Electrode plates and manufacturing methods, electrode assemblies, secondary batteries, and power consumption devices

Abstract

This application relates to an electrode plate (10) and a manufacturing method thereof, an electrode assembly, a secondary battery (100) and an electric power consuming device, in which a lithium supplementary space (13) is provided in a current collecting structure (11), the lithium supplementary space (13) is connected to one side of an active layer (12), and the lithium supplementary material in the lithium supplementary space (13) is used to supplement lithium into the battery (100), so as to offset the irreversible lithium loss during cycling, and to improve the total capacity and energy density of the battery (100). The average weight M of the active material corresponding to different distribution regions (14) on the active layer (12) is A are different, the present application controls the sum of the volumes V0 of the lithium refilling spaces (13) corresponding to each distribution region (14) according to the average weight change of the active material in the different distribution regions (14) in a positive correlation, that is, the sum of the volumes of the lithium refilling spaces (13) corresponding to the second distribution region (14b) is relatively large, and the sum of the volumes of the lithium refilling spaces (13) corresponding to the first distribution region (14a) is relatively small. In this way, different lithium is refilled to different distribution regions (14), which is advantageous to realize quantitative and accurate lithium refilling, and improve the energy density and life of the battery (100).

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a current collector plate and a manufacturing method thereof, an electrode assembly, a secondary battery, and a power consumption device.

Background Art

[0002] With the increasing energy demand, the requirements for the endurance and lifespan of lithium-ion batteries are rising. Usually, the initial Coulomb efficiency of a silicon negative electrode is low. To apply it to battery products, it is necessary to replenish lithium to improve the energy density and lifespan.

[0003] The coating process thins the edges of the current collector plate to avoid the problem of thick edges at the edges. In some cases, lithium replenishment methods such as lithium strip rolling may result in too much lithium replenishment in the thinned area, causing lithium precipitation problems, or too little lithium replenishment in the middle wide surface area, resulting in problems where capacity loss and lifespan improvement do not meet expectations.

Summary of the Invention

[0004] Based on this, it is necessary to provide a current collector plate and a manufacturing method thereof, an electrode assembly, a secondary battery, and a power consumption device to achieve quantitative and accurate lithium replenishment and improve the energy density and lifespan of the battery.

[0005] In a first aspect, this application provides a current collector plate, including a current collecting structure and two active layers, which are respectively provided on opposite side surfaces in the thickness direction of the current collecting structure, and a plurality of lithium replenishment spaces are provided for communicating with one side of the active layer in the current collecting structure, and a lithium replenishment agent is accommodated in the lithium replenishment space. On the distribution area on the active layer communicating with the lithium replenishment space, let the average weight of the active material per unit area of the active layer be M A And let the sum of the inner volumes of the lithium replenishment spaces covered by the projection of the distribution area in the thickness direction of the current collecting structure be V0. The distribution area includes at least a first distribution area and a second distribution area. Here, M in the first distribution area Ais M in the second distribution region A is smaller, and the corresponding V0 in the first distribution region is smaller than the corresponding V0 in the second distribution region.

[0006] The above-mentioned electrode plate installs a lithium replenishment space in the current collector structure, communicates the lithium replenishment space with one side of the active layer, uses the lithium replenishment agent in the lithium replenishment space to replenish lithium into the battery, and offsets the irreversible lithium loss in the cycle process, improving the total capacity and energy density of the battery. The average weight M of the corresponding active materials in at least two distribution regions on the active layer A is different. Therefore, in this application, according to the change in the average weight of the active materials in different distribution regions, the sum V0 of the pore volumes of the lithium replenishment spaces corresponding to each distribution region is controlled in positive correlation, that is, the sum of the volumes in the corresponding lithium replenishment space in the second distribution region is large, and the sum of the volumes in the corresponding lithium replenishment space in the first distribution region is small. In this way, different amounts of lithium are replenished for different distribution regions, realizing quantitative and accurate lithium replenishment. On the premise of the same lithium replenishment amount, it is possible to avoid the problem of lithium precipitation due to too much lithium replenishment amount in the first distribution region, or the problem that the lithium replenishment amount in the second distribution region is too small to meet the expectation of capacity loss or life improvement, which is beneficial to improving the energy density and life of the battery.

[0007] In some embodiments, the depth of the lithium replenishment space is d, and the thickness of the active layer corresponding to the position where the lithium replenishment space is located is h. Here, h in the first distribution region is smaller than h in the second distribution region, and the corresponding d in the first distribution region is smaller than the corresponding d in the second distribution region. In this way, not only can a quantitative and accurate lithium replenishment effect be realized, but also the processing process of the lithium replenishment space can be simplified and the manufacturing efficiency of the electrode plate can be improved.

[0008] In some embodiments, the depth d of the lithium replenishment space is

Number

[0009] Here, C A is the initial lithium intercalation capacity of the negative electrode active material in mAh / g, and C C is the initial lithium release capacity of the positive electrode active material in mAh / g, M C is the average weight of the active material per unit area of the positive electrode in g / cm 2 ). P is the ratio of the opening area of all lithium replenishment spaces per unit area of the current collector structure. Thus, by setting the upper limit value of the depth of the lithium replenishment space, excessive lithium is prevented from being replenished, avoiding lithium precipitation during the negative electrode side cycling process, which is beneficial for improving the safety of the battery.

[0010] In some embodiments, the ratio P of the opening area of all lithium replenishment spaces per unit area satisfies the relationship 10% ≤ P ≤ 50%. In this way, it is ensured that there is sufficient space to accommodate the lithium replenisher, the pore area ratio of the lithium replenishment space is reasonably controlled, and the stability of the electron conduction function of the current collector structure is ensured.

[0011] In some embodiments, the depth d of the lithium replenishment space is

Equation

[0012] In some embodiments, the lithium replenishment spaces are spaced apart in at least one active layer, with equal spacing between any two adjacent lithium replenishment spaces. This uniform arrangement of lithium replenishment spaces facilitates uniform diffusion of lithium replenishment, resulting in improved battery performance.

[0013] In some embodiments, the current collection structure includes at least one current collector in the thickness direction of the current collection structure, and a lithium replenishment space is provided through at least one of the current collectors on which the active layer is installed. In this way, not only is electron conduction facilitated, but holes are also made in the current collection structure, and lithium replenishment can be stably deposited in the lithium replenishment space.

[0014] In some embodiments, the current collection structure includes two current collectors, with two active layers provided on two opposing sides of each current collector, and lithium replenishment spaces are provided through both current collectors. The provision of lithium replenishment spaces through each current collector allows both active layers to effectively replenish lithium, further improving the battery's energy density and cycle life.

[0015] In some embodiments, the current collector structure further includes at least one lithium replenishment layer located between two current collectors. By placing at least one lithium replenishment layer between the two current collectors, the amount of lithium replenishment can be increased, and the battery cycle life can be effectively improved.

[0016] In some embodiments, the lithium replenishment space is a lithium replenishment hole that extends into the active layer on one side along the thickness direction of the current collector structure. Designing the lithium replenishment space as a lithium replenishment hole and extending one end of the lithium replenishment hole into the active layer in this way not only simplifies the electrode manufacturing process but is also advantageous for controlling the corresponding lithium replenishment amount in different distribution regions, resulting in more precise lithium replenishment.

[0017] In some embodiments, the first distribution region is extended along the periphery of the second distribution region. This allows the average weight M of the active material near the edge of the electrode plate to be A M is the average weight of the active material near the center of the electrode plate. A Making it smaller and designing it in this way is advantageous in solving the problem of bulging caused by the plate edges being too thick.

[0018] In a second aspect, the present application provides a method for manufacturing an electrode plate, providing two single-sided electrode plates, wherein the single-sided electrode plate includes a current collector and an active layer provided on one side of the current collector, and at least one single-sided electrode plate has lithium replenishment holes extending into the active layer relative to the current collector, and the average weight M of the active material per unit area in at least two distribution regions on the active layer A The sum of the volumes inside the lithium replenishment holes V0 in the first distribution region is given by M A M in the second distribution region A The method includes steps S200 of controlling the distribution so that it is smaller and the corresponding V0 in the first distribution region is smaller than the corresponding V0 in the second distribution region, and here the distribution region includes the first distribution region and the second distribution region; step S300 of depositing lithium replenisher in lithium replenishment holes; and step S400 of bonding the sides of two single-sided electrodes that are not facing the active layer to each other.

[0019] The above method for manufacturing the electrode plate is simple surface By creating the required electrodes by bonding them together, the manufacturing process is significantly simplified. At the same time, it is made easier to create holes in the electrodes, ensuring that the lithium replenisher is stably deposited in the lithium replenishment holes, thereby achieving a quantitative and accurate lithium replenishment effect.

[0020] In some embodiments, step S200 includes step S210 of obtaining the thickness h of the active layer in different distribution regions, step S220 of uniformly opening a plurality of lithium replenishment holes in the current collector, and step S230 of controlling the depth d of the lithium replenishment holes in the projected region on the current collector of each distribution region such that h in the first distribution region is smaller than h in the second distribution region, and the corresponding d in the first distribution region is smaller than the corresponding d in the second distribution region. In this way, by using the thickness of the active layer as a reference, the control of the parameter of the sum of the internal volumes of the lithium replenishment holes is converted to control of the depth of the lithium replenishment holes, which not only enables quantitative and accurate lithium replenishment effect but also simplifies the processing process of lithium replenishment holes and improves the efficiency of electrode plate manufacturing.

[0021] In some embodiments, the depth d of the lithium replenishment hole is

number

[0022] Here, C A This is the initial lithium storage capacity of the negative electrode active material in mAh / g, and C C This is the initial lithium release capacity of the positive electrode active material mAh / g, and M C This is the average weight of the active material per unit area of ​​the positive electrode (g / cm³). 2 Here, P is the ratio of the total area of ​​all lithium replenishment holes per unit area on the current collection structure. By designing in this way, it is advantageous to set an upper limit on the depth of the lithium replenishment holes, thereby avoiding the deposition of lithium in the negative electrode cycle process due to the replenishment of excess lithium, and improving the safety performance of the battery.

[0023] In some embodiments, the depth d of the lithium replenishment hole is

number

[0024] Here, CE CThis is the initial Coulomb efficiency of the positive electrode active material, CE A This is the initial Coulomb efficiency of the negative electrode active material, C A This represents the initial lithium storage capacity of the negative electrode active material in mAh / g. By setting a lower limit for the depth of the lithium replenishment holes in this way, it is possible to easily fill the lithium replenishment holes with lithium replenishment agent, realize the full utilization of the positive electrode active material capacity, and effectively improve the energy density.

[0025] In a third aspect, the application provides an electrode assembly including a positive electrode plate, a negative electrode plate, and a separator provided between the positive electrode plate and the negative electrode plate, wherein the positive electrode plate and / or negative electrode plate are the electrode plates described in any one of the above paragraphs.

[0026] The above electrode assembly employs the above-mentioned plates, replenishes different lithium to different distribution regions, and achieves quantitative and accurate lithium replenishment, which is advantageous in improving the energy density and lifespan of the battery.

[0027] In a fourth aspect, the present application provides a secondary battery including the electrode assembly described above.

[0028] The above-described secondary battery, by using the above-described electrodes, is advantageous in that it can replenish different lithium in different distribution regions, achieve quantitative and accurate lithium replenishment, and improve the energy density and lifespan of the battery.

[0029] In a fifth aspect, the present application provides a power consumption device including the secondary battery described above.

[0030] The above description is merely an outline of the proposed technology of this application. In order to provide a clearer understanding of the technical means of this application, to enable implementation based on the contents of the specification, and to make the above and other objectives, features, and advantages of this application clearer and easier to understand, specific embodiments of this application are given below. [Brief explanation of the drawing]

[0031] To more clearly illustrate the technical concept of the embodiments of this application, the drawings that may be used in the embodiments of this application are briefly described below. However, as is clear, the drawings described below represent only a few embodiments of this application, and those skilled in the art can obtain other drawings based on these without expending any creative effort. [Figure 1] This figure shows a vehicle structure in several embodiments of this application. [Figure 2] This is an exploded view of a battery in some embodiments of this application. [Figure 3] This is a schematic diagram of a partial structure of an electrode plate in several embodiments of this application. [Figure 4] This is a cross-sectional view of the structure of an electrode plate in some embodiments of this application. [Figure 5] This is flowchart 1 of the electrode plate manufacturing method in some embodiments of this application. [Figure 6] This is flowchart 2 of the electrode manufacturing method in some embodiments of this application. [Modes for carrying out the invention]

[0032] The following describes in detail embodiments of the technical proposal of this application, with accompanying drawings. The following embodiments are provided for illustrative purposes only to more clearly illustrate the technical proposal of this application and do not limit the scope of protection of this application.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Terms used herein are used solely to describe specific embodiments and are not intended to limit this application. The terms “including,” “having,” and any variations thereof in the description of the specification, claims, and drawings herein are intended to cover the non-exclusive “including.”

[0034] In the description of the embodiments of this application, terms such as “first,” “second,” etc., are used solely for the purpose of distinguishing different subjects and are not to be understood as explicitly or suggesting relative importance, or implicitly indicating the number, specific order, or primary / secondary relationship of the indicated technical features. In the description of the embodiments of this application, “multiple” means two or more unless specifically defined otherwise.

[0035] Where the “Examples” are referred to in this specification, it means that certain features, structures, or characteristics described in conjunction with the Examples may be included in at least one Example of this Application. The occurrence of the phrase at each location in the Specification does not necessarily refer to the same Example, nor does it mean that each Example is mutually exclusive or alternative to the others. Those skilled in the art will understand, both explicitly and implicitly, that the Examples described herein may be combined with other Examples.

[0036] In the description of the embodiments of this application, the term "and / or" merely describes the relationship between related objects and indicates that three relationships may exist. For example, A and / or B may represent A alone, a combination of A and B, or B alone. In addition, the letter " / " in the text generally indicates that the preceding and succeeding related objects are in an "or" relationship.

[0037] In the description of the embodiments of this application, the term "multiple" means two or more (including two), similarly, "multiple groups" means two or more groups (including two groups), and "multiple pieces" means two or more pieces (including two pieces).

[0038] In the description of the embodiments of this application, the orientations or positional relationships indicated by technical terms such as "center," "vertical," "horizontal," "length," "width," "thickness," "top," "bottom," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inside," "outside," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" are based on the orientations or positional relationships shown in the drawings and are intended for the convenience or simplification of the description of the embodiments of this application. They do not indicate or imply that the referred devices or elements have a specific orientation or need to be constructed and operated in a specific orientation, and should not be understood as limiting the embodiments of this application.

[0039] In the description of the embodiments of this application, unless otherwise explicitly defined or limited, the technical terms “attached,” “connected,” “connected,” and “fixed” should be understood in a broad sense, for example, they may be fixedly connected, detachably connected, integrated, mechanically connected, electrically connected, directly connected, indirectly connected via an intermediate medium, or be internal communication between the two elements or an interaction relationship between the two elements. Those skilled in the art will be able to understand the specific meaning of the above terms in the embodiments of this application, depending on the specific circumstances.

[0040] Currently, the applications of power batteries are expanding rapidly due to the development of market conditions. Power batteries are widely used not only in energy storage power systems such as hydroelectric, thermal, wind, and solar power plants, but also in electric transportation such as electric bicycles, electric motorcycles, and electric vehicles, as well as in military equipment and aerospace. As the application fields of power batteries expand, the market demand for them is also constantly growing.

[0041] The applicant has observed that during the initial charging process of a lithium-ion battery, the organic electrolyte undergoes reductive decomposition on the negative electrode surface, such as graphite, forming a solid electrolyte phase interface film. This film permanently consumes a large amount of lithium from the positive electrode, resulting in a low Coulomb efficiency during the first cycle and a decrease in the capacity and energy density of the lithium-ion battery.

[0042] To address the problem of reduced battery capacity and energy density due to irreversible lithium depletion during the cyclic process, the applicant discovered that lithium can be added to the battery through lithium replenishment methods such as lithium strip rolling, thereby replenishing lithium ions and improving energy density and lifespan. However, in coating processes such as transfer coating, a slurry is transferred to a current collector such as copper foil or aluminum foil by steel rolls, forming a coating area of ​​uniform thickness. This is then baked in a tunnel oven. However, during the baking process, the solid content at the edges of the coating area on the current collector increases faster than in the intermediate area, and the surface tension of the slurry at the edges of the coating area is greater than that of the intermediate part. As a result, the slurry flows towards the edges, causing a "thick edge" phenomenon to appear on the electrode plate after baking.

[0043] To avoid thick edges on the electrode plates, the edges are usually thinned using equipment such as a slimming device or a transfer coater. However, thinning results in different amounts of active material in different distribution regions on the electrode plate, such as the broad area in the middle of the plate and the area where the edge is thinned. If the same amount of lithium replenishment is applied to the electrode plate, the amount of lithium released by the active material is lower in the area where the edge is thinned and lower in the broad area in the middle. As a result, with the same amount of lithium replenishment, the amount of lithium replenishment in the thinned area may be too high, leading to lithium deposition problems, or the amount of lithium replenishment in the broad area in the middle may be too low, resulting in capacity loss or failure to meet expectations for improved lifespan.

[0044] Based on the above considerations, in order to solve the problem of not being able to accurately replenish lithium due to the amount of active material in different distribution regions, the inventors diligently conducted research and found that the average weight of active material per unit area of ​​the active layer is M A A plate was designed in which V0 is the sum of the internal volumes of the lithium replenishment space covered by the projection in the thickness direction of the current collection structure in the distribution region. A This is M in the second distribution region. AThe corresponding V0 in the first distribution region is smaller than the corresponding V0 in the second distribution region.

[0045] In the process of setting up lithium replenishment spaces, the sum V0 of the pore volumes of the lithium replenishment spaces corresponding to each distribution region is controlled in a positive correlation based on the average weight change of the active material in at least two distribution regions. That is, the sum of the volumes in the corresponding lithium replenishment spaces in the second distribution region is large, and the sum of the volumes in the corresponding lithium replenishment spaces in the first distribution region is small. By replenishing different lithium to different distribution regions in this way, quantitative and accurate lithium replenishment is achieved. This avoids problems such as lithium deposition occurring due to excessive lithium replenishment in the first distribution region or capacity loss or failure to achieve expected life improvement due to insufficient lithium replenishment in the second distribution region, under the assumption of the same lithium replenishment amount, and is advantageous in improving the energy density and lifespan of the battery.

[0046] The battery cells disclosed in the embodiments of this application may, but are not limited to, use in power-consuming devices such as vehicles, ships, or aircraft. A power supply system comprising the battery cells, batteries, etc. disclosed in this application can be used to constitute such power-consuming devices, which is advantageous for replenishing different lithium to different distribution areas, achieving quantitative and accurate lithium replenishment, and improving the energy density and lifespan of the battery.

[0047] Embodiments of this application provide a power consumption device that uses a battery as a power source, which may be, but is not limited to, a mobile phone, tablet, laptop computer, electric toy, electric tool, battery car, electric vehicle, steamship, or aerospace aircraft. Here, electric toys may include stationary or mobile electric toys, such as game consoles, electric vehicle toys, electric steamship toys, electric airplane toys, etc., and aerospace aircraft may include airplanes, rockets, space shuttles, or spacecraft.

[0048] For the sake of explanation, the following embodiments will be described using the example that the power consumption device in one embodiment of this application is a vehicle 1000.

[0049] Referring to Figure 1, which is a schematic diagram of the structure of a vehicle 1000 according to some embodiments of the present application, the vehicle 1000 may be a fuel oil vehicle, a gas vehicle, or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle, or an extended-range electric vehicle. A battery 100 is installed inside the vehicle 1000, and the battery 100 can be installed at the bottom, top, or rear of the vehicle 1000. The battery 100 can be used to supply power to the vehicle 1000, for example, the battery 100 can be the operating power source for the vehicle 1000. The vehicle 1000 may further include a controller 200 and a motor 300, the controller 200 for controlling the battery 100 to supply power to the motor 300, for example, to meet the operating power demands of starting, navigation, and driving the vehicle 1000.

[0050] In some embodiments of this application, the battery 100 can function not only as an operating power source for the vehicle 1000 but also as a drive power source for the vehicle 1000 in order to provide the vehicle 1000 with driving force in place of or in place of fuel or natural gas.

[0051] Referring to Figure 2, which is an exploded view of a battery 100 provided by some embodiments of the present application, the battery 100 includes a housing 110 and battery cells 120 housed within the housing 110, where the housing 110 provides a housing space for the battery cells 120 and can take various forms. In some embodiments, the housing 110 includes a first portion 111 and a second portion 112, the first portion 111 and the second portion 112 overlapping each other, and together defining a housing space for housing the battery cells 120. The second portion 112 may be a hollow structure with one end open, and the first portion 111 may be a plate-like structure that overlaps the open side of the second portion 112 so that the first portion 111 and the second portion 112 together define a housing space. Both the first part 111 and the second part 112 are hollow structures with one side open, and the open side of the first part 111 may be fitted over the open side of the second part 112. Of course, the housing 110 formed by the first part 111 and the second part 112 can have a variety of shapes, such as cylindrical or rectangular parallelepiped.

[0052] In battery 100, there may be multiple battery cells 120, and the multiple battery cells 120 may be connected in series, parallel, or series-parallel, where series-parallel means that there are both series and parallel connections among the multiple battery cells 120. After directly connecting the multiple battery cells 120 in series, parallel, or series-parallel, the entire assembly consisting of the multiple battery cells 120 can be housed in the housing 110. Of course, battery 100 may also be in a form in which multiple battery cells 120 are connected in series, parallel, or series-parallel to form a battery 100 module, and then multiple battery 100 modules are connected in series, parallel, or series-parallel and integrated, and housed in the housing 110. Battery 100 may also include other structures; for example, battery 100 may further include busbar members for electrically connecting the multiple battery cells 120.

[0053] Here, each battery cell 120 may be a secondary battery 100 or a primary battery 100, and may be a lithium-sulfur battery 100, a sodium-ion battery 100, or a magnesium-ion battery 100, but is not limited thereto. The battery cell 120 may be cylindrical, flattened, rectangular, or have other shapes.

[0054] Referring to some embodiments of this application, specifically Figure 3, this application provides an electrode plate 10. The electrode plate 10 has a current collection structure 11 and two active layers 12. The two active layers 12 are provided on opposing sides of the current collection structure 11 in the thickness direction. The current collection structure 11 is provided with several lithium replenishment spaces 13 that lead to one side of the active layer 12. A lithium replenishment agent is contained within the lithium replenishment spaces 13. In a distribution region 14 on the active layer 12 communicating with the lithium replenishment spaces 13, the average weight of the active material per unit area of ​​the active layer 12 is M A Let V0 be the sum of the volumes in the lithium replenishment space 13 covered by the projection of the current collection structure 11 in the thickness direction of the distribution region 14. The distribution region 14 includes at least a first distribution region 14a and a second distribution region 14b. Here, M in the first distribution region 14a A This is M in the second distribution region 14b. A The corresponding V0 in the first distribution region 14a is smaller than the corresponding V0 in the second distribution region 14b.

[0055] The current collection structure 11 is a component or part that not only supports the active material but also collects and outputs the current generated from the electrode active material, and this component or part may have a single-layer or multi-layer structure. The material of the current collection structure 11 is diverse and includes, but is not limited to, metallic materials such as copper, aluminum, nickel, and stainless steel. Of course, it may also be a semiconductor material such as carbon, or a composite material such as conductive resin, titanium-nickel shape memory alloy, or carbon-coated aluminum foil.

[0056] The active layer 12 refers to the active material coated on the current collector structure 11, and its specific components differ depending on the polarity of the electrode plates 10. For example, the active material on the positive electrode plate may be, but is not limited to, lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, lithium iron phosphate, ternary materials, etc. The active material on the negative electrode plate may be, but is not limited to, graphite, lithium titanate, silicon oxide, etc.

[0057] A lithium replenisher is a substance that can replenish lithium ions inside the battery 100. For example, if the electrode plate 10 is a negative electrode plate, the lithium replenisher may be, but is not limited to, lithium foil, lithium powder, lithium silicide powder, etc. If the electrode plate 10 is a positive electrode plate, the lithium replenisher may be, but is not limited to, Li2NiO2, Li5FeO4, Li2O, etc. Furthermore, the method by which the lithium replenisher is formed in the lithium replenishment space 13 may be rolling or deposition, and the deposition method may be a magnetron sputter deposition method, etc., but is not limited to these.

[0058] The lithium replenishment space 13 refers to a space on the current collector structure 11 that can accommodate lithium replenishment material, and is, for example, a perforated or grooved structure, or a concave structure. If the lithium replenishment space 13 is a concave structure on the current collector structure 11, the surface of the current collector structure 11 may be wavy. The active layer 12 has multiple distribution regions 14 on the side facing the current collector structure 11, and the average weight of the active material per unit area differs in at least two of the distribution regions 14. For example, if the edge of the electrode plate 10 is thinned, the average weight of the active material per unit area at the edge is generally smaller than the average weight of the active material in the central distribution region 14 of the electrode plate 10. Here, factors that affect the average weight of the active material per unit area may include, but are not limited to, the type of active material, the thickness of the active material, and the density of the active material. Therefore, when providing the lithium replenishment space 13, the average weight of the active material per unit area can be used as a reference to more comprehensively consider the effect on lithium replenishment, and the amount of lithium replenishment can be made more accurate. To facilitate understanding, see Figure 4For example, the thickness direction of the current collection structure 11 is as shown in Figure 4 In this case, it is the direction indicated by one of the arrows S.

[0059] The sum of the internal volumes of the lithium replenishment spaces 13 covered by the projection of the current collection structure 11 in the thickness direction for each distribution region 14 should be understood as the projection of the current collection structure 11 in the thickness direction for each distribution region 14 in the same active layer 12, and the sum of the internal volumes of the lithium replenishment spaces 13 in this portion should be denoted as V0. The size of the internal volume of the lithium replenishment spaces 13 can determine the total amount of lithium replenishment corresponding to the corresponding distribution region 14. Note that the size of the sum of the internal volumes of the lithium replenishment spaces 13 corresponding to each distribution region 14 may be influenced by, but is not limited to, the depth of, lithium replenishment spaces 13, the opening area of ​​lithium replenishment spaces 13, or the distribution density of lithium replenishment spaces 13.

[0060] The fact that the lithium replenishment space 13 can connect to the active layer 12 means that one end of the lithium replenishment space 13 communicates with the active layer 12, allowing the lithium replenisher in the lithium replenishment space 13 to penetrate into the active layer 12 and achieve a lithium replenishment effect. Here, the method for realizing that the lithium replenishment space 13 connects to the active layer 12 may be to open a space on the side of the current collection structure 11 facing the active layer 12. Alternatively, one end of the lithium replenishment space 13 may be extended into the interior of the active layer 12.

[0061] The sum of the volumes within the lithium replenishment spaces 13 refers to the sum of the internal volumes of multiple lithium replenishment spaces 13 corresponding to a single distribution region 14. There are several methods for determining the size of the volume of a single lithium replenishment space 13, for example, as follows: First, the opening area of ​​the lithium replenishment space 13 is obtained, then the depth of the lithium replenishment space 13 is obtained, and finally, the product of the opening area and the depth is taken. The obtained data is the volume of a single lithium replenishment space 13.

[0062] The shape of the lithium replenishment space 13 can be designed in various ways, such as one or more of the following: circular, square, rhombus, triangular, etc. Furthermore, the opening areas of all lithium replenishment spaces 13 may be the same, or they may not be the same; for example, the opening areas of all lithium replenishment spaces 13 may differ. To ensure the diffusion of lithium replenishment is as uniform as possible, the opening area of ​​the lithium replenishment space 13 must be as small as possible. For example, if the lithium replenishment space 13 is circular or square, its diameter or width may be 5 μm to 1 mm. In some embodiments, the diameter or width of the lithium replenishment space 13 may be in the range of 30 μm to 200 μm. For example, the diameter or width of the lithium replenishment space 13 may be, but not limited to, 30 μm, 50 μm, 70 μm, 90 μm, 100 μm, 120 μm, 150 μm, 180 μm, or 200 μm.

[0063] The electrode plate 10 of this application may have a lithium replenishment space 13 on one side of the current collection structure 11, or it may have lithium replenishment spaces 13 on both sides of the current collection structure 11. If the lithium replenishment space 13 is provided on only one side of the current collection structure 11, the electrode plate 10 will have a lithium replenishment effect on one side.

[0064] A lithium replenishment space 13 is provided in the current collection structure 11, and the lithium replenishment space 13 is located within one side of the active layer 12. Lithium is replenished in the battery 100 using the lithium replenishment agent in the lithium replenishment space 13, offsetting irreversible lithium loss during the cycle process and improving the total capacity and energy density of the battery 100. The average weight M of the corresponding active material in at least two distribution regions 14 on the active layer 12. ABecause they differ, this application controls the sum V0 of the pore volumes of the lithium replenishment spaces 13 corresponding to each distribution region 14 in a positive correlation with respect to the average weight change of the active material in the different distribution regions 14. That is, the sum of the volumes in the corresponding lithium replenishment spaces 13 in the second distribution region 14b is large, and the sum of the volumes in the corresponding lithium replenishment spaces 13 in the first distribution region 14a is small. By replenishing different lithium to different distribution regions 14 in this way, quantitative and accurate lithium replenishment is achieved, and under the assumption of the same amount of lithium replenishment, it is advantageous to improve the energy density and lifespan of the battery 100 by avoiding problems such as lithium deposition occurring due to too much lithium replenishment in the first distribution region 14a, or capacity loss or failure to improve lifespan as expected due to too little lithium replenishment in the second distribution region 14b, thereby improving the energy density and lifespan of the battery 100.

[0065] According to some embodiments of this application, referring to Figure 4, the depth of the lithium replenishment space 13 is denoted as d. The thickness of the active layer 12 corresponding to the location of the lithium replenishment space 13 is denoted as h. Here, h in the first distribution region 14a is smaller than h in the second distribution region 14b, and the corresponding d in the first distribution region 14a is smaller than the corresponding d in the second distribution region 14b.

[0066] The thickness of the active layer 12 corresponding to the location of the lithium replenishment space 13 can be understood as the path length passing through the active layer 12, extending from the location of the lithium replenishment space 13 along the thickness direction of the current collection structure 11 to the surface of the active layer 12, and the corresponding thickness of the active layer 12.

[0067] When the thickness of the active layer 12 is based on spatial placement reference, it should be ensured as much as possible that the active layer 12 on one side of the current collection structure 11 is made of the same type of active material, and that the actual pressure of the active layer 12 on the current collection structure 11 is also the same.

[0068] In different distribution regions 14, by referencing the thickness of the active layer 12, the control of the parameter for the sum of volumes in the lithium replenishment space 13 is converted into control of the depth of the lithium replenishment space 13, enabling not only quantitative and accurate lithium replenishment effects but also simplifying the processing process of the lithium replenishment space 13 and improving the manufacturing efficiency of the electrode plate 10.

[0069] According to some embodiments of this application, the depth d of the lithium replenishment space 13 is

number

[0070] In the inequality, 3860 is the theoretical specific capacity of lithium metal, in units of mAh / g. 0.534 is the density of lithium metal, in units of grams per cubic centimeter (g / cm³). 3 ) is the value. 10000 is the unit conversion value. Furthermore, the ratio of the pore area of ​​all lithium replenishment spaces 13 per unit area should be understood as the ratio of the sum of the cross-sectional areas of all lithium replenishment spaces 13 per unit area to "1".

[0071] In the lithium replenishment process, excessive lithium replenishment can easily lead to lithium deposition in the negative electrode cycle process. Therefore, when designing the depth of the lithium replenishment space 13, it is necessary to set an upper limit on the depth. Furthermore, if the depth of the lithium replenishment space 13 does not satisfy the above inequality during the manufacturing process, the depth of the lithium replenishment space 13 can be made to satisfy this inequality by increasing the average weight of the active material per unit area of ​​the negative electrode, for example, by coating the corresponding distribution region 14 with the active material.

[0072] By setting an upper limit on the depth of the lithium replenishment space 13, excess lithium is replenished, preventing lithium deposition due to the negative electrode side cycle process, which is advantageous in improving the safety of the battery 100.

[0073] According to some embodiments of this application, the ratio P of the opening area of ​​all lithium replenishment spaces 13 per unit area satisfies the relationship 10% ≤ P ≤ 50%.

[0074] In a unit area, the ratio of the opening area of ​​the lithium replenishment space 13 should not be too large. If the ratio of the area of ​​the lithium replenishment space 13 is too large, the hollow portion of the current collection structure 11 will increase, seriously affecting its electron conduction function. In some embodiments, the ratio P of the total opening area of ​​the lithium replenishment space 13 per unit area may be, but is not limited to, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, etc.

[0075] The ratio P of the opening areas of all lithium replenishment spaces 13 within a unit area is controlled between 10% and 50%, ensuring that there is sufficient space to accommodate the lithium replenishment agent. The ratio of the opening areas of the lithium replenishment spaces 13 is rationally controlled to ensure the stability of the electron conduction function of the current collection structure 11.

[0076] According to some embodiments of this application, the depth d of the lithium replenishment space 13 is

number

[0077] Here, CE C This is the initial Coulomb efficiency of the positive electrode active material, CE A This is the initial Coulomb efficiency of the negative electrode active material, C A This is the initial lithium storage capacity of the negative electrode active material in mAh / g.

[0078] The initial Coulomb efficiency of the positive electrode active material is the ratio of the initial lithium absorption capacity mAh / g of the positive electrode active material to the initial lithium release capacity mAh / g of the positive electrode active material. The initial Coulomb efficiency of the negative electrode active material is the ratio of the initial lithium release capacity mAh / g of the negative electrode active material to the initial lithium absorption capacity mAh / g of the negative electrode active material. Here, the initial lithium release and absorption capacity can be tested, for example, by manufacturing a button battery. For example, the positive and negative electrodes are prepared as slurries by a normal formulation, one side of the electrode plate 10 is coated, cut into button battery tablets, and lithium metal pieces are used to form the button battery half-cells. The positive electrode plate is tested using a 0.1C / 0.1C charge / discharge ratio. The positive electrode material button battery is first charged and then discharged. The initial charge capacity is the initial lithium release capacity of the positive electrode active material, and the initial discharge capacity is the initial lithium absorption capacity of the positive electrode active material. The negative electrode plate was tested using a charge / discharge ratio of 0.1C / 0.05C. The negative electrode material button cell was first discharged and then charged. The initial discharge capacity was the initial lithium absorption capacity of the negative electrode active material, and the initial charge capacity was the initial lithium release capacity of the negative electrode active material.

[0079] The depth d of the lithium replenishment space 13 is

number

[0080] The depth d of the lithium replenishment space 13 is

number

number

number

number

number

[0081] By setting a lower limit for the depth of the lithium replenishment space 13, the lithium replenishment space 13 can be filled with a lithium replenisher (e.g., metallic lithium), thereby enabling the full utilization of the positive electrode active material capacity and effectively improving the energy density.

[0082] According to some embodiments of this application, referring to Figure 4, in at least one active layer 12, the lithium replenishment spaces 13 are spaced apart such that the distance between any two adjacent lithium replenishment spaces 13 is equal.

[0083] The fact that the spacing between any two adjacent lithium replenishment spaces 13 is equal indicates that the lithium replenishment spaces 13 on one side of the current collection structure 11 are arranged at equal intervals, i.e., the distribution density of the lithium replenishment spaces 13 is constant. In this case, the magnitude of the sum of the volumes within the corresponding lithium replenishment spaces 13 in each distribution region 14 depends mainly on the depth of the lithium replenishment space 13, and therefore V0 and M A When controlling the relationship of change between d and h, it can be effectively converted into a relationship of change between d and h.

[0084] In at least one of the active layers 12, the present application shows that in the electrode plate 10, several lithium replenishment spaces 13 can be provided in only one of the active layers 12. Of course, several lithium replenishment spaces 13 may be provided correspondingly in both active layers 12.

[0085] By uniformly distributing the lithium replenishment space 13 in the active layer 12 on either side and controlling the depth of the lithium replenishment space 13, it is advantageous that a quantitative and accurate lithium replenishment effect can be achieved. At the same time, by uniformly distributing the lithium replenishment space 13, the diffusion of lithium charge becomes uniform, improving the performance of the battery 100.

[0086] According to some embodiments of this application, referring to Figure 4, the current collection structure 11 includes at least one current collector 11a in the thickness direction of the current collection structure 11. At least one of the current collectors 11a, which are provided with an active layer 12, has a lithium replenishment space 13 that penetrates it.

[0087] The current collector 11a is a component or part that not only carries the active material but also collects and outputs the current generated from the electrode active material, and is the core structure that constitutes the current collector structure 11. There may be one current collector 11a or multiple current collectors. If there is one current collector 11a, the two active layers 12 are provided on opposing sides of the same current collector 11a. If there are multiple current collectors 11a, the two active layers 12 are provided on the current collectors 11a located at the outermost ends in the thickness direction of the current collector structure 11. Also, if there are multiple current collectors 11a, the multiple current collectors 11a are stacked in the thickness direction of the current collector structure 11.

[0088] There are multiple design configurations for the lithium replenishment space 13 on the current collector 11a. For example, if there is only one current collector 11a, the lithium replenishment space 13 that penetrates the current collector can extend to one side, or a portion of the lithium replenishment space 13 can extend toward the active layer 12 on one side, while the other portion of the lithium replenishment space 13 extends toward the active layer 12 on the other side. If there are multiple current collectors 11a, the lithium replenishment space 13 can penetrate only one current collector 11a, and this lithium replenishment space 13 can extend toward the corresponding active layer 12. Alternatively, the lithium replenishment space 13 can penetrate both of the two outermost current collectors 11a.

[0089] By designing the current collection structure 11 as at least one current collector 11a, not only is electron conduction facilitated, but it also becomes easier to create holes in the current collection structure 11, allowing the lithium replenisher to be stably deposited in the lithium replenishment space 13.

[0090] According to some embodiments of this application, referring to Figure 4, the current collector 11a includes two. Two active layers 12 are provided on the opposite sides of the two current collectors 11a, respectively. A lithium replenishment space 13 is provided through both current collectors 11a.

[0091] When the two current collectors 11a penetrate the lithium replenishment space 13, one end of the lithium replenishment space 13 on each current collector 11a extends into the interior of the corresponding active layer 12. There may be multiple distributions of the lithium replenishment space 13 on the current collectors 11a; for example, the lithium replenishment space 13 may be uniformly distributed on the current collectors 11a, or the distribution density of the lithium replenishment space 13 may differ depending on the thickness of the active layer 12; for example, a thicker active layer 12 may have a corresponding distribution of more lithium replenishment spaces 13, and a thinner active layer 12 may have a corresponding distribution of fewer lithium replenishment spaces 13.

[0092] There are multiple correspondences in the distribution between the lithium replenishment spaces 13 on the two current collectors 11a. For example, the distribution of the lithium replenishment space 13 on one current collector 11a and the distribution of the lithium replenishment space 13 on the other current collector 11a are completely misaligned, meaning that the lithium replenishment space 13 on one side and the lithium replenishment space 13 on the other side are not in communication. Alternatively, the distribution of the lithium replenishment space 13 on one current collector 11a and the distribution of the lithium replenishment space 13 on the other current collector 11a are completely aligned, meaning that the lithium replenishment space 13 on one side and the lithium replenishment space 13 on the other side are in communication. If the lithium replenishment spaces 13 on the two current collectors 11a are kept in communication with each other, the lithium replenisher in the lithium replenishment spaces 13 on the two current collectors 11a are shared, meaning that the lithium replenisher in the lithium replenishment space 13 on one side can be used to replenish the lithium in the active layer 12 on the other side.

[0093] The means of connecting the two current collectors 11a may be welding, bonding, etc., but are not limited to these. For example, in the manufacturing process, two current collectors 11a coated with the active layer 12 are bonded together on the side having the lithium replenishment space 13. After bonding, the periphery of the two current collectors 11a is connected by welding, bonding, etc.

[0094] Each of the two current collectors 11a has a lithium replenishment space 13 that penetrates through it, enabling effective lithium replenishment to both the active layers 12 on both sides, and further improving the energy density and cycle life of the battery 100.

[0095] According to some embodiments of this application, referring to Figure 4, the current collector structure 11 further includes at least one lithium replenishment layer 15. The lithium replenishment layer 15 is located between two current collectors 11a.

[0096] The lithium replenishment layer 15 is a material that can replenish lithium ions inside the battery 100. For example, if the electrode plate 10 is the negative electrode plate, the lithium replenishment layer 15 may be a metallic lithium layer or the like, but is not limited to these. If the electrode plate 10 is the positive electrode plate, the lithium replenishment layer 15 may be Li2NiO2, Li5FeO4, or Li2O, but is not limited to these.

[0097] The lithium replenishment layer 15 may be one or more between the two current collectors 11a. If there are two lithium replenishment layers 15, one lithium replenishment layer 15 is bonded to the side of one current collector 11a that is facing away from the active layer 12. The other lithium replenishment layer 15 is bonded to the side of the other current collector 11a that is facing away from the active layer 12.

[0098] By providing at least one lithium replenishment layer 15 between the two current collectors 11a, the amount of lithium replenishment can be increased, effectively improving the cycle life of the battery 100.

[0099] According to some embodiments of this application, referring to Figure 4, the lithium replenishment space 13 is a lithium replenishment hole 13a. The lithium replenishment hole 13a extends along the thickness direction of the current collection structure 11 into the active layer 12 on either side.

[0100] The fact that the lithium holes 13a extend into the active layer 12 in the thickness direction of the current collection structure 11 is understood to mean that one end of the lithium replenishment space 13 of the lithium holes is located inside the active layer 12 and does not penetrate the active layer 12, i.e., it resembles a blind via structure.

[0101] By designing the lithium replenishment space 13 as a lithium replenishment hole 13a and extending one end of the lithium replenishment hole 13a into the interior of the active layer 12, the manufacturing process of the electrode plate 10 is simplified, which is also advantageous for controlling the corresponding lithium replenishment amount in different distribution regions 14, thereby achieving more accurate lithium replenishment.

[0102] According to some embodiments of this application, referring to Figure 4, the first distribution area 14a is extended and installed around the periphery of the second distribution area 14b.

[0103] The first distribution region 14a is relatively close to the edge of the electrode plate 10, while the second distribution region 14b is relatively close to the middle of the electrode plate 10. On the other hand, the first distribution region 14a has a linear annular structure.

[0104] Average weight M of active material near the edge of electrode plate 10 A This is the average weight M of the active material near the center of the electrode plate 10. A Being smaller and designed in this way is advantageous in solving the problem of bulging caused by the edges of the electrode plate 10 being too thick.

[0105] According to some embodiments of this application, referring to Figure 5, a method for manufacturing an electrode plate 10 includes the following steps:

[0106] In the S100, there are two single-sided electrode plates 1 6 Provided here, single-sided electrode plate 1 6 is It includes a current collector 11a and an active layer 12 provided on one side of the current collector 11a.

[0107] In S200, at least one single-sided electrode plate 1 6 Lithium replenishment holes 13a are provided in the current collector 11a that extend into the active layer 12, and the average weight M of the active material per unit area in at least two distribution regions 14 on the active layer 12 A The sum of the volumes inside the lithium replenishment holes 13a corresponding to M in the first distribution region 14a is given by V0. A M in the second distribution region 14b AThe control is performed to make it smaller, and to satisfy the condition that the corresponding V0 in the first distribution region 14a is smaller than the corresponding V0 in the second distribution region 14b, where the distribution region 14 includes both the first distribution region 14a and the second distribution region 14b.

[0108] In the S300, lithium replenishment material is deposited in all lithium replenishment holes 13a.

[0109] In the S400, there are two single-sided electrode plates 1 6 The sides facing away from the active layer 12 are bonded together.

[0110] In step S100, one side of the electrode plate 1 6 is It can be substantially understood that the structure of the electrode plate 10 includes half of the structure, namely the current collector 11a and the active layer 12 coated on one side of the current collector 11a, in which case the active layer 12 is not coated on the other side of the current collector 11a. Single-sided electrode plate 1 6 The manufacturing process does not have to be included in the method of manufacturing the electrode plate 10 of this application, and may be completed directly by a supplier or other process. Of course, single-sided electrode plate 1 6 The manufacturing process may include the manufacturing method of the electrode plate 10 of this application. For example, an active material is coated on one side of the current collector 11a. After coating, the current collector 11a is compressed with a roll press (cold press) to rearrange and densify the powder. Also, single-sided electrode plate 1 6 To avoid the thick edges, one side of the electrode plate 1 6 When the edges are thinned, the average weight of the active material in different distribution regions 14 on the active layer 12 becomes non-uniform.

[0111] In step S200, there are several methods for creating holes in the current collector 11a, such as laser drilling and roller pin drilling.

[0112] In step S300, when depositing lithium replenishment material in the lithium replenishment hole 13a, the lithium replenishment material should be deposited completely into the lithium replenishment hole 13a, that is, so that the lithium replenishment material in the hole is flush with one end of the lithium replenishment hole 13a on the current collector 11a. The method of depositing the lithium replenishment material may be, but is not limited to, lithium strip rolling or magnetron sputtering.

[0113] Step S400 uses two single-sided electrode plates 1 6 The sides facing the active layer 12 are bonded together, forming a perforated single-sided electrode plate 1 6 It can be understood that the surfaces are assembled by bonding them together. Thus, in the subsequent manufacturing of the electrode assembly, one single-sided electrode plate 6 top Each of the active layers 12 faces an isolation member (e.g., a separator).

[0114] single surface Plate 1 6 The required electrode plates 10 are manufactured by bonding them together, significantly simplifying the manufacturing process. At the same time, it is easy to create holes in the electrode plates 10, ensuring that the lithium replenisher is stably deposited in the lithium replenishment holes 13a, thereby achieving a quantitative and accurate lithium replenishment effect. The average weight M of the corresponding active material in different distribution regions 14 on the active layer 12. ATherefore, this application controls the sum V0 of the internal volumes of lithium replenishment holes 13a corresponding to each distribution region 14 in a positive correlation with respect to the average weight change of the active material in different distribution regions 14. That is, the sum of the internal volumes of the corresponding lithium replenishment holes 13a in the second distribution region 14b is relatively large, and the sum of the internal volumes of the corresponding lithium replenishment holes 13a in the first distribution region 14a is relatively small. By replenishing different lithium to different distribution regions 14 in this way, quantitative and accurate lithium replenishment is achieved, and under the assumption of the same lithium replenishment amount, problems such as lithium deposition occurring due to too much lithium replenishment in the first distribution region 14a (e.g., thinning region) or capacity loss or failure to meet expectations in life improvement due to too little lithium replenishment in the second distribution region 14b (e.g., wide surface region) are avoided, thereby improving the energy density and lifespan of the battery 100.

[0115] According to some embodiments of this application, with reference to Figure 6, the average weight M of the active substance per unit area in different distribution regions 14 on the active layer 12 A Step S200, which controls the sum V0 of the internal volumes of the lithium replenishment holes 13a corresponding to the current collection holes 14 to change in a positive correlation, includes Step S210 of obtaining the thickness h of the active layer 12 in different distribution regions 14, Step S220 of uniformly opening a plurality of lithium replenishment holes 13a in the current collection body 11a, and Step S230 of controlling the depth d of the lithium replenishment holes 13a in the projected region on the current collection body 11a of each distribution region 14 such that h in the first distribution region 14a is smaller than h in the second distribution region 14b, and d corresponding in the first distribution region 14a is smaller than d corresponding in the second distribution region 14b.

[0116] In step S220, uniformly opening multiple lithium replenishment holes 13a should be understood as having equal spacing between any two adjacent lithium replenishment holes 13a. The sum of the internal volumes of the lithium replenishment holes 13a corresponding to each distribution region 14 may be influenced by factors such as the depth of the lithium replenishment holes 13a and the distribution density of the lithium replenishment holes 13a, but is not limited to these. Therefore, the distribution density of the lithium replenishment holes 13a is controlled to be constant, and in this case, the sum of the internal volumes of the corresponding lithium replenishment holes 13a in each distribution region 14 mainly depends on the depth of the lithium replenishment holes 13a, thereby affecting V0 and M A When controlling the relationship of change between d and h, it can be effectively converted into a relationship of change between d and h.

[0117] By using the thickness of the active layer 12 as a reference, the control of the parameter for the sum of the internal volumes of the lithium replenishment holes 13a is converted to control the depth of the lithium replenishment holes 13a, which not only enables quantitative and accurate lithium replenishment, but also simplifies the processing process of the lithium replenishment holes 13a and improves the manufacturing efficiency of the electrode plate 10.

[0118] According to some embodiments of this application, the depth d of the lithium replenishment hole 13a is

number

[0119] In the lithium replenishment process, excessive lithium replenishment can easily lead to lithium deposition during the negative electrode cycle process. Therefore, when designing the depth of the lithium replenishment holes 13a, it is necessary to set an upper limit on the hole depth. Furthermore, if the hole depth of the lithium replenishment holes 13a does not satisfy the above inequality during the manufacturing process, the hole depth of the lithium replenishment holes 13a can be made to satisfy this inequality by increasing the average weight of the active material per unit area of ​​the negative electrode, for example, by coating the corresponding distribution region 14 with the active material.

[0120] Setting an upper limit on the depth of the lithium replenishment hole 13a is advantageous in improving the safety performance of the battery 100 by replenishing excess lithium and avoiding lithium deposition due to the negative electrode side cycle process.

[0121] According to some embodiments of this application, the depth d of the lithium replenishment hole 13a is

number

[0122] The depth d of the lithium replenishment hole 13a is

number

[0123] The depth d of the lithium replenishment hole 13a is

number

number

number

number

number

[0124] By setting a lower limit for the depth of the lithium replenishment holes 13a, the lithium replenishment holes 13a can be filled with a lithium replenisher (e.g., metallic lithium), enabling the full utilization of the positive electrode active material capacity and effectively improving energy density.

[0125] The object, technical solution, and advantages of this application will be described using the following specific examples for the sake of brevity, but this application is not limited to these examples. The examples described below are merely preferred embodiments of this application, useful for explaining this application, and should not be construed as limiting the scope of the invention. It should be noted that any modifications, equivalents, and improvements made within the spirit and principles of this application are included in the scope of protection of this application.

[0126] To better explain this application, the contents of this application will be further described below, along with examples. Specific examples are shown below.

[0127] In the same chemical system (i.e., the current collectors 11a of the positive and negative electrodes are of the same type), the effect of the depth d of the lithium replenishment hole 13a on the number of cycles of the battery 100 is as follows:

[0128] Comparative Example 1 Negative electrode plate: High silicon is used as the negative electrode current collector 11a, and the average weight M of the active material per unit area in the first distribution region 14a at the edge of the negative electrode is A is 0.0075 g / cm³ 2 The average weight M of the active material per unit area in the second distribution region 14b of the negative electrode edge is A is 0.0100 g / cm³ 2 Therefore, the initial lithium storage capacity (charge gram capacity) of the active material is C A The capacity is 800mAh / g, and the initial negative electrode effective capacity (initial discharge capacity / initial charge capacity) is 80%.

[0129] The ratio P of the pore area of ​​lithium replenishment holes 13a per unit area is set to 50%,

number

[0130] In this embodiment, the hole depth corresponding to the second distribution region 14b is set to 0 μm (That is, it is designed so that no holes are drilled, and the hole depth corresponding to the first distribution region 14a is set to 0 μm Although the design is to (i.e., no holes are made), for the sake of comparison, the pore area ratio P of the lithium replenishment hole 13a in Comparative Example 1 is also set to 50%.

[0131] Positive plate: As the positive electrode current collector 11a, NCM (a ternary material consisting of three materials: nickel, cobalt, and manganese) is used, and the average weight M of the active material per unit area in the first distribution region 14a at the edge of the positive electrode is C is 0.0240 g / cm³ 2 Therefore, the average weight M of the active material per unit area in the second distribution region 14b of the positive electrode edge. C is 0.0300 g / cm³ 2 Therefore, the initial lithium storage capacity (charge gram capacity) of the active material is C C The capacity is 220mAh / g, and the positive electrode initial effective capacity (initial discharge capacity / initial charge capacity) is 90%.

[0132] Example 1 In the negative electrode plate, the case depth d of the lithium replenishment hole 13a corresponding to the second distribution region 14b is 10 μm The case depth d of the lithium replenishment hole 13a corresponding to the first distribution region 14a is 10 μm Except for the design aspect, it is basically the same as Comparative Example 1.

[0133] Example 2 In the negative electrode plate, the case depth d of the lithium replenishment hole 13a corresponding to the second distribution region 14b is 6.5 μm The case depth d of the lithium replenishment hole 13a corresponding to the first distribution region 14a is 6.5 μm Except for the design aspect, it is basically the same as Comparative Example 1.

[0134] Example 3 The negative electrode plate is basically the same as Comparative Example 1, except that the case depth d of the lithium replenishment hole 13a corresponding to the second distribution region 14b is designed to be 10 μm, and the case depth d of the lithium replenishment hole 13a corresponding to the first distribution region 14a is designed to be 6.5 μm.

[0135] Tables 1-1 and 1-2 below show some of the parameters for each example and comparative example.

[0136] A room-temperature cycle performance test was conducted on the battery 100 manufactured in the above comparative example and example, and the results are shown in Tables 1 and 2. The specific test procedure is as follows.

[0137] The first cycle of charging and discharging battery 100 at 25°C with a constant current of 1C up to 4.25V, then with a constant voltage charge until the current drops to 0.05C, and finally with a constant current discharge of 1C up to 2.8V is defined as the first cycle. The number of cycles required to reduce the capacity retention rate of battery 100 to 80% under the above conditions is as follows. Record do.

[0138] [Table 1-1]

[0139] [Table 1-2]

[0140] Table 1-2 shows that the battery 100 with lithium replenishment holes 13a drilled in the electrode plate 10 exhibits an effective improvement in positive electrode gram capacity compared to the battery 100 without holes in Comparative Example 1. On the other hand, Examples 2 and 3 both show an improvement in the number of cycles with 80% capacity retention compared to the battery 100 in Comparative Example 1. In contrast, the number of cycles in Example 1 decreases, which indicates that the number of cycles does not increase as the depth of the lithium replenishment holes 13a increases, and that it is necessary to ensure that the depth is below the maximum value of the holes in the different distribution regions 14, and that if the depth becomes too deep, lithium deposition is more likely to occur during the cycle.

[0141] Comparing Examples 1-2 with Example 3, the depth d of the lithium replenishment hole 13a is

number

[0142] Furthermore, if the depth d of the lithium replenishment holes 13a changes in a positive correlation with the different distribution regions 14, for example, if the depth d is designed to be larger in the second distribution region 14b and smaller in the first distribution region 14a, the data for the positive electrode gram capacity output and cycle count of the battery 100 will be the best.

[0143] Different chemical systems (i.e., current collectors 11a of the positive and negative electrode plates) different In this type, the effect of the depth d of the lithium replenishment hole 13a on the number of cycles of the battery 100.

[0144] Comparative Example 2 This is basically the same as Comparative Example 1, but at least in the negative electrode plate, the ratio P of the pore area of ​​lithium replenishment holes 13a per unit area is set to 50%, the case depth d of the lithium replenishment holes 13a corresponding to the second distribution region 14b is 5 μm, and the case depth d of the lithium replenishment holes 13a corresponding to the first distribution region 14a is 4 μm They differ in that they are designed for this purpose.

[0145] Comparative Example 3 This is basically the same as Comparative Example 2, but the case depth d of the lithium replenishment hole 13a corresponding to the second distribution region 14b is 20 μm, and the case depth d of the lithium replenishment hole 13a corresponding to the first distribution region 14a is 10 μm They differ in that they are designed for this purpose.

[0146] Comparative Example 4 This is basically the same as Comparative Example 1, but differs in that, at least in the negative electrode plate, the negative electrode current collector 11a is low-silicon.

[0147] Comparative Example 5 This is basically the same as Comparative Example 1, but differs in that, at least in the negative electrode plate, the negative electrode current collector 11a is made of graphite.

[0148] Comparative Example 6 This is basically the same as Comparative Example 1, but differs in that, at least in the positive electrode plate, the positive electrode current collector 11a is LFP (LiFePO4 lithium iron phosphate).

[0149] Example 4 This is basically the same as Example 3 above, but at least in the negative electrode plate, the pore area ratio P of lithium replenishment holes 13a per unit area is set to 30%, the case depth d of the lithium replenishment holes 13a corresponding to the second distribution region 14b is 15 μm, and the case depth d of the lithium replenishment holes 13a corresponding to the first distribution region 14a is 10.5 μm They differ in that they are designed for this purpose.

[0150] Example 5 This embodiment is basically the same as Embodiment 3 described above, but differs in that, at least in the negative electrode plate, the ratio P of the pore area of ​​lithium replenishment holes 13a per unit area is set to 10%, the case depth d of the lithium replenishment holes 13a corresponding to the second distribution region 14b is set to 40 μm, and the case depth d of the lithium replenishment holes 13a corresponding to the first distribution region 14a is set to 31 μm.

[0151] Example 6 This embodiment is basically the same as Embodiment 3 described above, but differs in that, at least in the negative electrode plate, the ratio P of the pore area of ​​lithium replenishment holes 13a per unit area is set to 70%, the case depth d of the lithium replenishment holes 13a corresponding to the second distribution region 14b is set to 7 μm, and the case depth d of the lithium replenishment holes 13a corresponding to the first distribution region 14a is set to 4.5 μm.

[0152] Example 7 This is basically the same as in Example 3 above, but at least the average weight M of the active material per unit area in the first distribution region 14a of the negative electrode edge is different. A 0.0068 g / cm³ 2 , the average weight M of the active material per unit area in the second distribution region 14b of the negative electrode edge A 0.0090 g / cm³ 2 The case depth d of the lithium replenishment hole 13a corresponding to the second distribution region 14b is 5 μmThe case depth d of the lithium replenishment hole 13a corresponding to the first distribution region 14a is 1.0 μm They differ in that they are designed for this purpose.

[0153] Example 8 This is basically the same as in Example 3 above, but at least the average weight M of the active material per unit area in the first distribution region 14a of the negative electrode edge is different. A The average weight of the active material per unit area M is 0.0120 g / cm² in the second distribution region 14b at the negative electrode edge. A 0.0150 g / cm³ 2 They differ in that the case depth d of the lithium replenishment hole 13a corresponding to the second distribution region 14b is designed to be 25 μm, while the case depth d of the lithium replenishment hole 13a corresponding to the first distribution region 14a is designed to be 20.0 μm.

[0154] Example 9 This is basically the same as Comparative Example 4, but at least in the negative electrode plate, the pore area ratio P of lithium replenishment holes 13a per unit area is set to 50%, the case depth d of the lithium replenishment holes 13a corresponding to the second distribution region 14b is set to 8 μm, and the case depth d of the lithium replenishment holes 13a corresponding to the first distribution region 14a is set to 5.0 μm They differ in that they are designed for this purpose.

[0155] Example 10 This is basically the same as Comparative Example 5, but differs in that, at least in the negative electrode plate, the pore area ratio P of lithium replenishment holes 13a per unit area is set to 50%, the case depth d of the lithium replenishment holes 13a corresponding to the second distribution region 14b is set to 7 μm, and the case depth d of the lithium replenishment holes 13a corresponding to the first distribution region 14a is set to 4.0 μm.

[0156] Example 11 This is substantially the same as Comparative Example 6, but differs in that, at least in the negative electrode plate, the pore area ratio P of lithium replenishment holes 13a per unit area is set to 50%, the case depth d of the lithium replenishment holes 13a corresponding to the second distribution region 14b is set to 4.0 μm, and the case depth d of the lithium replenishment holes 13a corresponding to the first distribution region 14a is set to 3.0 μm.

[0157] Some of the parameters for each example and comparative example are shown in Tables 2-1 and 2-2 below.

[0158] Table 2-2 shows the results of the room-temperature cycle performance test of battery 100 manufactured in the above comparative examples and examples.

[0159] [Table 2-1]

[0160] Table 2-2 shows that when comparing Examples 3 to 6 with Comparative Example 2, in the same chemical system, if the pore depth of the lithium replenishment holes 13a satisfies both of the above two inequalities simultaneously, and the depth d differs depending on the thickness of the different distribution regions 14, then an increase in the pore area ratio P of the lithium replenishment holes 13a per unit area does not significantly affect the performance of the positive electrode gram capacity (i.e., the performance of the positive electrode gram capacity reaches its limit and does not improve further), but the number of cycles increases, that is, the cycle life of battery 100 can be improved.

[0161] Comparing Examples 7 and 8 with Comparative Example 3, if the hole depth of the lithium replenishment hole 13a does not simultaneously satisfy the two inequalities above, then the depth d of the lithium replenishment hole 13a is given priority.

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[0162] From Example 9 and Comparative Example 4, Example 10 and Comparative Example 5, and Example 11 and Comparative Example 6, it can be seen that in any of the chemical systems, when the depth d of the lithium replenishment hole 13a satisfies both of the above two inequalities simultaneously, and changes in a positive correlation with the thickness of the negative electrode active layer 12 in the distribution region 14 where the magnitude of the depth d is different, the number of cycles of the battery 100 is clearly improved, and the cycle life of the battery 100 can be effectively improved.

[0163] [Table 2-2] JPEG0007858040000028.jpg109170

[0164] According to some embodiments of this application, the application provides an electrode assembly comprising a positive electrode plate, a negative electrode plate, and a separator placed between the positive electrode plate and the negative electrode plate, where the positive electrode plate and / or the negative electrode plate is the electrode plate 10 in any of the above embodiments.

[0165] According to some embodiments of this application, the present application provides a secondary battery 100 including an electrode assembly of the above-described embodiment.

[0166] According to some embodiments of this application, the present application provides a power consumption device including a secondary battery 100 in the above-described embodiment.

[0167] Through several embodiments of this application, this application provides a longer-life negative electrode and battery 100, enabling quantitative and accurate lithium replenishment, effective control of lithium replenishment amount and poka-yoke, and specific embodiments are as follows: 1. Apply to one side of the negative electrode plate and perform cold pressing. 2. The single-sided negative electrode plate is drilled with holes of different depths in different areas using methods such as laser drilling and roller nail drilling. 3. Metallic lithium is deposited directionally into the holes using methods such as lithium strip rolling or magnetron sputtering. 4. The negative electrode plates described above are stacked or wound in the order of "positive electrode / separator / single-sided negative electrode plate / single-sided negative electrode plate / separator / positive electrode" to assemble the battery 100. In this case, the two single-sided negative electrode plates are assembled by attaching the sides with holes drilled between them to allow for lithium replenishment, and one side of each negative electrode active material faces the separator.

[0168] To achieve precise lithium replenishment control, the design of the hole depths d in different regions of the negative electrode plate must satisfy the following relationship.

[0169]

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[0170] When the pore depth d satisfies the minimum value of Equation 1-1, filling the lithium replenishment pore 13a with metallic lithium enables sufficient expression of the positive electrode gram capacity, which is effective in improving energy density. As the pore depth d increases further, the amount of lithium replenishment increases, and although the expression of the positive electrode gram capacity does not improve further even when it reaches its limit, it is effective in improving the cycle life.

[0171] At the same time, in order to replenish excess lithium and avoid lithium deposition in the negative electrode cycling process, the design of the pore depths d in different regions of the negative electrode plate must satisfy the following relationship:

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[0172] The pore depth d must satisfy both Equation 1-1 and Equation 1-2 simultaneously. If Equation 1-1 and Equation 1-2 cannot be satisfied simultaneously, the pore depth d must preferentially satisfy Equation 1-2 to avoid safety risks due to lithium deposition. Also, the average weight M of the active material per unit area of ​​the negative electrode. A By increasing the value, the hole depth d can be adjusted so that equations 1-1 and 1-2 are simultaneously satisfied.

[0173] Finally, it should be noted that the above embodiments are used solely to illustrate the technical concepts of this application and are not limiting. While this application has been described in detail with reference to the embodiments described herein, as those skilled in the art will understand, it is still possible to modify the technical concepts described in the embodiments described herein, or to substitute some or all of the technical features with equivalents. Such modifications or substitutions should not deviate the essence of the corresponding technical concepts from the scope of the technical concepts of the embodiments of this application and should be included within the scope of the claims and specification of this application. In particular, any technical features mentioned in each embodiment can be combined in any way, provided there is no structural inconsistency. This application is not limited to the specific embodiments disclosed herein, but includes all technical concepts included in the claims.

[0174] 1000, Vehicle; 100, Battery; 200, Controller; 300, Motor; 110, Housing; 111, First Part; 112, Second Part; 120, Battery Cell; 10, Electrode Plate; 11, Current Collector Structure; 11a, Current Collector; 12, Active Layer; 13, Lithium Refill Space; 13a, Lithium Refill Hole; 14, Distribution Area; 14a, First Distribution Area; 14b, Second Distribution Area; 15, Lithium Refill Layer; 16, Single-Sided Electrode Plate.

Claims

1. It is a plate, Current collection structure, The present invention includes two active layers, each provided on opposing side surfaces of the current collector structure in the thickness direction of the current collector structure, and the current collector structure is provided with a plurality of lithium replenishment spaces used to communicate with one of the active layers, and a lithium replenishment agent is contained within the lithium replenishment spaces, The lithium replenishment space is a lithium replenishment hole, In the distribution region on the active layer that is in communication with the lithium replenishment space, the average weight of the active substance per unit area of ​​the active layer is M. Ａ The distribution region is defined as the sum of the volumes in the lithium replenishment space covered by the projection in the thickness direction of the current collection structure, and the distribution region includes at least a first distribution region and a second distribution region. M in the first distribution region Ａ M in the second distribution region Ａ The corresponding V0 in the first distribution region is smaller than the corresponding V0 in the second distribution region, Let d be the depth of the lithium replenishment space, with units of μm, and let h be the thickness of the active layer corresponding to the position where the lithium replenishment space is located. In the first distribution region, h is smaller than h in the second distribution region, and the corresponding d in the first distribution region is smaller than the corresponding d in the second distribution region. The depth d of the lithium replenishment space is [Math 1] The relationship satisfies this condition, C Ａ This is the initial lithium storage capacity of the negative electrode active material mAh / g, and C Ｃ This is the initial lithium release capacity of the positive electrode active material mAh / g, and M Ｃ This is the average weight of the active material per unit area of ​​the positive electrode (g / cm³). ２ P is the ratio of the opening area of ​​all lithium replenishment spaces per unit area on the current collection structure, The depth d of the lithium replenishment space is [Math 2] Furthermore, satisfying this relationship, C.E. Ｃ is the initial Coulomb efficiency of the positive electrode active material, and C.E. Ａ is the initial Coulomb efficiency of the negative electrode active material, and C Ａ is the initial lithium storage capacity mAh / g of the negative electrode active material, the electrode plate.

2. The ratio P of the opening area of ​​all lithium replenishment spaces per unit area is: The electrode plate according to claim 1, satisfying the relationship 10% ≤ P ≤ 50%.

3. The electrode plate according to claim 1 or 2, wherein in at least one of the active layers, the lithium replenishment spaces are spaced apart, and the spacing between any two adjacent lithium replenishment spaces is equal.

4. The electrode plate according to claim 1 or 2, wherein the current collection structure includes at least one current collector in the thickness direction of the current collection structure, and the lithium replenishment space is provided through at least one of the current collectors on which the active layer is installed.

5. The electrode plate according to claim 4, wherein the current collection structure includes two current collectors, the two active layers are each provided on two sides of the two current collectors that are opposite to each other, and the lithium replenishment space is provided through both of the two current collectors.

6. The electrode plate according to claim 5, further comprising at least one lithium replenishment layer located between the two current collectors.

7. The electrode plate according to claim 1 or 2, wherein the lithium replenishment hole extends into the active layer on either side along the thickness direction of the current collection structure.

8. The electrode plate according to claim 1 or 2, wherein the first distribution region is installed extending along the periphery of the second distribution region.

9. A method for manufacturing an electrode plate, Two single-sided plates are provided, and in this case, the single-sided plates include a current collector and an active layer provided on one side of the current collector, step S100, At least one of the single-sided electrode plates has lithium replenishment holes that extend into the active layer relative to the current collector, and the average weight M of the active material per unit area in at least two distribution regions on the active layer Ａ The sum of the volumes inside the lithium replenishment holes V0 in the first distribution region is given by M Ａ M in the second distribution region Ａ The control is performed such that the value is smaller and the corresponding V0 in the first distribution region is smaller than the corresponding V0 in the second distribution region, and here the step S200 includes the distribution region including the first distribution region and the second distribution region, Step S300 involves depositing a lithium replenisher in the lithium replenishment hole, The process includes step S400, which involves bonding the sides of the two single-sided electrode plates that are facing away from the active layer to each other. Step S200 is, Step S210 to obtain the thickness h of the active layer in different distribution regions, Step S220 involves uniformly opening a plurality of lithium replenishment holes in the current collector, Step S230 includes controlling the depth d of the lithium replenishment hole in the projection region on the current collector of each distribution region such that h in the first distribution region is smaller than h in the second distribution region, and d corresponding to the first distribution region is smaller than d corresponding to the second distribution region, wherein the unit of depth d is μm. The depth d of the lithium replenishment hole is [Math 3] The relationship satisfies this condition, Here, C Ａ This is the initial lithium storage capacity of the negative electrode active material mAh / g, and C Ｃ This is the initial lithium release capacity of the positive electrode active material mAh / g, and M Ｃ This is the average weight of the active material per unit area of ​​the positive electrode (g / cm³). ２ Therefore, P is the ratio of the pore area of ​​all lithium replenishment holes per unit area in the current collection structure. The depth d of the lithium replenishment hole is [Math 4] Furthermore, satisfying this relationship, Here, C. E. Ｃ This is the initial Coulomb efficiency of the positive electrode active material, C.E. Ａ This is the initial Coulomb efficiency of the negative electrode active material, C Ａ A method for manufacturing an electrode plate, wherein is the initial lithium storage capacity of the negative electrode active material in mAh / g.

10. An electrode assembly comprising a positive electrode plate, a negative electrode plate, and a separator provided between the positive electrode plate and the negative electrode plate, An electrode assembly wherein the positive electrode plate and / or the negative electrode plate are the electrode plates described in claim 1.

11. A secondary battery comprising the electrode assembly described in claim 10.

12. A power consumption device including a secondary battery as described in claim 11.

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