Negative pole piece, battery and electric equipment
The introduction of a porous scaffold-based rich liquid medium in the negative electrode layer addresses electrolyte depletion in secondary batteries, maintaining electrolyte levels and enhancing lithium ion engagement to prolong battery life.
Patent Information
- Application Number
- CN202422232644.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-11
- Publication Date
- 2025-07-15
- Estimated Expiration
- 2034-09-11
AI Technical Summary
During the use of the secondary battery, the expansion of the electrode sheet causes the electrolyte to be unable to be completely wet, resulting in lithium extraction, which leads to a faster capacity attenuation and shorter service life.
The negative electrode active material layer of the negative electrode sheet is introduced into the liquid-rich medium, including a porous three-dimensional framework and conductive agent, for storing and releasing the electrolyte, replenishing the electrolyte in the battery, and extending the battery life.
By introducing a liquid-rich medium into the negative electrode sheet, the electrolyte consumption rate is slowed down, the charging and discharging performance of the battery is extended, and the service life of the battery is improved.
Smart Images
Figure CN223108897U_ABST
Abstract
Description
Technical Field
[0001] The embodiments of the present application relate to the technical field of energy storage devices, and in particular, to a negative electrode plate, a battery, and an electrical device. Background Art
[0002] During the charge and discharge processes of a secondary battery, both electrolyte and electrode plates are involved. Therefore, the degree of complete wetting of the electrode plates by the electrolyte in the secondary battery is an important factor affecting the cycle life of the electrode plates and also affects the service life of the entire secondary battery. As the usage time of the secondary battery increases, the electrode plates will inevitably expand, which will inevitably lead to a reduction in the distance between the electrode plates. Furthermore, during the operation of the secondary battery, the electrolyte cannot completely wet the electrode plates, and finally, lithium deposition occurs due to insufficient electrolyte in the electrode plates, resulting in an accelerated capacity decay rate and a sharp shortening of the service life of the entire secondary battery during continuous cycling. Summary of the Utility Model
[0003] In view of the above problems, the embodiments of the present application provide a negative electrode plate, a battery, and an electrical device, which can supplement the electrolyte to slow down the capacity decay rate of the battery and extend the service life of the battery.
[0004] According to the first aspect of the embodiments of the present application, a negative electrode plate is provided. The negative electrode plate includes a negative electrode current collector and a negative electrode active material layer. The negative electrode active material layer is disposed on both side surfaces of the negative electrode current collector. The negative electrode active material layer includes a liquid-rich medium. The liquid-rich medium includes a porous three-dimensional framework and a conductive agent, and the conductive agent is filled in the pores of the three-dimensional framework.
[0005] By adopting the above solution, the negative electrode active material layer is disposed on both side surfaces of the negative electrode current collector and is used for lithium ions to shuttle and embed during the charge and discharge processes of the battery. The negative electrode active material layer includes a liquid-rich medium. When the battery expands during charging, the liquid-rich medium in the negative electrode active material layer is squeezed, causing the liquid-rich medium to release a certain amount of electrolyte, thereby supplementing the electrolyte in the housing of the battery cell and slowing down the consumption rate of the electrolyte. The liquid-rich medium includes a three-dimensional framework and a conductive agent. The three-dimensional framework has a porous property, so it can accommodate more electrolyte. Moreover, the pores of the three-dimensional framework can not only accommodate electrolyte but also accommodate solid liquid storage particles, such as a conductive agent. The conductive agent is filled in the pores of the three-dimensional framework and absorbs a large amount of electrolyte. During the use of the battery, the electrolyte is gradually released under extrusion. The electrolyte consumption rate in the battery using the above electrode assembly is slower, and the capacity decay is slower. Therefore, the battery can maintain good charge and discharge performance for a long time and extend the service life of the battery.
[0006] In some embodiments, the negative electrode active material layer includes a first negative electrode active material layer and a second negative electrode active material layer. The second negative electrode active material layer is disposed on a side of the first negative electrode active material layer away from the negative electrode current collector, and the average particle size of the material of the second negative electrode active material layer is smaller than the average particle size of the material of the first negative electrode active material layer.
[0007] By adopting the above solution, since the average particle size of the material of the second negative electrode active material layer is smaller than the average particle size of the material of the first negative electrode active material layer, the gaps between the materials of the second negative electrode active material layer are more than the gaps between the materials of the first negative electrode active material layer. Thus, the kinetics of the second negative electrode active material layer is higher than that of the first negative electrode active material layer. The second negative electrode active material layer can accommodate more electrolyte, and lithium ions are more likely to be embedded in the negative electrode plate. That is to say, during the charge and discharge process, more lithium ions will participate in the chemical reaction, reducing the precipitation of lithium ions on the surface of the negative electrode plate and slowing down the consumption rate of lithium ions on the negative electrode plate, thereby slowing down the capacity attenuation rate of the battery and extending the service life of the battery.
[0008] In some embodiments, the rich liquid medium is disposed within the second negative electrode active material layer and / or within the first negative electrode active material layer.
[0009] By adopting the above solution, the rich liquid medium can be within the second negative electrode active material layer or the first active material layer, enabling lithium ions to directly embed into the negative electrode plate through the electrolyte in the rich liquid medium. When the rich liquid medium is squeezed, it can release the electrolyte and infiltrate the first negative electrode active material or the second negative electrode active material around the rich liquid medium, enabling the first negative electrode active material layer and the second negative electrode active material layer to have sufficient lithium ion channels for lithium ions to be embedded, thereby slowing down the capacity attenuation rate of the battery.
[0010] In some embodiments, the rich liquid medium is disposed between the second negative electrode active material layer and the first negative electrode active material layer.
[0011] By adopting the above solution, the rich liquid medium is conducive to the passage of lithium ions, thus facilitating the entry of lithium ions from the second negative electrode active material layer into the first negative electrode active material layer and increasing the embedding depth of lithium ions in the negative electrode plate. When the rich liquid medium is squeezed, the electrolyte in the rich liquid medium can directly infiltrate the first negative electrode active material layer and the second negative electrode active material layer, enabling the first negative electrode active material layer and the second negative electrode active material layer to remain moist for a long time, further facilitating the improvement of the charge and discharge performance of the battery, slowing down the capacity attenuation rate of the battery and extending the service life of the battery.
[0012] In some embodiments, the rich liquid medium is disposed between the first negative electrode active material layer and the negative electrode current collector.
[0013] By adopting the above - mentioned solution, the position between the first negative electrode active material layer and the negative electrode current collector is the position farthest from the surface of the negative electrode plate. It is not easy to be infiltrated by the electrolyte here. By setting the liquid - rich medium here, the electrolyte retention amount here can be increased, so that the first negative electrode active material layer can be kept in a state of being infiltrated by the electrolyte for a long time, which is beneficial to the insertion of lithium ions into the first negative electrode active material layer, improves the charge - discharge performance of the battery, and prolongs the service life of the battery.
[0014] In some embodiments, the three - dimensional framework is an alumina framework.
[0015] By adopting the above - mentioned solution, the alumina framework can generally naturally form spherical porous particles, which have high mechanical strength, strong liquid absorption capacity, can expand after absorbing liquid, and will shrink again after the electrolyte is released. This is contrary to the change law of the electrode plate during the use of the battery (the electrode plate will expand more severely in the later stage of cycling, and the liquid storage medium will shrink as the electrode plate expands, releasing space for the electrode plate particles), thereby reducing the deformation pressure generated by the expansion of the electrode plate on the battery monomer housing in the later stage of battery use. The alumina framework also has the property of being insoluble in water and organic substances. As the carrier for storing the electrolyte and carrying the conductive agent, it can absorb and store more electrolytes without changing the performance and size of the electrode assembly, and gradually release them during the use of the battery to reduce the capacity attenuation rate of the battery and prolong the service life of the battery.
[0016] In some embodiments, the conductive agent is conductive carbon black.
[0017] By adopting the above - mentioned solution, conductive carbon black has very good liquid absorption capacity, can store more electrolytes, and increase the supplement amount of the electrolyte.
[0018] In some embodiments, the liquid - rich medium is in the shape of spherical particles.
[0019] By adopting the above - mentioned solution, the spherical - particle - shaped liquid - rich medium can be stressed in any direction and release the electrolyte, without stress concentration and the situation of being stressed only on a specific surface.
[0020] According to the second aspect of the embodiments of the present application, a battery is provided, including the negative electrode plate in any of the above - mentioned embodiments.
[0021] According to the third aspect of the embodiments of the present application, an electrical device is provided, including the battery in any of the above - mentioned embodiments.
[0022] The batteries and electrical devices in the embodiments of the above - mentioned second aspect and third aspect both include the electrode assembly in the above - mentioned first theme. Therefore, the batteries and electrical devices have the respective structures and beneficial effects of the above - mentioned electrode assembly. For the specific structure description and beneficial effects, please refer to the structure descriptions and beneficial effects in the embodiments of the electrode assembly. The related structures of the batteries and electrical devices in the embodiments of the present application will not be elaborated herein.
[0023] In the embodiment of the present application, a liquid-rich medium is provided in the negative active material layer of the electrode assembly. When the battery expands during charging, the liquid-rich medium in the negative active material layer is squeezed, causing the liquid-rich medium to release a certain amount of electrolyte, thereby supplementing the electrolyte in the battery cell casing and slowing down the consumption rate of the electrolyte. The liquid-rich medium includes a three-dimensional framework and a conductive agent, both of which can absorb and store the electrolyte and gradually release the electrolyte when squeezed during the use of the battery. The electrolyte in the battery using the above electrode assembly has a slower consumption rate and a slower capacity decay, so that the battery can maintain good charge and discharge performance for a long time and extend the service life of the battery.
[0024] The above description is only an overview of the technical solution of the embodiment of the present application. In order to be able to understand the technical means of the embodiment of the present application more clearly, it can be implemented according to the content of the description. And in order to make the above and other purposes, features and advantages of the embodiment of the present application more obvious and understandable, the following specifically describes the specific implementation manners of the present application. Description of the Drawings
[0025] In order to more clearly illustrate the technical solution of the embodiment of the present application, the drawings required for the description of the embodiment will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.
[0026] Figure 1 Schematic structural diagram of the first negative electrode plate in an embodiment of the present application.
[0027] Figure 2 Schematic microstructural diagram of a liquid-rich medium in an embodiment of the present application.
[0028] Figure 3 Schematic structural diagram of the second negative electrode plate in an embodiment of the present application.
[0029] Figure 4 Schematic structural diagram of the third negative electrode plate in an embodiment of the present application.
[0030] Figure 5 Schematic structural diagram of the fourth negative electrode plate in an embodiment of the present application.
[0031] Description of the reference numerals: 100, negative current collector; 200, negative active material layer; 210, first negative active material layer; 220, second negative active material layer; 300, liquid-rich medium; 310, three-dimensional framework; 320, conductive agent. Detailed Description of the Invention
[0032] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the following will clearly and completely describe the technical solutions in the embodiments of this application with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, rather than all of them. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within 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 of ordinary skill in the technical field to which this application belongs; the terms used in the description of this application in the specification are only for the purpose of describing specific embodiments and are not intended to limit this application.
[0034] The terms "including" and "having" and any variations thereof in the description, claims, and drawings of this application are intended to cover but not exclude other elements. The word "a" or "an" does not exclude the presence of multiple ones.
[0035] Referring to "embodiments" herein means that the specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of this application. The phrase "embodiments" appearing at various positions in the specification does not necessarily refer to the same embodiment, nor are they independent or alternative embodiments mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.
[0036] The term "and / or" herein is merely a description of the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. Additionally, the character " / " herein generally represents an "or" relationship between the associated objects before and after.
[0037] The orientation terms appearing in the following description are all the directions shown in the figures and do not specifically limit the structure of the negative electrode plate, battery, or electrical device of this application. For example, in the description of this application, terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to this application.
[0038] In addition, terms such as "first", "second", etc. in the description and claims of this application or in the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order, and may explicitly or implicitly include one or more of such features.
[0039] In the description of this application, unless otherwise specified, the meaning of "a plurality" refers to two or more (including two). Similarly, "a plurality of groups" refers to two or more groups (including two groups).
[0040] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, "connected" or "coupled" of a mechanical structure may refer to a physical connection. For example, a physical connection may be a fixed connection, such as a fixed connection through a fixing member, such as a fixed connection through screws, bolts, or other fixing members; a physical connection may also be a detachable connection, such as a snap connection or a snap-fit connection; a physical connection may also be an integral connection, such as a connection formed by welding, bonding, or integral molding. "Connected" or "coupled" of a circuit structure may refer to not only a physical connection but also an electrical connection or a signal connection. For example, it may be a direct connection, that is, a physical connection, or may be indirectly connected through at least one intermediate element, as long as the circuit is connected; it may also be the internal connection of two elements; a signal connection may refer to not only a signal connection through a circuit but also a signal connection through a media medium, such as radio waves. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.
[0041] During the use of a battery, the electrolyte is a continuously consumed substance, and the electrolyte is an essential medium for the transfer of lithium ions during the charge and discharge process of the battery. Therefore, the amount of the electrolyte seriously affects the capacity and service life of the battery.
[0042] In view of the above problems, the embodiments of this application provide a negative electrode plate, a battery, and an electrical device, which absorb a relatively large amount of electrolyte and can continuously release the electrolyte during the use of the battery, so as to supplement the electrolyte, thereby slowing down the capacity attenuation rate of the battery and extending the service life of the battery.
[0043] The above battery includes the above electrode assembly, and the above electrical device includes the above battery and can be powered by the above battery. Among them, the above electrical device can be a vehicle, mobile phone, portable device, laptop computer, ship, spacecraft, electric toy, power tool, energy storage device, amusement device, elevator, lifting device, etc. The vehicle can be a fuel vehicle, gas vehicle or new energy vehicle. The new energy vehicle can be a pure electric vehicle, hybrid vehicle or range-extended vehicle, etc.; the spacecraft includes airplanes, rockets, space shuttles, spaceships, etc.; the electric toy includes stationary or mobile electric toys, for example, game consoles, electric vehicle toys, electric ship toys or electric airplane toys, etc.; the power tool includes metal cutting power tools, grinding power tools, assembly power tools and railway power tools, for example, electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact electric drills, concrete vibrators and electric planers, etc.; the energy storage device can be an energy storage wall, base station energy storage, container energy storage, etc.; the amusement device can be a carousel, drop tower, etc. This application does not impose special restrictions on the above electrical device.
[0044] For new energy vehicles, the above battery can be used as a drive power source to replace fossil fuels and provide driving power.
[0045] The above battery can be a battery cell, battery pack or battery module. When the above battery is a battery pack, the battery pack specifically includes a Battery Management System (BMS) and multiple above battery cells. The multiple battery cells can be electrically connected in series, parallel or a combination of series and parallel, and communicate with the battery management system to form a battery pack. The above battery management system controls and monitors the working states of the individual battery cells. In addition, multiple battery cells can also be first connected in series and / or parallel and form a battery module with a module management system, and then multiple battery modules are electrically connected in series, parallel or a combination of series and parallel, and jointly constitute a battery pack with the battery management system.
[0046] Among them, the multiple battery cells in the above battery pack or battery module can be installed on support structures such as boxes, frames, brackets, etc. The individual battery cells and between the battery cells and the battery management system can be electrically connected through busbar components such as busbars. The above battery cells can be lithium-ion batteries, sodium-ion batteries or magnesium-ion batteries, and their external profiles can be cylindrical, flat, cuboid or other shapes, but are not limited thereto.
[0047] Generally, a battery cell includes a battery case and an electrode assembly, and the electrode assembly is accommodated in the battery case. The electrode assembly is the smallest unit in the battery where electrochemical reactions occur, enabling the charge and discharge of the battery cell. It typically includes a positive electrode plate, a negative electrode plate, and a separator that separates the positive electrode plate and the negative electrode plate. An electrolyte is injected into the battery case, and the electrolyte can infiltrate into the interior of the electrode assembly, providing an ion migration path for the electrochemical reaction of the electrode assembly and acting as a conductor.
[0048] Figure 1 FIG. 4 is a schematic structural view of the first negative electrode plate in an embodiment of the present application. Figure 2 FIG. 6 is a schematic microstructural view of a rich-liquid medium in an embodiment of the present application.
[0049] Please refer to Figure 1 and Figure 2 , the negative electrode plate provided by the embodiment of the present application includes a negative electrode current collector 100 and a negative electrode active material layer 200. The negative electrode active material layer 200 is disposed on both side surfaces of the negative electrode current collector 100. The negative electrode active material layer 200 includes a rich-liquid medium 300. The rich-liquid medium 300 includes a porous three-dimensional framework 310 and a conductive agent 320, and the conductive agent 320 is filled in the pores of the three-dimensional framework 310.
[0050] The negative electrode active material layer 200 is disposed on both side surfaces of the negative electrode current collector 100, and is used for lithium ions to shuttle and embed during the charge and discharge process of the battery.
[0051] The negative electrode current collector 100 is generally a structure or component for collecting current. The negative electrode current collector 100 can be various materials in the art suitable for use as the negative electrode current collector 100 of a lithium-ion battery. For example, the negative electrode current collector 100 can include, but is not limited to, metal foils, etc., and more specifically can include, but is not limited to, copper foils or carbon-coated copper foils, etc.
[0052] The material of the negative electrode active material layer 200 can include, but is not limited to, one or several of graphite, soft carbon, hard carbon, carbon fiber, mesophase carbon microspheres, silicon-based materials, tin-based materials, lithium titanate, or other metals that can form alloys with lithium. The embodiment of the present application also does not make any limitations thereto.
[0053] The negative electrode active material layer 200 includes a rich-liquid medium 300. As one of the components in the negative electrode active material layer 200, the rich-liquid medium 300 can be mixed with other components in the negative electrode active material and then coated on the surface of the negative electrode current collector 100, or can be coated on the surface of the negative electrode current collector 100 alone, or can be coated alone in the middle of the negative electrode active material layer 200.
[0054] The rich liquid medium 300 is a substance rich in electrolyte, with a liquid absorption capacity and an electrolyte storage capacity higher than ordinary substances, and does not affect the normal electrical cycling reaction of the battery cell. After using the rich liquid medium 300, the rich liquid medium 300 can store a certain amount of electrolyte, making the total amount of electrolyte in the battery in the initial state higher than that of existing batteries. When the battery expands during charging, the rich liquid medium 300 in the negative active material layer 200 is squeezed, causing the rich liquid medium 300 to release a certain amount of electrolyte, thereby supplementing the electrolyte in the housing of the battery cell and slowing down the consumption rate of the electrolyte.
[0055] Please refer to Figure 2 , the rich liquid medium 300 includes a three-dimensional framework 310 and a conductive agent 320. The three-dimensional framework 310 has a porous property, enabling it to accommodate more electrolyte. Moreover, the pores of the three-dimensional framework 310 can not only accommodate electrolyte but also solid liquid storage particles, such as the conductive agent 320. The conductive agent 320 is filled in the pores of the three-dimensional framework 310, absorbing a large amount of electrolyte and gradually releasing the electrolyte when being squeezed during the use of the battery.
[0056] Therefore, the electrolyte consumption rate in the battery using the above electrode assembly is slower, and the capacity decay is slower. As a result, the battery can maintain good charge and discharge performance for a long time, extending the service life of the battery.
[0057] The following gives examples of possible materials and structures of the rich liquid medium 300.
[0058] In some embodiments, the rich liquid medium 300 is in the shape of spherical particles.
[0059] By adopting the above solution, the spherical particle-shaped rich liquid medium 300 can be deformed under force in any direction and release electrolyte, without stress concentration and the situation of only being stressed on a specific surface.
[0060] It can be understood that the spherical particle shape is only the approximate shape of the rich liquid medium 300. During actual manufacturing, the rich liquid medium 300 is not a regular spherical shape. It can be an ellipsoidal shape or have a certain convex or concave structure on its surface.
[0061] In some embodiments, the material of the three-dimensional framework 310 includes at least one of carbon materials, aluminum, copper, titanium, iron, nickel, and compounds containing the above metal elements.
[0062] In a specific implementation, when the material of the three-dimensional framework 310 is a carbon material, the three-dimensional framework 310 can include, but is not limited to, carbon cloth and carbon fiber cloth.
[0063] In another specific embodiment, when the material of the three-dimensional framework 310 is a metal material such as aluminum, copper, titanium, iron or nickel, the three-dimensional framework 310 can be copper foam, titanium foam, iron foam or nickel foam, etc.
[0064] In some embodiments, when the material of the three-dimensional framework 310 is a compound containing metal elements such as aluminum, copper, titanium, iron or nickel, the three-dimensional framework 310 can be aluminum oxide.
[0065] The above three-dimensional framework 310 has good electrical conductivity and high mechanical strength, and can provide a stable space for lithium metal to deposit in the pores of the three-dimensional framework 310. Selecting the three-dimensional framework 310 within the above range can provide a good conductive channel, which is beneficial to the current during uniform charge and discharge, form a more uniform electric field, improve the uniformity and density of lithium metal deposition, and thus improve the cycle performance of the battery while storing and releasing the electrolyte.
[0066] Among them, in the materials of the above three-dimensional frameworks 310, the alumina framework generally can be naturally formed into spherical porous particles, which have high mechanical strength and strong liquid absorption capacity. After absorbing the liquid, it can expand, and will shrink again after the electrolyte is released, which is opposite to the change law of the electrode plate during the use of the battery (the electrode plate will expand more severely in the later stage of cycling, and the liquid storage medium will shrink as the electrode plate expands, releasing space for the electrode plate particles), thereby reducing the deformation pressure generated by the expansion of the electrode plate on the battery cell housing in the later stage of battery use. The alumina framework also has the characteristics of being insoluble in water and organic substances. As a carrier for storing the electrolyte and carrying the conductive agent, it can absorb and store more electrolyte without changing the performance and size of the electrode assembly, and gradually release it during the use of the battery to reduce the capacity attenuation rate of the battery and extend the service life of the battery.
[0067] In some embodiments, the conductive agent 320 is any one of Ketjen black, acetylene black, conductive carbon black, graphene, and carbon nanotubes.
[0068] In a specific embodiment, when the conductive agent 320 is conductive carbon black, it can be Super.P carbon black. Super.P carbon black has an extremely high specific surface area and conductivity, and has a high capacity, rate performance and cycle stability for the absorption of lithium / sodium ions. The capacity of Super.P carbon black to store lithium ions is as high as 310 mAhg -1 , while storing the electrolyte, it is beneficial to the storage and shuttling of lithium ions in the rich liquid medium 300.
[0069] Taking the three-dimensional framework 310 as alumina and the conductive agent 320 as Super.P carbon black as an example, the forming process of the rich liquid medium 300 can be:
[0070] The first step is to form an alumina skeleton, which is a hollow granular structure with an outer diameter of about 1-30 μm (micrometer).
[0071] The second step is to immerse the alumina skeleton in glue, which may be PVDF (polyvinylidene fluoride) glue, and the concentration of the glue is 0.05%-20%.
[0072] The third step is to blow Super.P carbon black into the alumina skeleton through air flow, and wrap carbon nanotubes around the outer circle to form a liquid storage island.
[0073] After the rich liquid medium 300 is formed through the above process, the rich liquid medium 300 is mixed in the negative electrode active material, or is coated on the negative electrode active material layer 200 alone, so as to be added to the negative electrode plate.
[0074] The negative electrode active material layer 200 can also be arranged in various ways.
[0075] like Figure 3 , Figure 4 and Figure 5 As shown, in some embodiments, the negative electrode active material layer 200 includes a first negative electrode active material layer 210 and a second negative electrode active material layer 220, the second negative electrode active material layer 220 is arranged on the side of the first negative electrode active material layer 210 away from the negative electrode current collector 100, and the average particle size of the material of the second negative electrode active material layer 220 is smaller than the average particle size of the material of the first negative electrode active material layer 210.
[0076] The material of the first negative electrode active material layer 210 and the material of the second negative electrode active material layer 220 may be the same or different. In the present application, the maximum particle size of the material of the first negative electrode active material layer 210 and the maximum particle size of the material of the second negative electrode active material layer 220 can be controlled to achieve the purpose of controlling the average particle size of the material of the second negative electrode active material layer 220 to be smaller than the average particle size of the material of the first negative electrode active material layer 210. For example, the maximum particle size of the material of the second negative electrode active material layer 220 can be controlled to be 80 μm (micrometers) by screening, and the maximum particle size of the material of the first negative electrode active material layer 210 can be controlled to be 100 μm. The embodiment of the present application does not specify the control and measurement method of the average particle size of the material of the first negative electrode active material layer 210 and the average particle size of the material of the second negative electrode active material layer 220.
[0077] Since the average particle size of the material of the second negative electrode active material layer 220 is smaller than that of the material of the first negative electrode active material layer 210, there are more gaps between the materials of the second negative electrode active material layer 220 than between the materials of the first negative electrode active material layer 210. Thus, the kinetics of the second negative electrode active material layer 220 is higher than that of the first negative electrode active material layer 210, the second negative electrode active material layer 220 can accommodate a larger amount of electrolyte, and lithium ions are more likely to be embedded in the negative electrode plate. That is to say, during the charge and discharge process, more lithium ions will participate in the chemical reaction, reducing the precipitation of lithium ions on the surface of the negative electrode plate and slowing down the consumption rate of lithium ions on the negative electrode plate, thereby slowing down the capacity attenuation rate of the battery and prolonging the service life of the battery.
[0078] According to the structure of the negative electrode active material layer 200 described above, the rich liquid medium 300 can exist in the following forms.
[0079] Please refer to Figure 3 , in some embodiments, the rich liquid medium 300 is disposed in the second negative electrode active material layer 220 and / or the first negative electrode active material layer 210.
[0080] The rich liquid medium 300 can be separately disposed in the first negative electrode active material layer 210, or separately disposed in the second negative electrode active material layer 220, or the rich liquid medium 300 can be disposed in both the first negative electrode active material layer 210 and the second negative electrode active material layer 220. Figure 3 Taking the case where the rich liquid medium 300 is disposed in both the first negative electrode active material layer 210 and the second negative electrode active material layer 220 as an example for illustration.
[0081] The specific setting manner of the rich liquid medium 300 in the second negative electrode active material layer 220 and / or the first negative electrode active material layer 210 can be: mixing the rich liquid medium 300 in the first negative electrode active material or the second negative electrode active material, and spraying it onto the negative electrode current collector 100 together with the first negative electrode active material or the second negative electrode active material, thereby forming the above structure.
[0082] By adopting the above solution, the rich liquid medium 300 can enable lithium ions to be directly embedded in the negative electrode plate through the electrolyte in the rich liquid medium 300 in the second negative electrode active material layer 220 or the first active material layer. The rich liquid medium 300 can also release the electrolyte when being squeezed and infiltrate the first negative electrode active material or the second negative electrode active material around the rich liquid medium 300, so that the first negative electrode active material layer 210 and the second negative electrode active material layer 220 have sufficient lithium ion channels for lithium ions to be embedded, thereby slowing down the capacity attenuation rate of the battery and prolonging the service life of the battery.
[0083] Such as Figure 4As shown, in some embodiments, the rich liquid medium 300 is disposed between the second negative electrode active material layer 220 and the first negative electrode active material layer 210.
[0084] Specifically, the implementation method can be that after the first negative electrode active material is coated, a layer of solid rich liquid medium particles is sprayed on the surface of the first negative electrode active material layer 210, and then the second negative electrode active material is coated. After the negative electrode plate is installed in the battery case and the electrolyte is injected into the case, the solid rich liquid medium particles absorb the electrolyte and expand to form a rich liquid medium layer, and the electrolyte is retained in the rich liquid medium 300.
[0085] The rich liquid medium 300 is conducive to the passage of lithium ions, so that it is conducive to the entry of lithium ions from the second negative electrode active material layer 220 into the first negative electrode active material layer 210, which is conducive to increasing the embedding depth of lithium ions in the negative electrode plate. When the rich liquid medium 300 is squeezed, the electrolyte in the rich liquid medium 300 can directly infiltrate the first negative electrode active material layer 210 and the second negative electrode active material layer 220, so that the first negative electrode active material layer 210 and the second negative electrode active material layer 220 remain in a wet state for a long time, which is further conducive to improving the charge and discharge performance of the battery, slowing down the capacity attenuation rate of the battery and extending the service life of the battery.
[0086] As Figure 5 shown, in some embodiments, the rich liquid medium 300 is disposed between the first negative electrode active material layer 210 and the negative electrode current collector 100.
[0087] Specifically, the implementation method can be that before the first negative electrode active material is coated on the negative electrode current collector 100, a layer of solid rich liquid medium particles is sprayed on the surface of the negative electrode current collector 100, and then the first negative electrode active material and the second negative electrode active material are coated. After the negative electrode plate is installed in the battery case and the electrolyte is injected into the case, the solid rich liquid medium particles absorb the electrolyte and expand to form a rich liquid medium layer, and the electrolyte is retained in the rich liquid medium 300.
[0088] The position between the first negative electrode active material layer 210 and the negative electrode current collector 100 is the position farthest from the surface of the negative electrode plate, where it is not easy to be infiltrated by the electrolyte. Setting the rich liquid medium 300 here can increase the electrolyte retention amount here, so that the first negative electrode active material layer 210 remains in a state of being infiltrated by the electrolyte for a long time, which is conducive to the embedding of lithium ions into the first negative electrode active material layer 210, improves the charge and discharge performance of the battery, and extends the service life of the battery.
[0089] In summary, in the embodiment of the present application, a liquid-rich medium 300 is provided in the negative electrode active material layer 200 of the electrode assembly. When the battery expands during charging, the liquid-rich medium 300 in the negative electrode active material layer 200 is squeezed, causing the liquid-rich medium 300 to release a certain amount of electrolyte, thereby supplementing the electrolyte in the housing of the battery cell and slowing down the consumption rate of the electrolyte. The liquid-rich medium 300 includes a three-dimensional framework 310 and a conductive agent 320. Both the three-dimensional framework 310 and the conductive agent 320 can absorb and store the electrolyte, and gradually release the electrolyte when being squeezed during the use of the battery. The electrolyte in the battery using the above electrode assembly has a slower consumption rate and a slower capacity decay, so that the battery can maintain good charge and discharge performance for a long time and extend the service life of the battery.
[0090] The battery provided by the embodiment of the present application includes the negative electrode tab in any of the above embodiments.
[0091] The electrical equipment provided by the embodiment of the present application includes the battery in the above embodiment.
[0092] The above battery and electrical equipment both include the above electrode assembly. Therefore, the battery and the electrical equipment have the respective structures and beneficial effects of the above electrode assembly. For the specific structure description and beneficial effects, please refer to the embodiments of the electrode assembly. The embodiments of the present application will not repeat the relevant structures of the battery and the electrical equipment.
[0093] Those skilled in the art can understand that although some embodiments herein include certain features included in other embodiments rather than other features, the combination of the features of different embodiments means that it is within the scope of the present application and forms different embodiments. For example, in the claims, any of the claimed embodiments can be used in any combination.
[0094] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.
Claims
1. A negative electrode plate, characterized in that, It includes a negative electrode current collector and a negative electrode active material layer. The negative electrode active material layer is disposed on both side surfaces of the negative electrode current collector. The negative electrode active material layer includes a liquid-rich medium, and the liquid-rich medium includes a porous three-dimensional framework and a conductive agent, and the conductive agent is filled in the pores of the three-dimensional framework.
2. The negative electrode sheet according to claim 1, wherein The negative electrode active material layer includes a first negative electrode active material layer and a second negative electrode active material layer. The second negative electrode active material layer is disposed on a side of the first negative electrode active material layer away from the negative electrode current collector, and the average particle size of the material of the second negative electrode active material layer is smaller than the average particle size of the material of the first negative electrode active material layer.
3. The negative electrode sheet according to claim 2, wherein The liquid-rich medium is disposed in and / or within the second negative electrode active material layer and the first negative electrode active material layer.
4. The negative electrode sheet according to claim 2, characterized in that, The liquid-rich medium is disposed between the second negative electrode active material layer and the first negative electrode active material layer.
5. The negative electrode sheet according to claim 2, characterized in that, The liquid-rich medium is disposed between the first negative electrode active material layer and the negative electrode current collector.
6. The negative electrode sheet according to claim 1, wherein, The three-dimensional framework is an alumina framework.
7. The negative electrode sheet according to claim 1, characterized in that, The conductive agent is conductive carbon black.
8. The negative electrode sheet according to claim 1, wherein, The liquid-rich medium is in the shape of spherical particles.
9. A battery, characterized in that, It includes the negative electrode tab according to any one of claims 1-8.
10. An electrical device, characterized in that, It includes the battery according to claim 9.