CN221008981U - Pole piece and battery - Google Patents
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- CN221008981U CN221008981U CN202322547905.8U CN202322547905U CN221008981U CN 221008981 U CN221008981 U CN 221008981U CN 202322547905 U CN202322547905 U CN 202322547905U CN 221008981 U CN221008981 U CN 221008981U
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- Secondary Cells (AREA)
- Battery Electrode And Active Subsutance (AREA)
- Cell Electrode Carriers And Collectors (AREA)
Abstract
The utility model relates to the technical field of new energy lithium batteries, in particular to a pole piece and a battery. The pole piece includes substrate layer, first adhesive linkage, anodal mass flow body layer, second adhesive linkage and negative pole mass flow body layer, wherein, the substrate layer has first wall and second wall opposite each other along thickness direction, first adhesive linkage is in first wall, first adhesive linkage is including the first corner that is located the corner position of pole piece, anodal mass flow body layer connects in one side that first adhesive linkage deviates from the substrate layer, anodal mass flow body layer is including the second corner that is located the corner position of pole piece, the second adhesive linkage is connected in the second wall, negative pole mass flow body layer connects in one side that the second adhesive linkage deviates from the substrate layer, thickness L 1 of first corner and thickness L 2 of second corner satisfy: l 2/L1 <40 is more than or equal to 20. The battery comprises a pole piece to which the above-described method is applied. The pole piece and the battery provided by the utility model have the advantages that the long-cycle performance, the stability and the safety of the lithium battery are improved.
Description
Technical Field
The utility model relates to the technical field of new energy lithium batteries, in particular to a pole piece and a battery.
Background
Lithium batteries refer to batteries that contain lithium (including metallic lithium, lithium alloys, and lithium ions, lithium polymers) in an electrochemical system. In recent years, with the development of new energy sources, such as a fire, the application range of lithium batteries is becoming wider and wider, and lithium batteries are widely applied to energy storage power supply systems of hydraulic power, firepower, wind power, solar power stations and the like, and various fields of electric tools, electric bicycles, electric motorcycles, electric automobiles, military equipment, aerospace and the like. In the age of rapid development of lithium batteries, the requirements on various working procedures of the lithium batteries in the industry are also increasing.
The separator and the current collector (comprising copper foil and aluminum foil) in the lithium battery are important components of the battery, and directly influence the production process, the electrical performance and the safety performance of the battery. At present, the winding structure of the lithium battery is a composite structure of a positive electrode plate, a diaphragm and a negative electrode plate, and the positive electrode plate, the diaphragm and the negative electrode plate are of a thinner structure and are in a micron level, so that wrinkling is easy to occur at a winding corner in the lamination process, lithium is seriously separated at the winding corner, and the long cycle performance of the battery is greatly influenced, and the stability and the safety of the battery are influenced.
Disclosure of utility model
The utility model mainly aims to provide a pole piece and a battery, and aims to solve the technical problems that a winding structure of a lithium battery is easy to wrinkle and separate out lithium at corners and improve the long-cycle performance, stability and safety of the lithium battery.
To achieve the above object, the present utility model provides a pole piece comprising:
a base material layer having a first wall surface and a second wall surface opposite to each other in a thickness direction;
A first adhesive layer connected to the first wall surface, the first adhesive layer including a first corner portion located at a corner position of the pole piece;
The positive current collector layer is connected to one side of the first bonding layer, which is away from the substrate layer, and comprises a second corner part positioned at the corner position of the pole piece;
a second adhesive layer, the second adhesive layer being connected to the second wall surface;
The negative current collector layer is connected to one side of the second bonding layer, which is away from the substrate layer;
Wherein the thickness L 1 of the first corner portion and the thickness L 2 of the second corner portion satisfy: l 2/L1 <40 is more than or equal to 20.
In some embodiments, the thickness L 1 of the first corner portion and the thickness L 2 of the second corner portion satisfy: l 2/L1 is more than or equal to 25 and less than or equal to 35.
In some embodiments, the thickness L 1 of the first adhesive layer and the thickness L 2 of the positive electrode current collector layer satisfy: l 2/L1 <40 is more than or equal to 20.
In some embodiments, the substrate layer is a polyethylene layer or a polypropylene layer or a polyimide layer or an aramid layer.
In some embodiments, the first adhesion layer is a nano-alumina layer or a silicon oxide layer and the second adhesion layer is a nano-alumina layer or a silicon oxide layer.
In some embodiments, the positive current collector layer is an aluminum metal layer and the negative current collector layer is a copper metal layer.
In some embodiments, the thickness L 3 of the substrate layer satisfies: and the thickness L 1 of the first bonding layer is less than or equal to 3um and less than or equal to 6um, and the thickness L 3 is as follows: l 1 is less than or equal to 80nm and less than or equal to 150nm, and the thickness L 2 of the positive electrode current collector layer meets the following conditions: and the thickness L 4 of the second bonding layer is less than or equal to 3um and less than or equal to 5um, and the thickness L 2 is as follows: l 4 is less than or equal to 80nm and less than or equal to 150nm, and the thickness L 5 of the negative electrode current collector layer meets the following conditions: l 5 is less than or equal to 1um and less than or equal to 2um.
The utility model also provides a battery comprising: at least two layers of pole pieces are provided.
In some embodiments, the battery further comprises:
The isolating film is arranged between two adjacent layers of pole pieces;
The pole piece and the isolating film are wound to form a bare cell.
In some embodiments, the barrier film is a ceramic coated plastic film.
Compared with the prior art, the utility model has the beneficial effects that:
In the technical scheme of the utility model, the pole piece comprises a substrate layer, a first bonding layer, a second bonding layer, a positive pole current collector layer and a negative pole current collector layer. The positive electrode current collector layer and the negative electrode current collector layer are respectively connected to a first wall surface and a second wall surface of the substrate layer, which are opposite to each other, through a first bonding layer and a second bonding layer along the thickness direction of the substrate layer. The first adhesive linkage is provided with first corner portion at the coiling corner of pole piece, and anodal current collector layer is provided with the second corner portion at the coiling corner of pole piece, and thickness L 1 of first corner portion and thickness L 2 of second corner portion satisfy: l 2/L1 <40 is more than or equal to 20. By adopting the structure, the adhesion and bonding capacity of the positive electrode current collector layer and the negative electrode current collector layer is improved through the first adhesive layer and the second adhesive layer, and the deformation, warping and lithium precipitation phenomena at the winding corner of the pole piece caused by different material extensibility are effectively prevented in the pole piece rolling process by changing the thickness proportion relation of the positive electrode current collector layer and the first adhesive layer at the corner of the pole piece, so that the long-cycle performance, the stability and the safety of the lithium battery are greatly improved.
The battery using the pole piece has higher safety performance, longer service life and better long-cycle stability.
Drawings
In order to more clearly illustrate the embodiments of the present utility model or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are only some embodiments of the present utility model, and other drawings may be obtained according to the structures shown in these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic view of a pole piece according to an embodiment of the present utility model;
FIG. 2 is an exploded view of a pole piece according to an embodiment of the present utility model;
Fig. 3 is a schematic view of a battery according to an embodiment of the present utility model.
Reference numerals illustrate:
10-pole pieces;
100-a substrate layer;
110-a first wall; 120-a second wall;
200-a first adhesive layer;
300-positive current collector layer;
400-a second adhesive layer;
500-negative current collector layer;
20-cell;
210-separator film.
The achievement of the objects, functional features and advantages of the present utility model will be further described with reference to the accompanying drawings, in conjunction with the embodiments.
Detailed Description
The following description of the embodiments of the present utility model will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.
It should be noted that, if a directional indication (such as up, down, left, right, front, and rear … …) is included in the embodiment of the present utility model, the directional indication is merely used to explain a relative positional relationship, a movement condition, and the like between the components in a specific posture, and if the specific posture is changed, the directional indication is correspondingly changed.
In addition, if there is a description of "first", "second", etc. in the embodiments of the present utility model, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, if "and/or", "and/or" and/or "are used throughout, the meaning includes three parallel schemes, for example," a and/or B ", including a scheme, or B scheme, or a scheme where a and B meet simultaneously. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent and not within the scope of protection claimed in the present utility model.
With the great development of new energy, the application range of lithium batteries is becoming wider and wider, for example, lithium batteries are widely applied to energy storage power supply systems such as hydraulic power, firepower, wind power and solar power stations, and various fields such as electric tools, electric bicycles, electric motorcycles, electric automobiles, military equipment, aerospace and the like. In the age of rapid development of lithium batteries, the requirements on various working procedures of the lithium batteries in the industry are also increasing.
The separator and the current collector (comprising copper foil and aluminum foil) in the lithium battery are important components of the battery, and directly influence the production process, the electrical performance and the safety performance of the battery. At present, the winding structure of the lithium battery is a composite structure of a positive electrode plate, a diaphragm and a negative electrode plate, and the positive electrode plate, the diaphragm and the negative electrode plate are of a thinner structure and are in a micron level, so that wrinkling is easy to occur at a winding corner in the lamination process, lithium is seriously separated at the winding corner, and the long cycle performance of the battery is greatly influenced, and the stability and the safety of the battery are influenced.
In view of this, in order to solve the problems that the pole piece 10 is easily wrinkled and separated from lithium at the winding corners during the lamination process, and improve the connection stability of the pole piece 10, referring to fig. 1 to 3, an embodiment of the present utility model provides a pole piece 10, which includes a substrate layer 100, a first adhesive layer 200, a second adhesive layer 400, a positive current collector layer 300, and a negative current collector layer 500. The positive electrode current collector layer 300 and the negative electrode current collector layer 500 are respectively connected to two opposite sides of the substrate layer 100 through the first adhesive layer 200 and the second adhesive layer 400, so as to form a composite current collector integrating positive and negative electrodes. With this structure, it is possible to largely reduce the occurrence of "anode-coated cathode" (i.e., the anode area is larger than the cathode area, and all anode areas have anode-facing areas, and the innermost layer of the battery cell has anode-facing areas), and since the battery cells are double-layer coated, i.e., active materials are coated on both sides of the current collector, the anode active materials on the outermost anode layer and the innermost anode inner layer are not utilized, which not only wastes the anode material, results in an increase in battery cost, but also results in a decrease in the mass energy density and volume energy density of the battery cells, or "cathode-coated anode" (i.e., the cathode area is larger than the anode area, and all anode areas have anode-facing areas, and since the cathode is the primary source of lithium ions, in the process of transferring lithium ions from the cathode to the anode, the cathode-coated anode areas at the inner ring corners have insufficient cathode-anode capacity ratio, and the lithium ions of the cathode are not inserted into the anode, and the anode-coated anode has sufficient capacity to fully satisfy the capacity to perform lithium ion intercalation in the anode cycle, resulting in a severe lithium ion intercalation performance degradation of the battery.
Specifically, the base material layer 100 is a polymer insulating base film, and is a film capable of ensuring good electrical insulation. The substrate layer 100 has a very high resistivity (higher than 10Ω·cm) and breakdown field strength, and also has a low dielectric loss to achieve high-frequency insulation. The base material layer 100 has a first wall surface 110 and a second wall surface 120 facing each other in the thickness direction for bonding the positive electrode current collector layer 300 and the negative electrode current collector layer 500, respectively. Further, the substrate layer 100 forms a composite current collector with a certain thickness and integrated positive and negative electrodes through a hydro-electric plating process, wherein the current density of the hydro-electric plating is 7A/dm 2, and the electroplating time T meets the following conditions: t is equal to or less than 5min and equal to or less than 20min, and the value of T can be 5min, 15min, 20min and the like for example.
Further, referring to fig. 1 to 2, in order to improve the adhesive strength of the positive electrode current collector layer 300 and the negative electrode current collector layer 500 to the base material layer 100, the first adhesive layer 200 is connected to the first wall surface 110 of the base material layer 100, the first adhesive layer 200 includes a first corner portion located at the corner position of the pole piece 10, and correspondingly, the second adhesive layer 400 is connected to the second wall surface 120 of the base material layer 100. Because the thicknesses of the positive current collector layer 300 and the negative current collector layer 500 are very thin and are in a micrometer level, by arranging the adhesive layer, the phenomenon that the electrode plate 10 is deformed and warped due to different material extensibility can be effectively avoided when the electrode plate 10 is rolled, so that the risk of lithium precipitation of the electrode plate 10 is reduced, and the stability and safety of the battery 20 are improved.
Further, referring to fig. 1 to 2, a positive electrode current collector layer 300 is connected to a side of the first adhesive layer 200 facing away from the substrate layer 100, i.e., the positive electrode current collector layer 300 is connected to the first wall surface 110 of the substrate layer 100 through the first adhesive layer 200, and the positive electrode current collector layer 300 includes a second corner portion located at a corner position of the pole piece 10, and correspondingly, a negative electrode current collector layer 500 is connected to a side of the second adhesive layer 400 facing away from the substrate layer 100, i.e., the negative electrode current collector layer 500 is connected to the second wall surface 120 of the substrate layer 100 through the second adhesive layer 400. Therefore, a composite pole piece structure with integrated anode and cathode is formed, the situation that the anode is coated with the cathode or the cathode is coated with the anode can be effectively avoided, and the phenomenon of lithium precipitation at corners is effectively improved.
In addition, the composite pole piece structure reduces the usage amount of the positive electrode current collector layer 300 and the negative electrode current collector layer 500 on the whole, and improves the energy density. The thinner current collector layer has smaller size of burrs generated when the strips or the pole pieces 10 are cut, lower risk of internal short circuit and higher pass rate when safety project tests such as needling are carried out.
Further, referring to fig. 3, at the corner position of the pole piece 10, the thickness L 1 of the first corner portion and the thickness L 2 of the second corner portion satisfy: l 2/L1 <40 is more than or equal to 20. Namely, the thickness L 1 of the first adhesive layer 200 at the corner position of the electrode sheet 10 and the thickness L 2 of the positive electrode current collector layer 300 at the corner position of the electrode sheet 10 satisfy: l 2/L1 <40 is more than or equal to 20. Illustratively, L 2/L1 may have a value of 20, 30, 35. By changing the thickness ratio between the positive current collector layer 300 and the first adhesive layer 200 so as to satisfy the above relationship, deformation and warpage of the pole piece 10 caused by different material elongation rates when the pole piece 10 is rolled can be effectively avoided, and further stability and safety of the battery 20 are improved.
It should be noted that, at other positions than the corner positions of the pole piece 10, the thickness L 1 of the first adhesive layer 200 and the thickness L 2 of the positive electrode current collector layer 300 may not satisfy the above relationship.
The improved pole piece 10 provided in this embodiment includes a base material layer 100, a first adhesive layer 200, a second adhesive layer 400, a positive current collector layer 300, and a negative current collector layer 500. The positive electrode current collector layer 300 and the negative electrode current collector layer 500 are connected to the first wall surface 110 and the second wall surface 120 of the base material layer 100, which are opposite to each other, through the first adhesive layer 200 and the second adhesive layer 400, respectively, along the thickness direction of the base material layer 100. The first adhesive layer 200 is provided with a first corner portion at a winding corner of the pole piece 10, the positive electrode current collector layer 300 is provided with a second corner portion at the winding corner of the pole piece 10, and the thickness L 1 of the first corner portion and the thickness L 2 of the second corner portion satisfy: l 2/L1 <40 is more than or equal to 20. By adopting the structure, the adhesion and bonding capacity of the positive electrode current collector layer 300 and the negative electrode current collector layer 500 is improved through the first adhesive layer 200 and the second adhesive layer 400, and the phenomena of deformation warping and lithium precipitation at the winding corner of the pole piece 10 caused by different material elongation in the rolling process of the pole piece 10 are effectively prevented by changing the thickness proportion relation of the positive electrode current collector layer 300 and the first adhesive layer 200 at the corner of the pole piece 10, so that the long-cycle performance, stability and safety of the lithium battery are greatly improved.
In some embodiments, the thickness ratio of the positive current collector layer 300 and the first adhesive layer 200 at the corner of the pole piece 10 may be further accurate, so that the thickness L 1 of the first corner portion and the thickness L 2 of the second corner portion are ensured to satisfy: l 2/L1 and 35, L 2/L1 may be, for example, 25, 30, 35. Based on the same reason as above, by changing the thickness proportion relation between the positive current collector layer 300 and the first adhesive layer 200 at the corner of the pole piece 10, the phenomena of deformation warpage and lithium precipitation at the winding corner of the pole piece 10 caused by different material extensibility are effectively prevented in the rolling process of the pole piece 10, and the long cycle performance, stability and safety of the lithium battery are greatly improved.
In some embodiments, in addition to changing the thickness ratio relationship of the positive current collector layer 300 and the first adhesive layer 200 at the corner of the pole piece 10, the thickness ratio relationship of the positive current collector layer 300 and the first adhesive layer 200 in the whole pole piece 10 may also be changed, so that the thickness L 1 of the first adhesive layer 200 and the thickness L 2 of the positive current collector layer 300 satisfy: 20.ltoreq.L 2/L1 <40, L 2/L1 may have values of 20, 30, 35, for example.
In some embodiments, the substrate layer 100 may be a polyethylene layer or a polypropylene layer or a polyimide layer or an aramid layer, or the substrate layer 100 may be a combination of multiple polyethylene layers, polypropylene layers, polyimide layers, and aramid layers, or the substrate layer 100 may be another polymer insulating substrate layer, and the material composition of the substrate layer 100 does not form a single limitation, and will not be described herein.
By adopting the above materials for the base material layer 100, the production and manufacturing costs are reduced while ensuring good insulation properties, so that the battery 20 has high economic benefits.
In some embodiments, the first adhesive layer 200 may be a nano-alumina layer or a silicon oxide layer, or the first adhesive layer 200 may also be a combination of a nano-alumina layer and a silicon oxide layer, or the first adhesive layer 200 may also be another adhesive layer. Similarly, the second adhesive layer 400 may be a nano alumina layer or a silicon oxide layer, or the second adhesive layer 400 may be a combination of a nano alumina layer and a silicon oxide layer, or the second adhesive layer 400 may be another adhesive layer. The material composition of the first adhesive layer 200 and the second adhesive layer 400 does not constitute a single limitation, and will not be described here again.
Since the thicknesses of the positive electrode current collector layer 300 and the negative electrode current collector layer 500 are relatively thin and are in the micrometer level, the positive electrode current collector layer 300 and the negative electrode current collector layer 500 are easy to deform and warp at corners in the rolling and winding process of the pole piece 10, and the bonding layers are arranged, so that the positive electrode current collector layer 300, the negative electrode current collector layer 500 and the substrate layer 100 are more firmly connected, and the bonding force between the positive electrode current collector layer 300, the negative electrode current collector layer 500 and the substrate layer 100 is enhanced. With such a structure, the probability of deformation warpage of the positive electrode current collector layer 300 and the negative electrode current collector layer 500 at the corners can be reduced during the roll-winding process of the electrode sheet 10, thereby improving the stability and safety of the battery 20.
In some embodiments, the positive current collector layer 300 is an aluminum metal layer and the negative current collector layer 500 is a copper metal layer. Since the aluminum metal layer has a larger elongation than the copper metal layer, referring to the above embodiment, the thicknesses of the current collector layer and the adhesive layer in the pole piece 10 are changed so as to satisfy a certain thickness ratio. By adopting the structure, the deformation and warping of the pole piece 10 caused by the difference of the material extensibility when the pole piece 10 is rolled are effectively avoided.
More preferably, the aluminum metal layer and the copper metal layer are formed on the surface of the bonding layer in a mode of combining magnetron sputtering and water electroplating, and the metal layer prepared by the magnetron sputtering and water electroplating method has strong adhesive force, so that the long-term stability of the battery 20 is facilitated. In addition, the thickness of the metal layer can be controlled by adjusting the technological parameters of water electroplating.
Further, the aluminum metal layer is coated with positive electrode slurry as a positive electrode surface (not shown in the figure) on a side facing away from the first bonding layer 200, the copper metal layer is coated with negative electrode slurry as a negative electrode surface (not shown in the figure) on a side facing away from the second bonding layer 400, and then cold-pressing and slitting are performed to obtain a positive and negative electrode composite pole piece. The positive electrode slurry comprises a positive electrode active material, a conductive agent acetylene black, a conductive carbon nano tube and a binder polyvinylidene fluoride (PVDF), wherein the positive electrode slurry comprises the following components in percentage by weight of 97.8:0.6:0.4:1.2 fully dispersing the cathode slurry in an N-methyl pyrrolidone solvent system, wherein the cathode slurry comprises a cathode active material, a conductive agent and a binder, and the cathode slurry is prepared from the following components in percentage by weight of 97.6:0.8:1.6, mixing.
In some embodiments, the thickness L 3 of the substrate layer 100 satisfies: l 3 um or less and L 3 um or less, and the values of L 3 may be 3um, 4.5um or 6um, for example. The thickness L 1 of the first adhesive layer 200 satisfies: l 1 nm or less and L 1 nm or less, and the values of L 1 may be 80nm, 120nm or 150nm, for example. The thickness L 2 of the positive electrode current collector layer 300 satisfies: l 2 um or less, L 2 may be 3um, 4um, or 5um, for example. The thickness L 4 of the second adhesive layer 400 satisfies: l 4 nm or less and L 4 nm or less, and the values of L 4 may be 80nm, 120nm or 150nm, for example. The thickness L 5 of the anode current collector layer 500 satisfies: l 5 um or less and L 5 may be 1um, 1.5um, or 2um, for example.
It should be noted that, in the embodiment, the thickness is an average thickness, specifically, three points are taken on the layer structure and the thicknesses at the three points are measured respectively, then the average thickness at the three points is obtained, for example, taking the thickness of the substrate layer 100 as an example, three points are taken on one surface of the substrate layer 100, the respective thicknesses at the three points are measured respectively, and then the thicknesses are averaged to obtain the thickness of the substrate layer 100. Similarly, the thickness calculation methods of the first adhesive layer 200, the second adhesive layer 400, the positive electrode current collector layer 300, and the negative electrode current collector layer 500 are vice versa.
Correspondingly, referring to fig. 3, another embodiment of the present utility model further provides a battery 20, where the battery 20 includes at least two layers of the pole piece 10 in any of the above embodiments. Further, an isolating film 210 is arranged between two adjacent layers of pole pieces 10, the pole pieces 10 and the isolating film 210 are wound to form a bare cell, and then electrolyte is encapsulated and injected to manufacture the finished lithium ion battery.
The preparation method of the electrolyte comprises the following steps: firstly, mixing Ethylene Carbonate (EC), propylene Carbonate (PC), diethyl carbonate (DEC) and Propyl Propionate (PP) according to a volume ratio of 1:1:4:4, and then dissolving fully dried lithium salt LiPF6 in the mixed organic solvent according to a ratio of 1mol/L, so as to obtain a prepared electrolyte.
Referring to tables 1 to 2, in order to make the beneficial effects of the battery 20 using the improved pole piece 10 more intuitive, comparative experiments of battery performance were designed for example groups using the pole piece 10 prepared by the improved method described in the present solution and comparative groups using the pole piece 10 prepared by the improved method not described in the present solution, and other preparation methods and structures of the batteries in the example groups and the comparative groups were the same, satisfying the principle of a single variable.
Specifically, referring to table 1, five examples were included in the example group, and four comparative examples were included in the comparative group. In five sets of embodiments, the thickness of the substrate layer 100 in embodiment 1 is 5um, the thickness of the positive electrode current collector layer 300 is 3um, the thickness of the negative electrode current collector layer 500 is 1um, the thicknesses of the first adhesive layer 200 and the second adhesive layer 400 are both 0.08um, and the total thickness of the pole piece 10 is 9um (it should be noted that the total thickness of the pole piece 10 is the same as the following rule of rounding). In example 2, the thickness of the base material layer 100 was 5um, the thickness of the positive electrode current collector layer 300 was 4um, the thickness of the negative electrode current collector layer 500 was 1.5um, the thicknesses of the first adhesive layer 200 and the second adhesive layer 400 were 0.10um, and the total thickness of the electrode sheet 10 was 11um. In example 3, the thickness of the base material layer 100 was 5um, the thickness of the positive electrode current collector layer 300 was 5um, the thickness of the negative electrode current collector layer 500 was 2um, the thicknesses of the first adhesive layer 200 and the second adhesive layer 400 were 0.15um, and the total thickness of the electrode sheet 10 was 12um. In example 4, the thickness of the base material layer 100 was 6um, the thickness of the positive electrode current collector layer 300 was 3um, the thickness of the negative electrode current collector layer 500 was 1um, the thicknesses of the first adhesive layer 200 and the second adhesive layer 400 were 0.08um, and the total thickness of the electrode sheet 10 was 10um. In example 5, the thickness of the base material layer 100 was 3um, the thickness of the positive electrode current collector layer 300 was 3nm, the thickness of the negative electrode current collector layer 500 was 1um, the thicknesses of the first adhesive layer 200 and the second adhesive layer 400 were 0.08um, and the total thickness of the electrode sheet 10 was 7um.
In four comparative examples, the thickness of the base material layer 100 in comparative example 1 was 5um, the thickness of the positive electrode current collector layer 300 was 2um, the thickness of the negative electrode current collector layer 500 was 0.5um, the thicknesses of the first adhesive layer 200 and the second adhesive layer 400 were 0.08um, and the total thickness of the electrode sheet 10 was 8um. In comparative example 2, the thickness of the base material layer 100 was 2um, the thickness of the positive electrode current collector layer 300 was 3um, the thickness of the negative electrode current collector layer 500 was 1um, the thicknesses of the first adhesive layer 200 and the second adhesive layer 400 were 0.08um, and the total thickness of the electrode sheet 10 was 6um. In comparative example 3, the thickness of the base material layer 100 was 5um, the thickness of the positive electrode current collector layer 300 was 3um, the thickness of the negative electrode current collector layer 500 was 1um, the thicknesses of the first adhesive layer 200 and the second adhesive layer 400 were 0.06um, and the total thickness of the electrode sheet 10 was 9um. In comparative example 4, the thickness of the base material layer 100 was 5um, the thickness of the positive electrode current collector layer 300 was 3um, the thickness of the negative electrode current collector layer 500 was 1um, the first and second adhesive layers 200 and 400 were absent, and the total thickness of the electrode sheet 10 was 9um.
| Sequence number | Total thickness of current collector/μm | Polymer insulating base film thickness/. Mu.m | Thickness of aluminum metal layer/μm | Copper metal layer thickness/μm | Adhesive layer thickness/μm |
| Example 1 | 9 | 5 | 3 | 1 | 0.08 |
| Example 2 | 11 | 5 | 4 | 1.5 | 0.10 |
| Example 3 | 12 | 5 | 5 | 2 | 0.15 |
| Example 4 | 10 | 6 | 3 | 1 | 0.08 |
| Example 5 | 7 | 3 | 3 | 1 | 0.08 |
| Comparative example 1 | 8 | 5 | 2 | 0.5 | 0.08 |
| Comparative example 2 | 6 | 2 | 3 | 1 | 0.08 |
| Comparative example 3 | 9 | 5 | 3 | 1 | 0.06 |
| Comparative example 4 | 9 | 5 | 3 | 1 | / |
TABLE 1
The test results showed that, referring to table 2, the K value of the battery in example 1 was 0.32, the internal resistance was 17.6, the post-rolling warp height was 0.47mm, the K value of the battery in example 2 was 0.36, the internal resistance was 16.5, the post-rolling warp height was 0.51mm, the K value of the battery in example 3 was 0.41, the internal resistance was 15.9, the post-rolling warp height was 0.38mm, the K value of the battery in example 4 was 0.29, the internal resistance was 17.5, the post-rolling warp height was 0.50mm, the K value of the battery in example 5 was 0.44, the internal resistance was 17.6, and the post-rolling warp height was 0.49mm.
The K value of the battery in comparative example 1 was 0.27, the internal resistance was 20.8, the warp height after rolling was 0.67mm, the K value of the battery in comparative example 2 was 0.67, the internal resistance was 17.6, the warp height after rolling was 0.54mm, the K value of the battery in comparative example 3 was 0.31, the internal resistance was 17.2, the warp height after rolling was 0.98mm, the K value of the battery in comparative example 4 was 0.37, the internal resistance was 15.6, and the warp height after rolling was 2.52mm.
| Sequence number | K value | Internal resistance of | Warp height/mm after rolling |
| Example 1 | 0.32 | 17.6 | 0.47 |
| Example 2 | 0.36 | 16.5 | 0.51 |
| Example 3 | 0.41 | 15.9 | 0.38 |
| Example 4 | 0.29 | 17.5 | 0.50 |
| Example 5 | 0.44 | 17.6 | 0.49 |
| Comparative example 1 | 0.27 | 20.8 | 0.67 |
| Comparative example 2 | 0.67 | 17.6 | 0.54 |
| Comparative example 3 | 0.31 | 17.2 | 0.98 |
| Comparative example 4 | 0.37 | 15.6 | 2.52 |
TABLE 2
In the lithium battery industry, the K value represents the voltage drop of a battery in unit time, and the unit is generally expressed by mV/d, and is an index for measuring the self-discharge rate of the lithium battery. In this embodiment, the calculation method of the K value is: after the capacity division is finished, measuring the OCV 1, standing for 48 hours at normal temperature, and measuring the OCV 2; k value= (OCV 1-OCV2)/48. The method for testing the warping after the pole piece is rolled comprises the following steps: warpage height pick-up dimensions: 0.1 mm 1.5m, tiling the pole piece on a horizontal tabletop, respectively vertically hanging 100g weights at two ends of the pole piece, and measuring the warping height of the pole piece.
Therefore, in view of the test results, the composite pole piece structure designed by the scheme can be seen to greatly reduce the thickness of the metal current collector, the K value is obviously reduced, the burr size is reduced, the internal short circuit risk is improved, and the safety coefficient is greatly improved. The thickness of the composite current collector metal layer is reduced, which is unfavorable for the rapid transmission of electrons, resulting in an increase in internal resistance. In addition, the composite pole piece structure prepared by the embodiment effectively improves the warping problem after rolling, improves the pole piece quality of the winding process, reduces the cost and increases the efficiency. Meanwhile, the composite pole piece structure can avoid the risk of lithium precipitation caused by unbalanced N/P ratio at the corners, and the stability and safety of the battery are affected.
In some embodiments, the barrier film 210 is a ceramic coated plastic film (PE film). By coating the ceramic material on the plastic film, the electrical insulation performance of the separator 210 can be enhanced, the short circuit caused by contact between the anode and the cathode can be effectively prevented, and the safety performance and the service life of the battery 20 can be improved.
The battery 20 applying the pole piece 10 has higher safety performance, longer service life and better long-cycle stability.
It should be noted that, other contents of the pole piece 10 and the battery 20 disclosed in the present utility model may be referred to the prior art, and will not be described herein.
The foregoing description of the preferred embodiments of the present utility model should not be construed as limiting the scope of the utility model, but rather should be understood to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the utility model as defined by the following description and drawings or any application directly or indirectly to other relevant art(s).
Claims (10)
1. A pole piece, comprising:
a base material layer having a first wall surface and a second wall surface opposite to each other in a thickness direction;
A first adhesive layer connected to the first wall surface, the first adhesive layer including a first corner portion located at a corner position of the pole piece;
The positive current collector layer is connected to one side of the first bonding layer, which is away from the substrate layer, and comprises a second corner part positioned at the corner position of the pole piece;
a second adhesive layer, the second adhesive layer being connected to the second wall surface;
The negative current collector layer is connected to one side of the second bonding layer, which is away from the substrate layer;
Wherein the thickness L 1 of the first corner portion and the thickness L 2 of the second corner portion satisfy: l 2/L1 <40 is more than or equal to 20.
2. The pole piece of claim 1, wherein the thickness L 1 of the first corner portion and the thickness L 2 of the second corner portion satisfy: l 2/L1 is more than or equal to 25 and less than or equal to 35.
3. The pole piece of claim 1, wherein the thickness L 1 of the first adhesive layer and the thickness L 2 of the positive current collector layer satisfy: l 2/L1 <40 is more than or equal to 20.
4. A pole piece according to claim 1, characterized in that the substrate layer is a polyethylene layer or a polypropylene layer or a polyimide layer or an aramid layer.
5. The pole piece of claim 1, wherein the first adhesive layer is a nano-alumina layer or a silicon oxide layer and the second adhesive layer is a nano-alumina layer or a silicon oxide layer.
6. The pole piece of claim 1, wherein the positive current collector layer is an aluminum metal layer and the negative current collector layer is a copper metal layer.
7. A pole piece according to any of claims 1-6, characterized in that the thickness L 3 of the substrate layer satisfies: and the thickness L 1 of the first bonding layer is less than or equal to 3um and less than or equal to 6um, and the thickness L 3 is as follows: l 1 is less than or equal to 80nm and less than or equal to 150nm, and the thickness L 2 of the positive electrode current collector layer meets the following conditions: and the thickness L 4 of the second bonding layer is less than or equal to 3um and less than or equal to 5um, and the thickness L 2 is as follows: l 4 is less than or equal to 80nm and less than or equal to 150nm, and the thickness L 5 of the negative electrode current collector layer meets the following conditions: l 5 is less than or equal to 1um and less than or equal to 2um.
8. A battery, comprising:
At least two layers of pole pieces according to any of claims 1 to 7.
9. The battery of claim 8, further comprising:
The isolating film is arranged between two adjacent layers of pole pieces;
The pole piece and the isolating film are wound to form a bare cell.
10. The battery of claim 9, wherein the separator is a ceramic coated plastic film.
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| CN202322547905.8U CN221008981U (en) | 2023-09-19 | 2023-09-19 | Pole piece and battery |
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| CN202322547905.8U CN221008981U (en) | 2023-09-19 | 2023-09-19 | Pole piece and battery |
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