Battery

Abstract

The utility model provides a battery, the battery comprises a first pole piece unit, the first pole piece unit comprises a first current collector, a first active material layer, an insulating layer, a first tab and a first gap, the first pole piece unit has a first surface and a second surface which are opposite to each other, the first active material layer comprises a first active coating and a second active coating, the insulating layer comprises a first insulating coating and a second insulating coating, the first active coating and the first insulating coating are arranged on the first surface, and the second active coating and the second insulating coating are arranged on the second surface; the junction of the first insulating coating and the first active coating is provided with a first edge, the junction of the second insulating coating and the second active coating is provided with a second edge, and the first edge and the second edge are arranged in a staggered mode in the first direction and extend in the second direction. The battery provided by the utility model is relatively high in energy density and safety, 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 in the related art.

[0006] The battery provided in the present application includes a first pole piece unit, the first pole piece unit includes a first current collector, a first active material layer, an insulating layer, a first pole ear and a first notch, the first pole ear is connected to the first current collector, the first pole ear and the first notch are arranged correspondingly, at least two first notches overlap along the thickness direction of the first current collector to form a first receiving groove, at least two first pole ears are connected to each other to form a first pole ear group, and the first pole ear 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 insulating layer includes a first insulating coating and a second insulating coating, the first active coating and the first insulating coating are arranged on the first surface, and the second active coating and the second insulating coating are arranged on the second surface;

[0008] The first insulating coating and the first active coating have a first edge at their junction, the second insulating coating and the second active coating have a second edge at their junction, the first edge and the second edge are staggered along the first direction, and both extend along the second direction.

[0009] In a possible implementation, the junction of the first insulating coating and the first active coating further has a third edge and a fourth edge, and the junction of the second insulating coating and the second active coating further has a fifth edge and a sixth edge;

[0010] The third edge, the fourth edge, the fifth edge, and the sixth edge all extend along the first direction. The third edge and the fifth edge are located on one side of the first tab along the first direction, and the fourth edge and the sixth edge are located on the other side of the first tab along the first direction;

[0011] The third edge and the fifth edge are arranged staggeredly, and / or the fourth edge and the sixth edge are arranged staggeredly.

[0012] In a possible implementation, the projection of the first insulating coating in the thickness direction of the first electrode tab unit covers the projection of the second insulating coating in the thickness direction of the first electrode tab unit.

[0013] In a possible implementation, along the second direction, there is a first spacing between the third edge and the fourth edge, and the ratio of the first spacing to the width of the first tab is greater than or equal to 1.3 and less than or equal to 3;

[0014] and / or, along the second direction, there is a second spacing between the fifth edge and the sixth edge, and the ratio of the second spacing to the width of the first tab is greater than or equal to 1.3 and less than or equal to 3.

[0015] In a possible implementation, the first insulating coating includes a first coating area, and the second insulating coating includes a second coating area. The first coating area simultaneously covers the first tab and the first current collector, and the second coating area simultaneously covers the first tab and the first current collector;

[0016] Along the first direction, the ratio of the extension length of the first coating area to the extension length of the second coating area is greater than or equal to 1.1 and less than or equal to 4.

[0017] In a possible implementation, the first insulating coating further includes a third coating area that covers the first current collector, and the third coating area is located on both sides of the first notch along the first direction;

[0018] The second insulating coating further includes a fourth coating area that covers the first current collector, and the fourth coating area is located on both sides of the first notch along the first direction;

[0019] Along the first direction, the ratio of the extension length of the third coating area to the extension length of the fourth coating area is greater than or equal to 1.1 and less than or equal to 1.5;

[0020] and / or, the ratio of the first spacing to the second spacing is greater than or equal to 1.1 and less than or equal to 1.5.

[0021] In a possible implementation, the two third coating regions are asymmetrically arranged relative to the first tab;

[0022] and / or, the two fourth coating regions are asymmetrically arranged relative to the first tab.

[0023] In a possible implementation, the first insulating coating further includes a fifth coating region that covers the first current collector. The fifth coating region is located on one side of the first notch along the second direction and is adjacent between the first coating region and the third coating region;

[0024] The second insulating coating further includes a sixth coating region that covers the first current collector. The sixth coating region is located on one side of the first notch along the second direction and is adjacent between the second coating region and the fourth coating region.

[0025] In a possible implementation, the battery further includes a second electrode unit with a polarity opposite to that of the first electrode unit. The second electrode unit includes a second current collector and a second notch. At least two second notches overlap along the thickness direction of the second current collector, and the second notch is correspondingly arranged with the first notch.

[0026] In a possible implementation, the ratio of the extension length of the second notch along the second direction to the first spacing is greater than or equal to 0.5 and less than or equal to 0.95;

[0027] and / or, the ratio of the extension length of the second notch along the second direction to the second spacing is greater than or equal to 0.5 and less than or equal to 0.95.

[0028] In a possible implementation, the second notch includes a first side, a second side, and a third side that are adjacent in sequence. The first side and the third side extend along the first direction, and the second side extends along the second direction;

[0029] The projection of the second side in the first electrode unit is located within the insulating layer.

[0030] In a possible implementation, the projection of at least one of the first side and the third side in the first electrode unit is located within the insulating layer;

[0031] Or, the projection of at least one of the first side and the third side in the first electrode unit is located within the first notch.

[0032] In a possible implementation, the first electrode unit further includes a third notch. The first notch and the third notch are arranged at intervals along the second direction. The first notch and the third notch are on the same side of the first current collector. At least two third notches overlap along the thickness direction of the first current collector to form a second receiving groove;

[0033] The second electrode sheet unit further includes at least two second tabs, the second tabs are connected to the second current collector, at least two second tabs are connected to each other to form a second tab group, and at least a part of the second tab group is located in the second receiving groove.

[0034] In a possible implementation, the second electrode sheet unit further has a fourth notch, the fourth notch is correspondingly arranged with the second tab, the second notch and the fourth notch are arranged at intervals in the second direction, at least two fourth notches overlap in the thickness direction of the second current collector, and the fourth notch is correspondingly arranged with the third notch.

[0035] The battery provided by the present application includes a first electrode sheet unit, and the first electrode sheet unit includes a first current collector, a first tab, a first notch, a first active material layer, and an insulating layer. The first current collector is used to collect current, the first tab is provided to lead out the current of the first current collector, at least two first tabs are connected to each other to form a first tab group to improve the charge and discharge efficiency of the battery, and the first notch is provided so that after the first electrode sheet unit is wound or stacked, at least two first notches overlap in the thickness direction of the first current collector to form a first receiving groove, and then the first tab group is received in the first receiving groove to avoid the first tab group increasing the ineffective volume of the battery, thereby improving the energy density of the battery. By staggering the first edge and the second edge in the first direction, the cleaning effect is ensured and the first current collector is prevented from being damaged during cleaning. At the same time, when the first tab is generated by die-cutting, the die-cutting position falls within the insulating layer, thereby reducing the burrs generated during die-cutting, avoiding the burrs and the like from piercing the separator, and improving the safety of the battery.

[0036] In addition to the technical problems solved by the embodiments of the present application described above, the technical features constituting the technical solutions, and the beneficial effects brought by the technical features of these technical solutions, other technical problems that the battery provided by the present application can solve, other technical features included in the technical solutions, and the beneficial effects brought by these technical features will be further described in detail in the specific implementation manner. Description of the Drawings

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0038] Figure 1 It is a schematic structural diagram of the battery provided by the embodiment of the present application;

[0039] Figure 2 It is a schematic structural diagram of the first electrode sheet unit in the battery provided by the embodiment of the present application;

[0040] Figure 3 is Figure 2 the sectional view taken along the A-A direction of

[0041] Figure 4 is the schematic structural view of the first surface of the first pole piece unit in the battery provided by the embodiment of the present application;

[0042] Figure 5 is the schematic structural view of the second surface of the first pole piece unit in the battery provided by the embodiment of the present application;

[0043] Figure 6 is the schematic structural view of the first current collector and the first pole ear in the battery provided by the embodiment of the present application;

[0044] Figure 7 is the schematic view of the projection relationship between the first insulating coating and the second insulating coating in the battery provided by the embodiment of the present application;

[0045] Figure 8 is Figure 4 the sectional view taken along the B-B direction of

[0046] Figure 9 is the schematic structural view of the second pole piece unit in the battery provided by the embodiment of the present application;

[0047] Figure 10 is the schematic structural view of the first pole piece unit and the second pole piece unit in the battery provided by the embodiment of the present application;

[0048] Figure 11 is another schematic structural view of the first pole piece unit and the second pole piece unit in the battery provided by the embodiment of the present application;

[0049] Figure 12 is still another schematic structural view of the first pole piece unit and the second pole piece unit in the battery provided by the embodiment of the present application.

[0050] Explanation of reference numerals:

[0051] 100 - First electrode sheet unit; 100a - First surface; 100b - Second surface; 110 - First current collector; 120 - First tab; 130 - First notch; 140 - Groove; 150 - First active material layer; 150a - First active coating; 150b - Second active coating; 160 - Insulating layer; 160a - First insulating coating; 161a - First coating area; 162a - Third coating area; 163a - Fifth coating area; 164a - First edge; 165a - Third edge; 166a - Fourth edge; 160b - Second insulating coating; 161b - Second coating area; 162b - Fourth coating area; 163b - Sixth coating area; 164b - Second edge; 165b - Fifth edge; 166b - Sixth edge; 170 - Third notch; 200 - First receiving groove; 300 - Second electrode sheet unit; 310 - Second current collector; 320 - Second notch; 321 - First side; 322 - Second side; 323 - Third side; 330 - Second tab; 340 - Fourth notch; 350 - Second active material layer. Detailed implementation manners

[0052] To make the objectives, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be described in more detail below with reference to the accompanying drawings in the preferred embodiments of the present application. In the drawings, the same or similar reference numerals denote the same or similar components or components with the same or similar functions throughout. The described embodiments are some, but not all, of the embodiments of the present application. The embodiments described below by referring to the drawings are exemplary and are intended to explain the present application and should not be construed as a limitation to the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts fall within the scope of protection of the present application. The embodiments of the present application will be described in detail below with reference to the drawings.

[0053] In the description of the present application, it should be noted that unless otherwise clearly defined and limited, the terms "mounted", "connected" and "connected" should be understood in a broad sense. For example, it may be a fixed connection, or an indirect connection through an intermediate medium, or the internal connection or interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0054] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the present application.

[0055] In the description and claims of the present application and the above-mentioned drawings, the terms "first", "second", "third" (if any) are used to distinguish similar objects and do not necessarily have to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present application described herein can be implemented, for example, in an order other than those illustrated or described herein.

[0056] In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or display comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or displays.

[0057] In the related art, a lithium-ion battery mainly includes a battery case and an electrode assembly. The electrode assembly and the electrolyte are encapsulated in the battery case. The electrode assembly may include a positive electrode sheet, a separator, and a negative electrode sheet. After the positive electrode sheet, the separator, and the negative electrode sheet are stacked in sequence, they are wound or laminated. Both the positive electrode sheet and the negative electrode sheet may include a foil and an active material coated on the surface of the foil. During coating, a part of the empty foil area is reserved on one side in the length direction of the electrode sheet, and then part of the active material is washed off, and then die-cutting is performed, so that the foil can form a current collector and a foil tab respectively. The active material covers the current collector, and after multiple foil tabs are bent and welded together, a tab group can be formed. The tab group is connected to an external device through a transfer tab, thereby leading out the current of the electrode assembly.

[0058] Since the tab group needs to occupy a part of the space inside the battery case, it further increases the ineffective volume of the battery, thereby reducing the energy density of the battery.

[0059] In view of the above problems, an embodiment of the present application provides a battery. By providing a first notch in the first electrode sheet unit, after the first electrode sheet unit is wound or laminated to form an electrode core, at least two first notches overlap along the thickness direction of the electrode core, thereby forming a first receiving groove, and then the first tab group can be received in the first receiving groove, so as to avoid the first tab group increasing the ineffective volume of the battery and improve the energy density of the battery. At the same time, by staggering the first edge and the second edge along the first direction, it is ensured that the active material of the first active material layer is cleaned in place and the first current collector is prevented from being damaged during cleaning. At the same time, the burr phenomenon generated by die cutting is reduced.

[0060] The following will describe in detail the specific implementation manners of the battery provided by the embodiment of the present application with reference to the accompanying drawings.

[0061] Refer to Figure 1 In Figure 7 As shown, the battery provided by the present application includes a first electrode sheet unit 100. The first electrode sheet unit 100 includes a first current collector 110, a first tab 120, a first notch 130, and a groove 140. The first tab 120 is connected to the first current collector 110. At least two first notches 130 overlap along the thickness direction of the first current collector 110 to form a first receiving groove 200. At least two first tabs 120 are connected to each other to form a first tab group, and at least a part of the first tab group is located in the first receiving groove 200.

[0062] It should be understood that the battery may further include a second electrode sheet unit 300 and a separator. The polarities of the first electrode sheet unit 100 and the second electrode sheet unit 300 are opposite. After the first electrode sheet unit 100, the separator, and the second electrode sheet unit 300 are laminated in sequence and then wound to form a wound electrode core, or after the first electrode sheet unit 100, the separator, and the second electrode sheet unit 300 are laminated in sequence and then stacked to form a stacked electrode core. Whether it is a wound electrode core or a stacked electrode core, the electrode core has at least two folded layers or stacked layers.

[0063] Specifically, the first electrode sheet unit 100 may include a first current collector 110, a first tab 120, a first notch 130, and a groove 140. The first electrode sheet unit 100 has two opposite surfaces, that is, a first surface 100a and a second surface 100b.

[0064] In addition, refer to Figure 2 And Figure 3As shown, in a possible implementation, the first electrode tab unit 100 further includes a first active material layer 150 and an insulating layer 160. The first active material layer 150 includes a first active coating 150a and a second active coating 150b, and the insulating layer 160 includes a first insulating coating 160a and a second insulating coating 160b. The first active coating 150a and the first insulating coating 160a are disposed on the first surface 100a.

[0065] The second active coating 150b and the second insulating coating 160b are disposed on the second surface 100b. At the junction of the first insulating coating 160a and the first active coating 150a, there is a first edge 164a. At the junction of the second insulating coating 160b and the second active coating 150b, there is a second edge 164b. The first edge 164a and the second edge 164b are arranged staggeredly along a first direction, and both the first edge 164a and the second edge 164b extend along a second direction.

[0066] Wherein, the first direction may be the length direction of the first tab 120, that is, the X direction in the attached drawings for reference, and the second direction may be the width direction of the first tab 120, that is, the Y direction in the attached drawings for reference.

[0067] For the convenience of explanation, an example is given with the polarity of the first electrode tab unit 100 being the positive electrode, and the structure of the first electrode tab unit 100 is described in combination with the manufacturing process of the first electrode tab unit 100.

[0068] The manufacturing process of the first electrode tab unit 100 mainly includes coating, cleaning, die-cutting, etc. Aluminum foil can be used. First, the first active material is coated on the aluminum foil along the length direction of the aluminum foil to form the first active material layer 150. And during coating, a partial area on one side in the length direction of the aluminum foil is reserved without coating the first active material, that is, the first blank foil area. After that, the preset area where the first active material layer 150 has been coated is cleaned to wash away the first active material in this preset area, thereby forming the second blank foil area. The first blank foil area and the second blank foil area together form the blank foil area. Then, the insulating material is coated on the second blank foil area to form the insulating layer 160. Then, the first blank foil area and a part of the insulating layer 160 are die-cut, so that the aluminum foil can respectively form the first current collector 110 and the first tab 120. And after die-cutting, two cuts will be formed on both sides of the first tab 120 along the first direction, and a part of the insulating layer 160 is still reserved on the side of the cut. The first active material layer 150 and the insulating layer 160 define a groove 140. After the first tab 120 is bent later, the blank area formed after the first tab 120 is bent is communicated with the two cuts, so that a first notch 130 can be formed on the first electrode tab unit 100.

[0069] It should be understood that in the finished battery, the bottom wall of the groove 140 is the surface of the insulating layer 160 facing away from the first current collector 110, and the side wall of the groove 140 is the boundary after cleaning the first active material layer 150.

[0070] To ensure the cleaning effect and prevent the first current collector 110 from being damaged during cleaning, different cleaning areas can be set for the first active material on the first surface 100a and the first active material on the second surface 100b. That is to say, during cleaning, the area of the second empty foil area formed on the first surface 100a is larger, while the area of the second empty foil area formed on the second surface 100b is smaller, and the projection of the second empty foil area of the second surface 100b in the thickness direction of the first electrode unit 100 is located within the second empty foil area of the second surface 100b. In this way, the cleaning areas of the first surface 100a and the second surface 100b will not completely overlap, thereby ensuring that the first surface 100a is cleaned in place and avoiding over-cleaning of the second surface 100b, which may cause damage to the first current collector 110, thus facilitating subsequent processes. Moreover, after coating the insulating material and die-cutting, the first edge 164a and the second edge 164b can be arranged to be offset in the first direction. For example, the first edge 164a is closer to the first tab 120 than the second edge 164b. From this, it can be known that the cutting line extending in the second direction during die-cutting will fall within the insulating layer 160. The setting of the insulating layer 160 can prevent the diaphragm from being pierced by burrs generated during die-cutting, thereby improving the safety of the battery.

[0071] After that, the first electrode unit 100 can be wound to form a wound battery cell. The battery cell can have multiple folded layers. Some of the folded layers can have the first tab 120, and some of the folded layers do not have the first tab 120. The first notch 130 and the first tab 120 are arranged in one-to-one correspondence. The multiple first tabs 120 are bent and then welded to form a first tab group. At the same time, the first notches 130 of each folded layer overlap, thereby forming a first receiving groove 200. The first tab group can be received in the first receiving groove 200. This can prevent the first tab group from increasing the ineffective volume of the battery, thereby effectively improving the energy density of the battery.

[0072] Alternatively, the first electrode sheet unit 100 can be stacked to form a laminated battery cell. Different from the wound battery cell that winds the entire first electrode sheet unit 100, before stacking, the first electrode sheet unit 100 needs to be slit first, and then slit into at least two first electrode sheet units 100. After multiple first electrode sheet units 100 are stacked in the thickness direction, the battery cell can have multiple stacked layers. That is, one layer of the first electrode sheet unit 100, one layer of separator, and one layer of the second electrode sheet unit 300 are laminated to form a stacked layer. Each stacked layer can have a first tab 120, and the first notch 130 is arranged in one-to-one correspondence with the first tab 120. Multiple first tabs 120 are bent and welded to form a first tab group. At the same time, the first notches 130 of each stacked layer overlap, and then a first receiving groove 200 is formed. The first tab group can be received in the first receiving groove 200, which can avoid the first tab group increasing the ineffective volume of the battery, thereby effectively improving the energy density of the battery.

[0073] The battery provided by the embodiment of the present application includes a first electrode sheet unit 100, and the first electrode sheet unit 100 includes a first current collector 110, a first tab 120, a first notch 130, a first active material layer 150, and an insulating layer 160. The first current collector 110 is used to collect current, the first tab 120 is provided to lead out the current of the first current collector 110. At least two first tabs 120 are connected to each other to form a first tab group to improve the charge and discharge efficiency of the battery. The first notch 130 is provided so that after the first electrode sheet unit 100 is wound or stacked, at least two first notches 130 overlap in the thickness direction of the first current collector 110 to form a first receiving groove 200, and then the first tab group is received in the first receiving groove 200 to avoid the first tab group increasing the ineffective volume of the battery, thereby improving the energy density of the battery. By staggering the first edge 164a and the second edge 164b in the first direction, the cleaning effect can be ensured and the first current collector 110 can be prevented from being damaged during cleaning. At the same time, the cutting line of die cutting falls within the insulating layer 160 to avoid die cutting generating more burrs and reducing the safety of the battery.

[0074] Refer to Figure 6 And Figure 7 As shown, in a possible implementation manner, there are also a third edge 165a and a fourth edge 166a at the junction of the first insulating coating 160a and the first active coating 150a, and there are also a fifth edge 165b and a sixth edge 166b at the junction of the second insulating coating 160b and the second active coating 150b.

[0075] The third edge 165a, the fourth edge 166a, the fifth edge 165b, and the sixth edge 166b all extend in the first direction. The third edge 165a and the fifth edge 165b are located on one side of the first tab 120 in the first direction, and the fourth edge 166a and the sixth edge 166b are located on the other side of the first tab 120 in the first direction. The third edge 165a and the fifth edge 165b are arranged staggeredly, and / or the fourth edge 166a and the sixth edge 166b are arranged staggeredly.

[0076] That is to say, at the junction of the first insulating coating 160a and the first active coating 150a, there are a third edge 165a and a fourth edge 166a extending in the first direction. The third edge 165a, the first edge 164a, and the fourth edge 166a are adjacent to each other in sequence and surround three sides of the first tab 120. At the junction of the second insulating coating 160b and the second active coating 150b, there are a fifth edge 165b and a sixth edge 166b extending in the first direction. The fifth edge 165b, the second edge 164b, and the sixth edge 166b are adjacent to each other in sequence and surround three sides of the first tab 120. In the above arrangement, the third edge 165a and the fifth edge 165b can be arranged staggeredly, and / or the fourth edge 166a and the sixth edge 166b can be arranged staggeredly to ensure that at least one of the two cutting lines extending in the first direction can fall within the area where the insulating layer 160 is located during die-cutting, that is to say, it can fall within the first insulating coating 160a or within the second insulating coating 160b, thereby reducing the burrs generated during die-cutting.

[0077] In a possible implementation manner, the projection of the first insulating coating 160a in the thickness direction of the first electrode tab unit 100 covers the projection of the second insulating coating 160b in the thickness direction of the first electrode tab unit 100.

[0078] In this arrangement, the area of ​​the first insulating coating 160a is larger, and the area of ​​the second insulating coating 160b is smaller, and the projection relationship between the two is that the first insulating coating 160a covers the second insulating coating 160b. Since the first insulating coating 160a is formed by coating the insulating material on the second empty foil area formed by cleaning the first surface 100a and then die-cutting, and the coating area of ​​the second insulating coating 160b is formed by coating the insulating material on the second empty foil area formed by cleaning the second surface 100b and then die-cutting, it can be seen that before coating the insulating material, the first surface 100 The second empty foil area formed by cleaning surface a is larger than the second empty foil area formed by cleaning surface 100b, so that the first surface 100a and the second surface 100b can be cleaned in an offset manner, thereby ensuring the cleaning effect. At the same time, after the first surface 100a and the second surface 100b are respectively coated with insulating materials, the projection of the first insulating coating 160a in the thickness direction of the first pole piece unit 100 will cover the projection of the second insulating coating 160b in the thickness direction of the first pole piece unit 100. During the subsequent die-cutting, it can be ensured that the cutting line always falls within the insulating layer 160, thereby avoiding the metal foil from generating more burrs.

[0079] It should be understood that, due to process limitations, after the first pole piece unit 100 is wound or stacked, the first pole tabs 120 of each folded or stacked layer overlap in the thickness direction of the first current collector 110, but it is also difficult for each first pole tab 120 to be completely aligned. Therefore, a certain tolerance needs to be set to ensure that the first pole tabs 120 can still be completely accommodated in the first accommodation groove 200 even if they are partially misaligned after winding or stacking. Therefore, in a possible implementation, along the second direction, there is a first spacing between the third edge 165a and the fourth edge 166a, and the ratio of the first spacing to the width of the first pole tab 120 is greater than or equal to 1.3 and less than or equal to 3. And / or, along the second direction, there is a second spacing between the fifth edge 165b and the sixth edge 166b, and the ratio of the second spacing to the width of the first pole tab 120 is greater than or equal to 1.3 and less than or equal to 3.

[0080] The advantage of such a setting is that, firstly, it can make the operable margin larger during die-cutting, thereby making the area that can be cut out of the second empty foil area larger, and then in the first notch 130 formed subsequently, the extension length of the first notch 130 along the width direction of the first pole ear 120 is larger, so as to facilitate the accommodation of the first pole ear group. Secondly, the die-cutting position is still located in the groove 140, and the groove 140 is provided with an insulating layer 160, that is, the die-cutting position is located in the insulating layer 160, thereby preventing burrs from being generated during die-cutting, thereby reducing the probability of lithium deposition in the battery. Finally, such a setting will not cause excessive loss of the first active material of the first active material layer 150.

[0081] Exemplarily, the ratio of the first spacing to the width of the first tab 120 is any one of the values 1.3, 1.5, 2, 2.5, 3 or is within any two of these value ranges. And / or, the ratio of the second spacing to the width of the first tab 120 is greater than or equal to any one of the values 1.3, 1.8, 2.2, 2.4, 3 or is within any two of these value ranges.

[0082] Referring to Figure 4 , Figure 5 and Figure 8 as shown, in some embodiments, the first insulating coating 160a includes a first coating region 161a, the second insulating coating 160b includes a second coating region 161b, the first coating region 161a simultaneously covers the first tab 120 and the first current collector 110, and the second coating region 161b simultaneously covers the first tab 120 and the first current collector 110.

[0083] Along the length direction of the first tab 120, the ratio of the extension length of the first coating region 161a to the extension length of the second coating region 161b is greater than or equal to 1.1 and less than or equal to 4. With such a setting, it can be ensured that during die-cutting, the die-cutting position is simultaneously located in the first coating region 161a and the second coating region 161b, thereby ensuring that the die-cutting position is covered with the insulating layer 160, further preventing burrs from being generated during die-cutting, and further reducing the probability of lithium plating in the battery.

[0084] It should be noted that since the first current collector 110 and the first tab 120 are an integrally formed structure formed by processes such as coating, cleaning, and die-cutting of a metal foil such as aluminum foil, referring to Figure 5 and Figure 6 as shown, taking the side edge of the first notch 130 along the second direction as the demarcation line between the first current collector 110 and the first tab 120, it can be considered that the aluminum foil extending towards the outside of the battery is the first tab 120, and the aluminum foil in the remaining parts is the first current collector 110.

[0085] Referring to Figure 4 , Figure 5 and Figure 8 as shown, in some embodiments, the first insulating coating 160a further includes a third coating region 162a, the third coating region 162a covers the first current collector 110, and the third coating region 162a is located on both sides of the first notch 130 along the length direction of the first tab 120.

[0086] The second insulating coating 160b further includes a fourth coating region 162b, the fourth coating region 162b covers the first current collector 110, and the fourth coating region 162b is located on both sides of the first notch 130 along the length direction of the first tab 120.

[0087] Along the length direction of the first tab 120, the ratio of the extension length of the third coating area 162a to the extension length of the fourth coating area 162b is greater than or equal to 1.1 and less than or equal to 1.5.

[0088] And / or, along the width direction of the first tab 120, the ratio of the distance between the mutually facing sides of the two third coating areas 162a to the distance between the mutually facing sides of the two fourth coating areas 162b is greater than or equal to 1.1 and less than or equal to 1.5.

[0089] It can be understood that the die-cutting position should be located in the insulating layer 160, so as to avoid burrs generated by die-cutting from piercing the separator. After the first notch 130 is formed by die-cutting, at least part of the insulating layer 160 should be retained on both sides of the first notch 130 along the length direction of the first tab 120, that is, the third coating area 162a and the fourth coating area 162b. Among them, along the length direction of the first tab 120, the ratio range of the extension length of the third coating area 162a to the extension length of the fourth coating area 162b can be set between 1.1 and 1.5, and along the width direction of the first tab 120, the ratio range of the distance between the mutually facing sides of the two third coating areas 162a to the distance between the mutually facing sides of the two fourth coating areas 162b can be set between 1.1 and 1.5, that is, the ratio of the first spacing to the second spacing can be set to 1.1 to 1.5. In this way, even when the actual die-cutting position deviates a certain distance relative to the preset die-cutting position along the length direction of the first tab 120 or along the width direction of the first tab 120, the actual die-cutting position is always covered with the insulating layer 160, thereby reducing the short-circuit probability caused by die-cutting burrs piercing the separator.

[0090] Exemplarily, along the length direction of the first tab 120, the ratio of the extension length of the third coating area 162a to the extension length of the fourth coating area 162b can be any one of the values 1.1, 1.2, 1.3, 1.4, 1.5 or within any two value ranges. And / or, along the width direction of the first tab 120, the ratio of the first spacing to the second spacing can be any one of the values 1.1, 1.15, 1.22, 1.38, 1.5 or within any two value ranges.

[0091] In specific implementation, the two third coating areas 162a are asymmetrically arranged relative to the first tab 120, and / or the two fourth coating areas 162b are asymmetrically arranged relative to the first tab 120.

[0092] It should be noted that only when the extension lengths of the two third coating regions 162a along the width direction of the first tab 120 are the same and the two third coating regions 162a are symmetric with respect to the midline position of the first tab 120 in the length direction, can it be considered that the two third coating regions 162a are symmetrically arranged relative to the first tab 120. Similarly, only when the extension lengths of the two fourth coating regions 162b along the width direction of the first tab 120 are the same and the two fourth coating regions 162b are symmetric with respect to the midline position of the first tab 120 in the length direction, can it be considered that the two fourth coating regions 162b are symmetrically arranged relative to the first tab 120. And the two third coating regions 162a are asymmetrically arranged relative to the first tab 120, and / or the two fourth coating regions 162b are asymmetrically arranged relative to the first tab 120. The advantage of such an arrangement is that the process tolerance is larger, the manufacturing process difficulty is reduced, and at the same time, the safety performance of the battery can be ensured.

[0093] Referring to Figure 4 、 Figure 5 As shown, in a possible implementation, the first insulating coating 160a further includes a fifth coating region 163a. The fifth coating region 163a covers the first current collector 110. The fifth coating region 163a is located on one side of the first notch 130 along the width direction of the first tab 120. The fifth coating region 163a is adjacent to the first coating region 161a and the third coating region 162a.

[0094] The second insulating coating 160b further includes a sixth coating region 163b. The sixth coating region 163b covers the first current collector 110. The sixth coating region 163b is located on one side of the first notch 130 along the width direction of the first tab 120. The sixth coating region 163b is adjacent to the second coating region 161b and the fourth coating region 162b.

[0095] In this way, in the first surface 100a of the first electrode sheet unit 100, the two fifth coating regions 163a are adjacent to both sides of the first coating region 161a along the width direction of the first tab 120. The third coating region 162a is adjacent to the side of the fifth coating region 163a away from the first coating region 161a. The first coating region 161a, the third coating region 162a, and the fifth coating region 163a together form a complete first insulating coating 160a. In the second surface 100b of the first electrode sheet unit 100, the two sixth coating regions 163b are adjacent to both sides of the second coating region 161b along the width direction of the first tab 120. The fourth coating region 162b is adjacent to the side of the sixth coating region 163b away from the second coating region 161b. The second coating region 161b, the fourth coating region 162b, and the sixth coating region 163b together form a complete second insulating coating 160b.

[0096] Referring to Figures 9 to 12As shown, in a possible implementation, the battery further includes a second electrode sheet unit 300. The second electrode sheet unit 300 has a polarity opposite to that of the first electrode sheet unit 100. The second electrode sheet unit 300 includes a second current collector 310, second notches 320, and a second active material layer 350. At least two of the second notches 320 overlap in the thickness direction of the second current collector 310. The second notches 320 are correspondingly arranged with the first notches 130. The first notches 130 and the second notches 320 jointly define a first receiving groove 200.

[0097] It should be understood that the manufacturing process of the second electrode sheet unit 300 is similar to that of the first electrode sheet unit 100 and may also include several steps such as coating, cleaning, and die-cutting. Among them, during cleaning, different from the staggered cleaning of the opposite sides of the first electrode sheet unit 100, there is no obvious difference in the cleaning of the opposite sides of the second electrode sheet unit 300. After cleaning, die-cutting is performed to form the second notches 320. The second notches 320 are correspondingly arranged with the first notches 130, and then jointly define the first receiving groove 200, so as to receive the first tab group in the first receiving groove 200.

[0098] In a possible implementation, the ratio of the extension length of the second notch 320 in the second direction to the first spacing is greater than or equal to 0.5 and less than or equal to 0.95, and / or the ratio of the extension length of the second notch 320 in the second direction to the extension length of the second spacing is greater than or equal to 0.5 and less than or equal to 0.95.

[0099] In this way, the content of the second active material in the second active material layer 350 can be made higher than the content of the first active material in the first active material layer 150, so that there are sufficient attachment sites for lithium ions on the second electrode sheet unit 300, thereby reducing the probability of lithium plating in the battery and improving the safety performance of the battery.

[0100] Exemplarily, the ratio of the extension length of the second notch 320 in the second direction to the first spacing can be any value among 0.5, 0.6, 0.7, 0.8, 0.95 or within any two value ranges. And / or the ratio of the extension length of the second notch 320 in the second direction to the extension length of the second spacing can be any value among 0.5, 0.65, 0.7, 0.85, 0.95 or within any two value ranges.

[0101] Refer to Figure 9 And Figure 10As shown, in a possible implementation, the second notch 320 includes a first side 321, a second side 322, and a third side 323 that are adjacent to each other in sequence. The first side 321 and the third side 323 extend along the length direction of the first tab 120, and the second side 322 extends along the width direction of the first tab 120. The projection of the second side 322 on the first electrode sheet unit 100 is located within the insulating layer 160.

[0102] That is to say, after winding or laminating, since the second notch 320 and the first notch 130 are correspondingly arranged, the projection of the first side 321 of the first notch 130 on the first electrode sheet unit 100 should be located within the first insulating coating 160a or the second insulating coating 160b, thereby avoiding direct contact between the first current collector 110 and the second electrode sheet unit 300 and causing a battery short circuit. Thus, the safety performance of the battery can be improved.

[0103] Refer to Figure 9 And Figure 11 As shown, in some embodiments, the projection of at least one of the first side 321 and the third side 323 on the first electrode sheet unit 100 is located within the insulating layer 160.

[0104] In the above arrangement, it can be that the projection of the first side 321 on the first electrode sheet unit 100 is located within the insulating layer 160, or the projection of the third side 323 on the first electrode sheet unit 100 is located within the insulating layer 160, or the projections of both the first side 321 and the third side 323 on the first electrode sheet unit 100 are located within the insulating layer 160. Thus, the insulating layer 160 can block between the separator and the second notch 320, thereby avoiding burrs generated during die-cutting of the second notch 320 from piercing the separator and causing a battery short circuit.

[0105] Refer to Figure 9 And Figure 12 As shown, in other embodiments, the projection of at least one of the first side 321 and the third side 323 on the first electrode sheet unit 100 is located within the first notch 130.

[0106] In the above arrangement, it can be that the projection of the first side 321 on the first electrode sheet unit 100 is located within the first notch 130, or the projection of the third side 323 on the first electrode sheet unit 100 is located within the first notch 130, or the projections of both the first side 321 and the third side 323 on the first electrode sheet unit 100 are located within the first notch 130. Thus, the second active material layer 350 can cover the first active material layer 150, thereby making the content of the second active material greater than that of the first active material, and thus reducing the probability of lithium plating in the battery.

[0107] When the projection of the first side 321 on the first electrode tab unit 100 falls within the insulating layer 160, the projection of the first side 321 may fall within the third coating area 162a corresponding to the first side 321, or within the fourth coating area 162b corresponding to the first side 321. When the projection of the third side 323 on the first electrode tab unit 100 falls within the insulating layer 160, the projection of the third side 323 may fall within the third coating area 162a corresponding to the third side 323, or within the fourth coating area 162b corresponding to the third side 323.

[0108] It is worth mentioning that since the two third coating areas 162a may be asymmetrically arranged relative to the first electrode tab 120, and the two fourth coating areas 162b may also be asymmetrically arranged relative to the first electrode tab 120, therefore, along the second direction, the distance by which the third coating area 162a extends beyond the first side 321 may not be the same as the distance by which the third coating area 162a extends beyond the third side 323, and the distance by which the fourth coating area 162b extends beyond the first side 321 may not be the same as the distance by which the fourth coating area 162b extends beyond the third side 323. In this way, the two sides of the second notch 320 extending along the first direction can always fall within the insulating layer 160 of the first electrode tab unit 100, thereby ensuring the safety performance of the battery.

[0109] In addition, during die-cutting, since the sizes of the cuts formed on both sides in the length direction of the first electrode tab 120 may also be different, therefore, when the projections of the first side 321 and the third side 323 on the first electrode tab unit 100 are located within the first notch 130, along the second direction, the distance by which the first side 321 extends beyond the side of the first notch 130, and the distance by which the third side 323 extends beyond the side of the first notch 130 may be different.

[0110] Refer to Figure 2 And Figure 9 As shown, in a possible implementation, the first electrode tab unit 100 further includes a third notch 170. The first notch 130 and the third notch 170 are arranged at intervals along the width direction of the first electrode tab 120.

[0111] The second electrode tab unit 300 further includes a second electrode tab 330 and a fourth notch 340. The second notch 320 and the fourth notch 340 are arranged at intervals along the width direction of the second electrode tab 330. The fourth notch 340 is correspondingly arranged with the third notch 170. The third notch 170 and the fourth notch 340 jointly define a second receiving groove.

[0112] The second electrode tab 330 is connected to the second current collector 310. At least two second electrode tabs 330 are connected to each other to form a second electrode tab group. At least a part of the second electrode tab group is located within the second receiving groove.

[0113] Thus, by providing the third notch 170 in the first electrode tab unit 100 and the fourth notch 340 in the second electrode tab unit 300, and after the first electrode tab unit 100 and the second electrode tab unit 300 are wound or stacked, the positions of the third notch 170 and the fourth notch 340 correspond to each other, thereby jointly defining the second receiving groove. The second receiving groove can be used to receive a plurality of second tabs 330 connected to form a second tab group, so that the second tab group will not increase the ineffective volume of the battery, thereby improving the energy density of the battery.

[0114] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A battery, characterized in that: The invention comprises a first pole piece unit, wherein the first pole piece unit comprises a first current collector, a first active material layer, an insulating layer, a first pole ear and a first notch, wherein the first pole ear is connected to the first current collector, the first pole ear is arranged corresponding to the first notch, at least two of the first notches overlap along the thickness direction of the first current collector to form a first receiving groove, at least two of the first pole ears are connected to each other to form a first pole ear group, and the first pole ear 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 insulating layer includes a first insulating coating and a second insulating coating, the first active coating and the first insulating coating are arranged on the first surface, and the second active coating and the second insulating coating are arranged on the second surface; The first insulating coating has a first edge at its junction with the first active coating, and the second insulating coating has a second edge at its junction with the second active coating. The first edge and the second edge are staggered along a first direction, and both extend along a second direction.

2. The battery according to claim 1, characterized in that The junction between the first insulating coating and the first active coating further comprises a third edge and a fourth edge, and the junction between the second insulating coating and the second active coating further comprises a fifth edge and a sixth edge; The third edge, the fourth edge, the fifth edge and the sixth edge all extend along the first direction, the third edge and the fifth edge are located on one side of the first pole lug along the first direction, and the fourth edge and the sixth edge are located on the other side of the first pole lug along the first direction; The third edge and the fifth edge are staggered, and / or the fourth edge and the sixth edge are staggered.

3. The battery according to claim 2, characterized in that The projection of the first insulating coating in the thickness direction of the first pole piece unit covers the projection of the second insulating coating in the thickness direction of the first pole piece unit.

4. The battery according to claim 2 or 3, characterized in that: Along the second direction, there is a first distance between the third edge and the fourth edge, and a ratio of the first distance to a width of the first electrode tab is greater than or equal to 1.3 and less than or equal to 3; And / or, along the second direction, there is a second interval between the fifth edge and the sixth edge, and a ratio of the second interval to the width of the first electrode tab is greater than or equal to 1.3 and less than or equal to 3.

5. The battery according to claim 4, characterized in that The first insulating coating includes a first coating area, the second insulating coating includes a second coating area, the first coating area covers the first electrode tab and the first current collector at the same time, and the second coating area covers the first electrode tab and the first current collector at the same time; Along the first direction, a ratio of an extension length of the first coating area to an extension length of the second coating area is greater than or equal to 1.1 and less than or equal to 4.

6. The battery according to claim 5, characterized in that The first insulating coating further includes a third coating area, the third coating area covers the first current collector, and the third coating area is located on both sides of the first notch along the first direction; The second insulating coating layer further includes a fourth coating region, the fourth coating region covers the first current collector, and the fourth coating region is located on both sides of the first notch along the first direction; Along the first direction, the ratio of the extension length of the third coating area to the extension length of the fourth coating area is greater than or equal to 1.1 and less than or equal to 1.5; And / or, a ratio of the first spacing to the second spacing is greater than or equal to 1.1 and less than or equal to 1.

5.

7. The battery according to claim 6, characterized in that The two third coating areas are asymmetrically arranged relative to the first electrode tab; And / or, the two fourth coating areas are arranged asymmetrically relative to the first electrode tab.

8. The battery according to claim 6, characterized in that The first insulating coating further includes a fifth coating area, the fifth coating area covers the first current collector, the fifth coating area is located on one side of the first notch along the second direction, and the fifth coating area is adjacent to the first coating area and the third coating area; The second insulating coating layer further includes a sixth coating region, the sixth coating region covers the first current collector, the sixth coating region is located on one side of the first notch along the second direction, and the sixth coating region is adjacent to the second coating region and the fourth coating region.

9. The battery according to claim 4, characterized in that It also includes a second pole piece unit, which has opposite polarity to the first pole piece unit. The second pole piece unit includes a second current collector and a second notch. At least two of the second notches overlap along the thickness direction of the second current collector. The second notch is arranged corresponding to the first notch.

10. The battery according to claim 9, characterized in that A ratio of an extension length of the second notch along the second direction to the first spacing is greater than or equal to 0.5 and less than or equal to 0.95; And / or, a ratio of an extension length of the second notch along the second direction to the second spacing is greater than or equal to 0.5 and less than or equal to 0.

95.

11. The battery according to claim 9, characterized in that The second notch includes a first side edge, a second side edge and a third side edge which are adjacent to each other in sequence, the first side edge and the third side edge extend along the first direction, and the second side edge extends along the second direction; The projection of the second side on the first pole piece unit is located within the insulating layer.

12. The battery according to claim 11, characterized in that The projection of at least one of the first side and the third side on the first pole piece unit is located within the insulating layer; Alternatively, a projection of at least one of the first side and the third side on the first pole piece unit is located within the first notch.

13. The battery according to claim 9, characterized in that The first pole piece unit further includes a third notch, the first notch and the third notch are arranged at intervals along the second direction, the first notch and the third notch are located on the same side of the first current collector, and at least two of the third notches overlap along the thickness direction of the first current collector to form a second receiving groove; The second pole piece unit further includes a second pole lug, which is connected to the second current collector, and at least two of the second pole lugs are connected to each other to form a second pole lug group, and the second pole lug group is at least partially located in the second receiving groove.

14. The battery according to claim 13, characterized in that The second pole piece unit also has a fourth notch, the second pole ear is arranged corresponding to the fourth notch, the second notch and the fourth notch are arranged at intervals along the second direction, at least two of the fourth notches overlap along the thickness direction of the second current collector, and the fourth notch is arranged corresponding to the third notch.

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