CN115939672A

CN115939672A - Diaphragm, preparation method, electrode assembly, battery monomer, battery and electricity utilization device

Info

Publication number: CN115939672A
Application number: CN202310249650.9A
Authority: CN
Inventors: 席飞; 淡江雷; 唐代春; 喻鸿钢
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Priority date: 2023-03-15
Filing date: 2023-03-15
Publication date: 2023-04-07

Abstract

The application relates to a diaphragm, a preparation method, an electrode assembly, a battery monomer, a battery and an electric device, wherein the diaphragm comprises: a substrate; the glue film sets up on at least one side surface of substrate along the thickness direction of substrate, and the glue film includes a plurality of rubber coating districts, and the interval sets up between every two adjacent rubber coating districts. The area of the substrate without glue is the white area, and the sum of the areas of all glue coating areas is smaller than the area of the white area. This application sets up a plurality of rubber coating districts of mutual interval on the substrate of diaphragm, and the rubber coating district can realize the stable bonding between diaphragm and the positive and negative pole piece, and the whole weight of diaphragm can be alleviateed in the not rubber coated region, from this, on the basis of guaranteeing that diaphragm and positive and negative pole piece firmly bond, alleviates the weight of diaphragm to the cost of diaphragm has been reduced.

Description

Diaphragm, preparation method, electrode assembly, battery monomer, battery and electricity utilization device

Technical Field

The application relates to the technical field of batteries, in particular to a diaphragm, a preparation method of the diaphragm, an electrode assembly, a battery monomer, a battery and an electricity utilization device.

Background

The lithium ion battery has the advantages of high energy density, high voltage platform, long cycle life, environmental protection and the like, and is widely applied to various fields. In the process of rapid development of lithium ion batteries, the cost and the structural portability become the restricting factors of lithium battery development.

In the battery structure, the diaphragm is positioned between the positive plate and the negative plate and is mainly used for separating the positive plate and the negative plate and preventing the two plates from being short-circuited due to contact. On the basis, the diaphragm has a bonding effect on the positive pole piece and the negative pole piece, so that the positive pole piece and the negative pole piece are kept relatively stable in the working process of the battery.

At present, a gluing diaphragm is arranged between a positive plate and a negative plate so as to bond and fix the positive plate and the negative plate, but the gluing diaphragm is high in cost and heavy in weight.

Disclosure of Invention

In view of the above, it is necessary to provide a separator, a manufacturing method thereof, an electrode assembly, a battery cell, a battery, and an electric device, in order to solve the problems of high cost and heavy weight of the conventional separator.

In a first aspect, the present application provides a separator for being disposed between a positive electrode sheet and a negative electrode sheet, the separator comprising:

a substrate;

the glue layer is arranged on at least one side surface of the base material along the thickness direction of the base material and comprises a plurality of glue coating areas, and every two adjacent glue coating areas are arranged at intervals;

the area of the substrate without glue is the white area, and the sum of the areas of all glue coating areas is smaller than the area of the white area.

Through setting up a plurality of rubber coating districts of mutual interval on the substrate, realize the stable bonding between diaphragm and positive plate or the negative pole piece through the rubber coating district to reduce the rubber coating volume on the substrate, can reduce the manufacturing cost of diaphragm. In addition, the whole weight of the diaphragm can be reduced in other areas except the gluing area on the base material, and when the diaphragm is combined with the positive plate and the negative plate together to form the single battery, the whole weight of the single battery can be reduced.

In addition, the sum of the areas of all the gluing areas is set to be smaller than the area of the white area, so that the gluing amount can be reduced as much as possible, the cost of the diaphragm is reduced, and the weight of the diaphragm is lightened.

In some embodiments, at least a portion of the total glue area is uniformly distributed over the surface on which it is located. At least part of the glue coating area is uniformly and alternately arranged on the substrate, and when the diaphragm is arranged between the positive plate and the negative plate, the uniformly arranged glue coating area can enable the adhesive force between the positive plate and the diaphragm and between the negative plate and the diaphragm to be more uniformly distributed, so that the adhesive force between the positive plate, the diaphragm and the negative plate is more stable.

In some embodiments, each rubberized region has a distribution density, on its surface, ranging from 0.05 to 0.55. Therefore, on the basis of ensuring stable bonding among the positive plate, the diaphragm and the negative plate, the glue coating amount used can be reduced to the maximum extent, and the cost and the weight of the diaphragm are reduced.

In some embodiments, each rubberized region has a thickness, in the thickness direction of the substrate, in the range 0.5 μm to 6 μm. Therefore, on the basis of ensuring the stable bonding of the diaphragm to the positive plate or the negative plate, the glue coating amount is reduced as much as possible, so that the cost of the diaphragm is reduced, and the weight of the diaphragm is lightened.

In some embodiments, each rubberized region has a thickness, in the thickness direction of the substrate, in the range 1 μm to 3 μm. Therefore, the coating amount can be further reduced on the basis of ensuring the stable bonding of the separator to the positive electrode sheet or the negative electrode sheet, so that the cost of the separator is further reduced, and the weight of the separator is reduced.

In some embodiments, each glue section is one or more of circular, elliptical, polygonal in shape.

The gluing areas are set to be different shapes, so that the adhesive force of the diaphragm between the positive plate and the negative plate has different distribution conditions, and the adhesive effect of the diaphragm on the positive plate and the negative plate is adjusted according to actual requirements.

In some embodiments, the ratio of the sum of the areas of all rubberized regions to the area of the white space is 0.05-0.8. Therefore, the production cost of the separator can be reduced as much as possible and the weight of the separator can be reduced while ensuring stable adhesion of the separator to the positive electrode sheet and the negative electrode sheet.

In some embodiments, each glue section is shaped as a circle of equal diameter and arranged in an array along a first direction and a second direction on the surface on which it is located;

wherein the first direction intersects the second direction.

Through the structure, the adhesive force between the diaphragm and the positive plate and between the diaphragm and the negative plate can be distributed more uniformly, and the adhesive stability between the positive plate, the diaphragm and the negative plate is improved.

In some embodiments, the glue layer further comprises a glue strip area, wherein the glue strip area is positioned on at least one side of the glue coating area along the width direction of the base material and extends along the length direction of the base material. Through setting up the adhesive tape district, can strengthen the bonding firmness between diaphragm and positive plate and the negative pole piece, effectively reduce electrolyte and erode and the probability of the inside short circuit of battery monomer that leads to.

In some embodiments, the width of the adhesive tape region in the width direction of the substrate ranges from 1mm to 6mm. Therefore, on the basis of ensuring that the edges of the positive plate and the negative plate are firmly bonded by the diaphragm, the glue coating amount of the glue strip area can be reduced, so that the production cost of the diaphragm is reduced, and the whole weight of the diaphragm is reduced.

In some embodiments, the width of the adhesive strip region in the width direction of the substrate ranges from 2mm to 4mm. From this, can guarantee that the bonding at the edge between diaphragm and positive plate and the negative pole piece is more firm to can further reduce the rubber coating volume in adhesive tape district, reduce the manufacturing cost of diaphragm, alleviate the whole weight of diaphragm.

In some embodiments, the thickness of the stripe region in the thickness direction of the substrate is in the range of 0.5 μm to 6 μm. Therefore, on the basis of ensuring the stable bonding of the adhesive tape area to the edges of the positive plate and the negative plate, the adhesive coating amount of the adhesive tape area is reduced as much as possible, the cost of the diaphragm is reduced, and the weight of the diaphragm is reduced.

In some embodiments, the thickness of the stripe region in the thickness direction of the substrate ranges from 1 μm to 3 μm. Therefore, the adhesive coating amount of the adhesive tape area can be further reduced on the basis of ensuring the stable adhesion of the diaphragm to the edges of the positive plate and the negative plate, so that the cost of the diaphragm is further reduced, and the weight of the diaphragm is reduced.

In a second aspect, the present application provides an electrode assembly, including positive plate, negative plate and set up the diaphragm between positive plate and negative plate, the diaphragm is as above, and the surface that is equipped with the glue film on the substrate sets up with the laminating of positive plate and/or negative plate.

In a third aspect, the present application provides a battery cell comprising an electrode assembly as described above.

In a fourth aspect, the present application provides a battery comprising a battery cell as described above.

In a fifth aspect, the present application provides an electric device comprising the battery as described above.

In a sixth aspect, the present application provides a method for preparing a separator as described above, the method comprising the steps of:

and gluing at least one side surface of the base material along the thickness direction of the base material to form a plurality of gluing areas which are arranged at intervals.

In some embodiments, the method of making further comprises the steps of:

the adhesive tape is attached to at least one side of the gluing area along the width direction of the base material and extends along the length direction of the base material to form an adhesive tape area.

According to the diaphragm, the preparation method, the electrode assembly, the battery monomer, the battery and the power device, the plurality of mutually-spaced glue coating areas are arranged on the base material of the diaphragm, the glue coating areas can realize stable bonding between the diaphragm and the positive and negative pole pieces, and the whole weight of the diaphragm can be reduced in the non-glue coated areas, so that the weight of the diaphragm is reduced on the basis of ensuring firm bonding between the diaphragm and the positive and negative pole pieces, and the cost of the diaphragm is reduced.

Drawings

FIG. 1 is a schematic diagram of a diaphragm in accordance with one or more embodiments;

FIG. 2 is a side view of a septum in accordance with one or more embodiments;

FIG. 3 isbase:Sub>A sectional view taken along line A-A of FIG. 1;

fig. 4 is a schematic view of the structure of an electrode assembly according to one or more embodiments.

Description of the reference numerals:

100. an electrode assembly;

10. a diaphragm; 20. a positive plate; 30. a negative plate;

11. a substrate; 12. a glue layer;

111. a white region is left; 121. a glue spreading area; 122. a glue strip area;

a. the thickness direction of the base material; b. the width direction (second direction) of the base material; c. the longitudinal direction of the substrate (first direction).

Detailed Description

In order to make the aforementioned objects, features and advantages of the present application more comprehensible, embodiments accompanying the present application are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. This application is capable of embodiments in many different forms than those described herein and that modifications may be made by one skilled in the art without departing from the spirit and scope of the application and it is therefore not intended to be limited to the specific embodiments disclosed below.

In the description of the present application, it is to be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the present application and for simplicity in description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the present application.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or to implicitly indicate the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless explicitly specified otherwise.

In this application, unless expressly stated or limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can include, for example, fixed connections, removable connections, or integral parts; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

In this application, unless expressly stated or limited otherwise, a first feature is "on" or "under" a second feature such that the first and second features are in direct contact, or the first and second features are in indirect contact via an intermediary. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

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 and electric automobiles and other fields. With the continuous expansion of the application field of the power battery, the market demand is also continuously expanding.

In the structure of the battery, one or more battery cells are generally included, i.e., the battery cell is the smallest unit constituting the battery. The plurality of battery monomers can be connected in series or in parallel or in series-parallel, and the series-parallel refers to the series connection and the parallel connection of the plurality of battery monomers.

Further, in the structure of the battery cell, an electrode assembly is further included. Wherein the electrode assembly is a part in which electrochemical reactions occur in the battery cell. The electrode assembly is mainly formed by winding or stacking a positive electrode sheet and a negative electrode sheet, and a separator is generally disposed between the positive electrode sheet and the negative electrode sheet. The portions of the positive and negative electrode sheets having the active material constitute the main body portion of the electrode assembly, and the portions of the positive and negative electrode sheets having no active material each form the tab portion.

When the diaphragm is arranged between the positive plate and the negative plate, the diaphragm is mainly used for separating active substances on the positive plate and the negative plate and preventing the two electrodes from short circuit due to contact. Meanwhile, the diaphragm is positioned between the positive plate and the negative plate and is respectively bonded with the positive plate and the negative plate, so that the positive plate and the negative plate can be relatively stable and do not move relatively. Therefore, when electrochemical reaction occurs, a stable ion moving channel is formed between the positive plate and the negative plate by the electrolyte, and stable charging and discharging of the battery are realized.

At present, the diaphragm arranged between the positive plate and the negative plate is generally a gluing diaphragm, wherein the gluing diaphragm is evenly glued on the two side surfaces along the thickness direction of the gluing diaphragm. The gluing diaphragm is used for bonding the positive plate and the negative plate, so that the positive plate, the negative plate and the diaphragm can be bonded more firmly. However, the cost of a rubberized separator is often high, and the use of a rubberized separator increases the overall cost of the battery. In addition, the rubberized separator is heavy in its own weight due to the full-scale rubberizing, which ultimately affects the overall weight of the battery.

Based on the consideration, in order to solve the problems that the cost and the weight of the existing diaphragm are high and heavy, and the overall cost and the weight of the battery are affected, one or more embodiments of the application provide a diaphragm, a plurality of mutually-spaced glue coating areas are arranged on a base material of the diaphragm, the glue coating areas can realize stable bonding between the diaphragm and positive and negative pole pieces, and the non-glue coated areas can reduce the overall weight of the diaphragm, so that the weight of the diaphragm is reduced on the basis of ensuring firm bonding between the diaphragm and the positive and negative pole pieces, and the cost of the diaphragm is reduced.

The battery cell disclosed in the embodiment of the application can be used in electric devices such as vehicles, ships or aircrafts, but not limited thereto. The power supply system with the battery cell, the battery and the like can be used, so that the cost and the weight of the whole battery can be reduced.

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 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.

Referring to fig. 1 and 2, in one or more embodiments, a separator 10 is provided for being disposed between a positive electrode tab and a negative electrode tab. The diaphragm 10 includes a substrate 11 and an adhesive layer 12, the adhesive layer 12 is disposed on at least one side surface of the substrate 11 along a thickness direction a of the substrate 11, the adhesive layer 12 includes a plurality of adhesive areas 121, and every two adjacent adhesive areas 121 are disposed at intervals.

It should be noted that the substrate 11 is a main body part of the separator 10, which is used to provide a support base for the adhesive layer 12, and when the separator 10 is disposed between the positive plate and the negative plate, the substrate 11 can separate the positive plate and the negative plate. Alternatively, the substrate 11 may be, but is not limited to, a polypropylene or polyethylene microporous membrane, and the glue coated region 121 on the substrate 11 may be, but is not limited to, coated with one or more of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene mixture, polyvinylidene fluoride-chlorotrifluoroethylene mixture, polytetrafluoroethylene, polymethyl methacrylate, polyacrylonitrile, and polyethylene oxide.

Two surfaces of the substrate 11, which are oppositely arranged in the thickness direction a of the substrate, are respectively used for being laminated and attached to the positive plate or the negative plate, that is, when the diaphragm 10 is arranged between the positive plate and the negative plate, the positive plate, the diaphragm 10 and the negative plate are laminated in the thickness direction a of the substrate 11.

Further, the adhesive layer 12 may be disposed on only one surface of the substrate 11 in the thickness direction a, and the substrate 11 may be attached to the positive electrode tab or the negative electrode tab through the one surface on which the adhesive layer 12 is disposed. Of course, the adhesive layer 12 may be disposed on both side surfaces of the base material 11 in the thickness direction a, and the both side surfaces on which the adhesive layer 12 is disposed may be respectively attached to the positive electrode sheet and the negative electrode sheet.

The adhesive layer 12 includes a plurality of adhesive areas 121 disposed at intervals, and the adhesive areas 121 have adhesion property and can be used for adhesion between the positive electrode plate and the negative electrode plate. On the other hand, the other regions on the substrate 11 except the glue coating region 121 may provide a space for storing the electrolyte, so that the electrolyte has a better wetting effect on the active material layer on the positive electrode plate or the negative electrode plate.

It should be noted that there are some solutions to reduce the cost and weight of the separator by reducing the thickness of the glue, however, in this solution, because the thickness of the glue is thinner, when the separator is disposed between the positive plate and the negative plate, the adhesive force of the separator to the positive plate and the negative plate is smaller, and the separator is easily separated from the positive plate and the negative plate under the scouring action of the electrolyte, thereby causing the internal short circuit.

And set up a plurality of rubber coating districts of mutual interval on the substrate in this application, when the diaphragm set up between positive plate and negative pole piece, the rubber coating district can realize with the positive plate or with the bonding between the negative pole piece. In addition, the gluing area on the base material is reduced because the gluing area adopts the mode of interval coating. On the premise, the gluing thickness of each gluing area does not need to be reduced, even the gluing thickness of each gluing area can be correspondingly increased, and the total weight and the total cost of the diaphragm are comprehensively regulated and controlled by controlling the total gluing amount of each gluing area so as to be kept in a proper range.

Based on this, each gluing area is firmly bonded with the positive plate or the negative plate. In addition, even if one or more glue coating areas are separated from the pole piece due to external factors, other glue coating areas can still ensure stable bonding between the diaphragm and the pole piece.

Therefore, by arranging the glue coating areas 121 at intervals on the substrate 11, the stable bonding between the diaphragm 10 and the positive plate or the negative plate is realized through the glue coating areas 121, the glue coating amount on the substrate 11 is reduced, and the production cost of the diaphragm 10 can be reduced. In addition, the weight of the separator 10 can be reduced in the other regions of the substrate 11 except for the glue-coated region 121, and when the separator 10 is combined with the positive electrode sheet and the negative electrode sheet to form a battery cell, the weight of the battery cell can be reduced.

In some embodiments, at least a portion of the total glue segment 121 is uniformly distributed over the surface on which it is disposed. Specifically, at least part of the glue coating area 121 is uniformly and intermittently arranged on the substrate 11, and when the diaphragm 10 is arranged between the positive plate and the negative plate, the uniformly arranged glue coating area 121 can enable the adhesive force between the positive plate and the negative plate and the diaphragm 10 to be more uniformly distributed, so that the adhesive force between the positive plate, the diaphragm 10 and the negative plate is more stable.

Optionally, all the glue-coated regions 121 are uniformly and alternately arranged on the surface where the glue-coated regions are located, and each glue-coated region 121 is a bonding point between the separator 10 and the positive electrode sheet or the negative electrode sheet. Therefore, the bonding points are uniformly distributed, so that the bonding force among the positive plate, the diaphragm 10 and the negative plate can be uniformly distributed, and the bonding among the positive plate, the diaphragm 10 and the negative plate is more stable.

Furthermore, the bonding points are evenly distributed, that is, the distance between two adjacent bonding points is equal. When electrolyte erodes positive plate, diaphragm 10 and negative pole piece, the scouring force that the diaphragm 10 between two adjacent bonding points received is equal basically to can realize the homodisperse to total scouring force, reduce the probability that rubber coating district 121 breaks away from with positive plate or negative pole piece under the scouring action of electrolyte, make the bonding between diaphragm 10 and positive plate and the negative pole piece more firm.

In some embodiments, each glue section 121 has a distribution density of 0.05 to 0.55 on its surface.

In particular, the distribution density refers to the degree of density of the glue areas 121 distributed on the surface thereof per unit area, i.e. the smaller the distribution density, the smaller the number of glue areas 121 on the surface thereof, the more discrete the distribution. The greater the distribution density, the greater the number of glue sections 121 on the surface on which they are located, and the denser the distribution.

The distribution density of each glue-coated region 121 on the surface thereof will directly affect the bonding effect of the separator 10 on the positive and negative electrode sheets, as well as the production cost and weight of the separator 10.

If the distribution density of each glue section 121 is too small, the spacing distance between the adjacent glue sections 121 is larger. At this time, the total area of the glue coating area 121 on the substrate 11 is small, and although the glue coating amount required is small, the cost and the weight of the separator 10 can be reduced, the adhesion force between the separator 10 and the positive plate and the negative plate is also small, and the adhesion among the positive plate, the separator 10 and the negative plate may be not firm enough, so that the relative offset between the positive plate and the negative plate occurs, and the performance of the battery cell is affected.

If the distribution density of the glue sections 121 is too high, the spacing distance between the adjacent glue sections 121 is small. In this case, the sum of the areas of the glue application regions 121 on the substrate 11 is large, and a larger amount of glue application needs to be used, which results in a higher cost and a heavier weight of the separator 10.

On the basis, how to set the distribution density of the glue coating area 121 on the substrate 11 to find a balance between the bonding effect of the diaphragm 10 and the cost and weight is very important, so that the glue coating amount can be reduced to the greatest extent and the cost and weight of the diaphragm 10 can be reduced on the basis of ensuring stable bonding between the diaphragm 10 and the positive plate and the negative plate.

Through specific experimental demonstration, the distribution density of each glue coating area 121 on the surface where the glue coating area is located is set to be 0.05-0.55, so that the used glue coating amount can be reduced to the greatest extent on the basis of ensuring stable bonding among the positive plate, the diaphragm 10 and the negative plate, and the cost and the weight of the diaphragm 10 are reduced.

It should be noted that, in a specific embodiment, the distribution density of each glue application area 121 on the surface thereof may adopt different measurement methods according to the shape of each glue application area 121.

In some embodiments, each glue section 121 is one or more of circular, elliptical, polygonal in shape.

Specifically, each glue application area 121 may be shaped as a circle, an ellipse, a triangle, a quadrangle, a pentagon, or other irregular figure. Of course, the shape of each glue application area 121 can be selected from one of the above shapes, and can also be combined with a plurality of the above shapes.

When the shapes of the glue sections 121 are arranged in an irregular pattern or the glue sections 121 are unevenly distributed on the surface on which they are located, the distribution density of the glue sections 121 on the surface on which they are located may be measured using, for example, a Scanning Electron Microscope (SEM) or other tool.

Specifically, when measuring the distribution density of each glue section 121 on the surface on which it is located by SEM, the number of glue sections 121 per unit area on the surface on which the glue sections 121 are located is first scanned by SEM, and the area of each glue section 121 is obtained by SEM, thereby obtaining the total area of the glue sections 121 within that unit area. Then, the distribution density of the coated regions 121 can be obtained by the ratio of the total area of the coated regions 121 within the unit area to the unit area.

In order to improve the accuracy of measurement, a plurality of unit areas may be selected for scanning, and the number of the unit areas for specific scanning may be adjusted according to actual requirements, which is not described herein.

Further, the actual value of the unit area may also be selected according to actual requirements, for example, 1 cm x1 cm may be selected as the unit area, and 10 cm x10 cm may also be selected as the unit area, which is not described herein.

When the shape of each glue section 121 is set to be a regular pattern and each glue section 121 is uniformly and intermittently distributed on the surface where it is located, the distribution density can be obtained by a calculation method. Specifically, the glue sections 121 are arranged in an array along a first direction and a second direction on the surface thereof, wherein the first direction intersects the second direction. Firstly, the length of the connecting line of the geometric centers of two adjacent glue coating areas 121 in the first direction is measured and recorded as A ₁ Measuring the length of the connecting line of the geometric centers of two adjacent glue coating areas 121 in the second direction and recording the length as A ₂ . Through A ₁ And A ₂ Calculating to obtain the area S of a quadrangle formed by the enclosed circle center distances of the four adjacent rubber coating areas 121 ₁ Then, the area S of the four adjacent glue coating areas 121 falling into the quadrangle is calculated ₂ Finally obtaining S ₂ And S ₁ The ratio of (a) to (b) is the distribution density of each glue application area 121 on the surface on which it is located.

As a specific example, each glue segment 121 is shaped as a circle of equal diameter, and the glue segments 121 are arranged in an array along a first direction and a second direction on the surface on which they are located. Wherein the first direction intersects the second direction.

Specifically, the first direction is set to be perpendicular to the second direction, and the first direction is set to be the length direction c of the base material 11, and the second direction is set to be the width direction b of the base material 11. Thus, the glue coated areas 121 are arranged in a rectangular array on the surface on which they are located. When the diaphragm 10 is arranged between the positive plate and the negative plate, the distribution of the adhesive force between the diaphragm 10 and the positive plate and between the diaphragm 10 and the negative plate can be more uniform, and the adhesive stability between the positive plate, the diaphragm 10 and the negative plate can be improved.

Further, the shape of all the glue coating areas 121 is set to be circular with the same diameter, so that the adhesive force of each glue coating area 121 to the positive plate or the negative plate is equal, and the adhesive force applied to the positive plate or the negative plate is more uniform.

Further, the radius of each glue area 121 is r, and the distance between the centers of two adjacent glue areas 121 in the first direction and the second direction is A ₃ The distribution density of each glue segment 121 on the surface on which it is located is then pi r ² / A ₃ ² 。

Therefore, the number of the glue application areas 121 arranged on the surface of the diaphragm can be adjusted according to the size of each glue application area 121, so that the glue application amount on the base material 11 can be adjusted according to the actual use condition, the adhesive force of the diaphragm 10 is ensured, the production cost of the diaphragm 10 is reduced, and the weight of the diaphragm 10 is reduced.

It is understood that in some other embodiments, the distribution density of the glue spreading area 121 on the surface may also be calculated according to the specific shape of the glue spreading area, which is not described herein.

Referring to FIG. 3, in some embodiments, the thickness of each glue segment 121 is within a range h in the thickness direction a of the substrate 11 ₁ Is 0.5-6 μm.

Specifically, the thickness of the glue segment 121 refers to the height of the glue segment 121 protruding from the surface of the substrate 11 in the thickness direction a of the substrate 11. The greater the thickness of the glue application zone 121, the greater the amount of glue application that needs to be used. On the one hand, this leads to an increase in the cost of the separator 10, and on the other hand, this leads to an increase in the overall thickness of the separator 10, which increases the weight of the separator 10. Conversely, if the thickness of the glue-coated region 121 is smaller, the adhesion of the glue-coated region 121 is smaller, which may result in an insufficient adhesion of the separator 10 to the positive or negative electrode sheet.

Therefore, the thickness of each glue coating area 121 is set to be between 0.5 μm and 5 μm, and the glue coating amount is reduced as much as possible on the basis of ensuring the stable bonding of the separator 10 to the positive electrode sheet or the negative electrode sheet, thereby reducing the cost of the separator 10 and reducing the weight of the separator 10.

In some embodiments, the thickness range h of each glue coated section 121 in the thickness direction a of the substrate 11 ₁ Is 1 μm to 3 μm.

In particular, the thickness of each glue-coated area 121 is set between 1 μm and 3 μm, which is a preferred embodiment. That is, the thickness of the glue coating region 121 is set to be 1 μm to 3 μm, so that the amount of glue coating can be further reduced while ensuring stable adhesion of the separator 10 to the positive electrode sheet or the negative electrode sheet, thereby further reducing the cost of the separator 10 and reducing the weight of the separator 10.

Referring to fig. 1 and 3 together, in some embodiments, the non-glued area of the substrate 11 is the white space 111, and the sum of the areas of all glue-coated areas 121 is smaller than the area of the white space 111.

Specifically, the glue-coated sections 121 are spaced apart from each other, and the blank regions 111 are formed at the spaced positions. Therefore, the glue-coated region 121 and the blank region 111 may surround each other, and uniform distribution of the adhesive force between the separator 10 and the positive and negative electrode sheets is achieved by the glue-coated region 121.

Thus, the total area of all the glue-applied regions 121 is set to be smaller than the area of the margin region 111, so that the amount of applied glue can be reduced as much as possible, thereby reducing the cost of the separator 10 and the weight of the separator 10.

In some embodiments, the ratio of the sum of the areas of all glue coated areas 121 to the area of the blank area 111 is 0.05-0.8.

The smaller the ratio of the sum of the areas of all the coated portions 121 to the area of the margin portion 111, the smaller the ratio of the sum of the areas of all the coated portions 121 to the substrate 11, and the larger the ratio of the area of the margin portion 111 to the substrate 11. In this case, the smaller the coating amount on the substrate 11, the lower the production cost and the lighter the weight of the separator 10. However, the smaller the adhesion of the separator 10 to the positive and negative electrode sheets.

The larger the ratio of the sum of the areas of all the coated portions 121 to the area of the margin portion 111, the larger the ratio of the sum of the areas of all the coated portions 121 to the substrate 11, and the smaller the ratio of the area of the margin portion 111 to the substrate 11. In this case, the greater the adhesion of the separator 10 to the positive electrode sheet and the negative electrode sheet, that is, the greater the firmness of adhesion between the positive electrode sheet, the separator 10, and the negative electrode sheet. However, the greater the amount of glue applied to the substrate 11, the higher the production cost and the heavier the weight of the separator 10.

Based on this, setting the ratio of the total area of all the glue-coated regions 121 to the area of the blank regions 111 to 0.05 to 0.8 can reduce the production cost of the separator 10 as much as possible and reduce the weight of the separator 10 while ensuring stable adhesion of the separator 10 to the positive electrode sheet and the negative electrode sheet.

In some embodiments, the glue layer 12 further comprises a glue strip region 122, and the glue strip region 122 is located on at least one side of the glue coating region 121 along the width direction b of the base material 11 and extends along the length direction c of the base material 11.

Specifically, when the separator 10 is stacked with the positive electrode sheet and the negative electrode sheet, the width direction b of the substrate 11 is the width direction of the electrode sheets (including the positive electrode sheet and the negative electrode sheet), and the length direction c of the substrate 11 is the length direction of the electrode sheets.

When the positive electrode sheet, the separator 10, and the negative electrode sheet are laminated or wound to form an electrode assembly, the width direction b of the substrate 11 is the height direction of the electrode assembly, the length direction c of the substrate 11 is the width direction of the electrode assembly, and the thickness direction a of the substrate 11 is the thickness direction of the electrode assembly.

Further, after the electrode assembly is placed in the case to form the battery cell, the liquid injection port of the battery cell is close to one side of the electrode assembly in the width direction b of the base material 11 (i.e., the height direction of the electrode assembly). At this time, when the electrolyte is injected into the case through the injection port, the impact force of the electrolyte on the edges of the positive electrode sheet, the separator 10, and the negative electrode sheet in the width direction b of the base material 11 (i.e., the height direction of the electrode assembly) is larger, which easily causes the separator 10 at the edge of the electrode assembly 100 to be stuck between the positive electrode sheet and the negative electrode sheet, thereby causing a short circuit inside the battery cell.

Based on this, the adhesive tape section 122 is provided on at least one side of the adhesive coating section 121 in the width direction b of the base material 11, and the adhesive tape section 122 is provided extending in the length direction c of the base material 11. The adhesive tape area 122 can enable the positive plate, the diaphragm 10 and the negative plate to be bonded more firmly at the edge, and reduce the probability that the diaphragm 10 stays down due to the scouring of the electrolyte.

Wherein, the adhesive tape section 122 may be disposed at one side of the adhesive tape section 121 in the width direction b of the base material 11, and after the separator 10 forms an electrode assembly together with the positive and negative electrode sheets, the side having the adhesive tape section 122 is disposed at one end near the liquid injection port, so that the edge of the electrode assembly can be prevented from being washed away by the electrolyte.

Of course, the adhesive tape regions 122 may be disposed on both sides of the adhesive tape region 121 in the width direction b of the substrate 11, so that the adhesion firmness between the separator 10 and the positive and negative electrode sheets can be further improved.

From this, through setting up adhesive tape district 122, can strengthen the bonding firmness between diaphragm 10 and positive plate and the negative plate, effectively reduce electrolyte and erode and the probability of the inside short circuit of battery cell that leads to.

It is understood that the material used in the adhesive tape section 122 may be the same as the adhesive tape section 121, that is, the material of the adhesive tape attached to the adhesive tape section 122 may be, but is not limited to, one or more of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene mixture, polyvinylidene fluoride-chlorotrifluoroethylene mixture, polytetrafluoroethylene, polymethyl methacrylate, polyacrylonitrile, and polyethylene oxide.

In some embodiments, the width d of the bead zone 122 in the width direction b of the substrate 11 ₁ Is 1mm-6mm.

Specifically, the smaller the width of the strip section 122, the smaller the amount of glue applied to the strip section 122, the lower the production cost of the membrane 10 as a whole, and the lighter the overall weight of the membrane 10. However, this results in less adhesion between the separator 10 and the positive and negative electrode sheets at the edge positions, thereby increasing the probability of the separator 10 being washed away by the electrolyte and becoming stuck.

The larger the width of the tab area 122 is, the larger the adhesion of the tab area 122 to the positive electrode sheet and the negative electrode sheet is, and the stronger the adhesion among the positive electrode sheet, the separator 10 and the negative electrode sheet is. However, the amount of glue applied to the glue stripe region 122 may increase, resulting in an increase in the production cost of the separator 10 and an increase in the overall weight of the separator 10.

Based on this, the width of the adhesive tape area 122 is set to be 1mm-6mm, and on the basis of ensuring that the diaphragm 10 is firmly bonded with the edges of the positive plate and the negative plate, the adhesive coating amount of the adhesive tape area 122 can be reduced, so that the production cost of the diaphragm 10 is reduced, and the overall weight of the diaphragm 10 is reduced.

In some embodiments, the width d of the strip zone 122 in the width direction b of the substrate 11 ₁ Is 2mm-4mm.

Optionally, the width of the adhesive tape area 122 is set between 2mm and 4mm, so that the edge bonding between the diaphragm 10 and the positive plate and the negative plate can be ensured to be firmer, the adhesive coating amount of the adhesive tape area 122 can be further reduced, the production cost of the diaphragm 10 is reduced, and the overall weight of the diaphragm 10 is reduced.

As shown in FIG. 2, in some embodiments, the bead area 122 has a thickness range h in the thickness direction a of the substrate 11 ₂ Is 0.5-6 μm.

Specifically, the thickness of the bead region 122 is a height at which the bead region 122 protrudes from the surface of the base material 11 in the thickness direction a of the base material 11. The greater the thickness of the strip section 122, the greater the amount of glue applied in the strip section 122. On the one hand, this leads to an increase in the cost of the separator 10, and on the other hand, this leads to an increase in the overall thickness of the separator 10, which increases the weight of the separator 10.

If the thickness of the adhesive tape area 122 is smaller, the adhesive force of the adhesive tape area 122 to the positive electrode plate and the negative electrode plate is smaller, the probability that the diaphragm 10 falls under the scouring action of the electrolyte is increased, and therefore the risk that the battery cell is internally short-circuited is increased.

Therefore, the thickness of the adhesive tape area 122 is set to be between 0.5 μm and 6 μm, so that the adhesive coating amount of the adhesive tape area 122 is reduced as much as possible, the cost of the separator 10 is reduced, and the weight of the separator 10 is reduced on the basis of ensuring the stable adhesion of the adhesive tape area 122 to the edges of the positive electrode plate and the negative electrode plate.

In some embodiments, the bead zone 122 has a thickness range h in the thickness direction a of the substrate 11 ₂ Is 1 μm to 3 μm.

In particular, it is a preferred embodiment to set the thickness of the strip region 122 between 1 μm and 3 μm. That is, the thickness of the bead region 122 is set to be 1 μm to 3 μm, so that the amount of bead of the bead region 122 can be further reduced while ensuring stable adhesion of the separator 10 to the edges of the positive electrode sheet and the negative electrode sheet, thereby further reducing the cost of the separator 10 and reducing the weight of the separator 10.

Referring to fig. 4, the present application provides an electrode assembly 100 including a positive electrode tab 20, a negative electrode tab 30, and a separator 10 disposed between the positive electrode tab 20 and the negative electrode tab 30, based on the same concept as the above-described separator 10. The separator 10 is the separator 10 described above, and the surface of the substrate 11 on which the adhesive layer 12 is provided is attached to the positive electrode sheet 20 and/or the negative electrode sheet 30.

Based on the same concept as the electrode assembly 100 described above, the present application provides a battery cell including the electrode assembly 100 as described above.

Based on the same concept as the battery cell described above, the present application provides a battery including the battery cell as described above.

Based on the same concept as the above battery, the present application provides an electric device including the battery as described above.

Based on the same concept as the separator 10 described above, the present application provides a method of manufacturing a separator 10 for manufacturing the separator 10 as described above, wherein the method of manufacturing includes the steps of:

gluing at least one side surface of the base material 11 along the thickness direction a to form a plurality of gluing areas 121 arranged at intervals;

the adhesive tape is attached to at least one side of the adhesive coating area 121 along the width direction b of the base material 11, and the adhesive tape extends along the length direction c of the base material 11 to form an adhesive tape area 122.

According to one or more embodiments, firstly, glue is applied to the two side surfaces of the substrate 11 along the thickness direction a of the substrate 11 to form a plurality of glue application areas 121 which are spaced from each other and distributed uniformly, and then adhesive tapes are respectively attached to the two sides of the glue application areas 121 along the width direction b of the substrate 11, the adhesive tapes extending along the length direction c of the substrate 11, so as to form adhesive tape areas 122 on the substrate 11.

Further, the positive electrode sheet 20, the separator 10, and the negative electrode sheet 30 are sequentially stacked, so that the separator 10 functions as an isolation and an adhesion between the positive electrode sheet 20 and the negative electrode sheet 30. Therefore, the glue application area 121 and the glue strip area 122 are arranged, so that the use amount of glue applied to the base material 11 can be reduced, and the production cost of the diaphragm 10 is reduced.

In addition, the blank regions 111 between the adjacent glue coating regions 121 can reduce the overall weight of the separator 10, and the blank regions 111 can provide a space for storing the electrolyte, so that the electrolyte has a better wetting effect on the active material layer on the positive electrode sheet 20 or the negative electrode sheet 30.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several implementation modes of the present application, and the description thereof is specific and detailed, but not construed as limiting the scope of the claims. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A separator for being disposed between a positive electrode sheet and a negative electrode sheet, comprising:

a substrate;

the glue layer is arranged on at least one side surface of the base material along the thickness direction of the base material, the glue layer comprises a plurality of glue coating areas, and every two adjacent glue coating areas are arranged at intervals;

the area of the base material without glue is a white area, and the sum of the areas of all glue coating areas is smaller than the area of the white area.

2. A diaphragm according to claim 1, wherein at least some of all of said glue areas are evenly distributed over the surface on which they are located.

3. A diaphragm according to claim 2, wherein each of said rubberized regions has a distribution density of 0.05 to 0.55 over its surface.

4. Separator according to claim 1, wherein each of said rubberized regions has a thickness in the range 0.5 μm to 6 μm, in the thickness direction of said substrate.

5. Separator according to claim 4, wherein each of said rubberized regions has a thickness, in the thickness direction of said substrate, in the range from 1 μm to 3 μm.

6. A diaphragm according to claim 1, wherein each glue area is one or more of circular, elliptical, polygonal in shape.

7. A diaphragm according to claim 1, wherein the ratio of the sum of the areas of all of said glue-coated regions to the area of said whitening region is 0.05-0.8.

8. A diaphragm according to any one of claims 1 to 7, wherein each of said glue areas is shaped as a circle of equal diameter and arranged in an array in a first direction and a second direction on its surface;

wherein the first direction intersects the second direction.

9. The membrane of claim 1, wherein the glue layer further comprises a glue strip area, and the glue strip area is located on at least one side of the glue coating area along the width direction of the substrate and extends along the length direction of the substrate.

10. Separator according to claim 9, wherein the width of the strip area in the width direction of the substrate is in the range of 1mm to 6mm.

11. The separator of claim 10, wherein the adhesive tape region has a width in the range of 2mm to 4mm in the width direction of the substrate.

12. The separator according to claim 9, wherein the thickness of the strip region in the thickness direction of the substrate is in the range of 0.5 μm to 6 μm.

13. The separator according to claim 12, wherein the thickness of the strip region in the thickness direction of the substrate is in a range of 1 μm to 3 μm.

14. An electrode assembly, comprising a positive plate, a negative plate and a separator disposed between the positive plate and the negative plate, wherein the separator is the separator according to any one of claims 1 to 13, and the surface of the substrate on which the adhesive layer is disposed is attached to the positive plate and/or the negative plate.

15. A battery cell comprising the electrode assembly of claim 14.

16. A battery comprising the cell of claim 15.

17. An electric device comprising the battery of claim 16.

18. A method for producing a separator, for producing the separator according to any one of claims 1 to 13, comprising the steps of:

19. The method of manufacturing of claim 18, further comprising the steps of:

and adhering an adhesive tape to at least one side of the adhesive coating area along the width direction of the substrate, wherein the adhesive tape extends along the length direction of the substrate to form an adhesive tape area.