CN219309673U

CN219309673U - Roller and rolling device for pole piece of lithium ion battery

Info

Publication number: CN219309673U
Application number: CN202223580418.3U
Authority: CN
Inventors: 赵志立; 李�瑞; 纪影
Original assignee: Tianjin EV Energies Co Ltd
Current assignee: Tianjin EV Energies Co Ltd
Priority date: 2022-12-30
Filing date: 2022-12-30
Publication date: 2023-07-07
Anticipated expiration: 2032-12-30

Abstract

The utility model belongs to the technical field of battery production, and discloses a roller and a rolling device for a lithium ion battery pole piece. The lithium ion battery pole piece roller comprises a roller main body and a connecting shaft, wherein the connecting shaft is arranged at two ends of the roller main body, the roller main body is cylindrical, two ends of the roller main body are provided with multi-stage ladder-shaped reduction along the circumferential direction so as to form multi-stage ladder at two ends of the roller main body, the straight direction of the roller main body is gradually decreased to two ends of the roller main body, an included angle alpha is formed between the connecting surface of each adjacent ladder and the axis of the roller main body, and the included angle alpha is set to 30-60 degrees. The lithium ion battery pole piece roller can effectively prevent the pole piece from generating bright edges in the rolling process, greatly improves the processing quality of the pole piece, and reduces the reject ratio of the pole piece, thereby reducing the production cost of the pole piece.

Description

Roller and rolling device for pole piece of lithium ion battery

Technical Field

The utility model relates to the technical field of battery production, in particular to a roller and a rolling device for a lithium ion battery pole piece.

Background

After the lithium ion battery pole piece is coated and dried, the peeling strength of the active substance and the current collector foil is very low, and the active substance and the foil are required to be rolled so as to enhance the bonding strength of the active substance and the foil and prevent the active substance from peeling off in the processes of electrolyte soaking and battery use. Pole piece rolling is a procedure which is necessary in the manufacturing process of the lithium ion battery, and the purpose of rolling is to obtain the pole piece which accords with design parameters. The pole piece is ensured to meet the manufacturing requirements by monitoring the compaction density, thickness, peeling strength of the active substance and the foil after the pole piece is rolled, and the like. Meanwhile, the volume of the battery core can be compressed by rolling the pole piece, the energy density of the battery core is improved, the porosity among active substances, conductive agents and binders in the pole piece is reduced, the resistance of the battery is reduced, and the performance of the battery is improved.

The rolling device for rolling the lithium ion battery pole piece generally adopts two rollers, and the lithium ion battery pole piece passes through between the two rollers. In the rolling process, the roller is elastically bent, and the pressure at the two ends of the roller is increased, so that the edge compaction density of the material area is too high, and bright edges are formed. The problem of too high edge compaction density of a material area is solved by adjusting the convexity of a roller, but the problem of uneven edge compaction thickness cannot be avoided by only adjusting the convexity of the roller. Three continuous points of the 6mm skived area coated were measured with a micrometer having a diameter of 2mm, and the compaction density was greater closer to the edge, with a 1.15% difference between the two points. Meanwhile, the convexity of the roller is difficult to control, and if the convexity of the roller is too small, the edge overpressure cannot be avoided; if the convexity of the roller is too large, the deformation amount of the middle area of the convex roller is large, and warping is formed, so that the subsequent battery manufacturing process is influenced.

Therefore, improvements in the rolls and rolling devices for pole pieces of lithium ion batteries are needed to solve the above problems.

Disclosure of Invention

The utility model aims to provide a pole piece roller of a lithium ion battery, which solves the problem that the edge compaction density of a pole piece is too high to form a bright edge due to the fact that the pressure at two ends of the existing roller is increased when the existing roller is elastically bent.

To achieve the purpose, the utility model adopts the following technical scheme:

the lithium ion battery pole piece roller comprises a roller main body and a connecting shaft, wherein the connecting shaft is arranged at two ends of the roller main body, the roller main body is cylindrical, two ends of the roller main body are provided with multi-stage ladder-shaped reduction along the circumferential direction so as to form multi-stage ladder at two ends of the roller main body, the straight line of the roller main body is radial to the two ends of the roller main body gradually decreases, an included angle alpha is formed between the connecting surface of each adjacent ladder and the axis of the roller main body, and the included angle alpha is 30-60 degrees.

Alternatively, the length c of each cut-down region of the roll body is 5% -15% of the total length a of the roll body.

Alternatively, the roll body has a total cut-down thickness b of 1mm-3mm.

Alternatively, the number n of steps provided at one end of the roll body is 3-10.

Alternatively, the reduced thickness of a plurality of the steps is the same.

Alternatively, the reduced thickness of each step is 1/n×b.

Alternatively, the connection surface of the adjacent steps and the platform of the steps are rounded.

Alternatively, the radius R of the fillet is 0.1mm-0.3mm.

Alternatively, the included angle α is set to 45 °.

The utility model further aims to provide a pole piece rolling device for the lithium ion battery, which can prevent the edge of the pole piece from forming a bright edge when rolling the pole piece of the lithium ion battery.

the rolling device for the lithium ion battery pole piece comprises two rolling rolls for the lithium ion battery pole piece, wherein the two rolling rolls for the lithium ion battery pole piece are arranged in parallel to roll the lithium ion battery pole piece.

The beneficial effects are that:

according to the lithium ion battery pole piece roller, the two ends of the roller main body are subjected to multistage stepped reduction, and when the roller main body is elastically bent, enough space is reserved at the two ends of the roller main body to prevent overpressure. The reduction area is aligned with the coating thinning area of the pole piece, and the coating thinning area is stressed more uniformly in the rolling process by gradually increasing the reduction thickness on the roller main body, so that the pole piece is effectively prevented from generating bright edges in the rolling process, the processing quality of the pole piece is greatly improved, the reject ratio of the pole piece is reduced, and the production cost of the pole piece is reduced.

According to the rolling device for the lithium ion battery pole piece, provided by the utility model, by arranging the roller for the lithium ion battery pole piece, when the lithium ion battery pole piece is rolled, the edge of the pole piece can be prevented from forming bright edges, and the processing quality and the yield of the pole piece are improved.

Drawings

Fig. 1 is a schematic structural diagram of a lithium ion battery pole piece roller provided by an embodiment of the utility model;

FIG. 2 is an enlarged block diagram of FIG. 1 at A;

fig. 3 is a schematic diagram of an exemplary cut-out area of a lithium ion battery pole piece roll according to an embodiment of the present utility model.

In the figure:

100. a lithium ion battery pole piece roller; 110. a roll body; 120. and a connecting shaft.

Detailed Description

The utility model is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the utility model and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the structures related to the present utility model are shown in the drawings.

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

In the present utility model, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.

In the description of the present embodiment, the terms "upper", "lower", "left", "right", and the like are orientation or positional relationships based on those shown in the drawings, merely for convenience of description and simplicity of operation, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the utility model. Furthermore, the terms "first," "second," and the like, are used merely for distinguishing between descriptions and not for distinguishing between them.

As shown in fig. 1, the present embodiment provides a lithium ion battery pole piece roller 100 and a lithium ion battery pole piece rolling device including the lithium ion battery pole piece roller 100, where the lithium ion battery pole piece rolling device includes two lithium ion battery pole piece rollers 100, and the two lithium ion battery pole piece rollers 100 are arranged in parallel to roll a lithium ion battery pole piece. In the rolling working process, the lithium ion battery pole piece roller 100 can axially deform, so that the defects of pole piece bright edges, edge powder falling and the like caused by overlarge pressure at two ends of the lithium ion battery pole piece roller 100 are generated, the reject ratio of the pole piece is higher, and the production cost is influenced.

To solve the above problems, in this embodiment, the lithium ion battery pole piece roll 100 is improved, and referring to fig. 1 and 2, the lithium ion battery pole piece roll 100 includes a roll main body 110 and a connecting shaft 120, the connecting shaft 120 is disposed at two ends of the roll main body 110, and the roll main body 110 is installed through the connecting shaft 120. The roller main body 110 is cylindrical, the two ends of the roller main body 110 are provided with multi-stage ladder-shaped cuts along the circumferential direction so as to form multi-stage ladder at the two ends of the roller main body 110, the diameter of the roller main body 110 gradually decreases towards the two ends of the roller main body 110, an included angle alpha is formed between the connecting surface of the adjacent ladder and the axis of the roller main body 110, and the included angle alpha is set to be 30-60 degrees.

By performing multi-step reduction on both ends of the roll main body 110, when the roll main body 110 is elastically bent, a sufficient space is left at both ends of the roll main body 110 to prevent overpressure. The coating thinning area of the pole piece is aligned to the thinning area, and the stress of the coating thinning area in the rolling process is more uniform by gradually increasing the thickness of the roller main body 110, so that the pole piece is effectively prevented from generating bright edges in the rolling process, the processing quality of the pole piece is greatly improved, the reject ratio of the pole piece is reduced, and the production cost of the pole piece is reduced.

Alternatively, as shown in fig. 1 and 2, the length c of each cut-down region of the roll body 110 may be 5-15%, such as 6%, 8%, 10%, 12%, 14% or 15%, of the total length a of the roll body 110. The length c of the stepped reduction area is equal to the length of the coating and thinning area on the pole piece, and the reduction area corresponds to the coating and thinning area in the rolling process.

Alternatively, as shown in FIG. 2, the roll body 110 may have a total cut-down thickness b of 1mm-3mm. The actual value of the thickness b is reduced and can be reasonably selected within the range of 1mm-3mm according to the characteristics of the pole piece.

Measured by a micrometer with the diameter of 2mm, three continuous points of a thinned area with the diameter of 6mm are coated, the compaction density is greater when the thickness of the thinned area is closer to the edge, and the compaction density between two adjacent points is 1.15 percent different. Thus, the number of steps n provided at one end of the roll body 110 is 3 to 10, for example, 3, 4, 5, 6, 7, 8, 9 or 10.

Preferably, the reduced thickness of the plurality of steps is the same, i.e. the reduced thickness of each step is 1/n×b. And each step is uniformly cut, so that uneven pressure in the rolling process is prevented.

Alternatively, the setting of the angle α between the connecting surfaces of the adjacent steps and the axis of the roll body 110 should be controlled within the range of 30 ° -60 °, and the angle α is preferably set at 45 °. If the angle is too small, enough space cannot be left in the coating skiving area with a certain length to prevent the problem of edge overpressure caused by elastic deformation of the roller main body 110; if the angle is too large, the transition between the adjacent steps is not smooth enough, the problem that the pressure at the step with small diameter is small and the pressure at the step with large diameter is large can occur at the joint of the two steps in the rolling process, so that the uneven pressure in the rolling process is caused, and the rolling effect is influenced.

Optionally, the connection part between the connection surface of the adjacent steps and the platform of the steps is a round angle, and smooth transition between the steps is realized through the round angle. The radius R of the fillet is 0.1mm-0.3mm, for example 0.1mm, 0.2mm or 0.3mm.

In a preferred embodiment of the present utility model, as shown in fig. 3, the length c of the reduced area of the roll 100 for lithium ion battery pole piece is 6mm, the total reduced thickness b of the roll body 110 is 3mm, the reduced thickness of each step is 1mm, the radius R of the rounded corner where the connecting surface of the adjacent steps is connected to the platform of the steps is 0.2mm, and the angle α between the connecting surface of the adjacent steps and the axis of the roll body 110 is 45 °. Experiments prove that when the lithium ion battery pole piece roller 100 with the size in the preferred embodiment is adopted, three points are uniformly measured on the pole piece, and the compaction density values of the thinned area after pole piece rolling are respectively 1.548g/cm ³ 、1.549g/cm ³ And 1.549g/cm ³ . In the comparative example, the prior lithium ion battery pole piece roller (i.e. without step reduction) is adopted, and the compaction density value of the skived area after pole piece rolling is 1.600g/cm respectively ³ 、1.586g/cm ³ And 1.567g/cm ³ With the lithium ion battery pole piece roll 100 of this embodiment, the compaction density at all three measurement points is the sameThe reduction and the more even compaction density value distribution fully prove that the lithium ion battery pole piece roller 100 provided by the embodiment can play a role in preventing overvoltage, enabling the coating skiving area to be stressed more evenly in the rolling process, and effectively preventing the pole piece from generating bright edges in the rolling process.

It is to be understood that the above examples of the present utility model are provided for clarity of illustration only and are not limiting of the embodiments of the present utility model. Various obvious changes, rearrangements and substitutions can be made by those skilled in the art without departing from the scope of the utility model. It is not necessary here nor is it exhaustive of all embodiments. Any modification, equivalent replacement, improvement, etc. which come within the spirit and principles of the utility model are desired to be protected by the following claims.

Claims

1. Lithium ion battery pole piece roll, its characterized in that, lithium ion battery pole piece roll includes roll main part (110) and connecting axle (120), connecting axle (120) set up in the both ends of roll main part (110), roll main part (110) set up to cylindric, the both ends of roll main part (110) all set up multistage echelonment along circumference and reduce, in order to be in the both ends of roll main part (110) form multistage ladder, the straightness of roll main part (110) to the both ends of roll main part (110) progressively decrease, adjacent be contained angle alpha between the junction surface of ladder with the axis of roll main part (110), contained angle alpha sets up to 30 ~ 60.

2. The lithium ion battery pole piece roll according to claim 1, characterized in that the length c of each cut-down region of the roll body (110) is 5% -15% of the total length a of the roll body (110).

3. The lithium ion battery pole piece roll according to claim 1, characterized in that the roll body (110) has a total reduced thickness b of 1mm-3mm.

4. A lithium ion battery pole piece roll according to claim 3, characterized in that the number of steps n provided at one end of the roll body (110) is 3-10.

5. The lithium ion battery pole piece roll of claim 4, wherein the reduced thickness of the plurality of steps is the same.

6. The lithium ion battery pole piece mill roll of claim 5, wherein the reduced thickness of each step is 1/n x b.

7. The lithium ion battery pole piece roll of any of claims 1-6, wherein the connection surface adjacent the step is rounded at the juncture with the plateau of the step.

8. The lithium ion battery pole piece roll of claim 7, wherein the radius R of the rounded corners is 0.1mm-0.3mm.

9. The lithium ion battery pole piece roll according to any of the claims 1-6, characterized in that the angle α is set to 45 °.

10. The rolling device for the lithium ion battery pole piece is characterized by comprising two rolling rolls for the lithium ion battery pole piece according to any one of claims 1 to 9, wherein the two rolling rolls for the lithium ion battery pole piece are arranged in parallel to roll the lithium ion battery pole piece.