Pole piece, battery cell, battery and electric equipment

Abstract

The utility model provides a pole piece, a battery cell, a battery and electric equipment. The pole piece comprises a current collector, an active material layer and a tab, the active material layer is arranged on at least one side of the current collector, and the current collector is provided with an empty foil section and a coating section used for coating the active material layer; a conductive thickening layer is arranged on at least one side of the empty foil section along the thickness direction of the pole piece, and at least part of the conductive thickening layer and at least part of the empty foil section corresponding to the conductive thickening layer jointly form the pole lug, so that the energy density of a battery cell can be ensured; and the over-current capability at the tab is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, and in particular to a pole piece, a battery core, a battery and electrical equipment. Background Art

[0002] Vehicles, such as new energy vehicles, generally include batteries, the batteries include pole pieces, the pole pieces include current collectors, active material layers and pole tabs, the current collectors have coated sections and empty foil sections, the active material layer is coated on the coated sections, and part of the empty foil sections is formed as pole tabs.

[0003] In the related art, in order to ensure the energy density of the battery, the entire current collector needs to be thinned. However, after the current collector is thinned, the thickness of the tab will also be thinned, which will reduce the current carrying capacity of the tab. When the battery is in use, the tab is prone to overheating and affecting the performance of the battery. Therefore, how to improve the current carrying capacity of the tab while ensuring the energy density of the battery has become a technical problem that needs to be solved urgently. Utility Model Content

[0004] In view of this, the embodiments of the utility model are dedicated to providing a pole piece, a battery cell, a battery and an electrical device, so as to improve the current flow capacity at the pole ear while ensuring the energy density of the battery cell.

[0005] In a first aspect, the utility model provides a pole piece, including a current collector, an active material layer and a pole ear;

[0006] The active material layer is disposed on at least one side of the current collector, and the current collector has a hollow foil section and a coating section for coating the active material layer;

[0007] A conductive thickening layer is provided on at least one side of the empty foil segment along the thickness direction of the pole piece, and at least part of the conductive thickening layer and at least part of the empty foil segment corresponding to the conductive thickening layer together form the pole lug.

[0008] Optionally, the conductive thickened layer is connected to the current collector by welding.

[0009] Optionally, the conductive thickening layer is connected to the current collector by ultrasonic roll welding.

[0010] Optionally, the material of the conductive thickening layer is the same as the material of the current collector;

[0011] Alternatively, the current collector is aluminum foil, and the conductive thickening layer is an aluminum foil layer;

[0012] Alternatively, the current collector is copper foil, and the conductive thickening layer is a copper foil layer.

[0013] Optionally, at least part of the active material layer and at least part of the conductive thickening layer are located on the same side of the current collector;

[0014] There is a preset gap between the conductive thickening layer and the active material layer located on the same side of the current collector; and / or, in the conductive thickening layer and the active material layer located on the same side of the current collector, the side of the conductive thickening layer facing away from the current collector does not protrude beyond the side of the active material layer facing away from the current collector.

[0015] In a second aspect, the utility model provides a battery cell, comprising the pole piece as described above.

[0016] Optionally, there are at least three pole pieces, and the at least three pole pieces are stacked in sequence, and two adjacent pole pieces have opposite polarities and are insulated from each other;

[0017] The pole ears on the two separated pole pieces are connected and used to be electrically connected to the poles on the battery top cover.

[0018] Optionally, the connection between the pole ears on the two separated pole pieces coincides with the connection between the conductive thickened layer and the empty foil segment;

[0019] And / or, the pole ears on the two separated pole pieces are connected by welding;

[0020] And / or, the battery cell has a first side and a second side opposite to each other, all the positive electrode tabs are located on the first side, and all the negative electrode tabs are located on the second side.

[0021] In a third aspect, the utility model provides a battery, comprising the battery cell as described above.

[0022] In a fourth aspect, the utility model provides an electrical device, comprising the battery as described above.

[0023] The pole piece, battery cell, battery and electrical equipment provided by the utility model are provided with a conductive thickening layer on at least one side of the empty foil segment of the current collector along the thickness direction of the pole piece, so that at least part of the conductive thickening layer and at least part of the empty foil segment corresponding to the conductive thickening layer are formed into a pole ear together, that is, by thickening the empty foil segment of the current collector, the pole ear is thickened, and the internal resistance of the battery can be reduced to a certain extent, so that the current flow capacity at the pole ear can be improved, thereby avoiding the situation that the temperature rise at the pole ear is too high when the battery is used, which affects the battery performance, ensures the safety of the battery, and prolongs the cycle life of the battery. Moreover, the improvement of the current flow capacity at the pole ear can also improve the fast charging performance and endurance performance of the battery to a certain extent. In addition, by thickening the pole ear, the connection area between the pole ear and the pole column is also increased, so that the connection strength and connection efficiency of the pole ear and the pole column can also be improved, and the bonding force between the two is improved, and the risk of tearing and disconnecting the pole ear and the pole column is reduced to a certain extent, and the charging and discharging capacity and service life of the battery are ensured.

[0024] That is to say, the utility model is configured in this way so that the coated section of the current collector can be thinned according to actual needs to improve the energy density and volume utilization of the battery, and at the same time, a conductive thickening layer is provided in the empty foil section of the current collector to achieve thickening of the tab, thereby improving the current carrying capacity of the tab, that is, while ensuring the energy density of the battery, the current carrying capacity at the tab is simultaneously improved. In other words, the above-mentioned configuration of the utility model can be compatible with the improvement of the energy density of the battery and the current carrying capacity at the tab. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the structure of a pole piece according to an embodiment of the utility model;

[0026] Figure 2 It is a schematic diagram of the structure of stacked pole pieces in a battery cell according to an embodiment of the utility model;

[0027] Figure 3 It is a structural schematic diagram of a battery cell in an embodiment of the utility model in which the connection between the pole ears on two separated pole pieces coincides with the connection between the conductive thickened layer and the empty foil segment;

[0028] Figure 4 It is a structural schematic diagram of a battery cell in an embodiment of the utility model in which the connection between the pole ears on two separated pole pieces and the connection between the conductive thickened layer and the hollow foil segment are staggered.

[0029] Among them, 100, battery cell; 101, first side; 102, second side; 10, pole piece; 1, pole ear; 2, current collector; 21, empty foil section; 22, coating section; 3, active material layer; 4, conductive thickening layer; 5, preset gap. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0031] Vehicles, such as new energy vehicles, generally include batteries, which may be lithium-ion batteries. The battery cell includes a positive electrode sheet, a negative electrode sheet and a separator. Both the positive electrode sheet and the negative electrode sheet include a current collector, an active material layer and a tab. The current collector has a coating section and a hollow foil section. The active material layer is coated on the coating section, and part of the hollow foil section is formed as a tab. Specifically, the separator is disposed between the positive electrode sheet and the negative electrode sheet. For example, the positive electrode sheet, the separator and the negative electrode sheet may be stacked in sequence in a preset direction to form a battery cell.

[0032] In the related art, in order to ensure the energy density of the battery, the entire current collector needs to be thinned. However, when the current collector is thinned, the thickness of the tab will also be thinned, which will reduce the current carrying capacity of the tab. When the battery is in use, the tab is prone to overheating and affecting the performance of the battery. Therefore, how to improve the current carrying capacity of the tab while ensuring the energy density of the battery has become a technical problem that needs to be solved urgently.

[0033] Based on this, an embodiment of the utility model provides a pole piece, a battery cell, a battery and an electrical device, by arranging a conductive thickening layer on at least one side of the hollow foil segment in the current collector along the thickness direction of the pole piece, and making at least part of the conductive thickening layer and at least part of the hollow foil segment together form a pole ear, so that the current flow capacity at the pole ear can be improved while ensuring the energy density of the battery cell.

[0034] The following is a detailed description of the pole piece, battery cell, battery and electrical equipment provided by the utility model through specific embodiments in conjunction with the accompanying drawings:

[0035] Reference Figures 1 to 4 As shown, this embodiment provides a pole piece for a battery cell. The pole piece 10 includes a current collector 2, an active material layer 3 and a pole ear 1.

[0036] Exemplarily, the electrode sheet 10 may be a positive electrode sheet or a negative electrode sheet, wherein the electrode tab on the positive electrode sheet is a positive electrode tab, and the electrode tab on the negative electrode sheet is a negative electrode tab.

[0037] The active material layer 3 is disposed on at least one side of the current collector 2 , and the current collector 2 has a hollow foil section 21 and a coating section 22 for coating the active material layer 3 .

[0038] Specifically, the current collector 2 has a thickness direction ( Figures 1 to 4 The two opposite sides in the coating section 22 can be used to coat the active material layer 3. Figures 1 to 4 As shown, the active material layer 3 can be provided on both sides of the coating section 22 (that is, the active material layer 3 is coated on both the upper side and the lower side of the coating section 22). Of course, the active material layer 3 can also be provided on only one side of the coating section 22 (that is, the active material layer 3 is coated on the upper side or the lower side of the coating section 22).

[0039] Specifically, a conductive thickening layer 4 is provided on at least one side of the empty foil segment 21 along the thickness direction of the pole piece 10 , and at least part of the conductive thickening layer 4 and at least part of the empty foil segment 21 corresponding to the conductive thickening layer 4 together form a pole lug 1 .

[0040] Such an arrangement can increase the thickness of the pole ear 1 to a certain extent, thereby improving the current flow capacity at the pole ear 1 and improving the problem of excessive temperature rise due to current flow at the pole ear 1. At the same time, by thickening the pole ear 1, the coating section 22 of the current collector 2 can be thinned while ensuring that the overall thickness of the pole piece 10 remains unchanged, so that the thickness of the active material layer 3 can be appropriately increased, thereby improving the carrying capacity of the pole piece 10 for the active material layer 3, and further improving the energy density of the battery.

[0041] Exemplarily, the battery may be a fast-charging battery such as a NCM (nickel-cobalt-manganese) ternary lithium battery or a lithium iron phosphate battery (LFP), and the shape of the battery may be a square shell, a blade, a cylinder, a soft pack, etc. For example, the charging time of the fast-charging battery may be 7.5 minutes, 10 minutes, 12 minutes, 15 minutes, etc., and the state of charge (SOC) may be 10-80%.

[0042] For example, when the battery is placed upside down so that electrolyte remains at the pole lug 1, under fast charging conditions, the thickness of the pole lug 1 increases, thereby avoiding the occurrence of high temperature at the pole lug 1 to a certain extent, thereby avoiding the electrolyte from being enriched at the pole lug 1 and causing a series of side reactions, thereby ensuring the battery cycle life.

[0043] The pole piece provided in this embodiment is provided with a conductive thickening layer 4 on at least one side of the empty foil segment 21 of the current collector 2 along the thickness direction of the pole piece 10, so that at least part of the conductive thickening layer 4 and at least part of the empty foil segment 21 corresponding to the conductive thickening layer 4 are formed into a pole ear 1 together, that is, by thickening the empty foil segment 21 of the current collector 2, the pole ear 1 is thickened, and the internal resistance of the battery can be reduced to a certain extent, so that the current flow capacity at the pole ear 1 can be improved, thereby avoiding the situation that the temperature rise at the pole ear 1 is too high when the battery is used, which affects the battery performance, thereby ensuring the safety of the battery and extending the cycle life of the battery. Moreover, the improvement of the current flow capacity at the pole ear 1 can also improve the fast charging performance and endurance performance of the battery to a certain extent. In addition, by thickening the pole ear 1, the connection area between the pole ear 1 and the pole column is also increased, so that the connection strength and connection efficiency between the pole ear 1 and the pole column can also be improved, and the bonding force between the two is improved, and the risk of tearing and disconnection of the pole ear 1 and the pole column is reduced to a certain extent, and the charging and discharging capacity and service life of the battery are guaranteed.

[0044] That is to say, the present embodiment is configured in such a way that, according to actual needs, the coated section 22 of the current collector 2 can be thinned to improve the energy density and volume utilization of the battery, and at the same time, the conductive thickening layer 4 is provided in the empty foil section 21 of the current collector 2 to achieve the thickening of the pole tab 1, thereby improving the current carrying capacity of the pole tab 1, that is, while ensuring the energy density of the battery, the current carrying capacity at the pole tab 1 is simultaneously improved. In other words, the above-mentioned configuration of the present embodiment can be compatible with the improvement of the energy density of the battery and the current carrying capacity at the pole tab 1 at the same time.

[0045] Exemplarily, in some embodiments, the conductive thickening layer 4 and the current collector 2 are split structures, that is, the conductive thickening layer 4 and the current collector 2 are formed separately, and then the two are connected together to achieve the thickening effect of the pole ear 1. Compared with the solution of integrally forming the conductive thickening layer and the current collector, the split structure makes it possible to flexibly connect the conductive thickening layer 4 on the current collector 2 according to actual needs, and the thickness of the conductive thickening layer 4 can be flexibly selected according to actual needs so that the thickness of the pole ear 1 meets the requirements.

[0046] In some embodiments, the conductive thickening layer 4 is connected to the current collector 2 by welding. Compared with the scheme of connecting the conductive thickening layer to the current collector by means of glue (such as conductive glue), the stability and reliability of the connection between the conductive thickening layer 4 and the current collector 2 can be enhanced to a certain extent, and the reliable thickening of the pole lug 1 is ensured. The welding connection method can improve the connection efficiency to a certain extent and ensure the stability of the pole lug 1.

[0047] In some embodiments, the conductive thickening layer 4 is connected to the current collector 2 by ultrasonic roll welding.

[0048] Among them, ultrasonic welding is a solid-state welding with low energy consumption. Therefore, through the above-mentioned setting, while realizing the connection of the conductive thickening layer 4 on the current collector 2 to increase the thickness of the pole ear 1, the energy consumption of the conductive thickening layer 4 during the connection can be reduced to a certain extent, and the welding effect is good and the welding stability is high, so that the connection reliability of the conductive thickening layer 4 on the current collector 2 can be ensured, and the thickening effect on the pole ear 1 is further ensured, so that the current flow capacity at the pole ear 1 and the energy density of the battery can be further improved.

[0049] Of course, in other implementations, the conductive thickened layer 4 may also be connected to the current collector 2 by laser welding.

[0050] In some embodiments, the material of the conductive thickening layer 4 is the same as that of the current collector 2. Since the temperature and chemical reaction of the same material during the melting process are relatively stable, the reliability and stability of the welding of the conductive thickening layer 4 and the current collector 2 can be improved to a certain extent, thereby ensuring the thickening effect of the tab 1. In addition, welding the same material can ensure the uniformity of the weld, which is conducive to improving the welding efficiency and quality, thereby improving the bonding force between the conductive thickening layer 4 and the current collector 2, and further ensuring the thickening effect of the tab 1.

[0051] The current collector 2 may be made of aluminum foil, and the conductive thickening layer 4 is an aluminum foil layer. Of course, in other embodiments, the current collector 2 may be made of copper foil, and the conductive thickening layer 4 is a copper foil layer.

[0052] When the current collector 2 is aluminum foil, the pole piece 10 can be formed as a positive pole piece, and the corresponding active material layer 3 can be made of positive active materials such as lithium cobalt oxide, ternary materials or lithium iron phosphate. When the current collector 2 is copper foil, the pole piece 10 can be formed as a negative pole piece, and the corresponding active material layer 3 can be made of negative active materials such as graphite and silicon-based materials.

[0053] For example, when the current collector 2 is aluminum foil, the thickness of the conductive thickening layer 4 can be 8-20 μm, and when the current collector 2 is copper foil, the thickness of the conductive thickening layer 4 can be 4.5-10 μm.

[0054] In some embodiments, reference Figures 1 to 4 As shown, at least part of the active material layer 3 and at least part of the conductive thickening layer 4 are located on the same side of the current collector 2. That is, the conductive thickening layer 4 and the active material layer 3 are both present on the same side of the current collector 2 in the thickness direction.

[0055] Specific reference Figures 1 to 4 There is a preset gap 5 between the conductive thickening layer 4 and the active material layer 3 on the same side of the current collector 2. The preset gap 5 is along Figures 1 to 4 The X direction is formed between the conductive thickening layer 4 and the active material layer 3.

[0056] This arrangement can avoid rolling up the pole piece 10 to a certain extent, and when there is a bent portion between the active material layer 3 and the conductive thickening layer 4, the bent portion is directly transferred to the conductive thickening layer 4, that is, the preset gap 5 can buffer the bent portion to a certain extent, ensuring the stability and reliability of the connection between the conductive thickening layer 4 and the current collector 2, thereby ensuring the thickening effect of the pole tab 1. Moreover, the preset gap 5 can also be used as a connection assembly gap, thereby improving the convenience of connecting the conductive thickening layer 4 to the empty foil section 21 to a certain extent, improving the connection efficiency of the conductive thickening layer 4 and the current collector 2, and improving the production efficiency of the pole tab 1.

[0057] Exemplarily, the conductive thickening layer 4 may be disposed on at least one side of the current collector 2. That is, the conductive thickening layer 4 may be disposed only on one side of the current collector 2, or may be disposed on both sides of the current collector 2 at the same time.

[0058] In some embodiments, reference Figures 1 to 4 As shown, in the conductive thickening layer 4 and the active material layer 3 located on the same side of the current collector 2 , the side of the conductive thickening layer 4 facing away from the current collector 2 does not protrude beyond the side of the active material layer 3 facing away from the current collector 2 .

[0059] With such an arrangement, when the pole piece 10 is rolled up on the roller for storage, a gap is formed between the corresponding conductive thickening layers 4 in two adjacent layers of the pole piece 10 in the radial direction of the roller, that is, the side of the conductive thickening layer 4 that is away from the current collector 2 at the corresponding position does not contact the current collector 2 of the adjacent layer, which is beneficial to ensure the reliable connection of the conductive thickening layer 4 on the current collector 2, and further ensures the thickening effect of the pole ear 1.

[0060] Continue to refer Figures 1 to 4 As shown, this embodiment further provides a battery cell, and the battery cell 100 includes a pole piece 10 .

[0061] The pole piece 10 has the same structure and implementation principle as the pole piece 10 provided in the above embodiment, and can bring the same or similar technical effects, which will not be described one by one here, and the details can be referred to the description of the above embodiment.

[0062] In some embodiments, reference Figures 2 to 4 As shown, there are at least three pole pieces 10, and the at least three pole pieces 10 are stacked in sequence, and the polarities of two adjacent pole pieces 10 are opposite and insulated from each other.

[0063] For example, all pole pieces 10 may be arranged along Figures 1 to 4 The stacking is done from top to bottom. Figures 2 to 4As shown, assuming that there are four electrode sheets 10, the electrode sheets 10 from top to bottom can be respectively a positive electrode sheet, a negative electrode sheet, a positive electrode sheet, and a negative electrode sheet.

[0064] The battery cell 100 may further include a diaphragm (not shown in the figure), and the diaphragm may be disposed between two adjacent pole pieces 10 to achieve insulation between the two adjacent pole pieces 10 .

[0065] In some embodiments, reference Figures 2 to 4 As shown, the pole ears 1 on the two separated pole pieces 10 are connected and used to be electrically connected to the poles on the battery top cover.

[0066] Specifically, refer to Figures 2 to 4 From top to bottom, the two separated pole pieces 10 may refer to the first pole piece 10 and the third pole piece 10; or may refer to the second pole piece 10 and the fourth pole piece 10. In other words, the pole lug 1 on the first pole piece 10 and the pole lug 1 on the third pole piece 10 may be connected to achieve folding, and then electrically connected to the pole column, and the pole lug 1 on the second pole piece 10 and the pole lug 1 on the fourth pole piece 10 may be connected, and then electrically connected to the pole column.

[0067] In this arrangement, before connecting the pole lugs 1 to the pole column, the pole lugs 1 on the pole pieces 10 with the same polarity are first connected and gathered together, and then all the gathered pole lugs 1 are connected to the pole column as a whole. This can ensure the current capacity at the pole lugs 1 to a certain extent. At the same time, this can also improve the convenience and connection efficiency of connecting the pole lugs 1 in the battery cell to the pole column to a certain extent, which is conducive to improving the assembly production efficiency of the battery. Moreover, this can also ensure that each pole lug 1 can be connected to the pole column without being missed, thereby ensuring the normal use of the battery.

[0068] For example, the number of stacked layers of positive electrode sheets in the battery cell 100 may be 10-120, and the number of stacked layers of negative electrode sheets may be 11-121.

[0069] In some embodiments, reference Figure 3 As shown, the connection between the pole ears 1 on the two separated pole pieces 10 (see Figure 3 and Figure 4 B) and the connection between the conductive thickening layer 4 and the empty foil section 21 (refer to Figures 1 to 4 A) coincides with each other.

[0070] Of course, in other embodiments, reference Figure 4 As shown, the connection between the pole ears 1 on two separated pole pieces 10 and the connection between the conductive thickened layer 4 and the hollow foil segment 21 can also be staggered.

[0071] Among them, when the connection between the pole ears 1 on the two separated pole pieces 10 coincides with the connection between the conductive thickening layer 4 and the empty foil segment 21, the pole ears 1 can be thickened to ensure the battery energy density and the current capacity of the pole ears 1, and improve the connection efficiency between the pole ears 1 and the pole column. Figure 4 In the scheme in which the connection between the pole ear 1 on the two separated pole pieces 10 and the connection between the conductive thickening layer 4 and the empty foil section 21 is staggered, it can also avoid the pole ear 1 along the Figures 1 to 4 The length dimension in the X direction shown is too large, which is beneficial to ensure the assembly efficiency of the battery. At the same time, it can also avoid the situation where the pole ear 1 is too long and the pole ear 1 is inserted upside down, causing a short circuit in the battery. In addition, it can also achieve a small volume of the battery to a certain extent, which is beneficial to further ensure the energy density and volume utilization of the entire battery.

[0072] In some embodiments, the pole ears 1 on two separated pole pieces 10 are connected by welding, which can enhance the stability and reliability of the pole ears 1 on the two separated pole pieces 10 when they are closed and connected to a certain extent, ensure the connection effect of the pole ears 1, and the welding connection method can improve the connection efficiency to a certain extent.

[0073] In some embodiments, reference Figures 2 to 4 As shown, the battery cell 100 has a first side 101 and a second side 102 opposite to each other, all the positive tabs are located on the first side 101 , and all the negative tabs are located on the second side 102 .

[0074] Such an arrangement can facilitate the connection between the pole tabs 1 with the same polarity, thereby improving the efficiency of the connection of the pole tabs 1, and further facilitating the improvement of the production efficiency of the entire battery.

[0075] Of course, in other implementations, all the positive electrode tabs and all the negative electrode tabs may be located on the first side 101 , or all the positive electrode tabs and all the negative electrode tabs may be located on the second side 102 .

[0076] Of course, in other implementations, the pole piece 10 may also be wound to form a wound battery cell.

[0077] This embodiment further provides a battery, which includes a battery cell 100 .

[0078] The battery cell 100 has the same structure and implementation principle as the battery cell 100 provided in the above embodiment, and can bring the same or similar technical effects, which will not be described in detail here, and the details can be referred to the description of the above embodiment.

[0079] This embodiment also provides an electric device, which includes a battery. The electric device may be a new energy vehicle, or may be a mobile terminal such as a mobile phone.

[0080] The structure and implementation principle of this battery are the same as those of the battery provided in the above embodiments, and can bring the same or similar technical effects, which will not be described one by one here, and specific details can be referred to the description of the above embodiments.

[0081] In this article, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, or it can be indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances. In addition, the orientation or position relationship indicated by the terms "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. are based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0082] In this article, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0083] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A pole piece, characterized in that: It comprises a current collector (2), an active material layer (3) and a tab (1); The active material layer (3) is arranged on at least one side of the current collector (2), and the current collector (2) has a hollow foil section (21) and a coating section (22) for coating the active material layer (3); A conductive thickening layer (4) is provided on at least one side of the empty foil segment (21) along the thickness direction of the pole piece (10), and at least a portion of the conductive thickening layer (4) and at least a portion of the empty foil segment (21) corresponding to the conductive thickening layer (4) together form the pole lug (1).

2. The pole piece according to claim 1, characterized in that: The conductive thickened layer (4) is connected to the current collector (2) by welding.

3. The pole piece according to claim 2, characterized in that: The conductive thickening layer (4) is connected to the current collector (2) by ultrasonic rolling welding.

4. The pole piece according to claim 2, characterized in that: The material of the conductive thickened layer (4) is the same as that of the current collector (2); Alternatively, the current collector (2) is an aluminum foil, and the conductive thickened layer (4) is an aluminum foil layer; Alternatively, the current collector (2) is copper foil, and the conductive thickening layer (4) is a copper foil layer.

5. The pole piece according to any one of claims 1 to 4, characterized in that: At least part of the active material layer (3) and at least part of the conductive thickening layer (4) are located on the same side of the current collector (2); A preset gap (5) is provided between the conductive thickening layer (4) and the active material layer (3) located on the same side of the current collector (2); and / or, in the conductive thickening layer (4) and the active material layer (3) located on the same side of the current collector (2), a side surface of the conductive thickening layer (4) facing away from the current collector (2) does not protrude beyond a side surface of the active material layer (3) facing away from the current collector (2).

6. A battery cell, characterized in that: It comprises a pole piece (10) as claimed in any one of claims 1 to 5.

7. The battery cell according to claim 6, characterized in that: There are at least three pole pieces (10), and the at least three pole pieces (10) are stacked in sequence, and two adjacent pole pieces (10) have opposite polarities and are insulated from each other; The pole ears (1) on the two separated pole pieces (10) are connected and used to be electrically connected to the poles on the top cover of the battery.

8. The battery cell according to claim 7, characterized in that: The connection point of the pole ears (1) on the two separated pole pieces (10) coincides with the connection point of the conductive thickened layer (4) and the hollow foil segment (21); And / or, the pole ears (1) on the two separated pole pieces (10) are connected by welding; And / or, the battery cell (100) has a first side (101) and a second side (102) opposite to each other, all positive electrode tabs are located on the first side (101), and all negative electrode tabs are located on the second side (102).

9. A battery, characterized in that: Comprising the battery cell (100) as claimed in any one of claims 6 to 8.

10. An electrical device, characterized in that: Comprising the battery as claimed in claim 9.

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