Battery

Abstract

The utility model provides a battery which comprises a first pole piece unit, the first pole piece unit comprises a first current collector, a first active material layer, a first tab and first notches, the first tab is connected to the first current collector, and at least two first notches are overlapped in the thickness direction of the first current collector to form a first accommodating groove; the at least two first tabs are mutually connected to form a first tab group, and the first tab group is positioned in the first accommodating groove; the first pole piece unit is provided with a first surface and a second surface which are opposite to each other, the first active substance layer comprises a first active coating and a second active coating, the first active coating is arranged on the first surface, and the second active coating is arranged on the second surface; the side, close to the first tab, of the first active coating is provided with a first side edge, the side, close to the first tab, of the second active coating is provided with a second side edge, and the first side edge and the second side edge are staggered in the first direction. The battery provided by the utility model is relatively high in energy density, and the cleaning effect of the first pole piece unit is relatively good.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery. Background Art

[0002] At present, people have increasingly higher requirements for the battery life of electrical devices, so high energy density is still one of the main development directions of lithium-ion batteries.

[0003] In the related art, a lithium-ion battery mainly includes a battery case and a battery cell. The battery cell and the electrolyte are encapsulated in the battery case. The battery cell may include a positive electrode sheet, a separator and a negative electrode sheet. The positive electrode sheet, the separator and the negative electrode sheet are sequentially stacked and then wound or laminated. Both the positive electrode sheet and the negative electrode sheet may include a foil and an active substance coated on the surface of the foil. During coating, a partial empty foil area is reserved on one side of the electrode sheet in the length direction. After that, part of the active substance is washed off and die-cutting is performed. The foil may form a current collector and a foil pole ear respectively. The active substance covers the current collector. After a plurality of foil pole ears are bent and welded together, a pole ear group may be formed. The pole ear group is connected to an external device through a switching pole ear, thereby drawing out the current of the battery cell.

[0004] Since the tab group needs to occupy part of the space inside the battery casing, the ineffective volume of the battery is increased, thereby reducing the energy density of the battery. Utility Model Content

[0005] Based on this, the present application provides a battery to solve the deficiencies of the related art.

[0006] The battery provided in the embodiment of the present application comprises a first pole piece unit and a second pole piece unit with opposite polarities, the first pole piece unit comprises a first current collector, a first active material layer, a plurality of first pole tabs and a plurality of first notches, the second pole piece unit comprises a plurality of second pole tabs, the first pole tabs are connected to the first current collector, the plurality of first notches overlap along the thickness direction of the first current collector to form a first receiving groove, the plurality of first pole tabs are connected to each other to form a first pole tab group, and the first pole tab group is at least partially located in the first receiving groove;

[0007] The first pole piece unit has a first surface and a second surface opposite to each other, the first active material layer includes a first active coating and a second active coating, the first active coating is arranged on the first surface, and the second active coating is arranged on the second surface;

[0008] The first active coating has a first side edge on one side close to the first pole ear, and the second active coating has a second side edge on one side close to the first pole ear. Both the first side edge and the second side edge extend along the second direction, and the first side edge and the second side edge are staggered along the first direction.

[0009] In a possible implementation, along the first direction, a distance between the first side edge and the second side edge is greater than or equal to 0.5 mm and less than or equal to 2.5 mm.

[0010] In a possible implementation, the first pole piece unit further includes an insulating layer, the insulating layer includes a first insulating coating, the first insulating coating is disposed on the first surface and adjacent to the first side, and a projection of the second side on the first insulating coating is located within the first insulating coating.

[0011] In a possible implementation, the insulating layer further includes a second insulating coating layer, and the second insulating coating layer is disposed on the second surface and is adjacent to the second side edge.

[0012] In a possible implementation, along the first direction, a ratio of an extension length of the first insulating coating layer to an extension length of the second insulating coating layer is greater than or equal to 1.01 and less than or equal to 4.

[0013] In a possible implementation, the first insulating coating includes a first region and a second region adjacent to each other, a projection of the first region on the thickness of the first pole piece unit covers the first current collector, and a projection of the second region on the thickness of the first pole piece unit covers the first pole ear;

[0014] There is a distance between the side of the first region along the first direction and the side of the first notch along the first direction.

[0015] In one possible implementation, the second active coating includes a first coating area and a second coating area adjacent to each other, the first coating area is located at the first electrode ear, and the second coating area is located at the first current collector. Along the first direction, the extension length of the first coating area is greater than or equal to 0.1 mm and less than or equal to 1 mm.

[0016] In a possible implementation, a ratio of the thickness of the insulating layer to the thickness of the first active material layer is greater than or equal to 0.1 and less than or equal to 0.9;

[0017] and / or, along the second direction, a ratio of an extension length of the first notch to an extension length of the insulating layer is greater than or equal to 1.2 and less than or equal to 3.5;

[0018] and / or, along the second direction, a ratio of an extension length of the insulating layer to an extension length of the first electrode tab is greater than or equal to 1.1 and less than or equal to 3;

[0019] And / or, along the second direction, a ratio of an extension length of the first notch to an extension length of the first electrode tab is greater than or equal to 2.5 and less than or equal to 5.

[0020] In a possible implementation, the first pole piece unit further has a second notch, the first notch and the second notch are arranged at intervals along the second direction, and the first notch and the second notch are located on the same side of the first current collector, and at least two second notches overlap along the thickness direction of the first current collector to form a second receiving groove;

[0021] Along the second direction, a ratio of an extension length of the first notch to an extension length of the second notch is greater than or equal to 0.4, and greater than or equal to 0.9.

[0022] In a possible implementation, the battery further includes a second pole piece unit, the second pole piece unit and the first pole piece unit have opposite polarities, and the first pole piece unit and the second pole piece unit are stacked;

[0023] The second pole piece unit includes a second current collector, a second active material layer and a third notch, at least two of the third notches overlap in the thickness direction of the first current collector, and the third notches are arranged corresponding to the first notches to jointly define a first receiving groove;

[0024] The second active material layer is arranged on two opposite sides of the second pole piece unit. Along the first direction, the second active material layer has a third side edge on one side close to the first pole ear. The projection of the third side edge on the first pole piece unit is located in the insulating layer.

[0025] In one possible implementation, the second pole piece unit also includes a second pole ear and a fourth notch, the second pole ear is connected to the second current collector, at least two second pole ears are interconnected to form a second pole ear group, at least two fourth notches overlap along the thickness direction of the second current collector, the fourth notch and the second notch are arranged correspondingly to jointly define a second receiving groove, and the second pole ear group is at least partially located in the second receiving groove.

[0026] In a possible implementation, there is a first rounded corner between adjacent sides of the first notch, and the diameter of the first rounded corner is greater than or equal to 1 mm;

[0027] And / or, there is a second rounded corner between adjacent side edges of the fourth notch, and the diameter of the second rounded corner is greater than or equal to 1 mm.

[0028] The battery provided by the present application includes a first pole piece unit, the first pole piece unit includes a first current collector, a first active material layer, a first pole ear and a first notch, the first active material layer includes a first active coating and a second active coating, the first active coating includes a first side edge, and the second active coating includes a second side edge. The first active material layer is set to react with the electrolyte to generate current, the first current collector is set to collect the current generated by the first active material layer, the first pole ear is set to derive the current of the first current collector, at least two first pole ears are connected to each other to form a first pole ear group, so as to improve the charging and discharging efficiency of the battery, and the first notch is set so that after the first pole piece unit is wound or stacked, at least two first notches overlap along the thickness direction of the first current collector to form a first receiving groove, and then the first pole ear group is received in the first receiving groove to avoid the first pole ear group from increasing the invalid volume of the battery, thereby improving the energy density of the battery. By staggering the first side edge and the second side edge along the first direction, the cleaning effect can be ensured and the first current collector can be prevented from being damaged during cleaning.

[0029] In addition to the technical problems solved by the embodiments of the present application described above, the technical features that constitute the technical solutions, and the beneficial effects brought about by the technical features of these technical solutions, other technical problems that can be solved by the battery provided by the present application, other technical features included in the technical solutions, and the beneficial effects brought about by these technical features will be further described in detail in the specific implementation methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0031] Figure 1 A schematic diagram of the structure of a battery provided in an embodiment of the present application;

[0032] Figure 2 A schematic diagram of the structure of a first pole piece unit in a battery provided in an embodiment of the present application;

[0033] Figure 3 for Figure 2 AA section view;

[0034] Figure 4 A schematic structural diagram of a first surface of a first pole piece unit in a battery provided in an embodiment of the present application;

[0035] Figure 5A schematic diagram of the structure of the second surface of the first pole piece unit in the battery provided in an embodiment of the present application;

[0036] Figure 6 A schematic diagram of the structure of the first current collector and the first electrode tab in the battery provided in an embodiment of the present application;

[0037] Figure 7 A schematic diagram of the structure of the second pole piece unit in the battery provided in an embodiment of the present application;

[0038] Figure 8 A schematic diagram of the structure of the first pole piece unit and the second pole piece unit in the battery provided in an embodiment of the present application.

[0039] Description of reference numerals:

[0040] 100-first pole piece unit; 100a-first surface; 100b-second surface; 110-first current collector; 120-first active material layer; 121-first active coating layer; 1211-first side edge; 122-second active coating layer; 1221-second side edge; 1222-first coating area; 1223-second coating area; 130-first pole ear; 140-first notch; 150-insulating layer; 151-first insulating coating layer; 1511-first area; 1512-second area; 152-second insulating coating layer; 160-second notch; 200-first receiving groove; 300-second pole piece unit; 310-second current collector; 320-second active material layer; 321-third side edge; 330-third notch; 340-second pole ear; 350-fourth notch. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme in the embodiment of the present application will be described in more detail below in conjunction with the drawings in the preferred embodiments of the present application. In the drawings, the same or similar reference numerals throughout represent the same or similar parts or parts with the same or similar functions. The described embodiments are part of the embodiments of the present application, not all of the embodiments. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limitations on the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application. The embodiments of the present application are described in detail below in conjunction with the drawings.

[0042] In the description of this application, 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 an indirect connection 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 specific circumstances.

[0043] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are orientations or positional relationships based on the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0044] The terms "first", "second", "third" (if any) in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the application described herein can be implemented in an order other than those illustrated or described herein, for example.

[0045] In addition, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, for example, a process, method, system, product, or display comprising a series of steps or elements is not necessarily limited to those steps or elements explicitly listed, but may include other steps or elements not explicitly listed or inherent to such process, method, product, or display.

[0046] In the related art, a lithium-ion battery mainly includes a battery case and a battery cell. The battery cell and the electrolyte are encapsulated in the battery case. The battery cell may include a positive electrode sheet, a separator and a negative electrode sheet. The positive electrode sheet, the separator and the negative electrode sheet are sequentially stacked and then wound or laminated. Both the positive electrode sheet and the negative electrode sheet may include a foil and an active substance coated on the surface of the foil. During coating, a partial empty foil area is reserved on one side of the electrode sheet in the length direction. After that, part of the active substance is washed off and die-cutting is performed. The foil may form a current collector and a foil pole ear respectively. The active substance covers the current collector. After a plurality of foil pole ears are bent and welded together, a pole ear group may be formed. The pole ear group is connected to an external device through a switching pole ear, thereby drawing out the current of the battery cell.

[0047] Since the tab group needs to occupy part of the space inside the battery casing, the ineffective volume of the battery is increased, thereby reducing the energy density of the battery.

[0048] In view of the above problems, the embodiment of the present application provides a battery, by setting a first notch in the first pole piece unit, so that after the first pole piece unit is wound or stacked to form a battery cell, at least two first notches overlap along the thickness direction of the battery cell, thereby forming a first receiving groove, and then the first pole lug group can be accommodated in the first receiving groove, thereby avoiding the first pole lug group from increasing the invalid volume of the battery, so as to improve the energy density of the battery. At the same time, the first active material layers on the two opposite sides of the first pole piece unit are staggered on the side of the first pole piece unit close to the first pole lug, thereby ensuring that the active material of the first active material layer is cleaned in place and preventing the first current collector from being damaged during cleaning.

[0049] The following is combined with Figure 1 To Attachment Figure 8 The specific implementation of the battery provided in the examples of the present application is described in detail.

[0050] Reference Figures 1 to 6 As shown, the battery provided in the embodiment of the present application includes a first pole piece unit 100, the first pole piece unit 100 includes a first current collector 110, a first active material layer 120, a first pole ear 130 and a first notch 140, the first pole ear 130 is connected to the first current collector 110, at least two first notches 140 overlap along the thickness direction of the first current collector 110 to form a first receiving groove 200, at least two first pole ears 130 are interconnected to form a first pole ear group, and the first pole ear group is at least partially located in the first receiving groove 200.

[0051] The first pole piece unit 100 has a first surface 100a and a second surface 100b opposite to each other. The first active material layer 120 includes a first active coating 121 and a second active coating 122. The first active coating 121 is disposed on the first surface 100a, and the second active coating 122 is disposed on the second surface 100b.

[0052] Along the first direction, the first active coating 121 has a first side 1211 on a side close to the first pole ear 130, and the second active coating 122 has a second side 1221 on a side close to the first pole ear 130. The first side 1211 and the second side 1221 both extend along the second direction, and the first side 1211 and the second side 1221 are staggered along the first direction.

[0053] The first direction can refer to Figure 4 and Figure 5 The X direction in the second direction can refer to Figure 4 and Figure 5 in the Y direction.

[0054] It should be noted that the battery may also include a second pole piece unit 300 and a diaphragm. The polarities of the first pole piece unit 100 and the second pole piece unit 300 are opposite. The first pole piece unit 100, the diaphragm and the second pole piece unit 300 are stacked in sequence and then wound to form a wound battery cell. Alternatively, the first pole piece unit 100, the diaphragm and the second pole piece unit 300 are stacked in sequence and then stacked to form a laminated battery cell. Regardless of whether it is a wound battery cell or a laminated battery cell, the battery cell has at least two folded layers or laminated layers.

[0055] Among them, the first pole piece unit 100 may include a first current collector 110, a first active material layer 120, a first pole ear 130 and a first notch 140. For the convenience of explanation, the polarity of the first pole piece unit 100 is taken as the positive electrode as an example, and the structure of the first pole piece unit 100 is explained in combination with the process flow of the first pole piece unit 100.

[0056] The process flow of the first pole piece unit 100 mainly includes coating, cleaning and die-cutting, etc. First, the first active material is coated on the aluminum foil along the length direction of the aluminum foil to form a first active material layer 120, and when coating, a partial area is reserved on one side of the length direction of the aluminum foil without coating the first active material, that is, the first empty foil area, and then, the preset area on which the first active material layer 120 has been coated is cleaned to clean off the first active material in the preset area, thereby forming a second empty foil area. The first empty foil area and the second empty foil area together constitute an empty foil area, and then, the empty foil area is die-cut, so that the aluminum foil can form a first current collector 110 and a first pole ear 130 respectively, and after die-cutting, a first notch 140 can be formed on the first pole piece unit 100.

[0057] Afterwards, the first pole piece unit 100 can be wound to form a wound battery cell. The battery cell can have multiple folded layers, a part of the folded layers can have the first pole ear 130, and the other part of the folded layers do not have the first pole ear 130. The first notches 140 and the first pole ears 130 are arranged in a one-to-one correspondence. The multiple first pole ears 130 are bent and welded to form a first pole ear group. At the same time, the first notches 140 of each folded layer overlap to form a first receiving groove 200. The first pole ear group can be received in the first receiving groove 200. This can avoid the first pole ear group from increasing the ineffective volume of the battery, thereby effectively improving the energy density of the battery.

[0058] Alternatively, the first pole piece unit 100 can be stacked to form a laminated battery cell, and the battery cell can have multiple stacks, each stack can have a first pole ear 130, the first notch 140 and the first pole ear 130 are arranged in a one-to-one correspondence, and the multiple first pole ears 130 are bent and welded to form a first pole ear group. At the same time, the first notch 140 of each stack overlaps to form a first receiving groove 200, and the first pole ear group can be received in the first receiving groove 200. This can avoid the first pole ear group increasing the ineffective volume of the battery, thereby effectively improving the energy density of the battery.

[0059] It should be understood that during cleaning, the cleaning tool may be a scraper, which is scraped from the outside to the inside along the width direction of the first current collector 110, first cleaning the first surface 100a of the first electrode unit 100, and then cleaning the second surface 100b of the first electrode unit 100. In order to ensure the cleaning effect and prevent the first current collector 110 from being damaged during cleaning, the first active coating 121 on the first surface 100a and the second active coating 122 on the second surface 100b may be staggered for cleaning. When the scraper is cleaning the first surface 100a, when cleaning to the junction of the first current collector 110 and the first pole ear 130, it will continue to move toward the direction of the first current collector 110 until a portion of the first current collector 110 is cleaned and exposed. When the scraper is cleaning the second surface 100b, when cleaning to the junction of the first current collector 110 and the first pole ear 130, it will not continue to move toward the direction of the first current collector 110, and will not expose the first current collector 110. In this way, it can be ensured that the scraper is cleaned in place to fully expose the aluminum foil so as to form a second empty foil area, and at the same time, it can be avoided that the scraper is over-cleaned to prevent the first current collector 110 from being damaged.

[0060] Thus, in the battery finally formed, the first side 1211 and the second side 1221 both extend along the second direction, and the first side 1211 and the second side 1221 are staggered along the first direction. The projection of the first side 1211 along the thickness direction of the first pole piece unit 100 is located on the first current collector 110, and the projection of the second side 1221 along the thickness direction of the first pole piece unit 100 is located on the first pole ear 130. One of the first surface 100a and the second surface 100b exposes a portion of the first current collector 110, and the other does not expose the first current collector 110.

[0061] The battery provided in the embodiment of the present application includes a first pole piece unit 100, the first pole piece unit 100 includes a first current collector 110, a first active material layer 120, a first pole ear 130 and a first notch 140, the first active material layer 120 includes a first active coating 121 and a second active coating 122, the first active coating 121 includes a first side 1211, and the second active coating 122 includes a second side 1221. By setting a first active material layer 120 for reacting with an electrolyte to generate current, by setting a first current collector 110 for collecting the current generated by the first active material layer 120, by setting a first pole ear 130 for deriving the current of the first current collector 110, by connecting at least two first pole ears 130 to form a first pole ear group, the charging and discharging efficiency of the battery is improved, and by setting a first notch 140, after the first pole sheet unit 100 is wound or stacked, at least two first notches 140 overlap along the thickness direction of the first current collector 110 to form a first receiving groove 200, and then the first pole ear group is received in the first receiving groove 200 to avoid the first pole ear group from increasing the invalid volume of the battery, thereby improving the energy density of the battery. By staggering the first side edge 1211 and the second side edge 1221 along the first direction, the cleaning effect can be ensured and the first current collector 110 can be prevented from being damaged during cleaning.

[0062] In some embodiments, along the first direction, the distance between the first side 1211 and the second side 1221 is greater than or equal to 0.5 mm and less than or equal to 2.5 mm.

[0063] If the distance between the first side 1211 and the second side 1221 is less than 0.5 mm, the offset distance between the first side 1211 and the second side 1221 is too small. If the distance between the first side 1211 and the second side 1221 is greater than 2.5 mm, the offset distance between the first side 1211 and the second side 1221 is too large, which may cause excessive cleaning of the first surface 100a, thereby causing damage to the first current collector 110, or causing inadequate cleaning of the second surface 100b, resulting in poor cleaning effect. Therefore, the distance between the first side 1211 and the second side 1221 is set between 0.5 mm and 2.5 mm to improve the cleaning effect.

[0064] Exemplarily, the distance between the first side 1211 and the second side 1221 can be any one of 0.5 mm, 1 mm, 1.5 mm, 2 mm, and 2.5 mm, or can be within any two numerical ranges.

[0065] Reference Figures 2 to 4As shown, in a possible implementation, the first pole piece unit 100 also includes an insulating layer 150, the insulating layer 150 includes a first insulating coating 151, the first insulating coating 151 is arranged on the first surface 100a and is adjacent to the first side 1211, and the projection of the second side 1221 on the first insulating coating 151 is located within the first insulating coating 151.

[0066] It should be noted that after cleaning and before die-cutting, an insulating material can be coated on the side of the second empty foil area away from the first empty foil area, so that a first insulating coating 151 is formed on the first surface 100a, and the first insulating coating 151 is adjacent to the first side 1211. The first insulating coating 151 can improve the safety of the battery.

[0067] Reference Figures 2 to 5 As shown, it is worth mentioning that the second surface 100b may not be provided with the insulating layer 150, or may be provided with the insulating layer 150. In a possible implementation, the insulating layer 150 also includes a second insulating coating 152, and the second insulating coating 152 is provided on the second surface 100b and adjacent to the second side 1221.

[0068] That is to say, the first pole piece unit 100 has two opposite sides provided with an insulating layer 150, and the second surface 100b can be provided with a second insulating coating 152, and the second insulating coating 152 is adjacent to the second side 1221, so that the second insulating coating 152 can improve the safety of the battery.

[0069] When the first pole piece unit 100 is only provided with the first insulating coating 151, if the extension length of the first insulating coating 151 along the first direction is less than 0.1 mm, the first insulating coating 151 has limited effect on improving battery safety, and if the extension length of the first insulating coating 151 along the first direction is greater than 2.4 mm, the first insulating coating 151 occupies a large area, which is not conducive to welding between the plurality of first pole tabs 130, and is not conducive to increasing the area of ​​the first active coating 121. Therefore, in a possible implementation, along the first direction, the extension length of the first insulating coating 151 is greater than or equal to 0.1 mm and less than or equal to 2.4 mm.

[0070] When the first electrode unit 100 is provided with the first insulating coating 151 and the second insulating coating 152 at the same time, along the first direction, the ratio of the extension length of the first insulating coating 151 to the extension length of the second insulating coating 152 is greater than or equal to 1.01 and less than or equal to 4. Such a configuration can ensure that the die-cutting position is on the insulating layer 150 during die-cutting, thereby preventing burrs from being generated during die-cutting, and preventing the first active material layer 120 from extending to the first electrode tab 130, thereby reducing the probability of lithium deposition in the battery.

[0071] For example, along the first direction, the extension length of the first insulating coating 151 may be any one of 0.1 mm, 0.6 mm, 1 mm, 2 mm, and 2.4 mm, or may be within any two numerical ranges. And / or, along the first direction, the ratio of the extension length of the first insulating coating 151 to the extension length of the second insulating coating 152 may be any one of 1.01, 1.5, 2, 3, and 4, or may be within any two numerical ranges.

[0072] In a possible implementation, the first insulating coating 151 includes a first region 1511 and a second region 1512 adjacent to each other, the projection of the first region 1511 on the thickness of the first pole piece unit 100 covers the first current collector 110, and the projection of the second region 1512 on the thickness of the first pole piece unit 100 covers the first pole ear 130. There is a gap between the side of the first region 1511 along the first direction and the side of the first notch 140 along the first direction. That is to say, when coating the insulating material, the insulating material is coated on the side of the second empty foil area away from the first empty foil area. After die-cutting to form the first current collector 110 and the first pole ear 130 respectively, the first insulating coating 151 is located at the junction of the first current collector 110 and the first pole ear 130, that is, the first insulating coating 151 may include a first area 1511 located at the first current collector 110 and a second area 1512 located at the first pole ear 130, and the coating range of the insulating material along the second direction will not be too large, and the two side edges of the first area 1511 along the first direction will not overlap with the side edges of the first notch 140 along the first direction, thereby avoiding the first insulating layer 150 covering a larger area of ​​the first current collector 110, which leads to a reduction in the area of ​​the first active coating 121, thereby improving the energy density of the first pole piece unit 100.

[0073] Reference Figure 4 As shown, in a possible implementation, the second active coating 122 includes a first coating area 1222 and a second coating area 1223 adjacent to each other, the first coating area 1222 is located at the first pole ear 130, and the second coating area 1223 is located at the first current collector 110, and along the first direction, the extension length of the first coating area 1222 is greater than or equal to 0.1 mm and less than or equal to 1 mm.

[0074] That is to say, when only the first insulating coating 151 is provided on the first surface 100a, the second active coating 122 not only covers the first current collector 110, but also covers the first pole ear 130, so that the second active coating 122 includes a first coating area 1222 located at the first pole ear 130 and a second coating area 1223 located at the first current collector 110, wherein the extension length of the first coating area 1222 along the first direction ranges from 0.1 mm to 1 mm, so as to avoid damage to the first current collector 110 due to excessive cleaning, and to avoid the area of ​​the first coating area 1222 being too large to affect the welding between multiple first pole ears 130.

[0075] In some embodiments, the ratio of the thickness of the insulating layer 150 to the thickness of the first active material layer 120 is greater than or equal to 0.1 and less than or equal to 0.9. That is, the insulating layer 150 is thinner than the first active material layer 120. This arrangement can ensure that the insulating layer 150 has a certain thickness to improve the safety of the battery. At the same time, it can prevent the first active material layer 120 and the insulating layer 150 from miscible when the battery generates heat, thereby reducing the battery capacity.

[0076] And / or, along the second direction, the ratio of the extension length of the first notch 140 to the extension length of the insulating layer 150 is greater than or equal to 1.2 and less than or equal to 3.5. In this way, the edge of the first notch 140 can be prevented from exposing the first current collector 110 and causing safety problems such as short circuits in the battery.

[0077] And / or, along the second direction, the ratio of the extension length of the insulating layer 150 to the extension length of the first electrode tab 130 is greater than or equal to 1.1 and less than or equal to 3. This arrangement can ensure that the die-cutting position is on the insulating layer 150 during die-cutting, thereby preventing burrs from being generated during die-cutting, thereby reducing the probability of lithium deposition in the battery.

[0078] And / or, along the second direction, the ratio of the extension length of the first notch 140 to the extension length of the first pole tab 130 is greater than or equal to 2.5 and less than or equal to 5. It should be understood that after the first pole piece unit 100 is wound, it is difficult for the first notches 140 of different folded layers to completely overlap, so a certain tolerance needs to be set, and the extension length of the first notch 140 along the second direction can be appropriately set to be larger than the width of the first pole tab 130, so that the first pole tab group can be completely accommodated in the first receiving groove 200, and when the first pole tabs 130 of different folded layers have different widths, each first pole tab 130 of the first pole tab group can be completely accommodated in the first receiving groove 200.

[0079] Exemplarily, the ratio of the thickness of the insulating layer 150 to the thickness of the first active material layer 120 may be any one of 0.1, 0.2, 0.5, 0.7, and 0.9 or may be within any two numerical ranges. And / or, along the second direction, the ratio of the extension length of the first notch 140 to the extension length of the insulating layer 150 may be any one of 1.2, 1.5, 2, 3, and 3.5 or may be within any two numerical ranges. And / or, along the second direction, the ratio of the extension length of the insulating layer 150 to the extension length of the first pole tab 130 may be any one of 1.1, 1.5, 1.8, 2, and 3 or may be within any two numerical ranges. And / or, along the second direction, the ratio of the extension length of the first notch 140 to the extension length of the first pole tab 130 may be any one of 2.5, 3, 3.5, 4, and 5 or may be within any two numerical ranges.

[0080] Reference Figure 2 As shown, in a possible implementation, the first pole piece unit 100 further has a second notch 160, the first notch 140 and the second notch 160 are spaced apart along the second direction, and the first notch 140 and the second notch 160 are located on the same side of the first current collector 110, and at least two second notches 160 overlap along the thickness direction of the first current collector 110 to form a second receiving groove.

[0081] Along the second direction, the ratio of the extension length of the first notch 140 to the extension length of the second notch 160 is greater than or equal to 0.4, and greater than or equal to 0.9.

[0082] Reference Figure 2 , Figure 7 and Figure 8 As shown, in a possible implementation, the battery further includes a second pole piece unit 300, the second pole piece unit 300 and the first pole piece unit 100 have opposite polarities, and the first pole piece unit 100 and the second pole piece unit 300 are stacked.

[0083] The second pole piece unit 300 includes a second current collector 310, a second active material layer 320 and a third notch 330. At least two third notches 330 overlap in the thickness direction of the first current collector 110. The third notches 330 are arranged corresponding to the first notches 140 to jointly define the first receiving groove 200. The second active material layer 320 is arranged on two opposite sides of the second pole piece unit 300. Along the first direction, the second active material layer 320 has a third side 321 on one side close to the first pole ear 130. The projection of the third side 321 on the first pole piece unit 100 is located inside the insulating layer 150.

[0084] It should be understood that the process flow of the second pole piece unit 300 is similar to that of the first pole piece unit 100, and may also include several steps such as coating, cleaning and die-cutting. During cleaning, unlike the offset cleaning of the two opposite sides of the first pole piece unit 100, there is no obvious difference in the cleaning of the two opposite sides of the second pole piece unit 300. After cleaning, the second active material layers 320 on the two opposite sides of the second pole piece unit 300 form a third side 321. Within the tolerance range allowed, the third side 321 on the two opposite sides of the second pole piece unit 300 can overlap, and the projection of the third side 321 on the insulating layer 150 is located inside the insulating layer 150, so that the content of the second active material in the second active material layer 320 is higher than the content of the first active material in the first active material layer 120, so that the lithium ions have sufficient attachment sites on the second pole piece unit 300, thereby reducing the probability of lithium plating in the battery, thereby improving the safety performance of the battery.

[0085] The projection of the third side 321 on the first insulating coating 151 is located inside the first insulating coating 151 , and / or the projection of the third side 321 on the second insulating coating 152 is located inside the second insulating coating 152 .

[0086] Reference Figure 2 , Figure 7 and Figure 8 As shown, in some embodiments, the second pole piece unit 300 also includes a second pole ear 340 and a fourth notch 350, the second pole ear 340 is connected to the second current collector 310, at least two second pole ears 340 are interconnected to form a second pole ear group, at least two fourth notches 350 overlap along the thickness direction of the second current collector 310, the fourth notch 350 and the second notch 160 are correspondingly arranged to jointly define a second receiving groove, and the second pole ear group is at least partially located in the second receiving groove.

[0087] It should be noted that, compared with a single second pole tab 340, a second pole tab group of multiple second pole tabs 340 connected to each other can improve the charge and discharge efficiency of the battery. For example, the first pole tab group is used to derive the positive current, and the second pole tab group is used to derive the negative current.

[0088] The second receiving groove is used to receive a plurality of second pole tabs 340 to form a second pole tab group, so that the second pole tab group does not increase the ineffective volume of the battery, thereby improving the energy density of the battery.

[0089] Since the width of the first pole ear 130 is smaller than the width of the second pole ear 340, the first receiving groove 200 defined by the multiple first notches 140 is used to accommodate the first pole ear group, and the second receiving groove defined by the multiple second notches 160 is used to accommodate the second pole ear group. Therefore, the extension length of the first notch 140 along the second direction is smaller than the extension length of the second notch 160 along the second direction.

[0090] Exemplarily, along the second direction, the ratio of the extension length of the first notch 140 to the extension length of the second notch 160 can be any one of 0.4, 0.5, 0.7, 0.8, 0.9 or within any two numerical ranges to ensure that the first receiving groove 200 is sufficient to accommodate the first pole lug group and that the second receiving groove is sufficient to accommodate the second pole lug group.

[0091] It is worth mentioning that the diaphragm disposed between the first pole piece unit 100 and the second pole piece unit 300 may also be provided with a fifth notch and a sixth notch, and the first notch 140, the third notch 330 and the fifth notch are correspondingly disposed to jointly define the first receiving groove 200. The second notch 160, the fourth notch 350 and the sixth notch are correspondingly disposed to jointly define the second receiving groove.

[0092] In some embodiments, there is a first rounded corner between adjacent sides of the first notch 140, and the diameter of the first rounded corner is greater than or equal to 1 mm. And / or, there is a second rounded corner between adjacent sides of the fourth notch 350, and the diameter of the second rounded corner is greater than or equal to 1 mm.

[0093] With such a configuration, when the first notch 140 and the second notch 160 are formed by die cutting, the stress generated during die cutting can be reduced, thereby avoiding the stress concentration phenomenon between adjacent sides of the first notch 140 and between adjacent sides of the fourth notch 350, thereby avoiding the subsequent cracking of the first notch 140 and the second notch 160.

[0094] For example, the diameter of the first fillet can be any one of 1 mm, 1.2 mm, 1.5 mm, and 2 mm, or within any two numerical ranges. And / or, the diameter of the second fillet can be any one of 1 mm, 1.1 mm, 1.4 mm, and 1.8 mm, or within any two numerical ranges.

[0095] 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 it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, 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.

Claims

1. A battery, characterized in that: The battery cell comprises a first pole piece unit and a second pole piece unit with opposite polarities, wherein the first pole piece unit and the second pole piece unit are stacked to form a battery cell, wherein the first pole piece unit comprises a first current collector, a first active material layer, a plurality of first pole tabs and a plurality of first notches, wherein the second pole piece unit comprises a plurality of second pole tabs, wherein the first pole tabs are connected to the first current collector, and a plurality of the first notches overlap along the thickness direction of the first current collector to form a first receiving groove, wherein a plurality of the first pole tabs are stacked to form a first pole tab group, and the first pole tab group is at least partially located in the first receiving groove; The first pole piece unit has a first surface and a second surface opposite to each other, the first active material layer includes a first active coating and a second active coating, the first active coating is arranged on the first surface, and the second active coating is arranged on the second surface; The first active coating has a first side edge on a side close to the first pole ear, and the second active coating has a second side edge on a side close to the first pole ear. Both the first side edge and the second side edge extend along a second direction, and the first side edge and the second side edge are staggered along the first direction.

2. The battery according to claim 1, characterized in that Along the first direction, a distance between the first side and the second side is greater than or equal to 0.5 mm and less than or equal to 2.5 mm.

3. The battery according to claim 1 or 2, characterized in that: The first pole piece unit also includes an insulating layer, which includes a first insulating coating. The first insulating coating is arranged on the first surface and is adjacent to the first side edge. The projection of the second side edge in the thickness direction of the first pole piece unit is located in the first insulating coating.

4. The battery according to claim 3, characterized in that The insulating layer further includes a second insulating coating layer, which is disposed on the second surface and adjacent to the second side edge.

5. The battery according to claim 4, characterized in that Along the first direction, a ratio of an extension length of the first insulating coating layer to an extension length of the second insulating coating layer is greater than or equal to 1.01 and less than or equal to 4.

6. The battery according to claim 3, characterized in that The first insulating coating comprises a first region and a second region adjacent to each other, the projection of the first region on the thickness of the first pole piece unit covers the first current collector, and the projection of the second region on the thickness of the first pole piece unit covers the first pole ear; There is a distance between a side edge of the first region along the first direction and a side edge of the first notch along the first direction.

7. The battery according to claim 1 or 2, characterized in that: The second active coating comprises a first coating area and a second coating area adjacent to each other, the first coating area is located at the first electrode ear, and the second coating area is located at the first current collector; Along the first direction, the extension length of the first coating area is greater than or equal to 0.1 mm and less than or equal to 1 mm.

8. The battery according to claim 3, characterized in that The ratio of the thickness of the insulating layer to the thickness of the first active material layer is greater than or equal to 0.1 and less than or equal to 0.9; and / or, along the second direction, a ratio of an extension length of the first notch to an extension length of the insulating layer is greater than or equal to 1.2 and less than or equal to 3.5; and / or, along the second direction, a ratio of an extension length of the insulating layer to an extension length of the first electrode tab is greater than or equal to 1.1 and less than or equal to 3; And / or, along the second direction, a ratio of an extension length of the first notch to an extension length of the first electrode tab is greater than or equal to 2.5 and less than or equal to 5.

9. The battery according to claim 3, characterized in that The first pole piece unit also has a plurality of second notches, the first notches and the second notches are spaced apart along the second direction, and the first notch and the second notch are located on the same side of the first current collector, a plurality of the second notches overlap along the thickness direction of the first current collector to form a second receiving groove, a plurality of the second pole tabs are stacked to form a second pole tab group, and the second pole tab group is at least partially located in the second receiving groove.

10. The battery according to claim 9, characterized in that Along the second direction, a ratio of an extension length of the first notch to an extension length of the second notch is greater than or equal to 0.4, and greater than or equal to 0.

9.

11. The battery according to claim 9, characterized in that The second pole piece unit further includes a second current collector, a second active material layer and a plurality of third notches, wherein the plurality of third notches overlap in the thickness direction of the first current collector, and the third notches are arranged corresponding to the first notches; The second active material layer is arranged on two opposite sides of the second pole piece unit. Along the first direction, the second active material layer has a third side edge on one side close to the first pole ear, and the projection of the third side edge in the thickness direction of the first pole piece unit is located in the insulating layer.

12. The battery according to claim 11, characterized in that The second pole piece unit further includes a plurality of fourth notches, the second pole tab is connected to the second current collector, the plurality of fourth notches overlap along the thickness direction of the second current collector, and the fourth notches and the second notches are arranged correspondingly.

13. The battery according to claim 12, characterized in that There is a first rounded corner between adjacent sides of the first notch, and the diameter of the first rounded corner is greater than or equal to 1 mm; And / or, there is a second rounded corner between adjacent side edges of the fourth notch, and the diameter of the second rounded corner is greater than or equal to 1 mm.

Images