End glue structure, battery cell and battery

Abstract

The invention relates to the technical field of batteries, and particularly discloses an ending glue structure which is characterized by comprising a metal conductive layer and an adhesive layer, the metal conductive layer is provided with a plurality of liquid storage holes to form a porous structure, the adhesive layer is arranged on one side of the metal conductive layer, and the thickness d1 of the metal conductive layer is larger than the thickness d2 of the adhesive layer. The metal conductive layer is provided with a plurality of liquid storage holes to form a porous structure, and the thickness d1 of the metal conductive layer is greater than the thickness d2 of the adhesive layer, so that after the metal conductive layer is connected with the anode strip, the electrolyte retention capacity can be improved, the electrolyte can be stored, the capacity attenuation caused by electrolyte exhaustion in the later period of circulation is effectively inhibited, and the long-circulation performance of the battery is ensured; when winding of the battery cell is ended, the adhesive layer can be directly connected with the outer wall of the naked battery cell in an adhesive manner, so that the problem of cyclic fragment is solved, the space of the battery cell can be saved, and ED is improved. The invention also discloses a battery cell and a battery.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a finishing glue structure, a battery cell and a battery. Background Art

[0002] With the widespread use of steel-shell button batteries in headphones, battery technology is developing towards high ED and long cycle life to improve user experience. Therefore, the development of headphone batteries with high ED and long cycle life will become an important trend in the future. However, the existing steel-shell button batteries are limited by the packaging space and the electrolyte retention capacity is limited. In the later stages of the cycle, the electrolyte is easily dried up, resulting in lithium precipitation on the interface. At the same time, there is a risk of battery breakage. The current solution is to improve the breakage problem by extending the length of the substrate, that is, winding an extra circle of copper foil 10' and a circle of finishing tape 20', such as Figure 1 As shown, this solution wastes battery cell space and sacrifices ED, making it difficult to meet demand. Summary of the Invention

[0003] The technical problem to be solved by the present invention is: how to solve the problems of waste of cell space, sacrifice of ED and short cycle life existing in the prior art.

[0004] In order to solve the above technical problems, the present invention provides a finishing glue structure, including a metal conductive layer and an adhesive layer, the metal conductive layer is provided with a plurality of liquid storage holes to form a porous structure, the adhesive layer is arranged on one side of the metal conductive layer, and the thickness d1 of the metal conductive layer is greater than the thickness d2 of the adhesive layer.

[0005] Further preferably, the metal conductive layer is a porous nickel foam layer.

[0006] Further preferably, the adhesive layer is a polyurethane layer or a polypropylene layer.

[0007] Further preferably, the relationship between the thickness d1 of the metal conductive layer and the thickness d2 of the adhesive layer satisfies: 0.25≤d2 / d1<1.

[0008] Further preferably, the relationship between the thickness d1 of the metal conductive layer and the thickness d2 of the adhesive layer satisfies: d2 / d1=0.25.

[0009] Further preferably, the porosity of the metal conductive layer is 20% to 80%.

[0010] Further preferably, the adhesive layer is loaded on one side of the metal conductive layer by any one of spraying, dipping or hot pressing processes.

[0011] The present invention also provides a battery cell, comprising an anode sheet, a cathode sheet, a diaphragm arranged between the anode sheet and the cathode sheet, and the above-mentioned finishing glue structure, wherein the anode sheet, the cathode sheet and the diaphragm are wound to form a bare battery cell; the metal conductive layer is connected to the finishing end of the anode sheet, and the adhesive layer is bonded to the outer wall of the bare battery cell to form the battery cell.

[0012] Further preferably, the anode sheet comprises a copper current collector and an active material layer, the anode sheet has a hollow foil area and a coating area, the active material layer covers the coating area, and the metal conductive layer is welded to the copper current collector.

[0013] The present invention also provides a battery, comprising a shell and the above-mentioned battery core, wherein the shell covers the battery core.

[0014] Compared with the prior art, the tail glue structure provided by the present invention has the following advantages:

[0015] The finishing glue structure of the present invention is composed of a metal conductive layer and an adhesive layer. The metal conductive layer is provided with a plurality of liquid storage holes to form a porous structure, and the thickness d1 of the metal conductive layer is greater than the thickness d2 of the adhesive layer. After being connected to the anode sheet, it can increase the electrolyte retention amount and realize the storage of the electrolyte, effectively inhibiting the capacity attenuation caused by electrolyte depletion in the late cycle, and ensuring the long cycle performance of the battery; in addition, the adhesive layer is arranged on one side of the metal conductive layer. When the battery cell is wound and finished, the adhesive layer can be directly bonded and connected to the outer wall of the bare battery cell. Compared with the conventional finishing glue method, there is no need to wind an extra circle of copper foil and a circle of finishing tape, thereby improving the cycle breakage problem, and at the same time can save battery cell space and improve ED. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the conventional finishing glue method.

[0017] Figure 2 Schematic diagram of the finishing glue structure of the present invention.

[0018] Figure 3 It is a structural schematic diagram of the battery cell of the present invention.

[0019] Reference numerals: 100, finishing glue structure; 10, metal conductive layer; 20, adhesive layer; 200, copper current collector. DETAILED DESCRIPTION

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0021] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0022] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like used in the present invention to indicate 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 the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the present invention.

[0023] 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 the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0024] Furthermore, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be interpreted broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in the present invention based on the specific circumstances.

[0025] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0026] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0027] like Figure 2 As shown, the present invention provides a finishing glue structure, which includes a metal conductive layer 10 and an adhesive layer 20. The metal conductive layer 10 is provided with a plurality of liquid storage holes to form a porous structure. The adhesive layer 20 is provided on one side of the metal conductive layer 10. The thickness d1 of the metal conductive layer 10 is greater than the thickness d2 of the adhesive layer 20. In this way, the metal conductive layer 10 is provided with a number of liquid storage holes to form a porous structure, and the thickness d1 of the metal conductive layer 10 is greater than the thickness d2 of the adhesive layer 20. After being connected to the anode sheet, it can increase the electrolyte retention capacity and realize the storage of the electrolyte, effectively inhibiting the capacity attenuation caused by electrolyte depletion in the late cycle, and ensuring the long cycle performance of the battery; in addition, the adhesive layer 20 is arranged on one side of the metal conductive layer 10. When the battery cell is wound and finished, the adhesive layer 20 can be directly bonded to the outer wall of the bare battery cell. Compared with the conventional finishing glue method, there is no need to wind an extra circle of copper foil and a circle of finishing tape, thereby improving the cycle breakage problem, and at the same time can save battery cell space and improve ED (energy density).

[0028] In some embodiments, the metal conductive layer 10 is a porous nickel foam layer. On the one hand, the porous structure of the porous nickel foam layer saves space in the bare cell and can effectively store electrolyte, thereby increasing the capacity and ED of the electrode. This inhibits capacity decay caused by electrolyte depletion in the late stages of long cell cycling, ensuring long-term cycle performance and reducing the risk of cycle failure. On the other hand, the porous nickel foam layer can effectively reduce the internal resistance of the electrode, promote rapid electron transport, and improve charge and discharge capabilities.

[0029] In some embodiments, the adhesive layer 20 is a polyurethane adhesive layer or a polypropylene adhesive layer; wherein the polyurethane PU adhesive layer has high elasticity, can adapt to the volume expansion / contraction of the battery cell during the charging and discharging process, reduce stress cracking, and improve the cycle life, and the polyurethane PU adhesive layer has strong adhesion to metal and high sealing reliability, and can be tightly connected to the bare battery cell during the finishing process; and the polypropylene PP adhesive layer can achieve seamless bonding between the metal conductive layer 10 and the bare battery cell, avoiding interface stratification, and the melting point of the polypropylene PP adhesive layer is 160-170°C, and can maintain structural integrity and delay heat spread in high temperature environments (such as the early stage of thermal runaway of the battery cell).

[0030] In some embodiments, the relationship between the thickness d1 of the metal conductive layer 10 and the thickness d2 of the adhesive layer 20 satisfies the following: 0.25 ≤ d2 / d1 < 1. This effectively stores electrolyte, suppresses capacity decay due to electrolyte depletion in the later stages of a long cycle, ensures long-cycle performance, and reduces the risk of cycle failure. If d2 / d1 < 0.25, the adhesive layer 20 is too thin, resulting in poor bonding and an inability to tighten the bare cell. If d2 / d1 ≥ 1, the adhesive layer 20 is too thick, resulting in poor electrolyte retention and an inability to ensure long-cycle performance.

[0031] In some embodiments, the relationship between the thickness d1 of the metal conductive layer 10 and the thickness d2 of the adhesive layer 20 satisfies: d2 / d1=0.25. Thus, the use of the finishing adhesive structure 100 can maximize the cycle performance while increasing the liquid retention capacity.

[0032] In some embodiments, the porosity of the metal conductive layer 10 is 20% to 80%. When the porosity of the metal conductive layer 10 is less than 20%, it restricts electrolyte infiltration and lithium ion diffusion, resulting in reduced kinetic performance and reduced electrolyte retention. When the porosity of the metal conductive layer 10 is greater than 80%, the mechanical strength of the metal conductive layer 10 is reduced. A porosity of 20% to 80% in the metal conductive layer 10 ensures effective electrolyte infiltration, improves the electrolyte retention of the battery cell, and ensures both kinetic performance and mechanical strength.

[0033] In some embodiments, the adhesive layer 20 is loaded onto one side of the metal conductive layer 10 by any of spraying, dipping, or hot pressing processes, thereby forming a composite structure of the finishing adhesive structure 100 that has both porous conductivity and high bonding strength. When the spraying process is used, ultra-thin and uniform coverage of the adhesive layer can be achieved, which is suitable for high-precision requirements; when the dipping process is used, the metal conductive layer 10 can be immersed in the adhesive liquid to achieve full coverage, which is particularly suitable for adhesive loading of porous nickel foam layers. In addition, the dipping process can also form a thicker adhesive layer by adjusting the viscosity of the adhesive liquid or the pulling speed; when the hot pressing process is used, the adhesive layer 20 and the metal conductive layer 10 are physically / chemically bonded by hot pressing, and the hot pressing process can improve the interface connection strength between the two.

[0034] In summary, the finishing glue structure 100 of the present invention is composed of a metal conductive layer 10 and an adhesive layer 20. The metal conductive layer 10 is provided with a plurality of liquid storage holes to form a porous structure, and the thickness d1 of the metal conductive layer 10 is greater than the thickness d2 of the adhesive layer 20. After being connected to the anode sheet, it can increase the electrolyte retention amount and realize the storage of the electrolyte, effectively inhibiting the capacity attenuation caused by electrolyte depletion in the late cycle, and ensuring the long cycle performance of the battery; in addition, the adhesive layer 20 is provided on one side of the metal conductive layer 10. When the battery cell is wound and finished, the adhesive layer 20 can be directly bonded to the outer wall of the bare battery cell. Compared with the conventional finishing glue method, there is no need to wind an extra circle of copper foil and a circle of finishing tape, thereby improving the cycle breakage problem, and at the same time can save battery cell space and improve ED.

[0035] like Figure 3 As shown, the present invention also provides a battery cell comprising an anode sheet, a cathode sheet, a separator disposed between the anode and cathode sheets, and the aforementioned end capping adhesive structure 100. The anode sheet, cathode sheet, and separator are wound to form a bare battery cell; a metal conductive layer 10 is connected to the end of the anode sheet, and an adhesive layer 20 is bonded to the outer wall of the bare battery cell to form the battery cell. The specific structure of the end capping adhesive structure 100 is similar to that of the above-mentioned embodiments. Since this battery cell utilizes all the technical solutions of all the above-mentioned embodiments, it at least has all the beneficial effects brought about by the technical solutions of the above-mentioned embodiments, and will not be further described here.

[0036] It should be noted that the battery cell primarily relies on the movement of metal ions between the anode and cathode sheets to operate. The anode sheet includes a copper current collector 200 and an active material layer. The anode sheet has a bare foil area and a coated area, with the active material layer covering the coated area. The metal conductive layer 10 is connected to the end of the copper current collector 200 by laser welding.

[0037] In some embodiments, the active material layer is a carbon-based layer or a silicon-based layer. The carbon-based layer (e.g., graphite) has a small volume change during charge and discharge, which can maintain the structural integrity of the anode sheet and prevent the active material from pulverizing and falling off. The silicon-based layer has a large specific capacity, which can significantly increase the battery energy density.

[0038] The following experiments further illustrate its effect:

[0039] The finishing glue structure designed by the present invention is applied to the same conventional battery cell model, and a finished battery cell is manufactured through processes such as winding, assembly, and liquid injection, and the following scheme is designed:

[0040] Table 1 Experimental cases

[0041] plan PP / PU adhesive ratio Proportion of porous nickel foam Example 1 10％ 90％ Example 2 20％ 80％ Example 3 30％ 70％ Example 4 40％ 60％ Example 5 50％ 50％ Comparative Example 1 / /

[0042] In the above Table 1, Examples 1-5 are performed by using the finishing glue structure of the present invention. Figure 3 , the difference is that the proportion of PP / PU glue and the proportion of porous nickel foam are different, wherein the proportion of PP / PU glue refers to the ratio of the thickness d2 of the adhesive layer 20 to the total thickness D of the finishing glue structure, and similarly, the proportion of porous nickel foam refers to the ratio of the thickness d1 of the metal conductive layer 10 to the total thickness D of the finishing glue structure; Comparative Example 1 is a conventional structure, that is, an extra circle of copper foil 10' is wound during the finishing, and an extra circle of finishing tape 20' is wound, such as Figure 1 .

[0043] The cells obtained in Examples 1-5 and Comparative Example 1 were tested for bare cell diameter, liquid retention, and room temperature cycling. Cycle data: 3.0C CC to 4.45V, CV 0.05C; 1C DC to 3.0V. Cycles were performed at room temperature (25°C) for 1000 cycles, and the capacity retention was recorded. The test data are as follows:

[0044] Table 2 Experimental data of examples and comparative examples

[0045] plan Bare cell diameter (mm) Liquid retention capacity (g) Cycle retention rate Example 1 10.7 0.24 82.50％ Example 2 10.6 0.22 85.30％ Example 3 10.6 0.20 84.70％ Example 4 10.6 0.19 83.40％ Example 5 10.6 0.16 81.50％ Comparative Example 1 10.9 0.14 80.20％

[0046] According to the experimental results in Table 2 above, the diameter of the bare battery cell is significantly smaller than that of the conventional structure design by using the finishing glue structure 100 of the present invention, and at the same time, the liquid retention capacity can be increased and the cycle performance can be improved. However, if the proportion of the PP / PU glue layer is too small (such as in Example 1), the binding property of the bare battery cell will be worse, the diameter will be larger, and the liquid retention capacity will be too high, resulting in too many side reactions and worsening the cycle performance. On the contrary, if the proportion of the PP / PU glue layer is too large (such as in Example 5), the liquid retention capacity of the battery cell will be reduced and the cycle performance will be poor. When the relationship between the thickness d1 of the metal conductive layer 10 and the thickness d2 of the adhesive layer 20 satisfies: 0.25≤d2 / d1<1, the liquid retention capacity of the battery cell can be increased while ensuring the long cycle performance. According to Table 2, when the relationship between the thickness d1 of the metal conductive layer 10 and the thickness d2 of the adhesive layer 20 satisfies d2 / d1=0.25 (such as in Example 2), the battery cell can improve the liquid retention capacity while improving the cycle performance to the greatest extent, which is the optimal solution.

[0047] The present invention further provides a battery comprising a housing and the aforementioned battery cell, wherein the housing encloses the battery cell. The specific structure of the battery cell is similar to that of the aforementioned embodiments. Since the present battery utilizes all the technical solutions of all the aforementioned embodiments, it at least possesses all the beneficial effects brought about by the technical solutions of the aforementioned embodiments, and therefore will not be further elaborated here.

[0048] A battery refers to a cup, tank, or other container (such as a casing), or a portion of a composite container, that contains an electrolyte solution and metal electrodes to generate an electric current. It is a device that converts chemical energy into electrical energy; batteries have an anode and a cathode. With technological advancements, batteries have come to refer to small devices that can generate electrical energy, such as solar cells. Battery performance parameters primarily include electromotive force, capacity, specific energy, and resistance. Battery Principle: In chemical batteries, the direct conversion of chemical energy into electrical energy occurs through spontaneous chemical reactions such as oxidation and reduction within the battery, which occur at the two electrodes.

[0049] Taking lithium batteries as an example, the cathode current collector can be made of aluminum, and the cathode active material layer can be made of lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The anode current collector can be made of copper, and the anode active material layer can be made of carbon-based materials (such as graphite), silicon-based materials, or alloys. The separator can be made of materials such as polypropylene (PP) or polyethylene (PE). The electrolyte is a material with good ionic conductivity, such as aqueous solutions of acids, bases, or salts, organic or inorganic non-aqueous solutions, molten salts, or solid electrolytes.

[0050] In other embodiments, the battery may be a secondary battery (rechargeable battery), also known as a rechargeable battery or storage battery. This refers to a battery that can be recharged to reactivate the active material after discharge and continue to be used. The reversibility of chemical reactions allows a new battery to be constructed. That is, after a chemical reaction is converted into electrical energy, the electrical energy can be used to repair the chemical system and then be converted back into electrical energy through chemical reactions. Therefore, it is called a secondary battery (rechargeable battery).

[0051] The present invention also proposes an electrical device, which includes the above-mentioned battery. The specific structure of the battery refers to the above-mentioned embodiment. Since this electrical device adopts all the technical solutions of all the above-mentioned embodiments, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0052] Among them, electrical devices may include headphones, vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and electric tools, etc. Vehicles may be fuel vehicles, gas vehicles, or new energy vehicles. New energy vehicles may be pure electric vehicles, hybrid vehicles, or extended-range vehicles, etc. Spacecraft include aircraft, rockets, space shuttles, and spacecraft, etc. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Electric tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This embodiment does not impose any special restrictions on the above-mentioned electrical devices.

[0053] The above description is only a preferred embodiment of the present invention. It should be noted that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be considered as the scope of protection of the present invention. The basic principles, main features and advantages of the present invention are shown and described above. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above preferred embodiments. The examples should be regarded as illustrative and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, it is intended that all changes that fall within the meaning and scope of the equivalent elements of the claims are included in the present invention.

[0054] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in the embodiments can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A finishing glue structure, characterized in that: It comprises a metal conductive layer and an adhesive layer. The metal conductive layer is provided with a plurality of liquid storage holes to form a porous structure. The adhesive layer is provided on one side of the metal conductive layer. The thickness d1 of the metal conductive layer is greater than the thickness d2 of the adhesive layer.

2. A finishing glue structure according to claim 1, characterized in that: The metal conductive layer is a porous nickel foam layer.

3. The finishing glue structure according to claim 1, characterized in that: The adhesive layer is a polyurethane layer or a polypropylene layer.

4. The finishing glue structure according to claim 1, characterized in that: The relationship between the thickness d1 of the metal conductive layer and the thickness d2 of the adhesive layer satisfies: 0.25≤d2 / d1<1.

5. The finishing glue structure according to claim 4, characterized in that: The relationship between the thickness d1 of the metal conductive layer and the thickness d2 of the adhesive layer satisfies: d2 / d1=0.

25.

6. The finishing glue structure according to claim 1, characterized in that: The porosity of the metal conductive layer is 20% to 80%.

7. The finishing glue structure according to claim 1, characterized in that: The adhesive layer is loaded on one side of the metal conductive layer by any one of spraying, dipping or hot pressing processes.

8. A battery cell, characterized in that: It includes an anode sheet, a cathode sheet, a diaphragm arranged between the anode sheet and the cathode sheet, and the finishing glue structure described in any one of claims 1 to 7 above, the anode sheet, the cathode sheet and the diaphragm are wound to form a bare battery core; the metal conductive layer is connected to the finishing end of the anode sheet, and the adhesive layer is bonded to the outer wall of the bare battery core to form the battery core.

9. The battery cell according to claim 8, characterized in that: The anode sheet comprises a copper current collector and an active material layer. The anode sheet has a hollow foil area and a coating area. The active material layer covers the coating area. The metal conductive layer is welded to the copper current collector.

10. A battery, characterized in that: The invention comprises a shell and the battery core according to any one of claims 8 to 9, wherein the shell covers the battery core.

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