Battery cell pole piece, battery cell and secondary battery

Abstract

The utility model belongs to the technical field of batteries, and particularly relates to a battery cell pole piece, a battery cell and a secondary battery. Wherein the battery cell pole piece comprises a current collector and an active material layer arranged on at least one surface of the current collector; the active material layer comprises an inner layer and an outer layer which are laminated; the inner layer is arranged on the current collector; at least one liquid absorption conductive part is arranged between the inner layer and the outer layer; when the battery cell pole piece is wound into a roll core, the battery cell pole piece is provided with at least one corner section; and the liquid absorption conductive part is arranged at the corner section. According to the utility model, the liquid storage capacity can be improved; therefore, the liquid retention capacity of the corner section is improved, and the phenomenon of lithium precipitation by black spots at the corner can be improved; and the battery cycle performance is improved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to battery technical field especially relates to a kind of electric core pole piece, electric core and secondary battery. BACKGROUND

[0002] At present, lithium ion battery is composed of positive electrode, negative electrode, diaphragm, electrolyte and other components, through homogenate, coating, roll, slitting, winding, liquid injection, assembly, formation and other technological processes, the production of electric core is completed.Electric core energy density can be solved through the angle of each component material gram capacity, thickness etc.The energy density can be reached by introducing high gram capacity positive electrode material, improving positive electrode surface density, improving positive electrode compaction in positive electrode aspect.It should be noted that lithium ion battery is divided into hard-shell battery and soft package battery.

[0003] In part of prior art, with the increase of electric core cycle number, the space between pole piece is squeezed due to the expansion of positive pole piece and negative pole piece in the cycle process, which leads to the formation of broken bridge of electrolyte at corner, reduces the liquid storage capacity, and finally appears black spot lithium. UTILITY MODEL CONTENT

[0004] The utility model aims at: in view of the deficiency of prior art, provide a kind of electric core pole piece, can solve the technical problem of low liquid storage capacity of prior art.

[0005] To achieve the above object, the utility model adopts the following technical scheme:

[0006] A kind of electric core pole piece, including current collector and the active material layer of at least one surface of the current collector;The active material layer includes the inner layer and outer layer of laminated arrangement;The inner layer is set on the current collector;And at least one liquid-absorbing conductive component is provided between the inner layer and the outer layer;

[0007] When the electric core pole piece is wound into roll core, at least one corner section is formed on the electric core pole piece;And the liquid-absorbing conductive component is arranged in the corner section.

[0008] Preferably, the material of the inner layer is same with the material of the outer layer.

[0009] Preferably, the inner layer is provided with first groove on the side towards the outer layer;The liquid-absorbing conductive component is connected to the inside of the first groove;

[0010] And / or, the outer layer is provided with second groove on the side towards the inner layer;The liquid-absorbing conductive component is connected to the inside of the second groove.

[0011] Preferably, along the development direction of the electrode tab of the electric core, the relationship between the size L1 of the liquid-absorbing conductive component and the thickness h0 of the winding core satisfies: 0.5*h0≤L1≤2*h0.

[0012] Preferably, the relationship between the length L1 of the liquid-absorbing conductive component and the thickness h0 of the winding core satisfies: 0.5*h0≤L1≤2*h0.

[0013] Preferably, the liquid-absorbing conductive component comprises a heat-conducting insulating layer and a conductive agent layer connected to each other; the heat-conducting insulating layer is connected to the inner layer and / or the outer layer; and the conductive agent layer is connected to the inner layer and / or the outer layer.

[0014] Preferably, the heat-conducting insulating layer is one of alumina, magnesia, silicon nitride, silicon carbide and boehmite.

[0015] Preferably, the conductive agent layer is one of carbon black, conductive graphite, carbon fiber, carbon nanotube and graphene.

[0016] Preferably, the heat-conducting insulating layer and the conductive agent layer are stacked; the heat-conducting insulating layer is connected to the outer layer; and the conductive agent layer is connected to the inner layer; or the heat-conducting insulating layer is connected to the inner layer; and the conductive agent layer is connected to the outer layer.

[0017] Preferably, the number of the conductive agent layers is two; and the heat-conducting insulating layer is arranged between the conductive agent layers; one of the conductive agent layers is connected to the inner layer; and the other of the conductive agent layers is connected to the outer layer.

[0018] The utility model discloses a kind of electric core, including first pole piece and second pole piece and the isolation film between the first pole piece and the second pole piece;And the first pole piece, the isolation film and the second pole piece are sequentially stacked and wound to form winding core;The first pole piece and / or the second pole piece is the electrode tab of the electric core described above.

[0019] The utility model discloses a kind of battery, including the electric core.

[0020] The utility model has the advantages that at least one liquid-absorbing conductive component is additionally arranged on each corner section in the winding state, so that the liquid-absorbing conductive component storage capacity and efficiency of the corner section are effectively increased, the liquid retention capacity of the corner section is improved, and then the electrolyte stored in the liquid-absorbing conductive component can be gradually supplemented to the electrode tab in the circulation process, so as to facilitate the infiltration between the electrolyte and the electrode tab and improve the black spot lithium precipitation phenomenon at the corner, and the battery circulation performance is improved. BRIEF DESCRIPTION OF DRAWINGS

[0021] The utility model will be described below with reference to the drawings Figures 1-7To describe the features, advantages and technical effects of the exemplary embodiments of the present application.

[0022] Figure 1 A structure schematic view of the electrode piece of the battery cell according to an embodiment of the present application;

[0023] Figure 2 A structure schematic view of the electrode piece of the battery cell according to an embodiment of the present application;

[0024] Figure 3 A structure schematic view of the electrode piece of the battery cell according to an embodiment of the present application;

[0025] Figure 4 A structure schematic view of the liquid-absorbing and conductive component of the electrode piece of the battery cell according to an embodiment of the present application;

[0026] Figure 5 A structure schematic view of the liquid-absorbing and conductive component of the electrode piece of the battery cell according to an embodiment of the present application;

[0027] Figure 6 A structure schematic view of the battery cell according to an embodiment of the present application;

[0028] Figure 7 A structure schematic view of the battery cell before winding according to an embodiment of the present application.

[0029] In the figure: 1-collector; 2-active material layer; 21-inner layer; 211-first groove; 22-outer layer; 221-second groove; 3-liquid-absorbing and conductive component; 31-thermally conductive and insulating layer; 32-conductive agent layer; 41-corner segment; 42-straight segment; 100-first electrode piece; 200-second electrode piece; 300-separating film. DETAILED DESCRIPTION

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application; the description and the drawings of the specification and the appended claims should be considered in conjunction with the summary of the application and the abstract; the terms "comprising", "comprise" and "including", as well as any variations thereof, used in the present application are intended to cover a non-exclusive inclusion.

[0031] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified.

[0032] Reference to "an embodiment" herein means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase "in an embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily all referring to a common embodiment, or an embodiment that is independent of all other embodiments. One of ordinary skill in the art will readily recognize from the disclosure herein, that embodiments of the present application can be combined with embodiments of the other applications.

[0033] In the description of the embodiments of the application, the term "and / or" is merely an association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can mean that A exists alone, A and B exist together, and multiple cases exist alone. In addition, the character " / " in this paper generally means that the front and rear associated objects are "or" relationship.

[0034] In the description of the embodiments of the application, unless otherwise explicitly specified and limited, the technical terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanical connection, or it can be electrical connection; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the application can be understood according to the specific circumstances.

[0035] The following will be described in detail in combination with the accompanying drawings Figures 1-7 The utility model will be described in further detail, but not as the limitation of the utility model.

[0036] As shown in Figure 1 And 2 As shown in an embodiment of the utility model, the electrode tab of the battery cell includes a current collector 1 and an active material layer 2 arranged on at least one surface of the current collector 1; the active material layer 2 includes an inner layer 21 and an outer layer 22 arranged in sequence; the inner layer 21 is arranged on the current collector 1; and at least one liquid-absorbing conductive component 3 is arranged between the inner layer 21 and the outer layer 22.

[0037] When the electrode tab of the battery cell is wound into a roll core, the electrode tab has at least one corner segment 41 and a straight segment 42 arranged alternately; and the liquid-absorbing conductive component 3 is arranged on the corner segment 41.

[0038] The technical scheme of the utility model adds at least one liquid-absorbing conductive component on each corner segment in the winding state, which effectively increases the liquid storage capacity and efficiency of the liquid-absorbing conductive component of the corner segment, thereby improving the liquid retention capacity of the corner segment, and then the electrolyte stored in the liquid-absorbing conductive component can be gradually supplemented to the electrode tab in the circulation process, which is beneficial to the wetting action between the electrolyte and the electrode tab and improves the black spot lithium precipitation phenomenon at the corner; and the battery cycle performance is improved.

[0039] Specifically, in some embodiments, the material of the inner layer 21 is the same as that of the outer layer 22. That is, after the current collector 1 first coats the inner layer 21, the liquid-absorbing conductive component 3 is installed on the outside of the inner layer 21; then the outer layer 22 is coated to achieve the coating of the liquid-absorbing conductive component 3, and also to ensure the complete fusion between the inner layer 21 and the outer layer 22.

[0040] Specifically, in some embodiments, (not shown in the figure) the inner layer 21 has a first groove 211 on the side facing the outer layer 22; the liquid-absorbing conductive component 3 is connected to the inside of the first groove 211 and abuts against the outer layer 22. This structure can achieve assembly stability of the liquid-absorbing conductive component 3 and helps to ensure the flatness of the surface of the outer layer 22, improving the overall structural stability and safety of use. In other embodiments, (not shown in the figure) the outer layer 22 has a second groove 221 on the side facing the inner layer 21; the liquid-absorbing conductive component 3 is connected to the inside of the second groove 221 and abuts against the inner layer 21. This structure can achieve assembly stability of the liquid-absorbing conductive component 3 and helps to ensure the flatness of the surface of the outer layer 22, improving the overall structural stability and safety of use. In still other embodiments, such as Figure 3 As shown, the inner layer 21 has a first groove 211 on the side facing the outer layer 22; the outer layer 22 has a second groove 221 on the side facing the inner layer 21; one side of the liquid-absorbing conductive component 3 is connected to the interior of the first groove 211; the other side of the liquid-absorbing conductive component 3 is connected to the interior of the second groove 221. This structure can achieve assembly stability of the liquid-absorbing conductive component 3, and is conducive to ensuring the flatness of the surface of the outer layer 22, thereby improving the stability and safety of the overall structure.

[0041] Specifically, in some implementations, such as Figure 3 As shown, along the unfolding direction of the battery cell electrode, the relationship between the size (length) L1 of the liquid-absorbing conductive component and the thickness h0 of the core satisfies: 0.5*h0≤L1≤2*h0. Here, h1 can be 5%*h2, 6%*h2, 7%*h2, 10%*h2, 15%*h2, 20%*h2, etc. In other words, by controlling the thickness of the liquid-absorbing conductive component 3 to be within the range of 5% to 20% of the thickness of the active material layer 2, the effect of lithium plating during cycling can be better improved, enhancing the overall structural stability and safety. However, an excessively thick liquid-absorbing conductive component 3 will result in insufficient active material and a low CB value, leading to lithium plating; an excessively thin liquid-absorbing conductive component 3 will have poor liquid retention at the corners, affecting cycling performance.

[0042] Specifically, in some implementations, such as Figure 1 , 3As shown in Figure 6, the relationship between the length L1 of the liquid-absorbing conductive component 3 and the width h0 of the entire winding core satisfies: 0.5*h0≤L1≤2*h0. Where L1 can be 0.5*h0, 0.6*h0, 0.7*h0, 1.0*h0, 1.5*h0, 2.0*h0, etc. This structure, with liquid-absorbing conductive components 3 of a suitable length range in each turn, can ensure sufficient electrolyte storage, facilitating the wetting effect between the electrolyte and the electrode, improving the black spot lithium deposition phenomenon at corners, and enhancing battery cycle performance.

[0043] Specifically, in some implementations, such as Figure 1 and 4 As shown, the liquid-absorbing conductive component 3 includes a thermally conductive insulating layer 31 and a conductive agent layer 32 that are interconnected (including hybrid interconnection). The thermally conductive insulating layer 31 is connected to the inner layer 21 and / or the outer layer 22; the conductive agent layer 32 is connected to the inner layer 21 and / or the outer layer 22. The thermally conductive insulating layer 31 can be one or more of alumina, magnesium oxide, silicon nitride, silicon carbide, and boehmite; the conductive agent layer 32 can be one or more of carbon black, conductive graphite, carbon fiber (VGCF), carbon nanotubes (CNT), and graphene. The shape of the liquid-absorbing conductive component 3 can be dot-shaped, line-shaped, or rectangular block-shaped, etc., and is not limited to any particular shape here. In other words, this structure can improve the liquid retention level at the corner by combining one or more of carbon black, conductive graphite, carbon fiber (VGCF), carbon nanotubes (CNT) and graphene, as well as one or more of alumina, magnesium oxide, silicon nitride, silicon carbide and boehmite. Furthermore, as the cycle progresses, the electrolyte stored in the liquid-absorbing conductive component 3 will be gradually replenished to the electrode, improving the black spot lithium deposition at the corner.

[0044] Specifically, in some of these implementations, such as Figure 4 As shown, the thermally conductive insulating layer 31 and the conductive agent layer 32 are stacked sequentially; and the thermally conductive insulating layer 31 is connected to the outer layer 22; the conductive agent layer 32 is connected to the inner layer 21; or, the thermally conductive insulating layer 31 is connected to the inner layer 21; and the conductive agent layer 32 is connected to the outer layer 22. That is, by coating the conductive agent layer 32 first and then the thermally conductive insulating layer 31, the electrolyte retention level at the corner can be improved, and as the cycle continues, the electrolyte stored in the liquid-absorbing conductive component 3 will gradually replenish the electrode, improving the black spot lithium plating at the corner. In other embodiments, such as... Figure 5As shown, the number of the conductive agent layers 32 is two, and the thermally conductive insulating layer 31 is arranged between the conductive agent layers 32; one of the conductive agent layers 32 is connected to the inner layer 21; the other conductive agent layer 32 is connected to the outer layer 22. This structure realizes the improvement of the liquid storage level at the corner through the upper, middle and lower sandwiched layer forms, and with the circulation, the electrolyte stored in the liquid-absorbing conductive part 3 will gradually supplement to the pole piece, improving the black spot lithium precipitation at the corner. In another embodiment, the thermally conductive insulating layer 31 and the conductive agent layer 32 form a mixture in a predetermined ratio; the mixture is arranged between the outer layer 22 and the inner layer 21. Further, the predetermined ratio can be 1:1; 1:2; 1:3, etc. for the thermally conductive insulating layer 31: conductive agent layer 32. This structure is good for the pole piece to be well soaked by the electrolyte after the mixture is formed, and the lithium precipitation effect at the corner is good.

[0045] The utility model discloses a kind of battery, such as Figure 6 And 7 As shown, the battery includes first pole piece 100 and second pole piece 200 and the isolation film 300 arranged between first pole piece 100 and second pole piece 200;And first pole piece 100, isolation film 300 and second pole piece 200 are sequentially laminated and wound to form roll core;First pole piece 100 and / or second pole piece 200 are battery pole piece. The specific structure of the battery pole piece refers to the above-mentioned embodiments, since the present battery adopts all the technical solutions of the above-mentioned embodiments, it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be repeated here. Among them, the positive pole piece includes positive current collector and positive active material layer, and the positive active material layer is coated on the surface of the positive current collector;The positive active material can be lithium cobaltate, lithium iron phosphate, ternary lithium or lithium manganate, etc. The negative pole piece includes negative current collector and negative active material layer, and the negative active material layer is coated on the surface of the negative current collector;The material of the negative current collector can be copper, and the negative active material layer includes negative active material, which can be carbon or silicon, etc. The material of the isolation film 300 can be PP (polypropylene) or PE (polyethylene) or the like.

[0046] Example 1

[0047] Positive pole piece: active material LiCoO2, conductive agent superconducting carbon, conductive carbon nanotube, binder polyvinylidene fluoride (PVDF) are uniformly dispersed in N-methylpyrrolidone solvent system according to weight ratio 97.6:0.6:0.5:1.3, then cold-pressed and slitted to obtain positive pole piece.

[0048] Negative electrode sheet: The negative electrode active material, the conductive agent, and the binder are mixed in a weight ratio of 97.6:1.1:1.3 to prepare a negative electrode active material slurry, which is coated, cold-pressed, striped, laser-etched, and die-cut to obtain a negative electrode sheet. The negative electrode sheet includes a negative electrode current collector, and the surface of the negative electrode current collector is coated with a negative electrode active material layer formed by an inner layer and an outer layer; and at least one liquid-absorbing conductive member 3 formed by aluminum oxide as a thermally conductive insulating layer 31 and carbon nanotubes (CNT) as a conductive agent layer 32 between the inner layer and the outer layer; and the thickness ratio of the liquid-absorbing conductive member 3 to the negative (anode) active material layer is controlled to be 5%;

[0049] Separator film: The PE surface is coated with a ceramic mixture as a separator film.

[0050] Electrolyte: Ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), and propyl propionate (PP) are mixed in a volume ratio of 1:1:4:4, and then a fully dried lithium salt LiPF6 is dissolved in the mixed organic solvent in a proportion of 1 mol / L to prepare an electrolyte.

[0051] Full cell preparation: The above positive electrode sheet, separator film, and negative electrode sheet are laminated to make a bare cell, which is packaged and injected with electrolyte to make a finished lithium ion battery.

[0052] Lithium precipitation interface: obtained by disassembling the cell after 500 cycles.

[0053] Example 2

[0054] The difference between Example 2 and Example 1 is that the thickness ratio of the liquid-absorbing conductive member 3 to the negative (anode) active material layer is 8%.

[0055] Example 3

[0056] The difference between Example 3 and Example 1 is that the thickness ratio of the liquid-absorbing conductive member 3 to the negative (anode) active material layer is 10%.

[0057] Example 4

[0058] The difference between Example 4 and Example 1 is that the thickness ratio of the liquid-absorbing conductive member 3 to the negative (anode) active material layer is 12%.

[0059] Example 5

[0060] The difference between Example 5 and Example 1 is that the thickness ratio of the liquid-absorbing conductive member 3 to the negative (anode) active material layer is 15%.

[0061] Example 6

[0062] Example 6 differs from Example 1 in that the thickness ratio of the liquid-absorbing conductive member 3 to the negative electrode (anode) active material layer is 18%.

[0063] Example 7

[0064] Example 7 differs from Example 1 in that the thickness ratio of the liquid-absorbing conductive member 3 to the negative electrode (anode) active material layer is 20%.

[0065] Comparative Example 1

[0066] Comparative Example 1 differs from Example 1 in that the liquid-absorbing conductive member 3 is not provided between the inner layer 21 and the outer layer 22.

[0067] Comparative Example 2

[0068] Comparative Example 2 differs from Example 1 in that the thickness ratio of the liquid-absorbing conductive member 3 to the negative electrode (anode) active material layer is 2%.

[0069] Comparative Example 3

[0070] Comparative Example 3 differs from Example 1 in that the thickness ratio of the liquid-absorbing conductive member 3 to the negative electrode (anode) active material layer is 23%.

[0071] Comparative Example 4

[0072] Comparative Example 4 differs from Example 1 in that the thickness ratio of the liquid-absorbing conductive member 3 to the negative electrode (anode) active material layer is 25%.

[0073] Comparative Example 5

[0074] Comparative Example 5 differs from Example 1 in that the thickness ratio of the liquid-absorbing conductive member 3 to the negative electrode (anode) active material layer is 28%.

[0075] Table 1 Performance parameters of all examples and comparative examples

[0076]

[0077] From the above table, it can be seen that: 1. The negative plate in the battery cell includes a negative current collector, and the surface of the negative current collector is coated with a negative active material layer formed by an inner layer and an outer layer; and at least one liquid-absorbing conductive component 3 formed by aluminum oxide as a heat-conducting insulating layer 31 and carbon nanotubes (CNT) as a conductive agent layer 32 is coated between the inner layer and the outer layer, and the thickness is in the thickness range of 5% to 20% of the thickness of the anode active layer, which has a good effect of improving the cycle lithium precipitation. 2. Too thick liquid-absorbing conductive component 3 will cause the negative active material to be insufficient and the CB value to be insufficient, thereby causing lithium precipitation; too thin or no liquid-absorbing conductive component 3 causes the liquid retention effect at the corner to be unsatisfactory. 3. The battery cell corresponding to the liquid-absorbing conductive component 3 which is too thin or has no or generally too thick will appear corner black spot lithium precipitation at 300-400 cycles (cycles) of cycle; the battery cell corresponding to the liquid-absorbing conductive component 3 which is super-thick will appear corner black spot lithium precipitation at 200-300 cycles (cycles) of cycle.

[0078] The utility model also proposes a kind of secondary battery, the secondary battery includes battery cell, and the specific structure of the battery cell refers to above-mentioned embodiment, since the secondary battery of the present application adopts all technical solutions of above-mentioned all embodiments, at least has all beneficial effects brought by the technical solutions of above-mentioned embodiments, which will not be described one by one here.

[0079] Among them, the secondary battery (Rechargeable battery) is also called as rechargeable battery or storage battery, which refers to the battery that can be activated by charging after discharging to continue using.The reversibility of chemical reaction can be used to build a new battery, that is, after a chemical reaction is converted into electric energy, the chemical system can be repaired by electric energy, and then the chemical reaction is converted into electric energy, so it is called secondary battery (rechargeable battery).The main rechargeable batteries on the market include nickel-hydrogen battery, nickel-cadmium battery, lead-acid (or lead-acid) battery, lithium-ion battery, polymer lithium-ion battery, etc.

[0080] In addition, it should be understood that, although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity, and those skilled in the art should understand the specification as a whole, and the technical solutions in each embodiment can be combined appropriately to form other embodiments that can be understood by those skilled in the art.

[0081] According to the disclosure and teaching of the above description, the person skilled in the art of the present application can also change and modify the above embodiments. Therefore, the present application is not limited to the above specific embodiments, and any obvious improvement, replacement or modification made by the person skilled in the art on the basis of the present application belongs to the protection scope of the present application. In addition, although some specific terms are used in the specification, these terms are only for convenience of description and do not constitute any limitation on the present application.

Claims

1. An electrode tab of a battery cell, characterized by: The active material layer includes an inner layer and an outer layer arranged in a stack; the inner layer is arranged on the current collector; and at least one liquid-absorbing and conductive component is arranged between the inner layer and the outer layer. When the electrode sheet is wound into a roll core, the electrode sheet has at least one corner segment; and the liquid-absorbing and conductive component is arranged on the corner segment.

2. The electrode sheet of claim 1, wherein: The material of the inner layer is the same as that of the outer layer.

3. The electrode sheet of claim 1, wherein: The side of the inner layer facing the outer layer is provided with a first groove; and the liquid-absorbing and conductive component is connected to the inside of the first groove. The side of the outer layer facing the inner layer is provided with a second groove; and the liquid-absorbing and conductive component is connected to the inside of the second groove.

4. The electrode sheet of claim 1, wherein: The relationship between the thickness h1 of the liquid-absorbing and conductive component and the thickness h2 of the active material layer satisfies: 5%*h2≤h1≤20%*h2.

5. The electrode sheet of claim 1, wherein: In the unwinding direction of the electrode sheet, the relationship between the size L1 of the liquid-absorbing and conductive component and the thickness h0 of the roll core satisfies: 0.5*h0≤L1≤2*h0.

6. The electrode tab of any one of claims 1 to 5, wherein: The liquid-absorbing and conductive component includes a thermally conductive and insulating layer and a conductive agent layer connected to each other; the thermally conductive and insulating layer is connected to the inner layer and / or the outer layer; and the conductive agent layer is connected to the inner layer and / or the outer layer.

7. The electrode sheet of claim 6, wherein: The thermally conductive and insulating layer is one of alumina, magnesia, silicon nitride, silicon carbide, and boehmite. The conductive agent layer is one of carbon black, conductive graphite, carbon fiber, carbon nanotube, and graphene.

8. The electrode sheet of claim 6, wherein: The thermally conductive and insulating layer and the conductive agent layer are arranged in a stack; the thermally conductive and insulating layer is connected to the outer layer; and the conductive agent layer is connected to the inner layer; or the thermally conductive and insulating layer is connected to the inner layer; and the conductive agent layer is connected to the outer layer. The number of the conductive agent layers is two; and the thermally conductive and insulating layer is arranged between the conductive agent layers; one of the conductive agent layers is connected to the inner layer; and the other of the conductive agent layers is connected to the outer layer.

9. An electric cell characterized by: The first electrode sheet and the second electrode sheet and the separator film arranged between the first electrode sheet and the second electrode sheet; and the first electrode sheet, the separator film, and the second electrode sheet are sequentially arranged in a stack to form a roll core; the first electrode sheet and / or the second electrode sheet is the electrode sheet of any one of claims 1 to 8.

10. A secondary battery characterized by comprising: The battery cell includes the electrode sheet of claim 9.

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