Pole piece assembly, battery and electric equipment

Abstract

The utility model discloses a pole piece assembly, a battery and electric equipment. The pole piece assembly comprises a cathode piece and an anode piece, the cathode piece comprises a cathode current collector and a cathode active layer coated on the cathode current collector, and the cathode active layer is provided with a first hole body. The anode strip comprises an anode current collector and an anode active layer coated on the anode current collector, and the anode active layer is provided with a second hole body. Wherein the volume of the first hole body is larger than that of the second hole body. The scheme can reduce the expansion rate of the battery, prevent the problems of lithium precipitation and the like, and effectively improve the safety performance of the battery.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of battery, especially relates to a pole piece assembly, battery and electric equipment. BACKGROUND

[0002] Lithium ion battery has high energy density, no memory effect, long cycle life, can fast charge and discharge and few self-discharge and other outstanding advantages, is widely used in consumer electronics, electric vehicles and energy storage and other fields. In prior art, affected by material, process and structure and other aspects, lithium ion battery is prone to black spot, lithium precipitation and other adverse phenomena in 3C, 5C, even 10C and other large rate charge and discharge process, seriously affect the safety of battery. SUMMARY

[0003] The utility model discloses a pole piece assembly, battery and electric equipment, which aims to solve the technical problem of poor battery safety performance.

[0004] To achieve the above object, the utility model discloses a pole piece assembly in the first aspect embodiment, comprising:

[0005] The cathode sheet comprises a cathode current collector and a cathode active layer coated on the cathode current collector, and the cathode active layer is provided with a first hole body.

[0006] The anode sheet comprises an anode current collector and an anode active layer coated on the anode current collector, and the anode active layer is provided with a second hole body.

[0007] The volume of the first hole body is greater than the volume of the second hole body.

[0008] In some embodiments, the volume of the first hole body is V1, the volume of the second hole body is V2, and the first hole body and the second hole body satisfy 1.5≤V1 / V2≤2.5.

[0009] In some embodiments, the hole opening area of the first hole body is S1, the hole opening area of the second hole body is S2, the hole depth of the first hole body is H1, and the hole depth of the second hole body is H2; wherein when 0.9≤S1 / S2≤1.1, then 1.5≤H1 / H2≤2.5.

[0010] In some embodiments, the hole depth of the first hole body satisfies 9μm≤H1≤25μm, and the hole depth of the second hole body satisfies 6μm≤H2≤10μm.

[0011] In some embodiments, the first hole body has an orifice area S1, the second hole body has an orifice area S2, the first hole body has a hole depth H1, and the second hole body has a hole depth H2, wherein when 0.9≤H1 / H2≤1.1, then 1.5≤S1 / S2≤2.5.

[0012] In some embodiments, the first hole body has an orifice area S1 satisfying 2.355mm 2 ≤S1≤15.7mm 2 , and the second hole body has an orifice area S2 satisfying 1.57mm 2 ≤S2≤6.28mm 2 .

[0013] In some embodiments, the cathode active layer is provided with a plurality of the first hole bodies, and each of the first hole bodies is arranged at intervals along the length direction of the cathode sheet; and the anode active layer is provided with a plurality of the second hole bodies, and each of the second hole bodies is arranged at intervals along the length direction of the anode sheet.

[0014] In some embodiments, the cathode sheet has a first side edge facing away from the first hole body along the width direction of the cathode sheet, and the minimum distance from the edge of the first hole body to the first side edge is L1; and the cathode sheet has a second side edge facing away from the first hole body along the length direction of the cathode sheet, and the minimum distance from the edge of the first hole body to the second side edge is L2; wherein 1mm≤L1=L2≤5mm.

[0015] and / or,

[0016] The anode sheet has a third side edge facing away from the second hole body along the width direction of the anode sheet, and the minimum distance from the edge of the second hole body to the third side edge is L3; and the anode sheet has a fourth side edge facing away from the second hole body along the length direction of the anode sheet, and the minimum distance from the edge of the second hole body to the fourth side edge is L4; wherein 1mm≤L3=L4≤5mm.

[0017] The utility model discloses a second aspect embodiment proposes a kind of batteries, including the pole piece assembly described in above embodiment.

[0018] The utility model discloses a third aspect embodiment proposes a kind of electric equipment, including the battery described in above embodiment, the battery is used to power supply for the electric equipment.

[0019] Compared with the prior art, the utility model has the beneficial effects including:

[0020] The technical scheme of the utility model discloses, pole piece assembly includes cathode sheet and anode sheet. Cathode sheet includes cathode current collector and the cathode active layer of coating in cathode current collector, and the cathode active layer is equipped with first hole body. Anode sheet includes anode current collector and the anode active layer of coating in anode current collector, and the anode active layer is equipped with second hole body. In prior art, under the influence of material, process and structure etc., lithium ion battery is easy to appear black spot, lithium precipitation etc. in 3C, 5C, even 10C etc. of the process of large rate charge and discharge, seriously influence the safety of battery. The first hole body of this scheme and the second hole body of anode sheet can increase the specific surface area of cathode sheet and anode sheet, provide buffer space for the expansion of active material layer on pole piece after circulation, reduce the expansion rate of battery, effectively improve the safety of battery, and can avoid the local lithium precipitation hidden danger brought by the single hole of cathode and anode sheet. And first hole body and second hole body can provide more paths for lithium ion transmission, reduce ion transmission resistance, reduce battery internal resistance, and provide the possibility for large rate charge and discharge of battery. Further, because the volume of first hole body is greater than the volume of second hole body, that is, the loss of active material of cathode sheet is greater than the loss of active material of anode sheet, so that the anode capacity is slightly greater than the cathode capacity, to prevent lithium precipitation and other problems, and improve the safety performance of battery. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical scheme in the embodiments of the utility model or prior art, the drawings needed to be used in the embodiment or prior art description will be briefly introduced below, and obviously, the drawings in the following description are only some embodiments of the utility model, and other drawings can be obtained according to the structure shown in these drawings without creative labor for those skilled in the art.

[0022] Figure 1 It is the structural schematic diagram of pole piece assembly in an embodiment of the utility model, wherein, cathode sheet, anode sheet and diaphragm are shown.

[0023] Figure 2 It is the schematic diagram of cathode sheet in an embodiment of the utility model, wherein, first hole body is shown.

[0024] Figure 3 It is the schematic diagram of anode sheet in an embodiment of the utility model, wherein, second hole body is shown.

[0025] BRIEF DESCRIPTION OF DRAWINGS

[0026] Pole piece assembly 10;

[0027] Cathode sheet 100;Cathode current collector 110;Cathode active layer 120;First hole body 121;First hole axis 122;First side 130;Second side 140;

[0028] Anode sheet 200; anode current collector 210; anode active layer 220; second hole body 221; second hole axis 222; third side edge 230; fourth side edge 240;

[0029] Diaphragm 20.

[0030] The purposes, functional features and advantages of the utility model will be further described with reference to the drawings in combination with embodiments. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the utility model.

[0032] The first aspect embodiment of the utility model provides a kind of pole piece assembly 10, pole piece assembly 10 is used for battery. Below referring to Figures 1 to 3 The pole piece assembly 10 of the present application embodiment will be introduced. Specifically, pole piece assembly 10 includes cathode sheet 100 and anode sheet 200.

[0033] Referring to Figure 1 And Figure 2 , first introduce cathode sheet 100. In the discharge process, cathode sheet 100 is the positive pole of battery, in the discharge of battery, lithium cobaltate, lithium iron phosphate etc. in cathode sheet 100 (positive pole material) occur reduction reaction, obtain electron. Cathode sheet 100 includes cathode current collector 110 and cathode active layer 120. It can be understood that cathode active layer 120 can be coated on one side or both sides of cathode current collector 110 along its thickness direction. Cathode active layer 120 is provided with first hole body 121. It needs to be explained that first hole body 121 is blind hole. First hole body 121 has first hole axis 122 through its inside. It can be understood that first hole body 121 can be round hole, square hole or polygonal hole, etc., and the present application embodiment is described by taking first hole body 121 as round hole as an example.

[0034] Referring to Figure 1 And Figure 3The anode sheet 200 is introduced below. In the discharging process, the anode sheet 200 is the negative electrode of the battery, and the graphite in the anode sheet 200 (negative electrode material) is oxidized to release electrons. The anode sheet 200 includes an anode current collector 210 and an anode active layer 220. It should be noted that the anode active layer 220 can be coated on one side or both sides of the anode current collector 210 along the thickness direction thereof. The anode active layer 220 is provided with a second hole body 221. It can be understood that the second hole body 221 is a blind hole, and the second hole body 221 has a second hole axis 222 penetrating through the inside thereof. In some embodiments, the shape of the second hole body 221 can be the same as that of the first hole body 121. In other embodiments, the shape of the second hole body 221 can be different from that of the first hole body 121, and the embodiments of the present application are described by taking the case where the shape of the second hole body 221 is the same as that of the first hole body 121 as an example.

[0035] Referring to Figure 1 The relative arrangement of the first hole body 121 and the second hole body 221 is introduced below. In some embodiments, the first hole axis 122 of the first hole body 121 can coincide with the second hole axis 222 of the second hole body 221, that is, the opening position of the first hole body 121 can be arranged in alignment with the opening position of the second hole body 221. In other embodiments, the first hole axis 122 can be arranged in parallel and spaced apart from the second hole axis 222, that is, the opening position of the first hole body 121 can be arranged in misalignment with the opening position of the second hole body 221. The specific arrangement of the first hole body 121 and the second hole body 221 can be determined according to actual conditions. Moreover, the volume of the first hole body 121 can be greater than the volume of the second hole body 221.

[0036] The technical scheme of the utility model discloses, pole piece assembly 10 includes cathode sheet 100 and anode sheet 200.Cathode sheet 100 includes cathode current collector 110 and the cathode active layer 120 that coats in cathode current collector 110, and the cathode active layer 120 is equipped with first hole body 121.Anode sheet 200 includes anode current collector 210 and the anode active layer 220 that coats in anode current collector 210, and the anode active layer 220 is equipped with second hole body 221.In prior art, under the influence of material, process and structure etc., battery is easy to appear black spot, lithium precipitation etc. in 3C, 5C, even 10C etc. big rate charging and discharging process, seriously influence the safety of battery.This scheme is through to cathode sheet 100 and set up first hole body 121 and to anode sheet 200 and set up second hole body 221, can increase the specific surface area of cathode sheet 100 and anode sheet 200, provide buffer space for the expansion of active material layer on pole piece after circulation, reduce battery expansion rate, effectively improve the safety of battery, and can avoid the local lithium precipitation hidden danger brought by the hole of cathode and anode sheet.Massive path is provided for lithium ion transmission by first hole body 121 and second hole body 221, reduces ion transmission resistance, reduces battery internal resistance, provides the possibility for battery big rate charging and discharging.Further, because the volume of first hole body 121 is greater than the volume of second hole body 221, that is, the active material loss of cathode sheet 100 is greater than the active material loss of anode sheet 200, so that the anode capacity is slightly greater than the cathode capacity, prevent lithium precipitation and other problems, improve the safety performance of battery.

[0037] The specific relative size of the first hole body 121 and the second hole body 221 of some embodiments will be introduced below. The volume of the first hole body 121 is V1, that is, the volume of the active material removed from the cathode active layer 120 can be V1. The volume of the second hole body 221 is V2, that is, the volume of the active material removed from the anode active layer 220 can be V2. The first hole body 121 and the second hole body 221 satisfy 1.5≤V1 / V2≤2.5. Exemplarily, V1 / V2 can be 1.5, 1.75, 1.92, 2.15, 2.43 or 2.5, etc. The embodiment of the present application takes V1 / V2 as 1.92 as an example for illustration. When the ratio of V1 / V2 is too small, lithium precipitation phenomenon will occur; when the ratio of V1 / V2 is too large, the capacity of the battery will be affected. The first hole body 121 and the second hole body 221 of the present scheme satisfy 1.5≤V1 / V2≤2.5, that is, the capacity, rate performance, safety performance and active material loss of the battery of the present scheme are balanced, which can effectively improve the performance of the battery.

[0038] Reference Figure 1, the specific relative arrangement between the first hole body 121 and the second hole body 221 is introduced. In some embodiments, the hole opening area of the first hole body 121 of the cathode sheet 100 is S1, and the hole opening area of the second hole body 221 of the anode sheet 200 is S2. The hole depth of the first hole body 121 is H1, and the hole depth of the second hole body 221 is H2. Wherein, when 0.9≤S1 / S2≤1.1, then 1.5≤H1 / H2≤2.5. Exemplarily, S1 / S2 can be 0.9, 0.95, 1, 1.02, 1.05 or 1.1, etc. Exemplarily, H1 / H2 can be 1.5, 1.54, 1.7, 1.85, 1.92, 2, 2.28 or 2.5, etc. The above hole depth ratio can improve the low-temperature discharge performance of the battery under the condition that the hole opening area of the first hole body 121 and the hole opening area of the second hole body 221 are certain, and by increasing the punching depth, the internal specific surface area of the punching channel can be increased, the number of lithium ion intercalation sites can be increased, and the expansion of the active material after circulation can be buffered, ensuring the capacity and performance of the battery.

[0039] Referring to Figure 1 , the specific hole depth setting of the first hole body 121 and the second hole body 221 is introduced. In some embodiments, the hole depth of the first hole body 121 satisfies 9μm≤H1≤25μm. Exemplarily, H1 can be 9μm, 10μm, 13.5μm, 16μm, 18μm, 21.8μm, 24μm or 25μm, etc. The hole depth of the second hole body 221 satisfies 6μm≤H2≤10μm. Exemplarily, H2 can be 6μm, 6.5μm, 7.6μm, 9μm or 10μm, etc. The above setting can ensure that the hole depth of the first hole body 121 and the second hole body 221 is within a reasonable range, and can provide a buffer space for the expansion of the active material after circulation, ensuring the capacity and performance of the battery.

[0040] Referring to Figure 1The specific relative arrangement of the first hole body 121 and the second hole body 221 is introduced as follows. In some embodiments, the hole opening area of the first hole body 121 of the cathode sheet 100 is S1, and the hole opening area of the second hole body 221 of the anode sheet 200 is S2. The hole depth of the first hole body 121 of the cathode sheet 100 is H1, and the hole depth of the second hole body 221 of the anode sheet 200 is H2. Wherein, when 0.9≤H1 / H2≤1.1, then 1.5≤S1 / S2≤2.5. Exemplarily, H1 / H2 can be 0.9, 0.93, 0.98, 1, 1.02, 1.05, 1.08 or 1.1, etc. Exemplarily, S1 / S2 can be 1.5, 1.6, 1.74, 1.9, 2, 2.15, 2.2, 2.4 or 2.5, etc. The above arrangement can balance the battery capacity, rate performance, safety performance and active material loss, etc. under the condition that the hole depth of the first hole body 121 and the hole depth of the second hole body 221 are certain, and effectively improve the battery performance.

[0041] Referring to Figure 1 The specific hole opening size arrangement of the first hole body 121 and the second hole body 221 is introduced as follows. In some embodiments, the hole opening area S1 of the first hole body 121 satisfies 2.355mm 2 ≤S1≤15.7mm 2 . Exemplarily, S1 can be 2.355mm 2 , 3mm 2 , 4.5mm 2 , 6mm 2 , 8.4mm 2 , 10mm 2 , 12.5mm 2 , 14mm 2 , 15mm 2 or 15.7mm 2 , etc. The hole opening area S2 of the second hole body 221 satisfies 1.57mm 2 ≤S2≤6.28mm 2 . Exemplarily, S2 can be 1.57mm 2 , 2mm 2 , 2.5mm 2 , 3.48mm 2 , 4.3mm 2 , 5mm 2 or 6.28mm 2 , etc. The above arrangement can ensure that the hole opening area ratio of the first hole body 121 and the second hole body 221 is within a reasonable range, and can provide buffer space for the expansion of the active material after circulation, and protect the capacity and performance of the battery.

[0042] The specific arrangement of the first hole body 121 and the second hole body 221 is introduced as follows. Referring toFigure 1 And Figure 2 In some embodiments, the cathode active layer 120 is provided with a plurality of first hole bodies 121, each of which can have the same size and shape. Each of the first hole bodies 121 can be arranged at intervals along the length direction of the cathode sheet 100, or arranged at intervals along the width direction of the cathode sheet 100. It should be noted that the interval between two adjacent first hole bodies 121 can be uniform, which can effectively reduce the difficulty of opening each of the first hole bodies 121. In other embodiments, referring to Figure 1 And Figure 3 The anode active layer 220 is provided with a plurality of second hole bodies 221, each of which can have the same size and shape. Each of the second hole bodies 221 can be arranged at intervals along the length direction of the anode sheet 200, or arranged at intervals along the width direction of the anode sheet 200. The interval between two adjacent second hole bodies 221 can be uniform, which can effectively reduce the difficulty of opening each of the second hole bodies 221. It should be noted that each of the first hole axes 122 of each of the first hole bodies 121 can coincide with or be arranged at intervals with each of the second hole axes 222 of each of the second hole bodies 221, i.e., the opening positions of each of the first hole bodies 121 of the cathode sheet 100 can be aligned or arranged at intervals with the opening positions of each of the second hole bodies 221 of the anode sheet 200. The above arrangement can reduce the local lithium precipitation risk caused by separate punching of the cathode and anode sheets 200, and improve the performance of the battery.

[0043] Referring to Figure 2 The specific arrangement of the first hole body 121 relative to the cathode sheet 100 will be described below. In some embodiments, the cathode sheet 100 has a first side edge 130 facing away from the first hole body 121 along the width direction thereof. Referring to Figure 2 The width direction of the cathode sheet 100 can be directed upward and downward, i.e., the first side edge 130 can be the side edge of the upper side of the cathode sheet 100. The minimum distance from the edge of the first hole body 121 to the first side edge 130 is L1. The cathode sheet 100 has a second side edge 140 facing away from the first hole body 121 along the length direction thereof, referring to Figure 2In the orientation, the length direction of the cathode sheet 100 can be directed to the left-right direction, that is, the second side edge 140 can be the side edge of the left side of the cathode sheet 100. The minimum distance from the edge of the first hole body 121 to the second side edge 140 is L2. Wherein, 1mm≤L1=L2≤5mm. Exemplarily, L1 and L2 can each be 1mm, 2.5mm, 3.2mm, 4mm, 4.4mm or 5mm. The first hole body 121 in the present scheme adopts the above setting, which can not only prevent the first hole body 121 from being too close to the side edge of the cathode sheet 100 and thus affecting the structural stability of the cathode sheet 100, but also avoid the first hole body 121 from being too far away from the side edge of the cathode sheet 100 and thus affecting the hole body arrangement density of the cathode sheet 100, that is, the battery performance can be effectively improved, and the safety of the battery is guaranteed.

[0044] Referring to Figure 3 , the arrangement of the second hole body 221 relative to the anode sheet 200 is introduced below. In some embodiments, the anode sheet 200 has a third side edge 230 facing away from the second hole body 221 along the width direction thereof, referring to Figure 3 In the orientation, the width direction of the anode sheet 200 can be directed to the up-down direction, that is, the third side edge 230 can be the side edge of the upper side of the anode sheet 200. The minimum distance from the edge of the second hole body 221 to the third side edge 230 is L3. The anode sheet 200 has a fourth side edge 240 facing away from the second hole body 221 along the length direction thereof, referring to Figure 3 In the orientation, the length direction of the anode sheet 200 can be directed to the left-right direction, that is, the fourth side edge 240 can be the side edge of the left side of the anode sheet 200. The minimum distance from the edge of the second hole body 221 to the fourth side edge 240 is L4. Wherein, 1mm≤L3=L4≤5mm. Exemplarily, L3 and L4 can each be 1mm, 1.4mm, 2.3mm, 3.5mm, 4.6mm or 5mm. The second hole body 221 in the present scheme adopts the above setting, which can not only prevent the second hole body 221 from being too close to the side edge of the anode sheet 200 and thus affecting the structural stability of the anode sheet 200, but also avoid the second hole body 221 from being too far away from the side edge of the anode sheet 200 and thus affecting the hole body arrangement density of the anode sheet 200, that is, the battery performance can be effectively improved, and the safety of the battery is guaranteed.

[0045] The second aspect embodiment of the utility model provides a kind of battery, and battery includes the pole sheet assembly 10 of above-mentioned embodiment.The capacity of the battery, rate performance, safety performance and active material loss etc. are balanced, which can effectively improve the battery performance.It can be understood that diaphragm 20 can be arranged between the cathode sheet 100 and the anode sheet 200 of battery.

[0046] The third aspect of the utility model discloses a kind of electric equipment, and electric equipment includes the battery of above-mentioned embodiment, and battery is used to power supply for electric equipment.It can be understood that electric equipment can be mobile phone, tablet computer, notebook computer, battery toy, power tool or electric vehicle etc., and specific application can be determined according to actual situation.The battery of the present application can guarantee the stability and reliability of electric equipment operation.

[0047] The specific preparation process of the battery of the first embodiment of the application is introduced as follows:

[0048] Cathode sheet 100 preparation: 1) lithium iron phosphate, conductive agent super carbon (Super-P) and binder polyvinylidene fluoride (PVDF) are mixed uniformly according to the mass ratio of 97:1.5:1.5 to prepare lithium ion battery positive electrode slurry with certain viscosity, and the slurry is coated on the current collector aluminum foil, dried, rolled and cut to prepare the cathode sheet 100 with the required size; 2) the prepared cathode sheet 100 is punched by laser, the punching depth H1 is 15 μm, and the hole area S1 of the punching is 6.03 mm 2 . Among them, the distance from the first hole body 121 to the first side edge 130 and the second side edge 140 of the cathode sheet 100 is L1 and L2 respectively. L1 and L2 can both be 3 mm.

[0049] Anode sheet 200 preparation: 1) graphite, CMC (carboxymethyl cellulose) and adhesive are mixed uniformly according to the mass ratio of 97.7:1.1:1.2 to prepare lithium ion battery negative electrode slurry with certain viscosity, and the slurry is coated on copper foil, dried, rolled and cut to prepare the anode sheet 200 with the required size; 2) the prepared anode sheet 200 is punched by laser, the punching depth H2 is 15 μm, and the hole area S2 of the punching is 3.14 mm 2 . Among them, the distance from the second hole body 221 to the third side edge 230 and the fourth side edge 240 of the anode sheet 200 is L3 and L4 respectively. L3 and L4 can both be 3 mm.

[0050] Separator 20: PE-based film is coated with aluminum oxide / PVDF slurry on both sides, dried and cut into strips for standby.

[0051] Electrolyte: lithium hexafluorophosphate (LiPF6) is dissolved in a mixed solvent composed of ethylene carbonate (EC), dimethyl carbonate (DMC) and methyl ethyl carbonate (EMC) (the mass ratio of the three is 1:2:1), to obtain an electrolyte with a concentration of 1 mol / L.

[0052] Preparation of lithium ion battery: the above-mentioned cathode sheet 100, separator 20, anode sheet 200 and electrolyte are made into a soft package battery, and the preparation is completed after baking, liquid injection, standing, formation and two-sealing.

[0053] A second embodiment of the present application prepared another kind of pole piece assembly 10. In the pole piece assembly 10, H1 is 15 μm, H2 is 15 μm. S1 is 3.01 mm 2 , S2 is 1.57 mm 2 .

[0054] A third embodiment of the present application prepared another kind of pole piece assembly 10. In the pole piece assembly 10, H1 is 15 μm, H2 is 15 μm. S1 is 12.06 mm 2 , S2 is 6.28 mm 2 .

[0055] A fourth embodiment of the present application prepared another kind of pole piece assembly 10. In the pole piece assembly 10, H1 is 15 μm, H2 is 15 μm. S1 is 7.85 mm 2 , S2 is 3.14 mm 2 .

[0056] A fifth embodiment of the present application prepared another kind of pole piece assembly 10. In the pole piece assembly 10, H1 is 15 μm, H2 is 15 μm. S1 is 4.71 mm 2 , S2 is 3.14 mm 2 .

[0057] A sixth embodiment of the present application prepared another kind of pole piece assembly 10. In the pole piece assembly 10, H1 is 15 μm, H2 is 7.5 μm. S1 is 3.14 mm 2 , S2 is 3.14 mm 2 .

[0058] A seventh embodiment of the present application prepared another kind of pole piece assembly 10. In the pole piece assembly 10, H1 is 15 μm, H2 is 10 μm. S1 is 3.14 mm 2 , S2 is 3.14 mm 2 .

[0059] An eighth embodiment of the present application prepared another kind of pole piece assembly 10. In the pole piece assembly 10, H1 is 15 μm, H2 is 6 μm. S1 is 3.14 mm 2 , S2 is 3.14 mm 2 .

[0060] A first comparative example of the present application prepared a kind of pole piece assembly 10. In the pole piece assembly 10, H1 is 0 μm, H2 is 0 μm. S1 is 0 mm 2 , S2 is 0 mm 2 , that is, the cathode sheet 100 and the anode sheet 200 are not punched.

[0061] A second comparative example of the present application prepared a pole piece assembly 10. The pole piece assembly 10 in which H1 is 15 μm, H2 is 15 μm. S1 is 6.03 mm 2 , S2 is 0 mm 2 , that is, the cathode sheet 100 is punched, and the anode sheet 200 is not punched.

[0062] A third comparative example of the present application prepared a pole piece assembly 10. The pole piece assembly 10 in which H1 is 15 μm, H2 is 15 μm. S1 is 0 mm 2 , S2 is 3.14 mm 2 .

[0063] A fourth comparative example of the present application prepared a pole piece assembly 10. The pole piece assembly 10 in which H1 is 15 μm, H2 is 15 μm. S1 is 1 mm 2 , S2 is 3.14 mm 2 .

[0064] A fifth comparative example of the present application prepared a pole piece assembly 10. The pole piece assembly 10 in which H1 is 15 μm, H2 is 2 μm. S1 is 1 mm 2 , S2 is 3.14 mm 2 .

[0065] A sixth comparative example of the present application prepared a pole piece assembly 10. The pole piece assembly 10 in which H1 is 15 μm, H2 is 15 μm. S1 is 1 mm 2 , S2 is 3.14 mm 2 .

[0066] Table 1 is the test results of some embodiments and comparative examples of the present application.

[0067]

[0068]

[0069] Table 1

[0070] It should be noted that from Table 1, Example 1, Examples 4-5, Comparative Example 4, when V1 / V2>1.92, the capacity of the battery after 300 cycles is low by 14 mAh, which is mainly due to the loss of the cathode coating leading to a decrease in capacity; when V1 / V2<1.92, although its initial capacity is higher than that of Example 1, it will lead to a large battery resistance and a situation of lithium precipitation due to insufficient anode lithium intercalation space at the hole position after long cycle.

[0071] From Table 1, Examples 1-3, when V1 / V2 is 1.92, S2<3.14 mm 2 , its expansion rate is 2.6% larger than that of Example 1, and when S2>3.14 mm2 After 100 cycles, the capacity of the battery decreased by 33 mAh due to the loss of the cathode material.

[0072] As can be seen from Table 1, Example 1, Comparative Example 1 and Comparative Example 3, the anode sheet 200 is not punched or only the anode coating is punched, which causes lithium precipitation on the surface of the anode sheet 200 under high-rate charging and discharging.

[0073] As can be seen from Table 1, Example 1 and Comparative Example 2, the expansion rate of the battery increases by 5.1% because only the cathode sheet 100 is punched and the anode sheet 200 is not punched.

[0074] As can be seen from Table 1, Example 6-8, Comparative Example 1, Comparative Example 5-6, when H1 / H2<1.92, both Example 7 and Comparative Example 8 have the problem of lithium precipitation, mainly because the anode lithium intercalation space at the position corresponding to the hole is insufficient after long cycle of the battery, which causes the problem.

[0075] As can be seen from Table 1, Example 6-8, Comparative Example 1, Comparative Example 5-6, the punching depth affects the low-temperature performance of the battery, and the greater the H2, the higher the 0.4C discharge capacity retention rate at-10℃, which is mainly because the increase of the punching depth causes the large internal specific surface area of the punching channel, so that the lithium intercalation site is increased, thereby improving the low-temperature performance of the battery. In summary, on the basis of ensuring that the battery does not precipitate lithium under fast charging, Example 6 has small internal resistance, low expansion rate, high capacity and good low-temperature discharge performance, which is a preferred choice.

[0076] It should be noted that if the embodiment of the utility model has directionality indication (such as up, down, left, right, front, back), then the directionality indication is only used to explain the relative position relationship, movement condition and the like between components in a certain specific posture, if the specific posture changes, then the directionality indication also changes accordingly. When the direction reference is introduced in the specific embodiment, if the direction is not specially limited as one-way, then the direction can be one-way or bidirectional (two parallel and opposite directions), and whether it is one-way or bidirectional is based on the realization of the ordinary skill in the art. When the direction reference is bidirectional, it is considered that two different embodiments are introduced at the same time.

[0077] In addition, if the description of "first", "second" and the like is involved in the embodiments of the utility model, the description of "first", "second" and the like is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the same or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can be explicitly or implicitly included at least one of the features. In addition, if "and / or", "and / or" or "and / or" appears throughout the text, it means that the three parallel schemes include "A and / or B", including A scheme, or B scheme, or A and B scheme. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of ordinary skilled in the art, when the combination of technical solutions appears contradictory or cannot be realized, it should be considered that the combination of technical solutions does not exist, nor is it within the scope of the utility model claimed by the utility model.

[0078] The above is only the preferred embodiment of the utility model, and does not limit the patent range of the utility model, and any equivalent structural transformation made by the utility model specification and the attached drawings, or direct / indirect application in other related technical fields under the utility model concept of the utility model is included in the patent protection range of the utility model.

Claims

1. A pole piece assembly characterized by, The cathode sheet comprises a cathode current collector and a cathode active layer coated on the cathode current collector, and the cathode active layer is provided with a first hole body; The anode sheet comprises an anode current collector and an anode active layer coated on the anode current collector, and the anode active layer is provided with a second hole body; The volume of the first hole body is greater than the volume of the second hole body.

2. The electrode sheet assembly of claim 1, wherein the volume of the first hole body is V1 and the volume of the second hole body is V2, and the first hole body and the second hole body satisfy 1.5≤V1 / V2≤2.

5.

3. The electrode sheet assembly of claim 2, wherein the first hole body has a hole opening area S1 and a hole depth H1, and the second hole body has a hole opening area S2 and a hole depth H2, and when 0.9≤S1 / S2≤1.1, 1.5≤H1 / H2≤2.

5.

4. The electrode sheet assembly of claim 3, wherein the hole depth of the first hole body satisfies 9μm≤H1≤25μm, and the hole depth of the second hole body satisfies 6μm≤H2≤10μm.

5. The electrode sheet assembly of claim 2, wherein the first hole body has a hole opening area S1 and a hole depth H1, and the second hole body has a hole opening area S2 and a hole depth H2, and when 0.9≤H1 / H2≤1.1, 1.5≤S1 / S2≤2.

5.

6. The electrode sheet assembly of claim 5, wherein 7. The electrode sheet assembly of claim 1, wherein the cathode active layer is provided with a plurality of the first hole bodies, and each of the first hole bodies is arranged at intervals along the length direction of the cathode sheet; and the anode active layer is provided with a plurality of the second hole bodies, and each of the second hole bodies is arranged at intervals along the length direction of the anode sheet.

8. The electrode sheet assembly of claim 1, wherein the cathode sheet has a first side edge away from the first hole body along the width direction of the cathode sheet, and the minimum distance from the edge of the first hole body to the first side edge is L1, and the cathode sheet has a second side edge away from the first hole body along the length direction of the cathode sheet, and the minimum distance from the edge of the first hole body to the second side edge is L2, and 1mm≤L1=L2≤5mm; and / or the anode sheet has a third side edge away from the second hole body along the width direction of the anode sheet, and the minimum distance from the edge of the second hole body to the third side edge is L3, and the anode sheet has a fourth side edge away from the second hole body along the length direction of the anode sheet, and the minimum distance from the edge of the second hole body to the fourth side edge is L4, and 1mm≤L3=L4≤5mm. The battery of claim 9, wherein the battery is used to power the power consumption device. ​ ​ The orifice area S1 of the first hole body satisfies: 2.355 mm 2 ≤ S1 ≤ 15.7 mm 2 The orifice area S2 of the second hole body satisfies: 1.57 mm 2 ≤ S2 ≤ 6.28 mm 2 . ​ ​ ​ ​ ​ ​ 9. A battery characterized by ​ 10. An electrical device, characterized by ​

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