Roll core, lithium ion battery and electric equipment

Abstract

The utility model relates to a roll core, a lithium ion battery and electric equipment. The roll core comprises a positive plate, a negative plate and a diaphragm located between the positive plate and the negative plate, the positive plate is connected with a positive tab, and the negative plate is connected with a negative tab; wherein first heat blocking layers are arranged on the surfaces of the two sides of the negative pole lug, and second heat blocking layers are arranged in empty foil areas, opposite to the two sides of the negative pole lug, of the wound negative pole piece. According to the scheme provided by the invention, the risk of positive and negative electrode short-circuit contact can be reduced, heat transfer at the negative electrode lug can be blocked, and the risk of thermal runaway of the battery can be further reduced.

Description

Technical Field

[0001] The present application relates to new energy, and in particular to winding cores, lithium-ion batteries and electrical equipment. Background Art

[0002] During use, lithium batteries will inevitably encounter external force damage such as collision, extrusion, puncture, or safety risk problems such as overcharging and over-discharging. When these occur, the internal temperature of the battery will rise sharply, causing thermal runaway of the battery, and eventually leading to combustion or explosion.

[0003] In related technologies, internal short circuit of lithium-ion batteries is one of the main factors causing thermal runaway. When a short circuit occurs, the current increases instantly, and a large amount of heat is generated inside the battery. However, due to the limitations of the soft-pack battery cell structure, the heat cannot be directly discharged to the outside, and the battery temperature rises rapidly, causing a violent reaction between the active material and the electrolyte, leading to thermal runaway. Utility Model Content

[0004] In order to solve or partially solve the problems existing in the related art, the present application provides a winding core, a lithium-ion battery and an electrical equipment, which can not only reduce the risk of short-circuit contact between the positive and negative poles, but also block the heat transfer in the negative electrode tab, thereby reducing the risk of thermal runaway of the battery.

[0005] In a first aspect, the present application provides a winding core, comprising:

[0006] A positive electrode sheet, a negative electrode sheet, and a separator located between the positive electrode sheet and the negative electrode sheet, wherein the positive electrode sheet is connected to the positive electrode tab, and the negative electrode sheet is connected to the negative electrode tab;

[0007] Wherein, a first heat barrier layer is provided on both side surfaces of the negative electrode tab, and a second heat barrier layer is provided on the empty foil area opposite to both sides of the negative electrode tab after the negative electrode sheet is wound.

[0008] In one implementation, the first heat barrier layer and the second heat barrier layer are adhesive tapes.

[0009] In one implementation, the adhesive tape is high temperature resistant adhesive tape.

[0010] In one implementation, the thickness of the first heat barrier layer and / or the second heat barrier layer is ≥16 um.

[0011] In one implementation, the negative electrode tab includes a tab substrate, and a surface of the tab substrate is provided with an electroplated nickel layer.

[0012] In one implementation, the diaphragm includes a composite base film composed of a plurality of different or identical materials, and the composite base film has the properties of a high melting point and a low closed-cell temperature.

[0013] In one implementation, the composite base film is made of at least one of PP, PE, and PP materials.

[0014] A second aspect of the present application provides a lithium-ion battery, comprising:

[0015] A battery body, the battery body comprising a winding core, the positive electrode sheet of the winding core extending therefrom having a positive electrode tab, and the negative electrode sheet extending therefrom having a negative electrode tab;

[0016] The core is encapsulated by an aluminum-plastic film, which is a thermally synthesized film whose encapsulation strength decreases at a preset temperature.

[0017] In one implementation, the positive electrode tab and / or the negative electrode tab are encapsulated with a low-melting-point composite tab glue and the aluminum-plastic film.

[0018] A third aspect of the present application provides an electrical device, including:

[0019] The device body is equipped with the lithium-ion battery described in the second aspect above.

[0020] The technical solution provided by this application may have the following beneficial effects:

[0021] The winding core provided in the present application has a first heat barrier layer provided on both side surfaces of the negative electrode tab, and a second heat barrier layer is provided on the empty foil area opposite to the two sides of the negative electrode tab after the negative electrode sheet is wound. The first heat barrier layer and the second heat barrier layer can not only reduce the risk of short-circuit contact between the positive and negative electrodes, but also can block the heat transfer in the negative electrode tab, thereby reducing the risk of thermal runaway of the battery.

[0022] Furthermore, the aluminum-plastic film of the lithium battery of the present application is a thermally synthesized film whose packaging strength decreases at a preset temperature. When a short circuit occurs, heat can be discharged in time to prevent the lithium battery from burning or exploding, thereby improving the safety of battery use.

[0023] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The above and other objects, features and advantages of the present application will become more apparent through a more detailed description of exemplary embodiments of the present application in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the present application.

[0025] Figure 1 Schematic diagram of the structure of the winding core shown in the embodiment of the present application;

[0026] Figure 2is a partially enlarged schematic diagram of a winding core shown in an embodiment of the present application;

[0027] Figure 3 Schematic diagram of the structure of the lithium-ion battery shown in the embodiment of the present application.

[0028] Figure numerals: 100, winding core; 101, positive electrode sheet; 102, negative electrode sheet; 1021, end; 103, diaphragm; 111, positive electrode tab; 112, negative electrode tab; 122, first heat barrier tape; 132, second heat barrier layer; 200, battery body; 201, aluminum-plastic film. DETAILED DESCRIPTION

[0029] The preferred embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the present application are shown in the accompanying drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. Instead, these embodiments are provided to make the present application more thorough and complete, and to fully convey the scope of the present application to those skilled in the art.

[0030] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. As used in this application and the appended claims, the singular forms "a," "an," "the," and "the" are intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0031] It should be understood that although the terms "first", "second", "third", etc. may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of this application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0032] In the description of this application, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0033] Unless otherwise expressly specified or limited, terms such as "mounted," "connected," "connect," and "fixed" should be interpreted broadly. For example, they may refer to fixed or detachable connections, or integration; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0034] In the related art, internal short circuit of lithium-ion batteries is one of the main factors causing thermal runaway. When a short circuit occurs, the current increases instantly, and a large amount of heat is generated inside the battery. However, the soft-pack battery cell structure is limited and the heat cannot be directly discharged to the outside. As a result, the battery temperature rises rapidly, causing a violent reaction between the active material and the electrolyte, leading to thermal runaway. To address the above problems, the embodiments of the present application provide a coil and a lithium-ion battery that can block the heat transfer of the negative electrode ear, thereby reducing the risk of thermal runaway.

[0035] The technical solutions of the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0036] Figure 1 Schematic diagram of the structure of the winding core shown in the embodiment of the present application; Figure 2 It is a partially enlarged schematic diagram of the winding core shown in the embodiment of the present application.

[0037] See also Figure 1 and Figure 2 The present application provides a winding core 100, comprising a positive electrode sheet 101, a negative electrode sheet 102, and a separator 103 located between the positive electrode sheet 101 and the negative electrode sheet 102 ( Figure 1 and Figure 2 The positive electrode sheet 101 is connected to the positive electrode tab 111, and the negative electrode sheet 102 is connected to the negative electrode tab 112; wherein, the negative electrode sheet 102 is affixed with a first heat-blocking adhesive tape 122 on both sides of the surface where the negative electrode tab 112 is connected, and the second heat-blocking adhesive tape is affixed to the empty foil area on both sides of the connection between the negative electrode sheet 102 and the negative electrode tab 112.

[0038] The winding core provided in the present application has a first heat barrier layer provided on both side surfaces of the negative electrode tab, and a second heat barrier layer is provided on the empty foil area opposite to the two sides of the negative electrode tab after the negative electrode sheet is wound. The first heat barrier layer and the second heat barrier layer can not only reduce the risk of short-circuit contact between the positive and negative electrodes, but also can block the heat transfer in the negative electrode tab, thereby reducing the risk of thermal runaway of the battery.

[0039] In some embodiments, the negative electrode tab 112 is connected to a region of the negative electrode sheet 102 in the winding core 100 near an end 1021 of the negative electrode sheet 102 , and the first heat-blocking tape 122 is attached to both sides of the negative electrode sheet 102 near the end 1021 .

[0040] In some embodiments, the first heat barrier layer 122 and the second heat barrier layer 132 are adhesive tapes with heat barrier properties. Alternatively, in other embodiments, the first heat barrier layer 122 and the second heat barrier layer 132 are coated colloids with heat barrier properties to block heat transfer from the negative electrode tab.

[0041] Furthermore, the first heat barrier layer 122 and the second heat barrier layer 132 are made of high-temperature resistant adhesive tape. High-temperature resistant adhesive tape maintains its adhesion at high temperatures, resists peeling and deformation, and improves battery performance stability. The high-temperature resistant temperature range is 150-500°C, but is not limited thereto and can also be above 500°C. In some embodiments, the high-temperature resistant adhesive tape can be polyimide (PI) tape, silicone tape, or PET tape.

[0042] In some embodiments, the thickness of the first thermal barrier layer 122 and / or the second thermal barrier layer 132 is greater than or equal to 16 μm.

[0043] In some embodiments, the negative electrode tab 112 includes a tab substrate connected to the negative electrode sheet, with a nickel-plated layer provided on the surface of the tab substrate. The tab substrate can be a metal with good electrical conductivity, such as copper. In some embodiments, the negative electrode tab substrate can also be made of nickel. Using nickel or copper-plated nickel for the negative electrode tab can provide a good electron transmission path, improve electrical conductivity, enhance heat dissipation, and ensure efficient operation of the battery.

[0044] In some embodiments, the separator 103 comprises a composite base film composed of multiple different or identical materials, characterized by a high melting point and a low pore-closing temperature. The low pore-closing temperature means that when the battery experiences an abnormal condition (such as overcharging or a short circuit) that causes the internal temperature to rise, the separator 103 can automatically close its pores at a relatively low temperature, preventing further electrolyte flow and thus effectively preventing thermal runaway and explosion. The high melting point ensures that the separator maintains its structural integrity and stability even in high-temperature environments, preventing melting and causing internal short circuits in the battery. The separator 103 of this application exhibits low pore-closing and high rupture temperatures, effectively increasing the difference between the pore-closing and rupture temperatures, thereby enhancing battery safety. When a large amount of heat is generated within the battery and the temperature approaches the melting point of the polymer material (110-130°C), the separator's pores close, creating a thermal shutdown. This blocks further ion transmission, creating a short circuit and protecting the battery. This also improves the ductility and tensile strength of the composite separator 103, thereby enhancing its puncture resistance.

[0045] In some embodiments, the diaphragm 103 is made of at least one of PP, PE, and PP materials, but is not limited thereto and may also be other materials having similar properties to the above materials.

[0046] Figure 3 Schematic diagram of the structure of the lithium-ion battery shown in the embodiment of the present application.

[0047] See also Figure 1 and Figure 3 The present application provides a lithium-ion battery, which includes a battery body 200, wherein the battery body includes a winding core 100 as described in any one of the above embodiments, wherein the positive electrode sheet 101 of the winding core 100 is led out with a positive electrode tab 111, and the negative electrode sheet 102 is led out with a negative electrode tab 112; wherein the winding core 100 is encapsulated by an aluminum-plastic film 201, and the aluminum-plastic film 201 is a synthetic film whose encapsulation strength decreases at a preset temperature.

[0048] In some embodiments, the aluminum-plastic film 201 is made by a thermal process, or the aluminum-plastic film 201 is made by compounding aluminum foil and CPP with polyethylene (MPP). The polyethylene (MPP) is modified to bond the aluminum foil and CPP. Thermal synthesis is performed at a certain temperature. The inner layer CPP has a low melting point and is not affected at normal temperatures. When used at ultra-high temperatures, the packaging strength will be reduced, and flatulence can be easily discharged when it occurs, preventing explosion, thereby improving the safety of battery use.

[0049] In this embodiment, the positive electrode tab 111 and / or the negative electrode tab 112 are encapsulated with a low-melting-point composite tab glue and an aluminum-plastic film 201, wherein the failure temperature of the inner side of the low-melting-point tab glue is ≤130°C. In this way, encapsulation with the aluminum-plastic film 201 can be achieved at a lower temperature, which helps to reduce energy consumption during the packaging process and reduce the potential impact of high temperature on battery performance.

[0050] In related technologies, when a lithium battery experiences a safety risk short circuit, the current instantly increases, generating a large amount of heat inside the battery. However, due to the structural limitations of the soft-pack battery cell, the heat cannot be directly discharged to the outside, causing the battery temperature to rise rapidly, triggering a violent reaction between the active material and the electrolyte, leading to thermal runaway. The lithium-ion battery of this application can not only reduce the probability of short-circuit contact between the positive and negative electrodes inside the lithium-ion battery, but also block the transfer of heat to the negative electrode tab. In addition, the aluminum-plastic film is a synthetic film whose packaging strength decreases at a preset temperature. Therefore, when a short circuit occurs, the heat can be discharged in time, preventing the occurrence of combustion or explosion, thereby improving the safety of battery use.

[0051] The present application also provides an electrical device, wherein the device body is equipped with a lithium-ion battery as described in the above embodiment. The electrical device of the present application can be an electronic device such as a mobile power bank, a smartphone, a tablet computer, or a laptop computer. Because the electrical device of the present application includes the lithium-ion battery of the above embodiment, thermal runaway of the lithium-ion battery can be prevented, thereby improving the safety and service life of the electrical device.

[0052] The embodiments of the present application have been described above. The above description is illustrative and not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the embodiments, their practical applications, or improvements to the technology in the market, or to enable other persons skilled in the art to understand the embodiments disclosed herein.

Claims

1. A winding core, characterized in that: include: A positive electrode sheet, a negative electrode sheet, and a separator located between the positive electrode sheet and the negative electrode sheet, wherein the positive electrode sheet is connected to the positive electrode tab, and the negative electrode sheet is connected to the negative electrode tab; Wherein, a first heat barrier layer is provided on both side surfaces of the negative electrode tab, and a second heat barrier layer is provided on the empty foil area opposite to both sides of the negative electrode tab after the negative electrode sheet is wound.

2. The winding core according to claim 1, characterized in that: The first heat barrier layer and the second heat barrier layer are adhesive tapes.

3. The winding core according to claim 2, wherein: The adhesive tape is a high temperature resistant adhesive tape.

4. The winding core according to claim 1, wherein: The thickness of the first heat barrier layer and / or the second heat barrier layer is ≥16 μm.

5. The winding core according to claim 1, wherein: The negative electrode tab comprises a tab substrate, and a surface of the tab substrate is provided with an electroplated nickel layer.

6. The winding core according to claim 1, characterized in that: The diaphragm comprises a composite base film formed by compounding a plurality of different or same materials, and the composite base film has the properties of high melting point and low closed-cell temperature.

7. The winding core according to claim 6, characterized in that: The composite base film is made of at least one of PP, PE and PP materials.

8. A lithium ion battery, characterized in that: include: A battery body, the battery body comprising the winding core according to any one of claims 1 to 5, the positive electrode sheet of the winding core being led out with a positive electrode tab, and the negative electrode sheet being led out with a negative electrode tab; The core is encapsulated by an aluminum-plastic film, which is a thermally synthesized film whose encapsulation strength decreases at a preset temperature.

9. The lithium-ion battery according to claim 8, wherein: The positive electrode tab and / or the negative electrode tab are packaged with a low-melting-point composite tab glue and the aluminum-plastic film.

10. An electrical device, characterized in that: include: A device body, wherein the lithium-ion battery according to claim 8 or 9 is installed in the device body.

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