Cylindrical battery with expansion adhesive tape
By wrapping the expansion tape around the outer periphery of the roll core and ensuring that it expands and fills the gap after the electrolyte contacts, the short circuit problem caused by aluminum foil folding is solved, and the safety of the battery and structural tolerance compatibility are achieved.
Patent Information
- Application Number
- CN202421365994.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-14
- Publication Date
- 2025-07-25
- Estimated Expiration
- 2034-06-14
AI Technical Summary
In the prior art, the folding of the aluminum foil wound with the battery is prone to contact with the outer shell and leads to a risk of short circuit, and it is difficult to avoid secondary problems in the existing structural tolerance design.
A cylindrical battery with expansion tape is designed, which is wrapped around the outer periphery of the core and its top is flush or higher than the top of the diaphragm before expansion, ensuring that the gap between the core and the insulating cap expands after the electrolyte contacts, forming a double protection.
It effectively avoids the risk of short-circuiting of aluminum foil to the outer shell, conforms to the existing structural tolerance design, does not cause new secondary problems, and can withstand high temperatures of large-scale charge and discharge.
Smart Images
Figure CN223156051U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of batteries, and specifically, to a cylindrical battery with an expansion tape. Background Art
[0002] Batteries or battery packs are crucial for powering many daily-use electronic devices. A battery composed of a core formed by a winding method is called a wound battery. It is widely favored in the energy storage field for its large starting current, good seismic resistance, excellent high and low temperature performance, and long cycle service life.
[0003] Currently, full-tab positive and negative electrodes are commonly used in batteries. That is, when coating the positive electrode paste on the positive electrode current collector (usually aluminum foil), a part of the area at one end edge is reserved without coating the paste (positive electrode bare foil area), and when coating the negative electrode paste on the negative electrode current collector (usually copper foil), a part of the area at one end edge is reserved without coating the paste (negative electrode bare foil area). After the positive electrode sheet, negative electrode sheet, and separator are wound to form a core winding body, it is then flattened. The foil body in the positive electrode bare foil area forms the end face of the tab position of the positive electrode (i.e., the positive end face), and the foil body in the negative electrode bare foil area forms the end face of the tab position of the negative electrode (i.e., the negative end face). The end face of the tab position needs to be welded to the bus bar so that the current of the battery can be output from the bus bar.
[0004] Generally, for the electrical insulation of wound batteries, insulation between the core and the battery outer casing, as well as between the core and the end cap, needs to be achieved. However, after the conventional full-tab battery core is flattened, although there is an insulating cap for protection, there is still a risk of short circuit due to the outer aluminum foil folding and contacting the outer casing.
[0005] Therefore, a design of a cylindrical battery with an expansion tape is needed, which can reduce the risk of short circuit caused by the aluminum foil folding and contacting the outer casing, and conform to the existing structural tolerance design without generating new secondary problems. Summary of the Utility Model
[0006] The purpose of the utility model is to provide a cylindrical battery with an expansion tape. The cylindrical battery with an expansion tape of the utility model can reduce the risk of short circuit caused by the aluminum foil folding and contacting the outer casing, and conform to the existing structural tolerance design without generating new secondary problems.
[0007] The utility model provides a cylindrical battery with an expansion tape, and the cylindrical battery includes:
[0008] An outer casing and a core accommodated in the outer casing;
[0009] The core is obtained by winding, and then flattening a positive electrode sheet, a negative electrode sheet and a separator. The core includes a positive electrode end face and a negative electrode end face. An expansion tape is wound around the outer periphery of the core. At least at the positive electrode end of the core, before the expansion tape expands, the top of the expansion tape is flush with or higher than the top of the separator.
[0010] In one embodiment, the height H1 by which the top of the expansion tape exceeds the top of the separator is 0 mm to 1 mm, preferably 0.1 mm to 0.9 mm, more preferably 0.2 mm to 0.8 mm, and further preferably 0.3 mm to 0.8 mm.
[0011] In one embodiment, after the expansion tape expands, the top of the expansion tape is flush with the positive electrode end face.
[0012] In one embodiment, the expansion tape separates the positive electrode end of the core from the outer casing.
[0013] In one embodiment, the positive electrode end of the core includes a tapered section, and the expansion tape fills the gap between the tapered section and the outer casing.
[0014] In one embodiment, the width H of the expansion tape is 60 mm to 65 mm, preferably 61 mm to 65 mm, more preferably 62 mm to 64 mm, and further preferably 62.8 mm to 63.3 mm.
[0015] In one embodiment, the bottom of the expansion tape is higher than the bottom of the separator, and the height H2 by which it exceeds is 1 mm to 4 mm, preferably 1.5 mm to 3.5 mm, more preferably 2 mm to 3 mm, and further preferably 2.5 mm.
[0016] In one embodiment, an insulating cap is further provided at the top of the core.
[0017] In one embodiment, the insulating cap at least partially covers the expansion tape.
[0018] In one embodiment, the insulating cap is a flat sheet type, and the expanded expansion tape abuts against the insulating cap.
[0019] In one embodiment, after the expansion tape contacts the electrolyte, it expands in the three-dimensional directions of length, width and thickness.
[0020] In one embodiment, the positive electrode current collector of the core is an aluminum foil, and the ratio of the exposed height of the aluminum foil to the height of the core is 1:1 to 1:200.
[0021] In one embodiment, before the core is flattened, the top of the expansion tape is located between the top of the diaphragm and 0.8 mm above the top of the diaphragm. The flattening process will stop at 0.8 mm above the top of the diaphragm, and there is no interference with the position of the expansion tape.
[0022] Additional features and advantages of the present utility model will be set forth in the following detailed description, and will be apparent to those skilled in the art from that description, or recognized by practicing the embodiments as described in the following description, the claims, and the appended Figure 1 description.
[0023] It should be understood that the above general description and the following detailed description are exemplary and are only intended to provide an overview or framework for understanding the nature and characteristics of the present utility model and the appended claims. As a non-limiting example, various features of the present utility model can be combined with each other according to the following embodiments. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] To better understand the above and other objects, features, advantages, and functions of the present utility model, reference may be made to the preferred embodiments shown in the accompanying drawings. The same reference numerals in the drawings refer to the same components. Those skilled in the art should understand that the drawings are intended to schematically illustrate the preferred embodiments of the present utility model and have no limiting effect on the scope of the present utility model. The components in the drawings are not drawn to scale.
[0025] Figure 1 Schematic diagram of the core structure in the prior art (before flattening);
[0026] Figure 2 Schematic diagram of the core structure according to a preferred embodiment of the present utility model (before flattening);
[0027] Figure 3 Schematic diagram of the core structure in the prior art (after flattening);
[0028] Figure 4 Schematic diagram of the core structure according to a preferred embodiment of the present utility model (after flattening);
[0029] Figure 5 Schematic diagram of the core structure according to another preferred embodiment of the present utility model (after flattening).
[0030] Reference Numerals:
[0031] 1 Positive electrode terminal;
[0032] 11 Positive electrode end face;
[0033] 12 Tapered section;
[0034] 2 Negative electrode terminal;
[0035] 21 Negative extreme surface;
[0036] 3 Diaphragm;
[0037] 4 Expansion tape;
[0038] 5 Current collector;
[0039] 6 Insulating cover;
[0040] h1 is the height that the top of the diaphragm is higher than the top of the expansion tape in the prior art;
[0041] h2 is the height that the bottom of the expansion tape is higher than the bottom of the diaphragm in the prior art;
[0042] h is the width of the expansion tape in the prior art;
[0043] H1 is the height that the top of the expansion tape is higher than the top of the diaphragm in the present invention;
[0044] H2 is the height that the bottom of the expansion tape is higher than the bottom of the diaphragm in the present invention;
[0045] H is the width of the expansion tape in the present invention. Detailed implementation manners
[0046] Now referring to the accompanying drawings, the detailed implementation manners of the present invention will be described in detail. What is described here is only the preferred implementation manner according to the present invention, and those skilled in the art can think of other ways that can implement the present invention on the basis of the preferred implementation manner, and those other ways also fall within the scope of the present invention.
[0047] Unless otherwise clearly stated, it is not intended to require a specific orientation for any device. Therefore, in the case where the order or direction of individual components is not actually described in any device claim, or where the steps are not specifically limited to a specific order in the claims or the specification or the specific order or direction of the components of the device is not described, no inference of its order or direction is intended in any aspect.
[0048] Figures 1 to 5 A cylindrical battery with an expansion tape according to the present invention is shown respectively. First of all, it should be noted that the directional terms and position terms in the present invention should be understood as relative directions and positions, rather than absolute directions and positions. The directional terms and position terms in the present invention can be explained with reference to Figures 1 to 5 the exemplary structure shown.
[0049] The inventor found in the practice of production and research that the electrical insulation of the wound battery needs to achieve the insulation between the wound core and the battery housing, and the insulation between the wound core and the end cap. However, in the prior art, such asFigure 1 (Before flattening) and Figure 3 (After flattening) as shown, a generally provided cylindrical battery includes a housing and a wound core accommodated in the housing, wherein the wound core is obtained by winding a positive electrode sheet, a negative electrode sheet, and a separator 3 and flattening both ends, the wound core includes a positive electrode end face 11 and a negative electrode end face 21, an expansion tape 4 is wound around the outer periphery of the wound core, and the top of the expansion tape 3 is significantly lower than the top of the separator 3. The inventors have found that such a design has the following problems: After the battery core is flattened, although protected by an insulating cap, there is still a risk of short circuit due to the outer aluminum foil folding over and contacting the housing. Therefore, a design of a cylindrical battery with an expansion tape is needed that can solve the risk of short circuit caused by the aluminum foil folding over and contacting the housing, and conforms to the existing structural tolerance design without generating new secondary problems.
[0050] Now referring to Figure 2 (Before flattening) and Figure 4 (After flattening), according to the first aspect of the present invention, a cylindrical battery is provided. The cylindrical battery includes: a housing and a wound core accommodated in the housing; wherein the wound core is obtained by winding a positive electrode sheet, a negative electrode sheet, and a separator 3 and flattening, the wound core includes a positive electrode end face 11 and a negative electrode end face 21, an expansion tape 4 is wound around the outer periphery of the wound core, and at least at the positive electrode end 1 of the wound core, before the expansion tape 4 expands, the top of the expansion tape 4 is flush with or higher than the top of the separator 3. The inventors have found that such a design can well avoid the risk of short circuit caused by the aluminum foil folding over and contacting the housing.
[0051] The inventors have found through multiple experiments that when the height H1 by which the top of the expansion tape 4 exceeds the top of the separator 3 is 0 mm (i.e., the top of the expansion tape 4 is flush with the top of the separator 3) to 1 mm, preferably 0.1 mm to 0.9 mm, more preferably 0.2 mm to 0.8 mm, and further preferably 0.3 mm to 0.8 mm, the short circuit protection effect is better. Specifically, when the above-mentioned wound core is immersed in the electrolyte, the expansion tape 4 will expand in the three dimensions of length, width, and thickness, and can well fill the gap between the wound core and the insulating cap 6, and both the expansion tape 4 and the insulating cap 6 are made of soft materials and will not undergo hard extrusion. At the same time, the expanded expansion tape 4 and the insulating cap 6 form a double protection, completely covering the entire positive electrode end 1 without contacting the steel shell, and being able to withstand the high temperature of high-rate charge and discharge. In addition, the design of the expansion tape 4 of the present invention conforms to the existing structural tolerance design and will not generate new secondary problems.
[0052] As another preferred embodiment, after the expansion tape 4 expands, the top of the expansion tape 4 is flush with the positive extreme surface 11, and the short-circuit protection effect is better. Among them, the expansion tape 4 separates the positive extreme 1 of the core and the outer casing. As a further preference, the positive extreme 1 of the core includes a tapered section 12, and the expansion tape 4 fills the gap between the tapered section 12 and the outer casing.
[0053] Generally, the width H of the expansion tape 4 needs to match the height of the core of the cylindrical battery. For example, as Figure 2 , Figure 4 and Figure 5 shown, in one embodiment, the width H of the expansion tape 4 is 60 mm to 65 mm, preferably 61 mm to 65 mm, more preferably 62 mm to 64 mm, and further preferably 62.8 mm to 63.3 mm.
[0054] Please further refer to Figure 2 , Figure 4 and Figure 5 , generally, the bottom of the expansion tape 4 is higher than the bottom of the separator 3, and the present invention does not require special limitation on this. As long as the bottom of the core does not short-circuit and the battery can be used normally. As a preferred embodiment of the present invention, the bottom of the expansion tape 4 is higher than the bottom of the separator 3, and the exceeded height H2 is 1 mm to 4 mm, preferably 1.5 mm to 3.5 mm, more preferably 2 mm to 3 mm, and further preferably 2.5 mm.
[0055] In addition, please refer to Figure 5 , as a further preferred embodiment, an insulating cap 6 is further provided at the top of the core. In one embodiment, the insulating cap 6 is made of an insulating material. As a preferred embodiment, the insulating cap 6 at least partially covers the expansion tape 4. As a preferred embodiment, the insulating cap 6 is a flat sheet type, and the expanded expansion tape 4 abuts against the insulating cap 6.
[0056] At the same time, in one embodiment, the expansion tape 4 is also made of an insulating material. As a preferred embodiment, after the expansion tape 4 contacts the electrolyte, it expands in the three-dimensional directions of length, width, and thickness.
[0057] Please continue to refer to Figure 2 , Figure 4 and Figure 5 , as a preferred embodiment, the positive current collector of the core is aluminum foil. In order to achieve the technical effect of avoiding short circuit, the ratio of the exposed height of the aluminum foil to the core height is 1:1 to 1:200.
[0058] In addition, for the flattening process, if the expansion tape 4 interferes with the flattening head during the flattening process, the expansion tape 4 will be kneaded into it, and debris will be kneaded into the positive end face 11, resulting in problems such as poor welding, short circuit, and excessive resistance between the bus bar 5 and the positive end face 11. Therefore, to avoid the above problems, during the flattening process, before the core is flattened, the top of the expansion tape 4 is located between the top of the separator 3 and 0.8 mm above the top of the separator 3. The flattening process will stop when it reaches 0.8 mm above the top of the separator 3, and there will be no interference with the position of the expansion tape 4. Moreover, when the distance from the expansion tape 4 to the flattening surface (positive end face 11) is 0 mm to 0.8 mm, especially 0.8 mm, when the core is immersed in the electrolyte, the expansion tape 4 will expand in the three dimensions of length, width, and thickness, and can well fill the gap between the core and the insulating cap 6. And both the expansion tape 4 and the insulating cap 6 are made of soft materials and will not cause hard extrusion.
[0059] In some embodiments, for the positive end 1 of the core, as Figure 1 shown, a tapered section 12 is formed in the flattening section. Preferably, the top of the expanded expansion tape 4 is flush with the positive end face 11. The expanded expansion tape 4 can fill the gap between the tapered section 12 and the outer housing. Or rather, the expanded expansion tape 4 fills the gap between the positive end 1 of the core and the outer housing.
[0060] In some embodiments, in the case where the insulating cap 6 is provided, the expanded expansion tape 4 and the insulating cap 6 form a double protection, completely covering the entire positive end 1 without contacting the steel shell, and being able to withstand the high temperature of high-rate charge and discharge. In some embodiments, the insulating cap 6 can be omitted. In some embodiments, the insulating cap 6 can be set in a flat sheet shape (flat sheet type), and the expanded expansion tape 4 abuts against the insulating cap 6. In addition, the design of the expansion tape 4 in the present invention conforms to the existing structural tolerance design and will not cause new secondary problems.
[0061] The above description of the various embodiments of the present invention is provided for a person of ordinary skill in the relevant art for the purpose of description. It is not intended to exclude or limit the present disclosure to a single disclosed embodiment. As above, a person of ordinary skill in the art taught above will understand the various alternatives and modifications of the present disclosure. Therefore, although some alternative embodiments are specifically described, a person of ordinary skill in the art will understand or relatively easily develop other embodiments. The present disclosure aims to include all such alternatives, modifications, and variations, as well as other embodiments that fall within the spirit and scope of the present disclosure described above.
Claims
1. A cylindrical battery, characterized in that, Comprising: An outer casing and a wound core accommodated in the outer casing; Wherein the wound core is obtained by winding and flattening a positive electrode sheet, a negative electrode sheet and a separator (3), the wound core includes a positive electrode end face (11) and a negative electrode end face (21), an expansion tape (4) is wound around the outer periphery of the wound core, and at least at the positive electrode end (1) of the wound core, before the expansion tape (4) expands, the top of the expansion tape (4) is flush with or higher than the top of the separator (3).
2. The cylindrical battery according to claim 1, characterized in that: The height H1 by which the top of the expansion tape (4) exceeds the top of the separator (3) is 0 mm to 1 mm.
3. The cylindrical battery according to claim 2, characterized in that: The height H1 by which the top of the expansion tape (4) exceeds the top of the separator (3) is 0.1 mm to 0.9 mm.
4. The cylindrical battery according to claim 2, wherein: The height H1 by which the top of the expansion tape (4) exceeds the top of the separator (3) is 0.2 mm to 0.8 mm.
5. The cylindrical battery according to claim 2, wherein: The height H1 by which the top of the expansion tape (4) exceeds the top of the separator (3) is 0.3 mm to 0.8 mm.
6. The cylindrical battery according to claim 1, characterized in that: After the expansion tape (4) expands, the top of the expansion tape (4) is flush with the positive electrode end face (11).
7. The cylindrical battery according to claim 6, characterized in that: The expansion tape (4) separates the positive electrode end (1) of the wound core from the outer casing.
8. The cylindrical battery according to claim 6, wherein: The positive electrode end (1) of the wound core includes a tapered section (12), and the expansion tape (4) fills the gap between the tapered section (12) and the outer casing.
9. The cylindrical battery according to claim 1, characterized in that: The width H of the expansion tape (4) is 60 mm to 65 mm.
10. The cylindrical battery according to claim 9, characterized in that: The width H of the expansion tape (4) is 61 mm to 65 mm.
11. The cylindrical battery according to claim 9, wherein: The width H of the expansion tape (4) is 62 mm to 64 mm.
12. The cylindrical battery according to claim 9, characterized in that: The width H of the expansion tape (4) is 62.8 mm to 63.3 mm.
13. The cylindrical battery according to claim 1, wherein: The bottom of the expansion tape (4) is higher than the bottom of the separator (3), and the height H2 by which it exceeds is 1 mm to 4 mm.
14. The cylindrical battery according to claim 13, wherein: The bottom of the expansion tape (4) is higher than the bottom of the separator (3), and the height H2 by which it exceeds is 1.5 mm to 3.5 mm.
15. The cylindrical battery according to claim 13, wherein: The bottom of the expansion tape (4) is higher than the bottom of the separator (3), and the height H2 by which it exceeds is 2 mm to 3 mm.
16. The cylindrical battery according to claim 13, wherein: The bottom of the expansion tape (4) is higher than the bottom of the separator (3), and the height H2 by which it exceeds is 2.5 mm.
17. The cylindrical battery according to claim 1, wherein: An insulating cap (6) is further provided at the top of the wound core.
18. The cylindrical battery according to claim 17, wherein: The insulating cap (6) at least partially covers the expansion tape (4).
19. The cylindrical battery according to claim 17, wherein: The insulating cap (6) is a flat sheet type, and the expanded expansion tape (4) abuts against the insulating cap (6).
20. The cylindrical battery according to any one of claims 1-18, characterized in that: After the expansion tape (4) contacts the electrolyte, it expands in the three-dimensional directions of length, width and thickness.
21. The cylindrical battery according to any one of claims 1-18, characterized in that: The positive electrode current collector of the wound core is an aluminum foil, and the ratio of the exposed height of the aluminum foil to the height of the wound core is 1:1 to 1:
200.
22. The cylindrical battery according to any one of claims 1-18, characterized in that: Before the wound core is flattened, the top of the expansion tape (4) is located between the top of the separator (3) and 0.8 mm above the top of the separator (3), and the flattening process will stop at 0.8 mm above the top of the separator (3), and there is no position interference with the expansion tape (4).