Tab structure and battery

Abstract

The utility model relates to the technical field of lithium ion batteries, and discloses a tab structure and a battery. The tab structure comprises a welding section and an exposed section, wherein the welding section is welded on a current collector of a pole piece; the exposed section is exposed out of the current collector; the welding section and the exposed section are connected into a whole to form a step-shaped metal belt; the width D2 of the welding section is larger than or equal to the width D1 of the exposed section, and the thickness T2 of the welding section is larger than the thickness T1 of the exposed section. According to the tab structure provided by the utility model, the cross sectional area of the tab at the welding section is relatively larger, and the internal resistance is smaller, so that the Joule heat generated in the quick charging and quick discharging process is smaller, and the temperature rise of the battery cell in the quick charging and quick discharging process is also reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium-ion batteries, in particular to a tab structure and a battery. Background Art

[0002] The tab is a core component of lithium-ion batteries. During the charge / discharge process of lithium-ion batteries, the lithium-ion batteries will generate Joule heat at the tab, and the generated Joule heat will cause the temperature of the lithium-ion batteries to rise; especially when the battery cells are fast charged and discharged, a large amount of Joule heat will inevitably be generated, causing the battery cell temperature to rise too quickly. This is why electronic products will "get hot" when fast charged and discharged.

[0003] With the continuous advancement of technology, people's demands for the performance of electronic products are getting higher and higher, and the demand for the charging / discharging performance of battery cells is also increasing. For example, the fast charging power of mobile phones on the market has exceeded 200W; and for electronic products or user terminals, while improving performance (such as longer battery life and faster charging speed, etc.), they also need to take into account product safety and user experience (such as no overheating during use).

[0004] Therefore, under the premise of ensuring the performance of the battery, reducing the temperature rise of the battery cell during the fast charging and discharging process as much as possible to meet the demand of electronic products not to get hot when used has become a technical problem that needs to be solved urgently in this field.

[0005] The above information is presented as background information only to assist with an understanding of the present disclosure and is not a determination or admission that any of the above may be applicable as prior art with respect to the present disclosure. Utility Model Content

[0006] The purpose of the present invention is to provide a tab structure and a battery to solve or at least partially solve the technical problems existing in the prior art.

[0007] To achieve this purpose, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a tab structure comprising a welding section for welding to a current collector of a pole piece and an exposed section exposed outside the current collector; the welding section and the exposed section are connected as one body to form a stepped metal strip;

[0009] The width D2 of the welding section is greater than or equal to the width D1 of the exposed section, and the thickness T2 of the welding section is greater than the thickness T1 of the exposed section.

[0010] Optionally, the exposed section and the welding section are welded or integrally formed, and the metal strip is a nickel strip or a copper-nickel-plated strip.

[0011] Optionally, the exposed section is connected to the first end of the welding section;

[0012] One side of the welding section in the thickness direction is coplanar with one side of the exposed section in the thickness direction;

[0013] A portion of the first end surface of the welding section exposed outside the exposed section is formed as a step surface, and the step surface connects the other side of the welding section in the thickness direction and the other side of the exposed section in the thickness direction.

[0014] Optionally, the tab structure further includes tab glue connected to the first end of the welding segment.

[0015] Optionally, the tab glue is arranged around the exposed section, and a portion of the tab glue is connected to the step surface.

[0016] Optionally, T2 / T1 is 3 to 1.1 to avoid a large difference in thickness between the exposed section and the welding section, which would increase the difficulty of producing the tab.

[0017] Optionally, T1 is 0.06-0.2 mm, and T2 is 0.08-0.25 mm.

[0018] Optionally, D2 / D1 is 1 to 3; appropriately increasing the width of D2 helps to reduce the internal resistance of the welding section, reduce temperature rise, and increase welding reliability. However, when D2 is too large, welding power consumption increases, and it occupies electrode space, which will lead to a decrease in energy density.

[0019] Optionally, D1 is 1 to 10 mm, and D2 is 1 to 10 mm.

[0020] In a second aspect, the present invention further provides a battery, comprising a pole core and a pole tab structure electrically connected to the pole core, wherein the pole tab structure adopts the pole tab structure described above.

[0021] Optionally, the battery is a lithium-ion battery.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The use of the tab structure of the present invention makes the cross-sectional area of ​​the tab in the welding section relatively larger and the internal resistance smaller. In this way, the Joule heat generated during fast charging and discharging is smaller, and the temperature rise of the battery cell during fast charging and discharging is also reduced.

[0024] The present invention has other features and advantages, which will be apparent from the accompanying drawings and subsequent detailed descriptions incorporated herein, or will be described in detail in the accompanying drawings and subsequent detailed descriptions incorporated herein, which together serve to explain the specific principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 This is a front view of a tab structure provided by an embodiment of the present utility model.

[0027] Figure 2 yes Figure 1 A left view of a tab structure.

[0028] In the figure: 10, welding section; 20, exposed section; 101, step surface; 30, ear glue. DETAILED DESCRIPTION

[0029] In order to explain in detail the possible application scenarios, technical principles, specific solutions that can be implemented, and the purpose and effects of this application, the following is a detailed description of the specific embodiments listed in conjunction with the accompanying drawings. The embodiments described herein are only used to more clearly illustrate the technical solutions of this application and are therefore only examples and are not intended to limit the scope of protection of this application.

[0030] References to "embodiments" herein mean that the specific features, structures, or characteristics described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the word "embodiment" in various places in the specification does not necessarily refer to the same embodiment, nor does it particularly limit its independence or relevance to other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the various technical features mentioned in the embodiments can be combined in any manner to form a corresponding implementable technical solution.

[0031] Unless otherwise defined, the technical terms used herein have the same meanings as those generally understood by those skilled in the art to which this application belongs; the use of relevant terms herein is only for describing specific embodiments and is not intended to limit this application.

[0032] In the description of this application, the term "and / or" is used to describe a logical relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A exists, B exists, and both A and B exist. In addition, the character " / " in this document generally indicates that the objects before and after are in a logical "or" relationship.

[0033] In this application, terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual quantity, priority or sequence relationship between these entities or operations.

[0034] Without further limitations, in this application, the words "include", "comprise", "have" or other similar expressions used in the sentences are intended to cover non-exclusive inclusion. These expressions do not exclude the presence of additional elements in the process, method or product including the elements, so that the process, method or product including a series of elements may include not only those defined elements, but also other elements not explicitly listed, or elements inherent to such process, method or product.

[0035] Consistent with the understanding in the Examination Guidelines, in this application, expressions such as "greater than," "less than," and "exceed" are understood to exclude the number itself; expressions such as "above," "below," and "within" are understood to include the number itself. Furthermore, in the description of the embodiments of this application, "multiple" means more than two (including two), and similar expressions related to "multiple" are also understood in this manner, such as "multiple groups," "multiple times," etc., unless otherwise specifically defined.

[0036] In the description of the embodiments of the present application, the space-related expressions used, such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "vertical", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or position relationship based on the orientation or position relationship shown in the specific embodiments or drawings, and are only for the convenience of describing the specific embodiments of the present application or facilitating the reader's understanding, and do not indicate or imply that the device or component referred to must have a specific position, a specific orientation, or be constructed or operated in a specific orientation. Therefore, it should not be understood as a limitation on the embodiments of the present application.

[0037] Unless otherwise expressly specified or limited, in the description of the embodiments of the present application, the terms "installed", "connected", "connected", "fixed", "set", etc. used should be understood in a broad sense. For example, the "connection" can be a fixed connection, a detachable connection, or an integrated setting; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For those skilled in the art of the present application, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0038] Example 1:

[0039] See also Figure 1 and Figure 2 , Figure 1 This is a front view of a tab structure provided by an embodiment of the utility model. Figure 2 yes Figure 1 A left view of a tab structure.

[0040] The tab structure includes a welding section 10 for welding to the current collector of the pole piece and an exposed section 20 exposed outside the current collector; the welding section 10 and the exposed section 20 are connected into one body to form a stepped metal belt.

[0041] In this embodiment, Figure 1 The horizontal direction is the width direction, Figure 2 Horizontal (or Figure 1 The direction perpendicular to the paper is the thickness direction. Figure 1 As shown, the width D2 of the welding section 10 is greater than or equal to the width D1 of the exposed section 20; Figure 2 As shown, the thickness T2 of the welded section 10 is greater than the thickness T1 of the exposed section 20. As a preferred embodiment, in this embodiment, the value range of T1 is 0.06-0.2 mm, the value range of T2 is 0.08-0.25 mm, and the value range of T2 / T1 is 3-1.1; the value range of D1 is 1-10 mm, the value range of D2 is 1-10 mm, and the value range of D2 / D1 is 1-3.

[0042] The metal strip uses a thicker welding section 10 and a thinner exposed section 20, which increases the cross-sectional area of ​​the tab in the welding section 10 and reduces the internal resistance. Therefore, the Joule heat generated during the rapid charge and discharge of the battery is reduced, thereby reducing the heat generation of the battery and the temperature rise.

[0043] Specifically, using the tab structure provided in this embodiment, according to the formula:

[0044] Joule heat Q = I 2 Rt, internal resistance R = ρ * L / S, where cross-sectional area S = tab thickness * tab width;

[0045] Since the thickness T2 of the welding section 10 is greater than the thickness T1 of the exposed section 20, and the width D2 of the welding section 10 is the same as the width D1 of the exposed section 20, the cross-sectional area of ​​the tab in the welding section is larger and the internal resistance is smaller, so the Joule heat generated during fast charging and discharging is smaller.

[0046] Specifically, the exposed section 20 and the welding section 10 are welded or integrally formed.

[0047] The exposed section 20 and the welding section 10 can be connected by conventional means in the art, that is, the two are connected into one by laser welding;

[0048] As a better implementation method, Figure 2 As shown, the exposed section 20 is connected to the first end of the welding section 10;

[0049] One side of the welding section 10 in the thickness direction is coplanar with one side of the exposed section 20 in the thickness direction;

[0050] The portion of the first end surface of the welding section 10 exposed outside the exposed section 20 is formed as a step surface 101 , which connects the other side of the welding section 10 in the thickness direction and the other side of the exposed section 20 in the thickness direction.

[0051] If the welding section 10 and the exposed section 20 are formed as one piece, a portion of the metal strip can be removed from the metal strip profile by laser etching or other related means to form a stepped metal strip, such as Figure 2 As shown, this can also save the laser welding step, reduce the risk of cold welding or incomplete welding, and improve product yield.

[0052] Specifically, the tab structure further includes tab glue 30 connected to the first end of the welding section 10. The tab glue 30 is a sealing strip used to encapsulate the tab structure. During encapsulation, the tab glue 30 is coated on the connection between the welding section 10 and the exposed section 20 to achieve a sealed package for the battery. Preferably, the tab glue 30 is arranged around the exposed section 20, and a portion of the tab glue 30 is connected to the step surface 101.

[0053] In addition to reducing the internal resistance, the stepped structure of the metal strip, i.e., the stepped structure formed at the connection between the exposed section 20 and the welding section 10, can also facilitate the packaging operation of the tab glue 30, making the control more accurate and the packaging structure more stable.

[0054] Specifically, when encapsulating the tab glue 30, the step surface 101 can be used as a limiting surface or a positioning surface. Because the welding section 10 is the part embedded in the battery, and the exposed section 20 needs to extend outside the battery, the tab glue 30 can be encapsulated around the exposed section 20, which reduces the precision requirement for controlling the glue. The excess glue can flow into the step surface 101 or the inner groove formed by the step surface 101 and the battery shell. This can further fix the tab structure and enhance the stability of the tab structure.

[0055] In summary, the tab structure provided in this embodiment allows the tab to have a relatively larger cross-sectional area in the welding section 10 and a smaller internal resistance. In this way, the Joule heat generated during fast charging and discharging is smaller, and the temperature rise of the battery cell during fast charging and discharging is also reduced.

[0056] Example 2:

[0057] This embodiment provides a battery comprising a core and a tab for electrically connecting to the core, wherein the tab adopts the tab structure as described in Example 1. Since the tab structure has been described in detail in Example 1, it will not be repeated in this embodiment.

[0058] In this embodiment, the battery is a lithium-ion battery; specifically, the metal strip of the positive electrode tab is an aluminum strip, and the metal strip of the negative electrode tab is preferably a nickel strip or a copper-plated nickel strip.

[0059] In summary, the battery provided in this embodiment uses a tab structure that generates less Joule heat during fast charging and discharging, thereby minimizing the temperature rise of the battery cell during fast charging and discharging, and meeting the requirement that electronic products do not overheat when used.

[0060] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A tab structure comprising a welding section (10) for welding to a current collector of a pole piece and an exposed section (20) exposed outside the current collector; characterized in that: The welding section (10) and the exposed section (20) are connected into one body to form a stepped metal strip; The width D2 of the welding section (10) is greater than or equal to the width D1 of the exposed section (20), and the thickness T2 of the welding section (10) is greater than the thickness T1 of the exposed section (20).

2. The tab structure according to claim 1, characterized in that: The exposed section (20) and the welding section (10) are welded or integrally formed, and the metal strip is a nickel strip or a copper-nickel-plated strip.

3. The tab structure according to claim 2, characterized in that: The exposed section (20) is connected to the first end of the welding section (10); One side of the welding section (10) in the thickness direction is coplanar with one side of the exposed section (20) in the thickness direction; The portion of the first end surface of the welding section (10) exposed outside the exposed section (20) is formed into a step surface (101), and the step surface (101) is connected to the other side of the welding section (10) in the thickness direction and the other side of the exposed section (20) in the thickness direction.

4. The tab structure according to claim 3, characterized in that: The tab structure further includes tab glue (30) connected to the first end of the welding section (10).

5. The tab structure according to claim 4, characterized in that: The tab glue (30) is arranged around the exposed section (20), and a portion of the tab glue (30) is connected to the step surface (101).

6. A tab structure according to any one of claims 1 to 5, characterized in that: T2 / T1 is 3 to 1.

1.

7. The tab structure according to any one of claims 1 to 5, characterized in that: T1 is 0.06~0.2mm, and T2 is 0.08~0.25mm.

8. The tab structure according to any one of claims 1 to 5, characterized in that: D1 is 1~10mm, D2 is 1~10mm; D2 / D1 is 1~3.

9. A battery comprising a pole core and a pole ear structure electrically connected to the pole core, characterized in that: The tab structure adopts the tab structure as described in any one of claims 1 to 8.

10. A battery according to claim 9, characterized in that: The battery is a lithium-ion battery.

Images