, and a second separator 14 stacked together. At least two of the battery cell assemblies are stacked and wound together to form a battery cell 1.

[0040] Each of the negative electrode 11 or positive electrode 13 has a tab 15 welded on it. The tab connected to the negative electrode 11 is a negative tab 153, and the tab connected to the positive electrode 13 is a positive tab 154. Figure 2 As shown, the positive electrode tab 154 and the negative electrode tab 153 are spaced apart in the first direction to avoid mutual interference and short circuit in the battery. It should be noted that, for ease of observation, Figure 2 The width of the positive electrode tab 154 and the negative electrode tab 153 has been enlarged. The actual width of the positive electrode tab 154 and the negative electrode tab 153 is less than or equal to the width of the electrode plate.

[0041] Optionally, the negative electrode 11 or positive electrode 13 and their respective tabs 15 can be integrally formed.

[0042] The tab 15 is divided into an extension section 151 and an extended section 152. In this application, the end of the extension section 151 facing away from the extended section 152 is fixedly connected to the negative electrode 11 or the positive electrode 13. The junction of the extension section 151 and the extended section 152 is a welding point. The welding points of each negative tab 153 overlap and are welded together. Similarly, the welding points of each positive tab 154 overlap and are welded together.

[0043] Because the welding points themselves may have certain stress or defects, the extended section of the tab 15 can provide additional connection area and mechanical support, thereby enhancing the stability and durability of the connection. The extended section of the tab 15 also allows for adjustment of the welding position, angle, and strength of the electrical contacts, making the welding process more flexible. Simultaneously, in the event of abnormal conditions such as overcharging, over-discharging, or short circuits in the battery, the extended section of the tab 15 can provide additional current channels or heat dissipation area, thereby mitigating the damage and impact of these abnormal conditions on the battery's internal structure.

[0044] Optionally, the welding point can also be a binding point or other method for connecting the electrode 15.

[0045] It should be noted that the positive electrode 154 and the negative electrode 153 are each divided into a first electrode, a second electrode, ... an nth electrode. The first electrode is connected to the outermost negative electrode 11 or positive electrode 13 of the battery cell 1, and the second electrode to the nth electrode are connected to the inner negative electrode 11 or positive electrode 13 in sequence.

[0046] In this application, the extension 151 of the first tab is perpendicular to the battery cell 1, and the welding points of each tab 15 overlap at the welding point of the first tab. The welding points of the tabs 15 need to have a certain height to create a gap between the welding point and the battery cell, facilitating subsequent welding. By setting the extension 151 of the first tab perpendicular to the battery cell 1, the shortest tab that meets the preset height can be created. That is, the area a1 of the extension 151 of the first tab is equal to the preset height of the welding point.

[0047] Let c be the maximum interval between two adjacent negative electrodes 153 or two adjacent positive electrodes 154. Figure 2 We can obtain:

[0048] c = L 正 +L 负 +2×L 隔 ;

[0049] In the formula, L 正 L represents the width of the positive electrode plate. 负 L represents the width of the negative electrode. 隔 This represents the width of the first or second partition.

[0050] Let c be the maximum interval between the extension segment 151 of the nth pole ear and the first pole ear. n Since the intervals between adjacent negative electrode tabs 153 or adjacent positive electrode tabs 154 are equal, we can obtain:

[0051] c n = (n-1)c;

[0052] Depend on Figure 3 It can be seen that the extension 151 of the first electrode, the cell 1, and the extensions 151 of the other electrodes form multiple right triangles. By the Pythagorean theorem, we can obtain:

[0053]

[0054] In the formula, a n The length of the extension segment 151 representing the nth pole ear.

[0055] In summary, the length L of the electrode tab should satisfy the following formula:

[0056] L n =a n +b;

[0057] In the formula, L n 'b' represents the length of the nth tab, and 'b' represents the length of the extended section of the tab. In this application, the extended sections 152 of each of the tabs 15 are of equal length to maintain the aesthetic appearance of the cell 1.

[0058] According to the above formula, by determining the length of the extension segment 151 of the first tab, the lengths of the second tab to the nth tab can be obtained. The formula can be input into the host computer, which can then control the die-cutting machine to cut out the tabs that meet the requirements according to the actual size of the battery.

[0059] Compared to the traditional method of using die-cut tabs of identical size and length to weld onto the individual pole pieces of the core, and then overlapping and welding the welding points of the individual tabs together, this method addresses the issue of the welding points of the individual tabs becoming increasingly distant due to the gaps between the pole pieces. Consequently, the closer the tabs are to the edges, the fewer welding ends are available for welding.

[0060] This ultimately leads to incomplete welding, reduced connection stability, decreased current transmission efficiency, increased battery internal resistance, and a higher risk of short circuits and open circuits, thus increasing safety risks.

[0061] The lengths of the extension segments 151 of each tab 15 of the core disclosed in this application increase progressively according to a formula, ensuring that the welding points of each tab 151 can completely overlap and be fully welded, thereby improving current transmission efficiency and reducing battery internal resistance and safety risks. The extended segments can be used to adjust the position, angle, and strength of the welding points, making the welding process more flexible.

[0062] In the above scheme, the extension 151 of the first tab is set perpendicular to the cell 1, which can make the shortest tab that meets the preset height, so as to save raw materials.

[0063] The extension 151 of the first electrode, the battery cell 1, and the extensions 151 of each other electrode are arranged in multiple triangles, making the structure more stable.

[0064] Example 2 discloses a lithium-ion battery, comprising:

[0065] The housing 2 is provided with an openable cover, and the cover is provided with a pole post;

[0066] The aforementioned core is disposed within the housing 2;

[0067] A connecting piece, which connects the welding point and the pole post.

[0068] Two connecting blocks are provided on the inner wall of the housing 2, and the welding points of the positive electrode tab 154 and the negative electrode tab 153 are respectively welded to the connecting blocks. The extension section 151 of the first electrode tab is welded to the connecting blocks, which can enhance the support capacity of the first electrode tab.

[0069] This utility model uses specific embodiments to illustrate the principle and implementation of the utility model. The above description of the embodiments is only for the purpose of helping to understand the method and core idea of ​​the utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the utility model. Therefore, the content of this specification should not be construed as a limitation of the utility model.

Claims

1. A winding core for assembling lithium-ion batteries, characterized in that, include: A battery cell, wherein the battery cell is wound together from at least one battery cell assembly, the battery cell assembly including a positive electrode plate, a first separator, a negative electrode plate and a second separator stacked together; At least two tabs are provided, the positive electrode and the negative electrode are respectively provided with tabs, the tabs include an extension section, the extension section extends from the edge of the electrode to the side away from the electrode, the tabs provided on the positive electrode are connected at the junction of the positive electrode tabs, and the tabs provided on the negative electrode are connected at the junction of the negative electrode tabs. When the battery cell is wound, the length of the extension increases as the distance between the tab meeting point and the electrode connected to the extension increases.

2. The winding core as described in claim 1, characterized in that, The tab on the positive electrode plate is designated as the positive tab, and the tab on the negative electrode plate is designated as the negative tab. The positive tab and the negative tab are spaced apart in a first direction.

3. The winding core as described in claim 2, characterized in that, Both the negative electrode tab and the positive electrode tab are divided into a first electrode tab, a second electrode tab, ... an nth electrode tab, and the length of the extension segment increases in the order of the first electrode tab to the nth electrode tab.

4. The winding core as described in claim 3, characterized in that, The electrode tab is further provided with an extended section on the side opposite to the electrode tab confluence position.

5. The winding core as described in claim 4, characterized in that, The length L of the electrode tab is set according to the following formula: ； In the formula, Represents the length of the extension segment of the nth pole ear. represents the length of the extension segment of the first electrode ear, and c represents the maximum interval between two adjacent negative electrodes or two adjacent positive electrodes. Represents the width of the positive electrode plate. Represents the width of the negative electrode plate. This represents the width of the first or second partition. This represents the maximum interval between the extension of the nth pole ear and the first pole ear. represents the length of the nth electrode tab, and b represents the length of the extended section of the electrode tab.

6. The winding core as described in any one of claims 3-5, characterized in that, The extension of the first tab is perpendicular to the battery cell, and the tabs converge at the first tab.

7. The winding core as described in claim 6, characterized in that, The first tab is connected to the outermost negative or positive electrode of the battery cell, and the second to nth tabs are connected to the inner negative or positive electrode in sequence.

8. The winding core as described in claim 6, characterized in that, The extended sections of each of the aforementioned tabs are of equal length.

9. A lithium-ion battery, characterized in that, include: A housing, wherein the housing is provided with an openable and closable cover, and the cover is provided with a pole post; The winding core according to any one of claims 2-8 is disposed within the housing; A connecting piece, which connects the electrode junction position and the electrode post.

10. The lithium-ion battery as described in claim 9, characterized in that, At least two connecting blocks are provided on the inner sidewall of the housing, and the positive and negative electrodes converge at the connecting blocks respectively.

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