CN115810786A - Roller, winding device, cell winding method, electrochemical device, and electronic apparatus - Google Patents

Abstract

The application relates to a roller, a winding device, a battery winding method, an electrochemical device and electronic equipment. Wherein, the roller member includes a roller main body and an active member, the active member is located on the outer wall of the roller main body, and has an active substance, and the active member can make the active substance before the positive pole piece is wound on the winding shaft. The positive electrode active material that is in contact with the positive electrode sheet.

Description

Roller, winding device, cell winding method, electrochemical device, and electronic equipment

technical field

The application relates to a roller, a winding device, a battery winding method, an electrochemical device and an electronic device.

Background technique

The winding structure is one of the commonly used cell structures for secondary batteries, and its advantages are high production efficiency and low cost.

However, there are safety risks in the winding structure of the battery, and even short-circuit failure and other problems.

Contents of the invention

In view of the problems existing in the background technology, the purpose of this application is to provide a roller, a winding device, a battery winding method, an electrochemical device and electronic equipment, to solve the safety problem of the wound battery and improve the electrochemical performance. device and reliability of electronic equipment.

In a first aspect, the present application provides a roller element, the roller element comprising: a roller main body; an active element located on the outer wall of the roller main body; wherein, the active element has an active substance, and the active element can convert the The active substance is brought into contact with the roll before the roll is wound around the winding shaft.

In the technical solution of the embodiment of the present application, it is convenient to change the properties of the wound material. For example, the roller is suitable for the winding device of the wound battery, and the active part of the roller is used to contact the active material on the positive pole Positive electrode active material, increase the CB value (Cell Balance, the ratio of the active material capacity of the negative electrode to the active material capacity of the positive electrode) at the corner position of the inner ring of the battery cell, which can effectively avoid the problem of lithium precipitation and solve the problem of wound-type batteries. To solve the safety problem, improve the reliability of electrochemical devices and electronic equipment, and adopt the structure of the roller, which has little impact on the winding production process, and retains the advantages of high production efficiency and low cost of the winding cell.

In some embodiments, the active member includes a first chamber containing the active substance, the chamber wall of the first chamber has capillary pores to hold the active substance in the first chamber indoor. With the capillary structure, it is possible to control the timing at which the active substance contacts the wound material with a simple structure.

In some embodiments, the first chamber has a communication portion for communicating with a pressure source, and when the pressure source applies pressure to the active substance, the active substance flows out from the capillary to contact the active substance. the windings. The structure in which the pressure source communicates with the first chamber is adopted, the structure is simple, and the influence on the properties of the active substance itself is small, which improves the reliability of the effect of the active substance on the active material.

In some embodiments, the shape of the capillary hole is one or more of circular or polygonal. Through the flexible setting of the shape of the capillary hole, it can ensure that the active substances are fully absorbed by the corner positions of the inner circle of various areas and shapes. touch.

In some embodiments, the viscosity of the active substance is 0.5-8 mPa/s, and the active substance within this viscosity range can be easily accommodated in the first chamber.

In some embodiments, the active substances include one or more of water and N-methylpyrrolidone. The above active substances are commonly used substances in the production of electric cells and are easy to obtain.

In some embodiments, the inner wall and the outer wall of the roller body define a second chamber, the second chamber contains the active substance, and the second chamber communicates with the first chamber to provide The first chamber supplies the active substance, so that the self-structure of the roller body can be used to store the active substance, which not only facilitates the delivery of the active substance to the first chamber of the active member, but also improves the winding device including the roller. The high level of integration makes the winding device compact.

In some embodiments, the active part includes an adhesive area, and the adhesive area is provided with an adhesive paper, the adhesive paper includes a base and a back adhesive bonded to the base, and the active substance includes the back adhesive glue. The adhesive paper structure is adopted, which is easy to arrange on the main body of the roller, making the structure of the roller parts simple.

In some embodiments, the shape of the roller body is circular or polygonal. By flexibly setting the shape of the roller body, it can be ensured that the shape of the bonding area of the active part matches the shape of the wound battery. Full contact with corners of inner rings of various areas and shapes.

In some embodiments, the adhesive includes any pressure-sensitive adhesive with a 180-degree plane peel strength>0.01N/mm, and the substrate is made of polyethylene terephthalate (PET), polypropylene (PP), fusible polytetrafluoroethylene (PFA), the above adhesives have a good bonding effect on the positive electrode active material, and the cost of the substrate is low and easy to obtain.

In the second aspect, the present application provides a winding device, the winding device includes: a winding shaft for winding the winding object; the roller member as described in the first aspect, wherein the roller member is located at the The upstream side of the winding shaft; the intermittent action device is connected to the roller, so that the active part of the roller can intermittently contact the active substance before the roll is wound on the winding shaft. the windings.

In the technical solution of the embodiment of the present application, the synergistic effect of the winding shaft, the roller and the intermittent actuation device is adopted, and the winding device realizes the convenience of changing the properties of the winding, such as contacting the active substance with the positive electrode of the positive electrode sheet. The active material can improve the CB value of the corner position of the inner ring of the battery, which can effectively avoid the problem of lithium precipitation, solve the safety problem of the wound battery, and improve the reliability of the electrochemical device and electronic equipment. The structure has little influence on the winding production process, and retains the advantages of high production efficiency and low cost of the winding cell.

In some embodiments, the winding device includes a plurality of pressing roller positions, and at least one of the plurality of pressing roller positions is correspondingly provided with the roller element. In this way, the roller can make full use of the installation structure of the winding device corresponding to the pressure roller, without major changes to the original winding device, and the solution is easy to implement.

In some embodiments, the roller part is part of the roller part described in the first aspect, and the intermittent actuation device includes a position adjustment mechanism, which can intermittently adjust the position of the roller part between the back glue and the roller part. The windings are contacted to bond portions of the winding material away from the windings.

In some embodiments, the roller is part of the roller described in the first aspect, and the intermittent actuation device includes a pressure source capable of applying pressure to the active substance intermittently, so that the active substance intermittently Flows from the capillary to contact the winding.

In the third aspect, the present application provides a battery winding method, the battery winding method adopts the roller as described in the first aspect, and the active substance acts on the positive electrode activity of the positive electrode sheet to be wound. Material.

In some embodiments, when the positive pole piece being wound corresponds to the corner position of the inner circle of the positive pole piece, the active material of the roller member is in contact with the corner position of the inner circle; When the wound positive pole piece corresponds to a position other than the corner position of the inner ring of the positive pole piece, the active material of the roller member is not in contact with the positive pole piece, thus improving the efficiency of the winding process, The loss of battery capacity is also avoided as much as possible.

In some embodiments, when the positive pole piece to be wound is the innermost positive pole piece of the cell corresponding to the corner position of the inner circle of the innermost positive pole piece, the roller has all The active substance is in contact with the corner position of the inner circle; when the positive pole piece that is being wound corresponds to a position other than the corner position of the inner circle of the innermost positive pole piece, the roller has The active substance is not in contact with the positive pole piece, so that the efficiency of the winding process can be further improved, and the loss of battery capacity can be further avoided.

In some embodiments, it is characterized in that, when the positive pole piece being wound corresponds to the corner position of the inner circle of the positive pole piece, the roller member has the active substance in contact with the corner position of the inner circle. The contact time is 1s-2min, in order to take into account the efficiency of the winding process and the sufficient contact time between the active substance and the positive electrode active material of the positive electrode sheet.

In a fourth aspect, the present application provides an electrochemical device, which includes a positive pole piece, a negative pole piece, a separator, and an electrolyte, and the positive active material of the positive pole piece of the electrochemical device has a first positive electrode The active material region, the second positive electrode active material region, the activity of the first positive electrode active material region is 0.5%-100% less than the activity of the second positive electrode active material region.

In the technical solution of the embodiment of the present application, the electrochemical device can effectively avoid the problem of lithium deposition in the wound battery cell, solve the safety problem, and improve the reliability of operation.

In a fifth aspect, the present application provides an electronic device, the electronic device comprising the electrochemical device as described in the fourth aspect.

The above description is only an overview of the technical solution of the present application. In order to better understand the technical means of the present application, it can be implemented according to the contents of the description, and in order to make the above and other purposes, features and advantages of the present application more obvious and understandable , the following specifically cites the specific implementation manner of the present application.

Description of drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiment. The drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the application. Also, the same reference numerals are used to denote the same components throughout the drawings. In the attached picture:

FIG. 1 is a schematic diagram of a winding device according to an embodiment of the present application.

Fig. 2 is a schematic diagram of a roller member according to an embodiment of the present application.

Fig. 3 is a schematic diagram of a winding device according to another embodiment of the present application.

Fig. 4 is a schematic diagram of a winding device according to another embodiment of the present application.

FIG. 5 is a schematic diagram of an electrochemical device according to an embodiment of the present application.

Reference signs:

10-winding device;

1-roller, 2-winding shaft, 3-intermittent action device, 100-winding;

11-roller body, 111-outer wall, 112-inner wall, 113-second chamber, 12-acting part, 121-first chamber, 122-bonding area, 1210-capillary hole, 1220-tape, 13- Action substance;

Positive pole piece 4, innermost positive pole piece 401, battery cell 5, negative pole piece 6;

Corner positions 40 and 4010 of the inner circle, linear structure parts 4011 and 4012 of the innermost positive pole piece, linear structure parts 51 and 52 of the battery, first positive electrode active material region 41 and second positive electrode active material region 42 .

Detailed ways

Embodiments of the technical solutions of the present application will be described in detail below in conjunction with the accompanying drawings. The following examples are only used to illustrate the technical solution of the present application more clearly, and therefore are only examples, rather than limiting the protection scope of the present application.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field of the application; the terms used herein are only for the purpose of describing specific embodiments, and are not intended to To limit this application; the terms "comprising" and "having" and any variations thereof in the specification and claims of this application and the description of the above drawings are intended to cover a non-exclusive inclusion.

In the description of the embodiments of the present application, technical terms such as "first" and "second" are only used to distinguish different objects, and should not be understood as indicating or implying relative importance or implicitly indicating the number, specificity, or specificity of the indicated technical features. Sequence or primary-secondary relationship. In the description of the embodiments of the present application, "plurality" means two or more, unless otherwise specifically defined.

Reference herein to an "embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present application. The occurrences of this phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is understood explicitly and implicitly by those skilled in the art that the embodiments described herein can be combined with other embodiments.

In the description of the embodiment of the present application, the term "and/or" is only a kind of association relationship describing associated objects, which means that there may be three kinds of relationships, such as A and/or B, which may mean: A exists alone, and A exists at the same time and B, there are three cases of B alone. In addition, the character "/" in this article generally indicates that the contextual objects are an "or" relationship.

In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two), similarly, "multiple groups" refers to more than two groups (including two), and "multiple pieces" refers to More than two pieces (including two pieces).

In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical" "Horizontal", "Top", "Bottom", "Inner", "Outer", "Clockwise", "Counterclockwise", "Axial", "Radial", "Circumferential", etc. indicate the orientation or positional relationship based on the drawings Orientation or positional relationship is only for the convenience of describing the embodiment of the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as an implementation of the present application. Example limitations.

In the description of the embodiments of this application, unless otherwise clearly specified and limited, technical terms such as "installation", "connection", "connection" and "fixation" should be interpreted in a broad sense, for example, it can be a fixed connection or a fixed connection. Disassembled connection, or integration; it can also be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediary, and it can be the internal communication of two components or the interaction relationship between two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the embodiments of the present application according to specific situations.

At present, the winding structure is one of the commonly used cell structures for secondary batteries, and its advantages are fast production efficiency and low cost. However, there are safety risks in the winding structure of the battery, and even short-circuit failure and other problems.

The inventors of the present application have found that one of the reasons why the electric core of the winding structure has a safety risk is that, for the electric core of the winding structure, the CB value (Cell Balance, which is the activity of the negative electrode) at the corner position of the inner ring is The ratio of the material capacity to the active material capacity of the positive electrode) is lower than the rest of the position, which leads to the problem of lithium deposition at the corner of the inner ring during the charging process, which leads to the safety risk of the wound-type battery cell, and even Problems such as short circuit failure occur.

In order to solve the problem of lithium deposition at the corner of the inner ring, so as to solve the safety problem of wound-type batteries, improve the performance and reliability of electrochemical devices and electronic equipment, while retaining the fast production efficiency and low cost of wound-type batteries advantages, the inventor has designed a roller after in-depth research, by setting an active member with an active substance on the outer wall of the roller body of the roller, when the positive pole piece that is being wound corresponds to the inner ring of the positive pole piece At the corner position, the active substance is contacted with the positive active material of the positive pole piece before the positive pole piece is wound on the winding shaft, so as to reduce the activity of the positive active material at the corner position of the inner ring and increase the CB value at the corner position of the inner ring , thus effectively avoiding the problem of lithium precipitation, so as to solve the safety problem of wound batteries, and improve the performance and reliability of electrochemical devices and electronic equipment.

At the same time, since the winding device of the existing winding-type battery cell generally has a plurality of pressure roller structures, the designed roller can be installed using the installation and positioning structure corresponding to the original pressure roller, and can be installed on the positive pole. The operation of the pole piece before winding also makes the cost of the winding device and winding method using the designed roller parts low, and retains the advantages of fast production efficiency and low cost of the winding structure of the battery cell.

The roller disclosed in the embodiment of the present application can be used, but not limited to, for the winding process of the wound-type cell of the lithium-ion battery, and can also be applied to other rolls that contact the active substance with the wound to change the wound. winding process.

According to some embodiments of the present application, referring to FIG. 1 to FIG. 4 , the present application provides a roller member 1 , including a roller main body 11 and an active member 12 . The treatment member 12 is located on the outer wall 111 of the roller main body 11, and the treatment member 12 has the treatment substance 13. As shown in FIG. 1 and FIG. The winding 100 was previously touched.

The roller member 1 is a roller member capable of rolling, and the roller main body 11 is a roller-shaped part that can roll around an axis.

The treatment member 12 refers to a part in the roller member 1 that acts on the wound material in contact with the treatment substance 13 . Compared with the roller body 11 of the roller element 1, the roller body 11 is a structural member that realizes the rolling function of the roller element 1 itself, while the action element 12 is a component with a specific function that acts on the winding material 13 .

The treatment part 12 is located on the outer wall 111 of the roller main body 11, which means that the treatment part 12 can be a part of the outer wall of the roller main body 11 as shown in FIG. 1 or FIG. The treatment member 12 can be arranged on the basis of the complete contour line of the outer wall 111 and the treatment member 12 can be superimposed on a certain area of the contour line of the outer wall 111 .

The wound object 100 is generally a strip, such as a positive electrode sheet of a lithium-ion battery, and the strip-shaped positive electrode sheet is wound by the winding shaft 2 to form a part of a wound-type battery cell.

"The winding object 100 is wound before the winding shaft 2" refers to the process of tape running before the winding object is wound.

The active substance 13 refers to the contact with the winding 100 to cause a change in the properties of certain regions of the winding. For example, for the positive pole piece where the winding is a wound-type electric core, the active substance can be a material that reduces the activity of the positive pole, acting on the corner position of the inner circle of the positive pole piece, so that the activity of the corner position of the inner circle of the positive pole piece Material capacity is reduced. The manner in which the active substance 13 changes the properties of the winding can be, for example, a physical change, such as peeling off the positive electrode active material of the positive electrode sheet to reduce the activity, or it can also be a chemical change, such as the interaction between the active substance and the positive active material. The chemical reaction reduces the activity of the positive electrode active material of the positive electrode sheet.

Here, the active substance 13 of the active member 12 is in contact with the winding object 100, which means that the active substance 13 itself is in contact with the winding object 100 so that the active substance 13 acts on the winding object, and it does not limit whether the structure of the active member 12 itself is consistent with The windings 100 are in contact.

By setting the active part 12 and the active substance 13 on the roller part 1, it is convenient to change the properties of the wound object 100. For example, the roller part 1 is suitable for the winding device of the wound electric core. The active substance 13 is in contact with the positive electrode active material of the positive electrode sheet, which increases the CB value at the corner position of the inner ring of the cell, can effectively avoid the problem of lithium deposition, solve the safety problem of the wound cell, and improve the electrochemical device and electronic performance. The reliability of the equipment, while adopting the structure of the roller, realizes the effect of the tape running process on the winding before winding, has little impact on the winding production process, and retains the existing production efficiency of the winding cell Advantages of high and low cost.

According to some embodiments of the present application, optionally, please continue to refer to FIG. 1 and FIG. 2 , the treatment member 12 includes a first chamber 121 containing the treatment substance 13 . As shown in FIG. 2 , the chamber wall of the first chamber 121 has capillary pores 1210 to keep the active substance 13 inside the first chamber 121 .

The capillary hole 1210 means that when the active substance 13 is a liquid, due to the capillary phenomenon, the pore diameter of the capillary hole 1210 is small enough to make the surface tension of the liquid active substance 13 large enough to make the active substance 13 under a set temperature or pressure. remain in the first chamber 121 without flowing out. The diameter of capillary 1210 may be 100 μm-500 μm.

Through the structure of the capillary 1210, the liquid active substance 13 can be kept inside the first chamber 121 without contacting the winding 100 without contacting the winding 100 through a simple structure. When the 100 is wound to the area where the properties need to be changed, the active substance 13 is then brought into contact with the wound object 100 to accurately control the timing of the active substance contacting the wound object.

According to some embodiments of the present application, optionally, the first chamber 121 has a communication portion for communicating with a pressure source. When the pressure source applies pressure to the first chamber 121 , the active substance 13 flows out from the capillary 1210 to contact the winding 100 .

The communication portion of the first chamber 121 refers to a component or structure that communicates with a pressure source, such as a hole or a pipeline structure. A pressure source refers to an object that can exert pressure on an object, such as a pneumatic cylinder, a hydraulic cylinder, and the like. Due to the pressure of the pressure source, the active substance 13 originally held in the first chamber 121 through the capillary action of the capillary 1210 can flow out from the capillary 1210 to contact the wound object 100 .

The active substance 13 is released and flowed out from the first chamber 121 by applying pressure. The structure is simple and has little influence on the properties of the active substance itself, which improves the reliability of the active substance on the winding.

According to some embodiments of the present application, optionally, the shape of the capillary hole 1210 is one or more of circular or polygonal. Referring to FIG. 2 , the capillary holes 1210 may all be circular in shape. However, it can also be polygonal, or partly circular and partly polygonal.

The polygon here is a polygon in a generalized sense, including a planar figure composed of three or more line segments connected end to end, such as triangles, squares, rectangles, trapezoids, etc., as well as arcs and straight lines. Composed of graphics, such as fan and so on. Through the flexible setting of the capillary shape, it can ensure that the active substance needs to act on the area of the winding that needs to be in contact with various areas and shapes. For example, the corner position of the inner ring of the positive pole piece can achieve sufficient contact, avoiding the existence of certain edge positions. A dead zone where the substance of action cannot come into contact.

According to some embodiments of the present application, optionally, the viscosity of the active substance 13 is 0.5-8 mPa/s.

Viscosity here, also known as viscosity, can also be called viscosity coefficient, which is a physical quantity to measure the viscosity of fluid. Two parallel liquid layers with a distance of dx in the fluid, due to internal friction, there is a velocity gradient dv/dx between the liquid layers perpendicular to the flow direction. When the velocity gradient is 1 unit, the viscosity generated on the contact surface S of adjacent flow layers Hysteresis F (also known as internal friction).

Using the active substance in the above viscosity range, the corresponding pore size of the capillary 1210 is easy to process, so that the active substance 13 is easily accommodated in the first chamber 121 .

According to some embodiments of the present application, optionally, the active substance 13 includes one or more of water and N-methylpyrrolidone (NMP). The variety here, ie, the active substance 13, can contain both water and N-methylpyrrolidone. The active substance 13 using the above ingredients is a commonly used substance in the production of batteries for secondary batteries. For example, N-methylpyrrolidone is a polar solvent. In the production of secondary batteries, it is often used as a dispersant, so it is easy to obtain. Water is the most common raw material for production. Therefore, the use of the above-mentioned active substance 13 can not only reduce the activity of the positive electrode active material of the positive electrode sheet, but also reduce the material cost.

According to some embodiments of the present application, optionally, as shown in FIG. 113 communicates with the first chamber 121 to supply the action substance 13 to the first chamber 121 .

The inner wall 112 of the roller body 11 refers to the wall surface of the inner ring of the drum-shaped roller body 11 , and a cavity structure is formed between the inner wall 112 and the outer wall 111 , defining a second chamber 113 . The second chamber 113 accommodates the active substance 13 and serves as a storage container for the active substance 13 of the first chamber 121 . The structure that the second chamber 113 communicates with the first chamber 121 can be a hole or pipeline structure. Contrary to the capillary hole 1210, the aperture of the hole connecting the second chamber 113 and the first chamber 121 should be large enough to Capillary action is overcome, so that the active substance 13 can enter the first chamber 121 smoothly from the second chamber 113 .

In this way, the self-structure of the roller body 11 can be used to store the active substance 13, which facilitates the delivery of the active substance to the first chamber 121 of the active member, so that the supply of the active active substance 13 is sufficient, and there is no need to frequently add the active substance 13 to the active member 12. The operating efficiency of the roller 1 is improved, and in addition, there is no need to arrange a storage device and a transport mechanism for the active substance 13 outside the roller 1, which improves the integration of the winding device including the roller 1, making the winding device compact in structure .

According to some embodiments of the present application, optionally, as shown in FIG. 3 and FIG. 4 , the effect member 12 includes an adhesive area 122, and the adhesive area 122 is provided with an adhesive paper 1220, and the adhesive paper 1220 includes a base and is bonded to The backing adhesive of the substrate, which the active substance 13 comprises.

Adhesive area 122 refers to the area where the active part 12 is used to set the adhesive tape 1220. The width of the adhesive tape 1220 can be 1mm-2mm, and the function is to bond and peel off the material in a certain area of the winding object 100. Around things. For example, the positive active material at the corner of the inner ring of the positive electrode sheet is bonded to the adhesive paper 1220 and separated from the positive electrode sheet. The base of the adhesive paper 1220 can be arranged on the bonding area 122 of the active part 12 by bonding, and the back glue of the adhesive paper 1220 is located on the outer surface of the roller part 1. After the back glue contacts the positive active material, the positive active material is removed from the roller. The positive pole piece is peeled off, so that the activity of the corresponding position of the positive pole piece is reduced.

The structure of adhesive tape 1220 is easy to arrange on the roller main body 11, so that the structure of the roller part 1 is simple. Comparing the structure shown in Figure 1 and Figure 2 that uses the first chamber 121 to accommodate the active substance 13, the structure using adhesive tape only needs to set the bonding area, and even the bonding area can be directly selected from the roller of the roller body 11 As part of the shape profile, there is no need to specially construct the structure of the first chamber and the corresponding capillary pores.

It can be understood that although Fig. 1 and Fig. 2, Fig. 3 and Fig. 4 respectively show that the active part 12 of the roller part 1 is the structure of the first chamber 121 with capillary holes 1210, or has the bonding area 122 and glue The structure of the paper 1220 does not mean that the two structures can only be provided in one roller 1 alternatively, for example, two structures can also be provided in the same roller 1, for example, they are respectively arranged in the circumferential direction of the roller 1 The structure of the first chamber 121 having the capillary hole 1210 , and the structure having the bonding area 122 and the adhesive tape 1220 together constitute the effect member 12 .

According to some embodiments of the present application, optionally, as shown in FIG. 3 and FIG. 4 , the shape of the roller body 11 is circular or polygonal. The polygon here is a polygon in a generalized sense, including a planar figure composed of three or more line segments connected end to end, such as triangles, squares, rectangles, trapezoids, etc., as well as arcs and straight lines. Composed of graphics, such as fan and so on. Through the flexible setting of the shape of the roller main body 11, it can be ensured that the shape of the bonding area of the active part matches the shape of the wound battery, and the adhesive tape 1220 can better fit the corner position of the inner ring that needs to be acted on, so as to Fully contact the positive electrode active material to peel it off.

According to some embodiments of the present application, optionally, the back glue includes any pressure-sensitive adhesive with a 180° plane peel strength>0.01N/mm, and the material of the substrate is polyethylene terephthalate (PET), Polypropylene (PP), fusible polytetrafluoroethylene (PFA).

The performance of the 180° plane peel strength > 0.01N/mm here is tested according to the national standard GB2792-1998 "Test Method for 180° Peel Strength of Pressure-Sensitive Adhesive Tape". The material of the substrate may be any one of polyethylene terephthalate (PET), polypropylene (PP), and fusible polytetrafluoroethylene (PFA).

Using the adhesive with the above performance parameters, the inventors have found through in-depth research that the positive active material can be effectively peeled off from the corner of the inner ring of the positive electrode sheet, and the above substrate materials are low in cost and easy to obtain.

According to some embodiments of the present application, as shown in FIG. 1 and FIG. 3 , the present application also provides a winding device 10 , including a roller 1 , a winding shaft 2 and an intermittent operation device 3 . The roller part 1 is the roller part described in any of the above schemes, the winding shaft 2 is used for winding the winding object 100, the roller part 1 is located on the upstream side of the winding shaft 2, and the intermittent motion device 3 is connected to the roller part 1, so that The action member 13 of the roller member 1 can intermittently contact the action substance 13 to the winding material before the positive electrode sheet is wound on the winding shaft.

The roller part 1 is located on the upstream side of the winding shaft 2, that is, the roller part 1 is a part corresponding to the previous process of the corresponding process of the winding shaft 2, and the contact between the roller part 1 and the winding object 100 is that the winding object 100 is on the winding shaft 2 In the preceding process step of winding, specifically, during the tape-running process of the positive pole piece before being wound on the winding shaft 2 , it will first pass through the roller 1 and contact the active substance 13 .

Intermittent action device 3, "intermittent" here is a concept corresponding to "continuous", which refers to intermittent action so that the active member 12 also acts on the winding object 100 intermittently, and the active substance 13 intermittently contacts the winding The object 100, while the non-active part 12 keeps acting on the winding object 100 during the winding process, the inactivating object is always in contact with the winding object 100.

The winding device 10 has not only realized the convenience of changing the properties of the winding, for example, it is suitable for the winding of the winding type electric core, and the active part of the roller is used to contact the active material on the positive active material of the positive electrode sheet to improve the electric core. The CB value (Cell Balance, which is the ratio of the active material capacity of the negative electrode to the active material capacity of the positive electrode) at the corner position of the inner ring can effectively avoid the problem of lithium deposition, so as to solve the safety problem of the wound battery and improve the electrochemical performance. The reliability of the device and electronic equipment, while the winding device retains the advantages of high production efficiency and low cost of the winding process.

According to some embodiments of the present application, optionally, the winding device 10 includes a plurality of pressing roller positions P1 , P2 , and at least one of the plurality of pressing roller positions P1 , P2 is correspondingly provided with a roller member 1 .

The position of the pressing roller refers to the corresponding position of the pressing roller in the winding device. For example, as shown in FIG. 1 and FIG. 3 , the winding device includes two pressing roller positions P1 and P2. The pressing roller here refers to the pressing roller adopted by the winding device in the prior art. The pressing roller position P1 is correspondingly installed with a pressing roller, and the pressing roller position P2 is provided with a roller member 1 . It can be understood that the two pressing roller positions shown in FIG. 1 and FIG. 3 are only an example, and the winding device 10 may include more pressing roller positions.

In this way, the roller element 1 can make full use of the existing winding device corresponding to the position of the pressure roller and the installation of accessories, without requiring major changes to the existing winding device, and the solution is easy to implement.

According to some embodiments of the present application, optionally, the roller member 1 may be the roller member 1 shown in the embodiment shown in FIG. 3 and FIG. In the embodiment of the adhesive tape 1220, the corresponding intermittent action device 3 includes a position adjustment mechanism, which can intermittently adjust the position of the roller 1 until the back glue of the adhesive tape 1220 contacts the winding object 100 to partially wind the The material of the object is bonded away from the wound object.

The position adjustment mechanism may be a position adjustment mechanism for the roller main body 11, which displaces the roller part 1 as a whole, so that the roller main body 11 and the active part 12 are separated, for example, the roller main body 11 shown in FIG. 1 moves from position P3 to position P4 along the arrow , when the roller member 11 is at position P3, the roller main body 11 is not in contact with the winding object 100, and the adhesive tape 1220 set on the action member 12 is in contact with the winding object 100, and when the roller main body 11 is at position P4, the roller The adhesive tape 1220 of the main body 11 and the active part 12 is non-contact with the winding object 100 . In addition, the position adjustment mechanism can also be a rotation position adjustment mechanism for the treatment member 12. For example, as shown in FIG. To position A2, when the treatment member 12 is at the circumferential position A1, the roller main body 11 is not in contact with the wound object 100, the adhesive tape 1220 set on the treatment member 12 is in contact with the wound object 100, and when the treatment member 12 is at the circumferential position In A2, the active member 12 is not in contact with the winding object 100, and the roller body 11 is in contact with the winding object 100. At this time, it can continue to play a role similar to the pressure roller in the prior art on the winding object 100.

The position adjustment mechanism can be used to intermittently adjust the position of the roller 1 until the adhesive is in contact with the winding 100 to bond part of the winding material away from the winding, such as intermittently bonding the positive electrode sheet , to bond the positive electrode active material at the corner of the inner ring of the positive electrode sheet.

According to some embodiments of the present application, optionally, the roller member 1 may be the roller member 1 shown in the embodiment mode shown in FIG. 1 and FIG. 2 as an example, that is, the active member 12 of the roller member 1 includes In the embodiment of the first chamber 121, the corresponding intermittent action device 3 includes the pressure source described above, which can intermittently apply pressure to the active substance 13, so that the active substance 13 flows out from the capillary hole 1210 intermittently to contact the coil 100.

Applying pressure intermittently refers to intermittently increasing the pressure of the action substance 13 and then restoring it. Taking the acting substance 13 as water or N-methylpyrrolidone as an example, when the positive pole piece as the winding 100 is located at the corner of the inner ring, the pressure source increases the pressure to greater than 0.2 MPa, so that the acting substance 13 passes through the pores 1210 The positive electrode active material that flows out of contact with the corner of the inner ring, when the positive electrode piece is in the remaining position, the pressure returns to the default value, so that the active substance 13 is kept inside the first chamber 121 due to the action of the capillary hole 1210 and does not flow out, thereby Accurately control.

It can be understood that, for the embodiment shown in FIG. 1 and FIG. 2 as examples, the intermittent actuation device 3 may also include the position adjustment device described above. When the pressure source increases the pressure, the roller main body 11 is located at position P5, and when the pressure source returns to the pressure, the roller main body 11 is located at position P6; or, the roller main body 11 remains at position P5, and when the pressure source increases the pressure, the active member 12 is located at Circumferential position A3, when the pressure source returns to the pressure, the active member 12 is located at the circumferential position A4, at this time the roller main body 11 is in contact with the winding 100, and can continue to exert pressure on the winding 100 similar to that of the prior art. The role of the roller.

According to some embodiments of the present application, the present application also provides a battery winding method. Referring to FIG. 1 and FIG. Around things.

According to some embodiments of the present application, optionally, continue to refer to FIG. 1, FIG. 3, and in conjunction with FIG. When the corner position 40 of the inner circle of the positive electrode piece is in contact with the corner position 40 of the inner circle, the active substance 13 is in contact with the corner position 40 of the inner circle; The positive pole piece is non-contact.

The corner position 40 of the inner ring refers to the connection part of the positive pole piece due to winding. For example, the square cell structure shown in Figure 5 is an example. The corner position 40 of the inner ring is the two linear structural parts 51 connecting the cell 5 , 52 connecting parts. The positions other than the corner position 40 of the inner ring of the positive pole piece, such as shown in FIG. 5 , are the positions other than the corner position 40 of the inner circle of the positive pole piece.

In the winding process of the battery cell, the roller 1 is used to contact the active substance 13 with the positive pole piece 4 located at the corner position 40 of the inner ring, so as to increase the CB value at the corner position of the inner ring of the battery cell, and effectively avoid the problem of lithium precipitation , to solve the safety problem of wound-type batteries, and at the same time, it also retains the advantages of high production efficiency and low cost of the wound-type process.

According to some embodiments of the present application, optionally, continuing to refer to FIG. 5 , when the positive pole piece 4 being wound is the innermost positive pole piece 401 of the battery cell, it corresponds to the inner circle corner of the innermost positive pole piece 401 When the position is 4010, the active substance 13 is in contact with the corner position 4010 of the inner circle; when the wound positive pole piece 4 corresponds to a position other than the inner circle corner position 4010 of the innermost positive pole piece 401, the active substance 13 is in contact with the positive pole piece 401. The pole piece 4 is non-contact.

The innermost positive electrode sheet 401 , such as shown in FIG. 5 , refers to the innermost layer of positive electrode sheet for a structure including multi-layer positive electrode sheets 401 and 402 . Positions other than the inner circle corner position 4010 of the innermost positive pole piece 401, including the linear structure portions 4011, 4012 of the innermost positive pole piece 401, and pole pieces other than the innermost positive pole piece 401 Any position of 402, it can be understood that the multi-layer structure in FIG. 5 is only an example, and the number of layers of the pole piece of the battery can be more.

In this way, the efficiency of the winding process can be improved. The principle is that the inventors have found through in-depth research that the problem of lithium deposition in the innermost layer of the wound-type battery cell is the most serious. For some wound-type cells, only need Solving the lithium analysis problem of the innermost layer can solve the lithium analysis problem of the battery cell. Therefore, only the innermost positive pole piece needs to be contacted with the active substance 13 during winding, and the rest of the positive pole piece does not need to be contacted, which improves the efficiency of the winding process.

According to some embodiments of the present application, optionally, when the wound positive pole piece corresponds to the corner position of the inner circle of the positive pole piece, the action time of the active substance 13 on the corner position of the inner circle is 1s-2min.

The action time refers to the time when the action member 12 provides the action substance 13 in contact with the corner position of the inner ring. For example, for the embodiment shown in Fig. 1 and Fig. 2 as an example, the action substance 13 flows out from the capillary hole 1210 in the time range of 1s-2min From the first chamber 121 to the positive pole piece, for example, for the embodiment shown in Fig. 3 and Fig. 4 as an example, the adhesive paper 1210 with the active substance 13 is bonded to the positive pole piece in the time length range of 1s-2min, so that it can be Taking into account the efficiency of the winding process and the sufficient contact time between the active substance and the positive electrode active material of the positive electrode sheet.

According to some embodiments of the present application, the present application also provides an electrochemical device, as shown in FIG. 5 , including a positive pole piece 4 and a negative pole piece 6, and the positive active material of the positive pole piece 4 has a first positive pole active material Region 41 , the second positive electrode active material region 42 , the activity of the first positive electrode active material region 41 is 0.5%-100% less than the activity of the second positive electrode active material region 42 .

The electrochemical device may be a wound battery cell as shown in FIG. 5 , or a battery including the battery cell and a battery module composed of a plurality of batteries.

The positive electrode active material of the positive electrode sheet 4 has a first positive electrode active material region 41 and a second positive electrode active material region 42, which can be realized by the winding method described in the above embodiment, that is, the first active material region 42 is the corner position of the inner ring , the second active material area 42 is the rest of the position, in the winding process, the positive electrode active material at the corner position of the inner ring is used to remove the positive electrode active material by using the roller 1, for example, the deactivation material 13 is used, or the deactivation is added to the corner position of the inner ring Substance 13 to reduce the activity of the positive electrode active material at the corner of the inner ring. The activity of the first positive electrode active material region 41 is 0.5%-100% less than the activity of the second positive electrode active material region 42, which means that the capacity of the first positive electrode active material region 41 is less than the capacity of the second positive electrode active material region 42 under equal area conditions 0.5%-100%.

The manufacturing process of the battery cell can include:

Preparation of positive pole piece and negative pole piece: positive active main material, add a certain proportion of carbon black, add a certain proportion of binder, mix uniformly in a certain medium, and evenly coat both sides of the positive current collector. Negative electrode active main material, adding a certain proportion of carbon black, adding a certain proportion of binder, uniformly mixed in a certain medium, evenly coated on both sides of the negative electrode current collector.

For the prepared positive pole piece, the winding method introduced in the above embodiment is carried out every time the bare cell is wound, and the roller member 1 is used to contact the positive pole piece, thereby reducing the activity of the corner position of the positive pole piece .

Diaphragm preparation method: PP material dry method or PE material wet method prepares diaphragm, and obtains high crystallinity oriented film after high temperature annealing. The film is first stretched at low temperature to form micro-defects, and then the defects are pulled apart at high temperature to form micro-pores.

Electrolyte solution ratio: Electrolyte components include lithium salt (one or more of lithium hexafluorophosphate, lithium borate, lithium perchlorate), organic solvent (cyclic carbonate, chain carbonate), functional additives ( It can be unsaturated carbon compounds, sulfur-containing organic compounds, halogen-containing compounds).

Finally, the bare cells that have passed the action of the roller 1 are reshaped, assembled, shelled, liquid injected, formed, aged and other processes to produce finished hard shell cells.

The electrochemical device with the above structure can effectively avoid the problem of lithium precipitation, so as to solve the safety problem of the wound battery cell and improve the reliability of the electrochemical device.

According to some embodiments of the present application, the present application also provides an electronic device, including the electrochemical device described above.

Electronic devices include but are not limited to mobile digital devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems (such as large electric cabinets, household uninterruptible power supplies, etc.), etc.

In an optional example, the electronic device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. In order to meet the high power and high energy density requirements of this electronic device, a battery pack or battery module can be used.

As another example, an electronic device may be a mobile phone, a tablet computer, a laptop computer, and the like. The electronic equipment is generally required to be light and thin, and a secondary battery can be used as a power source.

According to the embodiment of the present application, referring to Fig. 1 and Fig. 2, the present application provides a roller part 1, the roller part 1 includes a roller main body 11 and an active part 12, and the active part 12 is a functional block, including a cavity structure The first chamber 121 is filled with the deactivated substance 13 of the functional solution that reduces the activity of the positive electrode in the first chamber 121. The first chamber 121 has capillary holes 1210. The corresponding position of the corner position of the inner ring of the pole piece is contacted at a time of 1s-2min, and the pressure on the inactivation substance 13 is increased to >0.2MPa, so that the inactivation substance 13 of the functional solution that reduces the activity of the positive electrode is squeezed out, and the The positive electrode active material of the positive electrode sheet contacts and reduces the activity of the positive electrode, reducing the activity of the corner position by 0.5% to 100%.

According to another embodiment of the present application, refer to Fig. 3 and Fig. 4, the active part 12 is a bonding area 122 with a block adhesive tape 1220, and during the winding process of each battery core, in the positive pole piece The corresponding position of the corner position of the circle is contacted for 1s-2min at a time, and the powder of the positive active material of the positive pole piece will be bonded to the rubber roller, so as to realize the reduction of the active material of the positive pole piece; reduce the activity of the corner position by 0.5 % to 100%. A receiving device may also be provided correspondingly in the winding device to collect waste adhesive tape.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit it; although the application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the application. All of them should be covered by the scope of the claims and description of the present application. In particular, as long as there is no structural conflict, the technical features mentioned in the various embodiments can be combined in any manner. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims (20)

1. A roller, characterized in that, comprising: roller body; an active member located on the outer wall of the roller body; In this case, the active element has an active substance, and the active element can bring the active substance into contact with the winding object before the winding object is wound on the winding shaft. 2. The roller element according to claim 1, wherein the active element comprises a first chamber containing the active substance, and the chamber wall of the first chamber has capillary holes to absorb the active substance. The active substance is held in the first chamber. 3. The roller member according to claim 2, wherein the first chamber has a communication portion for communicating with a pressure source, and when the pressure source applies pressure to the action substance, the action substance Flows from the capillary to contact the winding. 4. The roller member according to claim 2 or 3, characterized in that, the shape of the capillary holes is one or more of circular or polygonal. 5. Roll element according to any one of claims 2-4, characterized in that the viscosity of the active substance is 0.5-8 mPa/s. 6. The roller element according to any one of claims 2-5, characterized in that the active substance includes one or more of water and N-methylpyrrolidone. 7. The roller element according to any one of claims 2-6, wherein the inner wall and the outer wall of the roller body define a second chamber, the second chamber contains the active substance, the The second chamber communicates with the first chamber to supply the action substance to the first chamber. 8. The roller member according to any one of claims 1-7, wherein the active member comprises an adhesive area, and the adhesive area is provided with adhesive paper, and the adhesive paper includes a substrate and is bonded to The back glue of the substrate, the active substance includes the back glue. 9. The roller member according to any one of claims 1-8, characterized in that, the shape of the roller body is circular or polygonal. 10. The roller member according to claim 8 or 9, wherein the adhesive comprises any pressure-sensitive adhesive with a 180-degree plane peel strength>0.01N/mm, and the material of the substrate is polyparaphenylene Ethylene glycol diformate, polypropylene, fusible polytetrafluoroethylene. 11. A winding device, characterized in that it comprises: The winding shaft is used for winding the winding object; The roller element according to any one of claims 1-10, wherein the roller element is located on the upstream side of the winding shaft; The intermittent action device is connected to the roller, so that the active part of the roller can intermittently contact the active substance to the winding before the winding is wound on the winding shaft. 12 . The winding device according to claim 11 , comprising a plurality of pressing roller positions, wherein at least one of the plurality of pressing roller positions corresponds to the roller element. 13 . 13. The winding device according to claim 11 or 12, wherein the roller is the roller according to any one of claims 8-10, and the intermittent action device includes a position adjustment mechanism, which can The position of the roller is adjusted intermittently so that the adhesive is in contact with the roll to bond portions of the roll material away from the roll. 14. The winding device according to claim 11 or 12, wherein the roller is the roller according to any one of claims 2-7, and the intermittent actuating device includes a pressure source capable of intermittently Pressure is applied to the active substance so that the active substance intermittently flows out from the capillary pores to contact the coil. 15. A battery winding method, characterized in that the roller member according to any one of claims 1-10 is used to apply the active substance to the wound object to be wound. 16. The cell winding method according to claim 15, wherein the winding object is a positive pole piece, and when the positive pole piece being wound corresponds to the corner position of the inner ring of the positive pole piece, the The active substance is in contact with the corner of the inner circle; when the wound positive pole piece corresponds to a position other than the corner of the inner circle of the positive pole piece, the active substance is not in contact with the positive pole piece. 17. The cell winding method according to claim 16, wherein when the positive pole piece for winding is the innermost positive pole piece of the battery cell, it corresponds to the inner circle of the innermost positive pole piece At the corner position, the active substance is in contact with the corner position of the inner ring; when the positive electrode piece being wound corresponds to a position other than the corner position of the inner circle of the innermost positive electrode piece, the action The substance is not in contact with the positive pole piece. 18. The cell winding method according to claim 16 or 17, wherein when the positive pole piece being wound corresponds to the corner position of the inner circle of the positive pole piece, the active substance and the corner of the inner circle The action time of the position is 1s-2min. 19. An electrochemical device, comprising a positive pole piece and a negative pole piece, it is characterized in that, the positive active material of the positive pole piece of the electrochemical device has a first positive active material area, a second positive active material area, the The activity of the first positive electrode active material region is 0.5%-100% less than the activity of the second positive electrode active material region. 20. An electronic device, comprising the electrochemical device according to claim 19.

Images