Pole piece and battery

Abstract

The utility model provides a pole piece and a battery, the pole piece comprises an insulating base material, a first pole piece unit and a second pole piece unit, the first pole piece unit and the second pole piece unit are opposite in polarity, the insulating base material is provided with a first surface, and the first pole piece unit and the second pole piece unit are connected to the first surface; the first pole piece units and the second pole piece units are arranged at intervals along the length direction of the insulating base material; the distance D between one end, close to the second pole piece unit, of the first pole piece unit and one end, close to the first pole piece unit, of the second pole piece unit, the thickness d1 of the first pole piece unit and the thickness d2 of the first pole piece unit meet the condition that D is larger than or equal to 10 (d1 + d2) and smaller than or equal to 30 (d1 + d2). According to the pole piece, the production efficiency, the safety and the energy density of the battery are improved.

Description

Technical Field

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

[0002] Lithium-ion batteries can provide power for electric vehicles, electric trains, electric bicycles, golf carts and other means of transportation to replace traditional energy sources such as gasoline. They are the main direction of new energy development at present, or provide power for electronic devices such as mobile phones and tablets.

[0003] In the prior art, a lithium-ion battery is composed of a shell, an electrolyte, and a battery cell. The battery cell may include a positive electrode sheet, a negative electrode sheet, and a separator. The positive electrode sheet, the separator, and the negative electrode sheet are sequentially stacked and then wound. During the winding process, it is difficult to align the positive electrode sheet and the negative electrode sheet. The production process is complicated and needs to be optimized. As a result, an amphiphilic electrode sheet that integrates the positive electrode sheet and the negative electrode sheet into one is produced, that is, metal foils are arranged on opposite sides of the insulating layer, and then the positive electrode active material and the negative electrode active material are respectively coated on the two metal foils to simultaneously form a positive electrode coating and a negative electrode coating on the amphiphilic electrode sheet, and then the positive electrode coating and the negative electrode coating are cold pressed to ensure that the compaction density of the amphiphilic electrode sheet meets the requirements.

[0004] However, different pressures are required for cold pressing of the positive electrode coating and the negative electrode coating. If the same pressure is used for cold pressing, one of the positive electrode coating and the negative electrode coating may be over-pressurized or under-pressurized. Utility Model Content

[0005] Based on this, the present application provides a pole piece and a battery to solve the deficiencies in the related art.

[0006] In a first aspect, the present application provides a pole piece, comprising an insulating substrate, a first pole piece unit and a second pole piece unit, wherein the first pole piece unit and the second pole piece unit have opposite polarities, the insulating substrate has a first surface, the first pole piece unit and the second pole piece unit are connected to the first surface, and the first pole piece unit and the second pole piece unit are spaced apart along the length direction of the insulating substrate;

[0007] The distance D between one end of the first pole piece unit close to the second pole piece unit and one end of the second pole piece unit close to the first pole piece unit, the thickness d1 of the first pole piece unit and the thickness d2 of the first pole piece unit satisfy:

[0008] 10(d1+d2)≤D≤30(d1+d2).

[0009] In a possible implementation, the electrode provided by the present application, the insulating substrate further has a second surface, the second surface is arranged opposite to the first surface, the first electrode unit and the second electrode unit are connected to the second surface, and the first electrode unit and the second electrode unit are arranged at intervals along the length direction of the insulating substrate;

[0010] The first pole piece unit located on the first surface is arranged correspondingly to the first pole piece unit located on the second surface, and the second pole piece unit located on the first surface is arranged correspondingly to the second pole piece unit located on the second surface.

[0011] In a possible implementation, the electrode provided by the present application comprises an insulating substrate including a first substrate segment, a bending segment, and a second substrate segment connected in sequence along its length direction, and the first substrate segment and the second substrate segment are folded in half along the bending segment;

[0012] The first pole piece unit is connected to the first substrate segment, the second pole piece unit is connected to the second substrate segment, and the projection of the first pole piece unit on the first substrate segment and the projection of the second pole piece unit on the first substrate segment at least partially overlap.

[0013] In a possible implementation, the pole piece provided in the present application has a bending section with a groove, the groove extends along the width direction of the insulating substrate, and the groove is located on the inner side of the bending section.

[0014] In a possible implementation, in the pole piece provided in the present application, the cross-sectional shape of the groove is triangular or semicircular.

[0015] In a possible implementation, the pole piece provided by the present application, the polarity of the first pole piece unit is positive, the polarity of the second pole piece unit is negative, the first pole piece unit includes a first current collector and a first active material layer, the first current collector is connected between the first active material layer and the first substrate segment, the second pole piece unit includes a second current collector and a second active material layer, the second current collector is connected between the second active material layer and the second substrate segment;

[0016] The material of the first current collector includes aluminum, and the material of the second current collector includes copper.

[0017] In a possible implementation, in the pole piece provided by the present application, the width of the first active material layer is less than or equal to the width of the first current collector, and the width of the second active material layer is greater than or equal to the width of the first current collector;

[0018] The width of the first current collector is smaller than the width of the second current collector.

[0019] In a possible implementation, the pole piece provided in the present application has a reinforcing rib on a side of the first current collector facing the first substrate segment, and the reinforcing rib extends along the length direction of the first current collector; and / or the reinforcing rib extends along the width direction of the first current collector.

[0020] In a possible implementation, the pole piece, the first current collector and the second current collector provided in the present application are symmetrically arranged with respect to the midline of the length direction of the insulating substrate.

[0021] In a possible implementation, the pole piece provided in the present application further includes a first pole ear and a second pole ear, wherein the first pole ear and the first current collector are integrally formed, and the second pole ear and the second current collector are integrally formed;

[0022] The first pole tab and the second pole tab are located on one side of the side length direction of the first substrate segment, and the first pole tab and the second pole tab are staggered along the same side length direction of the first substrate segment.

[0023] In a possible implementation, the pole piece provided by the present application, the first current collector and the second current collector are both thermally melt-connected to the insulating substrate;

[0024] The material of the insulating substrate includes at least one of polypropylene, polyester and polyvinyl chloride.

[0025] In a second aspect, the present application provides a battery, comprising a diaphragm and the pole piece provided in the first aspect, wherein the diaphragm is located between a first pole piece unit and a second pole piece unit.

[0026] The pole piece provided in the embodiment of the present application includes an insulating substrate, a first pole piece unit and a second pole piece unit, and the insulating substrate includes a first surface. The first pole piece unit and the second pole piece unit are respectively used to form the positive and negative poles of the pole piece, and the insulating substrate is used to integrate the first pole piece unit and the second pole piece unit, and the first pole piece unit and the second pole piece unit are spaced and arranged on the first surface of the insulating substrate along the length direction of the insulating substrate, so as to use different pressures to cold press the first pole piece unit and the second pole piece unit respectively, thereby preventing one of the first pole piece unit and the second pole piece unit from being over-pressurized and the other from being under-pressurized, and the distance D between one end of the first pole piece unit close to the second pole piece unit and one end of the second pole piece unit close to the first pole piece unit, the thickness d1 of the first pole piece unit, and the thickness d2 of the first pole piece unit satisfy: 10(d1+d2)≤D≤30(d1+d2), thereby increasing the creepage distance between the first pole piece unit and the second pole piece unit, and avoiding excessive energy density loss, thereby improving the safety and energy density of the battery.

[0027] 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 pole pieces and batteries 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

[0028] 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.

[0029] Figure 1 Schematic diagram of the structure of the pole piece provided in the embodiment of the present application Figure 1 ;

[0030] Figure 2 Schematic diagram of the structure of the pole piece provided in the embodiment of the present application Figure 2 ;

[0031] Figure 3 Schematic diagram of the structure of the pole piece provided in the embodiment of the present application Figure 3 ;

[0032] Figure 4 for Figure 1 Schematic diagram of the structure after the pole piece is folded in half;

[0033] Figure 5 for Figure 3 Schematic diagram of the structure after the pole piece is folded in half;

[0034] Figure 6 Schematic diagram of the structure of the pole piece provided in the embodiment of the present application Figure 3 ;

[0035] Figure 7 Schematic diagram of the structure of the pole piece provided in the embodiment of the present application Figure 4 ;

[0036] Figure 8 A schematic diagram of the structure of the first current collector in the pole piece provided in an embodiment of the present application;

[0037] Fig. 9 Schematic diagram of the structure of the battery provided in the embodiment of the present application Figure 1 ;

[0038] Fig.10 Schematic diagram of the structure of the battery provided in the embodiment of the present application Figure 2 .

[0039] Description of reference numerals:

[0040] 10-pole piece;

[0041] 100-insulating substrate; 110-first surface; 120-second surface; 130-first substrate segment; 140-bending segment; 141-groove; 150-second substrate segment; 200-first pole piece unit; 210-first current collector; 211-reinforcement rib; 220-first active material layer; 300-second pole piece unit; 310-second current collector; 320-second active material layer; 400-first pole lug; 500-second pole lug;

[0042] 20- Diaphragm. DETAILED DESCRIPTION

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] In the prior art, a lithium-ion battery is composed of a shell, an electrolyte, and a battery cell. The battery cell may include a positive electrode sheet, a negative electrode sheet, and a separator. The positive electrode sheet, the separator, and the negative electrode sheet are sequentially stacked and then wound. During the winding process, it is difficult to align the positive electrode sheet and the negative electrode sheet. The production process is complicated and needs to be optimized. As a result, an amphiphilic electrode sheet that integrates the positive electrode sheet and the negative electrode sheet into one is produced, that is, metal foils are arranged on opposite sides of the insulating layer, and then the positive electrode active material and the negative electrode active material are respectively coated on the two metal foils to simultaneously form a positive electrode coating and a negative electrode coating on the amphiphilic electrode sheet, and then the positive electrode coating and the negative electrode coating are cold pressed to ensure that the compaction density of the amphiphilic electrode sheet meets the requirements.

[0049] However, different pressures are required for cold pressing of the positive electrode coating and the negative electrode coating. The pressure required for cold pressing of the positive electrode coating is greater, while the pressure required for cold pressing of the negative electrode coating is smaller. If the pressure of the positive electrode coating is used for cold pressing, the negative electrode coating will be over-pressurized. If the pressure of the negative electrode coating is used for cold pressing, the positive electrode coating will be under-pressurized.

[0050] In view of this, the embodiment of the present application provides a pole piece and a battery, by arranging a first pole piece unit and a second pole piece unit with opposite polarities on the same surface of an insulating substrate, the first pole piece unit and the second pole piece unit are arranged at intervals along the length direction of the insulating substrate, so that the two rollers of the rolling device can roll along the width direction of the insulating substrate to compact the first pole piece unit and the second pole piece unit respectively, so that the two rollers can set different pressures according to the compaction density of the first pole piece unit and the second pole piece unit, so as to avoid the first pole piece unit and the second pole piece unit being over-pressurized and the other under-pressurized due to the same pressure of the rollers. In addition, in order to improve the safety and energy density of the battery, the distance D between one end of the first pole piece unit close to the second pole piece unit and one end of the second pole piece unit close to the first pole piece unit, the thickness d1 of the first pole piece unit and the thickness d2 of the first pole piece unit satisfy the following relationship: 10(d1+d2)≤D1≤30(d1+d2), thereby increasing the creepage distance between the first pole piece unit and the second pole piece unit, and avoiding excessive reduction of energy density.

[0051] The specific implementation of the electrode and battery provided in the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0052] Reference Figure 1 and Figure 2 As shown, the pole piece 10 provided in the embodiment of the present application includes an insulating substrate 100, a first pole piece unit 200 and a second pole piece unit 300, the polarities of the first pole piece unit 200 and the second pole piece unit 300 are opposite, the insulating substrate 100 has a first surface 110, the first pole piece unit 200 and the second pole piece unit 300 are connected to the first surface 110, and the first pole piece unit 200 and the second pole piece unit 300 are spaced apart along the length direction of the insulating substrate 100.

[0053] The distance D between one end of the first pole piece unit 200 close to the second pole piece unit 300 and one end of the second pole piece unit 300 close to the first pole piece unit 200, the thickness d1 of the first pole piece unit 200 and the thickness d2 of the first pole piece unit 200 satisfy:

[0054] 10(d1+d2)≤D≤30(d1+d2).

[0055] In the present application, one of the first pole piece unit 200 and the second pole piece unit 300 is a positive electrode, and the other is a negative electrode. The first pole piece unit 200 and the second pole piece unit 300 are used to react with the electrolyte to generate current. The insulating substrate 100 is used to integrate the first pole piece unit 200 and the second pole piece unit 300 into one, thereby forming a bipolar pole piece 10 to solve the alignment problem of the unipolar pole piece in the prior art.

[0056] In the prior art, the positive electrode coating and the negative electrode coating are arranged on two opposite sides of the insulating substrate 100. During the production process, the positive electrode coating and the negative electrode coating on two opposite sides of the insulating substrate 100 need to be cold pressed at the same time. If the same pressure value is used, it will inevitably cause the positive electrode coating to be under-pressurized or the negative electrode coating to be over-pressurized.

[0057] In the pole piece 10 of the embodiment of the present application, the first pole piece unit 200 and the second pole piece unit 300 are simultaneously arranged on the first surface 110 of the pole piece 10, that is, the same surface, and the first pole piece unit 200 and the second pole piece unit 300 are spaced apart along the length direction of the insulating substrate 100. In this way, when the pole piece 10 is cold pressed, the two rollers of the rolling equipment can be spaced apart along the length direction of the insulating substrate 100, and the two rollers can roll along the width direction of the insulating substrate 100, and the pressing depths of the two rollers are different. One roller is used to roll the first pole piece unit 200, and the other roller is used to roll the second pole piece unit 300. In this way, after a cold pressing process, the compaction density of the first pole piece unit 200 and the second pole piece unit 300 can meet the corresponding requirements at the same time, thereby avoiding overpressure and underpressure of one of the first pole piece unit 200 and the second pole piece unit 300 due to the use of the same pressure value.

[0058] It is worth mentioning that, since the first pole piece unit 200 and the second pole piece unit 300 are arranged on the same surface of the pole piece 10, in order to improve the safety of the battery, the distance D between the two opposite ends of the first pole piece unit 200 and the second pole piece unit 300 should not be too small to avoid the insulating substrate 100 between the first pole piece unit 200 and the second pole piece unit 300 being polarized. If D<10(d1+d2), the distance between the first pole piece unit 200 and the second pole piece unit 300 is small, the creepage distance is insufficient, and it is easy to cause safety problems in the battery. In order to improve the energy density of the battery, the distance D between the two opposite ends of the first pole piece unit 200 and the second pole piece unit 300 should not be too large to avoid losing more energy density. If D>30(d1+d2), the distance between the first pole piece unit 200 and the second pole piece unit 300 is large, which will cause the pole piece 10 to lose more energy density.

[0059] Therefore, the distance D between one end of the first pole sheet unit 200 close to the second pole sheet unit 300 and one end of the second pole sheet unit 300 close to the first pole sheet unit 200, the thickness d1 of the first pole sheet unit 200 and the thickness d2 of the first pole sheet unit 200 can satisfy the following relationship: 10(d1+d2)≤D≤30(d1+d2), thereby achieving a balance between the safety and energy density of the battery.

[0060] The distance D between one end of the first pole piece unit 200 close to the second pole piece unit 300 and one end of the second pole piece unit 300 close to the first pole piece unit 200 described in the above embodiment should be understood as the straight-line distance between the opposite ends of the first pole piece unit 200 and the second pole piece unit 300 when the pole piece 10 is unfolded. If the pole piece 10 is folded in half, D is the length of the insulating substrate 100 between the opposite ends of the first pole piece unit 200 and the second pole piece unit 300.

[0061] The electrode 10 provided in the embodiment of the present application includes an insulating substrate 100, a first electrode unit 200 and a second electrode unit 300, and the insulating substrate 100 includes a first surface 110. The first electrode unit 200 and the second electrode unit 300 are respectively used to form the positive electrode and the negative electrode of the electrode 10, and the insulating substrate 100 is used to integrate the first electrode unit 200 and the second electrode unit 300, and the first electrode unit 200 and the second electrode unit 300 are spaced apart on the first surface 110 of the insulating substrate 100 along the length direction of the insulating substrate 100, so as to use different pressures to cold press the first electrode unit 200 and the second electrode unit 300, respectively, thereby preventing the first electrode unit 200 and the second electrode unit from being cold pressed. 300, one of them is overvoltage and the other is undervoltage, and the distance D between one end of the first pole piece unit 200 close to the second pole piece unit 300 and one end of the second pole piece unit 300 close to the first pole piece unit 200, the thickness d1 of the first pole piece unit 200 and the thickness d2 of the first pole piece unit 200 satisfy: 10(d1+d2)≤D≤30(d1+d2), thereby increasing the creepage distance between the first pole piece unit 200 and the second pole piece unit 300, and avoiding excessive loss of energy density, thereby improving the safety and energy density of the battery.

[0062] Reference Figure 1 and Figure 3 As shown, in some embodiments, the insulating substrate 100 also has a second surface 120, the second surface 120 is arranged opposite to the first surface 110, the first pole piece unit 200 and the second pole piece unit 300 are connected to the second surface 120, and the first pole piece unit 200 and the second pole piece unit 300 are arranged at intervals along the length direction of the insulating substrate 100.

[0063] The first pole piece unit 200 located on the first surface 110 is disposed correspondingly to the first pole piece unit 200 located on the second surface 120 , and the second pole piece unit 300 located on the first surface 110 is disposed correspondingly to the second pole piece unit 300 located on the second surface 120 .

[0064] That is to say, the first pole piece unit 200 and the second pole piece unit 300 can be arranged on the first surface 110 at intervals along the length direction of the insulating substrate 100. At the same time, the first pole piece unit 200 and the second pole piece unit 300 can also be arranged on the second surface 120 at intervals along the length direction of the insulating substrate 100. In this way, the first pole piece unit 200 and the second pole piece unit 300 are arranged on two opposite surfaces of the insulating substrate 100, thereby improving the energy density of the pole piece 10.

[0065] In terms of positional relationship, the first pole piece unit 200 and the first pole piece unit 200 are correspondingly arranged on two opposite sides of the insulating substrate 100, and the second pole piece unit 300 and the second pole piece unit 300 are correspondingly arranged on two opposite sides of the insulating substrate 100. The rolling equipment can be provided with four rollers. During rolling, the four rollers can be arranged in pairs on two opposite sides of the insulating substrate 100, and the four rollers are arranged in pairs corresponding to the first pole piece unit 200 and the second pole piece unit 300, wherein two rollers use the same pressure to cold press the first pole piece unit 200, and the other two rollers use the same pressure to cold press the second pole piece unit 300, which can simplify the cold pressing process.

[0066] It can be understood that, whether it is the first surface 110 or the second surface 120, the distance D between one end of the first pole piece unit 200 close to the second pole piece unit 300 and one end of the second pole piece unit 300 close to the first pole piece unit 200, the thickness d1 of the first pole piece unit 200 and the thickness d2 of the first pole piece unit 200 can all satisfy the following relationship: 10(d1+d2)≤D≤30(d1+d2).

[0067] Reference Figure 4 and Figure 5 As shown, in a specific implementation, the insulating substrate 100 includes a first substrate segment 130 , a bending segment 140 and a second substrate segment 150 connected in sequence along its length direction, and the first substrate segment 130 and the second substrate segment 150 are folded along the bending segment 140 .

[0068] The first pole piece unit 200 is connected to the first substrate segment 130 , the second pole piece unit 300 is connected to the second substrate segment 150 , and the projection of the first pole piece unit 200 on the first substrate segment 130 and the projection of the second pole piece unit 300 on the first substrate segment 130 at least partially overlap.

[0069] It should be noted that after the first pole piece unit 200 is connected to the first substrate segment 130 and the second pole piece unit 300 is connected to the second substrate segment 150, the pole piece 10 can be folded in half along the center line of the width direction of the bending segment 140. After folding, the first pole piece unit 200 located on the first surface 110 and the second pole piece unit 300 located on the first surface 110 are located on the inner side of the pole piece 10 and are arranged opposite to each other, and the first pole piece unit 200 located on the second surface 120 and the second pole piece unit 300 located on the second surface 120 are located on the outer side of the pole piece 10.

[0070] Subsequently, the folded electrode sheets 10 can be stacked in sequence along the thickness direction of the electrode sheets 10 to form a battery cell. The electrode sheets 10 provided in the embodiment of the present application can increase the stacking speed, thereby improving the production efficiency of the battery.

[0071] Reference Figure 6 and Figure 7 As shown, in a possible implementation, the bending section 140 has a groove 141, the groove 141 extends along the width direction of the insulating substrate 100, and the groove 141 is located on the inner side of the bending section 140. Such a configuration is conducive to the bending of the bending section 140, so that the first substrate section 130 and the second substrate section 150 are folded along the bending section 140, and after folding, it is conducive to reducing the spacing between the first substrate section 130 and the second substrate section 150 along the thickness direction of the electrode sheet 10, so as to reduce the thickness of the battery.

[0072] The groove 141 may be located in the middle of the bending section 140 , so that the first substrate section 130 and the second substrate section 150 can fold the pole piece 10 in half along the center line of the width direction of the bending section 140 .

[0073] Reference Figure 6 and Figure 7 As shown, in some embodiments, the cross-sectional shape of the groove 141 is triangular or semicircular. Compared with grooves 141 of other shapes, the triangular or semicircular groove 141 is more conducive to folding the pole piece 10.

[0074] Reference Figure 4 As shown, in a specific implementation, the first pole piece unit 200 includes a first current collector 210 and a first active material layer 220, and the first current collector 210 is connected between the first active material layer 220 and the first substrate segment 130. The second pole piece unit 300 includes a second current collector 310 and a second active material layer 320, and the second current collector 310 is connected between the second active material layer 320 and the second substrate segment 150. The material of one of the first current collector 210 and the second current collector 310 includes aluminum, and the material of the other includes copper.

[0075] For example, the first electrode unit 200 is a positive electrode, the second electrode unit 300 is a negative electrode, the first current collector 210 can be an aluminum foil, and the second current collector 310 can be a copper foil. The aluminum foil can better match the active material of the positive electrode, and the copper foil can better match the active material of the negative electrode.

[0076] In a possible implementation, the polarity of the first pole piece unit 200 is positive, the polarity of the second pole piece unit 300 is negative, the width of the first active material layer 220 is less than or equal to the width of the first current collector 210, and the width of the second active material layer 320 is greater than or equal to the width of the first current collector 210. The width of the first current collector 210 is less than the width of the second current collector 310.

[0077] It should be noted that when the polarity of the first pole piece unit 200 is positive and the polarity of the second pole piece unit 300 is negative, because the first active material layer 220 uses positive electrode materials, the material cost is relatively high and the conductivity is relatively poor, the width of the first active material layer 220 can be less than or equal to the width of the first current collector 210, which can reduce the material cost of the first active material layer 220. The second active material layer 320 uses negative electrode materials, which have good conductivity, therefore, the width of the second active material layer 320 can be greater than or equal to the width of the second current collector 310 to improve the conductivity of the pole piece 10.

[0078] In addition, in order to provide lithium ions with sufficient attachment sites on the pole piece 10 and prevent lithium deposition on the pole piece 10, the width of the first current collector 210 may be smaller than the width of the second current collector 310. In this way, the active material of the negative electrode can be more than the active material of the positive electrode, so that lithium ions have sufficient space to embed in the second pole piece unit 300, thereby preventing lithium deposition on the pole piece 10, thereby improving the conductivity and safety performance of the pole piece 10.

[0079] Reference Figure 1 and Figure 8 As shown, in some embodiments, a side of the first current collector 210 facing the first substrate segment 130 is provided with a reinforcing rib 211 , and the reinforcing rib 211 extends along the length direction of the first current collector 210 . And / or, the reinforcing rib 211 extends along the width direction of the first current collector 210 .

[0080] In this way, by arranging reinforcing ribs 211 on the surface of the first current collector 210, the degree of extension of the first current collector 210 during cold pressing can be reduced, thereby improving the safety of the electrode 10. In addition, by arranging the reinforcing ribs 211 on the side of the first current collector 210 facing the first substrate segment 130, the reinforcing ribs 211 can be prevented from affecting the thickness of the first active material layer 220, and at the same time, the connection strength between the first current collector 210 and the first substrate segment 130 can be improved.

[0081] For example, the reinforcing ribs 211 may extend only along the length direction of the first current collector 210, and multiple reinforcing ribs 211 may be spaced apart along the width direction of the first current collector 210; or, the reinforcing ribs 211 may extend only along the width direction of the first current collector 210, and multiple reinforcing ribs 211 may be spaced apart along the length direction of the first current collector 210; or, multiple reinforcing ribs 211 may extend along both the length direction and the width direction of the first current collector 210 to form a criss-cross grid.

[0082] Since the edge of the first current collector 210 in the width direction is spaced from the edge of the insulating substrate 100 in the width direction, and the edge of the second current collector 310 in the width direction is also spaced from the edge of the insulating substrate 100 in the width direction, in a possible implementation, the first current collector 210 and the second current collector 310 are both symmetrically arranged relative to the midline of the length direction of the insulating substrate 100. Such an arrangement can improve the tolerance of the pole piece 10 during coating and the tolerance of the pole piece 10 during lamination.

[0083] Reference Figure 2 As shown, in a possible implementation, the pole piece 10 provided in the embodiment of the present application further includes a first pole tab 400 and a second pole tab 500, the first pole tab 400 and the first current collector 210 are integrally formed, and the second pole tab 500 and the second current collector 310 are integrally formed. The first pole tab 400 and the second pole tab 500 are located on one side of the side length direction of the first substrate segment 130, and the first pole tab 400 and the second pole tab 500 are staggered along the same side length direction of the first substrate segment 130.

[0084] For example, the first pole tab 400 and the second pole tab 500 are located on one side of the first substrate segment 130 in the width direction, and the first pole tab 400 and the second pole tab 500 are staggered along the width direction of the first substrate segment 130. Alternatively, the first pole tab 400 and the second pole tab 500 are located on one side of the first substrate segment 130 in the length direction, and the first pole tab 400 and the second pole tab 500 are staggered along the length direction of the first substrate segment 130.

[0085] In this way, the first pole ear 400 can draw out the current of the first pole piece unit 200, and the second pole ear 500 can draw out the current of the second pole piece unit 300. After multiple pole pieces 10 are stacked, in order to facilitate the connection of the first pole ear 400 of each first pole piece unit 200, and in order to facilitate the connection of the second pole ear 500 of each second pole piece unit 300, the first pole ear 400 and the second pole ear 500 can be staggered, and the contact between the first pole ear 400 and the second pole ear 500 can be avoided to cause a short circuit in the battery.

[0086] In some embodiments, the first current collector 210 and the second current collector 310 are both thermally melt-connected to the insulating substrate 100 , wherein the material of the insulating substrate 100 includes at least one of polypropylene, polyester, and polyvinyl chloride.

[0087] In this way, polypropylene, polyester and polyvinyl chloride can all produce good adhesion after hot melting, so that the first current collector 210 can be directly bonded to the first substrate segment 130, and the second current collector 310 can be directly bonded to the second substrate segment 150, without the need to set an additional bonding layer between the first current collector 210 and the first substrate segment 130, and between the second current collector 310 and the second substrate segment 150, thereby simplifying the production process of the pole piece 10.

[0088] In addition, refer to Fig. 9 and Fig.10 As shown, an embodiment of the present application further provides a battery, comprising a diaphragm 20 and the pole piece 10 provided in the above embodiment, wherein the diaphragm 20 is located between the first pole piece unit 200 and the second pole piece unit 300 .

[0089] That is, after the pole piece 10 is folded in half, the first pole piece unit 200 and the second pole piece unit 300 are arranged on opposite sides of the diaphragm 20, and the diaphragm 20 is used to isolate the positive electrode and the negative electrode of the pole piece 10. The battery may include a plurality of pole pieces 10, which are stacked in sequence along the thickness direction of the pole piece 10 after being folded in half, and the diaphragm 20 is sandwiched in the pole piece 10 and between two adjacent pole pieces 10, thereby forming a stacked battery cell.

[0090] 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 pole piece, characterized in that: The method comprises an insulating substrate, a first pole piece unit and a second pole piece unit, wherein the first pole piece unit and the second pole piece unit have opposite polarities, the insulating substrate has a first surface, the first pole piece unit and the second pole piece unit are connected to the first surface, and the first pole piece unit and the second pole piece unit are spaced apart along the length direction of the insulating substrate; The distance D between one end of the first pole piece unit close to the second pole piece unit and one end of the second pole piece unit close to the first pole piece unit, the thickness d1 of the first pole piece unit and the thickness d2 of the first pole piece unit satisfy: 10(d1+d2)≤D≤30(d1+d2).

2. The pole piece according to claim 1, characterized in that: The insulating substrate further has a second surface, the second surface is arranged opposite to the first surface, the first pole piece unit and the second pole piece unit are connected to the second surface, and the first pole piece unit and the second pole piece unit are arranged at intervals along the length direction of the insulating substrate; The first pole piece unit located on the first surface is arranged correspondingly to the first pole piece unit located on the second surface, and the second pole piece unit located on the first surface is arranged correspondingly to the second pole piece unit located on the second surface.

3. The pole piece according to claim 1 or 2, characterized in that: The insulating substrate comprises a first substrate segment, a bending segment and a second substrate segment connected in sequence along its length direction, and the first substrate segment and the second substrate segment are folded in half along the bending segment; The first pole piece unit is connected to the first substrate segment, the second pole piece unit is connected to the second substrate segment, and a projection of the first pole piece unit on the first substrate segment and a projection of the second pole piece unit on the first substrate segment at least partially overlap.

4. The pole piece according to claim 3, characterized in that: The bending section has a groove, the groove extends along the width direction of the insulating substrate, and the groove is located at the inner side of the bending section.

5. The pole piece according to claim 4, characterized in that: The cross-sectional shape of the groove is triangular or semicircular.

6. The pole piece according to claim 3, characterized in that: The polarity of the first pole piece unit is positive, the polarity of the second pole piece unit is negative, the first pole piece unit includes a first current collector and a first active material layer, the first current collector is connected between the first active material layer and the first substrate segment, the second pole piece unit includes a second current collector and a second active material layer, the second current collector is connected between the second active material layer and the second substrate segment; The material of the first current collector includes aluminum, and the material of the second current collector includes copper.

7. The pole piece according to claim 6, characterized in that: The width of the first active material layer is less than or equal to the width of the first current collector, and the width of the second active material layer is greater than or equal to the width of the first current collector; The width of the first current collector is smaller than the width of the second current collector.

8. The pole piece according to claim 6, characterized in that: A reinforcing rib is provided on a side of the first current collector facing the first substrate segment, and the reinforcing rib extends along the length direction of the first current collector; and / or the reinforcing rib extends along the width direction of the first current collector.

9. The pole piece according to claim 6, characterized in that: The first current collector and the second current collector are both symmetrically arranged relative to a midline of a length direction of the insulating substrate.

10. The pole piece according to claim 6, characterized in that: Also includes a first pole ear and a second pole ear, wherein the first pole ear and the first current collector are integrally formed, and the second pole ear and the second current collector are integrally formed; The first pole tab and the second pole tab are located on one side of the side length direction of the first substrate segment, and the first pole tab and the second pole tab are staggered along the same side length direction of the first substrate segment.

11. The pole piece according to claim 6, characterized in that: The first current collector and the second current collector are both thermally melt-connected to the insulating substrate.

12. A battery, characterized in that: It comprises a diaphragm and a pole piece as described in any one of claims 1 to 11, wherein the diaphragm is located between the first pole piece unit and the second pole piece unit.

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