Composite current collector, pole piece, battery cell, battery and electric equipment

Abstract

The utility model provides a composite current collector, pole piece, battery cell, battery and electric equipment, it includes: support layer, support layer including body and a plurality of support pillar, the support pillar is inclined in the body, and the included angle formed between the extension direction of support pillar and the thickness direction of body is the acute angle of adjustment; and the two conductive layers are connected to the two sides of the supporting layer respectively. The supporting columns are arranged in the body, so that the supporting layer has the function of compression resilience, when the supporting layer is subjected to the stress action of rolling winding or the interior of the winding core, the inclination angle of the supporting columns can be changed, the stress is released, and then the purpose of preventing the winding core from wrinkling and deforming is achieved; therefore, the cycle capacity of the battery cell is improved to the greatest extent, and the service life and effect are prolonged. Compared with the conventional battery structure at the present stage, the battery structure has the advantages of simple structure, low processing and manufacturing cost, wide application range, capability of releasing the stress of the roll core in real time, reusability and the like.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, and specifically refers to a composite current collector, a pole piece, a battery core, a battery and electrical equipment. Background Art

[0002] In existing lithium-ion battery technology, the current collector is an important component of the battery, which is mainly responsible for current conduction and mechanical support. Traditionally, the current collector is mainly made of copper foil or aluminum foil, which are widely used due to their good electrical conductivity and mechanical strength. However, as lithium-ion batteries develop towards high energy density, the current collector material also needs to have higher performance to meet higher performance requirements.

[0003] In order to increase the energy density of batteries, researchers began to explore the use of composite current collectors, which are usually composed of metals and other materials (such as polymers). This composite structure aims to improve the elasticity and flexibility of the current collector through the introduction of a polymer layer, thereby providing better adaptability during the manufacture and operation of the battery. During the battery manufacturing process, the composite current collector is rolled and wound to form a core pole piece, which causes the polymer layer to be stretched and deformed.

[0004] Although composite current collectors have advantages in improving battery flexibility and adaptability, the rebound effect of the polymer layer will cause stress inside the core during long-term use of the battery. This stress will not only cause mutual squeezing between the current collectors, but may also cause the current collectors to wrinkle and deform during the cyclic charge and discharge process. The wrinkle deformation will destroy the structural integrity of the current collector, affect its current conduction efficiency, and may further cause internal short circuits or other failures in the battery, thereby shortening the battery life and reducing its safety. Summary of the invention

[0005] Therefore, the technical problem to be solved by the utility model is to overcome the problem that the composite current collector in the prior art is easy to wrinkle and deform, and to provide a composite current collector, an electrode, a battery cell and a battery.

[0006] In order to solve the above technical problems, the utility model provides a composite current collector, which includes: a support layer, the support layer includes a main body and a plurality of support columns, the plurality of support columns are obliquely arranged inside the main body, and the angle formed between the extension direction of the support columns and the thickness direction of the main body is an adjusted acute angle; two conductive layers, the two conductive layers are respectively connected to the two sides of the thickness direction of the support layer.

[0007] In an embodiment of the present invention, the angle of the adjusted acute angle is 45-80°.

[0008] In an embodiment of the present invention, two ends of the support column are respectively connected to two sides of the body in the thickness direction, and the support column can rotate and rebound inside the body.

[0009] In one embodiment of the present invention, the change value of the thickness of the composite current collector is d, where 0 μm <d≤5μm。

[0010] In one embodiment of the utility model, when the support column is squeezed by external force, the support column rotates and the angle of the adjusted acute angle gradually increases; when the external force is removed, the support column rebounds and the angle of the adjusted acute angle gradually decreases.

[0011] In one embodiment of the present invention, the body includes a first surface and a second surface spaced apart along a thickness direction thereof, and the first surface and the second surface are respectively connected to two ends of the support column.

[0012] In an embodiment of the present invention, a plurality of the support columns are arranged parallel to each other.

[0013] The utility model provides a pole piece, which comprises a plurality of the above-mentioned composite current collectors and two active material layers, wherein the two active material layers are respectively arranged on two opposite sides of the composite current collector.

[0014] The utility model provides a battery core, which comprises the above-mentioned pole piece.

[0015] The utility model provides a battery, which comprises the above-mentioned battery core.

[0016] The utility model provides an electric device, which comprises the battery mentioned above.

[0017] The above technical solution of the utility model has the following advantages compared with the prior art:

[0018] The composite current collector, pole piece, battery cell, battery and electrical equipment described in the utility model have a plurality of support columns arranged inside the main body so that the support layer has the function of compression and rebound. When it is subjected to the stress of roller winding or the internal stress of the winding core, the inclination angle of the support column will change, thereby releasing the stress, thereby achieving the purpose of avoiding wrinkling and deformation of the winding core, thereby maximizing the cycle capacity of the battery cell and extending its service life and effect. Compared with the conventional battery structure at this stage, this application has the advantages of simple structure, low processing and manufacturing cost, wide range of use, real-time release of winding core stress and reusability, and has considerable use prospects in this industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to make the content of the utility model more clearly understood, the utility model is further described in detail below based on specific embodiments of the utility model in combination with the accompanying drawings.

[0020] Figure 1 It is a schematic diagram of the layer structure of the composite current collector in the preferred embodiment of the utility model;

[0021] Figure 2 yes Figure 1 Schematic diagram of the composite current collector during roller pressing process;

[0022] Figure 3 It is a schematic diagram of the relative relationship between the composite current collector body and the support column before being squeezed by external force;

[0023] Figure 4 It is a schematic diagram of the relative relationship between the body and the support column when the composite current collector is squeezed by an external force;

[0024] Figure 5 It is a schematic diagram of the relative relationship between the composite current collector body and the support column after being squeezed by external force;

[0025] Explanation of the reference numerals in the specification: 100, supporting layer; 110, main body; 111, first surface; 112, second surface; 120, supporting column; 200, conductive layer; 300, rolling main roller. DETAILED DESCRIPTION

[0026] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0027] Embodiment 1

[0028] See also Figures 1 to 3 As shown, this embodiment provides a composite current collector, which includes: a support layer 100, the support layer 100 includes a main body 110 and a plurality of support columns 120, the plurality of support columns 120 are obliquely arranged inside the main body 110, and the angle formed between the extension direction of the support columns 120 and the thickness direction of the main body 110 is an adjusted acute angle; two conductive layers 200, the two conductive layers 200 are respectively connected to both sides of the support layer 100 in the thickness direction.

[0029] The composite current collector described in this embodiment enables the support layer 100 to have the function of compression and rebound through multiple support columns 120 arranged inside the body 110. When it is subjected to the stress of roller winding or the internal stress of the core, the inclination angle of the support column 120 will change, thereby releasing the stress, thereby achieving the purpose of avoiding the wrinkling and deformation of the core, thereby maximizing the cycle capacity of the battery cell and extending its service life and effect. Compared with the conventional battery structure at this stage, this application has the advantages of simple structure, low processing and manufacturing cost, wide range of use, real-time release of core stress and reusability, and has considerable prospects for use in this industry.

[0030] See also Figure 1 As shown, the two conductive layers 200 in this embodiment are both composite conductive layers 200, preferably metal powder composite conductive layers 200, whose base material contains one or more of copper powder, aluminum powder, and nickel powder. The conductive layer 200 can give the current collector good conductivity and reduce the migration resistance of electrons on the surface of the current collector, thereby improving the charging and discharging efficiency of the battery to achieve the purpose of efficient energy storage of the battery. In practical applications, the material and structural design of the composite conductive layer 200 will be optimized according to the specific needs and application environment of the battery, and the utility model does not impose specific restrictions on its specific material and internal structure design. Furthermore, the two conductive layers 200 in this embodiment are connected to the support layer 100 by coating and curing, thereby minimizing the processing cost while improving the preparation efficiency.

[0031] Furthermore, the main body 110 and the support column 120 in the support layer 100 are preferably made of elastic materials. In this embodiment, the base materials of the two are the same and preferably polyethylene, so that while the support column 120 is deflected for mechanical buffering, it also has an elastic buffering effect, thereby maximizing the absorption of the roller pressure stress by the support layer 100, and achieving the best effect of preventing the core from wrinkling and deforming. In other embodiments, the main body 110 and the support column 120 can be respectively set to one or more elastic polymers such as polyvinylidene fluoride, polytetrafluoroethylene, polypropylene, polyacrylonitrile, polystyrene, polyacrylamide, polyimide, polyurethane, styrene-butadiene rubber, and aramid, and the utility model does not make specific restrictions.

[0032] See also Figure 2 and Figure 3 As shown, the body 110 in this embodiment includes a first surface 111 and a second surface 112 spaced apart along a thickness direction thereof, and the first surface 111 and the second surface 112 are respectively connected to two ends of the support column 120 .

[0033] Furthermore, in this embodiment, the preparation method of the support layer 100 mainly includes:

[0034] S1. Mix the polymer and the additive to form a stable and uniform suspension slurry. In other embodiments, the polymer can also be made fluid by melting or other processing methods, thereby reducing the use of additives.

[0035] S2, inject the suspension slurry into the first mold to prepare the first support layer semi-finished product, wherein the first mold is used to prepare the first surface 111 and the first support member, and the length of the first support member is half of the total length of the support column 120, so the shape of the first mold matches the first surface 111 and the first support member; similarly, inject the suspension slurry into the second mold to prepare the second support layer semi-finished product, wherein the second mold is used to prepare the second surface 112 and the second support member, and the length of the second support member is half of the total length of the support column 120, so the shape of the second mold matches the second surface 112 and the second support member. Specifically, after the suspension slurry is injected into the corresponding mold, it can be spread by auxiliary elements such as a scraper or a die head to ensure that the suspension slurry can completely fill the corresponding mold.

[0036] S3, connecting the first support layer semi-finished product with the second support layer semi-finished product, so that the plurality of first support members are connected and fixed one by one with the plurality of second support members, thereby forming a complete support layer 100, and obtaining the target composite current collector. Furthermore, in this process, the connection between the first support layer semi-finished product and the second support layer semi-finished product can be achieved by means of adhesive or hot melt.

[0037] After completing the above processing process, the multiple support columns 120 in this embodiment are arranged parallel to each other, and the adjustment acute angle is 30° at this time. The two ends of any support column 120 are respectively connected to the two sides in the thickness direction of the main body 110, and the support column 120 can rotate and rebound inside the main body 110.

[0038] During the processing of the winding core, the current collector needs to be rolled by a rolling device. Rolling can increase the contact area of ​​the current collector surface, reduce the migration resistance of electrons inside the current collector, thereby improving the conductivity of the entire electrode structure, and also increase the mechanical strength of the current collector and its ability to resist deformation and damage. Figure 2 The composite current collector shown is a reference. In this embodiment, a single rolling process needs to be achieved by rotating two rolling main rollers 300 spaced apart along the height direction of the support layer 100 in the same direction and at the same speed. The two rolling main rollers 300 in this embodiment rotate synchronously in the clockwise and counterclockwise directions respectively, and the spacing distance between the two rolling main rollers 300 is less than the thickness of the support layer 100, thereby ensuring that they can roll the support layer 100. Based on this, the support layer 100 in this embodiment gradually moves from left to right under the driving action of the two rolling main rollers 300.

[0039] Further, see Figure 2 and Figure 3 As shown, during the above roller pressing process, the thickness of the support layer 100 and the state of the support columns 120 change twice:

[0040] First, when the support layer 100 moves between the two main roller presses 300, the first surface 111 and the second surface 112 are simultaneously subjected to extrusion forces from opposite directions. At this time, the total thickness of the support layer 100 gradually decreases, and the support columns 120 inside it will also rotate around the midpoint or end point in its extending direction under the above extrusion forces. Specifically, the support columns 120 in this embodiment will rotate clockwise around their midpoints in the compressed state, thereby causing the angle of the adjustment acute angle to gradually increase from 30° until the thickness of the support layer 100 is in the minimum state, and the angle of the adjustment acute angle reaches 80°. Correspondingly, during the actual change process, the support layer 100 changes from Figure 3 the state of Figure 4 to Figure 3 the state shown by α1 as shown in Figure 4 and gradually changes to α2 as shown in

[0041] Next, when the support layer 100 continues to move, the extrusion forces on the first surface 111 and the second surface 112 from opposite directions decrease simultaneously, and the force change is uniform. At this time, the total thickness of the support layer 100 gradually increases, and the support columns 120 inside it will also rotate around the center point in its extending direction under the above pressure release forces. Specifically, the support columns 110 in this embodiment will rotate counterclockwise around their midpoints in the rebounding state, thereby causing the support columns 120 to rebound at this time. During the above process of this embodiment, the angle of the adjustment acute angle gradually decreases from 80° until when the external extrusion force is completely removed, the angle of the adjustment acute angle rebounds to 45°. Correspondingly, during the actual change process, the support layer 100 changes from Figure 4 the state of Figure 5 to Figure 4 the state shown by α2 as shown in Figure 5 and gradually changes to α3 as shown in

[0042] Among them, the change value of the thickness of the composite current collector is d, where 0μm < d ≤ 5μm. During the rotation of the support columns 120, the thickness of the support layer 100 also changes accordingly, that is, the overall thickness of the composite current collector changes. The greater the change value of the adjustment acute angle, the greater the change value of the thickness of the support layer 100, and its change value is between 0 - 5μm.

[0043] Furthermore, the process of gradually thinning the support layer 100 also partly depends on the elastic compression properties of its own material. Its own elasticity and the compression rebound process of the support column 120 can further increase the degree of deformation in the above-mentioned rolling process, thereby making the anti-wrinkle ability of the composite current collector described in this application much higher than that of ordinary current collectors.

[0044] In this embodiment, elastic fatigue loss will inevitably occur after the support layer 100 undergoes rolling rebound motion. Therefore, in actual use, it is difficult to adjust the angle of the acute angle and the thickness of the body 110 to return to the original value. Figure 3 The state shown is not the state shown, but the state of the subsequent repeated extrusion and rebound. Figure 4 and Figure 5 The adjustment is continuously adaptively adjusted in the state, so that the adjustment acute angle α1 in this embodiment is greater than the adjustment acute angle α3 and greater than the adjustment acute angle α2. Figure 3 Thickness of the middle body 110> Figure 5 Thickness of the middle body 110> Figure 4 The thickness of the main body 110, specifically, the composite current collector described in this embodiment will spontaneously form an adjustment space after being squeezed by an external force, and the support column 120 in this adjustment space will spontaneously change between α2 and α3 depending on whether it is subjected to an external squeezing force, and the thickness of the main body 110 will also change accordingly. Based on this, during the subsequent winding and use of the current collector, the support layer 100 in this embodiment can be continuously adaptively adjusted between 45 and 80° through its own rotation and rebound, and at the same time, the main body 110 with a changing thickness can be used to achieve the effect of improving its internal stress in real time during the operation of the battery cell. In other embodiments, the angle setting of adjusting the acute angle can be designed according to actual use requirements, and the utility model does not impose specific restrictions on this.

[0045] Based on this, the composite current collector described in this embodiment enables the support layer 100 to have the function of compression and rebound through the multiple support columns 120 arranged inside the body 110. When it is subjected to the stress of roller winding or the internal stress of the core, the inclination angle of the support column 120 will change, thereby releasing the stress, thereby achieving the purpose of avoiding wrinkling and deformation of the core, thereby maximizing the cycle capacity of the battery cell and extending its service life and effect. Compared with the conventional battery structure at this stage, this application has the advantages of simple structure, low processing and manufacturing cost, wide range of use, real-time release of core stress and reusability, and has considerable prospects for use in this industry.

[0046] Embodiment 2

[0047] This embodiment provides a pole piece, which includes the composite current collector described in embodiment 1 and two active material layers, and the two active material layers are respectively arranged on opposite sides of the composite current collector. Furthermore, the active material layer includes a positive electrode active material layer and a negative electrode active material layer. When the battery is operating, an electrochemical reaction is carried out on the active material layer. Taking a lithium-ion battery as an example, the positive electrode active material layer is responsible for receiving lithium ions moved from the negative electrode through the electrolyte and reacting chemically with it, thereby releasing electrical energy. The negative electrode active material layer releases lithium ions into the electrolyte, and then transfers them to the positive electrode for reaction. Furthermore, the active material layer is the key to the battery's ability to store and release energy. The positive electrode active material layer usually has a higher energy density and can release more electrical energy in a chemical reaction. The negative electrode active material layer is responsible for receiving lithium ions when the battery is discharged and releasing lithium ions when it is charged. In addition, the active material layer not only participates in the electrochemical reaction, but also provides mechanical support for the electrode and enhances the structural stability of the electrode.

[0048] Based on this, the active material layer in this embodiment is made of pure lithium metal. In other embodiments, the substrate of the positive electrode active material layer can also be selected as lithium cobalt oxide (LCO), lithium manganese oxide (LMO), lithium nickel cobalt manganese oxide (NMC), lithium nickel cobalt manganese and aluminum oxide (NCA), etc. Correspondingly, the negative electrode active material layer can be selected as graphite, silicon-based materials (such as silicon and silicon carbon) or other materials capable of storing lithium ions.

[0049] Embodiment 3

[0050] This embodiment provides a battery cell, which includes the pole piece described in the second embodiment. The battery cell is formed by winding or stacking the positive and negative pole pieces and the separator. When the battery is cycled, the positive and negative pole pieces continue to undergo chemical reactions, resulting in the accumulation of chemical reactants, causing the pole pieces to expand. At this time, the battery cell releases stress by changing the inclination angle of the support column, thereby preventing the battery cell pole pieces from wrinkling and deforming, and improving the cycle capacity.

[0051] Embodiment 4

[0052] This embodiment provides a battery, which includes the battery cell in Embodiment 3. The battery in this embodiment includes but is not limited to lead-acid batteries, nickel-cadmium batteries, nickel-hydrogen batteries, lithium-ion batteries, lithium-iron-phosphate batteries, lithium-manganese-acid batteries, lithium-sulfur batteries, and solid-state batteries.

[0053] Embodiment 5

[0054] This embodiment provides an electric device, including the battery in the fourth embodiment. The electric device in this embodiment can be a car, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, etc. The car can be a fuel car, a gas car or a new energy car. The new energy car can be a pure electric car, a hybrid car or an extended-range car, etc.; the spacecraft includes an airplane, a rocket, a space shuttle and a spacecraft, etc.; the electric toy includes a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy and an electric airplane toy, etc.; the electric tool includes a metal cutting electric tool, a grinding electric tool, an assembly electric tool and an electric tool for railways, such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact drill, a concrete vibrator and an electric planer, etc. The embodiment of the utility model does not impose any special restrictions on the above-mentioned electric devices.

[0055] In summary, the composite current collector, pole piece, battery cell, battery and electrical equipment described in the utility model enable the support layer 100 to have the function of compression and rebound through the multiple support columns 120 arranged inside the main body 110. When it is subjected to the stress of roller winding or the internal stress of the core, the inclination angle of the support column 120 will change, thereby releasing the stress, thereby achieving the purpose of avoiding the wrinkling and deformation of the core, thereby maximizing the cycle capacity of the battery cell and extending its service life and effect. Compared with the conventional battery structure at this stage, this application has the advantages of simple structure, low processing and manufacturing cost, wide range of use, real-time release of core stress and reusability, and has considerable use prospects in this industry.

[0056] Obviously, the above embodiments are merely examples for the purpose of clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the scope of protection of the invention of the utility model.

Claims

1. A composite current collector, characterized in that: include: A support layer (100), the support layer (100) comprising a body (110) and a plurality of support columns (120), the plurality of support columns (120) being obliquely arranged inside the body (110), and an angle formed between an extension direction of the support columns (120) and a thickness direction of the body (110) being an adjusted acute angle; Two conductive layers (200), the two conductive layers (200) are respectively connected to two sides of the support layer (100) in a thickness direction.

2. The composite current collector according to claim 1, characterized in that: The angle of the acute angle adjustment is 45° to 80°.

3. The composite current collector according to claim 1, characterized in that: Two ends of the support column (120) are respectively connected to two sides of the body (110) in the thickness direction, and the support column (120) can rotate and rebound inside the body (110).

4. The composite current collector according to claim 3, characterized in that: The change value of the thickness of the composite current collector is d, where 0 μm <d≤5μm。 5. The composite current collector according to claim 1, characterized in that: The body (110) comprises a first surface (111) and a second surface (112) which are arranged at intervals along a thickness direction thereof; the first surface (111) and the second surface (112) are respectively connected to two ends of the support column (120).

6. The composite current collector according to claim 1, characterized in that: The plurality of support columns (120) are arranged parallel to each other.

7. A pole piece, characterized in that: The composite current collector comprises a plurality of composite current collectors as claimed in any one of claims 1 to 6 and two active material layers, wherein the two active material layers are respectively arranged on two opposite sides of the composite current collector.

8. A battery cell, characterized in that: Including the pole piece as described in claim 7.

9. A battery, characterized in that: The invention comprises the battery cell as claimed in claim 8.

10. An electrical equipment, characterized in that: Comprising the battery as claimed in claim 9.

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