Battery cell assembly and battery
By setting recessed grooves in the positive and negative electrode active material layers of the battery and optimizing the ratio of depth to base film thickness, the problem of electrolyte wetting difficulty is solved, thereby improving the battery's cycle performance and energy density.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- CALB GROUP CO LTD
- Filing Date
- 2025-08-14
- Publication Date
- 2026-07-03
AI Technical Summary
In high-capacity batteries, difficulty in electrolyte wetting leads to black spots on the electrodes, reducing battery cycle performance and energy density.
By setting recessed grooves in the positive and negative electrode active material layers and optimizing the ratio of recessed groove depth to base film thickness, the electrolyte wetting effect is improved and the stability of the diaphragm assembly is enhanced.
It improves the wetting effect of the electrolyte, enhances the cycle performance and energy density of the battery, and improves the stability of the separator assembly.
Smart Images
Figure CN224458146U_ABST
Abstract
Description
Technical Field
[0001] This application relates to a battery cell assembly and a battery, belonging to the field of new energy battery technology. Background Technology
[0002] A battery is a device that converts chemical energy into electrical energy. It is widely used in daily life, and with the development of the battery industry, the requirements for battery performance are becoming increasingly stringent.
[0003] In conceiving and implementing this application, the applicant discovered at least the following problems: With the increasing demand for high-capacity batteries, the volume of individual batteries is constantly increasing, and the length and width of the electrodes in the battery cells are also increasing accordingly. Simultaneously, to better ensure the energy density of the battery, the electrode substrate is becoming thinner, but the active material layer coated on the substrate is becoming thicker. Therefore, during electrolyte filling, the electrolyte needs to wet the junction between the active material layer of the electrode and the separator. Since electrolyte filling occurs between a sealed and molded space, excessive compaction and thermal pressure can lead to difficulties in electrolyte wetting during the filling process. Consequently, electrodes that are not wetted by the electrolyte will develop black spots during use, reducing the battery's cycle performance.
[0004] The preceding description is intended to provide general background information and does not necessarily constitute prior art. Utility Model Content
[0005] This application provides a cell assembly and a battery that can improve the energy density of the battery while enhancing the wetting effect.
[0006] This application provides a battery cell assembly, which includes:
[0007] A positive electrode sheet includes a positive current collector and a positive active material layer disposed on at least one side of the positive current collector;
[0008] A negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer disposed on at least one side of the negative electrode current collector;
[0009] A separator assembly is located between a positive electrode and a negative electrode. The separator assembly includes a base film layer and ceramic layers disposed on opposite sides of the base film layer.
[0010] Among them, at least one of the positive electrode active material layer and the negative electrode active material layer is provided with a recessed groove, and the groove opening faces the membrane assembly.
[0011] Along the thickness direction of the cell assembly, the recessed groove has a depth H, the base film layer has a thickness D1, and the separator assembly has a thickness D. The depth H, thickness D1, and thickness D satisfy: 6μm≤H*(D1 / D)≤95μm.
[0012] In addition, this application also provides a battery, including a casing and the aforementioned cell assembly;
[0013] The housing has a receiving cavity, in which the battery cell assembly is housed.
[0014] The beneficial effects of this application are: by increasing the recessed grooves, the wetting effect of the electrolyte can be improved; furthermore, by limiting the value of H*(D1 / D), while improving the wetting effect and the cycle performance of the battery, the stability of the separator assembly can be improved, thereby increasing the energy density of the battery. Attached Figure Description
[0015] The above and other objects, features, and advantages of embodiments of this application will become more readily understood through the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of this application will be described by way of example and non-limitation, wherein:
[0016] Figure 1 This is a schematic diagram of the structure of a battery according to an embodiment of this application;
[0017] Figure 2 This is a schematic diagram of a battery explosion according to an embodiment of this application;
[0018] Figure 3 This is a schematic diagram of the structure of another battery according to an embodiment of this application;
[0019] Figure 4 This is a schematic diagram of an explosion of another battery according to an embodiment of this application;
[0020] Figure 5 This is a cross-sectional view of a battery cell assembly according to an embodiment of this application;
[0021] Figure 6 This is a partial cross-sectional view of a battery cell assembly according to an embodiment of this application;
[0022] Figure 7 This is a partial cross-sectional view of another battery cell assembly according to an embodiment of this application;
[0023] Figure 8 This is a schematic diagram of the positive electrode active material layer in the battery cell assembly according to an embodiment of this application;
[0024] Figure 9 This is a schematic diagram of the structure of the positive electrode active material layer in the battery cell assembly according to an embodiment of this application.
[0025] Figure label:
[0026] 100-Battery Cell Assembly;
[0027] 110-Positive electrode plate;
[0028] 111 - Positive current collector;
[0029] 112 - Positive electrode active material layer;
[0030] 120-Negative electrode;
[0031] 121 - Negative electrode current collector;
[0032] 122 - Negative electrode active material layer;
[0033] 130 - Diaphragm assembly;
[0034] 131 - Base film layer;
[0035] 132 - Ceramic layer;
[0036] 133 - Adhesive layer;
[0037] 140 - Recessed groove;
[0038] 141 - First groove;
[0039] 142 - Second groove;
[0040] 150 - Insulating film;
[0041] 200-battery;
[0042] 210 - Casing;
[0043] 220 - Cover plate;
[0044] 230-Pole Column. Detailed Implementation
[0045] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. All other obtained embodiments are within the scope of protection of this application. In the absence of conflict, the following embodiments and features can be combined with each other.
[0046] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0047] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.
[0048] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.
[0049] In conceiving and implementing this application, the applicant discovered at least the following problems: With the increasing demand for high-capacity batteries, the volume of individual batteries is constantly increasing, and the length and width of the electrodes in the battery cells are also increasing accordingly. Simultaneously, to better ensure the energy density of the battery, the electrode substrate is becoming thinner, but the active material layer coated on the substrate is becoming thicker. Therefore, during electrolyte filling, the electrolyte needs to wet the junction between the active material layer of the electrode and the separator. Since electrolyte filling occurs between a sealed and molded space, excessive compaction and thermal pressure can lead to difficulties in electrolyte wetting during the filling process. Consequently, electrodes that are not wetted by the electrolyte will develop black spots during use, reducing the battery's cycle performance.
[0050] The battery cell assembly proposed in this application can improve the wetting effect of the electrolyte by adding recessed grooves; furthermore, by limiting the value of H*(D1 / D), the wetting effect can be improved, the cycle performance of the battery can be improved, and the stability of the separator assembly can be improved, thereby increasing the energy density of the battery.
[0051] The battery cell assembly provided in this application will be described in detail below with reference to specific embodiments.
[0052] Figure 1 This is a schematic diagram of the structure of a battery according to an embodiment of this application. Figure 2This is a schematic diagram of a battery explosion according to an embodiment of this application. Figure 3 This is a schematic diagram of another battery structure according to an embodiment of this application. Figure 4 This is a schematic diagram of an explosion of another battery according to an embodiment of this application.
[0053] like Figures 1 to 4 As shown, this application embodiment provides a battery 200, including a housing 210 and the aforementioned cell assembly 100;
[0054] The housing 210 has a receiving cavity in which the battery cell assembly 100 is housed.
[0055] In some examples, the housing 210 can be a rectangular structure, and the size of the housing 210 can be greater than or equal to the size of the cell assembly 100, so that the housing 210 can support the cell assembly 100.
[0056] It is understandable that the function of the receiving cavity is to house the battery cell assembly 100. It is easy to understand that the receiving cavity is sealed to prevent side reactions from occurring in the internal system of the battery cell assembly 100, which would affect the performance of the battery cell assembly 100.
[0057] For example, the size or shape of the receiving cavity is matched with the size and shape of the battery cell assembly 100. Specifically, it can be adjusted according to the actual situation, and the embodiments of this application do not impose too many limitations here.
[0058] In this embodiment, the battery cell assembly 100 can be configured as a rectangular structure. The battery cell assembly 100 can be located inside the housing 210.
[0059] Understandably, the housing 210 can be used to support the battery cell assembly 100.
[0060] like Figure 2 As shown, the battery cell assembly 100 has a wound core structure, such as... Figure 4 As shown, the battery cell assembly 100 has a stacked core structure.
[0061] The dimensions of the aforementioned housing 210 can be set according to actual needs, and this embodiment of the application does not impose any restrictions on them.
[0062] In addition, it should be noted that the shape of the shell 210 is not limited in this embodiment. For example, the shell 210 can be a regular shape such as a cuboid or a cylinder. Of course, the shell 210 can also be other irregular shapes.
[0063] In some embodiments, the housing 210 protects the battery cell assembly 100 therein. The housing 210 may be composed of two parts joined together for easy installation. The housing 210 may be a metal shell. Specifically, the material of the housing 210 may be stainless steel, which is sturdy and corrosion-resistant. Of course, the housing 210 may also be made of other materials, and this embodiment does not impose any specific limitations on this.
[0064] In some embodiments, the battery 200 further includes a cover plate 220, on which a terminal post 230 is provided. The terminal post 230 is electrically connected to the tab in the cell assembly 100. The main function of the terminal post 230 is to conduct the electrical charge on the cell assembly 100 to the outside of the housing 210 for easy use.
[0065] In some embodiments, the electrode post 230 is generally made of a material with good electrical conductivity, such as copper or aluminum.
[0066] Along the length of the battery 200, there are two terminals 230, which are spaced apart on the housing 210. One terminal 230 is the positive terminal 230, and the other terminal 230 is the negative terminal 230.
[0067] It should be noted that the following describes the specific structure of the battery cell assembly 100.
[0068] Figure 5 This is a cross-sectional view of a battery cell assembly according to an embodiment of this application.
[0069] like Figures 1 to 5 As shown in the figure, this application provides a battery cell assembly 100, comprising:
[0070] The positive electrode 110 includes a positive current collector 111 and a positive active material layer 112 disposed on at least one side of the positive current collector 111;
[0071] The negative electrode 120 includes a negative electrode current collector 121 and a negative electrode active material layer 122 disposed on at least one side of the negative electrode current collector 121;
[0072] The separator assembly 130 is located between the positive electrode 110 and the negative electrode 120. The separator assembly 130 includes a base film layer 131 and ceramic layers 132 disposed on opposite sides of the base film layer 131.
[0073] Among them, at least one of the positive electrode active material layer 112 and the negative electrode active material layer 122 is provided with a recessed groove 140, and the groove opening of the recessed groove 140 faces the membrane assembly 130.
[0074] Along the thickness direction of the cell assembly 100, the recessed groove 140 has a depth H, the base film layer 131 has a thickness D1, and the separator assembly 130 has a thickness D. The depth H, thickness D1, and thickness D satisfy: 6μm≤H*(D1 / D)≤95μm.
[0075] Figure 6 This is a partial cross-sectional view of a battery cell assembly according to an embodiment of this application. Figure 7 This is a partial cross-sectional view of another battery cell assembly according to an embodiment of this application.
[0076] It should be noted that Z represents the thickness direction of the battery cell assembly 100.
[0077] like Figures 1 to 7 As shown, it should be noted that the battery cell assembly 100 is the smallest charging and discharging unit. The battery cell assembly 100 has a positive electrode 110, a negative electrode 120, and a separator assembly 130 disposed between the two, and is formed by winding or stacking. The positive electrode 110 includes a positive current collector 111 and a positive active material layer 112, which can be one or two layers; that is, the positive active material layer 112 is located on one side of the positive current collector 111, or the positive active material layer 112 is located on opposite sides of the positive current collector 111.
[0078] The positive electrode 110 is one of the core components in the battery that carries the positive electrode active material. During charging, metal ions (e.g., lithium ions) are extracted from the crystal lattice of the positive electrode active material layer 112 (oxidation reaction), migrate through the electrolyte, and embed into the negative electrode. During discharging, metal ions (e.g., lithium ions in a lithium battery) are extracted from the negative electrode and embed into the crystal lattice of the positive electrode active material layer 112 (reduction reaction), thus realizing the storage and release of lithium ions.
[0079] Furthermore, the positive electrode sheet 110 generally includes a positive electrode current collector 111 and a positive electrode active material layer 112. The positive electrode active material layer is coated on at least one surface of the positive electrode current collector and includes: a positive electrode active material, a conductive agent, and a binder. The positive electrode active material includes, but is not limited to, at least one of the following materials: lithium phosphate, lithium transition metal oxide and their respective modified compounds, or other conventional materials that can be used as positive electrode active materials in batteries. These positive electrode active materials can be used alone or in combination of two or more.
[0080] The lithium-containing phosphates include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4, also known as LFP), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, and lithium manganese iron phosphate and carbon composites. Lithium transition metal oxides include, but are not limited to, lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, and lithium nickel cobalt manganese oxides (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3O2 (Also known as NCM333), LiNi 0.5 Co 0.2 Mn 0.3O2 (Also known as NCM523), LiNi 0.5 Co 0.25 Mn 0.25O2 (Also known as NCM211), LiNi 0.6 Co 0.2 Mn 0.2O2 (Also known as NCM622), LiNi 0.8 Co 0.1 Mn 0.1O2 (Also known as NCM811), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05O2 At least one of the following: ) and its modified compounds.
[0081] The positive electrode conductive agent includes, but is not limited to, one or more combinations of graphite, superconducting carbon, carbon black (such as acetylene black, Ketjen black, Super P, etc.), carbon nanotubes, graphene and carbon nanofibers.
[0082] The positive electrode binder includes, but is not limited to, one or more combinations of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, fluorinated acrylate resin, styrene-butadiene rubber, polyacrylic acid, sodium polyacrylate, polyacrylamide, polyvinyl alcohol, sodium alginate, polymethacrylic acid, carboxymethyl chitosan, etc.
[0083] For example, the positive current collector 111 can be made of metal materials such as aluminum foil, nickel foil, and stainless steel, or a composite foil formed by combining metal and insulating materials.
[0084] During battery charging, active ions (such as Li) from the positive electrode are embedded in the negative electrode, while electrons from the positive electrode are transferred to the negative electrode 120 through the external circuit to maintain charge balance; during discharge, active ions (such as Li) previously embedded in the negative electrode 120 can be released, while electrons from the negative electrode 120 are transferred to the negative electrode through the external circuit to maintain charge balance; thus realizing energy storage and release.
[0085] Exemplarily, the negative electrode 120 includes a negative electrode current collector 121 and a negative electrode active material layer 122 disposed on at least one surface of the negative electrode current collector 121. The negative electrode current collector 121 is a conductive metal foil, which can be made of stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium with a silver-plated surface. The negative electrode current collector 121 may include a polymer material base layer and a metal layer. The negative electrode current collector 121 can be formed by forming a metal material (aluminum, aluminum alloy, copper, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.). The negative electrode active material layer 122 includes a negative electrode active material, a conductive agent, a binder, etc.
[0086] The negative electrode active material can be carbon-based materials such as graphite, porous carbon, hard carbon, soft carbon, and mesophase carbon microspheres, or silicon-based materials such as elemental silicon, silicon oxides, silicon-carbon composites, and silicon-nitrogen composites. The conductive agent can be conductive carbon black, carbon nanotubes, etc., and the binder can be styrene-butadiene rubber, polyacrylic acid, etc.
[0087] Similarly, the negative electrode active material layer 122 can be one or two layers; that is, the negative electrode active material layer 122 is located on one side of the negative electrode current collector 121, or the negative electrode active material layer 122 is located on opposite sides of the negative electrode current collector 121.
[0088] For example, the negative electrode current collector 121 can be made of metal materials such as copper foil, aluminum foil, and stainless steel, or it can be a composite foil material formed by combining metal and insulating materials.
[0089] For example, the negative electrode active material layer 122 includes a negative electrode active material, a conductive agent, a binder, etc., and the negative electrode active material includes one or more of the following: artificial graphite, natural graphite, silicon carbide, silicon oxide, lithium titanate, etc.
[0090] The tab serves as the current output terminal of the battery cell. The tab and the positive electrode 110 or the negative electrode 120 are connected as one piece or separately.
[0091] The separator assembly 130 serves as an insulating layer to prevent short circuits inside the battery cell 200 caused by contact between the positive and negative electrode plates. The separator assembly 130 also serves as a semi-permeable layer to prevent larger molecules from passing through while allowing smaller charged ions to pass through.
[0092] The separator can be at least one of glass fiber, nonwoven fabric, polyethylene (PE), polypropylene (PP), and polyvinylidene fluoride. A coating can also be applied to the separator surface. The coating can be an inorganic coating and, or an organic coating, wherein the inorganic coating material includes at least one of alumina, silicon oxide, titanium oxide, magnesium oxide, zirconium oxide, and boehmite; and the organic coating includes at least one of aramid coating and PVDF coating. It should be noted that the separator assembly 130 includes a base membrane layer 131 and ceramic layers 132 disposed on opposite sides of the base membrane layer 131. The ceramic layers 132 can provide additional thermal stability when the battery 200 overheats, preventing the separator assembly 130 from shrinking or melting, thereby reducing the risk of short circuits and improving the safety of the battery 200. In other words, the ceramic layers 132, with their extremely high thermal stability, can effectively prevent the separator assembly 130 from shrinking or melting under thermal runaway conditions, while also giving it better rigidity and shrinkage resistance.
[0093] It should be noted that the base film layer 131 has multiple microporous structures, which provide a large number of pore spaces, allowing the electrolyte to penetrate and distribute more effectively in the base film layer 131. This helps to increase the contact area between the electrode and the electrolyte, thereby enhancing ion conductivity. This means that ions can move more freely inside the battery 200, which helps to improve the charging and discharging efficiency and overall performance of the battery 200.
[0094] The electrolyte is a liquid electrolyte that transports active ions. It is a liquid material that conducts ions while isolating electrons.
[0095] For example, the electrolyte is composed of chemical substances such as solvents, electrolyte salts, and additives; the solvent may be carbonates, carboxylic acid esters, or ethers; the electrolyte salt may be lithium salts, sodium salts, or zinc salts; and the additives may be vinylene carbonate, fluoroethylene carbonate, propylene sulfite, vinyl sulfite, etc.
[0096] In some embodiments, the diaphragm assembly 130 further includes an adhesive layer 133 located between the base film layer 131 and the ceramic layer 132, that is, the ceramic layer 132 is fixed to the base film layer 131 by the adhesive layer 133.
[0097] In addition, in order to improve the wetting effect of the electrolyte, a recessed groove 140 is provided on at least one of the positive electrode active material layer 112 and the negative electrode active material layer 122, and the recessed groove 140 has a depth H.
[0098] The analysis is as follows: The greater the depth H, the easier it is for the recessed groove 140 to absorb electrolyte and achieve a better wetting effect. Although an excessively large depth H improves the wetting effect, it will reduce the total amount of active material, resulting in a decrease in energy density; while an excessively small depth H may lead to insufficient wetting, affecting the performance of the battery 200.
[0099] Therefore, an appropriate groove depth H of 140 can effectively absorb electrolyte, enhance the contact area between the electrode and the electrolyte, improve the wetting effect of the electrolyte, and thus improve ion conductivity and the overall performance of the battery 200.
[0100] In some embodiments, the recessed groove 140 can be a circular groove, an elliptical groove, or a rectangular groove; no further restrictions are imposed here.
[0101] It should be noted that the larger the D1 / D ratio, the thicker the base film layer 131, and the better the micropores in the base film layer 131 absorb the electrolyte. However, this will result in the ceramic layer 132 being too thin, and the rigidity and shrinkage resistance of the diaphragm assembly 130 being poor.
[0102] Furthermore, it is necessary to select an appropriate value for H*(D1 / D). If it is too large, the stability of the separator module 130 will deteriorate and the energy density of the battery 200 will decrease; if it is too small, the wetting effect will be poor.
[0103] Specifically, excessively large values may lead to an overly thick base film layer 131 or an overly deep groove 140, weakening the thickness of the ceramic layer 132 and thus reducing the thermal stability and mechanical strength of the separator assembly 130; it may also lead to a reduction in active material, thereby reducing the energy density of the battery 200. Insufficiently small values may lead to insufficient electrolyte wetting, affecting the overall performance of the battery 200.
[0104] By adding the recessed groove 140, the wetting effect of the electrolyte can be improved. Furthermore, by limiting the value of H*(D1 / D), the stability of the separator assembly 130 can be improved while improving the wetting effect and the cycle performance of the battery 200, thereby increasing the energy density of the battery 200.
[0105] In some embodiments, an insulating film 150 is provided on the outside of the cell assembly 100.
[0106] For example, the insulating film 150 may consist of a nylon layer, an aluminum foil layer, a heat-sealing layer, and an adhesive for bonding. The innermost heat-sealing layer may be made of polypropylene, which serves as a sealing and bonding agent. Polypropylene has good heat-sealing adhesion to metals Ni and Al, as well as electrode tabs, and possesses resistance to electrolytes, insulation, and puncture resistance. The middle layer may be made of aluminum foil, specifically pure aluminum or an aluminum-iron alloy, which can react with oxygen in the air at room temperature to form an oxide film, preventing oxygen and moisture from penetrating and thus protecting the internal battery cell assembly 100. The outermost layer may be made of nylon, which has good impact resistance, puncture resistance, heat resistance, insulation, and abrasion resistance. It is used to protect the aluminum foil layer from scratches and to reduce the impact and vibration caused to the battery 200 by drops, thereby protecting the internal components.
[0107] In some alternative embodiments, the recess 140 includes a first groove 141 and a second groove 142;
[0108] The first groove 141 is disposed on the positive electrode active material layer 112, and the second groove 142 is disposed on the negative electrode active material layer 122.
[0109] It should be noted that by setting grooves in both the positive and negative electrode active material layers 122, the electrolyte can be uniformly distributed on the electrode surface, reducing the ion transport path and thus improving the ion conduction efficiency and the charge and discharge performance of the battery 200.
[0110] Although the presence of grooves may reduce the total volume of active materials, by optimizing the design of the grooves, other performance indicators of the battery 200 can be improved without significantly reducing energy density.
[0111] In some alternative embodiments, the first groove 141 has a depth H1, which satisfies: 10μm≤H1≤95μm;
[0112] The positive electrode active material layer 112 has a depth H3, and the depths H1 and H3 satisfy: 0.3≤H1 / H3≤0.95.
[0113] It should be noted that an appropriate H1 value ensures that the first groove 141 has sufficient depth to enhance the wetting effect of the electrolyte, thereby improving ion conductivity. By controlling the upper and lower limits of H1, a balance can be achieved between increasing the electrolyte contact area and maintaining structural integrity.
[0114] A suitable range of H1 / H3 ensures that the groove is not too deep, which would significantly reduce the total volume of the positive electrode active material and thus affect the energy density of battery 200. By optimizing the H1 / H3 ratio, the cycle life of battery 200 can be extended while improving the electrolyte wetting effect.
[0115] For example, the depth H1 can be 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, 95μm or any of these values.
[0116] In some alternative embodiments, the second groove 142 has a depth H2, which satisfies: 10μm≤H2≤100μm;
[0117] The negative electrode active material layer 122 has a depth H4, and the depths H2 and H4 satisfy: 0.3≤H2 / H4≤0.99.
[0118] It should be noted that an appropriate H2 value ensures that the second groove 142 has sufficient depth to enhance the wetting effect of the electrolyte, thereby improving ion conductivity. By controlling the upper and lower limits of H2, a balance can be achieved between increasing the electrolyte contact area and maintaining structural integrity.
[0119] For example, the depth H2 can be 10μm, 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm, 100μm or any of these values.
[0120] A suitable H2 / H4 ratio ensures that the groove is not too deep, which would significantly reduce the total volume of the negative electrode active material and thus affect the energy density of battery 200. By optimizing the H2 / H4 ratio, the cycle life of battery 200 can be extended while improving the electrolyte wetting effect.
[0121] In some alternative implementations, the thickness D1 and the thickness D satisfy: 0.7 ≤ D1 / D ≤ 0.95.
[0122] In some embodiments, the thickness D1 satisfies: 3μm≤D1≤30μm.
[0123] For example, the thickness D1 can be 3μm, 5μm, 7μm, 10μm, 13μm, 15μm, 17μm, 20μm, 23μm, 25μm, 30μm or any of these values.
[0124] In some embodiments, the thickness D satisfies: 4μm≤D1≤34μm.
[0125] For example, the thickness D1 can be 4μm, 5μm, 7μm, 10μm, 13μm, 15μm, 17μm, 20μm, 23μm, 25μm, 30μm, 34μm or any of these values.
[0126] It should be noted that a larger D1 / D ratio means a thicker base film layer 131, which enhances the absorption capacity of the electrolyte by the microporous structure of the base film layer 131, improves the electrolyte wetting effect, and thus improves the ion conductivity and overall performance of the battery 200. While a thicker base film layer 131 facilitates electrolyte absorption, if the ceramic layer 132 is too thin, it may weaken the thermal stability and rigidity of the separator assembly 130. The thermal stability of the ceramic layer 132 is crucial to preventing the separator assembly 130 from shrinking and melting under thermal runaway conditions; therefore, an appropriate balance needs to be found between the thickness of the base film layer 131 and the ceramic layer 132.
[0127] By rationally designing the D1 / D ratio, an optimal balance can be achieved between the electrolyte absorption capacity and the thermal stability and mechanical properties of the separator assembly 130, ensuring the performance and safety of the battery 200 under different operating conditions.
[0128] In some alternative embodiments, there are multiple first grooves 141 and second grooves 142;
[0129] Multiple first grooves 141 are respectively spaced along the length and width directions of the cell assembly 100, and multiple second grooves 142 are respectively spaced along the length and width directions of the cell assembly 100.
[0130] It should be noted that the first groove 141 and the second groove 142, which are spaced apart, allow the electrolyte to penetrate quickly and the ions to conduct rapidly, reducing the ion transport path and allowing ions to move more quickly between the electrodes, thereby improving the charging and discharging efficiency.
[0131] In some embodiments, the number of the first groove 141 and the second groove 142 is not limited here.
[0132] Figure 8 This is a schematic diagram of the positive electrode active material layer in the battery cell assembly according to an embodiment of this application. Figure 9 This is a schematic diagram of the structure of the positive electrode active material layer in the battery cell assembly according to an embodiment of this application.
[0133] like Figures 5 to 9 As shown, in some optional embodiments, along the length direction of the cell assembly 100, there is a spacing L1 between two adjacent first grooves 141 and a spacing L2 between two adjacent second grooves 142.
[0134] Along the width direction of the cell assembly 100, there is a spacing L3 between two adjacent first grooves 141 and a spacing L4 between two adjacent second grooves 142;
[0135] Among them, the spacing L1 and spacing L3 located in the middle of the cell assembly 100 are less than or equal to the spacing L1 and spacing L3 located at the edge of the cell assembly 100;
[0136] The spacing L2 and spacing L4 located in the middle of the cell assembly 100 are less than or equal to the spacing L2 and spacing L4 located at the edge of the cell assembly 100.
[0137] It should be noted that X represents the length direction of the battery cell assembly 100, and Y represents the width direction of the battery cell assembly 100.
[0138] It should be noted that setting smaller spacing (L1, L3, L2, L4) in the middle of the cell assembly 100 can increase the groove density in the central region, thereby enhancing the electrolyte wetting effect. This helps to provide a more uniform electrolyte distribution in the key areas of the cell and improve ion conductivity.
[0139] Since wetting in the middle is more difficult, the high-density design of the first groove 141 and the second groove 142 in the middle region helps to accelerate the penetration of electrolyte and ion conduction, enabling the battery 200 to support higher charge and discharge rates, making it suitable for fast-response application scenarios.
[0140] Furthermore, by increasing the groove density in the central region while maintaining a larger spacing in the edge region, other performance indicators of the battery 200 can be improved without significantly reducing the energy density.
[0141] In some embodiments, the specific values of L1, L3, L2, and L4 are not limited here.
[0142] In some alternative embodiments, the slot size of the first groove 141 located in the middle of the cell assembly 100 is larger than the slot size of the first groove 141 located at the edge of the cell assembly 100; and / or,
[0143] The groove size of the second groove 142 located in the middle of the cell assembly 100 is larger than the groove size of the second groove 142 located at the edge of the cell assembly 100.
[0144] It should be noted that the first groove 141 and the second groove 142 in the central region have a large opening size, which can increase the penetration and contact area of the electrolyte, thereby improving the wetting effect of the electrolyte. This helps to reduce the obstruction of the ion transport path, allowing ions to move more quickly between the electrodes and improving the charging and discharging efficiency.
[0145] The larger slot size helps accelerate electrolyte penetration and ion conduction, enabling the battery 200 to support high-rate charge and discharge, making it suitable for fast-response applications. Although the larger slot size may reduce the total volume of active materials, with proper design, other performance indicators of the battery 200 can be improved without significantly reducing energy density.
[0146] In some alternative embodiments, the depth of the first groove 141 located in the middle of the cell assembly 100 is greater than the depth of the first groove 141 located at the edge of the cell assembly 100; and / or,
[0147] The depth of the second groove 142 located in the middle of the cell assembly 100 is greater than the depth of the second groove 142 located at the edge of the cell assembly 100.
[0148] It should be noted that the first groove 141 and the second groove 142 in the central region have a considerable depth, which can increase the penetration capacity of the electrolyte and thus improve the wetting effect of the electrolyte. This helps to provide more efficient ion conductivity in the key areas of the cell.
[0149] Deeper grooves help reduce obstruction to ion transport paths, allowing ions to move more quickly between electrodes and improving charge and discharge efficiency.
[0150] The battery cell assembly provided in this application includes: a positive electrode sheet, including a positive current collector and a positive active material layer disposed on at least one side of the positive current collector; a negative electrode sheet, including a negative current collector and a negative active material layer disposed on at least one side of the negative current collector; and a separator assembly located between the positive electrode sheet and the negative electrode sheet, the separator assembly including a base film layer and ceramic layers disposed on opposite sides of the base film layer; wherein, at least one of the positive active material layer and the negative active material layer is provided with a recessed groove, the groove opening facing the separator assembly; along the thickness direction of the battery cell assembly, the recessed groove has a depth H, the base film layer has a thickness D1, and the separator assembly has a thickness D, the depth H, the thickness D1, and the thickness D satisfy: 6μm≤H*(D1 / D)≤95μm.
[0151] By adding recessed grooves, the wetting effect of the electrolyte can be improved; further, by limiting the value of H*(D1 / D), the wetting effect and cycle performance of the battery can be improved, while the stability of the separator assembly can be improved, thereby increasing the energy density of the battery.
[0152] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.
[0153] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.
[0154] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.
Claims
1. A battery cell assembly (100), characterized in that, include: A positive electrode sheet (110) includes a positive current collector (111) and a positive active material layer (112) disposed on at least one side of the positive current collector (111); The negative electrode sheet (120) includes a negative electrode current collector (121) and a negative electrode active material layer (122) disposed on at least one side of the negative electrode current collector (121); A separator assembly (130) is located between the positive electrode (110) and the negative electrode (120). The separator assembly (130) includes a base film layer (131) and ceramic layers (132) disposed on opposite sides of the base film layer (131). The positive electrode active material layer (112) and the negative electrode active material layer (122) are provided with a recessed groove (140), and the groove opening of the recessed groove (140) faces the membrane assembly (130). Along the thickness direction of the cell assembly (100), the recessed groove (140) has a depth H, the base film layer (131) has a thickness D1, and the separator assembly (130) has a thickness D. The depth H, the thickness D1, and the thickness D satisfy: 6μm≤H*(D1 / D)≤95μm.
2. The electric cell assembly (100) according to claim 1, characterized in that The recessed groove (140) includes a first groove (141) and a second groove (142); The first groove (141) is disposed on the positive electrode active material layer (112), and the second groove (142) is disposed on the negative electrode active material layer (122).
3. The electric cell assembly (100) of claim 2, characterized in that The first groove (141) has a depth H1, which satisfies: 10μm≤H1≤95μm; The positive electrode active material layer (112) has a depth H3, and the depths H1 and H3 satisfy: 0.3≤H1 / H3≤0.
95.
4. The electric cell assembly (100) of claim 2, wherein, The second groove (142) has a depth H2, which satisfies: 10μm≤H2≤100μm; The negative electrode active material layer (122) has a depth H4, and the depths H2 and H4 satisfy: 0.3≤H2 / H4≤0.
99.
5. The cell assembly (100) according to any one of claims 1 to 4, characterized in that The thickness D1 and the thickness D satisfy: 0.7≤D1 / D≤0.
95.
6. The cell assembly (100) according to any one of claims 2-4, characterized in that, Both the first groove (141) and the second groove (142) are multiple; A plurality of first grooves (141) are respectively spaced along the length and width directions of the battery cell assembly (100), and a plurality of second grooves (142) are respectively spaced along the length and width directions of the battery cell assembly (100).
7. The electric cell assembly (100) of claim 6, characterized in that Along the length direction of the cell assembly (100), there is a spacing L1 between two adjacent first grooves (141) and a spacing L2 between two adjacent second grooves (142); Along the width direction of the cell assembly (100), there is a spacing L3 between two adjacent first grooves (141) and a spacing L4 between two adjacent second grooves (142); Wherein, the spacing L1 and the spacing L3 located in the middle of the battery cell assembly (100) are less than or equal to the spacing L1 and the spacing L3 located at the edge of the battery cell assembly (100); The spacing L2 and the spacing L4 located in the middle of the cell assembly (100) are less than or equal to the spacing L2 and the spacing L4 located at the edge of the cell assembly (100).
8. The cell assembly (100) according to claim 6, characterized in that, The slot size of the first groove (141) located in the middle of the cell assembly (100) is larger than the slot size of the first groove (141) located at the edge of the cell assembly (100); and / or, The groove size of the second groove (142) located in the middle of the cell assembly (100) is larger than the groove size of the second groove (142) located at the edge of the cell assembly (100).
9. The cell assembly (100) according to any one of claims 2-4, characterized in that, The depth of the first groove (141) located in the middle of the cell assembly (100) is greater than the depth of the first groove (141) located at the edge of the cell assembly (100); and / or, The depth of the second groove (142) located in the middle of the cell assembly (100) is greater than the depth of the second groove (142) located at the edge of the cell assembly (100).
10. A battery (200) characterized by, Includes a housing (210) and a cell assembly (100) as described in any one of claims 1 to 9; The housing (210) has a receiving cavity in which the cell assembly (100) is received.