Battery monomer, battery and electric device
By increasing the roughness of the active layer of the electrode sheet and forming grooves on its surface, the problem of poor bonding performance between the electrode sheet and the separator is solved, and the bonding performance and safety of the battery cell are improved.
Patent Information
- Application Number
- CN202421485812.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-26
- Publication Date
- 2025-07-08
- Estimated Expiration
- 2034-06-26
AI Technical Summary
The poor bonding performance between the electrode sheet and the separator in the battery cell causes wrinkles to occur, affecting battery performance and safety.
By increasing the roughness of the active layer of the electrode sheet, it is bonded to the diaphragm, increasing mechanical coupling, and forming grooves by roll molding or spray molding process to improve the bonding performance.
Enhance the adhesion between the electrode sheet and the diaphragm, reduce the risk of the electrode sheet wrinkle, and improve the performance and safety of the battery cell.
Smart Images
Figure CN223079132U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of batteries, and in particular, to a battery cell, a battery, and an electrical device. Background Art
[0002] Batteries are increasingly widely used in life and production. For example, new energy vehicles equipped with batteries have been widely used, and batteries can be used to provide power for all or part of new energy vehicles.
[0003] In the related art, the battery cells of batteries have pole pieces and separators that are adhesively bonded to each other. The adhesion performance between the pole pieces and the separators is poor, which easily causes the pole pieces to wrinkle, resulting in a decline in the performance of the battery and a reduction in safety. Summary of the Utility Model
[0004] In view of this, embodiments of the present application are expected to provide a battery cell, a battery, and an electrical device that can improve the adhesion performance between the pole piece and the separator.
[0005] In order to achieve the above object, the technical solution of the embodiments of the present application is realized as follows:
[0006] The first aspect of the embodiments of the present application provides a battery cell, including an electrode assembly, and the electrode assembly includes:
[0007] A pole piece, including a current collector and an active layer, where the active layer is disposed on at least one surface of the current collector in the thickness direction, and the roughness of the active layer is 1.5 μm to 30 μm;
[0008] A separator, located on the side of the active layer away from the current collector in the thickness direction and adhesively bonded to the active layer.
[0009] For the battery cell provided by the embodiments of the present application, the roughness of the active layer is relatively high. By increasing the roughness of the active layer, the mechanical coupling effect between the pole piece and the separator is increased, and the adhesion force between the active layer and the separator is increased, so as to improve the adhesion performance between the pole piece and the separator and reduce the risk of the pole piece wrinkling caused by full charge of the electrode assembly and other situations.
[0010] In some embodiments, the active layer is formed with grooves.
[0011] In this embodiment, the grooves can not only increase the roughness of the active layer, but also improve the wetting effect of the electrolyte and improve the performance of the battery cell.
[0012] In some embodiments, the grooves are roll-formed structures.
[0013] In this embodiment, the grooves are formed by a roll-forming process, which has a simple process, good controllability, and low cost.
[0014] In some embodiments, taking the plane perpendicular to the thickness direction of the current collector as the projection plane, the projected shape of the groove is dot-shaped or linear.
[0015] In this embodiment, the wetting effect of the electrode sheet is improved by grooves with different projected shapes.
[0016] In some embodiments, the active layers are provided on both surfaces of the current collector along the thickness direction; taking the plane perpendicular to the thickness direction of the current collector as the projection plane, the projections of the grooves of the two active layers are misaligned.
[0017] In this embodiment, the projections of the grooves of the two active layers do not overlap. Designed in this way, it is avoided that the overlapping of the grooves of the two active layers causes local overpressure of the electrode sheet.
[0018] In some embodiments, the depth of the groove along the thickness direction is 0.5 μm to 5 μm.
[0019] In this embodiment, the depth of the groove along the thickness direction is appropriate, matching the thickness dimension of the active layer, being easy to roll and form, and also being able to reduce the risk of the groove affecting the current collector.
[0020] In some embodiments, the active layer is a spray-formed structure.
[0021] In this embodiment, the active layer is formed by the spray-forming process, and the roughness of the active layer can be adjusted by controlling the particle size and surface density of the particles, and the process is simple.
[0022] In some embodiments, the active layer includes a middle region and an edge region, the edge region surrounds the outer periphery of the middle region, and the roughness of the middle region is greater than the roughness of the edge region.
[0023] In this embodiment, during the cycling of the battery cell, the central position of the electrode sheet is more likely to expand and deform, and the degree of deformation is also greater closer to the central position, which is easy to separate from the separator and cause wrinkles; therefore, the roughness of the middle region is greater than the roughness of the edge region to strengthen the bonding performance between the middle region and the separator.
[0024] In some embodiments, the roughness of the middle region is 5 μm to 30 μm; and / or,
[0025] the roughness of the edge region is 1.5 μm to 15 μm.
[0026] In this embodiment, the roughness of the middle region is appropriate and easy to manufacture and form. The roughness of the edge region is appropriate and easy to manufacture and form.
[0027] In some embodiments, the electrode is a positive electrode, the current collector is a positive current collector, the active layer is a positive active layer, and the roughness of the positive active layer is 1.5 μm to 15 μm.
[0028] In this embodiment, the roughness of the positive active layer is moderate, which is adapted to the thickness of the positive active layer, and the manufacturing difficulty is relatively low, making it easy to form.
[0029] In some embodiments, the electrode is a negative electrode, the current collector is a negative current collector, the active layer is a negative active layer, and the roughness of the negative active layer is 5 μm to 30 μm.
[0030] In this embodiment, the roughness of the negative active layer is moderate, which is adapted to the thickness of the negative active layer, and the manufacturing difficulty is relatively low, making it easy to form.
[0031] In the second aspect of the embodiments of the present application, a battery is provided, including the battery cell described above.
[0032] The battery provided by the embodiments of the present application includes the battery cell of the present application and has the same or corresponding beneficial effects as the battery cell.
[0033] In the third aspect of the embodiments of the present application, an electrical device is provided, including the battery described above for providing electrical energy.
[0034] The electrical device provided by the embodiments of the present application includes the battery cell of the present application and has the same or corresponding beneficial effects as the battery cell. Description of the Drawings
[0035] Figure 1 It is a schematic structural diagram of a vehicle in an embodiment of the present application;
[0036] Figure 2 It is an exploded schematic diagram of a battery cell in an embodiment of the present application;
[0037] Figure 3 It is a schematic structural diagram of a first type of electrode in an embodiment of the present application;
[0038] Figure 4 It is a schematic structural diagram of a second type of electrode in an embodiment of the present application;
[0039] Figure 5 It is a schematic structural diagram of a third type of electrode in an embodiment of the present application;
[0040] Figure 6 It is a schematic structural diagram of an electrode assembly in an embodiment of the present application.
[0041] Description of the Reference Numerals
[0042] Vehicle 1000; battery 100; controller 200; motor 300;
[0043] Battery cell 1; electrode assembly 11; electrode tab 111; positive electrode tab 111a; negative electrode tab 111b; active layer 1111; groove 1111a; separator 112; housing 12; shell 121; end cap 122. Detailed implementation mode
[0044] The embodiments of the technical solutions of the present application will be described in detail below with reference to the accompanying drawings. The following embodiments are only used to illustrate the technical solutions of the present application more clearly, so they are only examples and cannot be used to limit the protection scope of the present application.
[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application.
[0046] Referring to "embodiment" herein means that the specific features, structures or characteristics described in connection with the embodiment may be included in at least one embodiment of this application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein may be combined with other embodiments.
[0047] It should be noted that in this application, at least two includes two and more than two. A plurality includes two and more than two. The unit "mg / mm 2 " is milligrams per square millimeter. The unit "μm" is micrometer.
[0048] In the related art, the bonding performance between the electrode tab and the separator is poor. During the continuous charge and discharge cycle of the battery cell, a gap is generated between the electrode tab and the separator, the electrode tab is prone to wrinkles, the cycle life of the battery cell decreases, and the safety is reduced.
[0049] The embodiments of the present application provide a battery cell. The battery cell includes an electrode assembly. The electrode assembly includes an electrode tab and a separator. The electrode tab includes a current collector and an active layer. The active layer is provided on at least one surface of the current collector in the thickness direction. The roughness of the active layer is 1.5 μm to 30 μm. The separator is located on the side of the active layer away from the current collector in the thickness direction and is bonded to the active layer.
[0050] The battery cell provided by the embodiment of the present application has a relatively high roughness of the active layer. By increasing the roughness of the active layer, the mechanical coupling effect between the electrode sheet and the separator is enhanced, and the adhesion between the active layer and the separator is increased, so as to improve the adhesion performance between the electrode sheet and the separator and reduce the risk of the electrode sheet wrinkling caused by full charge of the electrode assembly and other situations.
[0051] Please refer to Figure 1 and Figure 2 , the embodiment of the present application provides a battery 100, and the battery 100 includes the battery cell 1 in any one of the embodiments of the present application.
[0052] In some embodiments, the battery 100 includes a box body, and the battery cell 1 is located inside the box body. The box body can protect the battery cell 1 to prevent liquids or other foreign objects from affecting the charge and discharge of the battery cell 1.
[0053] Exemplarily, the box body can be a sealed box body, thus having more reliable dust and water protection performance, so it can be applied to scenarios with more severe, humid, or even immersion use environments.
[0054] The battery cell 1 provided by the embodiment of the present application can be a secondary battery, and a secondary battery refers to a battery cell that can be activated by charging after discharging and can be used continuously.
[0055] Exemplarily, at least two battery cells 1 in the battery 100 can be connected in series, parallel, or in a hybrid connection. A hybrid connection means that there are both series and parallel connections among at least two battery cells 1. At least two battery cells 1 can be directly connected in series, parallel, or in a hybrid connection together; of course, it can also be that at least two battery cells 1 are first connected in series, parallel, or in a hybrid connection to form a module form, and then the modules are connected in series, parallel, or in a hybrid connection to form a whole.
[0056] The battery 100 can also include other structures. For example, the battery 100 can also include a busbar component for realizing the electrical connection between at least two battery cells 1.
[0057] Please refer to Figure 1 , the embodiment of the present application also provides an electrical device, and the electrical device includes the battery 100 in any one of the embodiments of the present application for providing electrical energy.
[0058] The electrical device includes but is not limited to energy storage devices, mobile phones, tablets, laptop computers, electric toys, power tools, battery cars, electric vehicles, ships, or spacecraft, etc. Among them, electric toys can include fixed or mobile electric toys. For example, game consoles, electric vehicle toys, electric ship toys, and electric aircraft toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spaceships, etc.
[0059] In the following embodiments, for convenience of description, the electrical device in an embodiment of the present application is taken as an example of a vehicle 1000 for illustration. The following will be described with reference to the accompanying drawings.
[0060] Figure 1 The structural schematic diagram of the vehicle 1000 provided by some embodiments of the present application. The vehicle 1000 can be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. As Figure 1 shown, a battery 100 is provided inside the vehicle 1000, and the battery 100 can be provided at the bottom of the vehicle 1000 or at the front or rear of the vehicle 1000. The battery 100 can be used for power supply of the vehicle 1000. For example, the battery 100 can be used as the operating power source of the vehicle 1000. The vehicle 1000 can also include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to supply power to the motor 300. For example, it is used for the working power requirements during the start, navigation and driving of the vehicle 1000.
[0061] In some embodiments of the present application, the battery 100 can not only be used as the operating power source of the vehicle 1000, but also as the driving power source of the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.
[0062] Please refer to Figures 2 to 6 , the battery cell 1 provided by the embodiment of the present application. The battery cell 1 includes an electrode assembly 11, and the electrode assembly 11 includes a current collector and an active layer 1111. The current collector is provided with the active layer 1111 on at least one surface in the thickness direction. The roughness of the active layer 1111 is 1.5 μm to 30 μm. The separator 112 is located on the side away from the current collector in the thickness direction of the active layer 1111 and is bonded to the active layer 1111.
[0063] The electrode assembly 11 is the energy storage structure of the battery cell 1.
[0064] The separator 112 can be arranged between two current collectors 111, and the polarities of the current collectors 111 on both sides of the separator 112 in the thickness direction are opposite. The separator 112 can play a role in preventing short circuit.
[0065] Exemplarily, the current collector has two surfaces opposite to each other in its own thickness direction, and the active layer 1111 is provided on either or both of the two surfaces opposite to each other in the thickness direction of the current collector. In one embodiment, the active layer 1111 is provided on one surface in the thickness direction of the current collector. In another embodiment, the active layer 1111 is provided on both surfaces in the thickness direction of the current collector.
[0066] The roughness of the active layer 1111 ranges from 1.5 μm to 30 μm. Exemplarily, the roughness of the active layer 1111 is 1.5 μm, 5 μm, 6.6 μm, 7 μm, 8 μm, 10 μm, 12.5 μm, 15 μm, 20 μm, 25 μm, 30 μm, etc.
[0067] The separator 112 is bonded to the active layer 1111, which can reduce the relative movement between the separator 112 and the electrode tab 111.
[0068] For the battery cell 1 provided by the embodiment of the present application, the roughness of the active layer 1111 is relatively high. By increasing the roughness of the active layer 1111, the mechanical coupling effect between the electrode tab 111 and the separator 112 is increased, and the adhesion between the active layer 1111 and the separator 112 is increased, so as to improve the bonding performance between the electrode tab 111 and the separator 112, and reduce the risk of wrinkles generated on the electrode tab 111 caused by full charge of the electrode assembly 11 and other conditions.
[0069] It can be understood that the roughness of the active layer 1111 refers to the unevenness of the surface of the active layer 1111 along the thickness direction away from the current collector. The roughness of the active layer 1111 can be used to characterize the surface micro-morphology of the active layer 1111, and the roughness can be measured by the test methods well-known in the art.
[0070] It should be noted that in the embodiment of the present application, the thickness directions of the current collector, the active layer 1111, and the separator 112 are the same.
[0071] In one embodiment, the electrode tab 111 is a positive electrode tab 111a or a negative electrode tab 111b.
[0072] In one embodiment, please refer to Figures 3 to 6 , the electrode tab 111 is a positive electrode tab 111a, the current collector is a positive current collector, the active layer 1111 is a positive active layer, and the roughness of the positive active layer ranges from 1.5 μm to 15 μm. Exemplarily, the roughness of the positive active layer is 1.5 μm, 2 μm, 5 μm, 8 μm, 10 μm, 13 μm, 15 μm, etc. With such a design, the roughness of the positive active layer is moderate, adapted to the thickness of the positive active layer, and the manufacturing difficulty is relatively low, and it is easy to form.
[0073] In one embodiment, please refer to Figures 3 to 6 , the electrode tab 111 is a negative electrode tab 111b, the current collector is a negative current collector, the active layer 1111 is a negative active layer, and the roughness of the negative active layer ranges from 5 μm to 30 μm. Exemplarily, the roughness of the negative active layer is 5 μm, 7 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, etc. With such a design, the roughness of the negative active layer is moderate, adapted to the thickness of the negative active layer, and the manufacturing difficulty is relatively low, and it is easy to form.
[0074] In one embodiment, please refer to Figures 3 to 5 , a groove 1111a is formed in the active layer 1111. The groove 1111a can not only increase the roughness of the active layer 1111, but also improve the wetting effect of the electrolyte, thereby enhancing the performance of the battery cell 1.
[0075] In one embodiment, please refer to Figures 3 to 5 , the groove 1111a is a roll-formed structure. In other words, the groove 1111a is formed by pressing a pressure roller against the active layer 1111. The groove 1111a is formed by using a roll-forming process, which has the advantages of simple process, good controllability, and low cost.
[0076] In one embodiment, the circumferential surface of the pressure roller has protrusions, and the protrusions press against the active layer 1111 to form the groove 1111a. For example, during the cold pressing process of the electrode sheet 111, the pressure roller rotates, and the pressure roller with protrusions rolls on the active layer 1111 of the electrode sheet 111, and the protrusions roll on the active layer 1111 to form the groove 1111a.
[0077] In one embodiment, please refer to Figures 3 to 5 , taking the plane perpendicular to the thickness direction of the current collector as the projection plane, the projected shape of the groove 1111a is dot-shaped or linear. The dot shape can be circular (please refer to Figure 5 ), oval, polygonal, or irregular, etc. The linear shape can be a continuously extending straight line (please refer to Figure 3 and Figure 4 ) or a curve, etc. For example, the projected shape of the groove 1111a is spiral-shaped. By using grooves 1111a with different projected shapes, the wetting effect of the electrode sheet 111 is improved.
[0078] Exemplarily, in one embodiment, please refer to Figure 3 , the linear groove 1111a extends along the length direction of the electrode sheet 111. In one embodiment, the linear groove 1111a extends in a direction intersecting the length direction of the electrode sheet 111. For example, please refer to Figure 4 , the linear groove 1111a extends along the width direction of the electrode sheet 111.
[0079] The projected shape of the groove 1111a can be adjusted and combined according to the roughness requirements. There can be only one type of projected shape of the groove 1111a in one active layer 1111. For example, there is only a dot-shaped groove 1111a in one active layer 1111. There can also be a combination of two or more projected shapes of the groove 1111a in one active layer 1111. For example, there can be a combination of dot-shaped grooves 1111a and linear grooves 1111a in one active layer 1111.
[0080] The number of the grooves 1111a can be one or at least two.
[0081] The distribution pattern of the multiple grooves 1111a is not limited. In one embodiment, please refer to Figure 5 , the multiple grooves 1111a are distributed in a two-dimensional matrix. For example, a part of the grooves 1111a are spaced apart along the length direction of the current collector 111 to form a row, and multiple rows of grooves 1111a are spaced apart along the width direction of the current collector 111. In one embodiment, the multiple grooves 1111a can also be distributed in concentric circles. The multiple grooves 1111a can also adopt other distribution patterns, which will not be elaborated here.
[0082] In one embodiment, active layers 1111 are provided on both surfaces of the current collector along the thickness direction; taking the plane perpendicular to the thickness direction of the current collector as the projection plane, the projections of the grooves 1111a of the two active layers 1111 are misaligned. That is to say, the projections of the grooves 1111a of the two active layers 1111 do not overlap. Designed in this way, it is avoided that the grooves 1111a of the two active layers 1111 overlap and cause local overpressure of the current collector 111.
[0083] Exemplarily, taking the formation of the grooves 1111a by rolling as an example, a pressing roller is provided on each side of the current collector 111 along the thickness direction, and there is a phase difference between the protrusions of the two pressing rollers. In this way, during the process of the pressing rollers rotating and rolling, the misalignment of the grooves 1111a of the two active layers 1111 of the current collector 111 along the thickness direction is achieved.
[0084] In one embodiment, please refer to Figures 3 to 5 , the depth of the grooves 1111a along the thickness direction is 0.5 μm to 5 μm. Exemplarily, the depth of the grooves 1111a along the thickness direction is 0.5 μm, 0.8 μm, 1.0 μm, 2.0 μm, 3.0 μm, 4.0 μm or 5.0 μm, etc. The depth of the grooves 1111a along the thickness direction is appropriate, matching the thickness size of the active layer 1111, being easy to roll into shape, and also being able to reduce the risk of the grooves 1111a affecting the current collector.
[0085] In one embodiment, the active layer 1111 is a spray-formed structure. In other words, the active layer 1111 is formed by spraying particles. By adopting the spray-forming process to form the active layer 1111, the roughness of the active layer 1111 can be adjusted by controlling the particle size and surface density of the particles, and the process is simple.
[0086] In one embodiment, the particle size of the particles of the negative electrode active layer can be 5.2 μm to 23.6 μm. Exemplarily, the particle size of the particles of the negative electrode active layer can be 5.2 μm, 6 μm, 10 μm, 15 μm, 20 μm, 22 μm or 23.6 μm, etc. For example, the median particle size of the particles of the negative electrode active layer can be 16.8 μm. Designed in this way, the active substances of the negative electrode active layer are easy to be manufactured into particles of the required particle size, being easy to meet the production process requirements and having a good yield.
[0087] In one embodiment, the particle size of the particles in the positive electrode active layer can be from 5.5 μm to 30.0 μm. Exemplarily, the particle size of the particles in the positive electrode active layer can be 5.5 μm, 6 μm, 10 μm, 15 μm, 20 μm, 25 μm, or 30 μm, etc. For example, the median particle size of the particles in the positive electrode active layer can be 10.8 μm. With such a design, the active material in the positive electrode active layer is easily made into particles of the required particle size, which is easy to meet the requirements of the production process and has a good yield rate.
[0088] In one embodiment, the areal density of the particles in the positive electrode active layer is 0.5×10^(-3) mg / mm 2 to 10×10^(-3) mg / mm 2 . Exemplarily, the areal density of the particles in the positive electrode active layer is 0.5×10^(-3) mg / mm 2 , 1×10^(-3) mg / mm 2 , 2×10^(-3) mg / mm 2 , 5×10^(-3) mg / mm 2 or 10×10^(-3) mg / mm 2 , etc. With such a design, it is easy to meet the requirements of the production process and has a good yield rate.
[0089] In one embodiment, the areal density of the particles in the negative electrode active layer is 0.5×10^(-3) mg / mm 2 to 10×10^(-3) mg / mm 2 . Exemplarily, the areal density of the particles in the negative electrode active layer is 0.5×10^(-3) mg / mm 2 , 1×10^(-3) mg / mm 2 , 2×10^(-3) mg / mm 2 , 5×10^(-3) mg / mm 2 or 10×10^(-3) mg / mm 2 , etc. With such a design, it is easy to meet the requirements of the production process and has a good yield rate.
[0090] The median particle size refers to the average particle size of the particles. The median particle size refers to the particle size corresponding to when the cumulative particle size distribution percentage in the sample reaches 50%.
[0091] The areal density refers to the mass per unit area of the material.
[0092] It should be noted that the particle size and areal density of the particles in the embodiments of the present application are both well-known definitions in the art, and can be measured by well-known methods in the art.
[0093] In one embodiment, the active layer 1111 includes an intermediate region and a peripheral region. The peripheral region surrounds the outer periphery of the intermediate region, and the roughness of the intermediate region is greater than that of the peripheral region. During the cycling of the battery cell 1, the central position of the electrode sheet 111 is more likely to expand and deform, and the degree of deformation is also greater closer to the central position, making it easy to separate from the separator 112 and cause wrinkles. Therefore, the roughness of the intermediate region is greater than that of the peripheral region, strengthening the adhesion performance between the intermediate region and the separator 112.
[0094] In one embodiment, the roughness of the intermediate region is 5 μm to 30 μm. The roughness of the intermediate region is 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 28 μm, or 30 μm, etc. With such a design, the roughness of the intermediate region is moderate and easy to manufacture and form.
[0095] In one embodiment, the roughness of the peripheral region is 1.5 μm to 15 μm. The roughness of the peripheral region is 1.5 μm, 2.0 μm, 5.0 μm, 8.0 μm, 10.0 μm, 12.0 μm, 12.5 μm, 13 μm, or 15 μm, etc. With such a design, the roughness of the peripheral region is moderate and easy to manufacture and form.
[0096] In one embodiment, the distance between the boundary line between the peripheral region and the intermediate region and the outer edge line of the active layer 1111 is L, where 0 mm < L ≤ 20 mm. Exemplarily, L is 1 mm, 2 mm, 5 mm, 7 mm, 10 mm, 15 mm, 18 mm, or 20 mm, etc. With such a design, the sizes of the intermediate region and the peripheral region are appropriate, and the intermediate region can cover the range where the deformation of the electrode sheet 111 is relatively large.
[0097] In one embodiment, please refer to Figure 2 and Figure 6 , the battery cell 1 includes a housing 12 and an electrolyte. Both the electrode assembly 11 and the electrolyte are located inside the housing 12. The active ions in the electrolyte migrate between the positive electrode active layer and the negative electrode active layer to achieve charge and discharge. The separator 112 allows the active ions to pass through.
[0098] The housing 12 has a hollow structure, and an accommodation space for accommodating the electrode assembly 11 and the electrolyte is formed inside it. The housing 12 can be of various shapes, such as a cuboid, etc.
[0099] In some embodiments, the housing 12 can be a rigid structure. Exemplarily, the housing 12 can be made of rigid materials such as aluminum and / or steel.
[0100] In some embodiments, please refer to Figure 2, the housing 12 includes a housing body 121 and an end cap 122. The housing body 121 can be a hollow structure with one end open, and the end cap 122 closes the open end of the housing body 121. In this way, the end cap 122 and the housing body 121 jointly define an accommodation space.
[0101] In some embodiments, the end cap 122 can be configured with a balance valve. The balance valve can pre-discharge some of the gas in the accommodation space, which is helpful for heat dissipation and avoiding the accumulation of combustible gas at high temperatures, and can increase the heat-resistant temperature range.
[0102] The balance valve includes but is not limited to a breathing valve or an explosion-proof valve, etc. The balance valve can be a one-way valve. The one-way valve can restrict the air flow in the accommodation space to flow out unidirectionally to the outside.
[0103] In one embodiment, the battery cell 1 can be a lithium-ion battery cell. That is to say, the active ions of the battery cell 1 can be lithium ions.
[0104] In one embodiment, the material of the positive active layer includes but is not limited to at least one of lithium manganate, lithium iron phosphate, and lithium manganese iron phosphate. The above materials have relatively low costs and relatively high energy densities.
[0105] The positive current collector is made of a conductive material. In some embodiments, the positive current collector can be a metal foil or a composite current collector. The metal foil can be aluminum, aluminum with silver surface treatment, or stainless steel, etc. The composite current collector can include a polymer material base layer and a metal layer. The metal layer can be aluminum, aluminum alloy, or nickel, etc. The polymer material base layer can be polypropylene, polyethylene terephthalate, or polyethylene, etc.
[0106] The negative current collector is made of a conductive material. In some embodiments, the negative current collectors can all be metal foils or composite current collectors. The metal foil can be copper or nickel, etc. The composite current collector can include a polymer material substrate and a metal layer. The metal layer can be copper or nickel, etc. The polymer material substrate can be polypropylene, polyethylene terephthalate, or polyethylene, etc.
[0107] In one embodiment, the positive electrode tab 111a includes a positive electrode lead connected to the positive current collector, and the negative electrode tab 111b includes a negative electrode lead connected to the negative current collector. The positive electrode lead and the negative electrode lead can conduct current out of the electrode assembly 11.
[0108] In some embodiments, please refer to Figure 2 and Figure 6 , the electrode assembly 11 is a wound structure. Exemplarily, the positive electrode tab 111a, the negative electrode tab 111b, and the separator 112 are wound into a wound structure.
[0109] In some embodiments, the electrode assembly 11 is a stacked structure.
[0110] Exemplarily, there are at least two positive electrode plates 111a, negative electrode plates 111b, and separators 112. A plurality of positive electrode plates 111a and a plurality of negative electrode plates 111b are alternately stacked, and one separator 112 is disposed between adjacent positive electrode plates 111a and negative electrode plates 111b to form a stacked structure.
[0111] Exemplarily, a plurality of positive electrode plates 111a may be provided, and the negative electrode plates 111b are folded to form a plurality of folded segments stacked on top of each other, and one positive electrode plate 111a is clamped between adjacent folded segments to form a stacked structure.
[0112] Exemplarily, both the positive electrode plate 111a and the negative electrode plate 111b are folded to form a plurality of folded segments stacked on top of each other, and are alternately nested with each other to form a stacked structure.
[0113] In an exemplary embodiment, the battery cell 1 is a lithium-ion battery cell. The battery cell 1 includes an electrode assembly 11, and the electrode assembly 11 includes electrode plates 111 and a separator 112. The electrode plates 111 include current collectors and active layers 1111. The active layers 1111 are provided on at least one surface of the current collector in the thickness direction. The roughness of the active layer 1111 is 1.5 μm to 30 μm. The separator 112 is located on the side away from the current collector in the thickness direction of the active layer 1111 and is bonded to the active layer 1111. The active layer 1111 is formed with grooves 1111a, and the grooves 1111a are a roll-formed structure. The active layers 1111 are provided on both surfaces of the current collector in the thickness direction; taking the plane perpendicular to the thickness direction of the current collector as the projection plane, the projections of the grooves 1111a of the two active layers 1111 are misaligned. The roughness of the active layer 1111 is relatively high. By increasing the roughness of the active layer 1111, the mechanical coupling effect between the electrode plate 111 and the separator 112 is increased, and the adhesion between the active layer 1111 and the separator 112 is increased, so as to improve the bonding performance between the electrode plate 111 and the separator 112, and reduce the risk of wrinkles generated on the electrode plate 111 due to full charge of the electrode assembly 11 and other conditions. The grooves 1111a are formed by a roll-forming process, which has a simple process, good controllability, and low cost. The projections of the grooves 1111a of the two active layers 1111 do not overlap. Designed in this way, it is avoided that the grooves 1111a of the two active layers 1111 overlap to cause local overpressure of the electrode plate 111.
[0114] The above embodiments are only used to illustrate the technical solutions of the present application, rather than limiting 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 described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the various embodiments of the present application. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any way.
Claims
1. A battery cell, characterized in that, Comprising an electrode assembly, the electrode assembly comprising: A pole piece, comprising a current collector and an active layer, the active layer being provided on at least one surface of the current collector in the thickness direction, the roughness of the active layer being 1.5 μm to 30 μm; the active layer comprises an intermediate region and an edge region, the edge region surrounding the outer periphery of the intermediate region, and the roughness of the intermediate region is greater than that of the edge region; A separator, located on the side of the active layer away from the current collector in the thickness direction and adhered to the active layer.
2. The battery cell according to claim 1, wherein The active layer is formed with grooves.
3. The battery cell according to claim 2, wherein, The grooves are roll-formed structures.
4. The battery cell according to claim 2, wherein, Taking the plane perpendicular to the thickness direction of the current collector as the projection plane, the projection shape of the grooves is dot-shaped or linear.
5. The battery cell according to claim 2, characterized in that, The active layer is provided on both surfaces of the current collector in the thickness direction; taking the plane perpendicular to the thickness direction of the current collector as the projection plane, the projections of the grooves of the two active layers are misaligned.
6. The battery cell according to claim 2, wherein The depth of the grooves in the thickness direction is 0.5 μm to 5 μm.
7. The battery cell according to claim 1, characterized in that, The active layer is a spray-formed structure.
8. The battery cell according to claim 1, wherein The roughness of the intermediate region is 5 μm to 30 μm; and / or, The roughness of the edge region is 1.5 μm to 15 μm.
9. The battery cell according to any one of claims 1 to 8, characterized in that, The pole piece is a positive pole piece, the current collector is a positive current collector, the active layer is a positive active layer, and the roughness of the positive active layer is 1.5 μm to 15 μm.
10. The battery cell according to any one of claims 1 to 8, characterized in that, The pole piece is a negative pole piece, the current collector is a negative current collector, the active layer is a negative active layer, and the roughness of the negative active layer is 5 μm to 30 μm.
11. A battery, characterized in that, Comprising the battery cell according to any one of claims 1 to 10.
12. An electrical device, characterized in that, Comprising the battery according to claim 11 for providing electrical energy.