CN218548477U - Pole piece, roller piece, electrode assembly, battery monomer, battery and power consumption device - Google Patents

Pole piece, roller piece, electrode assembly, battery monomer, battery and power consumption device Download PDF

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Publication number
CN218548477U
CN218548477U CN202223180676.2U CN202223180676U CN218548477U CN 218548477 U CN218548477 U CN 218548477U CN 202223180676 U CN202223180676 U CN 202223180676U CN 218548477 U CN218548477 U CN 218548477U
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pole piece
recesses
unit area
battery
distribution density
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黄志翱
吴桂森
向立
韩承均
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Contemporary Amperex Technology Co Ltd
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Contemporary Amperex Technology Co Ltd
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

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Abstract

The application relates to the technical field of batteries, in particular to a pole piece, a roller piece, an electrode assembly, a battery monomer, a battery and an electric device. The concave parts are arranged on the pole piece, and the distribution density of the concave parts in the unit area on the surface of the pole piece is increased, so that the change trend of a channel formed between one side of the pole piece, provided with the concave parts, and the corresponding separator at the side is increased in the direction from the first side to the second side, and further, in the process of charging the battery, along with the expansion of the electrode assembly, the channel is extruded, so that the pressure generated in the channel is reduced in the direction from the first side to the second side to generate pressure difference, the generated gas is favorably discharged in the direction from the first side to the second side through the channel, the accumulation and the generation of bubbles in the battery are avoided, the problems of black spots, lithium precipitation and the like after the battery is formed are relieved, and the safety and the service life of the battery are improved.

Description

Pole piece, roller piece, electrode assembly, battery monomer, battery and power consumption device
Technical Field
The application relates to the technical field of batteries, in particular to a pole piece, a roller piece, an electrode assembly, a battery monomer, a battery and an electric device.
Background
In the related art, after the battery is formed, the problems of black spots, lithium precipitation and the like are easy to occur in the battery, and the safety and the service life of the battery are reduced.
SUMMERY OF THE UTILITY MODEL
Based on this, the application provides a pole piece, roller spare, electrode subassembly, battery monomer, battery and power consumption device, can alleviate black spot, the lithium separation scheduling problem that appears after the battery becomes to improve the security and the life of battery.
In a first aspect, the present application provides a pole piece, the pole piece having a first surface and a second surface disposed opposite to each other, at least one of the first surface and the second surface of the pole piece being provided with a plurality of recesses; the pole piece is provided with a first side and a second side which are oppositely arranged along the width direction of the pole piece, the distribution density of the plurality of concave parts in a unit area on the surface of the pole piece is increased along the direction from the first side to the second side; the first side points to the direction of the second side and is parallel to the width direction of the pole piece or the length direction of the pole piece; the width direction and the length direction are perpendicular to each other.
In the technical scheme of the embodiment of the application, the concave part is arranged on the pole piece, and the distribution density of the concave part in the unit area on the surface of the pole piece is in an increasing trend, so that the change trend of a channel formed between the side, provided with the concave part, of the pole piece and the separator corresponding to the side in the direction from the first side to the second side is in an increasing trend, and further, in the charging process of the battery, along with the expansion of the electrode assembly, the channel is extruded, so that the pressure generated in the channel is in a decreasing trend in the direction from the first side to the second side to generate pressure difference, and under the action of the pressure difference, the generated gas is favorably discharged in the direction from the first side to the second side through the channel, thereby avoiding the accumulation and the generation of bubbles in the battery, relieving the problems of black spots, lithium precipitation and the like after the formation of the battery, and improving the safety and the service life of the battery.
In some embodiments, the plurality of recesses are distributed with increasing density per unit area of the surface in which the plurality of recesses are located, in a direction in which the first side is directed toward the second side. In this way, as the distribution density of the plurality of recesses in the unit area on the surface of the plurality of recesses is sequentially increased, the change trend of the channel formed between the side of the pole piece provided with the recesses and the corresponding spacer on the side in the direction from the first side to the second side is an increasing trend, and further, the pressure generated in the channel is in a decreasing trend in the direction from the first side to the second side to generate a pressure difference, and the generated gas is favorably discharged in the direction from the first side to the second side through the channel under the action of the pressure difference.
In some embodiments, the distribution density of the plurality of recesses in a unit area on the surface on which the plurality of recesses are located increases linearly in a direction in which the first side points to the second side. The linear increasing mode can enable the distribution density in the unit area to be more uniformly increased, the change trend of a channel formed between one side of the pole piece, provided with the concave part, and the corresponding isolating piece on the side in the direction from the first side to the second side is a linear increasing trend, the pressure generated in the channel is further enabled to be linearly reduced in the direction from the first side to the second side, so that more uniform pressure difference is generated, and under the action of the more uniform pressure difference, the generated gas is favorably discharged in the direction from the first side to the second side through the channel, and the surface of the pole piece can be more effectively utilized.
In some embodiments, the area ratio of the plurality of recesses in a unit area on the surface on which the plurality of recesses are located increases in a direction in which the first side is directed toward the second side. The area ratio of the concave portions in the unit area region on the surface on which the concave portions are located tends to increase, that is, the distribution density of the concave portions in the unit area region on the surface on which the concave portions are located tends to increase.
In some embodiments, the ratio between the area-fraction difference within the target unit area region of the concavities and the total area-fraction of the plurality of concavities on the surface on which they reside is 0.13 to 0.875; the area ratio difference in the target unit area region is a difference between a minimum area ratio in a unit area of the concave portion and a maximum area ratio in the unit area of the concave portion. In this way, by controlling the ratio between the area-to-area ratio difference within the target unit area region of the recess and the total area-to-area ratio of the recess over its surface, it is possible to not only form a sufficient pressure difference within the channel but also avoid affecting the cell performance.
In some embodiments, the difference in area fraction within the target area unit region is from 10% to 35%, and the total area fraction of the plurality of recesses on the surface on which they are located is from 40% to 75%. Therefore, the electrode lug dislocation or too high caused by the too low area ratio difference in the target unit area is avoided to influence the wetting effect of the electrode plate by further controlling the area ratio difference in the target unit area, and by further controlling the total area fraction of the recesses, so that a pressure difference can be created in the channel that facilitates the gas discharge.
In some embodiments, the plurality of recesses are arranged in a plurality of rows on the surface on which they are located. The mode of arranging into the multirow, not only can form required pressure differential in the direction that the first side points to the second side, still be convenient for make the shaping.
In some embodiments, the line connecting all the recesses of each row is a straight line, a broken line or a curved line. In this way, the shape in which the recesses are distributed in rows can be configured more flexibly so that the recesses can be distributed in rows.
In some embodiments, the plurality of recesses are arranged in a plurality of rows along a first predetermined direction on the surface on which the plurality of recesses are located; the direction of the first side pointing to the second side, the first preset direction and the thickness direction of the pole piece are mutually perpendicular. The mode of arranging into the multirow along first preset direction not only is convenient for control the distribution density in the unit area region of concave part, still is convenient for make the shaping.
In some embodiments, the orthogonal projections of the concavities in the same row onto the reference plane are equal in area; along the direction that the first side points to the second side, the area of the orthographic projection of the concave parts in each row on the reference plane is increased; the reference plane is a plane parallel to the direction in which the first side points to the second side and a first preset direction. By controlling the variation trend of the size of the concave portion to be an increasing trend, the required distribution density in the unit area of the concave portion is conveniently obtained, and the required pressure difference is further conveniently obtained through control.
In some embodiments, the area of the orthographic projection of the recesses in each row on the reference plane increases in a direction in which the first side points toward the second side. By controlling the variation mode of the size of the concave part to be sequentially increased, the required distribution density in the unit area of the concave part is conveniently obtained, and the variation rule of the distribution density in the unit area of the concave part is controlled to be sequentially increased, so that the required pressure difference is conveniently obtained.
In some embodiments, the area of the orthographic projection of the recesses in each row on the reference plane increases linearly in a direction in which the first side points toward the second side. By controlling the variation mode of the size of the concave part to be a linear increase mode, the required distribution density in the unit area of the concave part can be conveniently obtained, the variation rule of the distribution density in the unit area of the concave part can be controlled to be a linear increase, and the required pressure difference can be conveniently obtained.
In some embodiments, the maximum spacing of any two indentations in any two adjacent rows in the direction from the first side to the second side is equal. Through the control of the maximum distance, the size of the concave part is convenient to control, and then the required distribution density in the unit area of the concave part is convenient to obtain, and further the required pressure difference is convenient to control and obtain.
In some embodiments, the orthogonal projections of the concavities in the same row onto the reference plane are equal in area; along the direction that the first side points to the second side, the area of the orthographic projection of the concave parts in each row on the reference plane is in a decreasing trend, and the maximum distance between any two concave parts in any two adjacent rows is in a decreasing trend; the reference plane is a plane parallel to the direction in which the first side points to the second side and a first preset direction. By controlling the size and spacing of the recesses, the desired density of the distribution per unit area of the recesses is facilitated, which in turn facilitates control of the desired pressure differential.
In some embodiments, in a direction in which the first side points to the second side, an area of an orthographic projection of the recesses in each row on the reference plane decreases; and/or the maximum spacing of any two recesses in any two adjacent rows in the direction in which the first side points towards the second side is smaller closer to the second side of the pole piece. By controlling the change rule of the sizes of the concave parts to be sequentially reduced and/or the change rule of the maximum distance to be sequentially reduced, the required distribution density in the unit area of the concave parts is conveniently obtained, the change rule of the distribution density in the unit area of the concave parts is also favorably controlled to be sequentially increased, and the required pressure difference is conveniently obtained by control.
In some embodiments, in a direction in which the first side points to the second side, an area of a forward projection of the recesses in each row on the reference plane decreases linearly; and/or the maximum spacing of any two recesses in any two adjacent rows in the direction from the first side to the second side decreases linearly. By controlling the change rule of the size of the concave part to be linear reduction and/or the change rule of the maximum distance to be linear reduction, the required distribution density in the unit area of the concave part is conveniently obtained, the change rule of the distribution density in the unit area of the concave part is controlled to be linear increase, and the required pressure difference is conveniently obtained.
In some embodiments, the orthographic projections of all the concavities on the reference plane are equal in area; in the direction that the first side points to the second side, the maximum distance between any two concave parts in any two adjacent rows is in a decreasing trend; the reference plane is a plane parallel to the direction in which the first side points to the second side and a first preset direction. By controlling the size of the recesses to be the same and the trend of the change in the pitch to be reduced, it is facilitated to obtain a desired distribution density per unit area of the recesses, which in turn facilitates to control a desired pressure difference.
In some embodiments, the maximum pitch of any two recesses in any two adjacent rows in the direction in which the first side points towards the second side is smaller closer to the second side of the pole piece. By controlling the change rule of the maximum distance to be sequentially reduced, the required distribution density in the unit area of the concave part is convenient to obtain, and the change rule of the distribution density in the unit area of the concave part is also beneficial to being sequentially increased, so that the required pressure difference is convenient to control and obtain.
In some embodiments, the maximum spacing of any two recesses in any two adjacent rows in a direction from the first side to the second side decreases linearly. By controlling the change rule of the maximum distance to be linear reduction, the required distribution density in the unit area of the concave part is convenient to obtain, the change rule of the distribution density in the unit area of the concave part is also facilitated to be linear increase, and the required pressure difference is convenient to obtain.
In some embodiments, the maximum spacing of any two recesses in any two adjacent rows in a direction from the first side to the second side is equal. By controlling the maximum pitch to be equal, the desired distribution density per unit area of the recess is facilitated, which in turn facilitates control of the desired pressure differential.
In some embodiments, the plurality of recesses are arranged in a plurality of columns on the surface on which the plurality of recesses are located in a direction from the first side to the second side. The mode of arranging into multiseriate along the direction of first side direction second side not only is convenient for control the distribution density in the unit area region of concave part, still is convenient for make the shaping.
In some embodiments, in a direction in which the first side points to the second side, an area of an orthographic projection of the recesses in the same column on the reference plane tends to increase; the reference plane is a plane parallel to the direction from the first side to the second side and the first preset direction, and the direction from the first side to the second side, the first preset direction and the thickness direction of the pole piece are mutually perpendicular. The size of the concave part is controlled to be increased, so that the required distribution density of the concave part in a unit area is convenient to obtain, and the required pressure difference is convenient to control and obtain.
In some embodiments, the area of the orthographic projection of the recesses in the same column on the reference plane is larger closer to the second side of the pole piece. By controlling the change rule of the sizes of the concave parts in the same row to be sequentially increased, the required distribution density in the unit area of the concave parts is conveniently obtained, and the change rule of the distribution density in the unit area of the concave parts is controlled to be sequentially increased, so that the required pressure difference is conveniently obtained.
In some embodiments, the area of the orthographic projection of the recesses in the same column on the reference plane increases linearly along the direction in which the first side points to the second side. By controlling the change rule of the sizes of the concave parts in the same row to be linearly increased, the required distribution density of the concave parts in the unit area is conveniently obtained, and the change rule of the distribution density of the concave parts in the unit area is also favorably controlled to be linearly increased, so that the required pressure difference is conveniently obtained.
In some embodiments, two adjacent recesses in the same column are equally spaced in a direction from the first side to the second side. By controlling the equal distance between two adjacent concave parts in the same column, the required distribution density in the unit area of the concave parts is convenient to obtain, and the required pressure difference is convenient to control.
In some embodiments, along the direction in which the first side points to the second side, the area of the orthographic projection of the recesses in the same column on the reference plane decreases; the distance between two adjacent concave parts in the same column in the direction from the first side to the second side is reduced; the reference plane is a plane parallel to the direction of the first side pointing to the second side and the first preset direction, and the direction of the first side pointing to the second side, the first preset direction and the thickness direction of the pole piece are mutually perpendicular. By controlling the variation trend of the size of the concave part in the same row to be a reduction trend and controlling the variation trend of the distance between two adjacent concave parts in the same row to be a reduction trend, the required distribution density in the unit area of the concave part is convenient to obtain, and the required pressure difference is convenient to control.
In some embodiments, in a direction in which the first side points to the second side, the area of the orthographic projection of the recesses in the same column on the reference plane is smaller closer to the second side of the pole piece; and/or the distance between two adjacent recesses in the same column in the direction that the first side points to the second side is smaller closer to the second side of the pole piece. By controlling the change rule of the sizes of the concave parts in the same row to be sequentially reduced and/or controlling the change rule of the distance between two adjacent concave parts in the same row to be sequentially reduced, the required distribution density of the concave parts in the unit area is conveniently obtained, the change rule of the distribution density in the unit area of the concave parts is also favorably controlled to be sequentially increased, and the required pressure difference is conveniently obtained through control.
In some embodiments, in a direction in which the first side points to the second side, an area of an orthographic projection of the recesses in the same column on the reference plane decreases linearly; and/or the distance between two adjacent concave parts in the same column in the direction that the first side points to the second side is linearly reduced. By controlling the change rule of the sizes of the concave parts in the same row to be sequentially reduced and/or controlling the change rule of the distance between two adjacent concave parts in the same row to be linearly reduced, the required distribution density of the concave parts in a unit area region is conveniently obtained, the change rule of the distribution density in the unit area region of the concave parts is also helped to be linearly increased, and the required pressure difference is conveniently obtained through control.
In some embodiments, the orthogonal projections of the recesses in the same column on the reference plane are equal in area; the distance between two adjacent concave parts in the same column in the direction from the first side to the second side is reduced; the reference plane is a plane parallel to the direction of the first side pointing to the second side and the first preset direction, and the direction of the first side pointing to the second side, the first preset direction and the thickness direction of the pole piece are mutually perpendicular. By controlling the size of the concave parts in the same row to be the same and controlling the change trend of the distance between two adjacent concave parts in the same row to be a reduction trend, the required distribution density in the unit area of the concave parts is convenient to obtain, and the required pressure difference is convenient to obtain through control.
In some embodiments, the spacing between two adjacent recesses in the same column in the direction in which the first side points towards the second side is smaller closer to the second side of the pole piece. On the basis that the sizes of the concave parts in the same row are the same, the change rule of the distance between two adjacent concave parts in the same row is controlled to be sequentially reduced, so that the required distribution density in the unit area of the concave parts is conveniently obtained, the change rule of the distribution density in the unit area of the concave parts is also controlled to be sequentially increased, and the required pressure difference is conveniently obtained.
In some embodiments, the pitch of two adjacent recesses in the same column decreases linearly in the direction from the first side to the second side. On the basis that the sizes of the concave parts in the same row are the same, the change rule of the distance between two adjacent concave parts in the same row is controlled to be linearly reduced, so that the required distribution density in the unit area of the concave parts is conveniently obtained, the change rule of the distribution density in the unit area of the concave parts is also controlled to be linearly increased, and the required pressure difference is conveniently obtained.
In some embodiments, two adjacent recesses in the same column are equally spaced in a direction from the first side to the second side. By controlling the equal distance between two adjacent concave parts in the same column, the required distribution density in the unit area of the concave parts is convenient to obtain, and the required pressure difference is convenient to control.
In some embodiments, the plurality of recesses are arranged in an array in a first direction and a second direction on the surface on which they are located; the first direction intersects the second direction. By further controlling the arrangement of the concave portions, i.e., arranging the concave portions in a manner of forming a plurality of rows in two directions, not only the required distribution density per unit area of the concave portions is facilitated, but also the manufacturing and molding are facilitated.
In some embodiments, the plurality of recesses are arranged in a plurality of rows in a first direction and a plurality of columns in a second direction on the surface; the first direction and the direction of the first side pointing to the second side are parallel to each other, and the second direction and the first preset direction are parallel to each other; the direction of the first side pointing to the second side, the first preset direction and the thickness direction of the pole piece are mutually perpendicular. By controlling the plurality of concave portions to be arranged in a plurality of rows on the surface along the direction from the first side to the second side and in a plurality of columns along the first preset direction, the required distribution density in the unit area of the concave portions and the manufacturing and forming can be further facilitated.
In some embodiments, the spacing between two adjacent recesses in the same row in the first predetermined direction is equal; and/or the spacing between two adjacent recesses in the same column in the direction in which the first side points to the second side is equal. By controlling the distance between two adjacent concave parts in the same row and the distance between two adjacent concave parts in the same column, on one hand, the size of the concave parts is convenient to control, and the required distribution density of the concave parts in a unit area region is further obtained; on the other hand, the manufacturing and molding are also convenient.
In some embodiments, in a direction in which the first side points to the second side, an area of an orthographic projection of the recesses in the same column on the reference plane increases; the reference plane is a plane parallel to the direction in which the first side points to the second side and a first preset direction. By controlling the variation trend of the concave parts in the same column to be an increasing trend, the required distribution density of the concave parts in the unit area is convenient to obtain, and the required pressure difference is convenient to control and obtain.
In some embodiments, the area of the orthographic projection of the recesses in the same column on the reference plane, in the direction from the first side to the second side, is larger closer to the second side of the pole piece. By controlling the change rules of the concave parts in the same column to be sequentially increased, the required distribution density in the unit area of the concave parts is convenient to obtain, the required change rules of the distribution density in the unit area of the concave parts are convenient to control to be sequentially increased, and the required pressure difference is convenient to control to obtain.
In some embodiments, the area of the orthographic projection of the recesses in the same column on the reference plane increases linearly along the direction from the first side to the second side. By controlling the change rule of the concave parts in the same column to be linear increase, the required distribution density of the concave parts in the unit area is convenient to obtain, the required change rule of the distribution density of the concave parts in the unit area is also convenient to control to be linear increase, and the required pressure difference is further convenient to control to obtain.
In some embodiments, the shape of the orthographic projection of the recess on the reference plane comprises at least one of a polygon, a circle, an ellipse; the reference plane is a plane parallel to the direction from the first side to the second side and the first preset direction, and the direction from the first side to the second side, the first preset direction and the thickness direction of the pole piece are mutually perpendicular. In this manner, the distribution density per unit area of the desired recess can be obtained by structuring the shape of the recess.
In some embodiments, the area of the orthographic projection of the recess on the reference plane is 1mm 2 To 100mm 2 (ii) a The reference plane is a plane parallel to the direction of the first side pointing to the second side and the first preset direction, and the direction of the first side pointing to the second side, the first preset direction and the thickness direction of the pole piece are mutually perpendicular. By controlling the size of the concave part, the required distribution density of the concave part in a unit area can be conveniently obtained, and the influence on the reliability of the pole piece caused by the overlarge or undersize of the concave part can be avoided.
In some embodiments, the plurality of recesses are arranged along a second predetermined direction, the recesses including a start end and a termination end; the second preset direction is not parallel to the direction of the first side pointing to the second side, the direction of the starting end pointing to the terminating end is not parallel to the first preset direction, and the direction of the first side pointing to the second side, the first preset direction and the thickness direction of the pole piece are perpendicular to each other. By providing a configuration in which the shape of the recess is configured to have substantially a certain length, the recess can be easily produced.
In some embodiments, the second predetermined direction and the first predetermined direction are parallel to each other; and/or the direction in which the starting end points to the terminating end and the direction in which the first side points to the second side are parallel to each other. That is, the general extending direction of the concave portion is a direction in which the first side points to the second side, and the arrangement direction is a first preset direction. This facilitates not only the fabrication of the recesses but also the desired distribution density per unit area of the recesses.
In some embodiments, the size of the recess in the first predetermined direction increases in a direction from the first side to the second side. By controlling the variation tendency of the size of the concave portion along the first preset direction to be an increasing tendency, the variation tendency of the distribution density in the unit area of the concave portion is convenient to obtain.
In some embodiments, the dimension of the recess in the first predetermined direction, in a direction in which the first side points towards the second side, is greater closer to the second side of the pole piece. By controlling the change rule of the size of the concave part along the first preset direction to be sequentially increased, the distribution density in the unit area of the concave part with the sequentially increased change rule is convenient to obtain.
In some embodiments, the size of the recess along the first preset direction increases linearly along the direction in which the first side points to the second side. By controlling the change rule of the size of the concave part along the first preset direction to be linearly increased, the distribution density of the concave part in the unit area with the linearly increased change rule is convenient to obtain.
In some embodiments, a ratio of a maximum dimension of the recess along the first predetermined direction to a minimum dimension of the recess along the first predetermined direction is greater than or equal to 1.1. Therefore, the problem that the ratio is too small and the requirement for forming enough pressure difference in the channel is difficult to meet can be avoided, and the effect of gas exhaust is further influenced.
In some embodiments, the recess extends in a straight line between the starting end and the terminating end. By configuring the recesses extending in a straight line in this manner, not only can a required distribution density per unit area be obtained, but also molding and manufacturing of the recesses can be facilitated.
In some embodiments, the direction of extension of the recess and the direction in which the first side points towards the second side are parallel to each other. At this time, the extending direction of the recess may also be regarded as a direction in which the starting end points to the terminating end. When the direction of extension of the recess and the direction in which the first side points towards the second side are parallel to each other, it is more convenient to obtain the required distribution density per area.
In some embodiments, the recess extends along a curve between the originating end and the terminating end. In this way, by constructing the concave portions extending in a curved line, it is possible to obtain a desired distribution density per unit area region and to mold and manufacture the concave portions.
In some embodiments, the pole piece comprises a current collector and an active layer, wherein the current collector is provided with a first surface and a second surface on two opposite sides, and the active layer is arranged on at least one of the first surface and the second surface; wherein, the concave part is correspondingly arranged on the active layer. Therefore, the concave part is formed on the active layer, so that damage to the current collector can be avoided, the risk of breakage of the electrode assembly is reduced, the compaction difference can be avoided, and the influence on the performance of the battery cell is avoided.
In some embodiments, the ratio of the depth of the recess to the thickness of the active layer in which it is located is one-third to three-quarters. Therefore, the phenomenon that the depth of the concave part is too low to form enough pressure difference for exhausting can be avoided, and the phenomenon that the depth of the concave part is too high to influence the electrical property of the pole piece can be avoided.
In some embodiments, the depth of the recess is 0.1mm to 2mm. In this way, the depth of the recess is further set to facilitate the formation of a sufficient pressure difference.
In a second aspect, the present application provides a roller member having a plurality of protrusions formed on an outer circumferential surface thereof; when the roller piece is rolled on the pole piece to be processed, a plurality of concave parts can be formed on the surface of the pole piece to be processed by means of a plurality of convex parts, and the pole piece can be formed.
In a third aspect, the present application provides an electrode assembly comprising a positive electrode tab, a negative electrode tab, and a separator disposed between the positive electrode tab and the negative electrode tab; the positive plate and/or the negative plate is any one of the above.
In some embodiments, the electrode assembly is a coiled structure. In this way, the electrode assembly of a winding type structure may be selectively used according to the use requirements.
In some embodiments, the electrode assembly is a laminated structure. In this manner, the electrode assembly having a stacked structure may be selectively used according to the use requirements.
In a fourth aspect, the present application provides a battery cell comprising a case and an electrode assembly as in any one of the above, the electrode assembly being housed within the case.
In a fifth aspect, the present application provides a battery comprising a battery cell of any one of the above.
In a sixth aspect, the present application provides an electrical device comprising a battery according to any one of the above, the battery being configured to provide electrical energy.
Among the technical scheme of this application embodiment, the distribution density that is the increase trend through the surperficial unit area region of structuring that corresponds at the pole piece is the concave part, make the passageway that forms in the formation in-process electrode subassembly of battery can have the pressure differential, when producing gas, gas can be discharged from the passageway with the help of the pressure differential, and then can avoid gathering and producing the bubble in that the battery is inside, the black spot that appears after having alleviated the battery formation, the lithium scheduling problem is analysed, the security and the life of battery have been improved.
The above description is only an overview of the technical solutions of the present application, and the present application may be implemented in accordance with the content of the description so as to make the technical means of the present application more clearly understood, and the detailed description of the present application will be given below in order to make the above and other objects, features, and advantages of the present application more clearly understood.
Drawings
Various additional 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. Moreover, like reference numerals are used to refer to like elements throughout. In the drawings:
FIG. 1 is a schematic illustration of a vehicle according to some embodiments of the present application;
FIG. 2 is an exploded view of a battery according to some embodiments of the present disclosure;
fig. 3 is an exploded view of a battery cell in some embodiments of the present application;
FIG. 4 is a schematic view of a pole piece from one perspective in some embodiments of the present disclosure;
FIG. 5 is a schematic view of a pole piece from another perspective in some embodiments of the present application;
FIG. 6 is a schematic view of a pole piece structure according to another embodiment of the present disclosure;
FIG. 7 is a schematic illustration of a pole piece in further embodiments of the present application;
FIG. 8 is a schematic view of a pole piece structure according to further embodiments of the present disclosure;
FIG. 9 is a schematic view of a first projection in some embodiments of the present application;
FIG. 10 is a schematic view of a second projection in some embodiments of the present application;
FIG. 11 is a schematic view of a pole piece structure according to further embodiments of the present disclosure;
FIG. 12 is a schematic view of a pole piece structure according to further embodiments of the present disclosure;
FIG. 13 is an enlarged partial view of a pole piece according to some embodiments of the present disclosure;
FIG. 14 is an enlarged partial view of a pole piece according to yet another embodiment of the present application;
FIG. 15 is a schematic view of a third projection in some embodiments of the present application;
FIG. 16 is a schematic view of a pole piece structure according to yet another embodiment of the present application;
FIG. 17 is a schematic view of a roller member from one perspective in some embodiments of the present application;
FIG. 18 is a schematic view of a roller member from another perspective in some embodiments of the present application;
FIG. 19 is a schematic view of a roller member according to further embodiments of the present application;
FIG. 20 is a schematic view of a roller member according to further embodiments of the present application;
FIG. 21 is a schematic view of an electrode assembly in some embodiments of the present application.
The reference numerals in the detailed description are as follows:
a vehicle 1000;
battery 100, controller 200, motor 300;
a box 10, a first part 11, a second part 12;
the battery cell 20, the end cap 21, the electrode terminal 21a, the case 22, the electrode assembly 23, the pole piece 231, the tab e, the current collector 2311, the active layer 2312, the positive pole piece 231a, the negative pole piece 231b, the first surface m1, the second surface m2, the first side s1, the second side s2, the recess a, the starting end a1, the terminating end a2, and the separator 232;
a roller g, a convex t;
a connection line q;
a first distance d1, a second distance d2, a third distance d3;
depth h1, thickness h2;
a reference plane R, a first projection y1, a second projection y2, a third projection y3;
dimension C, maximum dimension C max Minimum size C min ；
A width direction W, a thickness direction δ, a length direction L, a first direction F1, a second direction F2;
path r, bubble u.
Detailed Description
Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The following examples are merely used to more clearly illustrate the technical solutions of the present application, and therefore are only examples, and the protection scope of the present application is not limited thereby.
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 "including" and "having," and any variations thereof, in the description and claims of this application and the description of the above figures are intended to cover non-exclusive inclusions.
In the description of the embodiments of the present application, the technical terms "first", "second", and the like are used only for distinguishing different objects, and are not to be construed as indicating or implying relative importance or to implicitly indicate the number, specific order, or primary-secondary relationship of the technical features indicated. In the description of the embodiments of the present application, "a plurality" means two or more unless specifically defined otherwise.
Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase 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. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.
In the description of the embodiments of the present application, the term "and/or" is only one kind of association relationship describing an associated object, and means that three relationships may exist, for example, a and/or B, and may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter associated objects are in 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 pieces" refers to two or more (including two).
In the description of the embodiments of the present application, the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like, indicate the directions or positional relationships indicated in the drawings, and are only for convenience of description of the embodiments of the present application and for simplicity of description, but do not indicate or imply that the referred device or element must have a specific direction, be constructed and operated in a specific direction, and thus, should not be construed as limiting the embodiments of the present application.
In the description of the embodiments of the present application, unless otherwise explicitly stated or limited, the terms "mounted," "connected," "fixed," and the like are used in a broad sense, and for example, may be fixedly connected, detachably connected, or integrated; mechanical connection or electrical connection is also possible; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the embodiments of the present application can be understood by those of ordinary skill in the art according to specific situations.
At present, the application of the power battery is more and more extensive 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 a plurality of fields such as military equipment and aerospace. With the continuous expansion of the application field of the power battery, the market demand is also continuously expanding.
The present inventors have noticed that, after the battery is formed, problems such as black spots and lithium deposition are likely to occur in the battery, and the safety and the service life of the battery are reduced. More specifically, during formation of the battery, gases are generated inside the battery cells and are exhausted through the channels formed between the separators and the pole pieces. The resistance to which the gas is subjected when it is discharged from the channel includes at least the weight of the electrolyte and the expansion force of the cell. The gas is discharged from the channel by virtue of the self-lifting force, and the closer to the bottom of the battery cell (i.e. the side far away from the end cover), the more the gas is subjected to the gravity of the electrolyte, the slower the gas exhaust speed is, the more difficult the gas is to be discharged from the battery cell, and the gas is remained in the battery due to insufficient discharge. The residual gas exists in the form of bubbles between the separator and the electrode plate, and affects the electrochemical processes such as ion migration, and finally causes the problems of black spots, lithium deposition, and the like.
In order to alleviate the problems of black spots, lithium precipitation and the like in the battery caused by the fact that gas is left between the separator and the pole piece, the inventor of the application researches and discovers that the gas can be prevented from being left between the separator and the pole piece by accelerating the exhaust speed of the gas. Specifically, a pressure difference can be formed inside the channel, and gas is forced to be discharged from the channel through the pressure difference, so that the gas is prevented from being accumulated inside the battery and generating bubbles, and the safety and the service life of the battery are improved.
Based on the above consideration, in order to alleviate the problems of black spots, lithium deposition and the like in the battery caused by gas remaining between the separator and the pole piece, through intensive research, the inventor of the present application has designed a pole piece, by arranging a concave portion on at least one surface of the pole piece facing the separator, and by configuring the distribution density in the unit area region of the concave portion, the space in the channel formed between the corresponding pole piece and the separator is made to have a decreasing trend in the direction from the bottom of the battery cell to the top of the battery cell, so that a pressure difference can be formed in the channel, thereby accelerating the gas discharge, avoiding the problems of black spots, lithium deposition and the like caused by gas remaining, and improving the safety and the service life of the battery.
The pole piece disclosed in the embodiment of the application is used for preparing a battery monomer, and the battery monomer can be used in electric devices such as vehicles, ships or aircrafts without limitation. The power supply system with the electric device formed by the battery monomer, the battery and the like disclosed by the application can be used, so that the problems of reduction of the safety performance and the service life of the battery due to gas residue after the battery is formed can be relieved.
The embodiment of the application provides an electric device using a battery as a power supply, wherein the electric device can be but is not limited to a mobile phone, a tablet, a notebook computer, an electric toy, an electric tool, a battery car, an electric automobile, a ship, a spacecraft and the like. The electric toy may include a stationary or mobile electric toy, such as a game machine, an electric car toy, an electric ship toy, an electric airplane toy, and the like, and the spacecraft may include an airplane, a rocket, a space shuttle, a spacecraft, and the like.
For convenience of description, the following embodiments take an example in which a power consuming apparatus according to an embodiment of the present application is a vehicle 1000.
Referring to fig. 1, fig. 1 is a schematic structural diagram of a vehicle 1000 according to some embodiments of the present disclosure. The vehicle 1000 may be a fuel automobile, a gas automobile, or a new energy automobile, and the new energy automobile may be a pure electric automobile, a hybrid electric automobile, or a range-extended automobile, etc. The battery 100 is provided inside the vehicle 1000, and the battery 100 may be provided at the bottom or the head or the tail of the vehicle 1000. The battery 100 may be used for power supply of the vehicle 1000, for example, the battery 100 may serve as an operation power source of the vehicle 1000. The vehicle 1000 may further include a controller 200 and a motor 300, the controller 200 being configured to control the battery 100 to supply power to the motor 300, for example, for starting, navigation, and operational power requirements while the vehicle 1000 is traveling.
In some embodiments of the present application, the battery 100 may be used not only as an operating power source of the vehicle 1000, but also as a driving power source of the vehicle 1000, instead of or in part of fuel or natural gas, to provide driving power for the vehicle 1000.
Referring to fig. 2, fig. 2 is an exploded view of a battery 100 according to some embodiments of the present disclosure. The battery 100 includes a case 10 and a battery cell 20, and the battery cell 20 is accommodated in the case 10. The case 10 is used to provide a receiving space for the battery cells 20, and the case 10 may have various structures. In some embodiments, the case 10 may include a first portion 11 and a second portion 12, the first portion 11 and the second portion 12 cover each other, and the first portion 11 and the second portion 12 together define a receiving space for receiving the battery cell 20. The second part 12 may be a hollow structure with an open end, the first part 11 may be a plate-shaped structure, and the first part 11 covers the open side of the second part 12, so that the first part 11 and the second part 12 jointly define a containing space; the first portion 11 and the second portion 12 may be both hollow structures with one side open, and the open side of the first portion 11 may cover the open side of the second portion 12. Of course, the case 10 formed by the first and second portions 11 and 12 may have various shapes, such as a cylinder, a rectangular parallelepiped, and the like.
In the battery 100, the number of the battery cells 20 may be multiple, and the multiple battery cells 20 may be connected in series or in parallel or in series-parallel, where in series-parallel refers to both series connection and parallel connection among the multiple battery cells 20. The plurality of battery cells 20 can be directly connected in series or in parallel or in series-parallel, and the whole formed by the plurality of battery cells 20 is accommodated in the box body 10; of course, the battery 100 may also be formed by connecting a plurality of battery cells 20 in series, in parallel, or in series-parallel to form a battery module, and then connecting a plurality of battery modules in series, in parallel, or in series-parallel to form a whole, and the whole is accommodated in the box 10. The battery 100 may also include other structures, for example, the battery 100 may further include a bus member for achieving electrical connection between the plurality of battery cells 20.
Wherein each battery cell 20 may be a secondary battery or a primary battery; but is not limited to, a lithium sulfur battery, a sodium ion battery, or a magnesium ion battery. The battery cell 20 may be cylindrical, flat, rectangular parallelepiped, or other shapes.
Referring to fig. 3, fig. 3 is an exploded schematic view of a battery cell 20 according to some embodiments of the present disclosure. The battery cell 20 refers to the smallest unit constituting the battery 100. As shown in fig. 3, the battery cell 20 includes an end cap 21, a case 22, an electrode assembly 23, and other functional components.
The end cap 21 refers to a member that covers an opening of the case 22 to isolate the internal environment of the battery cell 20 from the external environment. Without limitation, the shape of the end cap 21 may be adapted to the shape of the housing 22 to fit the housing 22. Alternatively, the end cap 21 may be made of a material (e.g., an aluminum alloy) having a certain hardness and strength, so that the end cap 21 is not easily deformed when being impacted, and the battery cell 20 may have a higher structural strength and improved safety. The end cap 21 may be provided with functional components such as the electrode terminals 21 a. The electrode terminals 21a may be used to be electrically connected with the electrode assembly 23 for outputting or inputting electric energy of the battery cells 20. In some embodiments, the end cap 21 may further include a pressure relief mechanism for relieving the internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold value. In some embodiments, the end cap 21 may further include a liquid injection hole for injecting the electrolyte into the battery cell 20. The material of the end cap 21 may also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which is not limited in this embodiment. In some embodiments, insulation may also be provided on the inside of the end cap 21, which may be used to isolate the electrical connection components within the housing 22 from the end cap 21 to reduce the risk of shorting. Illustratively, the insulator may be plastic, rubber, or the like.
The case 22 is an assembly for mating with the end cap 21 to form an internal environment of the battery cell 20, wherein the formed internal environment may be used to house the electrode assembly 23, electrolyte, and other components. The housing 22 and the end cap 21 may be separate components, and an opening may be formed in the housing 22, and the opening may be covered by the end cap 21 to form the internal environment of the battery cell 20. Without limitation, the end cap 21 and the housing 22 may be integrated, and specifically, the end cap 21 and the housing 22 may form a common connecting surface before other components are inserted into the housing, and when it is necessary to enclose the inside of the housing 22, the end cap 21 covers the housing 22. The housing 22 may be a variety of shapes and sizes, such as rectangular parallelepiped, cylindrical, hexagonal prism, etc. Specifically, the shape of the case 22 may be determined according to the specific shape and size of the electrode assembly 23. The material of the housing 22 may be various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which is not limited in the embodiments of the present invention.
The electrode assembly 23 is a part in which electrochemical reactions occur in the battery cell 20. One or more electrode assemblies 23 may be contained within the case 22. Referring to fig. 21, which will be illustrated hereinafter, the electrode assembly 23 is formed mainly by winding or stacking the positive electrode tab 231a and the negative electrode tab 231b, and a separator 232 is generally provided between the positive electrode tab 231a and the negative electrode tab 231 b. The portions of the positive and negative electrode tabs 231a and 231b having the active material constitute the body portion of the electrode assembly 23, and the portions of the positive and negative electrode tabs 231a and 231b having no active material each constitute a tab e. The positive electrode tab and the negative electrode tab may be located at one end of the main body portion together or at both ends of the main body portion, respectively. During the charge and discharge of the battery 100, the positive electrode active material and the negative electrode active material react with the electrolyte, and the tab e is connected to the electrode terminal 21a to form a current loop. The separator 232 serves to separate the positive electrode tab 231a from the negative electrode tab 231b and prevent electrons in the battery cell 20 from freely passing therethrough, allowing ions in the electrolyte to freely flow between the positive electrode tab 231a and the negative electrode tab 231 b. The separator 232 may be a film made of PE (polyethylene), PP (polypropylene), etc.
According to some embodiments of the present application, referring to fig. 4 and fig. 5, fig. 4 is a schematic structural diagram of a pole piece 231 in some embodiments of the present application at one viewing angle, fig. 5 is a schematic structural diagram of the pole piece 231 in some embodiments of the present application at another viewing angle, and fig. 5 is a top view of fig. 4 relative to fig. 4. The present application provides a pole piece 231, the pole piece 231 has a first surface m1 and a second surface m2 which are oppositely arranged, at least one of the first surface m1 and the second surface m2 of the pole piece 231 is provided with a plurality of concave portions a. The pole piece 231 is provided with a first side s1 and a second side s2 which are oppositely arranged, and the distribution density of the plurality of concave parts a in the unit area on the surface of the pole piece is increased along the direction from the first side s1 to the second side s 2; the first side s1 points in the direction of the second side s2, and is parallel to the width direction W of the pole piece 231 or the length direction L of the pole piece 231; the width direction W and the length direction L are perpendicular to each other.
The first surface m1 of the pole piece 231 and the second surface m2 of the pole piece 231 are oppositely disposed, that is, the first surface m1 of the pole piece 231 and the second surface m2 of the pole piece 231 are opposite to each other in the thickness direction δ of the pole piece 231.
The recess a is intended to be arranged in a recessed configuration relative to the surface on which it is arranged. The recess a may be provided on the first surface m1 of the pole piece 231, on the second surface m2 of the pole piece 231, or on the first surface m1 of the pole piece 231 and on the second surface m2 of the pole piece 231. The setting can be performed according to actual use requirements, and the embodiment of the application does not specifically limit the setting.
The first side s1 of the pole piece 231 and the second side s2 of the pole piece 231 are with respect to the width direction W of the pole piece 231 or the length direction L of the pole piece 231. When the battery cell 20 is manufactured, the first side s1 of the pole piece 231 is close to the bottom of the battery cell 20, and the second side s2 of the pole piece 231 is close to the top of the battery cell 20. Taking the battery cell 20 illustrated in fig. 3 as an example, the top of the battery cell 20 is the side provided with the end cap 21, and the bottom of the battery cell 20 is the side opposite to the end cap 21. The first side s1 points in a direction of the second side s2, corresponding to a direction in which the bottom of the battery cell 20 points to the top. The case where the direction in which the first side s1 of the pole piece 231 points toward the second side s2 and the width direction W of the pole piece 231 are parallel to each other is illustrated in fig. 5. Referring to fig. 4 and 5, the width direction W of the pole piece 231, the length direction L of the pole piece 231, and the thickness direction δ of the pole piece 231 are perpendicular to each other, which is also illustrated in the following drawings, and the description of the width direction W, the length direction L, the thickness direction δ, and the direction from the first side s1 to the second side s2 will not be repeated.
The distribution density in the unit area region is used to represent the density of the concave portions a, and for example, refers to the proportion of the area occupied by the concave portions a in the unit area region, wherein, if all the concave portions a have the same size and the concave portions a in the unit area are completely located in the unit area, the area occupied by the concave portions a in the unit area is also equal to the number of the concave portions a in the unit area multiplied by the area occupied by a single concave portion a; if all the recesses a are not completely the same size and a part of the recesses a located in a unit area is complete and a part is incomplete, the area occupied by the recess a in the unit area is the sum of the total area occupied by all the complete recesses a in the unit area and the total area occupied by all the incomplete recesses a in the unit area. The smaller the distribution density in the unit area region, the more sparse the characteristic concave portion a is, and conversely, the more dense the characteristic concave portion a is.
Where "unit area" is for the corresponding surface of the pole piece 231, it is related to the area of the corresponding surface and the like. "area per unit area" is an area taken from the corresponding surface. The size and shape of the selected area per unit area depends on the size definition of the different area units. After the size per unit area is defined, the size of the area per unit area has a relative size and shape with respect to the corresponding surface. For example, the size of the area per unit area may be 1cm 2 (square centimeter) or 1mm 2 (square mm), also 1000mm 2 (square millimeter) 1100mm 2 (square millimeter), etc., the size of the unit area may be determined according to the size of the corresponding surface, which is not specifically limited in the embodiment of the present application. Similarly, the division of the unit area can be set by self according to the actual situation. For example, the surface of the pole piece 231 having the recess a may be divided into N × M square regions with equal areas, each region is a unit area region, where N and M are preset positive integers, and the selection of N and M is determined by the area of the surface of the pole piece 231 having the recess a. Of course, the shape of each unit area region is not limited to being square. It will be appreciated that the shape and size of each unit area region is the same. In this way, after the shape and size of the unit area region are determined, it can be seen that the distribution density in the unit area region of all the recesses a located on the same surface in the direction directed to the second side s2 along the first side s1 tends to increase. Taking the above exemplified case as an example, the size per unit area is 1cm 2 When the surface of the pole piece 231 on which the recesses a are formed is divided into N × M square regions having the same area, the unit area region closer to the first side s1 is located in front of the unit area region closer to the second side s2 in the direction from the first side s1 to the second side s2, and the area ratio of the recess a located in the previous unit area region is substantially smaller than the area ratio of the recess a located in the subsequent unit area region.
The phrase "the area ratio occupied by the concave portion a located in the former unit area region is substantially smaller than the area ratio occupied by the concave portion a located in the latter unit area region" means that the above-described tendency of increase is satisfied as a whole. Wherein, the "increasing trend" may include a stepwise increase, such as first increase, then constant, then increase, etc.; it may also include increasing all the time, such as increasing uniformly or increasing faster and then increasing slower, etc. Taking the increasing trend as first increasing, then not changing and then increasing as an example, the increasing trend is divided into three stages of "increasing first" stage, "not changing again" stage and "increasing last" stage. When the increasing trend is in the 'no longer change' stage, the area proportion occupied by the concave part a in the former unit area region and the area proportion occupied by the concave part a in the latter unit area region are equal in the unit area region in the stage, and when the increasing trend is in the 'first increasing' stage and the 'second increasing' stage, the area proportion occupied by the concave part a in the former unit area region is substantially smaller than the area proportion occupied by the concave part a in the latter unit area region. That is, the ratio of the area occupied by the concave portion a located in the former unit area region is substantially smaller than the ratio of the area occupied by the concave portion a located in the latter unit area region as a whole.
The plurality of recesses a in the surface thereof refers to a surface provided with the recesses a, and the surface may be the first surface m1 of the pole piece 231, the second surface m2 of the pole piece 231, the first surface m1 of the pole piece 231, or the second surface m2 of the pole piece 231. Fig. 5 is an example of a case where a plurality of recesses a are provided on the second surface m2 of the pole piece 231. The distribution density in the unit area region of the plurality of recesses a is with respect to the surface on which the recesses a are present, that is, the degree of density of all the recesses a on the surface with respect to the surface on which the recesses a are provided. For example, when the first surface m1 of the pole piece 231 is provided with a plurality of recesses a, the distribution density per unit area of all the recesses a on the first surface m1 of the pole piece 231 tends to increase in a direction from the first side s1 to the second side s 2. For another example, when the first surface m1 and the second surface m2 of the pole piece 231 are both provided with a plurality of recesses a, the distribution density in the unit area of all the recesses a on the first surface m1 of the pole piece 231 tends to increase in the direction from the first side s1 to the second side s2, and the distribution density in the unit area of all the recesses a on the second surface m2 of the pole piece 231 tends to increase in the direction from the first side s1 to the second side s 2. The arrangement of all the recesses a on the first surface m1 and the arrangement of all the recesses a on the second surface m2 may be the same or different. The increasing tendency of the distribution density in the unit area region of all the recesses a on the first surface m1 and the increasing tendency of the distribution density in the unit area region of all the recesses a on the second surface m2 may be the same or different. The method can be set according to actual use conditions, and the method is not particularly limited in the embodiment of the application.
The distribution density of the plurality of recesses a in the unit area on the surface thereof in the direction pointing from the first side s1 to the second side s2 tends to increase, that is, on the surface provided with the recesses a, all of the recesses a exhibit a tendency to become dense as a whole in the direction pointing from the first side s1 to the second side s2 with respect to the surface. The distribution density per unit area tends to increase, and various ways are available, for example: the number of recesses a increases in a direction from the first side s1 to the second side s 2; alternatively, the area occupied by the recesses a on the corresponding surface increases in a direction from the first side s1 toward the second side s2, i.e., the sizes of the recesses a are different. The distribution density of the plurality of concave portions a in a unit area region on the surface thereof may be made to be in an increasing tendency by the size, number, pitch between the concave portions a, and the like of the concave portions a. The method can be set according to actual use conditions, and the method is not particularly limited in the embodiment of the application.
Since the channel formed by the pole piece 231 and the corresponding spacer 232 has an increasing trend in the direction from the first side s1 to the second side s2, the channel will be pressed as the electrode assembly 23 expands during the charging process of the battery 100, the pressure borne by the position with a larger space in the channel is smaller, and the pressure borne by the position with a smaller space in the channel is larger, so that the pressure generated in the channel has a decreasing trend in the direction from the first side s1 to the second side s2, thereby generating a pressure difference. The generated gas is facilitated to be discharged in a direction in which the first side s1 is directed toward the second side s2, that is, from a structure such as a liquid injection hole provided on the top of the battery cell 20, via the passage under the action of the pressure difference. Therefore, by controlling the distribution density of the plurality of concave portions a to be changed in an increasing trend in a unit area region on the surface thereof, it is possible to avoid the occurrence of bubbles u accumulated in the battery 100, alleviate the problems of black spots, lithium deposition, and the like occurring after the formation of the battery 100, and improve the safety and the service life of the battery 100.
According to some embodiments of the present application, optionally, with continuing reference to fig. 5, along a direction from the first side s1 to the second side s2, a distribution density of the plurality of recesses a in a unit area on the surface thereof increases.
Here, "increase" is sequential increase, that is, in the direction from the first side s1 to the second side s2, the distribution density in the unit area region located upstream is smaller than the distribution density in the unit area region located downstream, and the distribution density in the unit area region is always increasing in the direction from the first side s1 to the second side s 2. "incremental" may include increasing speed faster, increasing speed slower, increasing speed first faster then not faster, increasing speed first slower then faster then not changing, etc. The "increased velocity" refers to a tendency of a change in magnitude of a difference between the distribution density in the unit area region located downstream and the distribution density in the unit area region located upstream. For example, "the increasing speed becomes faster" may mean that the difference between the distribution density in the unit area region located downstream and the distribution density in the unit area region located upstream increases in the direction in which the first side s1 is directed toward the second side s2, "the increasing speed becomes slower" may mean that the difference between the distribution density in the unit area region located downstream and the distribution density in the unit area region located upstream decreases in the direction in which the first side s1 is directed toward the second side s2, "and the increasing speed does not change" may mean that the difference between the distribution density in the unit area region located downstream and the distribution density in the unit area region located upstream does not change in the direction in which the first side s1 is directed toward the second side s 2. The "incremental" can be achieved in a variety of ways, such as by controlling the size, number, spacing between the recesses a, etc. As long as the distribution density in the unit area region located upstream is smaller than the distribution density in the unit area region located downstream in the direction from the first side s1 to the second side s2, the distribution density may be set according to the actual use situation, and this is not particularly limited by the embodiment of the present application.
In this way, since the distribution density of the plurality of recesses a in the unit area on the surface thereof is sequentially increased, the variation tendency of the channels formed between the side of the pole piece 231 provided with the recesses a and the corresponding spacer 232 on the side in the direction from the first side s1 to the second side s2 is an increasing tendency. During charging of the battery 100, as the electrode assembly 23 expands, the channel is compressed, and the pressure generated in the channel decreases in the direction from the first side s1 to the second side s2, thereby generating a pressure difference. That is, when the pressure is generated in the channel due to the expansion of the electrode assembly 23, since the pressure generated in the channel has a decreasing tendency in the direction in which the first side s1 is directed toward the second side s2, there is almost a pressure difference in the channel in the direction in which the first side s1 is directed toward the second side s2, and the gas can be forced to accelerate almost everywhere in the channel by the pressure difference. In this way, the gas entering the channel from all over or generated in all over the channel can be accelerated by the pressure difference, and the generated gas can be facilitated to be discharged in the direction in which the first side s1 is directed to the second side s2 through the channel.
According to some embodiments of the present application, optionally, with continuing reference to fig. 5, along a direction from the first side s1 to the second side s2, a distribution density of the plurality of recesses a in a unit area on the surface thereof increases linearly.
The term "linearly increases" means linearly increases, that is, the rate of increase is constant. In other words, in the direction in which the first side s1 is directed to the second side s2, the difference between the distribution density in the unit area region located downstream and the distribution density in the unit area region located upstream is constant. There are various ways of achieving "linear increase", for example by controlling the size, number of the recesses a, the spacing between the recesses a, etc. As long as the distribution density of the plurality of concave portions a in the unit area on the surface thereof increases linearly in the direction pointing to the second side s2 along the first side s1, the distribution density may be set according to the actual use situation, and the embodiment of the present application does not specifically limit this.
The linear increasing manner can increase the distribution density in the unit area more uniformly, so that the variation trend of the channel formed between the side of the pole piece 231 provided with the recess a and the corresponding spacer 232 on the side in the direction from the first side s1 to the second side s2 is a linear increasing trend, and further, the pressure generated in the channel is a linear decreasing trend in the direction from the first side s1 to the second side s2, so as to generate a more uniform pressure difference. A more uniform pressure differential is one in which the corresponding pressure differentials are substantially equal throughout the channel.
It will be appreciated that, with reference to fig. 21, which is illustrated hereinafter, the situation is illustrated in which the generated gas is discharged in the form of bubbles u following the path r. Because the migration paths r and the resistance experienced by the gases generated or entering at different positions in the channel are different, for example, the migration path r of the gas closer to the bottom of the battery cell 20 is longer, and the resistance experienced by the gravity of the electrolyte is larger, the pressure difference required by the gas closer to the bottom of the battery cell 20 is larger than the pressure difference required by the gas closer to the top of the battery cell 20. That is, it is necessary to make the pressure difference of the portion of the channel closer to the first side s1 of the pole piece 231 larger than the pressure difference of the portion closer to the second side s2 of the pole piece 231, so that in the case that the portion of the channel closer to the first side s1 of the pole piece 231 can generate a more sufficient pressure difference to accelerate the exhaust of the gas closer to the first side s1 of the pole piece 231, the pressure difference generated by the portion of the channel closer to the second side s2 of the pole piece 231 can also accelerate the exhaust of the gas closer to the second side s2 of the pole piece 231. For the generated gas, the surface topography of the pole piece 231, the pores in the pole piece 231, the gravity of the electrolyte, and the like all hinder the rising of the gas, that is, the migration path r of the gas is more complicated due to the complexity of the internal environment of the battery 100.
Based on the difference in pressure difference required by the gases at different positions and the complexity of the migration path r of the gases, the corresponding pressure difference at each position in the channel is substantially equal, which not only makes full use of the space closer to the second side s2 of the pole piece 231 when the corresponding surface of the pole piece 231 is of a limited size, but also accelerates the gases by a more uniform pressure difference, so as to alleviate the above-mentioned obstacle caused by the complexity of the internal environment of the battery 100.
Of course, along the direction from the first side s1 to the second side s2, the pressure difference generated in the channel may also be increased, or may also be increased first and then increased unchanged, or may also be increased first and then decreased, as long as the generated gas can be conveniently discharged, and the accumulation and generation of the bubbles u inside the battery 100 are avoided, which is not particularly limited in the embodiment of the present application.
According to some embodiments of the present application, optionally, with continuing reference to fig. 5, along a direction from the first side s1 to the second side s2, an area ratio of the plurality of concave portions a in a unit area on the surface on which the plurality of concave portions a are located increases.
The "area ratio per unit area" means the area ratio of the concave portion a per unit area. The area fraction of the recesses a in a unit area on the surface on which they are located can be used to characterize the density of the recesses a. The smaller the area ratio in the unit area region, the more sparse the characterization concave portion a is, and conversely, the more dense the characterization concave portion a is. In other words, the area ratio of the concave portions a per unit area on the surface on which the concave portions a are located tends to increase, that is, the distribution density of the concave portions a per unit area on the surface on which the concave portions a are located tends to increase.
As such, the trend of the distribution density of the concave portions a in the unit area region on the surface thereof can be achieved by controlling the area ratio of the concave portions a in the unit area region on the surface thereof.
According to some embodiments of the present application, optionally, with continuing reference to fig. 5, a ratio between an area-to-area ratio difference within a target unit area region of the debosses a and a total area-to-area ratio of the plurality of debosses a on the surface on which they are located is 0.13 to 0.875; the area ratio difference in the target unit area region is the difference between the minimum area ratio in the unit area of the recessed portion a and the maximum area ratio in the unit area of the recessed portion a.
"the total area occupied by the plurality of concave portions a on the surface thereof" refers to the area occupied by all the concave portions a on the surface on which the concave portions a are provided. The ratio between the area-to-area ratio difference within the target area-per-unit area of the recessions a and the total area-to-area ratio of the plurality of recessions a on the surface thereof may range from 0.13 to 0.875, and may be, for example and without limitation, 0.13, 0.2, 0.4, 0.8, 0.875, and the like.
In this manner, by controlling the ratio between the area ratio difference within the target unit area region of the recessed portion a and the total area ratio of the recessed portion a on the surface thereof, it is possible to not only form a sufficient pressure difference within the channel but also avoid affecting the performance of the battery 100.
According to some embodiments of the present application, optionally, with continued reference to fig. 5, the area fraction difference within the target unit area is 10% to 35%, and the total area fraction of the plurality of recesses a on the surface thereof is 40% to 75%.
That is, the area fraction difference within the target area unit may range from 10% to 35%, for example, and may be, but is not limited to, 10%, 15%, 18%, 25%, 30%, 35%, etc. The total area fraction of the plurality of recesses a on the surface thereof may be between 40% and 75%, for example, and may be, but is not limited to, 40%, 45%, 50%, 60%, 70%, 75%, etc.
In this way, by further controlling the area ratio difference in the target unit area, it is avoided that the electrode tab e is dislocated or too high due to too low area ratio difference in the target unit area to affect the wetting effect of the electrode tab 231, and by further controlling the total area ratio of the recess a, so that a pressure difference contributing to gas discharge can be formed in the channel.
According to some embodiments of the present application, optionally, please refer to fig. 6 to fig. 8, and refer to fig. 5 in combination, fig. 6 is a schematic structural diagram of a pole piece 231 in other embodiments of the present application, fig. 7 is a schematic structural diagram of a pole piece 231 in still other embodiments of the present application, fig. 8 is a schematic structural diagram of a pole piece 231 in still other embodiments of the present application, and a plurality of recesses a are arranged in multiple rows on a surface thereof.
Wherein "rows" represent a sequence. The rows include horizontal rows, vertical rows, and diagonal rows with respect to the width direction W of the pole piece 231. Taking the horizontal rows as an example, each horizontal row has a head end and a tail end which are oppositely arranged, and the direction in which the head end of the horizontal row points to the tail end of the horizontal row and the width direction W are perpendicular to each other, in this case, the horizontal rows may be defined as rows. Taking the vertical rows as an example, each vertical row has a head end and a tail end which are oppositely arranged, and the direction in which the head end of the vertical row points to the tail end of the vertical row and the width direction W are parallel to each other, in this case, the vertical rows may be defined as columns. Taking the slanted rows as an example, each slanted row has a head end and a tail end which are oppositely arranged, the direction in which the head end of the slanted row points to the tail end of the slanted row is arranged at an angle with the width direction W, and the angle does not include 90 °, which may be, but is not limited to, 1 °, 2 °, 30 °, 45 °, 60 °, etc. The rows and columns referred to hereinafter are defined accordingly and will not be described further. Fig. 5 illustrates a case where the plurality of concave portions a are arranged in a plurality of horizontal rows, i.e., a plurality of rows, on the second surface m2 of the pole piece 231, fig. 6 illustrates a case where the plurality of concave portions a are arranged in a plurality of vertical rows, i.e., a plurality of columns, on the second surface m2 of the pole piece 231, and fig. 7 illustrates a case where the plurality of concave portions a are arranged in a plurality of diagonal rows, on the second surface m2 of the pole piece 231.
The plurality of concave portions a may be all arranged in horizontal rows, vertical rows or oblique rows on the surface, or may include both horizontal rows and vertical rows (as shown in fig. 8), or may include both horizontal rows and oblique rows. The method can be selected according to specific arrangement conditions, and the embodiment of the application is not particularly limited to this. The dimensional specifications of the recesses a in the same row may or may not be uniform. Meanwhile, the dimensional specifications or the number of the concave portions a in different rows may be inconsistent, or some parameters may be kept consistent, or the like. The present embodiment is not particularly limited as long as the required distribution density of the recesses a per unit area can be obtained.
In this way, the arrangement in multiple rows not only enables the required pressure difference to be formed in the direction from the first side s1 to the second side s2, but also facilitates the manufacturing and forming.
According to some embodiments of the application, optionally, the connecting line q of all the recesses a of each row is a straight line, a broken line or a curved line.
A line q connecting two adjacent concave portions a of each row can be approximately regarded as a line q connecting centers of the two concave portions a. Fig. 6 is an example of a line q as a broken line, and fig. 7 and 8 are examples of a line q as a straight line. The method can be set according to the use situation, and the embodiment of the application is not particularly limited.
In this way, the shape in which the concave portions a are distributed in rows can be more flexibly configured so that the concave portions a can be distributed in rows.
According to some embodiments of the present application, optionally, with continued reference to fig. 5, the plurality of recesses a are arranged on the surface thereof in a plurality of rows along a first predetermined direction, and a direction of the first side s1 pointing to the second side s2, the first predetermined direction and the thickness direction δ of the pole piece 231 are perpendicular to each other. The sizes of the recesses a in the same row may be the same or different. The pitches between two adjacent recesses a in the same row along the first preset direction may be the same or different. The method can be set according to actual use conditions, and the method is not particularly limited in the embodiment of the application. Fig. 5 illustrates the case where the sizes of the recesses a are the same.
It is understood that in the situation illustrated in fig. 5, the direction in which the first side s1 points towards the second side s2 and the width direction W are parallel to each other, and the first predetermined direction and the length direction L are parallel to each other. Of course, when the direction of the first side s1 directed to the second side s2 and the length direction L are parallel to each other, the first preset direction and the width direction W are parallel to each other.
Therefore, the mode of arranging the concave parts in multiple rows along the first preset direction is convenient for controlling the distribution density in the unit area of the concave part a and is also convenient for manufacturing and molding.
According to some embodiments of the present application, optionally, please refer to fig. 9 in combination with fig. 5, fig. 9 is a schematic view of a first projection y1 in some embodiments of the present application, and the first projection y1 in fig. 9 is an orthographic projection of the concave portion a illustrated in fig. 5 on the reference plane R. The orthogonal projections of the concave portions a in the same row on the reference plane R have equal areas, that is, the area of the first projection y1 in the same row is equal. In the direction in which the first side s1 points to the second side s2, the area of the orthographic projection of the recesses a in each row on the reference plane R tends to increase. The reference plane R is a plane parallel to the direction in which the first side s1 points to the second side s2 and a first preset direction. That is, whether the direction in which the first side s1 points toward the second side s2 and the width direction W are parallel to each other, the first preset direction and the length direction L are parallel to each other, or the direction in which the first side s1 points toward the second side s2 and the length direction L are parallel to each other, the first preset direction and the width direction W are parallel to each other, and the reference plane R is a plane parallel to the width direction W and the length direction L. The definition of the reference plane R is used hereinafter and will not be described in detail.
The area of the orthographic projection of the recess a on the reference plane R can be regarded as the area occupied by the recess a on the surface on which it is placed. That is, the trend of change in the orthographic projection area of the concave portion a on the reference plane R can be regarded as the trend of change in the area occupied by the concave portion a on the surface thereof. Since the factors that influence the area ratio per unit area region include the area occupied by the concave portions a on the surface thereof and the intervals between the concave portions a, after the trend of the change in the area occupied by the concave portions a on the surface thereof is relatively determined, it is convenient to obtain the desired distribution density per unit area region of the concave portions a by the intervals between the concave portions a, and thus to control to obtain the desired pressure difference. For example, on the basis that the area of the orthographic projection of the concave portion a on the reference plane R in each row tends to increase, the variation tendency of the distribution density in the unit area may be a stepwise increase, a linear increase or other type of increase by changing the pitch between two adjacent concave portions a in the same row or the pitch between different rows. The method can be set according to actual use conditions, and the method is not particularly limited in the embodiment of the application.
According to some embodiments of the present application, optionally, please refer to fig. 10 in combination with fig. 8, fig. 10 is a schematic view of a second projection y2 in some embodiments of the present application, and the second projection y2 in fig. 10 is an orthographic projection of the concave portion a illustrated in fig. 8 on the reference plane R. The areas of the orthographic projections of the concave parts a in the same row on the reference plane R are equal; the area of the orthographic projection of the recesses a in each row on the reference plane R increases in a direction in which the first side s1 points toward the second side s 2. That is, in the direction in which the first side s1 points toward the second side s2, the area of the orthographic projection of the concave portion a in the upstream row on the reference plane R is smaller than the area of the orthographic projection of the concave portion a in the downstream row on the reference plane R.
By controlling the change pattern of the size of the concave portion a to be sequentially increased, it is possible to easily obtain a desired distribution density per unit area of the concave portion a, and it is also possible to easily control the change pattern of the distribution density per unit area of the concave portion a to be sequentially increased, thereby easily obtaining a desired pressure difference. Of course, in the case where the area of the orthogonal projection of the concave portion a on the reference plane R in each row increases, by controlling some of the pitches described above, the change rule of the distribution density in the unit area region of the concave portion a may be controlled to be different from other increasing rules which increase in order.
According to some embodiments of the present application, optionally, with continuing reference to fig. 10 in combination with fig. 8, the orthogonal projections of the concavities a in the same row on the reference plane R are equal in area; in the direction in which the first side s1 points towards the second side s2, the area of the orthographic projection of the recesses a in each row on the reference plane R increases linearly.
By controlling the variation of the size of the concave portion a to be linearly increased, it is possible to easily obtain a desired distribution density per unit area of the concave portion a, and it is also possible to easily obtain a desired pressure difference by controlling the variation of the distribution density per unit area of the concave portion a to be linearly increased. Of course, when the area of the orthogonal projection of the concave portion a on the reference plane R in each row increases linearly, the change rule of the distribution density in the unit area region of the concave portion a may be controlled to be other increase rule different from the linear increase by controlling some of the pitches described above.
According to some embodiments of the present application, optionally, with continuing reference to fig. 8 and 10, in a case where the orthographic projection areas of the concave portions a in the same row on the reference plane R are equal, and the orthographic projection areas of the concave portions a in each row on the reference plane R are in an increasing trend along the direction in which the first side s1 points to the second side s2, the maximum pitches of any two concave portions a in any two adjacent rows in the direction in which the first side s1 points to the second side s2 are equal.
In fig. 5, for example, the "maximum distance in the direction from the first side s1 to the second side s 2" may be regarded as the length of the projection of the line q of the two recesses a in the direction from the first side s1 to the second side s2 (i.e., the maximum first distance d 1).
The size of the concave portion a is controlled by controlling the maximum pitch, so that the required distribution density in the unit area of the concave portion a is obtained, and the required pressure difference is obtained. Of course, in the direction in which the first side s1 points to the second side s2, the trend of the maximum distance between any two concave portions a in any two adjacent rows in the direction in which the first side s1 points to the second side s2 may be a decreasing trend or an increasing trend, as long as the rule of the change of the distribution density in the unit area of the required concave portion a can be controlled and obtained in correspondence with the size of the concave portion a, which is not particularly limited in the embodiment of the present application.
According to some embodiments of the present application, optionally, the orthographic projection areas of the concavities a in the same row on the reference plane R are equal; in the direction in which the first side s1 points to the second side s2, the area of the orthographic projection of the concave portion a in each row on the reference plane R tends to decrease, and the maximum pitch between any two concave portions a in any two adjacent rows tends to decrease.
By controlling the size and the pitch of the concave portions a, a desired distribution density per unit area of the concave portions a can be obtained, and thus a desired pressure difference can be obtained. For example, in the case where the area of the orthographic projection of the concave portion a in each row on the reference plane R is in a decreasing trend and the maximum pitch between any two concave portions a in any two adjacent rows is in a decreasing trend in the direction directed from the first side s1 to the second side s2, the trend of the distribution density in the unit area of the concave portion a may be controlled to be an increasing trend, and the increasing rule in the increasing trend may include the aforementioned linear increase, stepwise increase, and the like.
According to some embodiments of the present application, optionally, the orthogonal projections of the concavities a in the same row on the reference plane R are equal in area; in the direction in which the first side s1 points towards the second side s2, the area of the orthographic projection of the recesses a in each row on the reference plane R decreases. According to some embodiments of the present application, optionally, the orthogonal projections of the concavities a in the same row on the reference plane R are equal in area; the maximum pitch of any two recesses a in any two adjacent rows in the direction in which the first side s1 points toward the second side s2 is smaller closer to the second side s2 of the pole piece 231.
By controlling the change rule of the sizes of the concave parts a to be sequentially reduced and/or the change rule of the maximum spacing to be sequentially reduced, the required distribution density in the unit area of the concave parts a is conveniently obtained, and the change rule of the distribution density in the unit area of the concave parts a is controlled to be sequentially increased, so that the required pressure difference is conveniently obtained. Of course, in the above case, it is understood that the change rule of the distribution density in the unit area region of the concave portion a may be controlled to be another increasing rule such as a stepwise increase.
According to some embodiments of the present application, optionally, the orthographic projection areas of the concavities a in the same row on the reference plane R are equal; in the direction in which the first side s1 points towards the second side s2, the area of the orthographic projection of the recesses a in each row on the reference plane R decreases linearly. According to some embodiments of the present application, optionally, the orthogonal projections of the concavities a in the same row on the reference plane R are equal in area; the maximum pitch of any two recesses a in any two adjacent rows in the direction in which the first side s1 points to the second side s2 decreases linearly.
By controlling the change rule of the size of the concave portion a to be linear reduction and/or the change rule of the maximum distance to be linear reduction, the required distribution density in the unit area of the concave portion a is conveniently obtained, the change rule of the distribution density in the unit area of the concave portion a is also favorably controlled to be linear increase, and the required pressure difference is conveniently obtained through control. Of course, in the above case, it is understood that the change rule of the distribution density in the unit area region of the concave portion a may be controlled to be another increasing rule such as a stepwise increase.
According to some embodiments of the present application, optionally, with continuing reference to fig. 9 in combination with fig. 5, the orthographic projection areas of all the recesses a on the reference plane R are equal; the maximum pitch between any two recesses a in any adjacent two rows decreases in a direction in which the first side s1 is directed toward the second side s 2.
By controlling the sizes of the concave portions a to be the same and the variation tendency of the pitch to be a decreasing tendency, it is convenient to obtain a desired distribution density per unit area of the concave portions a, and thus to control to obtain a desired pressure difference. It will be appreciated that the orthogonal projections of all the recesses a on the reference plane R have equal areas, which also facilitates the fabrication of the recesses a.
According to some embodiments of the present application, optionally, with continuing reference to fig. 9 in combination with fig. 5, the orthographic projection areas of all the recesses a on the reference plane R are equal; the maximum pitch of any two recesses a in any two adjacent rows in the direction in which the first side s1 points toward the second side s2 is smaller closer to the second side s2 of the pole piece 231.
By controlling the change rule of the maximum distance to be sequentially reduced, the required distribution density in the unit area region of the concave portion a is conveniently obtained, and the change rule of the distribution density in the unit area region of the concave portion a is controlled to be sequentially increased, so that the required pressure difference is conveniently obtained. Of course, in the above case, it is understood that the change rule of the distribution density in the unit area region of the concave portion a may be controlled to be another increasing rule such as a stepwise increase.
According to some embodiments of the present application, optionally, with continuing reference to fig. 9 in combination with fig. 5, the orthographic projection areas of all the recesses a on the reference plane R are equal; the maximum pitch of any two recesses a in any two adjacent rows decreases linearly in the direction in which the first side s1 points toward the second side s 2.
By controlling the change rule of the maximum distance to be linear reduction, the required distribution density of the concave part a in the unit area is conveniently obtained, and the change rule of the distribution density of the concave part a in the unit area is controlled to be linear increase, so that the required pressure difference is conveniently obtained. Of course, in the above case, the change rule of the distribution density in the unit area region of the concave portion a may be controlled to be another increase rule such as a stepwise increase.
According to some embodiments of the present application, optionally, the maximum spacing of any two recesses a in any two adjacent rows in the direction in which the first side s1 points to the second side s2 is equal.
By controlling the maximum spacing to be equal and adjusting the size of the concave part a, the required distribution density in the unit area of the concave part a can be conveniently obtained, and the required pressure difference can be conveniently obtained through control.
Thus, in some of the above embodiments, some arrangements are exemplarily shown when the plurality of recesses a are arranged in a plurality of rows in the first preset direction on the surface on which they are located. It is understood that, when the arrangement of the concave portions a is arranged in a plurality of rows, in order to obtain the required distribution density of the concave portions a in the unit area, the method illustrated in some embodiments is used, but not limited to.
According to some embodiments of the present application, optionally, please continue to refer to fig. 6 to 8, the plurality of concave portions a are arranged in a plurality of rows on the surface thereof along the direction from the first side s1 to the second side s 2. The size of the recesses a in the same row may be the same or different. The distances between two adjacent recesses a in the same row along the direction from the first side s1 to the second side s2 may be the same or different. The spacing between the columns may be the same or different. The method can be set according to actual use conditions, and the method is not particularly limited in the embodiment of the application.
In this way, the plurality of rows are arranged in the direction from the first side s1 to the second side s2, which not only facilitates controlling the distribution density in the unit area of the recess a, but also facilitates manufacturing and molding.
According to some embodiments of the present application, optionally, with continued reference to fig. 6 to 8, along the direction from the first side s1 to the second side s2, the area of the orthographic projection of the concave portions a in the same column on the reference plane R increases.
The size of the concave part a is controlled to be increased, so that the required distribution density of the concave part a in a unit area is conveniently obtained, and the required pressure difference is further conveniently obtained.
According to some embodiments of the present application, optionally, please continue to refer to fig. 6 to 8, the area of the orthographic projection of the recesses a in the same column on the reference plane R is larger closer to the second side s2 of the pole piece 231.
By controlling the change rule of the sizes of the concave portions a in the same row to be sequentially increased, the required distribution density in the unit area region of the concave portions a can be conveniently obtained, and the change rule of the distribution density in the unit area region of the concave portions a can be controlled to be sequentially increased, so that the required pressure difference can be conveniently obtained.
According to some embodiments of the present application, optionally, with continued reference to fig. 6 to 8, the area of the orthographic projection of the recesses a in the same column on the reference plane R increases linearly along the direction from the first side s1 to the second side s 2.
By controlling the change rule of the sizes of the concave portions a in the same row to be linearly increased, the required distribution density of the concave portions a in the unit area can be conveniently obtained, and the change rule of the distribution density of the concave portions a in the unit area can be controlled to be linearly increased, so that the required pressure difference can be conveniently obtained. Of course, in the above case, it is understood that the change rule of the distribution density in the unit area region of the concave portion a may be controlled to be another increasing rule such as a stepwise increase.
According to some embodiments of the present application, optionally, please continue to refer to fig. 6 to 8, two adjacent recesses a in the same column are equally spaced in a direction in which the first side s1 points to the second side s 2.
By controlling the equal spacing between two adjacent concave parts a in the same row and adjusting the size of the concave parts a, the required distribution density of the concave parts a in a unit area can be conveniently obtained, and the required pressure difference can be conveniently obtained. Of course, the distance between two adjacent concave portions a in the same column may also decrease or increase in the direction from the first side s1 to the second side s2, as long as the required distribution density in the unit area of the concave portions a can be obtained, which is not particularly limited by the embodiment of the present application.
According to some embodiments of the present application, optionally, along the direction from the first side s1 to the second side s2, the area of the orthographic projection of the concave parts a in the same column on the reference plane R is in a decreasing trend; the distance between two adjacent recesses a in the same column decreases in the direction in which the first side s1 points to the second side s 2.
By controlling the trend of the variation of the sizes of the concave portions a in the same row to be a decreasing trend and the trend of the variation of the pitch between two adjacent concave portions a in the same row to be a decreasing trend, a desired distribution density per unit area of the concave portions a can be obtained, and thus a desired pressure difference can be obtained.
According to some embodiments of the present application, optionally, along the direction in which the first side s1 points to the second side s2, the area of the orthographic projection of the recesses a in the same column on the reference plane R is smaller closer to the second side s2 of the pole piece 231. According to some embodiments of the present application, optionally, the spacing between two adjacent recesses a in the same column in the direction in which the first side s1 points to the second side s2 is smaller closer to the second side s2 of the pole piece 231.
By controlling the change rule of the sizes of the concave parts a in the same row to be sequentially reduced and/or controlling the change rule of the distances between two adjacent concave parts a in the same row to be sequentially reduced, the required distribution density in the unit area of the concave parts a can be conveniently obtained, and the change rule of the distribution density in the unit area of the concave parts a can be favorably controlled to be sequentially increased, so that the required pressure difference can be conveniently obtained through control. Of course, in the above case, it is understood that the change rule of the distribution density in the unit area region of the concave portion a may be controlled to be another increasing rule such as a stepwise increase.
According to some embodiments of the present application, optionally, along the direction in which the first side s1 points to the second side s2, the area of the orthographic projection of the recesses a in the same column on the reference plane R decreases linearly. According to some embodiments of the present application, optionally, the spacing between two adjacent recesses a in the same column decreases linearly in the direction in which the first side s1 points to the second side s 2.
By controlling the change rule of the sizes of the concave parts a in the same row to be sequentially reduced and/or controlling the change rule of the distance between two adjacent concave parts a in the same row to be linearly reduced, the required distribution density of the concave parts a in a unit area region can be conveniently obtained, the change rule of the distribution density of the concave parts a in the unit area region can be favorably controlled to be linearly increased, and the required pressure difference can be conveniently obtained through control. Of course, in the above case, it is understood that the change rule of the distribution density in the unit area region of the concave portion a may be controlled to be another increasing rule such as a stepwise increase.
According to some embodiments of the present application, optionally, the orthographic projection areas of the recesses a in the same column on the reference plane R are equal; the distance between two adjacent recesses a in the same column decreases in the direction in which the first side s1 points to the second side s 2.
By controlling the sizes of the concave portions a in the same row to be the same and the variation trend of the distance between two adjacent concave portions a in the same row to be a decreasing trend, the required distribution density in the unit area of the concave portions a can be conveniently obtained, and the required pressure difference can be conveniently obtained.
According to some embodiments of the present application, optionally, the spacing between two adjacent recesses a in the same column in the direction in which the first side s1 points to the second side s2 is smaller closer to the second side s2 of the pole piece 231.
On the basis that the sizes of the concave parts a in the same row are the same, the change rule of the distance between two adjacent concave parts a in the same row is controlled to be sequentially reduced, so that the required distribution density in the unit area of the concave parts a is conveniently obtained, the change rule of the distribution density in the unit area of the concave parts a is also controlled to be sequentially increased, and the required pressure difference is conveniently obtained through control. Of course, in the above case, it is understood that the change rule of the distribution density in the unit area region of the concave portion a may be controlled to be another increasing rule such as a stepwise increase.
According to some embodiments of the present application, optionally, the spacing between two adjacent recesses a in the same column decreases linearly in the direction in which the first side s1 points to the second side s 2.
On the basis that the sizes of the concave parts a in the same row are the same, the change rule of the distance between two adjacent concave parts a in the same row is controlled to be linearly reduced, so that the required distribution density of the concave parts a in a unit area is conveniently obtained, the change rule of the distribution density of the concave parts a in the unit area is also favorably controlled to be linearly increased, and the required pressure difference is conveniently obtained. Of course, in the above case, it is understood that the change rule of the distribution density in the unit area region of the concave portion a may be controlled to be another increasing rule such as a stepwise increase.
According to some embodiments of the present application, optionally, please continue to refer to fig. 6 to 8, two adjacent recesses a in the same column are equally spaced in a direction in which the first side s1 points to the second side s 2.
By controlling the equal distance between two adjacent concave parts a in the same column and combining with the control of the size of the concave parts a, the required distribution density in the unit area of the concave parts a is conveniently obtained, and further the required pressure difference is conveniently obtained by control.
Thus, in some of the above embodiments, some arrangements of the plurality of recesses a arranged in a plurality of rows along the first predetermined direction of the pole piece 231 on the surface thereof are exemplified. It is understood that, when the arrangement of the concave portions a is arranged in a plurality of rows, in order to obtain the required distribution density of the concave portions a in the unit area, the method illustrated in some embodiments above is used, but not limited to.
According to some embodiments of the present application, optionally, with continued reference to fig. 7 and 8, the plurality of recesses a are arranged in an array along the first direction F1 and the second direction F2 on the surface on which they are located. The first direction F1 intersects the second direction F2. That is, the first direction F1 and the second direction F2 are not parallel to each other, and the first direction F1 and the second direction F2 are disposed at an angle. The angle between the first direction F1 and the second direction F2 may be 30 °, 45 °, 80 °, 88 °, 120 °, 150 °, etc. The method can be set according to actual use conditions, and the method is not particularly limited in the embodiment of the application. Fig. 7 and 8 illustrate a case where the first direction F1 and the second direction F2 are perpendicular to each other.
It should be noted that the array includes, but is not limited to, a rectangular array, a parallelogram array, and the like. For example, when the angle between the first direction F1 and the second direction F2 is 90 °, the array formed is a rectangular array as illustrated in fig. 7 and 8. For another example, when the angle between the first direction F1 and the second direction F2 is 80 °, the array formed is a parallelogram array.
By further controlling the arrangement of the concave portions a, that is, arranging the concave portions a in an array form forming a plurality of rows in two directions, not only the required distribution density per unit area of the concave portions a is facilitated, but also the manufacturing molding is facilitated.
According to some embodiments of the present application, optionally, with continued reference to fig. 8, the plurality of concave portions a are arranged on the surface thereof in a plurality of rows (i.e., the aforementioned horizontal rows) along the first direction F1 and in a plurality of columns (i.e., the aforementioned vertical rows) along the second direction F2; the first direction F1 and a direction of the first side s1 pointing to the second side s2 are parallel to each other, and the second direction F2 and the first predetermined direction are parallel to each other. That is, the plurality of concave portions a are arranged in an array on the surface on which they are formed. Fig. 8 illustrates a case where the direction from the first side s1 to the second side s2 is parallel to the width direction W, and the first predetermined direction and the length direction L are parallel to each other, in other words, the first direction F1 and the width direction W are parallel to each other, and the second direction F2 and the length direction L of the pole piece 231 are parallel to each other. Fig. 7 illustrates a case where the first direction F1 is disposed at an angle to the width direction W, and the second direction F2 is disposed at an angle to the longitudinal direction L of the pole piece 231. In the case illustrated in fig. 7, the rows are all diagonal rows as previously described.
By controlling the arrangement of the plurality of concave portions a on the surface thereof in a plurality of rows and columns in the width direction W and the length direction L, it is possible to further facilitate obtaining a desired distribution density per unit area region of the concave portions a and manufacturing molding.
According to some embodiments of the present application, optionally, please continue to refer to fig. 8, the pitches (i.e., the third pitches d 3) between two adjacent recesses a in the same row in the length direction L are equal. According to some embodiments of the present application, optionally, the intervals between two adjacent recesses a in the same column in the width direction W are equal (i.e., the second interval d 2).
On one hand, the size of the concave part a is convenient to control by controlling the distance between two adjacent concave parts a in the same row and the distance between two adjacent concave parts a in the same column, so that the required distribution density of the concave parts a in a unit area is obtained; on the other hand, the manufacturing and molding are also convenient. In the case where the pitches between two adjacent recesses a in the same row in the longitudinal direction L are equal and the pitches between two adjacent recesses a in the same column in the width direction W are equal, it is more convenient to control the sizes of the recesses a so as to obtain a desired distribution density per unit area region of the recesses a.
According to some embodiments of the present application, optionally, with continued reference to fig. 8 and 10, along the direction from the first side s1 to the second side s2, the area of the orthographic projection of the concave portion a in the same column on the reference plane R increases.
By controlling the trend of the change of the concave portions a in the same row to be an increasing trend, the required distribution density of the concave portions a in the unit area region can be conveniently obtained, and the required pressure difference can be conveniently obtained.
According to some embodiments of the present application, optionally, with continued reference to fig. 8 and 10, along the direction in which the first side s1 points to the second side s2, the area of the orthographic projection of the recesses a in the same column on the reference plane R is larger closer to the second side s2 of the pole piece 231.
By controlling the change rule of the concave parts a in the same column to be sequentially increased, the required distribution density of the concave parts a in the unit area is conveniently obtained, the required change rule of the distribution density of the concave parts a in the unit area is conveniently controlled to be sequentially increased, and the required pressure difference is conveniently obtained. Of course, in the above case, it is understood that the change rule of the distribution density in the unit area region of the concave portion a may be controlled to be another increasing rule such as a stepwise increase.
According to some embodiments of the present application, optionally, with continued reference to fig. 8 and 10, the area of the orthographic projection of the recesses a in the same column on the reference plane R increases linearly along the direction from the first side s1 to the second side s 2.
By controlling the change rule of the concave portions a in the same column to be linearly increased, not only is it convenient to obtain the required distribution density in the unit area of the concave portions a, but also it is convenient to control the change rule of the required distribution density in the unit area of the concave portions a to be linearly increased, and further it is convenient to control to obtain the required pressure difference. Of course, in the above case, the change rule of the distribution density in the unit area region of the concave portion a may be controlled to be another increase rule such as a stepwise increase.
According to some embodiments of the present application, optionally, with continuing reference to fig. 8 and 10, the shape of the orthographic projection of the recess a on the reference plane R includes at least one of a polygon, a circle, an ellipse. The polygons may be triangles, rectangles, trapezoids, and the like.
In this manner, the distribution density per unit area of the concave portion a can be obtained by structuring the shape of the concave portion a.
According to some embodiments of the application, optionally, the area of the orthographic projection of the recess a on the reference plane R is 1mm 2 To 100mm 2 . That is, the area of the orthographic projection of the concave portion a on the reference plane R may be 1mm 2 To 100mm 2 Can be, but is not limited to, 1mm 2 、2 mm 2 、5 mm 2 、20mm 2 、30mm 2 、40 mm 2 、70 mm 2 、90mm 2 、100 mm 2 And the like.
By controlling the size of the recess a, it is possible to obtain a desired distribution density per unit area of the recess a, and it is possible to prevent the reliability of the pole piece 231 from being affected by an excessively large or excessively small recess a.
Thus, in some of the above embodiments, some arrangements of the plurality of recesses a arranged in a plurality of rows and/or columns along the first predetermined direction on the surface thereof are exemplarily shown. It will be appreciated that when the arrangement of the concave portions a is arranged in a plurality of rows and/or a plurality of columns, in order to obtain the desired distribution density in the unit area of the concave portions a, the method includes, but is not limited to, the method illustrated in some of the above embodiments.
According to some embodiments of the present application, optionally, please refer to fig. 11 and 12, where fig. 11 is a schematic structural diagram of the pole piece 231 in other embodiments of the present application, and fig. 12 is a schematic structural diagram of the pole piece 231 in still other embodiments of the present application. The plurality of concave portions a are arranged along a second preset direction, and the concave portions a comprise starting ends a1 and terminating ends a2. The second predetermined direction is not parallel to the width direction W, the direction of the starting end a1 pointing to the terminating end a2 is not parallel to the first predetermined direction, and the direction of the first side s1 pointing to the second side s2, the first predetermined direction, and the thickness direction δ of the pole piece 231 are perpendicular to each other. The sizes of the respective recesses a may be the same or different.
The recess a can be easily produced by configuring the shape of the recess a to have a substantially constant length.
According to some embodiments of the present application, optionally, referring to fig. 11 and 12, the second predetermined direction and the first predetermined direction are parallel to each other; and/or the direction in which the starting end a1 points to the terminating end a2 and the width direction W are parallel to each other. Taking fig. 11 and 12 as an example, a case is illustrated in which the direction from the first side s1 to the second side s2 is parallel to the width direction W, and the first predetermined direction and the longitudinal direction L are parallel to each other, that is, the general extending direction of the concave portion a is the width direction W, and the arrangement direction is the longitudinal direction L. The directions illustrated in fig. 11 and 12 will not be described in detail later. For example, in the case where the starting end a1 of the recess a is closer to the first side s1 of the pole piece 231 and the terminating end a2 of the recess a is closer to the second side s2 of the pole piece 231, a structure similar to a longitudinal shape may be formed, that is, the dimension C of the recess a in the length direction L is smaller than the dimension C of the recess a in the width direction W. The cross section of the concave portion a in the width direction W may be a C shape as shown in fig. 13, may also be an arc shape as shown in fig. 14, and may of course be other shapes, and may be provided according to actual use conditions, which is not particularly limited in the embodiment of the present application.
This facilitates not only the production of the recesses a but also the desired distribution density of the recesses a per unit area.
According to some embodiments of the present application, optionally, please refer to fig. 15 in combination with fig. 12, fig. 15 is a schematic view of a third projection y3 in some embodiments of the present application, and a second projection y2 in fig. 15 is an orthographic projection of the concave portion a illustrated in fig. 12 on the reference plane R. In a direction from the first side s1 to the second side s2, a dimension C of the recess a in the first predetermined direction increases. That is, the size C of the orthographic projection of the concave portion a on the reference surface in the first preset direction tends to increase, and the orthographic projection tends to increase in a direction from the first side s1 to the second side s 2. Fig. 15 illustrates a case where the direction from the first side s1 to the second side s2 is parallel to the width direction W, and the first predetermined direction and the length direction L are parallel to each other.
By controlling the trend of the variation of the dimension C of the concave portion a along the first preset direction to be an increasing trend, it is convenient to obtain a desired trend of the distribution density within the unit area of the concave portion a.
According to some embodiments of the present application, optionally, with continued reference to fig. 11 and 12, a dimension C of the recess a along the first preset direction is larger closer to the second side s2 of the pole piece 231 along a direction in which the first side s1 points to the second side s 2.
By controlling the change rule of the size C of the concave part a along the first preset direction to be sequentially increased, the distribution density in the unit area of the concave part a with the sequentially increased change rule is convenient to obtain. Of course, in the above case, it is understood that the change rule of the distribution density in the unit area region of the concave portion a may be controlled to be another increasing rule such as a stepwise increase.
According to some embodiments of the present application, optionally, with continued reference to fig. 11 and 12, a dimension C of the concave portion a along the first preset direction increases linearly along a direction from the first side s1 to the second side s 2.
By controlling the change rule of the dimension C of the concave portion a along the first preset direction to be linearly increased, the distribution density of the concave portion a in the unit area with the linearly increased change rule is conveniently obtained. Of course, in the above case, it is understood that the change rule of the distribution density in the unit area region of the concave portion a may be controlled to be another increasing rule such as a stepwise increase.
According to some embodiments of the present application, optionally, with continued reference to fig. 11 and 12, a maximum dimension C of the recess a in the first predetermined direction max A minimum dimension C of the recess a along a first predetermined direction min The ratio of (A) to (B) is 1.1 or more. That is, the maximum dimension C of the recess a in the first predetermined direction max A minimum dimension C of the recess a along a first predetermined direction min The ratio of (a) may be in a range of 1.1 or more, for example, but not limited to, 1.1, 1.2, 3, 4, 6, 8, 10, etc. The upper limit of the ratio is limited by the shape of the recess a, the width of the pole piece 231, and the like, and may be set according to the specific use condition, which is not particularly limited in the embodiment of the present application.
Therefore, the problem that the ratio is too small and the requirement for forming enough pressure difference in the channel is difficult to meet can be avoided, and the effect of gas exhaust is further influenced.
According to some embodiments of the present application, optionally, with continued reference to fig. 11 and 12, the recess a is provided extending in a straight line between the starting end a1 and the terminating end a2.
By configuring the recesses a extending linearly in this manner, not only the required distribution density per unit area region can be obtained, but also the molding and manufacturing of the recesses a can be facilitated.
According to some embodiments of the present application, optionally, with continued reference to fig. 12, the extending direction of the recess a and the direction of the first side s1 pointing to the second side s2 are parallel to each other. At this time, the extending direction of the concave portion a may also be regarded as a direction in which the starting end a1 is directed to the terminating end a2. When the extending direction of the concave portion a and the direction in which the first side s1 is directed toward the second side s2 are parallel to each other, it is more convenient to obtain a desired distribution density per unit area region. Fig. 11 illustrates a case where the direction from the first side s1 to the second side s2 and the width direction W are parallel to each other, and the extending direction of the concave portion a and the width direction W are arranged at an angle.
According to some embodiments of the present application, optionally, referring to fig. 16, fig. 16 is a schematic structural diagram of a pole piece 231 in still other embodiments of the present application, and a concave portion a is disposed along a curve extending between a starting end a1 and a terminating end a2. In this way, by constructing the concave portions a extending in a curved line, it is possible to obtain a desired distribution density per unit area region, and to mold and manufacture the concave portions a.
Of course, the configuration of the concave portion a extending between the starting end a1 and the terminating end a2 includes, but is not limited to, the above-mentioned concave portion a extending along a straight line or a curved line between the starting end a1 and the terminating end a2, and may also extend along another form such as a broken line, as long as the required distribution density in the unit area region can be obtained, which is not particularly limited by the embodiment of the present application.
According to some embodiments of the present application, optionally, with continuing reference to fig. 4 and with combined reference to fig. 13 and 14, the pole piece 231 includes a current collector 2311 and an active layer 2312, the current collector 2311 is provided with a first surface m1 and a second surface m2 on opposite sides, and the active layer 2312 is provided on at least one of the first surface m1 and the second surface m 2; wherein the recesses a are correspondingly disposed on the active layer 2312.
The current collector 2311 is a member for carrying active materials, and mainly functions to collect current generated by the active materials to form a large current to be output to the outside. Therefore, the current collector 2311 should be in sufficient contact with the active material, and the internal resistance should be preferably as small as possible. The current collector 2311 may be different according to active materials carried. For example, the current collector 2311 may be a copper foil when carrying a negative active material, and the current collector 2311 may be an aluminum foil when carrying a positive active material.
The current collector 2311 may be a single layer member (e.g., aluminum foil, copper foil), or a composite layer member. When the current collector 2311 is a composite layer member, the current collector 2311 may include an intermediate layer and two current collecting metal layers stacked on both sides of the intermediate layer, and the active material is supported on a side of the current collecting metal layer opposite to the intermediate layer. The intermediate layer may be a polymer support layer, specifically a polyethylene support layer, a polypropylene support layer, a polymethyl methacrylate support layer, a polystyrene support layer, or the like.
The active layer 2312 is typically formed by cold pressing after a slurry containing active material is applied to the current collector 2311. The active layer 2312 of different polarity contains different active materials. When the active layer 2312 is a negative active layer, the active material contained therein is a negative active material, such as a carbon negative material, a tin-based negative material, a lithium-containing transition metal nitride negative material, an alloy negative material, a nano-scale negative material, and the like. When the active layer 2312 is a positive active layer, the active material contained therein is a positive active material, such as lithium iron phosphate, lithium manganate, lithium cobaltate, ternary nickel cobalt manganese material, lithium nickel cobalt aluminate, and the like. In some embodiments, a polymer coating may also be provided on the surface of the current collector 2311 where the active layer 2312 is desired to increase the adhesion between the active layer 2312 and the current collector 2311.
Opposite sides of the current collector 2311 are opposite sides of the current collector 2311 in the thickness direction δ. The first surface m1 and the second surface m2 of the current collector 2311 may be covered with an active layer 2312, and the polarities of the active layers 2312 at both sides may be the same or different. The active layer 2312 may be coated on the first surface m1 or the second surface m2 of the current collector 2311. In general, two active layers 2312, which are disposed on opposite sides of the current collector 2311 in the thickness direction δ, have opposite polarities, one being a positive electrode active layer and the other being a negative electrode active layer.
The recess a is correspondingly disposed on the active layer 2312, that is, when the recess a is disposed on the first surface m1 of the current collector 2311, the active layer 2312 is disposed on the first surface m1 of the current collector 2311, and the recess a is disposed on the side of the active layer 2312 facing away from the current collector 2311. Similarly, when the second surface m2 of the current collector 2311 is provided with the concave a, the second surface m2 of the current collector 2311 is provided with the active layer 2312, and the concave a is arranged on the side, away from the current collector 2311, of the active layer 2312.
So, through forming concave part a on active layer 2312, not only can avoid causing the damage to mass collector 2311, reduce the cracked risk of electrode subassembly 23, can also avoid bringing the compaction difference, and then avoid influencing electric core performance.
According to some embodiments of the present application, optionally, with continued reference to fig. 13 and 14, the ratio of the depth h1 of the recess a to the thickness h2 of the active layer 2312 in which it is located is one-third to three-quarters. It is understood that the depth h1 of the recess a refers to the dimension C of the recess a in the thickness direction δ. The ratio of the depth h1 of the recess a to the thickness h2 of the active layer 2312 in which the recess a is located may be between one third and three quarters, for example, but not limited to, one third, two thirds, one quarter, two quarters, three quarters, etc.
If the depth h1 of the concave portion a is too low, the formation of the active layer 2312 through a step such as cold pressing may cause the concave portion a to be flattened out and fail to form a sufficient pressure difference for exhausting. In addition, since the active layer 2312 expands after the first formation of the battery 100, and the depth h1 of the recess a becomes low, it is difficult to form a sufficient pressure difference and a gas passage of a certain size even when the depth h1 of the recess a is too low. If the depth h1 of the recess a is too high, the active particles in the active layer 2312 may be broken to affect the electrical performance of the pole piece 231.
Thus, it is avoided that the depth h1 of the recess a is too low to form a sufficient pressure difference for exhausting, and that the depth h1 of the recess a is too high to affect the electrical performance of the pole piece 231.
According to some embodiments of the present application, optionally, with continued reference to fig. 13 and 14, the depth h1 of the recess a is 0.1mm to 2mm. That is, the depth h1 of the recess a may be between 0.1mm and 2mm, for example, but not limited to, 0.1mm, 0.3mm, 0.5mm, 1.5mm, 1.8mm, 2mm, etc.
In this manner, the depth h1 of the recess a is further set to a size so as to form a sufficient pressure difference.
According to some embodiments of the present application, please refer to fig. 17 and fig. 18, fig. 17 is a schematic structural view of a roller g in some embodiments of the present application at one viewing angle, fig. 18 is a schematic structural view of the roller g in some embodiments of the present application at another viewing angle, fig. 17 and fig. 18 are relatively speaking, the viewing angle of fig. 17 is a perspective viewing angle, and the viewing angle of fig. 18 is a front view of fig. 17. The application also provides a roller piece g, wherein a plurality of convex parts t are arranged on the peripheral surface of the roller piece g; when the roller g is rolled on the pole piece 231 to be processed, a plurality of concave portions a can be formed on the surface of the pole piece 231 to be processed by a plurality of convex portions t, and the pole piece 231 in any of the above schemes can be formed.
The roller g means a body of revolution having a central axis about which it can rotate. The outer peripheral surface of the roller g means an outer peripheral surface located in the radial direction of the roller g. The convex portion t is a structure that is convex to the outer peripheral surface of the roller g. The pole piece 231 to be processed refers to the pole piece 231 not yet provided with the recess a.
It is understood that the shape of the convex portion t corresponds to the shape of the concave portion a. For example, when the shape of the orthographic projection of the concave portion a on the reference plane R is circular, the shape of the cross section of the convex portion t in the convex direction thereof is also circular; when the shape of the orthographic projection of the concave portion a on the reference plane R is a rectangle, as shown in fig. 17 and 18, the shape of the cross section of the convex portion t in the convex direction thereof is also a rectangle; when the concave portion a has a vertically long configuration, as shown in fig. 19 and 20, the convex portion t also has a vertically long configuration, and the roller g shown in fig. 19 corresponds to the pole piece 231 shown in fig. 12, and the roller g shown in fig. 20 corresponds to the pole piece 231 shown in fig. 16. When the sizes of the plurality of recesses a in the pole piece 231 are different, the sizes of the plurality of projections t are set to be different. Similarly, the arrangement of the convex portions t corresponds to the concave portions a, and reference may be made to the foregoing embodiments related to the arrangement of the concave portions a, which are not repeated herein.
In the manufacturing process of forming the pole piece 231 in any of the above embodiments, the roller g presses the active layer 2312 of the pole piece 231 under a certain pressure, so as to form the required recess a on the active layer 2312 of the pole piece 231.
It should be noted that, since the pole piece 231 in any of the above schemes is manufactured by using the roller g, the pole piece 231 has the advantages mentioned above, and details are not described herein.
According to some embodiments of the present application, there is also provided a rolling device comprising a roll member g according to any of the above aspects. It should be noted that, since the rolling device includes the roller g in any of the above schemes, the pole piece 231 in any of the above schemes can be manufactured, and the pole piece 231 has the advantages described above, which is not described herein again.
Referring to fig. 21, fig. 21 is a schematic structural diagram of an electrode assembly 23 according to some embodiments of the present disclosure, and the present disclosure further provides an electrode assembly 23 including a positive electrode tab 231a, a negative electrode tab 231b, and a separator 232 disposed between the positive electrode tab 231a and the negative electrode tab 231 b; the positive electrode tab 231a and/or the negative electrode tab 231b is the tab 231 of any of the above embodiments. Since the electrode assembly 23 includes the pole piece 231 of any of the above embodiments, the pole piece 231 has the advantages as mentioned above, and will not be described herein.
According to some embodiments of the present application, a concave portion a may be optionally provided on the positive electrode tab 231a, which may reduce production costs. Of course, according to other embodiments of the present application, the negative electrode tab 231b may be optionally provided with the recess a according to related requirements. The setting can be carried out according to the actual use requirement, and the embodiment of the application does not specifically limit the setting.
According to some embodiments of the present application, optionally, the electrode assembly 23 is a coiled structure. In this way, the electrode assembly 23 of a winding type structure may be selectively used according to the use requirement.
According to some embodiments of the present application, optionally, the electrode assembly 23 is a laminated structure. As such, the electrode assembly 23 of the stacked-sheet type structure may be selectively used according to the use requirements.
According to some embodiments of the present application, there is also provided a battery cell 20 including a case 22 and an electrode assembly 23 as in any one of the above, the electrode assembly 23 being housed within the case 22. Since the battery cell 20 includes the electrode assembly 23 in any of the above embodiments, and the electrode assembly 23 includes the pole piece 231 in any of the above embodiments, the pole piece 231 has the advantages as mentioned above, and is not described herein again.
According to some embodiments of the present application, the present application also provides a battery 100 including the battery cell 20 of any one of the above aspects. Since the battery 100 includes the battery cell 20 in any of the above embodiments, the battery cell 20 includes the electrode assembly 23 in any of the above embodiments, the electrode assembly 23 includes the pole piece 231 in any of the above embodiments, and the pole piece 231 has the advantages as mentioned above, which is not described herein again.
According to some embodiments of the present application, the present application further provides an electric device, which includes the battery 100 of any of the above aspects, and the battery 100 is used for providing electric energy.
The powered device may be any of the aforementioned devices or systems that employ battery 100.
With continued reference to fig. 12 and 13, according to some embodiments of the present application, a pole piece 231 is provided, the pole piece 231 including a current collector 2311 and an active layer 2312. Opposite sides of the current collector 2311 are provided with a first surface m1 and a second surface m2. The active layer 2312 is provided on at least one of the first surface m1 and the second surface m2. The recess a is correspondingly provided on the active layer 2312. The plurality of concave portions a are arranged in a plurality of rows in the width direction W and a plurality of columns in the length direction L on the surface thereof. The pitches between two adjacent recesses a in the same row in the longitudinal direction L are equal, and the pitches between two adjacent recesses a in the same column in the width direction W are equal. The area of the orthographic projection of the recesses a in the same column on the reference plane R increases linearly along the direction in which the first side s1 points to the second side s 2. The orthogonal projections of the concavities a in the same row on the reference plane R have the same area. The area ratio difference in the target unit area region is 10% to 35%, and the total area ratio of the plurality of concave portions a on the surface thereof is 40% to 75%. The area ratio difference in the target unit area region is the difference between the minimum area ratio in the unit area of the recessed portion a and the maximum area ratio in the unit area of the recessed portion a. The depth h1 of the recess a is 0.1mm to 2mm.
Therefore, the channels formed by the pole pieces 231 and the corresponding spacers 232 increase linearly in the direction from the first side s1 to the second side s2, and as the electrode assembly 23 expands during the charging process of the battery 100, the channels are compressed, and the pressure applied to the positions with larger space in the channels is smaller, while the pressure applied to the positions with smaller space in the channels is larger, so that the pressure generated in the channels decreases linearly in the direction from the first side s1 to the second side s2 to generate a pressure difference. The generated gas is facilitated to be discharged in a direction in which the first side s1 is directed toward the second side s2, that is, from a structure such as a liquid injection hole provided on the top of the battery cell 20, via the passage under the action of the pressure difference. In this process, also due to the equal spacing between two adjacent recesses a in the same row in the first predetermined direction, and the pressure difference existing in the direction from the first side s1 to the second side s2, it is more helpful to force the gas from the channel into the channel along both sides in the first predetermined direction. Therefore, by controlling the plurality of concave portions a to be distributed in an array on the surface of the battery 100, the manufacturing and molding are facilitated, a pressure difference with a more uniform gradient can be formed, the accumulation and generation of bubbles u in the battery 100 can be avoided, the problems of black spots, lithium precipitation and the like after the battery 100 is formed are relieved, and the safety and the service life of the battery 100 are improved. In addition, in the embodiment of the present application, in combination with the structure of the pole piece 231, the active layer 2312 is disposed on the pole piece 231, so that the recess a capable of accelerating the exhaust is formed in the active layer 2312, and meanwhile, the expansion characteristic of the battery 100 itself during the charging and discharging process is utilized to generate the required pressure difference, so that no additional energy consumption or other devices are required. The pole piece 231 provided in the embodiment of the present application has a simple structure, and can improve the safety and cycle life of the battery 100 without increasing the manufacturing cost of the battery 100.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art will understand that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; these modifications and substitutions do not depart from the spirit of the embodiments of the present application, and they should be construed as being included in the scope of the claims and description of the present application. In particular, the technical features mentioned in the embodiments can be combined in any way as long as there is no structural conflict. The present application is not intended to be limited to the particular embodiments disclosed herein but is to cover all embodiments that may fall within the scope of the appended claims.

Claims (29)

1. A pole piece, characterized in that the pole piece (231) has a first surface (m 1) and a second surface (m 2) arranged opposite to each other, at least one of the first surface (m 1) and the second surface (m 2) of the pole piece (231) being provided with a plurality of recesses (a);
wherein the pole piece (231) is provided with a first side (s 1) and a second side (s 2) which are oppositely arranged, and the distribution density of the plurality of concave parts (a) in a unit area on the surface of the pole piece (231) is increased along the direction from the first side (s 1) to the second side (s 2);
the first side (s 1) points in the direction of the second side (s 2) and is parallel to the width direction (W) of the pole piece (231) or the length direction (L) of the pole piece (231); the width direction (W) and the length direction (L) are perpendicular to each other.
2. The pole piece according to claim 1, characterized in that the distribution density of the plurality of recesses (a) increases in a unit area on the surface thereof in a direction from the first side (s 1) to the second side (s 2); and/or
The distribution density of the plurality of recesses (a) in a unit area on the surface thereof increases linearly in a direction in which the first side (s 1) points toward the second side (s 2).
3. Pole piece according to claim 1, characterized in that the area fraction of the plurality of recesses (a) per unit area on the surface on which they are located is increasing in the direction from the first side (s 1) towards the second side (s 2).
4. The pole piece of claim 1, wherein the ratio between the area-to-area ratio difference within a target unit area of the indentations (a) and the total area-to-area ratio of the plurality of indentations (a) on the surface on which they are located is 0.13 to 0.875;
the area ratio difference in the target unit area region is a difference between a minimum area ratio in a unit area of the recess (a) and a maximum area ratio in a unit area of the recess (a).
5. The pole piece of claim 4 wherein the area fraction difference in the target area per unit area is 10% to 35% and the total area fraction of the plurality of indentations (a) on the surface on which they are located is 40% to 75%.
6. Pole piece according to any of claims 1 to 5, characterized in that the recesses (a) are arranged in a plurality of rows on the surface on which they are located.
7. Pole piece according to claim 6, characterized in that the connecting line (q) of all the recesses (a) of each row is a straight line, a broken line or a curved line.
8. The pole piece according to claim 6, characterized in that said plurality of recesses (a) are arranged in a plurality of rows along a first predetermined direction on the surface on which they are located, the direction of said first side (s 1) pointing towards said second side (s 2), said first predetermined direction and the thickness direction (δ) of said pole piece (231) being mutually perpendicular; or alternatively
The plurality of recesses (a) are arranged in a plurality of rows on the surface thereof in a direction in which the first side (s 1) points toward the second side (s 2).
9. The pole piece of claim 6, wherein the plurality of recesses (a) are arranged in an array along a first direction (F1) and a second direction (F2) on the surface on which they are arranged;
the first direction (F1) intersects the second direction (F2).
10. The pole piece of claim 9, wherein the plurality of recesses (a) are arranged in a plurality of rows in the first direction (F1) and a plurality of columns in the second direction (F2) on the surface thereof;
the first direction (F1) and the direction of the first side (s 1) pointing to the second side (s 2) are parallel to each other, and the second direction (F2) and a first preset direction are parallel to each other; the direction in which the first side (s 1) points towards the second side (s 2), the first predetermined direction and the thickness direction (δ) of the pole piece (231) are mutually perpendicular.
11. The pole piece according to claim 10, characterized in that the spacing between two adjacent recesses (a) in the same row in the first preset direction is equal; and/or
The distance between two adjacent recesses (a) in the same column in the direction in which the first side (s 1) points towards the second side (s 2) is equal.
12. Pole piece according to claim 10, characterized in that the area of the orthographic projection of the recesses (a) in the same column on a reference plane (R) is increasing in the direction from the first side (s 1) to the second side (s 2);
the reference plane (R) is a plane parallel to the direction in which the first side (s 1) points to the second side (s 2) and to the first preset direction.
13. The pole piece according to claim 12, characterized in that, in the direction in which the first side (s 1) points towards the second side (s 2), the area of the orthographic projection of the recesses (a) in the same column on a reference plane (R) is greater closer to the second side (s 2) of the pole piece (231); and/or
The area of the orthographic projection of the recesses (a) in the same column on a reference plane (R) increases linearly in the direction from the first side (s 1) to the second side (s 2).
14. The pole piece according to any one of claims 1 to 5, wherein the plurality of recesses (a) are arranged along a second predetermined direction, the recesses (a) comprising a starting end (a 1) and a terminating end (a 2);
the second preset direction and a direction of the first side (s 1) pointing to the second side (s 2) are not parallel to each other, a direction of the starting end (a 1) pointing to the terminating end (a 2) and a first preset direction are not parallel to each other, and a direction of the first side (s 1) pointing to the second side (s 2), the first preset direction and a thickness direction (δ) of the pole piece (231) are perpendicular to each other.
15. The pole piece of claim 14, wherein the second predetermined direction and the first predetermined direction are parallel to each other; and/or
The direction in which the starting end (a 1) points towards the terminating end (a 2) and the direction in which the first side (s 1) points towards the second side (s 2) are parallel to each other.
16. Pole piece according to claim 14, characterized in that the dimension (C) of the recess (a) in the first predetermined direction is increasing in the direction from the first side (s 1) to the second side (s 2).
17. The pole piece according to claim 16, characterized in that, along the direction in which the first side (s 1) points towards the second side (s 2), the dimension (C) of the recess (a) along the first preset direction is greater closer to the second side (s 2) of the pole piece (231); and/or
The dimension (C) of the recess (a) in the first predetermined direction increases linearly in a direction from the first side (s 1) to the second side (s 2).
18. Pole piece according to claim 16, characterized in that the maximum dimension (C) of the recess (a) in the first preset direction max ) And a minimum dimension (C) of said recess (a) along said first predetermined direction min ) The ratio of (A) to (B) is 1.1 or more.
19. Pole piece according to claim 14, characterized in that the recess (a) extends in a straight line between the starting end (a 1) and the terminating end (a 2).
20. Pole piece according to claim 19, characterized in that the direction of extension of the recess (a) and the direction of pointing the first side (s 1) towards the second side (s 2) are parallel to each other.
21. Pole piece according to claim 14, characterized in that the recess (a) is arranged extending along a curve between the starting end (a 1) and the terminating end (a 2).
22. The pole piece according to any one of claims 1 to 5, characterized in that the pole piece (231) comprises:
a current collector (2311), said first surface (m 1) and said second surface (m 2) being provided on opposite sides of said current collector (2311); and
an active layer (2312) provided on at least one of the first surface (m 1) and the second surface (m 2);
wherein the recesses (a) are respectively provided on the active layer (2312).
23. Pole piece according to claim 22, characterized in that the ratio of the depth (h 1) of the recess (a) to the thickness (h 2) of the active layer (2312) on which it is located is one third to three quarters.
24. Pole piece according to claim 23, characterized in that the depth (h 1) of the recess (a) is 0.1 to 2mm.
25. A roller member, characterized in that the outer peripheral surface of the roller member (g) is provided with a plurality of protrusions (t);
wherein the roller (g) is capable of forming a plurality of recesses (a) on the surface of the pole piece (231) to be processed by means of the plurality of protrusions (t) when rolling on the pole piece to be processed, and forming the pole piece (231) according to any one of claims 1 to 24.
26. An electrode assembly characterized by comprising a positive electrode tab (231 a), a negative electrode tab (231 b), and a separator (232) provided between the positive electrode tab (231 a) and the negative electrode tab (231 b);
the positive electrode tab (231 a) and/or the negative electrode tab (231 b) is a tab (231) according to any one of claims 1-24.
27. A battery cell, comprising:
a housing (22); and
the electrode assembly (23) of claim 26, the electrode assembly (23) being housed within the case (22).
28. A battery comprising a battery cell (20) according to claim 27.
29. An electric consumer, characterized in that it comprises a battery (100) according to claim 28, said battery (100) being intended to provide electric energy.
CN202223180676.2U 2022-11-30 2022-11-30 Pole piece, roller piece, electrode assembly, battery monomer, battery and power consumption device Active CN218548477U (en)

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CN202223180676.2U CN218548477U (en) 2022-11-30 2022-11-30 Pole piece, roller piece, electrode assembly, battery monomer, battery and power consumption device

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Application Number Priority Date Filing Date Title
CN202223180676.2U CN218548477U (en) 2022-11-30 2022-11-30 Pole piece, roller piece, electrode assembly, battery monomer, battery and power consumption device

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CN218548477U true CN218548477U (en) 2023-02-28

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