Core pack and battery

Abstract

The utility model provides a core package and a battery, the core package comprises a pole piece and a pole lug, the pole lug comprises a pole lug body connected with the pole piece, the pole lug body is provided with a first area and a second area which are connected, the pole lug further comprises an insulating layer covering at least one side surface of the first area, the surface of the second area is exposed, the thickness of the pole lug body is e, the thickness f of the insulating layer is less than or equal to e / 2. According to the core package, the surface of the first area of the tab body is covered with the insulating layer, so that the mechanical strength and toughness of the tab can be enhanced, the turnover probability of the tab can be reduced in the preparation process of the core package, and the production yield of the core package is improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to a chip pack and a battery. Background Technology

[0002] In the development of lithium-ion batteries, the winding process has a longer history compared to the stacking process. The winding process not only boasts advantages such as mature technology, low cost, and high yield, but also requires less equipment space and is highly efficient, typically achieving a production efficiency of over 12 ppm, meaning it can process more than 12 cells per minute. To reduce the production cost of lithium-ion batteries, using thinner metal foils (such as 5μm thick copper foil) as tabs has become an industry trend. However, thinning the metal foil leads to reduced strength and toughness, resulting in an increased tab folding rate and becoming a bottleneck for the adoption of wound lithium-ion batteries. Utility Model Content

[0003] Embodiments of this application provide a core pack and a battery that can improve the technical problem of the tabs being easily folded.

[0004] In a first aspect, embodiments of this application provide a core package including an electrode sheet and an electrode tab. The electrode tab includes an electrode tab body connected to the electrode sheet. The electrode tab body has a first region and a second region connected together. The electrode tab also includes an insulating layer covering at least one side surface of the first region. The surface of the second region is exposed. The thickness of the electrode tab body is e, and the thickness of the insulating layer is f≤e / 2.

[0005] In one embodiment, the second region has a solder area, and the number of tabs is n. The solder areas of the n tabs are stacked and welded together. Along a first direction, the length of the second region is c, and the length of the solder area is h. Along a second direction, the width of the second region is d, and the width of the solder area is g. The first direction is from the fixed end of the electrode body to the free end of the electrode body, the second direction intersects the first direction, and n is a natural number greater than or equal to 2.

[0006] In one embodiment, the length of the tab body along the first direction is b, and the width of the tab body along the second direction is a, wherein c / b < 1 and d / a < 1.

[0007] In one embodiment, c / b < 0.5, d / a < 0.5.

[0008] In one embodiment, the first region is connected to the electrode, the second region is located at the end of the first region away from the electrode, and the three sides of the second region are surrounded by the first region.

[0009] In one embodiment, the solder area is located at the edge of the second region and is spaced apart from the first region.

[0010] In one embodiment, n tabs are sequentially aligned and disposed on the ends of the electrode sheet in the thickness direction of the core package; the lengths of the n tabs increase sequentially.

[0011] In one embodiment, the core package is a wound core.

[0012] In one embodiment, the insulating layer is a polymer layer.

[0013] In one embodiment, the tab body is a metal foil with a thickness of less than or equal to 5 μm.

[0014] In one embodiment, the insulating layer covers at least the opposite surfaces of the first region.

[0015] In one embodiment, the electrode includes a current collector, the electrode body is integrally formed with the current collector, and the thickness of the current collector is equal to the thickness of the electrode body.

[0016] Secondly, embodiments of this application provide a battery including the aforementioned core pack and housing, wherein the core pack is housed within the housing.

[0017] The beneficial effects of the embodiments of this application are as follows:

[0018] In the core package provided in this application embodiment, by covering the surface of the first region of the electrode body with an insulating layer, the mechanical strength and toughness of the electrode can be enhanced. This reduces the probability of electrode folding during the core package manufacturing process, thereby improving the production yield of the core package. Furthermore, since the surface of the second region of the electrode body remains exposed, it can be ensured that the electrode connected to the electrode can achieve electrical connection with the external circuit. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the main structure of the core package provided in an embodiment of this application;

[0021] Figure 2 This is a schematic diagram of the front view of the tab structure in the core package provided in an embodiment of this application;

[0022] Figure 3 yes Figure 2 Schematic diagram of the cross-sectional structure along line AA;

[0023] Figure 4 This is a cross-sectional structural schematic diagram of the electrode sheet in the core package provided in an embodiment of this application;

[0024] Figure 5 This is a cross-sectional structural diagram of the battery provided in an embodiment of this application.

[0025] Figure label:

[0026] 1. Core pack; 11. Electrode; 111. Current collector; 112. Active material layer; 12. Tab; 120. Tab body; 121. First region; 122. Second region; 123. Insulating layer; 124. Soldering area; 10. Battery; 2. Casing. Detailed Implementation

[0027] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] Furthermore, it should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of this application. In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in its actual use or operation, specifically the directions shown in the accompanying drawings; while "inner" and "outer" refer to the outline of the device.

[0029] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0030] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0031] The terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0032] In the description of the embodiments of this application, the words "example" or "for example" are used to indicate exemplification, illustration, or description. Any embodiment or design described as "example" or "for example" in the embodiments of this application is not to be construed as being more preferred or having more advantages than another embodiment or design. The use of the words "example" or "for example" is intended to present relative concepts in a clear manner.

[0033] To facilitate understanding of the present application, the spline curves and arrows used in the reference numerals in the accompanying drawings are explained below: spline curves without arrows indicate solid parts, that is, parts with solid structures; spline curves with arrows indicate virtual parts, that is, parts without solid structures.

[0034] Firstly, please see Figures 1 to 4 Embodiments of this application provide a core pack 1 for use in a battery 10. The battery 10 includes, but is not limited to, at least one of a liquid battery and a solid-state battery.

[0035] Please see Figures 1 to 3 The core package 1 includes an electrode 11 and a tab 12, with the tab 12 connected to the electrode 11. The tab 12 includes a tab body 120, which is connected to the electrode 11. The tab body 120 has a first region 121 and a second region 122, which are connected. The tab 12 also includes an insulating layer 123, which covers at least one side surface of the first region 121, while the surface of the second region 122 is exposed. The thickness of the tab body 120 is e, and the thickness f of the insulating layer 123 is ≤ e / 2.

[0036] The tab body 120 is connected to the electrode 11, allowing charge to transfer between the tab 12 and the electrode 11. For example, the tab 12 can transfer charge to the electrode 11, or receive charge from the electrode 11. Here, the electrode 11 can be a positive electrode, in which case the tab 12 is a positive tab; or the electrode 11 can be a negative electrode, in which case the tab 12 is a negative tab. It should be noted that the tab body 120 is a conductor.

[0037] The electrode body 120 is divided into at least two regions, namely a first region 121 and a second region 122, which are connected, meaning that charge transfer can also occur between the first region 121 and the second region 122. At least one surface of the first region 121 is covered with an insulating layer 123. For example, the insulating layer 123 may be covered on one surface of the first region 121, or it may be covered on both opposite surfaces of the first region 121.

[0038] The second region 122 has an exposed surface, meaning the insulating layer 123 does not extend to any surface of the second region 122. This allows the second region 122 to be connected to an external circuit, ensuring circuit continuity. For example, the second region 122 can be connected to the terminals of the battery 10, either directly or indirectly. Here, the external circuit refers to the circuit other than the tabs 12 and the electrode plates 11.

[0039] Since the tab 12 also includes an insulating layer 123 covering the surface of the first region 121, the insulating layer 123 can support the first region 121 to a certain extent, thereby enhancing the mechanical strength and toughness of the tab 12. This can reduce the probability of the tab 12 folding during the preparation of the core package 1 and improve the production yield of the core package 1.

[0040] Furthermore, the thickness f of the insulating layer 123 is less than or equal to half the thickness e of the tab body 120, i.e., f ≤ e / 2. By controlling the thickness of the insulating layer 123, it is prevented that the insulating layer 123 is too thick, which would affect the manufacturing of the core package 1 and reduce the energy density of the core package 1. Here, the thickness f of the insulating layer 123 refers to the insulating layer 123 covering one side surface of the first region 121. It can be understood that when the insulating layer 123 is covered on only one side surface of the first region 121, the tab 12 only includes a single layer of insulating layer 123 with a thickness of f; when the insulating layers 123 are covered on both opposite sides of the first region 121, the tab 12 includes two layers of insulating layer 123, each with a thickness of f, i.e., the sum of the thicknesses of the two insulating layers 123 in the tab 12 is 2f.

[0041] Therefore, in the core package 1 provided in this application embodiment, by covering the surface of the first region 121 of the tab body 120 with an insulating layer 123, the overall mechanical strength and toughness of the tab 12 can be enhanced. This reduces the probability of the tab 12 folding during the core package 1 manufacturing process, thereby improving the production yield of the core package 1. In addition, since the surface of the second region 122 of the tab body 120 remains exposed, it can be ensured that the electrode 11 connected to the tab 12 can achieve electrical connection with the external circuit.

[0042] In some embodiments, the insulating layer 123 covers at least the opposite sides of the first region 121. This makes it difficult for the first region 121 to conduct electricity when it indirectly contacts other charged bodies through the insulating layer 123. For example, if the tab 12 consists only of the tab body 120 and the tab body 120 is relatively thin, the tab 12 is prone to inserting into the core package 1, causing a short circuit. Covering both opposite sides of the first region 121 with the insulating layer 123 reduces the risk of a short circuit in the core package 1. Here, "insertion of the tab 12" refers to the tab 12 being inserted into the core package 1.

[0043] As an example, if electrode 11 is a positive electrode, then the tab 12 connected to it is a positive tab. The core package 1 also includes a negative electrode with the opposite polarity to electrode 11. When tab 12 is inserted and tab 12 contacts the negative electrode, the presence of insulating layer 123 can reduce the probability of the first region 121 being electrically connected to the negative electrode, thereby reducing the risk of short circuit in core package 1.

[0044] Similarly, if electrode 11 is a negative electrode, then the tab 12 connected to it is a negative tab. The core package 1 also includes a positive electrode with the opposite polarity to electrode 11. When tab 12 is inserted and contacts the positive electrode, the presence of insulating layer 123 can reduce the probability of the first region 121 being electrically connected to the positive electrode, thereby reducing the risk of short circuit in core package 1.

[0045] In other words, by covering the opposite sides of the first region 121 with an insulating layer 123, the probability of the tab 12 bending and causing internal insertion can be reduced during the use of the core package 1, thereby reducing the risk of short circuit of the core package 1; in addition, even if the tab 12 is inserted, the presence of the insulating layer 123 can further reduce the risk of short circuit of the core package 1.

[0046] In some embodiments, see Figure 2 The second region 122 has a soldering area 124, and the number of tabs 12 is n. The n tabs 12 are stacked and soldered together through the soldering area 124. Along the first direction, the length of the second region 122 is c, and the length of the soldering area 124 is h. Along the second direction, the width of the second region 122 is d, and the width of the soldering area 124 is g. The first direction is from the fixed end of the tab body 120 to the free end of the tab body 120, the second direction intersects the first direction, and n is a natural number greater than or equal to 2.

[0047] The solder area 124 is formed primarily through welding processes, such as ultrasonic welding and laser welding, to weld together n tabs 12, thereby ensuring the effective transmission of current and the reliability of the connection within the core package 1. n is a natural number greater than or equal to 2; the larger n is, the more tabs 12 are stacked and welded together. For example, n can be 2, 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, or 100.

[0048] In the fabrication of the core package 1, the integrity of the solder area 124 has a significant impact on the welding quality. Due to the arrangement of the insulating layer 123, the thickness of different parts of the tab 12 varies, and by setting the length of the solder area 124 to... The width of solder area 124 is set to This ensures the integrity of the solder area 124. It can be seen that the length of the solder area 124 is less than the length of the second region 122, and the width of the solder area 124 is less than the width d of the second region 122, that is, the solder area 124 is a part of the second region 122.

[0049] Please see Figure 2 The first direction is the direction from the fixed end of the tab body 120 to the free end of the tab body 120, i.e., the Y-axis direction shown in the figure. Here, the fixed end of the tab body 120 refers to the end of the tab body 120 that is connected and fixed to the electrode plate 11, and the free end of the tab body 120 refers to the end of the tab body 120 away from the electrode plate 11. The dimensions of the tab body 120, the second region 122, and the solder area 124 in the first direction are respectively called the length b of the tab body 120, the length c of the second region 122, and the length h of the solder area 124. The second direction is the direction that intersects with the first direction, for example, the second direction is perpendicular to the first direction, i.e., the X-axis direction in the figure. The dimensions of the tab body 120, the second region 122, and the solder area 124 in the second direction are respectively called the width a of the tab body 120, the width d of the second region 122, and the width g of the solder area 124.

[0050] In some embodiments, see Figure 2Along the first direction, the length of the tab body 120 is b, and along the second direction, the width of the tab body 120 is a, where c / b < 1 and d / a < 1. That is, the second region 122 is a part of the tab body 120, and at least two sides of the second region 122 are surrounded by the first region 121 and the insulating layer 123. This reduces the probability of a short circuit caused by accidental contact between the sides of the second region 122 and other live structures. Simultaneously, the first region 121 and the insulating layer 123 also provide support and protection for the second region 122. For example, c / b is 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, or 0.9; d / a is 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, or 0.9.

[0051] In some embodiments, c / b < 0.5 and d / a < 0.5. That is, the ratio of the surface area of ​​the second region 122 to the total surface area of ​​the tab body 120 is < 0.5. When the tab body 120 only includes the first region 121 and the second region 122, the surface area of ​​the second region 122 is smaller than the surface area of ​​the first region 121. The smaller the values ​​of c / b and d / a, the larger the surface area of ​​the first region 121 and the smaller the surface area of ​​the second region 122. By increasing the surface area of ​​the first region 121, since the surface of the first region 121 is covered by the insulating layer 123, the probability of the tab 12 accidentally coming into contact with other live structures and causing a short circuit can be reduced, thereby improving the safety of the core package 1.

[0052] In some embodiments, see Figure 1 and Figure 2 The first region 121 is connected to the electrode 11, and the second region 122 is located at the end of the first region 121 away from the electrode 11. The three sides of the second region 122 are surrounded by the first region 121.

[0053] It is understood that the electrode 11, the first region 121, and the second region 122 are connected sequentially. The first region 121 is located between the electrode 11 and the second region 122, while the second region 122 is away from the electrode 11. When n tabs 12 are stacked and soldered together through the solder area 124, the first region 121 provides a buffer, preventing the second region 122 from being pulled and breaking. In addition, the first region 121 surrounds the three sides of the second region 122, and similarly, the insulating layer 123 surrounds the three sides of the second region 122. This reduces the probability of the sides of the second region 122 accidentally coming into contact with other live structures and causing a short circuit. At the same time, the first region 121 and the insulating layer 123 also provide support and protection for the second region 122.

[0054] For example, see Figure 2A U-shaped opening is formed on the free end of the first region 121, and the second region 122 is located within the U-shaped opening.

[0055] In some embodiments, the solder area 124 is located at the edge of the second region 122 and spaced apart from the first region 121. Positioning the solder area 124 at the edge of the second region 122 facilitates soldering operations. Since the surface of the first region 121 is covered with an insulating layer 123, the thickness of the solder area 124 is typically less than the sum of the thicknesses of the first region 121 and the insulating layer 123. Positioning the solder area 124 spaced apart from the first region 121 helps ensure the integrity of the solder area 124.

[0056] For example, see Figure 2 The second region 122 is rectangular, and the solder area 124 in the second region 122 is also rectangular. The area in the second region 122 other than the solder area 124 is called the transition area, which is U-shaped.

[0057] In some embodiments, see Figure 1 In the thickness direction of the core package 1, n tabs 12 are sequentially aligned and arranged on the ends of the electrode sheet 11; the lengths of the n tabs 12 are sequentially increased.

[0058] Here, the n tabs 12 are aligned sequentially, meaning that the orthographic projections of the n tabs 12 coincide along the thickness direction of the core package 1. It can be understood that parallel relationships between different tabs 12 are not required.

[0059] For example, see Figure 1 The thickness direction of the core package 1 is the Z direction, and the core package 1 contains 8 tabs 12, that is, n=8. Along the Z direction, the tabs 12 are, in order, the first tab, the second tab, the third tab, the fourth tab, the fifth tab, the sixth tab, the seventh tab, and the eighth tab. The length of the first tab is b1, the length of the second tab is b2, the length of the third tab is b3, the length of the fourth tab is b4, the length of the fifth tab is b5, the length of the sixth tab is b6, the length of the seventh tab is b7, and the length of the eighth tab is b8. The lengths of the tabs satisfy the following relationship: b1 < b2 < b3 < b4 < b5 < b6 < b7 < b8.

[0060] By setting the n tabs 12 to have progressively increasing lengths, it is easier to stack and solder the second region 122, located at the end of the first region 121 away from the electrode 11, together through the soldering area 124.

[0061] In some embodiments, the tab body 120 is a metal foil. Metal foil not only has good conductivity but also good formability, thus ensuring the performance of the tab body 120 while reducing its manufacturing difficulty. For example, if tab 12 is the positive tab, the metal foil is aluminum foil; if tab 12 is the negative tab, the metal foil is copper foil.

[0062] In some implementations, the thickness of the metal foil is less than or equal to 5 μm. Reducing the thickness of the metal foil can lower the cost of the tab 12. For example, the thickness of the metal foil may be 3 μm, 4 μm, or 5 μm.

[0063] In some embodiments, the insulating layer 123 is a polymer layer. Polymers have good insulation and withstand voltage properties, and the polymer layer effectively prevents short circuits caused by the insertion of the tab 12. As an example, the polymer includes at least one of polyethylene (PE), polypropylene (PP), polytetrafluoroethylene (PTFE), and polyvinylidene fluoride (PVDF).

[0064] Core pack 1, also known as electrode assembly, is the core component that constitutes the battery cell (also known as a single battery cell).

[0065] The core package 1 mainly includes a positive electrode, a negative electrode, and a separator. The positive electrode, negative electrode, and separator are stacked together. The separator is located between the positive and negative electrode to separate them and prevent direct contact between the positive and negative electrode, which could lead to a short circuit. The core package can contain one or more separators, one or more positive electrode, and one or more negative electrode. The electrode 11 can be either a positive or a negative electrode.

[0066] In some embodiments, the core package 1 is a wound core. A wound core means that the core package 1 is a wound structure, with the positive electrode sheet, separator, and negative electrode sheet stacked and wound together. As an example, the layers are stacked in the manner of one separator layer, one positive electrode sheet, one separator layer, one negative electrode sheet, and one separator layer, and then wound together using a winding process to obtain the wound core. When the core package 1 is a wound core, typically one electrode sheet 11 can be connected to multiple tabs 12.

[0067] Since the core is prepared by a winding process, the tabs 12 connected to the electrode sheet 11 are more prone to folding during the winding process. Optimizing the structure of the tabs 12 can reduce the folding rate of the tabs 12, thereby improving the production yield of the core.

[0068] Of course, in some embodiments, the core package 1 can also be a stacked structure. When the core package 1 is a stacked structure, the core package 1 is stacked layer by layer in the order of positive electrode, separator, negative electrode, and separator. As an example, the core package 1 has one separator, and multiple positive and negative electrodes. The separator is continuously bent in a "Z" shape to be stacked with the positive and negative electrodes layer by layer. As an example, the separator in the core package 1 is a cut individual film, and there are multiple separators, multiple positive and negative electrodes. The core package 1 can be obtained by stacking one layer of separator, one layer of positive electrode, one layer of separator, and one layer of negative electrode. When the core package 1 is a stacked structure, usually one electrode 11 can be connected to one tab 12.

[0069] In some embodiments, see Figure 4 The electrode 11 includes a current collector 111, and a tab body 120 integrally formed with the current collector 111, with the thickness of the current collector 111 being equal to the thickness of the tab body 120. This allows for the direct reservation of a portion of the structure (e.g., metal foil) used to fabricate the current collector 111 during electrode 11 fabrication as the tab body 120, facilitating the manufacturing of the tab body 120 and ensuring the connection strength between the tab body 120 and the current collector 111. Furthermore, this design reduces production costs.

[0070] For some implementation methods, please refer to Figure 4 The electrode 11 also includes an active material layer 112, which is disposed on the current collector 111. The active material layer 112 can be disposed on one side of the current collector 111, or it can be disposed on both sides of the current collector 111. The active material layer 112 contains electrode active material.

[0071] When electrode 11 is a positive electrode, the active material layer 112 is a positive active material layer, and the electrode active material contained in the active material layer 112 is a positive active material. As an example, the positive active material includes at least one of lithium iron phosphate, lithium manganese iron phosphate, and lithium nickel cobalt manganese oxide.

[0072] When electrode 11 is a negative electrode, the active material layer 112 is a negative electrode active material layer, and the electrode active material contained in the active material layer 112 is a negative electrode active material. As an example, the negative electrode active material includes at least one of graphite, silicon oxide, and silicon carbon.

[0073] In some embodiments, electrode 11 includes a positive electrode and a negative electrode, and electrode tab 12 includes a positive electrode tab and a negative electrode tab, wherein the positive electrode is connected to the positive electrode tab and the negative electrode is connected to the negative electrode tab.

[0074] Secondly, please see Figure 5 An embodiment of this application provides a battery 10, including the aforementioned core pack 1 and housing 2, wherein the core pack 1 is loaded inside the housing 2.

[0075] As an example, battery 10 includes a lithium-ion battery.

[0076] In some embodiments, the battery 10 includes, but is not limited to, at least one of a liquid battery and a solid battery.

[0077] In some embodiments, the battery 10 is at least one of a battery cell, a battery module, and a battery pack.

[0078] In some embodiments, the battery 10 is a single battery cell. The casing 2 includes a body and a cover. The body has a receiving cavity with one end open, the core package 1 is disposed in the receiving cavity, and the cover is disposed on the body and closes the receiving cavity. A terminal post is also provided on the cover, and the tab 12 on the core package 1 is connected to the terminal post.

[0079] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A core wrap, characterized by, The tab includes a tab body connected with the pole piece, the tab body has a first region and a second region connected, the tab further includes an insulating layer covering at least one side surface of the first region, and a surface of the second region is exposed, a thickness of the tab body is e, and a thickness of the insulating layer is f ≤ e / 2.

2. The core wrap of claim 1, wherein, The second region has a welding area, the number of the tab is n, the welding area of the n tabs are laminated together along a first direction, the length of the second region is c, the length of the welding area is h, along a second direction, the width of the second region is d, the width of the welding area is g, wherein, The first direction is from the fixed end of the tab body to the free end of the tab body, the second direction intersects the first direction, and n is a natural number greater than or equal to 2.

3. The core wrap of claim 2, wherein, In the first direction, a length of the tab body is b, and in the second direction, a width of the tab body is a, wherein c / b < 1 and d / a < 1.

4. The core wrap of claim 3, wherein, c / b < 0.5 and d / a < 0.

5.

5. The core wrap of any one of claims 2 to 4, wherein, The first region is connected with the pole piece, the second region is located at an end of the first region away from the pole piece, and three sides of the second region are surrounded by the first region.

6. The core wrap of claim 5, wherein, The welding mark region is located at an edge of the second region and is spaced apart from the first region.

7. The core wrap of claim 6, wherein, In a thickness direction of the core package, n tab bodies are sequentially arranged on an end of the pole piece, and lengths of the n tab bodies sequentially increase.

8. The core wrap of any one of claims 1 to 4, wherein, The insulating layer is a polymer layer, and / or the core package is a roll core, and / or the tab body is a metal foil with a thickness less than or equal to 5 μm, and / or the insulating layer covers at least two opposite side surfaces of the first region.

9. The core wrap of any one of claims 1 to 4, wherein, The pole piece includes a current collector, the tab body is integrally formed with the current collector, and a thickness of the current collector is equal to a thickness of the tab body.

10. A battery, characterized by The core package includes the core package and a shell, and the core package is loaded in the shell. The tab includes a tab body connected with the pole piece, the tab body has a first region and a second region connected, the tab further includes an insulating layer covering at least one side surface of the first region, and a surface of the second region is exposed, a thickness of the tab body is e, and a thickness of the insulating layer is f ≤ e / 2. In the first direction, a length of the tab body is b, and in the second direction, a width of the tab body is a, wherein c / b < 1 and d / a < 1. c / b < 0.5 and d / a < 0.

5. The first region is connected with the pole piece, the second region is located at an end of the first region away from the pole piece, and three sides of the second region are surrounded by the first region. The welding mark region is located at an edge of the second region and is spaced apart from the first region. In a thickness direction of the core package, n tab bodies are sequentially arranged on an end of the pole piece, and lengths of the n tab bodies sequentially increase. The insulating layer is a polymer layer, and / or the core package is a roll core, and / or the tab body is a metal foil with a thickness less than or equal to 5 μm, and / or the insulating layer covers at least two opposite side surfaces of the first region. The pole piece includes a current collector, the tab body is integrally formed with the current collector, and a thickness of the current collector is equal to a thickness of the tab body. The core package includes the core package and a shell, and the core package is loaded in the shell.

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