CN218827331U - Battery core and battery - Google Patents

Abstract

A battery core and a battery, wherein the battery core comprises a negative plate, a plugging piece, a diaphragm and a positive plate, the negative plate comprises a first current collector and a first active substance layer formed on the first current collector, the first active substance layer is provided with a groove, the groove penetrates through the first active substance layer and extends to the first current collector, and the groove is provided with a negative lug connected with the first current collector; the plug includes basic unit and viscose layer, the first surface of basic unit is towards first mass flow body, viscose layer bonding first surface and first active material layer, make the plug cover the recess completely, the orthographic area of viscose layer on first mass flow body is less than the orthographic area of basic unit on first mass flow body, lithium ion on the positive plate is deviate from and pass the micropore of diaphragm and when moving negative pole piece with the mode of diffusion, lithium ion can additionally imbed in the first active material layer of orthographic outside department of viscose layer, thereby can improve the circumferential N/P ratio of plug, reduce the risk of analyzing lithium at the plug periphery.

Description

Battery core and battery

Technical Field

The utility model relates to a lithium cell technical field, concretely relates to electricity core and battery.

Background

The current battery core adopts the connection of the electrode lug and the current collector, when the electrode lug is connected with the current collector, one proposal is to open a groove on the active substance layer on one side of the current collector, and the electrode lug is accommodated in the groove.

Usually, the lug is fixed on the current collector in a welded mode, when welding is carried out, welding burrs can be generated on one side of the lug, which deviates from the current collector, in order to prevent burrs from piercing the diaphragm, a plugging piece covering groove can be arranged on one side of the lug, which deviates from the current collector, so that lithium ions are prevented from being separated out due to the diaphragm. However, the lithium ions at the peripheral position of the pole piece on the other side corresponding to the plugging piece can still be extracted in a diffusion mode and embedded into the pole piece, so that the ratio of the negative electrode capacity per unit area to the positive electrode capacity (N/P) per unit area at the peripheral position of the pole piece is reduced, and lithium precipitation can be generated.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing an electric core and battery solves the problem of the lithium of analysing that present electric core exists.

For realizing the purpose of the utility model, the utility model provides a following technical scheme:

in a first aspect, the utility model provides an electric core, include: the negative plate comprises a first current collector and a first active substance layer formed on the first current collector, wherein the first active substance layer is provided with a groove, the groove penetrates through the first active substance layer and extends to the first current collector, and a negative tab is accommodated in the groove and connected with the first current collector; the sealing piece comprises a base layer and an adhesive layer, wherein the base layer comprises a first surface, the first surface faces the first current collector, one surface of the adhesive layer is bonded with the first surface, and the other surface of the adhesive layer is bonded with the first active material layer, so that the sealing piece completely covers the groove, and the orthographic projection area of the adhesive layer on the first current collector is smaller than that of the base layer on the first current collector; the diaphragm is stacked on the negative plate and the plugging piece; and the positive plate is stacked on one side of the diaphragm, which is back to the negative plate.

In one embodiment, the distance between the side of the orthographic projection of the adhesive layer on the first current collector and the side of the groove corresponding to the orthographic projection on the first current collector is W1, and the following requirements are met: w1 is more than or equal to 1mm and less than or equal to 5mm.

In one embodiment, the base layer further includes a second surface opposite to the first surface, an orthographic projection of the second surface on the first current collector completely covers an orthographic projection of the first surface on the first current collector, the adhesive layer is entirely located on the first surface, and at least one side of the orthographic projection of the adhesive layer on the first current collector has a spacing distance from a side of the orthographic projection of the second surface on the first current collector.

In one embodiment, at least one side of the orthographic projection of the adhesive layer on the first current collector overlaps with a side of the second surface corresponding to the orthographic projection of the second surface on the first current collector, and the remaining side of the orthographic projection of the adhesive layer on the first current collector has a spacing distance from the side of the second surface corresponding to the orthographic projection of the second surface on the first current collector.

In one embodiment, the distance between at least one edge of the orthographic projection of the adhesive layer on the first current collector and an edge corresponding to the orthographic projection of the second surface on the first current collector is W2, and the following relationship is satisfied: w2 is more than or equal to 2mm and less than or equal to 8mm.

In one embodiment, the side of the base layer is at an angle of 15 ° to 90 ° to the surface of the first active material layer facing the separator.

In one embodiment, the plugging piece further comprises a hot melt adhesive layer, the hot melt adhesive layer is arranged on the base layer back to one side of the adhesive layer, and the hot melt adhesive layer is used for bonding with the diaphragm and plugging the micropores of the diaphragm after melting.

In one embodiment, a containing groove is formed in one side, facing the diaphragm, of the positive plate, and the containing groove is opposite to the blocking piece.

In one embodiment, the depth of the accommodating groove is h1, and the thickness of the plugging piece is h2, so that: h1 is more than or equal to h2.

In a second aspect, the present invention also provides a battery including the electrical core of any one of the various embodiments of the first aspect.

The utility model discloses an electric core, through setting up the viscose layer, the orthographic projection's of viscose layer on first mass flow body area is less than the orthographic projection's of basic unit on first mass flow body area, make the viscose layer compare in the side indent of basic unit, lithium ion when on the positive plate deviates from and passes the diaphragm with the mode of diffusion when the micropore removes the negative pole piece, have partial lithium ion can imbed in the first active material layer that corresponds between the side of basic unit and the side of viscose layer, also be that it can imbed in first active material layer through the position department of viscose layer from the basic unit indent to have partial lithium ion, specifically can also additionally imbed in the orthographic projection's of basic unit inboard and in the first active material layer of the orthographic projection's of viscose layer department, thereby can improve the circumferential N/P ratio of shutoff, reduce the risk of analysing lithium at the shutoff periphery, the security of battery has been improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the description below are only some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

Fig. 1 is a schematic view of a cell in the related art;

fig. 2 is a schematic diagram of a cell of an embodiment;

FIG. 3 is a schematic view of an embodiment of a closure;

FIG. 4 is a schematic view of another embodiment of a closure;

FIG. 5 is a schematic view of another embodiment of a closure;

FIG. 6 is a bottom view of an embodiment of a closure;

fig. 7 is a schematic diagram of a cell of another embodiment.

Description of reference numerals:

10-negative electrode sheet, 11-first current collector, 12-first active material layer, 13-groove, 131-bottom wall, 132-side wall, 20-positive electrode sheet, 21-second current collector, 22-second active material layer, 23-first region, 24-containing groove, 30-diaphragm, 31-second region, 40-negative electrode tab, 50-blocking piece, 51-base layer, 511-first surface, 512-second surface, 513-side surface of base layer, 52-adhesive layer, 521-side surface of adhesive layer, 53-hot melt adhesive layer, 531-side surface of hot melt adhesive layer.

Detailed Description

The technical solutions of the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings, and obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts all belong to the protection scope of the present invention.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When a component is referred to as being "connected" to another component, it can be directly connected to the other component or intervening components may also be present.

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 invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Some embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The embodiments described below and the features of the embodiments can be combined with each other without conflict.

Referring to fig. 1, in the related art, a cell includes a negative electrode sheet 10, a separator 30 and a positive electrode sheet 20 stacked, and the cell may be formed in a cylindrical shape or a multi-roll shape by winding. The negative electrode tab 10 includes a first collector 11 and first active material layers 12 formed on both sides of the first collector 11, and the positive electrode tab 20 includes a second collector 21 and second active material layers 22 formed on both sides of the second collector 21. A groove 13 is formed in the first active material layer 12 of the first current collector 11 facing the separator 30, and the groove 13 penetrates through the first active material layer 12 and extends to the first current collector 11. Negative electrode tabs 40 are arranged in the grooves 13, and the negative electrode tabs 40 are connected with the first current collector 11 through a welding process. A blocking piece 50 is provided on the first active material layer 12 facing the separator 30, the blocking piece 50 closing the groove 13.

The second active material layer 22 on the side of the positive electrode sheet 20 facing the separator 30 has a first region 23 corresponding to the sealing material 50, and the separator 30 has a second region 31 corresponding to the sealing material 50. After the positive plate 20, the negative plate 10 and the separator 30 are compacted, the plugging piece 50 plugs the micropores of the second region 31 on the separator 30, so that the lithium ions in the first region 23 cannot penetrate through the second region 31 and the plugging piece 50 and enter the groove 13, and the burrs on the side of the negative electrode tab 40 facing away from the first current collector 11 cannot penetrate into the separator 30 due to the blocking of the plugging piece 50, so that the plugging piece 50 can protect the battery cell.

However, during charge and discharge, lithium ions at the edge of the first region 23 may be diffusively extracted and inserted into the first active material layer 12 of the negative electrode sheet 10 at the periphery of the sealing member 50, and the dotted arrow in fig. 1 gives a rough indication that lithium ions on the positive electrode sheet 20 move to the negative electrode sheet 10 at the periphery of the sealing member 50, resulting in a decrease in the N/P ratio (negative electrode capacity per unit area/positive electrode capacity per unit area) at the periphery of the sealing member 50, possibly resulting in lithium deposition.

Based on the risk of analysing lithium that exists among the correlation technique, the embodiment of the utility model provides a lithium is analysed to the problem of lithium that exists among the correlation technique of electric core improves. Referring to fig. 2 and fig. 3, an electrical core according to an embodiment of the present invention includes a negative electrode sheet 10, a positive electrode sheet 20, a separator 30, a negative electrode tab 40, and a blocking member 50.

The negative electrode tab 10 and the positive electrode tab 20 are disposed opposite to each other, and the separator 30 is disposed between the negative electrode tab 10 and the positive electrode tab 20. Specifically, the negative electrode plate 10 is provided with a groove 13, the plugging piece 50 is stacked on the negative electrode plate 10, and closes an opening of the groove 13 facing to the positive electrode plate 20, that is, an opening facing away from the first current collector 11, the diaphragm 30 is stacked on the negative electrode plate 10 and the plugging piece 50, and the positive electrode plate 20 is stacked on a side of the diaphragm 30 facing away from the negative electrode plate 10.

Negative pole piece 10 includes first mass flow body 11 and the first active material layer 12 of formation on first mass flow body 11, and first active material layer 12 is seted up flutedly 13, and flutedly 13 runs through first active material layer 12 and extends to first mass flow body 11, and recess 13 holds negative pole ear 40 of being connected with first mass flow body 11.

The first current collector 11 may be in a sheet shape, two opposite sides of the first current collector are provided with a first active material layer 12, the groove 13 is opened on the first active material layer 12 of the first current collector 11 facing one side of the diaphragm 30, and the groove 13 penetrates through the first active material layer 12. The negative tab 40 is accommodated in the groove 13, and the negative tab 40 and the first current collector 11 may be connected and fixed by bonding, welding, or the like. The bottom wall 131 of the groove 13 is the surface of the first current collector 11 on the side facing the separator 30, and the side wall 132 of the groove 13 is formed by the first active material layer 12 of the first current collector 11 on the side facing the separator 30. The first current collector 11 may be made of copper foil, and the first active material layer 12 may be made of at least one of artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based material, tin-based material, lithium titanate, and the like.

Alternatively, the thickness of the negative electrode tab 40 may be the same as the depth of the groove 13, and the negative electrode tab 40 is connected to the bottom wall 131 (i.e., the first current collector 11) of the groove 13, so that the thickness of the negative electrode tab 40 is the same as the thickness of the first active material layer 12 of the first current collector 11 facing the separator 30 and the height is flush, and thus, the blocking piece 50 is also connected to the surface of the negative electrode tab 40 facing away from the first current collector 11, and the connection stability between the blocking piece 50, the tab and the negative electrode tab 10 can be enhanced.

Optionally, the thickness of the negative electrode tab 40 may also be smaller than the depth of the groove 13, a side surface of the negative electrode tab 40 is connected to the first current collector 11, and a gap may be formed between a side surface of the negative electrode tab 40 facing away from the first current collector 11 and the plugging member 50.

The positive electrode sheet 20 has a similar structure to the negative electrode sheet 10, and the second current collector 21 may have a sheet shape, and the second active material layer 22 is disposed on two opposite sides of the second current collector. The second current collector 21 may be an aluminum foil, and the second active material layer 22 may be at least one of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt aluminum oxide and a modified compound thereof, lithium iron phosphate, a composite material of lithium iron phosphate and carbon, lithium manganese phosphate, a composite material of lithium manganese phosphate and carbon, and the like.

The closure 50 comprises a base layer 51 and an adhesive layer 52, the base layer 51 comprising opposing first and second surfaces 511, 512 and a side 513 connecting the first and second surfaces 511, 512. The first surface 511 faces the first current collector 11, and one side of the adhesive layer 52 is adhered to the first surface 511. The adhesive layer 52 adheres the first active material layer 12 around the groove 13, that is, the other side of the adhesive layer 52 is adhered to the first active material layer 12, so that the blocking piece 50 completely covers the groove 13, thereby closing the opening of the groove 13 on the side facing away from the first current collector 11. In the orthographic projection of the first current collector 11, the percentage of the area of the adhesive layer 52 in the base layer 51 is less than 100%, in other words, the area of the orthographic projection of the adhesive layer 52 on the first current collector 11 is less than the area of the orthographic projection of the base layer 51 on the first current collector 11.

The base layer 51 can be made of polyethylene terephthalate (PET), PP (polypropylene), PI (polyimide), etc., and has better electrolyte resistance, thereby avoiding adverse effects on the battery in the subsequent use process. Adhesive layer 52 may be any feasible material with adhesive properties without limitation.

Adhesive layer 52 is adhered to first active material layer 12 in the vicinity of groove 13, and adhesive layer 52 closes the opening of groove 13 on the side facing separator 30, that is, the side facing away from first current collector 11. The base layer 51 covers the adhesive layer 52 and covers a larger area than the adhesive layer 52. In actual manufacturing, the adhesive layer 52 may be coated on the first surface 511 of the base layer 51, and then the side of the base layer 51 coated with the adhesive layer 52 is covered at the groove 13, so that the adhesive layer 52 is adhered to the first active material layer 12 near the groove 13, thereby closing the opening of the groove 13 facing away from the first current collector 11 by the base layer 51 and the adhesive layer 52.

Since the orthographic projection area of the adhesive layer 52 on the first current collector 11 is smaller than the orthographic projection area of the base layer 51 on the first current collector 11, the formed sealing member 50 is concave at the position corresponding to the adhesive layer 52 on the whole side surface of the sealing member 50, that is, the adhesive layer 52 is concave from the side surface 513 of the base layer 51, or the base layer 51 is convex from the side surface 521 of the adhesive layer 52.

Compared with the prior art, the embodiment of the utility model, it is that shutoff piece 50 directly forms on first active material layer 12 among the prior art, does not have the design of the side indent of shutoff piece 50, is equivalent to the utility model discloses a basic unit 51 directly forms on first active material layer 12, leads to the circumferential N/P ratio of basic unit 51 to diminish.

The embodiment of the utility model provides an in, through setting up viscose layer 52, the orthographic projection's of viscose layer 52 on first mass flow body 11 area is less than basic unit 51 orthographic projection's on first mass flow body 11 area for viscose layer 52 is compared in basic unit 51's side indent. When lithium ions on the positive electrode sheet 20 are desorbed in a diffusion manner and move to the negative electrode sheet 10 through the micropores of the separator 30, part of the lithium ions can be embedded into the first active material layer 12 corresponding to the side surface of the base layer 51 and the side surface of the adhesive layer 52, that is, part of the lithium ions can be embedded into the first active material layer 12 from the position where the base layer 51 is recessed through the adhesive layer 52, specifically, part of the lithium ions can be additionally embedded into the first active material layer 12 at the inner side of the orthographic projection of the base layer 51 and at the outer side of the orthographic projection of the adhesive layer 52, so that the N/P ratio of the periphery of the blocking piece 50 can be increased, the risk of lithium precipitation at the periphery of the blocking piece 50 is reduced, and the safety of the battery is improved.

In an embodiment, referring to fig. 2 and fig. 3, a distance between an edge of an orthographic projection of the adhesive layer 52 on the first current collector 11 and an edge corresponding to an orthographic projection of the groove 13 on the first current collector 11 is W1. In other words, the distance between the sidewall 132 of the groove 13 and the side 521 of the adhesive layer 52 is W1. Satisfies the following conditions: w1 is more than or equal to 1mm and less than or equal to 5mm. On the one hand, the distance W1 cannot be too small, for example, less than 1mm, so that the adhesive layer 52 is difficult to be stably bonded to the first active material layer 12, which may cause a problem of unstable connection; on the other hand, if the distance W1 is not too large, for example, greater than 5mm, the adhesive layer 52 occupies too much of the first active material layer 12, which results in a reduction in the area of the negative electrode sheet 10 participating in the electrochemical reaction, and thus reduces the battery performance. The distance W1 is between 1mm and 5mm, so that the adhesive layer 52 and the base layer 51 can be stably connected and fixed to the first active material layer 12, the area of the first active material layer 12 is occupied relatively less, and the performance of the battery is influenced less. Alternatively, the distance may be 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, etc.

In an embodiment, referring to fig. 2 to fig. 5, an orthographic projection of the second surface 512 on the first current collector 11 completely covers an orthographic projection of the first surface 511 on the first current collector 11, that is, an area of the first surface 511 is smaller than or equal to an area of the second surface 512, and in the orthographic projection of the first current collector 11, an edge of the first surface 511 does not exceed an edge corresponding to the second surface 512, so that the orthographic projection of the base layer 51 on the first current collector 11 is an orthographic projection of the second surface 512 on the first current collector 11. The adhesive layer 52 is entirely located on the first surface 511, and at least one side of an orthographic projection of the adhesive layer 52 on the first current collector 11 has a spacing distance from a side corresponding to an orthographic projection of the second surface 512 on the first current collector 11.

In order to increase the N/P ratio, it is necessary to utilize the first active material layer 12 on the inner side of the orthographic projection of the base layer 51 and on the outer side of the orthographic projection of the adhesive layer 52 as much as possible to participate in the electrochemical reaction when the blocking member 50 blocks the lithium ions from entering the groove 13 in the case that the lithium ions enter the negative electrode sheet 10 through the micropores of the separator 30 while encountering the base layer 51 to block the lithium ions and then can move along the side 513 of the base layer 51 to the side 521 of the adhesive layer 52. The orthographic projection of the second surface 512 on the first current collector 11 completely covers the orthographic projection of the first surface 511 on the first current collector 11, the adhesive layer 52 is located on the first surface 511 of the base layer 51, so that lithium ions moving from the side surface 513 of the base layer 51 can move to the first active material layer 12 through the side surface 521 of the adhesive layer 52, and the phenomenon that the lithium ions are accumulated at the corner of the part of the adhesive layer 52 beyond the side surface 513 of the base layer 51 to cause lithium deposition is avoided, wherein the lithium ions are prevented from exceeding the side surface 513 of the base layer 51. At least one side of the orthographic projection of the adhesive layer 52 on the first current collector 11 has a spacing distance from the side of the second surface 512 corresponding to the orthographic projection on the first current collector 11, so that part of the first active material layer 12 is inevitably positioned on the inner side of the orthographic projection of the base layer 51 and on the outer side of the orthographic projection of the adhesive layer 52, and the N/P ratio can be improved.

In one embodiment, referring to fig. 2 to 5, the side 513 of the base layer 51 is at an angle of 15 ° to 90 ° with respect to the surface of the first active material layer 12 facing the membrane 30, and the area of the first surface 511 of the base layer 51 is smaller than or equal to the area of the second surface 512.

Alternatively, referring to fig. 2 and 3, the side 513 of the base layer 51 makes an angle of 90 ° with the surface of the first active material layer 12 facing the separator 30, and the area of the first surface 511 of the base layer 51 is equal to the area of the second surface 512. In other words, side 513 of base layer 51 is parallel to side 521 of adhesive layer 52, and both are perpendicular to the surface of first active material layer 12 facing separator 30.

Optionally, referring to fig. 4, at least a portion of the side surface 513 of the base layer 51 is a curved surface. As shown in fig. 4, the side surface 513 of the base layer 51 is an outward convex arc surface, and compared with the case that the lithium ions in fig. 3 need to turn (i.e., move to the side surface 513 of the base layer 51, then turn 90 ° to move to the first surface 511 of the base layer 51, and then turn 90 ° to enter the first active material layer 12 through the side surface 521 of the adhesive layer 52) to be embedded into the first active material layer 12 near the side surface 521 of the adhesive layer 52, the side surface 513 of the base layer 51 in the embodiment shown in fig. 4 is a curved surface, and the lithium ions can be embedded into the first active material layer 12 without turning greatly when moving, so that the moving speed of the lithium ions can be increased, and the efficiency can be improved.

Optionally, referring to fig. 2 and fig. 5, a side surface 513 of the base layer 51 is an inclined surface, and an included angle between the side surface 513 of the base layer 51 and a surface of the first active material layer 12 facing the separator 30 may be specifically 15 °,30 °, 45 °, 60 °, 75 °, 80 °, and the like, without limitation. The smaller the included angle, the larger the spacing distance between the side 521 of the adhesive layer 52 and the edge of the second surface 512 of the base layer 51, and the smaller the included angle is, the better the N/P ratio can be set.

In an embodiment, with reference to fig. 3 to 6, the following embodiment that the side 531 of the hot melt adhesive layer 53 is flush with the edge of the second surface 512 is taken as an example, and the edge of the second surface 512 in fig. 6 is indicated by using the reference numeral of the side 531 of the hot melt adhesive layer 53, so as to avoid confusion, which is defined herein and will not be described again. At least one side of the orthographic projection of the adhesive layer 52 on the first current collector 11 is overlapped with the side of the orthographic projection of the second surface 512 on the first current collector 11, and the remaining side of the orthographic projection of the adhesive layer 52 on the first current collector 11 has a spacing distance from the side of the orthographic projection of the second surface 512 on the first current collector 11. In other words, at least one side 521 of the adhesive layer 52 is flush with the second surface 512 of the base layer 51, and the remaining sides 521 of the adhesive layer 52 are spaced from the corresponding edge of the second surface 512 of the base layer 51. Fig. 6 shows an embodiment in which one side 521 of the adhesive layer 52 is flush with one edge of the second surface 512 of the base layer 51, and the remaining three sides 521 of the adhesive layer 52 are spaced apart from the remaining three edges of the second surface 512 of the base layer 51. At positions where the remaining three sides 521 of the adhesive layer 52 have a distance from the remaining three edges of the second surface 512 of the base layer 51, in conjunction with fig. 2, lithium ions can additionally enter into a portion of the first active material layer 12, increasing the N/P ratio. Specifically, when the adhesive layer 52 is disposed at the edge of the negative electrode sheet 10, the side 521 of the adhesive layer may be flush with the edge of the second surface 512 of the base layer 51, so that the negative electrode tab 40 protrudes from the negative electrode sheet 10 at a position corresponding to the flush position.

In other embodiments, the adhesive layer 52 may also have two sides 521 and three sides 521 flush with the edge of the second surface 512 of the base layer 51, and the remaining sides 521 are spaced from the edge of the second surface 512 of the base layer 51, which is not limited. In short, if the side 521 of the partial adhesive layer 52 is spaced apart from the edge of the second surface 512 of the base layer 51, the N/P ratio of the first active material layer 12 at the corresponding position can be increased.

Alternatively, as shown in fig. 6, one side 521 of the adhesive layer 52 is flush with the edge of the second surface 512 of the base layer 51, and the remaining sides 521 of the adhesive layer 52 are spaced from the corresponding edge of the second surface 512 of the base layer 51 by the same distance. The spacing distances are equal, so that the effects of improving the N/P ratio are basically the same, and the performances of the battery at all positions are more uniform and consistent.

Optionally, referring to fig. 2 and fig. 6, a distance between at least one side of an orthogonal projection of the adhesive layer 52 on the first current collector 11 and a side corresponding to an orthogonal projection of the second surface 512 on the first current collector 11 is W2. In other words, the distance between the side 521 of the adhesive layer 52 and the edge of the second surface 512 of the base layer 51 is W2. Satisfies the following conditions: w2 is more than or equal to 2mm and less than or equal to 8mm. When W2 is too small, the edge size difference is too small, the improvement of the N/P ratio is not obvious, and the risk of lithium precipitation still exists; when W2 is too large, the difference in edge size is too large, and since the edge portion has no or low tackiness during winding, it may be warped or bent during winding, resulting in poor flatness of the battery. When W2 is larger than or equal to 2mm and smaller than or equal to W2 and smaller than or equal to 8mm, the N/P ratio can be effectively improved, meanwhile, the warping or bending in the winding process can be avoided, and the flatness of the battery is improved. W2 may be 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, etc., without limitation.

In combination with the foregoing description, in the case that the side surfaces 521 of the adhesive layer 52 have a spacing distance from the edges of the second surface 512 of the base layer 51, the spacing distance of each corresponding edge may be equal or unequal, and is not limited.

In one embodiment, referring to fig. 2 and 3, the blocking member 50 further includes a hot melt adhesive layer 53, the hot melt adhesive layer 53 is disposed on a side of the base layer 51 opposite to the adhesive layer 52, i.e., on the second surface 512 of the base layer 51, and the hot melt adhesive layer 53 is used for bonding with the membrane 30 and blocking the micropores of the membrane 30 after being melted.

The negative electrode plate 10, the positive electrode plate 20 and the diaphragm 30 are hot-pressed after being wound into a winding core, so that the pole plate and the diaphragm 30 are attached more tightly, the hot-melt adhesive layer 53 is melted and blocks micropores of the diaphragm 30 facing to one side of the negative electrode plate 10 by the hot-pressing, lithium ions in the first area 23 of the positive electrode plate 20 are prevented from penetrating through the second area 31 of the diaphragm 30, and the problem that lithium ions are separated at the negative electrode tab 40 in the groove 13 is solved. Optionally, the hot melt adhesive layer 53 fills the second surface 512, that is, the side 531 of the hot melt adhesive layer 53 is flush with the edge of the second surface 512, as shown in fig. 3, the side 531 of the hot melt adhesive layer 53 is flush with the side 513 of the base layer 51, so that lithium ions cannot pass through the second region 31 of the diaphragm 30 corresponding to the second surface 512 of the base layer 51, and lithium ions are prevented from being accumulated at the corner between the second surface 512 and the side 531 of the hot melt adhesive layer 53.

In one embodiment, referring to fig. 7, a receiving groove 24 is formed on a side of the positive plate 20 facing the diaphragm 30, and the receiving groove 24 is opposite to the blocking piece 50.

When the negative electrode sheet 10, the positive electrode sheet 20, and the separator 30 are wound and hot-pressed, the position corresponding to the sealing member 50 protrudes from the surface of the negative electrode sheet 10 due to the presence of the sealing member 50, resulting in poor flatness of the negative electrode sheet 10. Through seting up storage tank 24 at positive plate 20, during the diaphragm 30 that shutoff piece 50 and correspondence can stretch into storage tank 24 when hot pressing, improved the not good problem of roughness, reduced the influence that sets up the thickness of shutoff piece 50 to electric core.

During specific setting, the accommodating groove 24 is formed in the second active material layer 22 on the side of the second current collector 21 facing the diaphragm 30, the opening of the accommodating groove 24 faces the diaphragm 30, the width of the accommodating groove 24 may be slightly larger than the width of the plugging piece 50, so that the plugging piece 50 and the corresponding diaphragm 30 can more conveniently extend into the accommodating groove 24, the requirement on processing accuracy can be reduced, and the accommodating groove 24 and the plugging piece 50 slightly deviate from each other, so that the plugging piece 50 and the corresponding diaphragm 30 can also extend into the accommodating groove 24.

Since the plugging member 50 plugs the lithium ions in the first region 23 of the second active material layer 22, when the accommodating groove 24 is formed, at least a portion of the accommodating groove 24 is located in the first region 23, so that the active material in the first region 23 is reduced, and the phenomenon of lithium deposition caused by the lithium ions moving to the negative electrode sheet 10 around the first region 23 is further reduced.

Optionally, referring to fig. 7, the depth of the accommodating groove 24 is h1, and the thickness of the blocking piece 50 is h2, which satisfy: h1 is more than or equal to h2. Satisfy this dimensional requirement, can make blocking piece 50 all stretch into storage tank 24 to make the thickness of electric core not receive blocking piece 50's influence completely, promote the roughness of electric core.

The embodiment of the utility model provides a still provide a battery, electric core including aforementioned arbitrary embodiment.

In the description of the embodiments of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and other indexes are the orientation or positional relationship described based on the drawings, and are only for convenience of description and simplification of the description, but not for indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

Claims (10)

1. A battery cell, comprising:

the negative plate comprises a first current collector and a first active material layer formed on the first current collector, wherein the first active material layer is provided with a groove, the groove penetrates through the first active material layer and extends to the first current collector, a negative lug is accommodated in the groove, and the negative lug is connected with the first current collector;

the sealing piece comprises a base layer and an adhesive layer, wherein the base layer comprises a first surface, the first surface faces the first current collector, one surface of the adhesive layer is bonded with the first surface, and the other surface of the adhesive layer is bonded with the first active material layer, so that the sealing piece completely covers the groove, and the orthographic projection area of the adhesive layer on the first current collector is smaller than that of the base layer on the first current collector;

the diaphragm is stacked on the negative plate and the plugging piece; and

and the positive plate is stacked on one side of the diaphragm, which is back to the negative plate.

2. The battery cell of claim 1, wherein a distance between an edge of an orthographic projection of the adhesive layer on the first current collector and an edge of the groove corresponding to the orthographic projection of the groove on the first current collector is W1, and satisfies: w1 is more than or equal to 1mm and less than or equal to 5mm.

3. The electrical core of claim 1, wherein the base layer further includes a second surface opposite to the first surface, an orthographic projection of the second surface on the first current collector completely covers an orthographic projection of the first surface on the first current collector, the adhesive layer is entirely located on the first surface, and at least one edge of the orthographic projection of the adhesive layer on the first current collector has a distance from an edge of the orthographic projection of the second surface on the first current collector.

4. The cell of claim 3, wherein at least one side of an orthographic projection of the adhesive layer on the first current collector overlaps with a side of the second surface corresponding to the orthographic projection of the second surface on the first current collector, and a distance is provided between the remaining side of the orthographic projection of the adhesive layer on the first current collector and the side of the second surface corresponding to the orthographic projection of the second surface on the first current collector.

5. The electric core of claim 3, wherein a distance between at least one side of an orthographic projection of the adhesive layer on the first current collector and a side corresponding to an orthographic projection of the second surface on the first current collector is W2, which satisfies: w2 is more than or equal to 2mm and less than or equal to 8mm.

6. The electrical core of claim 3, wherein the side of the base layer is at an angle of 15 ° to 90 ° to the surface of the first active material layer facing the separator.

7. The battery cell of claim 1, wherein the blocking element further comprises a hot melt adhesive layer, the hot melt adhesive layer is disposed on a side of the base layer opposite to the adhesive layer, and the hot melt adhesive layer is used for bonding with the separator and blocking the micropores of the separator after melting.

8. The battery cell of claim 1, wherein a containing groove is formed in one side of the positive plate facing the diaphragm, and the containing groove is opposite to the blocking piece.

9. The electric core of claim 8, wherein the depth of the accommodating groove is h1, the thickness of the blocking piece is h2, and the following requirements are satisfied: h1 is more than or equal to h2.

10. A battery comprising the cell of any of claims 1 to 9.

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