Battery monomer, battery and electric device

Abstract

The utility model discloses a battery monomer, a battery and a power utilization device. The battery monomer comprises a shell and an electrode assembly accommodated in the shell, and the electrode assembly comprises a plurality of pole pieces. The pole piece comprises a current collector, a first film layer and a second film layer. The current collector comprises an insulating base layer, a first conducting layer and a second conducting layer, the first conducting layer and the second conducting layer are arranged on the two sides of the insulating base layer in the thickness direction of the insulating base layer respectively, and the insulating base layer, the first conducting layer and the second conducting layer are all of a porous structure. The first film layer is arranged on the side, away from the insulating base layer, of the first conductive layer. The second film layer is arranged on the side, away from the insulating base layer, of the second conductive layer. One of the first film layer and the second film layer is a positive electrode film layer, and the other one is a negative electrode film layer. And the current collector provides another migration path for active ions, so that high-rate charging and discharging are realized, and the charging and discharging performance of the battery monomer is improved.

Description

Technical Field

[0001] This application belongs to the technical field of batteries, and particularly relates to a battery cell, a battery, and an electrical device. Background Art

[0002] With the development of new energy technologies, batteries are more widely used. For example, batteries are not only applied to energy storage power systems such as hydropower, thermal power, wind power, and solar power plants, but also widely used in electric transportation such as electric bicycles, electric motorcycles, and electric vehicles, as well as in multiple fields such as military equipment and aerospace.

[0003] The charge and discharge performance of batteries is crucial. How to achieve a high level of fast charging while maintaining a high energy density is a challenge in the battery field. Summary of the Utility Model

[0004] Embodiments of this application provide a battery cell, a battery, and an electrical device, which can improve the charge and discharge performance of the battery cell.

[0005] According to the first aspect of this application, this application provides a battery cell, which includes a housing and an electrode assembly accommodated in the housing. The electrode assembly includes a plurality of electrode plates. The electrode plate includes a current collector, a first film layer, and a second film layer. The current collector includes an insulating base layer, a first conductive layer, and a second conductive layer. The first conductive layer and the second conductive layer are respectively disposed on both sides of the insulating base layer along its own thickness direction. The insulating base layer, the first conductive layer, and the second conductive layer are all porous structures. The first film layer is disposed on the side of the first conductive layer facing away from the insulating base layer. The second film layer is disposed on the side of the second conductive layer facing away from the insulating base layer. One of the first film layer and the second film layer is a positive electrode film layer, and the other is a negative electrode film layer.

[0006] In the embodiments of this application, on the basis of the traditional active ion migration path, the current collector provides another migration path for active ions, and the anode and cathode film layers are coated on the same current collector, shortening the migration path of active ions, which is beneficial to achieving high-rate charge and discharge and improving the charge and discharge performance of the battery cell. At the same time, the active ions migrating out from the positive electrode film layer are respectively embedded in different regions of the negative electrode film layer from opposite directions, which is beneficial to improving the utilization rate of the negative electrode film layer, reducing the deposition of active ions, and improving the capacity retention rate of the battery cell. Moreover, the technical solution provided by the embodiments of this application will not have an adverse effect on the energy density of the battery cell.

[0007] In some embodiments, the battery cell further includes a first tab and a second tab. The first tab is welded to the first conductive layer, and the second tab is welded to the second conductive layer, facilitating the extraction of the current of the first conductive layer and the second conductive layer through the first tab and the second tab respectively.

[0008] In some embodiments, the insulating base layer has a first end and a second end that are oppositely disposed along a first direction, the first direction being perpendicular to the thickness direction. In the first direction, the first end extends beyond the first conductive layer, and the first tab extends beyond the first end. The portion of the insulating base layer that protrudes beyond the second conductive layer can separate the first conductive layer from the second conductive layer and reduce the risk of the second tab overlapping with the first conductive layer.

[0009] In some embodiments, in the first direction, the first end extends beyond the second conductive layer, and the second tab extends beyond the first end; or, in the first direction, the second end extends beyond the second conductive layer, and the second tab extends beyond the second end. The portion of the insulating base layer that protrudes beyond the second conductive layer can separate the first conductive layer from the second conductive layer and reduce the risk of the second tab overlapping with the first conductive layer.

[0010] In some embodiments, the first tab and the second tab extend beyond the insulating base layer along the first direction, the first direction being perpendicular to the thickness direction; both ends of the insulating base layer along the first direction extend beyond the first conductive layer and the second conductive layer. The portions of the insulating base layer that protrude beyond the first conductive layer and the second conductive layer along the first direction can effectively separate the first conductive layer from the second conductive layer and reduce the risk of the first conductive layer and the second conductive layer overlapping due to problems such as uneven ends or burrs.

[0011] In some embodiments, the first tab and the second tab extend beyond the insulating base layer along the first direction, and both ends of the insulating base layer along its own length direction have bending portions; the bending portions extend toward the first conductive layer, and in the thickness direction, the extending ends of the bending portions are flush with or extend beyond the first conductive layer; or, the bending portions extend toward the second conductive layer, and in the thickness direction, the extending ends of the bending portions are flush with or extend beyond the second conductive layer; the first direction, the thickness direction, and the length direction are perpendicular to each other in pairs. The bending portions can separate the end portion of the first conductive layer along the length direction of the insulating base layer from the second conductive layer and the second film layer, reducing the risk of positive and negative electrode overlap during the winding and forming process of the electrode assembly; or, the bending portions can separate the end portion of the second conductive layer along the length direction of the insulating base layer from the first conductive layer, reducing the risk of positive and negative electrode overlap during the winding and forming process of the electrode assembly.

[0012] In some embodiments, the insulating base layer includes a first surface facing the first conductive layer. On one side of the insulating base layer facing the first conductive layer, there is a first recess. The first recess is recessed from the first surface and extends to one end of the insulating base layer along a first direction, where the first direction is perpendicular to the thickness direction. The first conductive layer is disposed on at least part of the inner wall of the first surface and the first recess. A part of the first tab is located in the first recess and is welded to the first conductive layer, and the first tab extends beyond the insulating base layer along the first direction. In the thickness direction, the first recess can provide at least part of the accommodation space for the first tab. The first tab, the insulating base layer, and the first conductive layer share at least part of the space in the thickness direction, which is beneficial to thinning the thickness of the current collector and improving the energy density of the battery cell. Moreover, when the first conductive layer is formed by chemical reaction deposition, the conductive layer deposited in the first recess is thicker than that deposited on the first surface, and the overcurrent capacity is stronger. Welding the first tab to the conductive layer in the first recess is beneficial to improving the overcurrent capacity of the battery cell.

[0013] In some embodiments, the insulating base layer has a first end and a second end oppositely arranged along the first direction. In the first direction, the first tab extends beyond the first end. The width of the first recess along a second direction gradually decreases in the direction from the second end to the first end, where the second direction, the first direction, and the thickness direction are perpendicular to each other pairwise. Thus, it is beneficial to both reducing the width of the part of the first tab protruding from the insulating base layer, thereby reducing the risk of the first tab affecting other structures of the battery cell (such as the liquid injection hole, the pressure relief mechanism, etc.), and increasing the size of the part of the first tab located in the first recess, thereby increasing the contact area between the first tab and the first conductive layer and improving the current collection capacity.

[0014] In some embodiments, the width of the first recess along the second direction gradually decreases in the recessed direction of the first recess, where the second direction, the first direction, and the thickness direction are perpendicular to each other pairwise. Thus, it is beneficial for the first conductive layer to be formed on the inner wall of the first recess, increasing the area of the first recess covered with the first conductive layer and improving the connection reliability between the first tab and the first conductive layer.

[0015] In some embodiments, the inner wall of the first recess includes a bottom wall and two side walls. The two side walls are connected to the bottom wall and are oppositely arranged along the second direction, where the second direction, the first direction, and the thickness direction are perpendicular to each other pairwise. A part of the first conductive layer is disposed on the bottom wall and the side walls. Thus, it is beneficial to increasing the connection area between the first tab and the first conductive layer and improving the connection reliability therebetween.

[0016] In some embodiments, in the thickness direction, the depth of the first recess recessed from the first surface is d1, the thickness of the first tab is d2, and the thickness of the insulating base layer is d3; wherein, d1≥d2, and / or, d1≤0.6d3. d1≥d2 can reduce the possibility that the first tab extends beyond the first recess in the thickness direction, and the first tab and the insulating base layer can maximize the space in the thickness direction, so as to minimize the thickness of the current collector as much as possible. d1≤0.6d3 ensures that the thickness of the thinning area of the insulating base layer is not too small to affect the insulation effect of the insulating base layer.

[0017] In some embodiments, in the second direction, the width of the first recess is w1, the width of the first tab is w2, and the second direction, the first direction, and the thickness direction are perpendicular to each other pairwise. Wherein, w1 and w2 satisfy: w2≤w1≤1.1w2. On the one hand, in the second direction Z, the first tab can be completely accommodated in the first recess without causing thickness stacking beyond the first recess; on the other hand, the first tab can also occupy most of the space of the first recess, reducing the size of the pits formed in the first recess, improving the electrolyte deposition phenomenon and the lithium plating problem, and enhancing the insulation effect.

[0018] In some embodiments, in the first direction, the height of the first recess is h1, the height of the first tab is h2, and h1 and h2 satisfy: 0.1h2≤h1≤0.5h2. Thereby, it is beneficial to improve the welding strength between the first tab and the first conductive layer, reduce the electrolyte deposition phenomenon, improve the lithium plating problem, and enhance the insulation effect.

[0019] In some embodiments, the insulating base layer includes a second surface and a second recess. The second surface is disposed opposite to the first surface in the thickness direction. The second recess is recessed from the second surface in the thickness direction and extends to one end of the insulating base layer in the first direction; the second conductive layer is disposed on at least a part of the inner wall of the second surface and the second recess; a part of the second tab is located in the second recess and welded to the second conductive layer, and the second tab extends beyond the insulating base layer in the first direction. In the thickness direction, the second recess can provide at least part of the accommodation space for the second tab, and the second tab, the insulating base layer, and the second conductive layer share at least part of the space in the thickness direction, which is beneficial to reducing the thickness of the current collector and improving the energy density and overcurrent capacity of the battery cell.

[0020] In some embodiments, the first recess and the second recess are located at the same end of the insulating base layer along the first direction and are completely staggered along the second direction. The first direction, the second direction, and the thickness direction are perpendicular to each other in pairs. The first tab and the second tab can respectively share the space in the thickness direction with different regions of the insulating base layer, which is beneficial to reducing the influence on the insulation isolation effect of the insulating base layer and is also beneficial to thinning the current collector and improving the energy density of the battery cell. Alternatively, the first recess and the second recess are respectively located at opposite ends of the insulating base layer along the first direction, and the first recess and the second recess do not affect each other, and the position selection of the first recess and the second recess is more flexible.

[0021] In some embodiments, in the thickness direction, the first film layer covers a part of the first tab. By covering the first tab with the first film layer, it is beneficial to improve the welding stability between the first tab and the first conductive layer.

[0022] In some embodiments, the insulating base layer includes a porous polymer film.

[0023] In some embodiments, the porosity of the insulating base layer is 30% - 70%; and / or, the porosity of the first conductive layer is 30% - 70%; and / or, the porosity of the second conductive layer is 30% - 70%.

[0024] In the embodiments of the present application, the porosity of the insulating base layer is set within the range of 30% - 70%. On the one hand, it can effectively isolate the first conductive layer and the second conductive layer and reduce the risk of short circuit. On the other hand, it is also beneficial to the passage of active ions, improving the passage efficiency of the active ions and the infiltration effect of the electrolyte. In the embodiments of the present application, the porosity of the first conductive layer and / or the second conductive layer is set within the range of 30% - 70%, which can achieve a balance between the conductivity of the first conductive layer and / or the second conductive layer and the passage efficiency of the active ions.

[0025] In some embodiments, the pore diameter of the insulating base layer is 20nm - 40nm; and / or, the pore diameter of the first conductive layer is 20nm - 40nm; and / or, the pore diameter of the second conductive layer is 20nm - 40nm.

[0026] In the embodiments of the present application, the pore diameter of the insulating base layer is set within the range of 20nm - 40nm. On the one hand, it can effectively isolate the first conductive layer and the second conductive layer and reduce the risk of short circuit. On the other hand, it is also beneficial to the passage of active ions, improving the passage efficiency of the active ions and the infiltration effect of the electrolyte.

[0027] In the embodiments of the present application, the pore diameter of the first conductive layer and / or the second conductive layer is set within the range of 20nm - 40nm, which can achieve a balance between the conductivity of the first conductive layer and / or the second conductive layer and the passage efficiency of the active ions.

[0028] In some embodiments, the first conductive layer is a coating structure electrolessly or electroplated on the insulating base layer; and / or, the second conductive layer is a coating structure electrolessly or electroplated on the insulating base layer. Since the insulating base layer has a porous structure, no coating can be formed at the pores on the first surface and the inner wall of the first recess, and the pore structure is retained. Thus, a first conductive layer with a porous structure can be formed, simplifying the preparation process of the first conductive layer and the connection between the first conductive layer and the insulating base layer.

[0029] In some embodiments, a plurality of electrode plates are stacked along the thickness direction; in two adjacent electrode plates, the first film layer of one electrode plate faces the second film layer of the other electrode plate. Thus, it is convenient for active ions to migrate between the first film layer of one electrode plate and the second film layer of the other electrode plate, further shortening the migration path of the active ions and improving the charge and discharge performance of the battery cell.

[0030] According to the second aspect of the present application, an embodiment of the present application further provides a battery, which includes a plurality of battery cells provided in any embodiment of the present application.

[0031] According to the third aspect of the present application, an embodiment of the present application further provides an electrical device, which includes a battery provided in any embodiment of the present application, and the battery is used to provide electrical energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required to be used in the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only 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.

[0033] Figure 1 It is a schematic structural diagram of a vehicle provided in some embodiments of the present application.

[0034] Figure 2 It is an exploded structural diagram of a battery provided in some embodiments of the present application.

[0035] Figure 3 It is an exploded structural diagram of a battery cell provided in some embodiments of the present application.

[0036] Figure 4 It is Figure 3 A schematic cross-sectional structure diagram of the electrode assembly of the battery cell shown.

[0037] Figure 5 It is Figure 3 A schematic structural diagram of the electrode plate of the battery cell shown.

[0038] Figure 6 It is Figure 5Schematic diagram of the exploded structure of the shown electrode sheet.

[0039] Figure 7 It is a schematic cross-sectional structure diagram of the electrode sheet of the battery cell provided by some embodiments of the present application.

[0040] Figure 8 It is a schematic cross-sectional structure diagram of the electrode sheet of the battery cell provided by other embodiments of the present application.

[0041] Figure 9 is Figure 8 An enlarged structure diagram of area A in

[0042] Figure 10 It is a schematic structure diagram of the electrode sheet of the battery cell provided by still other embodiments of the present application.

[0043] Figure 11 It is a schematic structure diagram of the electrode sheet of the battery cell provided by yet other embodiments of the present application.

[0044] In the drawings:

[0045] Vehicle 1000, battery 100, controller 200, motor 300;

[0046] Box body 10, first part 11, second part 12, battery cell 20, outer shell 21, housing 21a, cover plate 21b, electrode assembly 22, insulating base layer 221, first end 2211, second end 2212, bending part 2213, first surface 2214, first recess 2215, bottom wall 2215a, side wall 2215b, second surface 2216, second recess 2217, first conductive layer 222, second conductive layer 223, electrode sheet 22a, current collector 22b, first film layer 22c, second film layer 22d, separator 23, first tab 24, first part 241, second part 242, second tab 25, thickness direction X, first direction Y, second direction Z. Detailed implementation manners

[0047] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0048] Unless otherwise defined, all technical and scientific terms used in this application 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 specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification, claims, and drawings of this application are intended to cover non-exclusive inclusion. The terms "first", "second", etc. in the specification, claims, or drawings of this application are used to distinguish different objects and not to describe a specific order or primary-secondary relationship.

[0049] Reference to "embodiment" in this application means that a particular feature, structure, or characteristic described in connection with the embodiment can 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.

[0050] In the description of this application, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", "joined", and "attached" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. 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.

[0051] The term "and / or" in this application is merely a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally represents an "or" relationship between the associated objects before and after.

[0052] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, in different embodiments, the detailed description of the same components is omitted. It should be understood that the thickness, length, width, etc. of various components in the embodiments of this application shown in the drawings, as well as the overall thickness, length, width, etc. of the integrated device, are only for illustrative purposes and should not constitute any limitation to this application.

[0053] The term "a plurality of" as used in this application refers to two or more (including two).

[0054] In the embodiments of this application, "parallel" includes not only the case of absolute parallelism but also the case of approximately parallel as conventionally recognized in engineering; at the same time, "perpendicular" also includes not only the case of absolute perpendicularity but also the case of approximately perpendicular as conventionally recognized in engineering.

[0055] In the embodiments of the present application, the battery cell may be a secondary battery cell, which refers to a battery cell that can activate the active material through charging after discharging and can be used continuously.

[0056] The battery cell includes an electrode assembly and an electrolyte. The electrode assembly includes a positive electrode, a negative electrode, and a separator. The battery cell mainly operates by the movement of metal ions between the positive electrode and the negative electrode.

[0057] In the battery cell, the current collector is an indispensable part. It not only plays the role of carrying the active material but also collects the electrons generated by the electrochemical reaction and guides them to the external circuit, thus realizing the process of converting chemical energy into electrical energy.

[0058] The battery cell may be a lithium-ion battery cell, a sodium-ion battery cell, a sodium-lithium-ion battery cell, a lithium-metal battery cell, a sodium-metal battery cell, a lithium-sulfur battery cell, a magnesium-ion battery cell, a nickel-metal hydride battery cell, a nickel-cadmium battery cell, a lead-acid battery cell, etc. The embodiments of the present application do not limit this.

[0059] As an example, the battery cell may be a cylindrical battery cell, a prismatic battery cell, or a battery cell of other shapes. The prismatic battery cell includes a square-shell battery cell, a blade-shaped battery cell, a multi-prismatic battery, and the multi-prismatic battery is, for example, a hexagonal prism battery, etc. The present application has no special limitation.

[0060] The battery cell may be a hard-shell battery cell, a soft-pack battery cell, or a battery cell of other types.

[0061] The battery mentioned in the embodiments of the present application refers to a single physical module including multiple battery cells to provide higher voltage and capacity. For example, the battery mentioned in the present application may include a battery module or a battery pack, etc. The battery generally includes a box body for encapsulating one or more battery cells. The box body can prevent liquids or other foreign objects from affecting the charging or discharging of the battery cells.

[0062] In some embodiments, the box body may be a part of the chassis structure of a vehicle. For example, a part of the box body may become at least a part of the floor of the vehicle, or a part of the box body may become at least a part of the cross beam and longitudinal beam of the vehicle.

[0063] In some embodiments, the battery may be an energy storage device. The energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0064] High fast-charging performance is a common pursuit in battery design. Traditional current collectors lack porosity and are impermeable to electrolytes. During charging, active ions can only migrate from the positive electrode through the separator to the negative electrode; during discharging, active ions start from the negative electrode and return to the positive electrode through the separator. During the charge and discharge process of the battery, active ions can only perform unidirectional transmission, which limits the high-rate performance of the battery.

[0065] To improve the fast-charging performance of the battery, a feasible method is to heat the battery to improve the kinetic performance of the battery to achieve fast charging. However, at high temperatures, serious side reactions will occur at the battery material level, such as in the ternary system, which will lead to phenomena such as excessive metal dissolution. At the same time, it will also cause the decomposition of the electrolyte and serious gas generation inside the battery. Another feasible method is to achieve fast charging by thinning the thickness of the electrode sheet or reducing the compaction, etc., but this is at the cost of reducing the energy density of the battery. Therefore, it is difficult for the battery designed in this way to have both a high energy density and fast-charging performance, which restricts the development of the battery.

[0066] In view of this, the embodiments of the present application provide a technical solution in which the current collector is set to a porous structure. Specifically, the current collector includes an insulating base layer, a first conductive layer, and a second conductive layer, all of which are porous structures. Membrane layers are respectively provided on the sides of the first conductive layer and the second conductive layer facing away from the insulating base layer. The current collector provides another migration path for active ions, and the anode and cathode membrane layers are coated on the same current collector, shortening the migration path of active ions, which is beneficial to realizing high-rate charge and discharge and improving the charge and discharge performance of the battery cell. At the same time, the active ions migrating out of the positive electrode membrane layer are respectively embedded in different regions of the negative electrode membrane layer from opposite directions, which is beneficial to improving the utilization rate of the negative electrode membrane layer, reducing the deposition of active ions, and improving the capacity retention rate of the battery cell. And the technical solution provided by the embodiments of the present application will not have an adverse impact on the energy density of the battery cell.

[0067] The technical solution provided by the embodiments of the present application is applicable to battery cells, batteries, and electrical devices using the batteries. The electrical device can be a vehicle, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, etc. The vehicle can be a fuel vehicle, a gas vehicle, or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle, or an extended-range electric vehicle, etc.; the spacecraft includes an airplane, a rocket, a space shuttle, a spaceship, etc. The embodiments of the present application do not make special restrictions on the above electrical devices.

[0068] For the convenience of description, the following embodiments take the electrical device as a vehicle as an example for description.

[0069] Figure 1 It is a schematic structural diagram of a vehicle provided by some embodiments of the present application. Refer to Figure 1, the vehicle 1000 can be a fuel vehicle, a gas vehicle, or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle, an extended-range vehicle, etc. A battery 100 is disposed inside the vehicle 1000. The battery 100 can be disposed at the bottom, the head, or the tail of the vehicle 1000. The battery 100 can be used to supply power to the vehicle 1000. For example, the battery 100 can serve as the operating power source of the vehicle 1000. The vehicle 1000 can further 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-up, navigation, and driving of the vehicle 1000.

[0070] In some embodiments of the present application, the battery 100 can not only serve as the operating power source of the vehicle 1000, but also serve 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.

[0071] Figure 2 is a schematic exploded view of the battery provided in some embodiments of the present application. Refer to Figure 2 , the battery 100 includes a box body 10 and battery cells 20. The battery cells 20 are accommodated in the box body 10. Among them, the box body 10 is used to provide an accommodation space for the battery cells 20, and the box body 10 can adopt various structures. In some embodiments, the box body 10 can include a first part 11 and a second part 12. The first part 11 and the second part 12 cover each other, and the first part 11 and the second part 12 jointly define an accommodation space for accommodating the battery cells 20. The second part 12 can be a hollow structure with one end open, and the first part 11 can be a plate-like structure. The first part 11 covers the open side of the second part 12 so that the first part 11 and the second part 12 jointly define the accommodation space; the first part 11 and the second part 12 can also both be hollow structures with one side open, and the open side of the first part 11 covers the open side of the second part 12. Of course, the box body 10 formed by the first part 11 and the second part 12 can be of various shapes, such as a cylinder, a cuboid, etc.

[0072] In the battery 100, there can be multiple battery cells 20. The multiple battery cells 20 can be connected in series, in parallel, or in a series-parallel combination. A series-parallel combination means that there are both series and parallel connections among the multiple battery cells 20. The multiple battery cells 20 can be directly connected in series, in parallel, or in a series-parallel combination together, and then the whole formed by the multiple battery cells 20 is accommodated in the box body 10; of course, the battery 100 can also be that multiple battery cells 20 are first connected in series, in parallel, or in a series-parallel combination to form a battery module form, and then multiple battery modules are connected in series, in parallel, or in a series-parallel combination to form a whole and are accommodated in the box body 10. The battery 100 can further include other structures. For example, the battery 100 can further include a busbar component for realizing the electrical connection among the multiple battery cells 20.

[0073] Among them, each battery cell 20 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery or a magnesium-ion battery, but is not limited thereto. The battery cell 20 can be in the shape of a cylinder, a flat body, a cuboid or other shapes, etc.

[0074] Figure 3 It is a schematic exploded view of a battery cell provided by some embodiments of the present application. Referring to Figure 3 , the battery cell 20 includes a housing 21 and an electrode assembly 22, and the electrode assembly 22 is disposed inside the housing 21. The electrode assembly 22 includes a positive electrode and a negative electrode. During the charging and discharging process of the battery cell 20, active ions (such as lithium ions) are embedded and extracted back and forth between the positive electrode and the negative electrode.

[0075] The housing 21 has a hollow structure, and an accommodation space for accommodating the electrode assembly 22 and the electrolyte is formed inside it. The shape of the housing 21 can be determined according to the specific shape of the electrode assembly 22. For example, if the electrode assembly 22 is a cuboid structure, a cuboid housing can be selected.

[0076] The material of the housing 21 can be various. For example, the material of the housing 21 can be metal or plastic. Optionally, the material of the housing 21 can be copper, iron, aluminum, steel, aluminum alloy, etc. Exemplarily, the housing 21 can be a steel shell, an aluminum shell, a plastic shell (such as polypropylene), a composite metal shell (such as a copper-aluminum composite housing) or an aluminum plastic film, etc.

[0077] As an example, the housing 21 includes a housing body 21a and a cover plate 21b, the housing body 21a has an opening, and the cover plate 21b is used to cover the opening.

[0078] The housing body 21a is a component for cooperating with the cover plate 21b to form the internal cavity of the battery cell 20, and the formed internal cavity can be used to accommodate the electrode assembly 22, the electrolyte and other components.

[0079] The housing body 21a and the cover plate 21b can be independent components. Exemplarily, an opening can be provided on the housing body 21a, and the cover plate 21b is covered at the opening to form the internal cavity of the battery cell 20.

[0080] The shape of the cover plate 21b can be adapted to the shape of the housing body 21a to cooperate with the housing body 21a. The material of the cover plate 21b can be the same as or different from the material of the housing body 21a.

[0081] The cover plate 21b can be connected to the housing body 21a by welding, bonding, clamping or other means.

[0082] The electrode assembly 22 is a component in the battery cell 20 where an electrochemical reaction occurs. The housing 21 may contain one or more electrode assemblies 22. The electrode assembly 22 may have a wound structure, a laminated structure, a wound-laminated composite structure, or other structures.

[0083] The shape of the electrode assembly 22 may be cylindrical, flat, prismatic, or the like.

[0084] In some embodiments, the electrode assembly 22 further includes a separator 23 disposed between the positive electrode and the negative electrode. The separator 23 can reduce the risk of short circuit between the positive and negative electrodes and allow active ions to pass through.

[0085] Optionally, the separator 23 includes a separator membrane. There is no particular limitation on the type of the separator membrane in this application, and any well-known porous structure separator membrane with good chemical stability and mechanical stability can be selected.

[0086] The separator membrane can be a single-layer thin film or a multi-layer composite thin film, without particular limitation. When the separator membrane is a multi-layer composite thin film, the materials of each layer can be the same or different, without particular limitation.

[0087] The separator 23 can be a separate component located between the positive and negative electrodes or attached to the surfaces of the positive and negative electrodes.

[0088] In some embodiments, the separator 23 is a solid electrolyte. The solid electrolyte is disposed between the positive electrode and the negative electrode and functions to transport ions and isolate the positive and negative electrodes simultaneously.

[0089] Figure 4 is Figure 3 a schematic cross-sectional structure diagram of the electrode assembly of the battery cell shown, Figure 4 The straight arrows in indicate the migration direction of active ions. In some embodiments, referring to Figure 4 , the electrode assembly 22 includes a plurality of electrode tabs 22a. The electrode tab 22a includes a current collector 22b, a first film layer 22c, and a second film layer 22d. The current collector 22b includes an insulating base layer 221, a first conductive layer 222, and a second conductive layer 223. The first conductive layer 222 and the second conductive layer 223 are respectively disposed on both sides of the insulating base layer 221 along the thickness direction X of the insulating base layer 221. The insulating base layer 221, the first conductive layer 222, and the second conductive layer 223 are all porous structures. The first film layer 22c is disposed on the side of the first conductive layer 222 facing away from the insulating base layer 221. The second film layer 22d is disposed on the side of the second conductive layer 223 facing away from the insulating base layer 221. One of the first film layer 22c and the second film layer 22d is a positive electrode film layer, and the other is a negative electrode film layer.

[0090] The insulating base layer 221 is a porous structure made of an insulating material.

[0091] Optionally, the insulating base layer 221 includes a porous polymer film. The material of the insulating base layer 221 can be a nanoporous polymer with insulating properties, so as to facilitate the formation of a film layer with stable structure and relatively thin thickness. Exemplarily, the material of the insulating base layer 221 can be a composite material selected from one or more of polypropylene, polyethylene, polystyrene, polyether nitrile, polyurethane, polyphenylene ether, polyester, and polysulfone and their derivatives.

[0092] One of the first conductive layer 222 and the second conductive layer 223 is a positive electrode conductive layer, and the other is a negative electrode conductive layer. Among the first conductive layer 222 and the second conductive layer 223, the conductive layer connected to the positive electrode film layer in the first film layer 22c and the second film layer 22d is the positive electrode conductive layer, and the conductive layer connected to the negative electrode film layer in the first film layer 22c and the second film layer 22d is the negative electrode conductive layer.

[0093] The materials of the first conductive layer 222 and the second conductive layer 223 are different. Exemplarily, the positive electrode conductive layer can be an aluminum layer, and the negative electrode conductive layer can be a copper layer. The thickness of the positive electrode conductive layer can be greater than the thickness of the negative electrode conductive layer.

[0094] As an example, the positive electrode film layer in the first film layer 22c and the second film layer 22d may include a positive electrode active material, and the positive electrode active material may include at least one of the following materials: lithium-containing phosphate, lithium transition metal oxide, and their respective modified compounds. However, the present application is not limited to these materials, and other conventional materials that can be used as the battery positive electrode active material layer can also be used. These positive electrode active material layers can be used alone or in combination of two or more.

[0095] As an example, the negative electrode film layer in the first film layer 22c and the second film layer 22d may include a negative electrode active material, and the negative electrode active material can be a negative electrode active material well-known in the art for battery monomers.

[0096] The first conductive layer 222 can be attached to one surface of the insulating base layer 221 along the thickness direction X by electroplating, bonding, coating, or other suitable methods, and the second conductive layer 223 can be attached to the other surface of the insulating base layer 221 along the thickness direction X by electroplating, bonding, coating, or other suitable methods.

[0097] The first film layer 22c is coated on the surface of the first conductive layer 222 facing away from the insulating base layer 221, and the second film layer 22d is coated on the surface of the second conductive layer 223 facing away from the insulating base layer 221.

[0098] Since the insulating base layer 221, the first conductive layer 222, and the second conductive layer 223 are all porous structures, in addition to migrating between two adjacent pole pieces 22a, active ions (such as lithium ions) can also migrate on both sides of the current collector 22b through the pores of the first conductive layer 222, the insulating base layer 221, and the second conductive layer 223. Specifically, when the battery cell 20 is charged, some active ions can migrate from the positive electrode film layer along the traditional path through the separator 23 to the negative electrode film layer of the adjacent pole piece 22a, and be embedded in some areas of the negative electrode film layer far from the insulating base layer 221; some other active ions can directly migrate from the positive electrode film layer to the negative electrode film layer through the pores of the current collector 22b, and be embedded in some areas of the negative electrode film layer close to the insulating base layer 221. When the battery cell 20 is discharged, some active ions can migrate from the negative electrode film layer along the traditional path through the separator 23 to the positive electrode film layer of the adjacent pole piece 22a, and some other active ions can directly migrate from the negative electrode film layer to the positive electrode film layer through the pores of the current collector 22b.

[0099] Based on the traditional active ion migration path, the current collector 22b provides another migration path for active ions, and the anode and cathode film layers are coated on the same current collector 22b, shortening the migration path of active ions, which is beneficial to achieving high-rate charge and discharge and improving the charge and discharge performance of the battery cell 20. At the same time, the active ions migrating out of the positive electrode film layer are embedded in different areas of the negative electrode film layer from opposite directions, which is beneficial to improving the utilization rate of the negative electrode film layer, reducing the deposition of active ions, and improving the capacity retention rate of the battery cell 20. Moreover, the technical solution provided by the embodiments of the present application will not have an adverse impact on the energy density of the battery cell 20.

[0100] In some embodiments, a plurality of pole pieces 22a are stacked along the thickness direction X. In two adjacent pole pieces 22a, the first film layer 22c of one pole piece 22a faces the second film layer 22d of the other pole piece 22a. Thereby, it is convenient for active ions to migrate between the first film layer 22c of one pole piece 22a and the second film layer 22d of the other pole piece 22a, so as to further shorten the migration path of active ions and improve the charge and discharge performance of the battery cell 20.

[0101] Optionally, a plurality of pole pieces 22a and the separator 23 are stacked and wound.

[0102] Figure 5 is Figure 3 a schematic structural diagram of the pole piece of the battery cell shown, Figure 6 is Figure 5 a schematic exploded structural diagram of the pole piece shown. In some embodiments, refer to Figure 5 and Figure 6, the battery cell 20 further includes a first tab 24 and a second tab 25. The first tab 24 is welded to the first conductive layer 222, and the second tab 25 is welded to the second conductive layer 223.

[0103] Both the first tab 24 and the second tab 25 are connected to the current collector 22b through a welding process. The first tab 24 leads out the current on the first conductive layer 222 through welding with the first conductive layer 222. The second tab 25 leads out the current on the second conductive layer 223 through welding with the second conductive layer 223.

[0104] The first tab 24 and the second tab 25 can be respectively connected to two electrode terminals of the battery cell 20.

[0105] In some embodiments, the insulating base layer 221 has a first end 2211 and a second end 2212 that are oppositely arranged along the first direction Y, and the first direction Y is perpendicular to the thickness direction X. In the first direction Y, the first end 2211 extends beyond the first conductive layer 222, and the first tab 24 extends beyond the first end 2211.

[0106] The portion of the first tab 24 that protrudes from the first end 2211 in the first direction Y can be used to connect to an electrode lead-out structure.

[0107] Exemplarily, the first tab 24 may include a first portion 241 and a second portion 242 arranged along the first direction Y. The first portion 241 protrudes from the first end 2211 in the first direction Y. In the thickness direction X, the projection of the second portion 242 is located within the projection of the insulating base layer 22.

[0108] The second portion 242 is only partially welded to the first conductive layer 222, and the other portion of the second portion 242 that is not welded to the first conductive layer 222 can directly face the insulating base layer 221, that is, there is no first conductive layer 222 between the other portion of the second portion 242 and the insulating base layer 221.

[0109] Optionally, the other portion of the second portion 242 and the insulating base layer 221 can be connected by bonding or other suitable means to improve the connection strength between the first tab 24 and the current collector 22b and reduce the influence on the welding reliability between the first tab 24 and the first conductive layer 222 when the first tab 24 is bent and deformed.

[0110] In the direction from the second end 2212 to the first end 2211, a portion of the insulating base layer 221 protrudes from the first conductive layer 222. In other words, in the thickness direction X, the first conductive layer 222 only covers a portion of the insulating base layer 221. The portion of the insulating base layer 221 that protrudes from the first conductive layer 222 can separate the first conductive layer 222 from the second conductive layer 223 and reduce the risk of the first tab 24 overlapping with the second conductive layer 223.

[0111] In some embodiments, in the first direction Y, the first end 2211 extends beyond the second conductive layer 223, and the second tab 25 extends beyond the first end 2211.

[0112] The portion of the second tab 25 that protrudes beyond the first end 2211 in the first direction Y can be used to connect to the electrode lead-out structure.

[0113] Both the first tab 24 and the second tab 25 extend beyond the first end 2211 of the insulating base layer 221, and the first tab 24 and the second tab 25 are located at the same end of the current collector 22b in the first direction Y.

[0114] In the direction from the second end 2212 to the first end 2211, a portion of the insulating base layer 221 protrudes beyond the second conductive layer 223. In other words, in the thickness direction X, the second conductive layer 223 only covers a portion of the insulating base layer 221. The portion of the insulating base layer 221 that protrudes beyond the second conductive layer 223 can separate the first conductive layer 222 from the second conductive layer 223 and reduce the risk of the second tab 25 overlapping with the first conductive layer 222.

[0115] In some embodiments, in the first direction Y, the second end 2212 extends beyond the second conductive layer 223, and the second tab 25 extends beyond the second end 2212.

[0116] The first tab 24 and the second tab 25 are located at opposite ends of the current collector 22b in the first direction Y and protrude beyond the first end 2211 and the second end 2212 of the insulating base layer 221 in opposite directions, respectively.

[0117] In the direction from the first end 2211 to the second end 2212, a portion of the insulating base layer 221 protrudes beyond the second conductive layer 223. In other words, in the thickness direction X, the second conductive layer 223 only covers a portion of the insulating base layer 221. The portion of the insulating base layer 221 that protrudes beyond the second conductive layer 223 can separate the first conductive layer 222 from the second conductive layer 223 and reduce the risk of the second tab 25 overlapping with the first conductive layer 222.

[0118] In some embodiments, the first tab 24 and the second tab 25 extend beyond the insulating base layer 221 in the first direction Y, and the first direction Y is perpendicular to the thickness direction X. Both ends of the insulating base layer 221 in the first direction Y extend beyond the first conductive layer 222 and the second conductive layer 223.

[0119] The end of the first conductive layer 222 near the first end 2211 and the end of the second conductive layer 223 near the first end 2211 may be flush with each other or offset from each other along the first direction Y. The end of the first conductive layer 222 near the second end 2212 and the end of the second conductive layer 223 near the second end 2212 may be flush with each other or offset from each other along the first direction Y.

[0120] During the formation of the first conductive layer 222 and the second conductive layer 223, there may be phenomena such as unevenness, burrs, and rough edges at both ends of the first conductive layer 222 and the second conductive layer 223 along the first direction Y. A part of the insulating base layer 221 protrudes from the first conductive layer 222 and the second conductive layer 223 along the first direction Y. The part of the insulating base layer 221 that protrudes from the first conductive layer 222 and the second conductive layer 223 along the first direction Y can effectively separate the first conductive layer 222 and the second conductive layer 223, reducing the risk of overlap between the first conductive layer 222 and the second conductive layer 223 due to uneven ends or the presence of burrs.

[0121] Figure 7 It is a schematic cross-sectional structure diagram of the electrode sheet of the battery cell provided in some embodiments of the present application. In some embodiments, both ends of the insulating base layer 221 in its own length direction have bending portions 2213. The bending portions 2213 extend towards the first conductive layer 222. In the thickness direction X, the extending ends of the bending portions 2213 are flush with or extend beyond the first conductive layer 222. The first direction Y, the thickness direction X, and the length direction of the insulating base layer 221 are perpendicular to each other in pairs.

[0122] The bending portions 2213 may extend straight towards the first conductive layer 222, or may extend in a curved or bent manner towards the first conductive layer 222.

[0123] In the length direction of the insulating base layer 221, the first conductive layer 222 includes two first end faces. The bending portions 2213 may cover the first end faces of the first conductive layer 222, thereby separating the ends of the first conductive layer 222 in the length direction of the insulating base layer 221 from the second conductive layer 223 and the second film layer 22d, reducing the risk of positive and negative electrode overlap during the winding and forming process of the electrode assembly 22.

[0124] In some other embodiments, the bending portions 2213 may also extend towards the second conductive layer 223. In the thickness direction X, the extending ends of the bending portions 2213 are flush with or extend beyond the second conductive layer 223.

[0125] The bending portions 2213 may extend straight towards the second conductive layer 223, or may extend in a curved or bent manner towards the second conductive layer 223.

[0126] In the length direction of the insulating base layer 221, the second conductive layer 223 includes two second end faces, and the bending portion 2213 can cover the second end faces of the second conductive layer 223, so as to separate the end portion of the second conductive layer 223 along the length direction of the insulating base layer 221 from the first conductive layer 222, reducing the risk of positive and negative electrode overlap during the winding and forming process of the electrode assembly 22.

[0127] Figure 8 It is a schematic cross-sectional structure diagram of the electrode sheet of the battery cell provided in some other embodiments of the present application. Figure 9 Is Figure 8 The enlarged structure diagram of area A in. In some embodiments, refer to Figure 5 、 Figure 7 、 Figure 8 And Figure 9 The insulating base layer 221 includes a first surface 2214 facing the first conductive layer 222. A first recess 2215 is provided on the side of the insulating base layer 221 facing the first conductive layer 222. The first recess 2215 is recessed from the first surface 2214 and extends to one end of the insulating base layer 221 along the first direction Y, and the first direction Y is perpendicular to the thickness direction X. The first conductive layer 222 is provided on at least part of the inner wall of the first surface 2214 and the first recess 2215. A part of the first pole ear 24 is located in the first recess 2215 and is welded to the first conductive layer 222, and the first pole ear 24 extends beyond the insulating base layer 221 along the first direction Y.

[0128] Exemplarily, the first recess 2215 can extend to the first end 2211 of the insulating base layer 221, that is, the first recess 2215 penetrates the first end 2211 along the first direction Y. The first pole ear 24 extends beyond the first end 2211 along the first direction Y.

[0129] As another example, the first recess 2215 can extend to the second end 2212 of the insulating base layer 221, that is, the first recess 2215 penetrates the second end 2212 along the first direction Y. The first pole ear 24 extends beyond the second end 2212 along the first direction Y.

[0130] A part of the first conductive layer 222 is provided on the first surface 2214, and another part is provided on at least part of the inner wall of the first recess 2215. Optionally, the other part of the first conductive layer 222 can be at least provided on the bottom wall of the first recess 2215.

[0131] A part of the first pole ear 24 is welded to the part of the first conductive layer 222 located in the first recess 2215, which is convenient for the first pole ear 24 to lead out the current of the first conductive layer 222.

[0132] In an embodiment of the present application, a first recess 2215 is provided on the insulating base layer 221, and the first tab 24 is welded to a portion of the first conductive layer 222 located within the first recess 2215. In the thickness direction X, the first recess 2215 can provide at least partial accommodation space for the first tab 24. The first tab 24, the insulating base layer 221, and the first conductive layer 222 share at least part of the space in the thickness direction X, which is beneficial to thinning the thickness of the current collector 22b and improving the energy density of the battery cell 20.

[0133] Moreover, when the first conductive layer 222 is formed by chemical reaction deposition, the conductive layer deposited in the first recess 2215 will be thicker than the conductive layer deposited on the first surface 2214, and the current-carrying capacity will be stronger. Welding the first tab 24 to the conductive layer within the first recess 2215 is beneficial to improving the current-carrying capacity of the battery cell 20.

[0134] Figure 10 FIG. is a schematic structural diagram of the electrode sheet of the battery cell provided by some other embodiments of the present application. In some embodiments, referring to Figure 10 , the insulating base layer 221 has a first end 2211 and a second end 2212 that are oppositely arranged along the first direction Y. In the first direction Y, the first tab 24 extends beyond the first end 2211. The width of the first recess 2215 along the second direction Z gradually decreases in the direction from the second end 2212 to the first end 2211. Wherein, the second direction Z, the first direction Y, and the thickness direction X are perpendicular to each other in pairs.

[0135] In the embodiment of the present application, the width of the first recess 2215 refers to the dimension of the bottom wall of the first recess 2215 along the second direction Z. The width of the first recess 2215 is the smallest at the first end 2211 and the largest at a position far from the first end 2211. Exemplarily, in the thickness direction X, the projection of the first recess 2215 can be trapezoidal.

[0136] It can be understood that when the first conductive layer 222 is formed on one side of the insulating base layer 221, the portion of the first conductive layer 222 located within the first recess 2215 can match the size of the first recess 2215.

[0137] The portion of the first tab 24 located within the first recess 2215 can also match the size of the first recess 2215. Optionally, the second portion 242 of the first tab 24 matches the size of the first recess 2215. The width of the second portion 242 along the second direction Z gradually decreases in the direction from the second end 2212 to the first end 2211. The width of the first portion 241 of the first tab 24 along the second direction Z is the same as the minimum width of the second portion 242.

[0138] In the embodiment of the present application, the width of the first recess 2215 is set to gradually decrease in the direction from the second end 2212 to the first end 2211. This is beneficial for reducing the width of the portion of the first tab 24 protruding from the insulating base layer 221, thereby reducing the risk that the first tab 24 affects other structures of the battery cell 20 (such as the liquid injection hole, pressure relief mechanism, etc.). It is also beneficial for increasing the size of the portion of the first tab 24 located within the first recess 2215, thereby increasing the contact area between the first tab 24 and the first conductive layer 222 and improving the current collection ability.

[0139] In some embodiments, referring to Figure 8 and Figure 9 , the width of the first recess 2215 in the second direction Z gradually decreases along the recessed direction of the first recess 2215. The second direction Z, the first direction Y, and the thickness direction X are perpendicular to each other in pairs. Exemplarily, in a direction perpendicular to the thickness direction X, the cross-sectional shape of the first recess 2215 may be an inverted trapezoid.

[0140] The insulating base layer 221 includes a second surface 2216 opposite to the first surface 2214, and the recessed direction of the first recess 2215 is from the first surface 2214 to the second surface 2216.

[0141] Optionally, the first recess 2215 may include a bottom wall 2215a and two side walls 2215b. The two side walls 2215b are connected to the bottom wall 2215a and are oppositely arranged in the second direction Z. The side wall 2215b may be a plane extending obliquely with respect to the thickness direction X, or a convex or concave surface extending in a curved manner.

[0142] In the embodiment of the present application, the width of the first recess 2215 is set to gradually decrease along the recessed direction of the first recess 2215, which is beneficial for the first conductive layer 222 to be formed on the inner wall of the first recess 2215, increasing the area of the first recess 2215 covered with the first conductive layer 222, and improving the connection reliability between the first tab 24 and the first conductive layer 222.

[0143] In some embodiments, referring to Figure 8 , in the second direction Z, the width of the first recess 2215 is w1, and the width of the first tab 24 is w2. The second direction Z, the first direction Y, and the thickness direction X are perpendicular to each other in pairs, where w1 and w2 satisfy: w2 ≤ w1 ≤ 1.1w2.

[0144] Exemplarily, in the second direction Z, the widths of the first recess 2215 and the first tab 24 are balanced. The width w1 of the first recess 2215 and the width w2 of the first tab 24 are both constant values, and the constant value of w1 is greater than the constant value of w2.

[0145] As another example, in the second direction Z, the widths of the first recess 2215 and the first tab 24 are tapered. For example, the widths of both the first recess 2215 and the first tab 24 gradually decrease in the direction from the second end 2212 to the first end 2211. In these embodiments, the size relationship between w1 and w2 refers to the size relationship between w1 and w2 at the same position along the first direction Y.

[0146] If w1 is less than w2, in the second direction Z, a part of the first tab 24 will extend beyond the first recess 2215, and the part of the first tab 24 that extends beyond the first recess 2215 will cause a thickness superposition with the region of the insulating base layer 221 other than the first recess 2215, affecting the overall thickness of the current collector 22b and the energy density of the battery cell 20.

[0147] If w1 is much greater than w2, in the second direction Z, a large recess gap will be formed between the first tab 24 and the side wall of the first recess 2215, which is likely to deposit the electrolyte and cause lithium plating, and will also affect the insulation isolation effect of the insulating base layer 221.

[0148] In the embodiments of the present application, the width w1 of the first recess 2215 and the width w2 of the first tab 24 are set such that w2 ≤ w1 ≤ 1.1w2. On the one hand, in the second direction Z, the first tab 24 can be entirely received in the first recess 2215 without extending beyond the first recess 2215 to cause thickness superposition; on the other hand, the first tab 24 can also occupy most of the space of the first recess 2215, reducing the size of the recess formed in the first recess 2215, improving the electrolyte deposition phenomenon and the lithium plating problem, and enhancing the insulation isolation effect.

[0149] In some embodiments, the inner wall of the first recess 2215 includes a bottom wall 2215a and two side walls 2215b. The two side walls 2215b are connected to the bottom wall 2215a and are oppositely arranged along the second direction Z. The second direction Z, the first direction Y, and the thickness direction X are perpendicular to each other in pairs. A part of the first conductive layer 222 is disposed on the bottom wall 2215a and the side walls 2215b.

[0150] The first conductive layer 222 is disposed not only on the bottom wall 2215a of the first recess 2215 but also on the side walls 2215b of the first recess 2215. The surface of the first tab 24 facing the bottom wall 2215a can be welded to the first conductive layer 222 on the bottom wall 2215a, and the side surface of the second tab 25 facing the side wall 2215b can be welded to the first conductive layer 222 on the side wall 2215b, which is beneficial to increasing the connection area between the first tab 24 and the first conductive layer 222 and improving the connection reliability therebetween.

[0151] In some embodiments, refer to Figure 8 and Figure 9, in the thickness direction X, the depth of the first recess 2215 recessed from the first surface 2214 is d1, the thickness of the first tab 24 is d2, and the thickness of the insulating base layer 221 is d3. Wherein, d1≥d2, and / or, d1≤0.6d3.

[0152] Optionally, the surface of the first tab 24 facing away from the insulating base layer 221 may be flush with the surface of the first conductive layer 222 provided on the first surface 2214 facing away from the insulating base layer 221.

[0153] The depth d1 of the first recess 2215 is greater than or equal to the thickness d2 of the first tab 24, reducing the possibility that the first tab 24 extends beyond the first recess 2215 in the thickness direction X. The first tab 24 and the insulating base layer 221 can maximize the space in the thickness direction X, thereby thinning the current collector 22b as much as possible.

[0154] A thinning area is formed at the position of the insulating base layer 221 corresponding to the first recess 2215. If the thickness of the thinning area is too small, it may affect the insulation isolation effect of the insulating base layer 221 and cause the positive and negative electrodes to directly overlap. The depth d1 of the first recess 2215 is less than or equal to 0.6 times the thickness d3 of the insulating base layer 221, so that the thickness of the thinning area of the insulating base layer 221 is not too small to affect the insulation isolation effect of the insulating base layer 221.

[0155] In some embodiments, referring to Figure 10 , in the first direction Y, the height of the first recess 2215 is h1, and the height of the first tab 24 is h2, where h1 and h2 satisfy: 0.1h2≤h1≤0.5h2.

[0156] The smaller the height h1 of the first recess 2215, the smaller the size of the first conductive layer 222 formed on the inner wall of the first recess 2215 in the first direction Y, the smaller the size of the portion of the first tab 24 that can be accommodated in the first recess 2215, the smaller the welding area between the first tab 24 and the first conductive layer 222, and the smaller the connection strength between the two.

[0157] The height h1 of the first recess 2215 does not need to be too large either. When the height h2 of the first tab 24 is fixed, the larger the height h1 of the first recess 2215, the larger the size of the portion of the first tab 24 that can be accommodated in the first recess 2215, which will affect the length of the first tab 24 extending beyond the insulating base layer 221, and further affect the connection between the first tab 24 and the electrode lead-out structure. Or, in order to reduce the size of the portion of the first tab 24 accommodated in the first recess 2215 and leave some space gaps in the first recess 2215, it will cause electrolyte deposition and lithium plating problems, affecting the insulation isolation effect.

[0158] In the embodiment of the present application, the height h1 of the first recess 2215 and the height h2 of the first tab 24 are set such that 0.1h2 ≤ h1 ≤ 0.5h2, which is beneficial to improving the welding strength between the first tab 24 and the first conductive layer 222, reducing the electrolyte deposition phenomenon, improving the lithium plating problem, and enhancing the insulation isolation effect.

[0159] In some embodiments, referring to Figure 5 、 Figure 6 and Figure 8 the insulating base layer 221 includes a second surface 2216 and a second recess 2217. The second surface 2216 is disposed opposite to the first surface 2214 in the thickness direction X. The second recess 2217 is recessed from the second surface 2216 in the thickness direction X and extends to one end of the insulating base layer 221 in the first direction Y. The second conductive layer 223 is disposed on at least a part of the inner wall of the second surface 2216 and the second recess 2217. A part of the second tab 25 is located in the second recess 2217 and is welded to the second conductive layer 223, and the second tab 25 extends beyond the insulating base layer 221 in the first direction Y.

[0160] In the thickness direction X, the second recess 2217 can provide at least a part of the accommodation space for the second tab 25. The second tab 25, the insulating base layer 221, and the second conductive layer 223 share at least a part of the space in the thickness direction X, which is beneficial to thinning the thickness of the current collector 22b and improving the energy density of the battery cell 20.

[0161] Moreover, when the second conductive layer 223 is formed by chemical reaction deposition, the conductive layer deposited in the second recess 2217 is thicker than the conductive layer deposited on the first surface 2214 and has stronger current-carrying capacity. Welding the second tab 25 to the conductive layer in the second recess 2217 is beneficial to improving the current-carrying capacity of the battery cell 20.

[0162] In some embodiments, the second recess 2217 has the same structure as the first recess 2215, which will not be elaborated here.

[0163] In some embodiments, the structural, positional, and dimensional relationships between the second recess 2217 and the second tab 25 are the same as those between the first recess 2215 and the first tab 24, respectively, which will not be elaborated here.

[0164] In some embodiments, referring to Figure 5 and Figure 6 the first recess 2215 and the second recess 2217 are located at the same end of the insulating base layer 221 in the first direction Y and are completely staggered in the second direction Z. The first direction Y, the second direction Z, and the thickness direction X are perpendicular to each other in pairs.

[0165] The first tab 24 and the second tab 25 extend beyond the same end of the insulating base layer 221 in the first direction Y.

[0166] Exemplarily, the first recess 2215 and the second recess 2217 are located at the first end 2211 of the insulating base layer 221, and both the first tab 24 and the second tab 25 extend beyond the first end 2211.

[0167] As another example, the first recess 2215 and the second recess 2217 may also be located at the second end 2212 of the insulating base layer 221, and both the first tab 24 and the second tab 25 extend beyond the second end 2212.

[0168] It can be understood that the complete staggering of the first recess 2215 and the second recess 2217 along the second direction Z means that in the thickness direction X, the projections of the first recess 2215 and the second recess 2217 do not overlap.

[0169] If the projections of the first recess 2215 and the second recess 2217 overlap in the thickness direction X, the thickness of the insulating base layer 221 corresponding to the overlapping part of the two is very thin, and the insulation isolation effect is poor. Moreover, due to the thickness limitation of the insulating base layer 221, the recess depths of both the first recess 2215 and the second recess 2217 are limited. In the thickness direction X, the first tab 24 may extend beyond the first recess 2215, and the second tab 25 may extend beyond the second recess 2217, resulting in a larger thickness of the current collector 22b and affecting the energy density.

[0170] When the first recess 2215 and the second recess 2217 are located at the same end of the insulating base layer 221 along the first direction Y, in the embodiment of the present application, the first recess 2215 and the second recess 2217 are arranged to be completely staggered along the second direction Z. The first tab 24 and the second tab 25 can respectively share the space in the thickness direction X with different regions of the insulating base layer 221, which is beneficial to reducing the influence on the insulation isolation effect of the insulating base layer 221 and is also beneficial to thinning the current collector 22b and improving the energy density of the battery cell 20.

[0171] Figure 11 It is a schematic structural diagram of the electrode sheet of the battery cell provided in some other embodiments of the present application. In some other embodiments, refer to Figure 11 , the first recess 2215 and the second recess 2217 may also be respectively located at opposite ends of the insulating base layer 221 along the first direction Y. The first recess 2215 and the second recess 2217 will not affect each other, and the position selection of the first recess 2215 and the second recess 2217 is more flexible.

[0172] Exemplarily, the first recess 2215 and the second recess 2217 may be respectively at the first end 2211 and the second end 2212 of the insulating base layer 221, and the first tab 24 and the second tab 25 respectively extend beyond the first end 2211 and the second end 2212.

[0173] In some embodiments, in the thickness direction X, the first film layer 22c covers a part of the first tab 24.

[0174] After the first tab 24 is welded to the first conductive layer 222, the first film layer 22c is coated on the surface of the first conductive layer 222 facing away from the insulating base layer 221 and covers a part of the first tab 24.

[0175] In the thickness direction X, the projection of the first film layer 22c is located within the projection of the first conductive layer 222. Exemplarily, the two ends of the first film layer 22c along the first direction Y may be flush with the two ends of the first conductive layer 222 along the first direction Y respectively. As another example, the two ends of the first conductive layer 222 along the first direction Y may also extend beyond the two ends of the first film layer 22c along the first direction Y respectively, that is, there are certain regions at the two ends of the first conductive layer 222 along the first direction Y where the first film layer 22c is not provided.

[0176] By covering the first tab 24 with the first film layer 22c, it is beneficial to improve the welding stability between the first tab 24 and the first conductive layer 222.

[0177] In some embodiments, in the thickness direction X, the second film layer 22d covers a part of the second tab 25.

[0178] In the thickness direction X, the projection of the second film layer 22d is located within the projection of the second conductive layer 223.

[0179] By covering the second tab 25 with the second film layer 22d, it is beneficial to improve the welding stability between the second tab 25 and the second conductive layer 223.

[0180] In some embodiments, the porosity of the insulating base layer 221 is 30% - 70%.

[0181] Optionally, the porosity of the insulating base layer 221 can be 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65% or 70%, etc.

[0182] If the porosity of the insulating base layer 221 is too large, it may affect the insulation isolation effect between the first conductive layer 222 and the second conductive layer 223, and short - circuit phenomena are likely to occur. If the porosity of the insulating base layer 221 is too small, it will have a greater hindrance effect on the active ions, and the number of active ions directly transmitted through the current collector 22b is small.

[0183] In the embodiments of the present application, the porosity of the insulating base layer 221 is set within the range of 30% - 70%. On the one hand, it can effectively isolate the first conductive layer 222 and the second conductive layer 223, reducing the short - circuit risk. On the other hand, it is also beneficial for the active ions to pass through, improving the passing efficiency of the active ions and the infiltration effect of the electrolyte.

[0184] In some embodiments, the porosity of the first conductive layer 222 is 30% to 70%.

[0185] Optionally, the porosity of the first conductive layer 222 can be 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65% or 70%, etc.

[0186] In some embodiments, the porosity of the second conductive layer 223 is 30% to 70%.

[0187] Optionally, the porosity of the second conductive layer 223 can be 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65% or 70%, etc.

[0188] The porosity of the insulating base layer 221, the porosity of the first conductive layer 222 and the porosity of the second conductive layer 223 can be the same or slightly different.

[0189] If the porosity of the first conductive layer 222 and the porosity of the second conductive layer 223 are too large, it may affect the conductivity of the first conductive layer 222 and the second conductive layer 223, and affect the connection effect with the tab. If the porosity of the first conductive layer 222 and the porosity of the second conductive layer 223 are too small, it will have a greater hindrance to the active ions, and the number of active ions directly transmitted through the current collector 22b is small.

[0190] In the embodiments of the present application, the porosity of the first conductive layer 222 and / or the porosity of the second conductive layer 223 are set in the range of 30% to 70%, and a balance can be achieved between the conductivity of the first conductive layer 222 and / or the second conductive layer 223 and the passing efficiency of the active ions.

[0191] In some embodiments, the pore diameter of the insulating base layer 221 is 20 nm to 40 nm.

[0192] Optionally, the pore diameter of the insulating base layer 221 can be 20 nm, 25 nm, 30 nm, 35 nm, or 40 nm, etc.

[0193] The pore diameter of the insulating base layer 221 refers to the average pore diameter of the pores in the insulating base layer 221.

[0194] In the embodiments of the present application, the pore diameter of the insulating base layer 221 is set in the range of 20 nm to 40 nm. On the one hand, it can effectively isolate the first conductive layer 222 and the second conductive layer 223, reducing the short-circuit risk. On the other hand, it is beneficial for the active ions to pass through, improving the passing efficiency of the active ions and the infiltration effect of the electrolyte.

[0195] In some embodiments, the pore diameter of the first conductive layer 222 is 20 nm to 40 nm.

[0196] Optionally, the pore diameter of the first conductive layer 222 can be 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, etc.

[0197] The pore diameter of the first conductive layer 222 refers to the average pore diameter of the pores in the first conductive layer 222.

[0198] In some embodiments, the pore diameter of the second conductive layer 223 is 20 nm to 40 nm.

[0199] Optionally, the pore diameter of the second conductive layer 223 can be 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, etc.

[0200] The pore diameter of the second conductive layer 223 refers to the average pore diameter of the pores in the second conductive layer 223.

[0201] In the embodiments of the present application, setting the pore diameter of the first conductive layer 222 and / or the pore diameter of the second conductive layer 223 within the range of 20 nm to 40 nm can achieve a balance between the conductivity of the first conductive layer 222 and / or the second conductive layer 223 and the passing efficiency of active ions.

[0202] In some embodiments, the thickness of the first conductive layer 222 can be 3 μm to 5 μm to improve the conductivity of the first conductive layer 222. The thickness of the second conductive layer 223 can be 3 μm to 5 μm to improve the conductivity of the second conductive layer 223.

[0203] Exemplarily, the thickness of the first conductive layer 222 can be 3 μm, 4 μm, 5 μm, etc. The thickness of the second conductive layer 223 can be 3 μm, 4 μm, 5 μm, etc.

[0204] The thickness of the first conductive layer 222 and the thickness of the second conductive layer 223 can be the same or different.

[0205] In some embodiments, the thickness of the insulating base layer 221 can be 10 μm to 50 μm to improve the insulation isolation effect of the insulating base layer 221. Exemplarily, the thickness of the insulating base layer 221 can be 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, etc.

[0206] In some embodiments, the first conductive layer 222 is a plating structure chemically plated or electroplated on the insulating base layer 221.

[0207] The first conductive layer 222 is formed on at least part of the inner walls of the first surface 2214 and the first recess 2215 by electroless plating or electroplating. Since the insulating base layer 221 has a porous structure, no plating layer can be formed at the pores of the first surface 2214 and the inner walls of the first recess 2215, and the pore structure is retained. Thus, the first conductive layer 222 with a porous structure can be formed, simplifying the preparation process of the first conductive layer 222 and the connection between the first conductive layer 222 and the insulating base layer 221.

[0208] In some embodiments, the second conductive layer 223 is a plating layer structure formed on the insulating base layer 221 by electroless plating or electroplating.

[0209] The second conductive layer 223 is formed on at least part of the inner walls of the second surface 2216 and the second recess 2217 by electroless plating or electroplating. Since the insulating base layer 221 has a porous structure, no plating layer can be formed at the pores of the first surface 2214 and the inner walls of the second recess 2217, and the pore structure is retained. Thus, the second conductive layer 223 with a porous structure can be formed, simplifying the preparation process of the second conductive layer 223 and the connection between the second conductive layer 223 and the insulating base layer 221.

[0210] According to a second aspect of the present application, embodiments of the present application further provide a battery 100, which includes a plurality of battery cells 20 provided in any one of the embodiments of the present application.

[0211] According to a third aspect of the present application, embodiments of the present application further provide an electrical device, which includes the battery 100 provided in any one of the embodiments of the present application, and the battery 100 is used to provide electrical energy.

[0212] The embodiment of the present application provides a battery cell 20, which includes a shell 21, an electrode assembly 22 disposed in the shell 21, a first pole ear 24 and a second pole ear 25. The electrode assembly 22 includes a plurality of pole pieces 22a. The pole piece 22a includes a porous current collector 22b, a first film layer 22c and a second film layer 22d. The current collector 22b includes an insulating base layer 221, a first conductive layer 222 and a second conductive layer 223. The insulating base layer 221 is a nanoporous polymer material. The first conductive layer 222 and the second conductive layer 223 are respectively disposed on both sides of the insulating base layer 221 along its own thickness direction X, and the first conductive layer 222 and the second conductive layer 223 are both porous structures. The first pole ear 24 and the second pole ear 25 extend beyond the insulating base layer 221 along the first direction Y, and the first direction Y is perpendicular to the thickness direction X. Both ends of the insulating base layer 221 along the first direction Y extend beyond the first conductive layer 222 and the second conductive layer 223. The insulating base layer 221 includes a first surface 2214 facing the first conductive layer 222. A first recess 2215 is provided on the side of the insulating base layer 221 facing the first conductive layer 222. The first recess 2215 is recessed in the first surface 2214 and extends to one end of the insulating base layer 221 along the first direction Y. The first conductive layer 222 is provided on the first surface 2214 and at least part of the inner wall of the first recess 2215. A portion of the first pole tab 24 is located in the first recess 2215 and is welded to the first conductive layer 222. The first pole tab 24 extends beyond the insulating base layer 221 along the first direction Y. The first film layer 22c is provided on the side of the first conductive layer 222 away from the insulating base layer 221. The second film layer 22d is provided on the side of the second conductive layer 223 away from the insulating base layer 221. One of the first film layer 22c and the second film layer 22d is a positive electrode film layer, and the other is a negative electrode film layer.

[0213] In the second direction Z, the width of the first recess 2215 is w1, the width of the first pole tab 24 is w2, and w1 and w2 satisfy: w2≤w1≤1.1w2. In the thickness direction X, the depth of the first recess 2215 sunken into the first surface 2214 is d1, the thickness of the first pole tab 24 is d2, and the thickness of the insulating base layer 221 is d3, d1≥d2, and / or, d1≤0.6d3. In the first direction Y, the height of the first recess 2215 is h1, the height of the first pole tab 24 is h2, and h1 and h2 satisfy: 0.1h2≤h1≤0.5h2.

[0214] Finally, it should be noted that 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 described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be covered within the scope of the claims and the specification 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. The present application is not limited to the specific embodiments disclosed in the text, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery cell, characterized in that, It includes a housing and an electrode assembly accommodated in the housing. The electrode assembly includes a plurality of electrode plates, and the electrode plates include: A current collector, which includes an insulating base layer, a first conductive layer, and a second conductive layer. The first conductive layer and the second conductive layer are respectively disposed on both sides of the insulating base layer along its own thickness direction. The insulating base layer, the first conductive layer, and the second conductive layer are all porous structures; A first film layer disposed on the side of the first conductive layer facing away from the insulating base layer; and A second film layer disposed on the side of the second conductive layer facing away from the insulating base layer; One of the first film layer and the second film layer is a positive electrode film layer, and the other is a negative electrode film layer.

2. The battery cell according to claim 1, wherein The battery cell further includes a first pole ear and a second pole ear. The first pole ear is welded to the first conductive layer, and the second pole ear is welded to the second conductive layer.

3. The battery cell according to claim 2, wherein The insulating base layer has a first end and a second end that are oppositely disposed in a first direction. The first direction is perpendicular to the thickness direction. In the first direction, the first end extends beyond the first conductive layer, and the first pole ear extends beyond the first end.

4. The battery cell according to claim 3, wherein In the first direction, the first end extends beyond the second conductive layer, and the second pole ear extends beyond the first end; or In the first direction, the second end extends beyond the second conductive layer, and the second pole ear extends beyond the second end.

5. The battery cell according to claim 2, wherein The first pole ear and the second pole ear extend beyond the insulating base layer in a first direction, and the first direction is perpendicular to the thickness direction; Both ends of the insulating base layer in the first direction extend beyond the first conductive layer and the second conductive layer.

6. The battery cell according to claim 2, wherein The first pole ear and the second pole ear extend beyond the insulating base layer in a first direction. Both ends of the insulating base layer along its own length direction have bending portions; The bending portions extend towards the first conductive layer. In the thickness direction, the extending ends of the bending portions are flush with or extend beyond the first conductive layer; or, the bending portions extend towards the second conductive layer. In the thickness direction, the extending ends of the bending portions are flush with or extend beyond the second conductive layer; The first direction, the thickness direction, and the length direction are perpendicular to each other in pairs.

7. The battery cell according to claim 2, wherein The insulating base layer includes a first surface facing the first conductive layer. A first concave portion is provided on the side of the insulating base layer facing the first conductive layer. The first concave portion is recessed from the first surface and extends to one end of the insulating base layer in a first direction. The first direction is perpendicular to the thickness direction. The first conductive layer is disposed on at least part of the inner wall of the first surface and the first concave portion; A part of the first tab is located in the first recess and is welded to the first conductive layer, and the first tab extends beyond the insulating base layer along the first direction.

8. The battery cell according to claim 7, wherein the insulating base layer has a first end and a second end oppositely arranged along the first direction, and in the first direction, the first tab extends beyond the first end; the width of the first recess along the second direction gradually decreases in the direction from the second end to the first end, and the second direction, the first direction, and the thickness direction are perpendicular to each other in pairs.

9. The battery cell according to claim 7, wherein the width of the first recess along the second direction gradually decreases in the recess direction of the first recess, and the second direction, the first direction, and the thickness direction are perpendicular to each other in pairs.

10. The battery cell according to claim 7, wherein the inner wall of the first recess includes a bottom wall and two side walls, the two side walls are connected to the bottom wall and are oppositely arranged along the second direction, and the second direction, the first direction, and the thickness direction are perpendicular to each other in pairs; a part of the first conductive layer is provided on the bottom wall and the side walls.

11. The battery cell according to claim 7, wherein in the thickness direction, the depth of the first recess recessed from the first surface is d1, the thickness of the first tab is d2, and the thickness of the insulating base layer is d3; wherein, d1≥d2, and / or, d1≤0.6d3.

12. The battery cell according to claim 7, wherein in the second direction, the width of the first recess is w1, the width of the first tab is w2, and the second direction, the first direction, and the thickness direction are perpendicular to each other in pairs, wherein w1 and w2 satisfy: w2≤w1≤1.1w2.

13. The battery cell according to claim 7, wherein in the first direction, the height of the first recess is h1, the height of the first tab is h2, wherein h1 and h2 satisfy: 0.1h2≤h1≤0.5h2.

14. The battery cell according to claim 7, wherein the insulating base layer includes a second surface and a second recess, the second surface is oppositely arranged with the first surface along the thickness direction, the second recess is recessed from the second surface along the thickness direction and extends to one end of the insulating base layer along the first direction; the second conductive layer is provided on at least part of the inner walls of the second surface and the second recess; a part of the second tab is located in the second recess and is welded to the second conductive layer, and the second tab extends beyond the insulating base layer along the first direction.

15. The battery cell according to claim 14, wherein the first recess and the second recess are located at the same end of the insulating base layer along the first direction and are completely staggered along the second direction, and the first direction, the second direction, and the thickness direction are perpendicular to each other in pairs; or the first recess and the second recess are respectively located at opposite ends of the insulating base layer along the first direction.

16. The battery cell according to claim 2, wherein in the thickness direction, the first film layer covers a part of the first tab.

17. The battery cell according to claim 1, wherein the insulating base layer includes a porous polymer film.

18. The battery cell according to claim 1, wherein the porosity of the insulating base layer is 30% to 70%; and / or the porosity of the first conductive layer is 30% to 70%; and / or the porosity of the second conductive layer is 30% to 70%.

19. The battery cell according to claim 1, wherein the pore size of the insulating base layer is 20 nm to 40 nm; and / or the pore size of the first conductive layer is 20 nm to 40 nm; and / or the pore size of the second conductive layer is 20 nm to 40 nm.

20. The battery cell according to claim 1, wherein the first conductive layer is a plating structure electrolessly plated or electroplated on the insulating base layer; and / or the second conductive layer is a plating structure electrolessly plated or electroplated on the insulating base layer.

21. The battery cell according to claim 1, wherein the plurality of electrode plates are stacked in the thickness direction; in two adjacent electrode plates, the first film layer of one electrode plate faces the second film layer of the other electrode plate.

22. A battery, characterized in that, Comprising a plurality of battery cells according to any one of claims 1-21.

23. An electrical device, characterized in that, Comprising the battery according to claim 22, the battery being used to provide electrical energy.

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