CN219435902U - Pole piece structure, battery monomer and battery - Google Patents

Abstract

The application relates to the field of batteries and provides a pole piece structure, a battery monomer and a battery capable of reducing lithium separation risk. The pole piece structure comprises: the positive pole piece and negative pole piece, the surface of positive pole piece is provided with a first active material layer, the surface of negative pole piece is provided with a second active material layer, the first active material layer is provided with a concave part which is concave along a first direction, the second active material layer is provided with a convex part which is convex along the first direction, at least part of the convex part is used for being embedded into the concave part, the height of the convex part along the first direction is Ha, the depth of the concave part along the first direction is Hc, and Ha/Hc is more than or equal to 0.5 and less than or equal to 1. The battery cell comprises the pole piece structure. The battery comprises the single battery.

Description

Pole piece structure, battery monomer and battery

Technical Field

The application relates to the field of batteries, in particular to a pole piece structure, a battery monomer and a battery.

Background

Along with the rapid development of the new energy automobile industry, the battery is used as an important part of the new energy automobile and becomes a key for influencing the safety of the new energy automobile.

During the use process of the battery, a lithium precipitation phenomenon which influences the use safety of the battery can occur. During the charging process of the battery, lithium ions can not enter the negative electrode after being released from the positive electrode, and lithium ions form a lithium simple substance on the surface of the negative electrode. The lithium precipitation not only reduces the battery performance and shortens the cycle life greatly, but also limits the quick charge capacity of the battery, and can cause disastrous consequences such as combustion, explosion and the like.

Disclosure of Invention

In view of the above, the present application provides a pole piece structure, a battery cell and a battery, which can reduce the risk of lithium precipitation in the use process of the battery.

In a first aspect, the present application provides a pole piece structure comprising: the positive pole piece and negative pole piece, the surface of positive pole piece is provided with a first active material layer, the surface of negative pole piece is provided with a second active material layer, the first active material layer is provided with a concave part which is concave along a first direction, the second active material layer is provided with a convex part which is convex along the first direction, at least part of the convex part is used for being embedded into the concave part, the height of the convex part along the first direction is Ha, the depth of the concave part along the first direction is Hc, and Ha/Hc is more than or equal to 0.5 and less than or equal to 1.

In the technical scheme of this embodiment, be formed with on the first active material layer on positive pole piece surface along the sunken depressed part of first direction, be formed with on the second active material layer on negative pole piece surface along the bellied bellying of first direction, the bellying is arranged in the embedding depressed part. After the protruding part is embedded into the concave part, when the positive electrode plate and the negative electrode plate are expanded and deformed, the protruding part is positioned in the concave part or is close to the first active material layer, so that a part with a relatively close distance is still arranged between the first active material layer and the second active material layer, the diffusion distance of lithium ions is reduced, and the risk of lithium precipitation can be further reduced. Further, the distance between the first active material layer and the second active material layer is short, so that the risk of gas generation in the battery between the first active material layer and the second active material layer can be reduced, and the risk of lithium precipitation can be reduced. In the pole piece structure of the embodiment of the application, ha/Hc is more than or equal to 0.5 and less than 1, and the design is carried out in such a way that the size of a gap between the bulge and the recess is within a certain range, and through experiments, the size range can better prevent the occurrence of the lithium precipitation phenomenon; meanwhile, a gap exists between the protruding part and the recessed part in the first direction, so that a part of gap can still be reserved between the positive pole piece and the negative pole piece, and the liquid retaining capacity can be improved to improve the circulation performance.

In some embodiments, the pole piece structure further comprises: and the isolating film is arranged between the positive electrode plate and the negative electrode plate, a first gap is formed between the protruding part and the concave part in the first direction, and the width of the first gap at least part of the positions is larger than the thickness of the isolating film.

In the pole piece structure of the embodiment of the application, the isolating film is used for separating the positive pole piece from the negative pole piece, so that the direct contact of the positive pole piece and the negative pole piece is avoided to short-circuit. The first clearance is formed between bellying and the depressed part, and the width of first clearance in the position of at least part department is greater than the thickness of the barrier film of here, so design for all there is the clearance between barrier film and bulge and the depressed part, and this clearance can be used for holding electrolyte, reduces because electrolyte infiltration positive pole piece and negative pole piece are not enough and the possibility of lithium evolution, further reduces the risk of lithium evolution.

In some embodiments, 0.5.ltoreq.Ha/Hc.ltoreq.0.8.

In the pole piece structure of the embodiment of the application, ha/Hc is more than or equal to 0.5 and less than or equal to 0.8, and the design is such that enough gaps can be reserved between the positive pole piece and the negative pole piece, and the circulation performance is improved by improving the liquid retaining capacity.

In some embodiments, the maximum dimension of the protrusion in the perpendicular direction to the first direction is Wa, and the maximum dimension of the recess in the perpendicular direction to the first direction is Wc, 0.8. Ltoreq.Wa/Wc. Ltoreq.1.

In some embodiments, wa/wc=0.92.

In some embodiments, the geometric center of the protrusion is a distance ΔW,0 ΔW 1/2 (Wc Wa) from the geometric center of the recess in a direction perpendicular to the first direction.

In some embodiments, Δw=0.

In some embodiments, the plurality of concave portions are arranged at intervals along the vertical direction of the first direction, the plurality of convex portions are arranged at intervals along the vertical direction of the first direction, and the convex portions and the concave portions are in one-to-one correspondence.

In a second aspect, the present application provides a battery cell comprising the pole piece structure of the above embodiment.

In a third aspect, the present application provides a battery comprising the battery cell of the above embodiment.

The foregoing description is only an overview of the technical solutions of the present application, and may be implemented according to the content of the specification in order to make the technical means of the present application more clearly understood, and in order to make the above-mentioned and other objects, features and advantages of the present application more clearly understood, the following detailed description of the present application will be given.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the application. Also, like reference numerals are used to designate like parts throughout the accompanying drawings. In the drawings:

fig. 1 is a schematic structural diagram of a positive electrode sheet according to some embodiments of the present application;

FIG. 2 is a schematic structural view of a negative electrode tab according to some embodiments of the present application;

FIG. 3 is a schematic illustration of the structure of a pole piece according to some embodiments of the present application;

fig. 4 is a schematic structural view of a pole piece structure according to some embodiments of the present application, which illustrates a state in which a positive pole piece has a plurality of concave portions and a negative pole piece has a plurality of convex portions.

Reference numerals in the specific embodiments are as follows:

positive electrode sheet 100, first active material layer 101, recess 1011;

negative electrode sheet 200, second active material layer 201, and protruding portion 2011.

Detailed Description

Embodiments of the technical solutions of the present application will be described in detail below with reference to the accompanying drawings. The following examples are only for more clearly illustrating the technical solutions of the present application, and thus are only examples, and are not intended to limit the scope of protection of the present application.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having" and any variations thereof in the description and claims of the present application and in the description of the figures above are intended to cover non-exclusive inclusions.

In the description of the embodiments of the present application, the technical terms "first," "second," etc. are used merely to distinguish between different objects and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated, a particular order or a primary or secondary relationship. In the description of the embodiments of the present application, the meaning of "plurality" is two or more unless explicitly defined otherwise.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.

In the description of the embodiments of the present application, the term "and/or" is merely an association relationship describing an association object, which means that three relationships may exist, for example, a and/or B may mean: a exists alone, A and B exist together, and B exists alone. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.

In the description of the embodiments of the present application, the term "plurality" refers to two or more (including two), and similarly, "plural sets" refers to two or more (including two), and "plural sheets" refers to two or more (including two).

In the description of the embodiments of the present application, the orientation or positional relationship indicated by the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are based on the orientation or positional relationship shown in the drawings, and are merely for convenience of describing the embodiments of the present application and for simplifying the description, rather than indicating or implying that the apparatus or element referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the embodiments of the present application.

In the description of the embodiments of the present application, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured" and the like are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally formed; or may be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the embodiments of the present application will be understood by those of ordinary skill in the art according to the specific circumstances.

Currently, the application of power batteries is more widespread from the development of market situation. The power battery is not only applied to energy storage power supply systems such as hydraulic power, firepower, wind power and solar power stations, but also widely applied to electric vehicles such as electric bicycles, electric motorcycles, electric automobiles and the like, and various fields such as aerospace and the like. With the continuous expansion of the application field of the power battery, the market demand of the power battery is also continuously expanding.

In the long-term use process of the battery, along with the charge and discharge circulation of the battery, positive electrode active substances and negative electrode active substances can be embedded into or separated from ions, and the battery core can bulge due to the side reaction accumulation thickness of a battery core system, the stripping of a graphite sheet layer and the like, namely, the positive electrode sheet and the negative electrode sheet expand outwards. The expansion of the electrode sheet has an adverse effect on the performance and service life of the battery, for example, the expansion increases the gap between the positive electrode sheet and the negative electrode sheet, which causes the ion transmission path to change, resulting in a problem of lithium precipitation.

In order to slowly analyze the problem of lithium, this application embodiment is through design bellying and depressed part on the active material layer, and the bellying is used for embedding the depressed part, after anodal pole piece and negative pole piece expansion deformation, the bellying still can be arranged in the depressed part for still there is the part that the distance is nearer between anodal active material layer and the negative pole active material layer, still can take off to insert and insert for the lithium ion and provide comparatively convenient transmission path, thereby reduced the risk of separating lithium.

The pole piece structure, the battery cell and the battery disclosed by the embodiment of the application can be used for an electric device using the battery as a power supply or various energy storage systems using the battery as an energy storage element. The powered device may include, but is not limited to, a cell phone, tablet, notebook computer, electric toy, electric tool, battery car, electric car, ship, spacecraft, etc. Among them, the electric toy may include fixed or mobile electric toys, such as game machines, electric car toys, electric ship toys, electric plane toys, and the like, and the spacecraft may include planes, rockets, space planes, and spacecraft, and the like.

Reference is made to fig. 1 and 2, and further to fig. 3, in accordance with some embodiments of the present application. The embodiment of the application provides a pole piece structure, the pole piece structure includes positive pole piece 100 and negative pole piece 200, is provided with first active material layer 101 on the surface of positive pole piece 100, is provided with second active material layer 201 on the surface of negative pole piece 200, is formed with on the first active material layer 101 along the sunken depressed part 1011 of first direction, is formed with on the second active material layer 201 along the bellied bellying 2011 of first direction, and part or the whole of bellying 2011 is used for embedding depressed part 1011.

The positive electrode tab 100 may refer to an electrode tab having a high potential containing an active material that undergoes a reduction reaction upon discharge, and the body of the positive electrode tab 100 may be made of copper foil, aluminum foil, or the like, which is made of copper, aluminum, or the like.

The first active material layer 101 is disposed on at least one of two surfaces of the positive electrode tab 100 opposite to each other in the thickness direction, and the first active material layer 101 may include constituent phases in which active material particles, a conductive agent, and a binder are mixed with each other, and pores for accommodating an electrolyte, and the active material particles may be lithium cobaltate, lithium iron phosphate, ternary lithium, lithium manganate, or the like.

The negative electrode tab 200 may refer to an electrode tab having a low potential containing an active material that undergoes oxidation reaction upon discharge, and the body of the negative electrode tab 200 may be copper foil or aluminum foil or the like.

The second active material layer 201 is disposed on at least one of two surfaces of the negative electrode tab 200 opposite in the thickness direction, and the second active material layer 201 may be carbon or silicon or the like.

As shown in fig. 3, the first direction is shown as a direction in the drawing, in other words, a direction may refer to the thickness direction of the positive electrode tab 100 and the negative electrode tab 200, B direction may refer to a direction perpendicular to the a direction, and C direction (not shown in the drawing) may refer to a direction perpendicular to both the a direction and the B direction.

The concave portions 1011 are formed on the first active material layer 101 in the first direction, and the concave portions 1011 may be formed at the time of applying the first active material layer 101, or may be formed by etching, cutting, or the like after applying the first active material layer 101, and as shown in fig. 4, the concave portions 1011 may be distributed at intervals in the B direction on the first active material layer 101.

The protruding portions 2011 may be formed on the second active material layer 201 along the first direction, or may be formed when the second active material layer 201 is coated, or may be formed by etching, cutting, or the like after the second active material layer 201 is coated, as shown in fig. 4, and a plurality of protruding portions 2011 may be distributed on the second active material layer 201 at intervals along the B direction. The cross section of the protruding portion 2011 on the plane perpendicular to the C direction may be square, rectangular, semicircular, elliptical, triangular, or the like, and the cross section of the recessed portion 1011 on the plane perpendicular to the C direction is adapted to the protruding portion 2011 so that the protruding portion 2011 can be used to be embedded in the recessed portion 1011.

Part or all of the protruding portion 2011 is used to be embedded in the recessed portion 1011, for example, after the positive electrode tab 100 and the negative electrode tab 200 are wound, the protruding portion 2011 is partially embedded in the recessed portion 1011, or the protruding portion 2011 is entirely embedded in the recessed portion 1011.

By providing the concave portion 1011 on the first active material layer 101 of the positive electrode tab 100 and providing the convex portion 2011 on the second active material layer 201 of the negative electrode tab 200, the convex portion 2011 can still be located in the concave portion 1011 or close to the first active material layer 101 when the positive electrode tab 100 and the negative electrode tab 200 are expanded and deformed, so that a portion with a relatively close distance between the first active material layer 101 and the second active material layer 201 is still provided, the diffusion distance of lithium ions is reduced, and the risk of lithium precipitation is reduced. The distance between the first active material layer 101 and the second active material layer 201 is short, and the risk of gas generation in the battery being accommodated between the first active material layer 101 and the second active material layer 201 can be reduced, and the risk of lithium precipitation can be reduced.

Optionally, referring to fig. 3, the pole piece structure further includes a separator disposed between the positive pole piece 100 and the negative pole piece 200, wherein in the first direction, a first gap is formed between the protruding portion 2011 and the recessed portion 1011, and a width of the first gap at least at a part of the position is greater than a thickness of the separator.

The width of the first gap may refer to the maximum distance between the protruding portion 2011 and the recessed portion 1011 in the first direction, and the thickness of the separation film may refer to the distance between two surfaces of the separation film opposite in the first direction.

The separator may refer to a film-like structure located between the positive electrode tab 100 and the negative electrode tab 200 and used for insulating the positive electrode tab 100 and the negative electrode tab 200, and the separator may be made of polypropylene (PP) or Polyethylene (PE).

As shown in fig. 3, after the protruding portion 2011 is embedded in the recessed portion 1011, the protruding portion 2011 and the recessed portion 1011 are formed with a first gap in the a direction, and the isolation film is located in the first gap, and a part or the whole of the width of the first gap in the first direction is larger than the width of the isolation film here, in other words, a gap exists between the isolation film and the protruding portion 2011 and/or between the isolation film and the recessed portion 1011 in the first direction. For example, the separation film may have a gap in the first direction only with the convex portion 2011, may have a gap in the first direction only with the concave portion 1011, and may have a gap in the first direction simultaneously with the concave portion 1011 and the convex portion 2011.

Taking a lithium ion battery as an example, during charging, the positive electrode tab 100 and the negative electrode tab 200 may undergo expansion deformation, and after the positive electrode tab and the negative electrode tab expand, deformation may occur in opposite directions, in other words, the positive electrode tab 100 and the negative electrode tab 200 may undergo deformation in directions close to each other, so that a space between the positive electrode tab 100 and the negative electrode tab 200 is compressed. Under normal conditions, in order to avoid lithium precipitation of the negative electrode sheet 200, the electrolyte used as a lithium ion conducting medium needs to fully infiltrate the positive electrode sheet 100 and the negative electrode sheet 200, so that lithium ions can be smoothly intercalated into the negative electrode sheet 200 through the electrolyte after deintercalation from the positive electrode sheet 100, when the electrolyte between the positive electrode sheet 100 and the negative electrode sheet 200 is extruded due to external force, the positive electrode sheet 100 and the negative electrode sheet 200 cannot be fully infiltrated, and even the electrolyte at a part of positions between the positive electrode sheet 100 and the negative electrode sheet 200 may be completely discharged, so that lithium ions deintercalated from the positive electrode sheet 100 cannot enter the negative electrode sheet 200 through the electrolyte, and lithium precipitation is formed on the negative electrode. Therefore, how to reduce the possibility of complete extrusion of the electrolyte between the positive electrode tab 100 and the negative electrode tab 200 becomes an effective way to solve the lithium precipitation of the negative electrode tab 200.

By forming a first gap between the separator and the boss 2011 and/or the recess 1011, this gap can be used to accommodate electrolyte, for example, electrolyte may be present in the gap between the separator and the boss 2011 when there is a gap in the first direction only between the separator and the boss 2011; when there is a gap between the separator and the recess 1011 in the first direction only, the electrolyte may be present in the gap between the separator and the recess 1011; when there is a gap between the separator and the concave portion 1011 and the convex portion 2011 in the first direction at the same time, the electrolyte may be present in the gap between the separator and the concave portion 1011 and the convex portion 2011. Gaps exist between the isolating film and the concave parts 1011 and/or the convex parts, so that the possibility of completely extruding electrolyte between the positive electrode pole piece 100 and the negative electrode pole piece 200 due to expansion of the positive electrode pole piece 100 and the negative electrode pole piece 200 can be effectively reduced, the possibility of lithium precipitation due to insufficient infiltration of the electrolyte into the positive electrode pole piece 100 and the negative electrode pole piece 200 is reduced, and the risk of lithium precipitation is further reduced.

The following table is the experimental data for the examples of the present application.

Example 1: the vertical direction of the first direction is the B direction, a concave part is arranged on a first active material layer of the positive electrode pole piece, a convex part is arranged on a second active material layer of the negative electrode pole piece, and after the positive electrode pole piece and the negative electrode pole piece are cold pressed, the maximum dimension Wa of the convex part 2011 along the B direction, the maximum dimension Wc of the concave part 1011 along the B direction, the height Ha of the convex part 2011 along the first direction and the depth H of the concave part 1011 along the first direction are respectively tested _C And confirms that the distance between the geometric center of the boss 2011 and the geometric center of the recess 1011 in the B direction is Δw. Then winding the positive pole piece and the negative pole piece into a bare cell (Jellyroll, JR for short), and confirming whether the thicknesses of the bare cell corresponding to the concave part and the convex part are equal to those of the bare cell without the concave part and the convex partThe thickness at the location is comparable. Then the bare cell is put into an aluminum shell to be assembled into a cell, and the charged cell is manufactured through the following procedures; after the cell is completed, a 1C/1C cycle at 25 ℃ is tested until the capacity decays to 80%, and then the cell is disassembled to confirm the cell interface and observed.

Example 2: the other steps of example 2 were the same as those of example 1 except that the number of concave portions and convex portions in the B direction was increased to two.

Example 3: the other steps of example 3 were the same as those of example 1, except that the width Wa of the convex portion of the negative electrode tab was reduced.

Example 4: the other steps of example 4 were the same as those of example 1 except that the width Wa of the convex portion of the negative electrode tab was further reduced.

Example 5: the other steps of example 5 were the same as those of example 1, except that the width Wa of the convex portion of the negative electrode tab was increased.

Example 6: the other steps of example 6 were the same as those of example 1 except that the positions of the concave portions and the convex portions were adjusted.

Example 7: the procedure of example 7 was the same as in example 1, except that the positions of the concave portions and the convex portions were further adjusted.

Example 8: the procedure of example 8 was the same as that of example 1, except that the thickness Ha of the convex portion of the negative electrode tab was reduced.

Example 9: the procedure of example 9 was the same as that of example 1, except that the thickness Ha of the convex portion of the negative electrode tab was further reduced.

Example 10: the procedure of example 10 was the same as in example 1, except that the thickness Ha of the convex portion of the negative electrode tab was increased.

Example 11: the procedure of example 11 was the same as that of example 1, except that the thickness Ha of the convex portion of the negative electrode tab was further increased.

Comparative example 1: the procedure of comparative example 1 was the same as in example 1, except that the positive and negative electrode sheets were uniformly coated (no concave portion and convex portion were provided).

Comparative example 2: the procedure of comparative example 2 was the same as in example 1, except that the negative electrode tab was uniformly coated (no protruding portion was provided).

Optionally, in accordance with some embodiments of the present application, please refer to fig. 3. The height of the protruding portion 2011 along the first direction is Ha, and the depth of the recessed portion 1011 along the first direction is H _C ，0.5≤Ha/Hc＜1。

As shown in fig. 3, ha may refer to a distance between the farthest of the convex portion 2011 from the surface of the second active material layer 201 and the surface of the second active material layer 201, and Hc may refer to a distance between the farthest of the concave portion 1011 from the surface of the first active material layer 101 and the surface of the first active material layer 101.

0.5.ltoreq.Ha/Hc < 1 means that the height of the convex portion 2011 is smaller than the depth of the concave portion 1011 and equal to or greater than half the depth of the concave portion 1011, ha/Hc=0.5, 0.52, 0.55, 0.6, 0.65, 0.7, 0.8, 0.81, 0.9 or 0.95. By the design, the concave part 1011 can completely accommodate the convex part 2011, and meanwhile, a gap exists between the convex part 2011 and the concave part 1011 in the first direction, so that a part of gap can still be reserved between the expanded positive electrode sheet 100 and the expanded negative electrode sheet 200. Optionally, ha/Hc is more than or equal to 0.5 and less than or equal to 0.8, and the gap between the positive electrode plate 100 and the negative electrode plate 200 after expansion in the range can effectively improve the liquid retaining capacity and further improve the cycle performance.

If the height of the protruding portion 2011 of the negative electrode tab 200 is greater than the depth of the recessed portion 1011 of the positive electrode tab 100, after the positive electrode tab 100 and the negative electrode tab 200 are wound, the protruding portion 2011 cannot be fully contained in the recessed portion 1011, and the whole structure formed by winding the positive electrode tab 100 and the negative electrode tab 200 is thicker, so that the assembled battery cell is inconvenient to be put into the housing. However, the depth of the concave portion 1011 of the negative electrode tab 200 is greater than the height of the convex portion 2011 of the positive electrode tab 100, and although the concave portion 1011 can completely accommodate the convex portion 2011, the width of the first gap between the concave portion 1011 and the convex portion 2011 is too large, which may result in a risk of lithium precipitation.

Through experiments, the relation between the height of the protruding part 2011 and the depth of the recessed part 1011 is set as before, so that the overall thickness of the wound positive electrode pole piece 100 and negative electrode pole piece 200 can be reduced, and the assembled battery cell is conveniently installed into a shell; gaps exist between the expanded positive electrode sheet 100 and the expanded negative electrode sheet 200, so that the capability of retaining electrolyte (liquid retention) can be improved to improve the cycle performance, and the range of controlling the width of the first gap can be within the range of the dimensional relationship, and the risk of lithium precipitation can be further reduced.

Optionally, referring to fig. 3, a maximum dimension of the protruding portion 2011 in a vertical direction of the first direction is Wa, and a maximum dimension of the recessed portion 1011 in a vertical direction of the first direction is Wc,0.8 Wa/Wc is 1.

As shown in fig. 3, wa may refer to the width of the convex portion 2011 in the B direction, and Wc may refer to the width of the concave portion 1011 in the B direction.

The ratio of Wa/Wc 1 to Wa=0.8 represents that the width of the protruding portion 2011 is 80% -100% of the width of the recessed portion 1011, and Wa/wc=0.8, 0.82, 0.85, 0.9, 0.92, 0.95 or 1.0.

If the width of the protruding portion 2011 on the negative electrode tab 200 is greater than the width of the recessed portion 1011 on the positive electrode tab 100, the recessed portion 1011 cannot fully accommodate the protruding portion 2011, so that the rolled positive electrode tab 100 and negative electrode tab 200 are entirely thicker, and the bare cell assembled by the positive electrode tab 100 and the negative electrode tab 200 cannot be put into the case; if the width of the protruding portion 2011 is too small compared with the width of the recessed portion 1011, a large gap exists between the protruding portion 2011 and the recessed portion 1011 in the direction B, and a lithium precipitation problem may occur in the gap region.

Through experiments, the dimensional relationship between the dimensions Wa and Wc of the protruding portion 2011 and the recessed portion 1011 along the direction B is designed as before, so that the overall thickness of the wound positive electrode tab 100 and negative electrode tab 200 can be reduced, the assembled battery cell can be conveniently assembled into a housing, and the risk of lithium precipitation can be further reduced by controlling the gap dimension between the protruding portion 2011 and the recessed portion 1011 along the direction B.

Optionally, wa/wc=0.92 according to some embodiments of the present application.

Wa/wc=0.92 indicates that the width of the boss 2011 accounts for 92% of the width of the recess 1011.

Through experiments, when the width of the protruding portion 2011 is 92% of the width of the recessed portion 1011, there is a better effect of reducing the risk of lithium precipitation.

Optionally, in accordance with some embodiments of the present application, the geometric center of the boss 2011 is spaced from the geometric center of the recess 1011 in the B direction by a distance ΔW,0 ΔW 1/2 (Wc Wa).

As shown in fig. 3, the protrusion 2011 and the recess 1011 need to be centered before the protrusion 2011 is embedded in the recess 1011. The geometric center of the boss 2011 and the geometric center of the recess 1011 may coincide in the B direction, or the geometric center of the boss 2011 and the geometric center of the recess 1011 may be offset in the B direction by a distance equal to or less than half the difference between the width of the recess 1011 and the width of the boss 2011.

By means of the design, the offset of the geometric center of the protruding portion 2011 and the geometric center of the recessed portion 1011 in the direction B is controlled, so that the protruding portion 2011 can be smoothly embedded into the recessed portion 1011, the risk that the protruding portion 2011 cannot be completely contained in the recessed portion 1011 is reduced, the possibility that the overall thickness of the positive electrode pole piece 100 and the negative electrode pole piece 200 is too large after being rolled is reduced, and the possibility that a bare cell cannot enter a shell is reduced.

Optionally, please refer to fig. 3, Δw=0, according to some embodiments of the present application.

When Δw=0, the geometric center of the convex portion 2011 and the geometric center of the concave portion 1011 completely coincide in the B direction.

The concave part 1011 can be further ensured to completely contain the convex part 2011, so that the thickness of the whole structure of the wound positive electrode pole piece 100 and negative electrode pole piece 200 is smaller, and the bare cell is convenient to be installed into the shell.

Optionally, referring to fig. 3 and 4, a plurality of concave portions 1011 are arranged at intervals along the B direction, a plurality of convex portions 2011 are arranged at intervals along the B direction, and the convex portions 2011 and the concave portions 1011 are in one-to-one correspondence.

Plural means two or more.

Two or more concave parts 1011 may be provided on the positive electrode sheet 100, two or more convex parts 2011 may be provided on the negative electrode sheet 200, the number of the convex parts 2011 is equal to the number of the concave parts 1011, and each convex part 2011 is embedded into one concave part 1011.

By providing the plurality of concave portions 1011 and convex portions 2011 on the positive electrode tab 100 and the negative electrode tab 200, when the positive electrode tab 100 and the negative electrode tab 200 are expanded and deformed, the plurality of convex portions 2011 distributed on the negative electrode tab 200 and the plurality of concave portions 1011 distributed on the positive electrode tab 100 can simultaneously play a role in reducing the distance between the first active material layer 101 and the second active material layer 201, so that the first active material layer 101 and the second active material layer 201 can maintain close fit in the surface extending direction along the positive electrode tab 100 and the negative electrode tab 200, and the risk of lithium precipitation is reduced.

The embodiment of the application also provides a battery cell, which comprises the pole piece structure.

The battery cells may include lithium ion secondary battery cells, lithium ion primary battery cells, lithium sulfur battery cells, sodium lithium ion battery cells, sodium ion battery cells, magnesium ion battery cells, or the like.

For example, the battery cell may include a pole piece structure, a separator, and an electrolyte, the separator is disposed between the positive pole piece 100 and the negative pole piece 200, the positive pole piece 100, the negative pole piece 200, and the separator are immersed in the electrolyte, and the positive pole piece 100 and the negative pole piece 200 may form a cylindrical winding structure, a flat cylindrical winding structure, or a lamination structure.

The pole piece structure is favorable for reducing the lithium separation risk, so that the battery monomer using the pole piece structure can also reduce the lithium separation risk, thereby improving the use safety.

The battery cells may be cylindrical, flat, rectangular, or otherwise shaped.

The embodiment of the application also provides a battery, which comprises the battery cell.

By way of example, the battery may include a housing and a plurality of the aforementioned battery cells positioned within the housing, the battery cells configured to provide electrical energy.

The battery cell is favorable for reducing the risk of lithium separation and can improve the use safety, so that the battery comprising the battery cell can also reduce the risk of lithium separation, thereby improving the use safety.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the embodiments, and are intended to be included within the scope of the claims and description. In particular, the technical features mentioned in the respective embodiments may be combined in any manner as long as there is no structural conflict. The present application is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions falling within the scope of the claims.

Claims (10)

1. A pole piece structure, characterized in that: the positive electrode plate comprises a positive electrode plate and a negative electrode plate, wherein a first active material layer is arranged on the surface of the positive electrode plate, a second active material layer is arranged on the surface of the negative electrode plate, a concave portion which is concave along a first direction is formed on the first active material layer, a convex portion which is convex along the first direction is formed on the second active material layer, at least part of the convex portion is used for being embedded into the concave portion, the height of the convex portion along the first direction is Ha, and the depth of the concave portion along the first direction is Hc, and Ha/Hc is more than or equal to 0.5 and less than or equal to 1.

2. A pole piece structure according to claim 1, characterized in that: the pole piece structure further comprises:

and the isolating film is arranged between the positive electrode plate and the negative electrode plate, a first gap is formed between the protruding part and the recessed part in the first direction, and the width of the first gap at least part of the positions is larger than the thickness of the isolating film.

3. A pole piece structure according to claim 1, characterized in that: ha/Hc is more than or equal to 0.5 and less than or equal to 0.8.

4. A pole piece structure according to claim 1, characterized in that: the maximum dimension of the protruding portion in the vertical direction of the first direction is Wa, and the maximum dimension of the recessed portion in the vertical direction of the first direction is Wc, and Wa/Wc is more than or equal to 0.8 and less than or equal to 1.

5. The pole piece structure of claim 4, wherein: wa/wc=0.92.

6. The pole piece structure of claim 5, wherein: the distance between the geometric center of the convex part and the geometric center of the concave part in the perpendicular direction of the first direction is delta W, and delta W is more than or equal to 0 and less than or equal to 1/2 (Wc-Wa).

7. The pole piece structure of claim 6, wherein: Δw=0.

8. A pole piece structure according to claim 1, characterized in that: the concave parts are arranged at intervals along the vertical direction of the first direction, the convex parts are arranged at intervals along the vertical direction of the first direction, and the convex parts correspond to the concave parts one by one.

9. A battery cell, characterized in that: a pole piece structure comprising any one of claims 1 to 8.

10. A battery, characterized in that: comprising the battery cell according to claim 9.