CN117727861A

CN117727861A - Pole piece and battery cell

Info

Publication number: CN117727861A
Application number: CN202311752459.2A
Authority: CN
Inventors: 曹方博; 刘跃争; 侯艳妮; 付西超; 谢继春
Original assignee: Zhuhai Cosmx Battery Co Ltd
Current assignee: Zhuhai Cosmx Battery Co Ltd
Priority date: 2023-12-19
Filing date: 2023-12-19
Publication date: 2024-03-19

Abstract

The application provides a pole piece and electric core, including the electric current body and set up in the active material layer of electric current body at least one side surface, first recess and second recess have been seted up to one side that the electric current body was kept away from to the active material layer, the degree of depth of first recess and second recess is all less than the thickness of active material layer, the electric current body has along the relative first side of first direction and second side and along the relative third side of second direction and fourth side, the first recess extends along the first direction that the directional second side of first side formed, the second recess extends along the second direction that third side and fourth side formed, the quantity of second recess is greater than the quantity of first recess. The number of first grooves in the first direction is set relatively small because the first grooves may limit the horizontal diffusion of lithium ions, thereby reducing the influence on the diffusion of lithium ions. The diffusion direction of lithium ions is perpendicular to the surface of the current collector, and lithium ions are more easily intercalated and deintercalated in the active material layer by increasing the number of grooves along the second groove.

Description

Pole piece and battery cell

Technical Field

The application relates to the technical field of batteries, in particular to a pole piece and an electric core.

Background

Lithium ion batteries have many advantages, and become a major source of power for consumer electronics and electric vehicles. With the increasing demands of people, lithium ion batteries gradually develop into fast charge, long service life, high energy density and high safety. In order to improve the energy density of the lithium ion battery, the battery pole piece often has larger compacted density and thickness, which increases the transmission resistance of lithium ions in the active material while increasing the battery energy density, and which often increases the infiltration difficulty of the electrolyte.

Disclosure of Invention

In view of the above, the application provides a pole piece, which solves the problems of high transmission resistance of lithium ions in an active material and high infiltration difficulty of electrolyte in a battery. The application also provides an electric core comprising the pole piece.

In order to achieve the above purpose, the present application provides the following technical solutions:

the utility model provides a pole piece, includes the electric current collector and set up in the active material layer of electric current collector at least one side surface, first recess and second recess have been seted up to one side that the active material layer kept away from the electric current collector, first recess with the degree of depth of second recess is all less than the thickness of active material layer, wherein:

the current collector has first and second sides opposite in a first direction and third and fourth sides opposite in a second direction, the first grooves extending in the first direction formed by the first sides pointing toward the second side, the second grooves extending in the second direction formed by the third and fourth sides, the number of the second grooves being greater than the number of the first grooves.

Optionally, the first groove and the second groove are each provided with a plurality of grooves.

Optionally, the distance between any adjacent second grooves is smaller than the distance between any adjacent first grooves.

Optionally, a plurality of the first grooves are arranged at equal intervals, and the distance between adjacent first grooves is L ₁ ，5mm≤L ₁ Less than or equal to 25mm; and/or the number of the groups of groups,

a plurality of second grooves are arranged at equal intervals, and the distance between adjacent second grooves is L ₂ ，0.5mm≤L ₂ ≤4mm。

Optionally, the first groove and the second groove intersect.

Optionally, the width W of the first groove ₁ Width W of the second groove ₂ The width of the intersection position of the first groove and the second groove is W ₃ Wherein W is ₁ 、W ₂ W and W ₃ The method meets the following conditions: w (W) ₁ ＜W ₂ ＜W ₃ The method comprises the steps of carrying out a first treatment on the surface of the And/or the number of the groups of groups,

depth H of the first groove ₁ Depth H of the second groove ₂ The depth of the intersection position of the first groove and the second groove is H ₃ Wherein H is ₁ 、H ₂ H and H ₃ The method meets the following conditions: h ₁ ＜H ₂ ＜H ₃ ＜H ₁ +H ₂ 。

Optionally, the pole piece has the first edge of connection utmost point ear, the edge that the pole piece deviates from the first edge is the second edge, the acute angle contained angle of first direction and first edge is a, the second direction with the acute angle contained angle in the first edge is b, and wherein a and b satisfy: a is more than or equal to 0 degree and less than or equal to 10 degrees, and/or b is more than or equal to 80 degrees and less than or equal to 90 degrees.

Optionally, the pole piece includes an extension extending from the current collector, the pole piece includes a first edge near the extension and a second edge far away from the extension, and a distance between the first groove near the first edge and the first edge is T ₁ The distance between the first groove near the second edge and the second edge is B ₁ The distance between the end of the second groove close to the first edge and the first edge is T ₂ The distance between the end of the second groove close to the second edge and the second edge is B ₂ Wherein T is ₁ 、B ₁ 、T ₂ B (B) ₂ The method meets the following conditions: t (T) ₁ Not less than 3mm, and/or B ₁ Not less than 2.5mm, and/or T ₂ 1.2mm or more, and/orB ₂ ≥0.7mm。

Optionally, the pole piece includes a coating area for coating the active material layer and a hollow foil area located at one side of the coating area, the tab is located on the hollow foil area, the pole piece has a first edge connected with the tab, the edge of the pole piece facing away from the first edge is a second edge, in the first direction, the active material layer has a third edge close to the hollow foil area of the pole piece and a fourth edge far from the hollow foil area, and the distance between the first groove close to the first edge and the first edge is T ₅ The distance between the first groove and the second edge near the second edge is B ₅ The distance between the end of the second groove close to the first edge and the first edge is T ₆ The distance between the end of the second groove close to the second edge and the second edge is B ₆ The distance between the end of the second groove close to the third edge and the third edge is S ₁ The distance between the end of the second groove close to the fourth edge and the fourth edge is S2, wherein T is ₅ 、B ₅ 、T ₆ 、B ₆ 、S ₁ S and S ₂ The method meets the following conditions: t (T) ₅ Not less than 3mm, and/or B ₅ Not less than 3mm, and/or T ₆ 0.7mm or more, and/or B ₆ 0.7mm or more, and/or S ₁ 0.1mm or more, and/or S ₂ ≥0mm。

Optionally, a third groove is further formed in a side, far away from the current collector, of the active material layer, the current collector is provided with a fifth side and a sixth side, which are opposite along a third direction, the third groove extends along a third direction formed by pointing the fifth side to the sixth side, and the first groove, the second groove and the third groove intersect each other two by two.

Optionally, the acute angle included angle between the second groove and the third groove is α, the acute angle included angle between the third groove and the first groove is β, and the acute angle included angle between the second groove and the first groove is γ, where α, β, and γ satisfy: alpha is more than or equal to 0.12 DEG and less than or equal to 12 DEG, and/or beta=gamma= (90 DEG alpha)/2.

Alternatively to this, the method may comprise,

the intersection part of the first groove and the second groove is an arc-shaped groove; and/or the number of the groups of groups,

the intersection part of the second groove and the third groove is an arc groove.

Optionally, the radius of the arc-shaped groove is R, where R satisfies: r is more than 0 and less than or equal to 2mm.

Optionally, ends of the second groove and the third groove which are adjacently arranged are overlapped.

An electric core comprises a negative electrode plate and a positive electrode plate, wherein the positive electrode plate and/or the negative electrode plate is the electrode plate.

Optionally, the positive plate includes a positive current collector, and a positive active material layer and an insulating layer coated on the positive current collector, the positive active material layer has a fifth edge near the insulating layer and a sixth edge far from the insulating layer, and a distance between the first groove near the fifth edge and the fifth edge is T ₃ Wherein: t (T) ₃ ≥1.9mm。

Optionally, the distance between the first groove near the sixth edge and the sixth edge is B ₃ Wherein: b (B) ₃ Not less than 1.4mm; and/or the distance between the end of the second groove close to the fifth edge and the fifth edge is T ₄ Wherein: t (T) ₄ More than or equal to 0.1mm; and/or the distance between the end of the second groove close to the sixth edge and the sixth edge is B ₄ Wherein: b (B) ₄ ≥0mm。

The pole piece that this application provided, the quantity through the quantity of second recess is greater than the quantity of first recess, will set up relatively less along the quantity of first recess of first direction, because the first recess along the first direction can restrict the horizontal diffusion of lithium ion, reduces the influence to lithium ion diffusion efficiency. While the diffusion direction of lithium ions is generally perpendicular to the surface of the current collector, by increasing the number of second grooves along the second direction, more diffusion channels can be provided, making lithium ions more easily intercalated and deintercalated in the active material layer. By increasing the number of second grooves in the second direction, the electrode surface area can also be increased, helping to provide more active material in contact with the electrolyte, thereby increasing the rate of intercalation and deintercalation of lithium ions. Reducing the transport resistance of lithium ions in the active material tends to reduce the difficulty of wetting with the electrolyte.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present application, and that other drawings may be obtained according to the provided drawings without inventive effort to a person skilled in the art.

Fig. 1 is a top view of a pole piece provided in this embodiment;

FIG. 2 is a top view of a pole piece in another embodiment;

FIG. 3 is a top view of a pole piece in one embodiment;

FIG. 4 is a cross-sectional view of the B-B position of FIG. 3;

FIG. 5 is a cross-sectional view taken at position A-A of FIG. 3;

FIG. 6 is a cross-sectional view of the C-C position of FIG. 3;

FIG. 7 is a top view of a pole piece in another embodiment;

FIG. 8 is a cross-sectional view of the E-E position of FIG. 7;

FIG. 9 is a cross-sectional view of the D-D position of FIG. 7;

FIG. 10 is a cross-sectional view of the F-F position of FIG. 7;

FIG. 11 is a top view of a tab and pole piece of one embodiment of a laminated cell;

FIG. 12 is a top view of a laminated cell with positive and negative tabs in one embodiment;

FIG. 13 is a top view of a tab and pole piece of another embodiment of a laminated cell;

fig. 14 is a top view of a laminated cell with positive and negative tabs in another embodiment;

FIG. 15 is a top view of a pole piece under one embodiment of a wound cell;

FIG. 16 is a top view of a pole piece under another embodiment of a wound cell;

fig. 17 is an enlarged view at M in fig. 2.

In fig. 1-17:

1-active material layer, 2-current collector, 3-first edge, 4-second edge, 5-third edge, 6-fourth edge, 7-insulating layer, 8-fifth edge, 9-sixth edge, 10-tab;

101-first groove, 102-second groove, 103-third groove, 104-intersection of first groove and second groove, 105-arc groove.

Detailed Description

The application provides a pole piece. The application also provides an electric core comprising the pole piece.

The following description of the technical solutions in the embodiments of the present application will be made clearly and completely with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present disclosure.

As shown in fig. 1 to 17, the embodiment of the present application provides a pole piece, which can form a battery core together with structures such as a diaphragm, a tab 10 and the like. The pole piece mainly comprises a current collector 2 and an active substance layer 1 arranged on the surface of at least one side of the current collector 2, wherein a first groove 101 and a second groove 102 are formed in one side, far away from the current collector 2, of the active substance layer 1, the depths of the first groove 101 and the second groove 102 are smaller than the thickness of the active substance layer 1, the pole piece is assembled into a battery cell, and the contact area between an active substance in the active substance layer 1 and electrolyte can be increased by the arrangement, so that the transmission resistance of lithium ions in the active substance is reduced, and the infiltration difficulty of the electrolyte is reduced. The current collector 2 has first and second sides opposite in the first direction and third and fourth sides opposite in the second direction, the first grooves 101 extend in the first direction formed by pointing the first side toward the second side, the second grooves 102 extend in the second direction formed by the third and fourth sides, and the number of the second grooves 102 is greater than the number of the first grooves 101.

The first direction and the second direction are not limited. Illustratively, the first direction is a horizontal direction, and when the pole piece is a pole piece of the laminated cell, the first direction is a width direction of the pole piece, and the first direction is a direction indicated by a double-headed arrow X' in fig. 11; when the pole piece is a pole piece of the winding battery core, the first direction is the length direction of the pole piece, and the first direction is the direction indicated by a double-headed arrow X in FIG. 1. The second direction is a vertical direction, and when the pole piece is the pole piece of the laminated battery cell, the first direction is the length direction of the pole piece, and at the moment, the second direction is the direction shown by a double-headed arrow Y' in FIG. 11; when the pole piece is a pole piece of the winding battery core, the first direction is the width direction of the pole piece, and the second direction is the direction indicated by a double-headed arrow Y in FIG. 1. Since the diffusion direction of lithium ions in the lithium ion battery is perpendicular to the surface of the pole piece, the number of the second grooves 102 is increased, more diffusion channels can be provided, and the lithium ions are easier to be inserted and released in the active material layer 1; in contrast, the number of the first grooves 101 is small because the first grooves 101 may limit the horizontal diffusion of lithium ions, and thus the limitation of the movement of lithium ions can be reduced.

It should be noted that, the number of the first grooves 101 and the second grooves 102 is not limited herein, and the first grooves 101 may be one or more, and correspondingly, the second grooves 102 may be multiple, and the number of the second grooves 102 is ensured to be greater than the number of the first grooves 101.

In addition, the first direction and the second direction may be the directions between the double-headed arrow X and the double-headed arrow Y, or the directions between the double-headed arrow X 'and the double-headed arrow Y', as long as the first direction and the second direction are ensured to be different. Preferably, the first groove 101 and the second groove 102 intersect, so that the infiltration efficiency of the electrolyte in the active material layer 1 can be improved, and the movement efficiency of lithium ions can be improved.

The number of the first grooves 101 along the first direction is set relatively small by the number of the second grooves 102 being larger than the number of the first grooves 101, because the first grooves 101 along the first direction may limit the horizontal diffusion of lithium ions, and reduce the influence on the diffusion efficiency of lithium ions. While the diffusion direction of lithium ions is generally perpendicular to the surface of the current collector 2, by increasing the number of second grooves 102 in the second direction, more diffusion channels can be provided, making it easier for lithium ions to be intercalated and deintercalated in the active material layer 1. By increasing the number of second grooves 102 in the second direction, the electrode surface area may also be increased, helping to provide more active material in contact with the electrolyte, thereby increasing the rate of intercalation and deintercalation of lithium ions. Reducing the transport resistance of lithium ions in the active material tends to reduce the difficulty of wetting with the electrolyte.

In addition, the pole piece can be either a positive pole piece or a negative pole piece, that is, the first groove 101 and the second groove 102 can be formed on the active material layer 1 of the positive pole or on the active material layer 1 of the negative pole, when the surfaces of both sides of the current collector 2 are coated with the active material layer 1, the surfaces of the active material layers 1 on both sides are formed with grooves, and the grooves formed by the active material layers 1 on both sides of the current collector 2 are aligned, and it is required to be stated that the alignment includes the complete alignment of the two grooves, and the positions of the grooves on both sides are allowed to have a slight deviation, and the deviation of the grooves on both sides of the current collector 2 in the surface direction of the current collector 2 is between-100 μm and 100 μm.

In general, when processing a pole piece, the active material layer 1 is first coated on the current collector 2, and then the current collector 2 coated with the active material layer 1 is rolled by using a pressing roller to form a material strip, but since the material strip needs to be cut multiple times in the first direction and the second direction to form a pole piece, a laser is used to scribe and slot the active material layer 1 of the material strip, in order to improve the efficiency of scribing and slot, a plurality of lasers are generally used to scribe and slot the material strip in different directions and in different areas, and then the material strip is cut into pole pieces by a pole piece cutting device. However, in the above-mentioned junction of scribing and slotting the material strip by using multiple lasers, the situation that the splicing parts of the first groove 101 and/or the second groove 102 overlap, cross, break, etc. may occur, because the first groove 101 and the second groove 102 located at one side of the break area are mutually communicated, at least one of the first groove 101 and the second groove 102 located at one side of the break area on the same pole piece needs to be ensured to extend to at least one end face of the active material layer 1, and the first groove 101 and the second groove 102 located at the other side of the break area on the same pole piece are also so arranged, so that the circulation of the electrolyte in the groove of the active material layer 1 can be further accelerated, so that the electrolyte quickly infiltrates the battery provided with the pole piece.

In some embodiments, the first grooves 101 and the second grooves 102 are each provided in plurality, and the distance between any adjacent second grooves 102 is smaller than the distance between any adjacent first grooves 101. Specifically, on the premise that the number of the second grooves 102 arranged along the second direction is larger than that of the first grooves 101 arranged along the first direction, the distance between any two adjacent second grooves 102 is ensured to be smaller than that between any two adjacent first grooves 101, and the density of the second grooves 102 arranged along the second direction is enabled to be larger than that of the first grooves 101 arranged along the first direction, so that more diffusion channels can be further provided, and lithium ions are more easily embedded and released in the active material layer 1; in contrast, the number of the first grooves 101 is small because the first grooves 101 may limit the horizontal diffusion of lithium ions, and thus the limitation of lithium ions can be reduced. The first grooves 101 may be disposed at equal intervals or non-equal intervals, and the second grooves 102 may be disposed at equal intervals or non-equal intervals.

In addition, one first groove 101 may be provided, and a plurality of second grooves 102 may be provided, so that the density of the second grooves 102 provided in the second direction is greater than that of the first grooves 101 provided in the first direction, which can achieve the above-described effect.

In some embodiments, a plurality of first grooves 101 are disposed at equal intervals, and a distance between adjacent second grooves 102 is L ₁ ，5mm≤L ₁ ≤25mm。

In some embodiments, a plurality of second grooves 102 are disposed at equal intervals, the distance between adjacent second grooves 102 being L ₂ ，0.5mm≤L ₂ ≤4mm。

Specifically, a plurality of first grooves 101 are arranged at equal intervals, and a plurality of second grooves 102 are arranged at equal intervals, so that the first grooves 101 and the second grooves 102 are uniformly arranged on the active material layer 1, the first grooves 101 and the second grooves 102 are uniformly distributed on the active material layer 1, and after the pole piece is assembled into a battery, electrolyte can quickly infiltrate the active material layer 1 along the first grooves 101 and the second grooves 102, the infiltration difficulty of the active material layer 1 is reduced, and moreover, due to the equal interval arrangement of the first grooves 101 and the second grooves 102, the movement rate of lithium ions can be improved when the battery is charged and discharged. Further, 5 mm.ltoreq.L ₁ ≤25mm、0.5mm≤L ₂ By the arrangement, the surface of the active material layer 1 contacted with the electrolyte can be ensured, and the situation that the number of the first grooves 101 and the second grooves 102 is too large is avoided, so that the energy density of a battery formed by the pole pieces is reduced.

Exemplary, L ₁ Can be 5mm, 8mm, 10mm, 13mm, 15mm, 18mm, 20mm, 22mm, 25mm; l (L) ₂ May be 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm.

In some embodiments, the width W of the first groove 101 ₁ Width W of the second groove 102 ₂ The width of the intersection 104 of the first groove and the second groove is W ₃ Wherein W is ₁ 、W ₂ W and W ₃ The method meets the following conditions: w (W) ₁ ＜W ₂ ＜W ₃ . Specifically, ensure W ₁ ＜W ₂ ＜W ₃ The electrode plate is processed into the battery core, so that the infiltration rate of electrolyte can be increased, and for the winding battery core, the electrode plate is the electrode plate of the winding battery core, the second groove 102 is in contact with the electrolyte and is a main liquid suction surface, the electrolyte infiltration can be accelerated through the arrangement of the second groove 102 along the second direction, the aging time is shortened, and the effect of a main pipeline is achieved, so that the width of the second groove 102 is larger than that of the first groove 101; while the first groove 101 mayThe electrolyte in the second groove 102 is further introduced into the battery cell to play a role of a branch pipeline, so that the infiltration speed is further accelerated, and the width of the second groove 102 is larger than that of the first groove 101 because the flow of the electrolyte in the second direction is larger than that of the electrolyte in the second direction. Further, the width of the boundary position between the first groove 101 and the second groove 102 is ensured to be larger than the width of the second groove 102, so that when the electrolyte flows to the intersection position 104 of the first groove and the second groove through the second groove 102, the circulation rate of the electrolyte can be improved, and the efficiency of the electrolyte for infiltrating the active material layer 1 is improved.

Further, taking the pole piece provided with the first groove 101 and the second groove 102 as the negative pole piece as an example, the first groove 101 and the second groove 102 satisfy the above relationship to realize stress dispersion, and the width of the second groove 102 is larger than that of the first groove 101, so that a wider incision can be formed in the active material layer 1, thereby increasing the stress generated by expansion of the negative pole material during charge and discharge, and providing a larger buffer space for expansion of the battery. The wound battery may expand during charge and discharge, and according to the structure of the wound battery, the expansion amount thereof in the tape running direction is greater than that in the non-tape running direction, and by widening the width of the second groove 102, the stress of the active material layer 1 can be reduced, and the cycle life and stability of the battery can be improved.

In some embodiments, the depth H of the first groove 101 ₁ Depth H of the second groove 102 ₂ The depth of the intersection 104 of the first groove and the second groove is H ₃ Wherein H is ₁ 、H ₂ H and H ₃ The method meets the following conditions: h ₁ ＜H ₂ ＜H ₃ ＜H ₁ +H ₂ . Specifically, since the thickness of the active material layer 1 is very thin, the depths of the first groove 101 and the second groove 102 formed on the active material layer 1 are in the micrometer level, the active material layer 1 is usually scribed by using laser to realize slotting of the active material layer 1, and the sensor is arranged to adjust the slotting position of the laser on the active material layer 1, so as to control the irradiation time of the laser and the parameters of the laser to realize scribing and slotting of the active material layer 1. While there is an intersection point due to the first groove 101 and the second groove 102 communicating with each otherWhen the laser is used to open the first groove 101 and the second groove 102 on the active material layer 1, the laser is continuously moved, if the depth of the first groove 101 and the total depth of the groove of the second groove 102 are greater than the depth of the active material layer 1, the laser may be used to open the active material layer 1 when the laser is used to open the groove of the active material layer 1, so as to increase the speed of the laser for opening the groove of the first groove 101 and the groove of the second groove 102. In addition, multiple sets of sensors may be disposed at the first groove and second groove intersection 104 to control the depth of the laser to groove at the first groove and second groove intersection 104. By arranging grooves with different depths, more uniform charge distribution and ion transmission can be realized, and the polarization phenomenon in the battery can be reduced, so that the charge-discharge balance and stability of the battery are improved. The depth of the first grooves 101 and the second grooves 102 refers to the dimension in the direction perpendicular to the surface of the current collector 2 on which the active material layer 1 is provided.

Here, guarantee H ₁ ＜H ₂ Greater depths of the second grooves 102 may provide longer ion diffusion paths, < H3 < H1+H2. Since lithium ions are diffused perpendicular to the electrode surface, increasing the depth of the second grooves 102 can lengthen the diffusion path of lithium ions in the active material layer 1; the depth of the second grooves 102 is deeper than that of the first grooves 101, so that the surface area of the active material layer 1 in contact with the electrolyte can be increased, the increased surface area helps to enhance the contact between the active material layer 1 and the electrolyte, and more opportunities for the active material to react with lithium ions are provided, which will increase the charge transport efficiency and capacity of the battery; the depth of the second groove 102 is deeper than that of the first groove 101, and deeper cracks or cuts can be formed in the active material layer 1, so that stress concentration of the electrode material can be dispersed, stress can be generated in the lithium ion battery in the charge and discharge process, the stress of the active material layer 1 can be relieved by deepening the depth of the second groove 102, and the cycle life and stability of the battery can be improved. Further, the depth of the boundary position between the first groove 101 and the second groove 102 is ensured to be larger than the depth of the second groove 102,thus, when the electrolyte flows to the junction position of the first groove 101 and the second groove 102 through the second groove 102, the circulation rate of the electrolyte can be improved, so that the efficiency of infiltrating the active material layer 1 with the electrolyte is improved.

In some embodiments, referring to fig. 11 to 16, the pole piece has a first edge 3 connected to the tab 10, an edge of the pole piece facing away from the first edge 3 is a second edge 4, an acute angle between the first direction and the first edge 3 is a, and an acute angle between the second direction and the inside of the first edge 3 is b, where a and b satisfy: a is more than or equal to 0 degree and less than or equal to 10 degrees, and/or b is more than or equal to 80 degrees and less than or equal to 90 degrees. Specifically, when the pole piece is a pole piece of the laminated battery core, the first edge 3 is an upper edge in the length direction of the pole piece in fig. 11 to 14, and the second edge 4 is a lower edge in the length direction of the pole piece in fig. 11 to 14; when the pole piece is a pole piece of a winding cell, the first edge 3 is an upper edge in the width direction of the pole piece in fig. 15 and 16, and the second edge 4 is a lower edge in the width direction of the pole piece in fig. 15 and 16. Specifically, the first direction is parallel to the first edge 3 or has an appropriate included angle, at this time, the first grooves 101 are arranged along the horizontal direction or are approximately arranged along the horizontal direction, the second direction is parallel to the first edge 3 or has an appropriate included angle, at this time, the second grooves 102 are arranged along the vertical direction or are approximately arranged along the vertical direction, and the number of the second grooves 102 is ensured to be greater than that of the first grooves 101. So arranged, since in the lithium ion battery, the diffusion direction of lithium ions is perpendicular to the surface of the pole piece, increasing the number of the second grooves 102 can provide more diffusion channels, so that lithium ions are easier to be inserted and released in the active material layer 1; in contrast, the number of the first grooves 101 is small because the first grooves 101 may limit the horizontal diffusion of lithium ions, and thus the limitation of lithium ions can be reduced.

Illustratively, a may be 0 °,1 °,2 °,3 °,5 °,6 °,8 °, or 10 °; b may be 90 °, 89 °, 88 °, 86 °, 85 °, 83 °, 82 ° or 80 °.

In some embodiments, the pole piece includes an extension extending from the current collector 2, the pole piece including a first edge 3 proximate the extension and a second edge 4 distal from the extension, proximate the first edge3 with a distance T between the first groove 101 and the first edge 3 ₁ The distance between the first groove 101 near the second edge 4 and the second edge 4 is B ₁ The distance T between the end of the second groove 102 close to the first edge 3 and the first edge 3 is ₂ The distance between the end of the second groove 102 close to the second edge 4 and the second edge 4 is B ₂ Wherein T is ₁ 、B ₁ 、T ₂ B (B) ₂ The method meets the following conditions: t (T) ₁ Not less than 3mm, and/or B ₁ Not less than 2.5mm, and/or T ₂ 1.2mm or more, and/or B ₂ And is more than or equal to 0.7mm. Specifically, in this embodiment, the pole piece is a pole piece of a laminated battery cell, and T will be ₁ 、B ₁ 、T ₂ B (B) ₂ Within the above range, the first groove 101 is not disposed at the first edge 3 and the second edge 4, and the two ends of the second groove 102 are not extended to the first edge 3 and the second edge 4, so that the first groove 101 and the second groove 102 are extended to the first edge 3 and the second edge 4, which is beneficial to ensuring the stability of the overall structure of the active material layer 1. In addition, the active material layer 1 is provided with a thinning area near the first edge 3 and the second edge 4, so that electrolyte can enter the active material layer 1 of the pole piece from the positions of the first edge 3 and the second edge 4, and the infiltration efficiency of the electrolyte is improved. And the second grooves 102 extend to the edges of the laminated battery cells in the width direction of the electrode sheet, thus facilitating the penetration of the electrolyte into the active material layer 1 of the electrode sheet.

Exemplary, T ₁ Can be 3mm, 4mm, 5mm, 8mm, 10mm; b (B) ₁ Can be 2.5mm, 3mm, 3.5mm, 4mm, 5mm, 6mm; t (T) ₂ Can be 1.2mm, 1.5mm, 1.8mm, 2mm, 2.5mm, 3mm; b (B) ₂ May be 0.7mm, 0.8mm, 0.9mm, 1mm, 1.2mm, 1.5mm.

In some embodiments, the pole piece comprises a coating area for coating the active substance layer 1 and a hollow foil area positioned at one side of the coating area, the pole lug 10 is positioned on the hollow foil area, the pole piece is provided with a first edge 3 connected with the pole lug 10, the edge of the pole piece, which is away from the first edge 3, is provided with a second edge 4, in the first direction, the active substance layer 1 is provided with a third edge 5 close to the hollow foil area of the pole piece and a fourth edge 6 far away from the hollow foil area, and the first edge is close to the first edge 3The distance between the groove 101 and the first edge 3 is T ₅ The distance between the first groove 101 near the second edge 4 and the second edge 4 is B ₅ The distance T between the end of the second groove 102 close to the first edge 3 and the first edge 3 is ₆ The distance between the end of the second groove 102 close to the second edge 4 and the second edge 4 is B ₆ The distance between the end of the second groove 102 close to the third edge 5 and the third edge 5 is S ₁ The distance between the end of the second groove 102 near the fourth edge 6 and the fourth edge 6 is S2, wherein T ₅ 、B ₅ 、T ₆ 、B ₆ 、S ₁ S and S ₂ The method meets the following conditions: t (T) ₅ Not less than 3mm, and/or B ₅ Not less than 3mm, and/or T ₆ 0.7mm or more, and/or B ₆ 0.7mm or more, and/or S ₁ 0.1mm or more, and/or S ₂ And is more than or equal to 0mm. Specifically, T is ₅ 、B ₅ 、T ₆ 、B ₆ 、S ₁ S and S ₂ The first groove 101 and the second groove 102 are arranged within the above parameter range, that is, the first groove 101 and the second groove 102 are all four edges beyond the active material layer 1, and after the pole piece is assembled into the winding cell, the pole piece is wound, the middle part of the pole piece is contacted with electrolyte, and the electrolyte flows to each position of the pole piece along the first groove 101 and the second groove 102, so that the infiltration efficiency of the electrolyte to the active material layer 1 is accelerated.

Exemplary, T ₅ Can be 3mm, 4mm, 5mm, 8mm, 10mm; b (B) ₅ Can be 3mm, 4mm, 5mm, 8mm, 10mm; t (T) ₆ May be 0.7mm, 0.8mm, 0.9mm, 1mm, 1.2mm, 1.5mm; b (B) ₆ May be 0.7mm, 0.8mm, 0.9mm, 1mm, 1.2mm, 1.5mm; s is S ₁ Can be 0.1mm, 0.2mm, 0.3mm, 0.5mm, 0.7mm, 1mm; s is S ₂ May be 0, 0.1mm, 0.2mm, 0.3mm, 0.5mm, 0.8mm.

The first direction is the length direction of the pole piece, namely the direction indicated by a double-headed arrow X in fig. 2.

In some embodiments, a third groove 103 is further formed on a side of the active material layer 1 away from the current collector 2, the current collector 2 has a fifth side and a sixth side opposite to each other along the third direction, the third groove 103 extends along the third direction formed by pointing the fifth side to the sixth side, and the first groove 101, the second groove 102 and the third groove 103 intersect two by two. Specifically, on the basis that the first groove 101 and the second groove 102 are formed in the side, away from the current collector 2, of the active material layer 1, further, the third groove 103 is formed, so that the number of grooves formed can be further increased, the first groove 101, the second groove 102 and the third groove 103 are uniformly formed, and the surface area of the active material layer 1 in contact with the electrolyte can be increased. Moreover, the first grooves 101, the second grooves 102 and the third grooves 103 intersect with each other, so that more paths for the electrolyte to flow can be provided when the electrolyte infiltrates the active material layer 1, and the infiltration effect of the electrolyte in the active material layer 1 is improved.

It will be appreciated that the third direction is the direction indicated by the double arrow Z in fig. 2, or the direction indicated by the double arrow Z' in fig. 13.

In some embodiments, the acute angle between the second groove 102 and the third groove 103 is α, the acute angle between the third groove 103 and the first groove 101 is β, and the acute angle between the second groove 102 and the first groove 101 is γ, where α, β, and γ satisfy: alpha is more than or equal to 0.12 degrees and less than or equal to 12 degrees, and beta=gamma= (90 degrees-alpha)/2. Specifically, when α is set in the above angle range, the second groove 102 and the third groove 103 can be regarded as a folded line groove, so that the number of grooves can be further increased, and α, β and γ satisfy 0.12 ° or less α or less than 12 °, and/or β=γ= (90 ° - α)/2, so that the first groove 101, the second groove 102 and the third groove 103 can be uniformly distributed on the active material layer 1, the impregnation efficiency of the electrolyte to the lithium ion battery is improved, the efficiency of lithium ion movement during charging and discharging is improved, and the charging and discharging efficiency of the battery assembled by using the pole piece is further improved. The smaller the angle of α, the denser the second grooves 102 and the third grooves 103 are disposed; the greater the angle of α, the more sparsely the second grooves 102 and the third grooves 103 are disposed.

Illustratively, α may be 0.12 °,1 °,5 °,10 °, 12 °; correspondingly, beta can be 44.94 °, 44.5 °, 42.5 °, 40 °, 39 °; gamma may be 44.94 °, 44.5 °, 42.5 °, 40 °, 39 °.

In some embodiments, the intersection of the first groove 101 and the second groove 102 is an arcuate groove 105; and/or the intersection of the second groove 102 and the third groove 103 is an arcuate groove 105. Specifically, the intersection part of the second groove 102 and the first groove 101 is set to be the arc groove 105, and the arc groove 105 is set to enable the connection between the second groove 102 and the first groove 101 to be smoother, so that the integrity of the connection position between the second groove 102 and the first groove 101 can be ensured, the stability of the integral structure of the active material layer 1 is improved, and the infiltration efficiency can be improved when the electrolyte infiltrates the active material layer 1. The intersection part of the second groove 102 and the third groove 103 is set to be the arc groove 105, the arc groove 105 is arranged to enable the connection of the second groove 102 and the third groove 103 to be smoother, the integrity of the connection position of the second groove 102 and the third groove 103 can be guaranteed, the stability of the whole structure of the active material layer 1 is improved, and the infiltration efficiency can be improved when electrolyte infiltrates the active material layer 1.

Further, in some embodiments, the radius of the arcuate slot 105 is R, where R satisfies: r is more than 0 and less than or equal to 2mm. By way of example, R may be 0.5mm, 0.8mm, 1mm, 1.5mm, 2mm.

Here, ensuring that the radius R of the arc groove 105 is within the above range can ensure smoothness of connection between the first groove 101 and the second groove 102 and between the second groove 102 and the third groove 103, and can make the circulation of the electrolyte in the first groove 101, the second groove 102 and the third groove 103 smoother.

In some embodiments, the ends of the adjacently disposed second and third grooves 102, 103 coincide. Specifically, the ends of the second groove 102 and the third groove 103 which are adjacently arranged are overlapped, so that the second groove 102 and the third groove 103 are arranged in a zigzag shape in the direction of the first edge 3, and the arrangement quantity of the grooves on the active material layer 1 can be increased, and the efficiency of the electrolyte for infiltrating the active material layer 1 is improved. And the ends of the adjacent second grooves 102 and third grooves 103 are overlapped, so that the second grooves 102 and the third grooves 103 are linearly arranged on one side of the active material layer 1, which is far away from the current collector 2, and the infiltration efficiency of electrolyte is further improved.

An electric core comprises a positive plate and a negative plate, wherein the negative plate is the plate. The beneficial effects of the battery caused by the negative electrode sheet are shown in the above description, and are not repeated here.

In some embodiments, the positive electrode sheet includes a positive current collector 2 and a positive electrode active material layer 1 and an insulating layer 7 coated on the positive current collector 2, the positive electrode active material layer 1 having a fifth edge 8 near the insulating layer 7 and a sixth edge 9 away from the insulating layer 7, a distance T between a first groove 101 near the fifth edge 8 and the fifth edge 8 ₃ Wherein: t (T) ₃ ≥1.9mm。

In some embodiments, the distance between the first groove 101 near the sixth edge 9 and the sixth edge 9 is B ₃ The distance T between the end of the second groove 102 near the fifth edge 8 and the fifth edge 8 is ₄ The distance between the end of the second groove 102 close to the sixth edge 9 and the sixth edge 9 is B ₄ Wherein: b (B) ₃ 1.4mm or more, and/or T ₄ Not less than 0.1mm, and/or B ₄ ≥0mm。

Specifically, ensure T ₃ 、B ₃ 、T ₄ B (B) ₄ The above requirements are met, the first groove 101 and the second groove 102 are guaranteed not to be in contact with the insulating layer 7 and not to be in contact with the sixth edge 9, electrolyte is prevented from remaining in the insulating layer 7, circulation of the electrolyte in the active material layer 1 can be facilitated, and efficiency of the electrolyte infiltrating the active material layer 1 is improved. Note that, the distances between the third groove 103 and the first edge 3, the second edge 4, the third edge 5, the fourth edge 6, the fifth edge 8, and the sixth edge 9 are the same as the distances between the first groove 101 and the edges, and will not be described herein.

Exemplary, T ₃ Can be 1.9mm, 2mm, 2.5mm, 3mm; b (B) ₃ May be 1.4mm, 1.5mm, 1.8mm, 2mm, 2.5mm; t (T) ₄ May be 0.1mm, 0.3mm, 0.5mm, 0.8mm, 1mm; b (B) ₄ May be 0, 0.2mm, 0.5mm, 0.6mm, 0.8mm, 1mm.

The basic principles of the present application have been described above in connection with specific embodiments, however, it should be noted that the advantages, benefits, effects, etc. mentioned in the present application are merely examples and not limiting, and these advantages, benefits, effects, etc. are not to be considered as necessarily possessed by the various embodiments of the present application. Furthermore, the specific details disclosed herein are for purposes of illustration and understanding only, and are not intended to be limiting, as the application is not intended to be limited to the details disclosed herein as such.

The block diagrams of the devices, apparatuses, devices, systems referred to in this application are only illustrative examples and are not intended to require or imply that the connections, arrangements, configurations must be made in the manner shown in the block diagrams. As will be appreciated by one of skill in the art, the devices, apparatuses, devices, systems may be connected, arranged, configured in any manner. Words such as "including," "comprising," "having," and the like are words of openness and mean "including but not limited to," and are used interchangeably therewith. The terms "or" and "as used herein refer to and are used interchangeably with the term" and/or "unless the context clearly indicates otherwise. The term "such as" as used herein refers to, and is used interchangeably with, the phrase "such as, but not limited to.

It is also noted that in the apparatus, devices and methods of the present application, the components or steps may be disassembled and/or assembled. Such decomposition and/or recombination should be considered as equivalent to the present application.

The previous description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects without departing from the scope of the application. Thus, the present application is not intended to be limited to the aspects shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

It should be understood that the terms "first," "second," "third," "fourth," "fifth," and "sixth" used in the description of the embodiments of the present application are merely used for clarity in describing the technical solutions, and are not intended to limit the scope of the present application.

The foregoing description has been presented for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of the application to the form disclosed herein. Although a number of example aspects and embodiments have been discussed above, a person of ordinary skill in the art will recognize certain variations, modifications, alterations, additions, and subcombinations thereof.

Claims

1. The utility model provides a pole piece, includes the electric current collector and set up in the active material layer of electric current collector at least one side surface, its characterized in that, first recess and second recess have been seted up to one side that the active material layer kept away from the electric current collector, first recess with the degree of depth of second recess is all less than the thickness of active material layer, wherein:

the current collector has first and second sides opposite in a first direction and third and fourth sides opposite in a second direction, the first grooves extending in a first direction formed by the first sides pointing toward the second side, the second grooves extending in a second direction formed by the third and fourth sides, the number of the second grooves being greater than the number of the first grooves.

2. The pole piece of claim 1, wherein the first recess and the second recess are each provided with a plurality.

3. A pole piece according to claim 2, characterized in that the distance between any adjacent second grooves is smaller than the distance between any adjacent first grooves.

4. A pole piece according to claim 2, wherein a plurality of the first grooves are arranged at equal intervals, the distance between adjacent first grooves being L ₁ ，5mm≤L ₁ Less than or equal to 25mm; and/or the number of the groups of groups,

5. The pole piece of claim 1, wherein the first groove and the second groove intersect.

6. The pole piece of claim 5, wherein the width W of the first recess ₁ Width W of the second groove ₂ The width of the intersection position of the first groove and the second groove is W ₃ Wherein W is ₁ 、W ₂ W and W ₃ The method meets the following conditions: w (W) ₁ ＜W ₂ ＜W ₃ The method comprises the steps of carrying out a first treatment on the surface of the And/or the number of the groups of groups,

7. The pole piece of claim 1, wherein the pole piece has a first edge connecting the tabs, an edge of the pole piece facing away from the first edge is a second edge, an acute angle between the first direction and the first edge is a, and an acute angle between the second direction and the first edge is b, wherein a and b satisfy: a is more than or equal to 0 degree and less than or equal to 10 degrees, and/or b is more than or equal to 80 degrees and less than or equal to 90 degrees.

8. The pole piece of claim 1, wherein the pole piece includes an extension extending from the current collector, the pole piece including a first edge proximate the extension and a second edge distal from the extension, the first recess proximate the first edge being a distance T from the first edge ₁ The distance between the first groove near the second edge and the second edge is B ₁ The distance between the end of the second groove close to the first edge and the first edge is T ₂ The distance between the end of the second groove close to the second edge and the second edge is B ₂ Wherein T is ₁ 、B ₁ 、T ₂ B (B) ₂ The method meets the following conditions: t (T) ₁ Not less than 3mm, and/or B ₁ Not less than 2.5mm, and/or T ₂ 1.2mm or more, and/or B ₂ ≥0.7mm。

9. The pole piece of claim 1, wherein the pole piece comprises a coating region for coating the active material layer and a hollow foil region on one side of the coating region, a tab is positioned on the hollow foil region, the pole piece has a first edge connected with the tab, the edge of the pole piece facing away from the first edge is a second edge, in the first direction, the active material layer has a third edge near the hollow foil region of the pole piece and a fourth edge far from the hollow foil region, and the distance between the first groove near the first edge and the first edge is T ₅ The distance between the first groove and the second edge near the second edge is B ₅ The distance between the end of the second groove close to the first edge and the first edge is T ₆ The distance between the end of the second groove close to the second edge and the second edge is B ₆ The distance between the end of the second groove close to the third edge and the third edge is S ₁ The distance between the end of the second groove close to the fourth edge and the fourth edge is S2, wherein T is ₅ 、B ₅ 、T ₆ 、B ₆ 、S ₁ S and S ₂ The method meets the following conditions: t (T) ₅ Not less than 3mm, and/or B ₅ Not less than 3mm, and/or T ₆ 0.7mm or more, and/or B ₆ 0.7mm or more, and/or S ₁ 0.1mm or more, and/or S ₂ ≥0mm。

10. The pole piece according to claim 1 or 9, wherein a third groove is further formed in a side, away from the current collector, of the active material layer, the current collector is provided with a fifth side and a sixth side which are opposite to each other along a third direction, the third groove extends along a third direction formed by pointing the fifth side to the sixth side, and the first groove, the second groove and the third groove are intersected two by two.

11. The pole piece of claim 10, wherein the acute included angle between the second groove and the third groove is α, the acute included angle between the third groove and the first groove is β, and the acute included angle between the second groove and the first groove is γ, wherein α, β, and γ satisfy: alpha is more than or equal to 0.12 DEG and less than or equal to 12 DEG, and/or beta=gamma= (90 DEG alpha)/2.

12. The pole piece of claim 10, wherein the pole piece is configured to,

13. The pole piece of claim 12, wherein the radius of the arcuate slot is R, wherein R satisfies: r is more than 0 and less than or equal to 2mm.

14. The pole piece of claim 10, wherein ends of the second and third recesses disposed adjacently coincide.

15. An electrical core, comprising a negative electrode sheet and a positive electrode sheet, wherein the positive electrode sheet and/or the negative electrode sheet is the electrode sheet according to any one of claims 1-14.

16. The cell of claim 15, wherein the positive electrode sheet comprises a positive current collector and a positive electrode active material layer and an insulating layer coated on the positive current collector, the positive electrode active material layer having a fifth edge near the insulating layer and a sixth edge away from the insulating layer, a distance between the first groove near the fifth edge and the fifth edge being T ₃ Wherein: t (T) ₃ ≥1.9mm。

17. An electrical according to claim 16A core, characterized in that the distance between the first groove near the sixth edge and the sixth edge is B ₃ Wherein: b (B) ₃ Not less than 1.4mm; and/or the distance between the end of the second groove close to the fifth edge and the fifth edge is T ₄ Wherein: t (T) ₄ More than or equal to 0.1mm; and/or the distance between the end of the second groove close to the sixth edge and the sixth edge is B ₄ Wherein: b (B) ₄ ≥0mm。