Energy storage cell and preparation method thereof

Abstract

The embodiment of the invention relates to the field of energy storage, and provides an energy storage battery cell and a preparation method thereof, and the preparation method comprises the following steps: providing a film layer which is one of a positive plate, a diaphragm or a negative plate and has a first edge and a second edge; carrying out dispensing treatment on the film layer, so that the surface of the film layer is provided with a plurality of groups of glue point groups arranged along the first direction; the distribution density of the glue point groups decreases progressively along the direction from the second edge to the first edge; forming the other two of the positive plate, the diaphragm or the negative plate; winding the positive plate, the negative plate and the diaphragm from the second edge to the first edge; wherein the diaphragm is located between the positive plate and the negative plate, and the winding treatment is at least used for enabling glue points of the glue point group to be in a molten state and form an adhesive layer, so that the positive plate is fixed with the diaphragm or the diaphragm is fixed with the negative plate. The energy storage cell and the preparation method thereof provided by the embodiment of the invention at least can improve the yield of the energy storage cell and reduce the preparation cost.

Description

[0001] This application is a divisional application of the patent application with the application date of October 8, 2024, application number 202411396823.0, and invention name “Energy storage battery cell and its preparation method”. Technical Field

[0002] The embodiments of the present application relate to the field of energy storage, and in particular to an energy storage battery cell and a method for preparing the same. Background Art

[0003] In recent years, lithium-ion batteries have attracted great attention due to their excellent characteristics such as high energy density, high output voltage, low self-discharge rate, long service life, no memory effect and environmental friendliness. They have developed by leaps and bounds, their market share has continued to expand, and they have occupied a dominant position.

[0004] The development focus of the lithium-ion battery preparation process is on the cycle stability, preparation cost, and yield of the battery cell. Currently, there are two main ways to improve the energy density of the battery cell, one is the laminated type and the other is the wound type. Among them, the winding type is the most common way to improve the energy density. In the cross-section of the wound battery cell, the wound battery cell contains two parts, one is a flat extended area, and the other is a curved area. The core is made of multiple layers of thin film material. Tension will be generated during winding. If the tension is not large enough, it will cause problems such as bending, wrinkling, and even fracture. These defects increase the safety risk of the battery, especially in the bending area corresponding to the curvature, where the diaphragm is more prone to wrinkling. One of the current improvement measures is to release the stress of the diaphragm before preparing the lithium battery. This method is costly and will pollute the environment. The second current improvement measure is to change the structure of the crystalline and amorphous regions of the diaphragm to enhance the diaphragm's anti-wrinkle ability, but this may introduce other side effects, such as causing excessive self-discharge of the lithium battery, or the high modulus diaphragm may cause the lithium battery cell to be more prone to "S"-shaped deformation during recycling.

[0005] Therefore, there is an urgent need for a method for preparing an energy storage cell that can fix the diaphragm, the positive electrode sheet, and the negative electrode sheet to each other, so as to improve the yield of the energy storage cell and reduce the preparation cost. Summary of the Invention

[0006] The embodiments of the present application provide an energy storage battery cell and a method for preparing the same, which at least helps to improve the yield of the energy storage battery cell and reduce the preparation cost.

[0007] According to some embodiments of the present application, on the one hand, embodiments of the present application provide a method for preparing an energy storage battery cell, including: providing a film layer, wherein the film layer is one of a positive electrode sheet, a diaphragm or a negative electrode sheet, and the film layer has a first edge and a second edge arranged opposite to each other along a first direction; performing a glue dot treatment on the film layer so that the surface of the film layer has multiple groups of glue dots arranged along the first direction; the distribution density of the glue dot groups decreases along the direction from the second edge to the first edge; forming the positive electrode sheet, the diaphragm or the other two of the negative electrode sheet; performing a winding treatment on the positive electrode sheet, the negative electrode sheet and the diaphragm, and performing the winding treatment from the second edge toward the first edge; wherein the diaphragm is located between the positive electrode sheet and the negative electrode sheet, and the winding treatment is at least used to make the glue dots of the glue dot group molten and form an adhesive layer to fix the positive electrode sheet to the diaphragm and / or to fix the diaphragm to the negative electrode sheet.

[0008] In some embodiments, the film layer also has two third edges arranged opposite to each other along the second direction, and the two ends of each third edge are respectively connected to the first edge and the second edge; during the process of dispensing glue on the film layer, from the center of the film layer in the second direction toward the third edge, in the same glue point group, the distribution density within the glue point group increases.

[0009] In some embodiments, along the second direction and pointing to the third edge, the spacing between adjacent glue dots in the same glue dot group decreases; and / or, along the second direction and pointing to the third edge, the size of the glue dots in the same glue dot group increases.

[0010] In some embodiments, the glue dot group includes: a first glue dot group near the first edge and a second glue dot group near the second edge, the size of the first glue dot in the first glue dot group is smaller than the size of the second glue dot in the second glue dot group; and / or, the first spacing between adjacent first glue dots in the first glue dot group is greater than the second spacing between adjacent second glue dots in the second glue dot group.

[0011] In some embodiments, the ratio of the first spacing to the second spacing is 1.03 to 1.3.

[0012] In some embodiments, the ratio of the total area of the orthographic projections of the plurality of glue dot groups on the film layer to the surface area of the film layer is 10% to 14%.

[0013] In some embodiments, the process steps of the winding treatment include: hot winding treatment and cold pressing treatment, the hot winding treatment is used to make the glue points of the glue point group molten and form an adhesive layer to fix the positive electrode sheet to the diaphragm and / or to fix the diaphragm to the negative electrode sheet; the cold pressing treatment is used to fit the positive electrode sheet, the negative electrode sheet and the diaphragm together.

[0014] In some embodiments, before the positive electrode sheet, the negative electrode sheet and the separator are wound, the film layer is heated, and the heating treatment is at least used to melt the glue points of the glue point group and pre-fix the positive electrode sheet and the separator and / or pre-fix the negative electrode sheet and the separator.

[0015] In some embodiments, while the positive electrode sheet, the negative electrode sheet and the separator are being wound, the process also includes: heating the film layer, wherein the heating process is at least used to melt the glue points of the glue point group and form an adhesive layer.

[0016] According to some embodiments of the present application, on the other hand, the embodiments of the present application further provide an energy storage battery cell, including: a positive electrode sheet, a negative electrode sheet and a separator, the separator is located between the positive electrode sheet and the negative electrode sheet; there is an adhesive layer between the positive electrode sheet and the separator or the negative electrode sheet and the separator, the positive electrode sheet and the separator are fixed by the adhesive layer and / or the negative electrode sheet and the separator are fixed by the adhesive layer; an adhesive group, the adhesive group includes a plurality of the adhesive layers; along the winding direction from the inner circle to the outer circle, the distribution density of the adhesive group decreases.

[0017] The technical solution provided by the embodiments of the present application has at least the following advantages:

[0018] In the technical solution provided in the embodiment of the present application, glue is applied to one of the positive electrode sheet, the diaphragm or the negative electrode sheet, and the glue point group is arranged in a specific manner to alleviate or offset the stress problem caused by the bending area of the core, thereby avoiding the subsequent wrinkling problem at the interface between the positive electrode sheet and the diaphragm and the interface between the diaphragm and the negative electrode sheet caused by the wrinkling of the diaphragm, so as to improve the interface effect. Based on this uneven arrangement, the distribution density of the glue point group decreases as it approaches the first edge, that is, the distribution density is smaller at the position closer to the outer circle of the core, which can ensure that the adhesion of the glue points between the inner circle of the diaphragm and the positive electrode sheet and between the diaphragm and the negative electrode sheet is greater, and then used to resist the stress caused by the bending curvature, so that the positive electrode sheet and the diaphragm, and the diaphragm and the negative electrode sheet are more tightly fitted, improving the problem of easy wrinkling of the inner circle of the core at the full interface, and can reduce the amount of glue used and reduce the preparation cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] One or more embodiments are exemplified by the figures in the corresponding drawings. These exemplified descriptions do not constitute a limitation on the embodiments. Unless otherwise stated, the figures in the drawings do not constitute a scale limitation. In order to more clearly illustrate the embodiments of the present application or the technical solutions in the traditional technology, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 A flow chart of a method for preparing an energy storage cell provided in one embodiment of the present application;

[0021] Figure 2 A preparation flow chart of a method for preparing an energy storage cell according to an embodiment of the present application, wherein the membrane layer is a positive electrode sheet or a negative electrode sheet;

[0022] Figure 3 A preparation flow chart of a membrane layer as a diaphragm in a method for preparing an energy storage cell provided in one embodiment of the present application;

[0023] Figure 4 A top view of a film layer corresponding to the step of providing a film layer in the method for preparing an energy storage cell provided in one embodiment of the present application;

[0024] Figure 5 A first top view of a film layer corresponding to the step of performing a dispensing process in the method for preparing an energy storage battery cell provided in one embodiment of the present application;

[0025] Figure 6 A second top view of the film layer corresponding to the step of performing the dispensing treatment in the method for preparing the energy storage battery cell provided in one embodiment of the present application;

[0026] Figure 7 A third top view of the film layer corresponding to the step of performing the dispensing treatment in the method for preparing the energy storage battery cell provided in one embodiment of the present application;

[0027] Figure 8 A cross-sectional view of an energy storage cell corresponding to a winding step in a method for preparing an energy storage cell provided in an embodiment of the present application. DETAILED DESCRIPTION

[0028] As can be seen from the background technology, the yield of current energy storage cells is poor and the production cost is high.

[0029] Analysis found that one of the reasons for the poor yield and high preparation cost of current energy storage cells is that the main function of conventional diaphragms is to separate the cathode (negative electrode represented by the negative electrode sheet) and anode (positive electrode represented by the positive electrode sheet) materials of the battery to prevent the two electrodes of different polarities from contacting and short-circuiting. In addition, during the electrochemical reaction, it can maintain the necessary electrolyte and form a channel for ion movement.

[0030] To achieve the fixation between the separator and the positive electrode, or the separator and the negative electrode, a rubber coating layer is generally provided on the base film where the separator is located to form a rubber-coated separator. The rubber coating layer is sticky and adheres to the surface of the electrode (positive electrode or negative electrode) after hot pressing, increasing shrinkage resistance and flatness, allowing the electrode and separator to fit tightly, shortening the lithium ion transmission path, and reducing the interfacial impedance between the electrodes. After hot pressing, the rubber coating of the rubber-coated separator solidifies after cooling, improving the mechanical properties of the core composed of the positive electrode, separator, and negative electrode, and facilitating assembly.

[0031] However, the use of glue-coated diaphragms also brings other problems. The diaphragm is completely attached to the surface of the electrode. On the one hand, the surface of the glue-coated diaphragm is completely attached to the surface of the electrode, which increases the amount of glue used and increases the cost of the diaphragm. On the other hand, due to the different curvatures of the bending areas of the inner and outer rings of the winding core, the stress of the inner ring is greater, and the possibility of delamination is greater, which makes the diaphragm of the inner ring prone to wrinkles.

[0032] The present application provides a method for preparing an energy storage battery cell, forming multiple glue point groups and non-uniformly distributed glue points on the film layer, thereby reducing the preparation cost of the glue and improving the problem of easy wrinkling of the inner ring.

[0033] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0034] References to "embodiments" herein mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0035] In the description of the embodiments of this application, the term "and / or" is merely a description of the association relationship between associated objects, indicating that three relationships may exist. For example, A and / or B can represent the following three situations: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0036] 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 groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0037] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do 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 a limitation on the embodiments of the present application.

[0038] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0039] In the accompanying drawings corresponding to the embodiments of the present application, the thickness and area of the layers are exaggerated for better understanding and ease of description. When describing a component (such as a layer, film, region or substrate) on another component or on the surface of another component, the component can be "directly" located on the surface of the other component, or there can be a third component between the two components. On the contrary, when describing a component on the surface of another component or when another component is formed or provided on the surface of a component, it means that there is no third component between the two components. In addition, when describing a component as "approximately" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a partial edge of the entire surface.

[0040] In the description of the embodiments of the present application, when a component "includes" another component, unless otherwise specified, other components are not excluded, and other components may be further included. In addition, when a component such as a layer, film, region, or plate is referred to as being "on / located on" another component, it can be "directly on" the other component (i.e., located on the surface of the other component with no other components between them), or another component may be present therebetween. In addition, when a component such as a layer, film, region, or plate is "directly located on" another component, or when a component such as a layer, film, region, or plate is located on the surface of another component, it means that no other components are located therebetween.

[0041] The terms used in the description of the various embodiments described herein are intended only to describe specific embodiments and are not intended to be limiting. As used in the description of the various embodiments described herein and in the appended claims, "parts" are intended to include the plural form unless the context clearly indicates otherwise. Parts include components such as layers, films, regions, or plates. This improves the yield of the battery cell.

[0042] Figure 1 A flow chart of a method for preparing an energy storage cell provided in one embodiment of the present application.

[0043] According to some embodiments of the present application, the present application provides a method for preparing an energy storage battery cell. Figure 1 The preparation method includes: providing a film layer, the film layer being one of a positive electrode sheet, a separator, or a negative electrode sheet; performing a dispensing process on the film layer to form the other of the positive electrode sheet, the separator, or the negative electrode sheet; and performing a winding process on the positive electrode sheet, the negative electrode sheet, and the separator.

[0044] In which, the film layer has a first edge and a second edge arranged opposite to each other along a first direction; the film layer is subjected to a glue dot treatment so that the surface of the film layer has multiple groups of glue dots arranged along the first direction; the distribution density of the glue dot groups decreases along the direction from the second edge to the first edge; during the winding process, the winding process is performed from the second edge toward the first edge; in which, the diaphragm is located between the positive electrode sheet and the negative electrode sheet, and the winding process is at least used to make the glue dots of the glue dot group molten and form an adhesive layer to fix the positive electrode sheet to the diaphragm and / or the diaphragm to the negative electrode sheet.

[0045] Among them, the first edge is the edge of the outer circle of the core formed by the winding process, and the second edge is the edge of the inner circle of the core; along the direction from the inner circle to the outer circle, the distribution density of the glue point group decreases, so that the adhesion force of the glue points between the inner circle diaphragm and the positive electrode sheet and between the diaphragm and the negative electrode sheet is greater than the adhesion force of the glue points between the outer circle diaphragm and the positive electrode sheet and between the diaphragm and the negative electrode sheet.

[0046] The preparation method of the energy storage battery provided by the present application is to perform glue dispensing on one of the positive electrode sheet, the diaphragm or the negative electrode sheet, and to arrange the glue point group in a specific manner to alleviate or offset the stress problem caused by the bending area of the core, thereby avoiding the problem of wrinkles at the interface between the positive electrode sheet and the diaphragm and the interface between the diaphragm and the negative electrode sheet caused by the subsequent wrinkles of the diaphragm, so as to improve the interface effect. Based on this uneven arrangement method, that is, the distribution density of the glue point group is smaller the closer to the first edge, that is, the distribution density is smaller at the position closer to the outer circle of the core, which can ensure that the adhesion of the glue points between the inner circle diaphragm and the positive electrode sheet and the diaphragm and the negative electrode sheet is greater, and then used to resist the stress caused by the bending curvature, so that the positive electrode sheet and the diaphragm, the diaphragm and the negative electrode sheet are more tightly fitted, improving the problem of easy wrinkles in the inner circle of the core at the full interface, and can reduce the amount of glue used and reduce the preparation cost.

[0047] According to the appearance classification, the prepared energy storage cells can be divided into square cells, round cells or soft-pack cells. According to the capacity classification, the energy storage cells can be divided into 50Ah, 100Ah, 150Ah, 200Ah, 280Ah, 306Ah, 314Ah, 500+Ah, 800+Ah and 1000+Ah models. According to the chemical composition and working principle of the cell, the energy storage cell can be a lithium-ion battery, a lead-acid battery, a sodium-ion battery or a nickel-metal hydride battery. The embodiment of the present application takes the preparation method of a lithium-ion battery as an example. Those skilled in the art can replace the lithium ions in the positive electrode sheet, the negative electrode sheet and the electrolyte with corresponding metal ions according to actual needs. For example, in sodium-ion batteries, the lithium transition metal oxide of the subsequent positive electrode active material is replaced by any of the corresponding layered metal oxides (such as NaFeO2), polyanion compounds (NaFePO4) and Prussian blue compound systems (such as NaMnFe(CN)6-zH2O), and the electrolyte is replaced by any of the organic liquid electrolyte, solid composite electrolyte or solid electrolyte.

[0048] The following detailed description of the various embodiments of the present application is provided in conjunction with the accompanying drawings. However, those skilled in the art will appreciate that many technical details are provided in the various embodiments of the present application to facilitate a better understanding of the present application. However, even without these technical details and the various variations and modifications based on the following embodiments, the technical solutions claimed in the present application can still be implemented.

[0049] In some embodiments, the positive electrode sheet and the negative electrode sheet serve as the positive electrode and negative electrode of the energy storage cell, respectively. The positive electrode is the electrode plate where oxidation reaction occurs in the energy storage cell, and the negative electrode is the electrode plate where reduction reaction occurs in the energy storage cell. The positive electrode and the negative electrode are separated and connected together by an electrolyte. The positive electrode and the negative electrode serve as the electrochemical reaction areas of the energy storage cell.

[0050] The positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer, and the positive electrode active material layer is located on the positive electrode current collector. Part of the positive electrode current collector is cut into the shape of a tab and serves as a positive electrode tab.

[0051] The positive electrode current collector can be aluminum foil, which is cheaper than copper foil. A dense oxide film is formed on the surface of the aluminum foil, and the oxide film is very thin, which can improve the corrosion resistance of the aluminum foil, and electrons can achieve conductivity through the tunnel effect.

[0052] In some embodiments, the positive electrode current collector may also be a composite current collector comprising three stacked layers: an organic middle layer, and upper and lower layers of copper and aluminum. The organic material may be PET (polyethylene terephthalate), PP (polypropylene), or PI (polyimide).

[0053] In some embodiments, the positive electrode current collector may also be a carbon-based current collector, that is, a conductive carbon layer is provided on the aluminum foil. The conductive carbon layer can serve as a protective layer to effectively protect the current collector to prevent corrosion of the metal current collector, thereby increasing the life of the current collector. Secondly, the conductive carbon layer itself has a low resistivity, so that it will not produce excessive electrical losses.

[0054] It should be noted that the carbon-based current collector may be in the form of both the upper and lower surfaces of the aluminum foil being covered with the conductive carbon layer, or may be in the form of a portion of the surface of the aluminum foil being covered with the conductive carbon layer.

[0055] The positive tab is a metal conductor that connects the positive electrode of the energy storage cell to the battery. It serves as the contact point between the positive electrode and the external contact component during charging and discharging. This external contact component can be the terminal.

[0056] The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer, and the negative electrode active material layer is located on the negative electrode current collector. Part of the negative electrode current collector is cut into the shape of a tab and serves as a negative electrode tab.

[0057] In some embodiments, the negative electrode current collector can be copper foil. Copper foil has low electrical conductivity and can have high electron transport capacity. Copper foil also has weak lithium insertion capacity and captures fewer lithium ions, thereby effectively reducing lithium ion loss. In other embodiments, the negative electrode current collector can also be a foam copper current collector, a copper mesh current collector, or a three-dimensional nano-copper array current collector.

[0058] In some embodiments, the negative electrode active material layer may be composed of a negative electrode active material, a conductive agent, and a binder. The negative electrode active material may be classified into two categories: carbon materials and non-carbon materials. Carbon-based materials include graphite materials (natural graphite, artificial graphite, and mesophase carbon spheres) and other carbon-based materials (hard carbon, soft carbon, and graphene). Non-carbon-based materials can be further divided into titanium-based materials, silicon-based materials, tin-based materials, nitrides, and metallic lithium.

[0059] The conductive agent is similar to that of the positive electrode active material layer, and the adhesive for the negative electrode is similar to that for the positive electrode, mainly including oil-based PVDF (polyvinylidene fluoride), water-based CMC (carboxymethyl cellulose), PVA (polyvinyl alcohol), sodium alginate, etc., which will not be repeated here.

[0060] The negative electrode tab is a metal conductor that connects the negative electrode of the energy storage cell to the battery. It serves as the point of contact between the negative electrode and the external contact component during charging and discharging. This external contact component can be a terminal.

[0061] The separator is used to prevent short circuit problems caused by physical contact between the positive electrode and the negative electrode, while allowing ions to conduct through the electrolyte and hindering the transmission of electrons, so that ions and electrons form a circuit during the charging and discharging process of the battery.

[0062] The diaphragm can be any of a microporous membrane, a modified microporous membrane, a non-woven membrane, and a composite membrane. A microporous membrane is a membrane with a pore size in the micrometer range, mainly including polyolefin microporous membranes and other polymer microporous membranes. A modified microporous membrane is a membrane obtained by modifying a microporous membrane. Common modification methods include surface treatment, chemical grafting, surface coating, etc. Non-woven membranes have a small fiber diameter and generally exhibit a higher porosity than other types of membranes. Composite membranes are prepared by coating or filling inorganic materials into microporous membranes or non-woven membranes. Compared with other types of membranes, they have higher thermal stability and electrolyte wettability.

[0063] Figure 2 A preparation flow chart of a method for preparing an energy storage cell according to an embodiment of the present application, wherein the membrane layer is a positive electrode sheet or a negative electrode sheet; Figure 3 A preparation flow chart of a diaphragm membrane in a method for preparing an energy storage cell provided in one embodiment of the present application.

[0064] refer to Figure 2, the film layer is a positive electrode sheet or a negative electrode sheet, and before the dispensing process is performed, it also includes: die-cutting the positive electrode sheet or the negative electrode sheet to form a tab adjacent to the first edge. In this way, dispensing the glue on the positive electrode sheet / negative electrode sheet can avoid the situation where large areas of wrinkles appear around the glue-coated area due to the soft texture of the diaphragm, and even the problem of "dead wrinkles" formed during the subsequent cold pressing process. In other words, dispensing the glue on the positive electrode sheet / negative electrode sheet can effectively avoid the wrinkle problem caused by the dispensing of the diaphragm, thereby avoiding the subsequent wrinkle problem at the interface between the positive electrode sheet and the diaphragm and the interface between the diaphragm and the negative electrode sheet caused by the wrinkles of the diaphragm, so as to improve the interface effect. The tab can be the positive electrode tab of the positive electrode sheet or the negative electrode tab of the negative electrode sheet.

[0065] In some embodiments, after the conventional positive and negative electrodes are coated with the active material layer, they are cut into corresponding positive and negative electrodes, and then the formed positive and negative electrodes are subjected to a die-cutting process based on certain die-cutting parameters. The die-cutting process includes the steps of die-cutting loading, unwinding, tab die-cutting, and winding and unloading. The preparation method provided in the embodiment disclosed in the present application performs a dispensing process after the tab die-cutting, that is, the first edge and the second edge are distinguished based on the position of the tab, and then the inner ring and the outer ring are distinguished during the subsequent winding process. Compared with other distinguishing processes and distinguishing methods, it is more convenient and quick. In addition, improvements based on the original process will not have a significant impact on the original equipment and steps, thereby reducing the preparation cost.

[0066] refer to Figure 3 The membrane layer is a diaphragm, and the process steps of performing glue dispensing treatment, forming positive and negative electrode sheets and performing winding treatment include: providing a diaphragm, a positive electrode sheet, and a negative electrode sheet; loading the diaphragm, the positive electrode sheet, and the negative electrode sheet in sequence; performing glue dispensing treatment on the diaphragm; and performing winding treatment on the positive electrode sheet, the negative electrode sheet, and the diaphragm.

[0067] In some embodiments, after the conventional positive and negative electrodes are coated with the active material layer, they are cut into corresponding positive and negative electrodes, and then the formed positive and negative electrodes are subjected to a die-cutting process based on certain die-cutting parameters, and finally a winding process is performed. The die-cutting process includes the steps of die-cutting loading, unwinding, tab die-cutting, and winding and unloading. The winding process includes the steps of winding loading, unwinding, winding processing, and unloading. The preparation method provided in the embodiment disclosed in the present application performs a dispensing process on the diaphragm after unwinding. That is to say, the diaphragm, the positive electrode sheet, and the negative electrode sheet are aligned at this time. In this way, the first edge and the second edge can be distinguished based on the position of the tab, and then the inner ring and the outer ring during the subsequent winding process can be distinguished. Compared with other distinguishing processes and distinguishing methods, it is more convenient and quick.

[0068] The following will describe the distribution arrangement in the dispensing process provided by the embodiment of the present application in conjunction with the relevant drawings.

[0069] Figure 4 A top view of a film layer corresponding to a film layer provided in a method for preparing an energy storage cell provided in one embodiment of the present application; Figure 5 A first top view of a film layer corresponding to the dispensing process in the method for preparing an energy storage battery cell provided in one embodiment of the present application; Figure 6 A second top view of a film layer corresponding to the dispensing process in the method for preparing an energy storage battery cell provided in one embodiment of the present application; Figure 7 A third top view of a film layer corresponding to the dispensing process in the method for preparing an energy storage cell provided in one embodiment of the present application.

[0070] refer to Figure 4 The preparation method includes: providing a film layer 10, the film layer 10 is one of a positive electrode sheet, a separator or a negative electrode sheet, and the film layer 10 has a first edge 101 and a second edge 102 arranged opposite to each other along a first direction X.

[0071] In some embodiments, if the film layer 10 is a positive electrode sheet or a negative electrode sheet, the end near the first edge 101 has a tab, that is, the positive electrode sheet / negative electrode sheet after the die-cutting step, and the first edge 101 and the second edge 102 are distinguished by the position of the tab.

[0072] refer to Figure 5 or Figure 6 The preparation method includes: applying glue to the film layer 10 so that the surface of the film layer 10 has multiple groups of glue dots arranged along a first direction X; the distribution density of the glue dots within the glue dot groups decreases along the direction from the second edge 102 to the first edge 101. The glue dot groups are composed of multiple glue dots arranged at intervals along the second direction.

[0073] In some embodiments, the size of the glue dot is d0, and d0 is between 0.1mm and 0.5mm. The size of the glue dot can be any range of 0.1mm to 0.2mm, 0.2mm to 0.3mm, 0.3mm to 0.4mm, or 0.4mm to 0.5mm. The size of the glue dot can be 0.1mm, 0.18mm, 0.23mm, 0.38mm, 0.46mm, or 0.5mm. The size range of the glue dot can make the distribution density of the glue dot group easier to plan, thereby reducing the difficulty of preparing the glue dot. The size range of the glue dot can also avoid the glue dot being too large, and the stress caused by subsequent curing will have a negative impact on the film layer, thereby improving the yield of the energy storage battery cell.

[0074] In some embodiments, the distance between two adjacent glue dots is L0, and L0 is between 1d0 and 2d0. L0 can be any range of 1d0 to 1.2d0, 1.2d0 to 1.5d0, 1.5d0 to 1.8d0, or 1.8d0 to 2d0. L0 can be 1d0, 1.3d0, 1.6d0, or 1.9d0.

[0075] In some embodiments, the spacing between two adjacent groups of glue dots is S0, and S0 is between 1.2d0 and 2.5d0. S0 can be any range of 1.2d0 to 1.5d0, 1.5d0 to 1.8d0, 1.8d0 to 2.1d0, or 2.1d0 to 2.5d0. S0 can be 1.3d0, 1.6d0, 1.9d0, 2.3d0, or 2.5d0.

[0076] In some embodiments, the ratio of the total area of the orthographic projections of the glue dots in the plurality of glue dot groups on the film layer 10 to the surface area of the film layer 10 is 10% to 14%. The ratio of the total area of the orthographic projections of the glue dot groups on the film layer 10 to the surface area of the film layer 10 can be 10%, 11%, 12%, 13%, or 14%. Thus, the ratio of the total area of the orthographic projections of the glue dot groups on the film layer 10 to the surface area of the film layer 10 can be understood as the area where the glue dots are formed within a front film layer. If the total area of the glue dots and the surface area of the film layer are within the above range, the content of the glue dots is relatively appropriate, thereby achieving mutual adhesion between the positive electrode sheet and the separator, and mutual adhesion between the negative electrode sheet and the separator, and preventing separation between the two. Secondly, the content of glue is also relatively appropriate, thereby reducing the cost of glue preparation and avoiding glue overflow.

[0077] In some embodiments, the area from the middle of the film along the first direction to the first edge is a sparse area, and the area from the boundary to the second edge is a dense area. In the dense area, the glue dots have a size of D1 ranging from 1d0 to 1.2d0, a spacing of S1 between two adjacent groups of glue dots, which is 0.9S0, and a spacing of C1 between two adjacent glue dots, which is 0.9L0. The total area of the glue dots accounts for 12% to 16% of the film area. In the sparse area, the glue dots have a size of D2 ranging from 0.8d0 to 1d0, a spacing of S2 between two adjacent groups of glue dots, which is 1.1S0, and a spacing of C2 between two adjacent glue dots, which is 1.3L0. The total area of the glue dots accounts for 7% to 11% of the film area.

[0078] It should be noted that the spacing refers to the straight-line distance between the center of a glue dot and the center of another glue dot, and the size of a glue dot refers to any value between the minimum distance and the maximum distance of the glue dots.

[0079] In some embodiments, the glue points of each glue point group are sequentially formed by interpolation, which may be a linear interpolation model or a Lagrangian interpolation model.

[0080] In some embodiments, reference Figure 5 , the first glue dot group 120 near the first edge 101 and the second glue dot group 130 near the second edge 102, the first spacing L1 between adjacent first glue dots 121 in the first glue dot group 120 is greater than the second spacing L2 between adjacent second glue dots 131 in the second glue dot group 130. The difference in spacing between glue dot groups at different positions also results in different distribution densities of glue dots per unit area, that is, the distribution density of first glue dots 121 in the first glue dot group 120 near the first edge 101 is less than the distribution density of second glue dots 131 in the second glue dot group 130 near the second edge 102, that is, the distribution density of glue dots near the inner circle is greater, thereby having a greater adhesive force to avoid and resist the stress caused by the winding process, thereby preventing delamination between the inner circle separator and the positive electrode sheet / the separator and the negative electrode sheet, and thus preventing separator wrinkles.

[0081] In addition, if the spacing is large, the area where the outer ring is located can be used as a channel for gas discharge, that is, when the outer ring diaphragm, positive electrode plate and negative electrode plate release the gas due to the electrolyte, it can be discharged through the channel formed by the two glue points, thereby avoiding the problem of bubbles formed by the gas and causing wrinkles in the diaphragm.

[0082] In some embodiments, the ratio of the first spacing L1 to the second spacing L2 is 1.03 to 1.3. The ratio of the first spacing to the second spacing can be 1.03, 1.1, 1.2, or 2. Thus, by controlling the relevant parameters of the dispensing process within this range, the manufacturing cost can be reduced while ensuring good adhesion between the separator and the positive electrode sheet, thereby improving the corresponding problem.

[0083] In some embodiments, reference Figure 6 The glue dot group includes: a first glue dot group 120 near the first edge 101 and a second glue dot group 130 near the second edge 102. The size d1 of the first glue dot 121 in the first glue dot group 120 is smaller than the size d2 of the second glue dot 131 in the second glue dot group 130. As such, the distribution density of the first glue dot group 120 near the first edge 101 is smaller than the distribution density of the second glue dot group 130 near the second edge 102. That is, the glue dot distribution density near the inner circle is higher, resulting in greater adhesion to prevent and resist stress caused by the winding process. This prevents delamination between the inner circle separator and the positive electrode sheet, or between the separator and the negative electrode sheet, and thus prevents separator wrinkles.

[0084] in, Figure 5The size of each glue dot shown can be the same, that is, the original size d. In some embodiments, the sizes of the glue dots can also be different, but the distribution density of the glue dot group near the first edge 101 must be less than the distribution density of the glue dot group near the second edge 102. For example, the size of the first glue dot 121 is smaller than the size of the second glue dot 131. Similarly, Figure 6 The spacing between each adjacent glue dot shown can be the same, that is, the original spacing L. In some embodiments, the spacing between adjacent glue dots can also be different, but the distribution density of the glue dot group near the first edge 101 must be less than the distribution density of the glue dot group near the second edge 102. For example, the glue dot spacing in the first glue dot group 120 is greater than the glue dot spacing in the second glue dot group 130.

[0085] It should be noted that Figures 5 to 7 The shape of the glue dots is circular as an example, but this does not constitute a limitation on the shape and size of the glue dots. Those skilled in the art can design the shape and size of the glue dots as needed to ensure that the distribution density near the first edge 101 is less than the distribution density near the second edge 102.

[0086] In some embodiments, the film layer 10 further has two third edges 103 arranged opposite each other along the second direction Y. Each end of each third edge 103 is connected to the first edge 101 and the second edge 102, respectively. During the glue dispensing process on the film layer 10, the density of glue dots within the glue dot group near the third edge 103 is the highest, moving from the center of the film layer in the second direction toward the third edge. This high density of glue dots on both sides ensures a tighter fit between the edge separator and the positive / negative electrode sheet, reduces damage to the friction layer on the side during subsequent core transport, and mitigates impact of airflow and electrolyte on the core during the injection and formation process. It also addresses the problem of brown spots that often appear at the bottom of the core head at the fully filled interface. It also reduces glue usage and lowers manufacturing costs.

[0087] In some embodiments, along the second direction Y and pointing to the third edge 103, the spacing between adjacent glue dots decreases; and / or, referring to Figure 7 Along the second direction toward the third edge 103, the size of the glue dots increases. For example, the size d21 of the glue dots closer to the third edge is larger than the size d20 of the glue dots farther from the third edge. Both the decreasing spacing between the glue dots and the increasing size of the glue dots can cause the distribution density to increase along the second direction toward the third edge 103. This results in a higher content of glue near the edge, which in turn allows for a closer fit between the edge of the diaphragm and the electrode.

[0088] It should be noted that Figure 7Only the second glue dot in the second glue dot group 130 is shown to show a trend of increasing glue dot size along the second direction and pointing to the third edge 103, but the first glue dot in the first glue dot group 120 and the glue dot groups in the first glue dot group 120 and the second glue dot group 130 may also show this trend, and the embodiments of the present application do not limit this description.

[0089] In some embodiments, the film layer 10 is heated before the positive electrode sheet, negative electrode sheet, and separator are wound. The heating process is used to melt the adhesive points of the adhesive point group and pre-fix the positive electrode sheet and separator and / or pre-fix the negative electrode sheet and separator. In this way, the adhesive points on the film layer are activated and become sticky after heating. During the fixing process, the battery cell to be formed is pre-heated and pressed. The pre-heated and pressed adhesive becomes activated and sticky, thereby adhering and fixing the positive electrode sheet / negative electrode sheet and separator.

[0090] In some embodiments, the winding process of the positive electrode sheet, negative electrode sheet, and separator also includes heating the film layer 10. The heating process is used to at least melt the adhesive points of the adhesive point group and form an adhesive layer. Heating during winding, also known as hot winding, can activate the adhesive points on the film layer, improve the subsequent cold pressing process and core forming, and enhance the interface between the separator and the positive electrode sheet.

[0091] refer to Figure 8 The preparation method includes: performing a winding process on a positive electrode sheet 1, a negative electrode sheet 2, and a separator 3. During the winding process, the winding process is performed from the second edge 102 toward the first edge 101. The separator is located between the positive electrode sheet and the negative electrode sheet. The winding process is at least used to melt the glue points of the glue point group and form an adhesive layer to fix the positive electrode sheet to the separator or the separator to the negative electrode sheet.

[0092] In some embodiments, the winding process involves winding the separator 3, the positive electrode sheet 1, and the negative electrode sheet 2 into a single core through a winding machine. The order is to wrap the positive electrode sheet 1 with the negative electrode sheet 2, and then separate the positive electrode sheet 1 and the negative electrode sheet 2 with the separator 3.

[0093] In some embodiments, low winding tension will affect the internal resistance and shell penetration rate; excessive tension can easily cause short circuit or breakage risks. Therefore, the winding tension is generally between 0.08Mpa and 0.15Mpa for positive tension, 0.08Mpa and 0.15Mpa for negative tension, 0.08Mpa and 0.15Mpa for upper diaphragm tension, and 0.08Mpa and 0.15Mpa for lower diaphragm tension. The width of the negative electrode sheet 2, the width of the positive electrode sheet 1, and the width of the diaphragm 3 are not the same. For example, the width of the negative electrode sheet is 59.5mm, the width of the positive electrode sheet is 58mm, and the width of the diaphragm is 61mm. The three are aligned in the center to improve the alignment of the electrode sheets and avoid the risk of short circuit. The electrode sheet alignment refers to the relative positions of the positive electrode sheet 1, the negative electrode sheet 2, and the diaphragm 3.

[0094] In some embodiments, the process steps of the winding treatment include: hot winding treatment and cold pressing treatment. The hot winding treatment is used to make the glue points of the glue point group molten and form an adhesive layer to fix the positive electrode sheet and the diaphragm and / or the diaphragm and the negative electrode sheet; the cold pressing treatment is used to fit the positive electrode sheet, the negative electrode sheet and the diaphragm together.

[0095] It should be noted that in order to explain and distinguish the diaphragm, positive electrode sheet and negative electrode sheet, Figure 8 The dotted line indicates the separator, the thinner solid line indicates the negative electrode, and the thicker solid line indicates the positive electrode, but this does not represent the thickness relationship between the separator, the positive electrode, and the negative electrode. Figure 8 There is a gap between the middle separator 3, the positive electrode sheet 1 and the negative electrode sheet 2. This is to clearly indicate the winding correspondence between the separator 3, the positive electrode sheet 1 and the negative electrode sheet 2, but it does not mean that there must be a gap between the separator 3 and the positive electrode sheet 1 or the separator 3 and the negative electrode sheet 2. In other words, the separator 3 and the positive electrode sheet 1 can be in contact with each other, or the separator 3 and the negative electrode sheet 2 can be in contact with each other.

[0096] The method for preparing the energy storage cell further includes: placing the whole body formed by winding the positive electrode sheet 1, the negative electrode sheet 2 and the separator 3 in a cavity formed by the shell, and the cavity is also filled with electrolyte.

[0097] The electrolyte is a carrier that conducts electrons between the positive and negative electrodes in the battery. In some embodiments, the electrolyte can be an electrolyte solution, which is composed of three parts: a solvent, a lithium salt, and an additive. The solvent is used to dissolve the lithium salt, and the solvent can include cyclic carbonates (PC, EC); chain carbonates (DEC, DMC, EMC); carboxylates (MF, MA, EA, MA, MP, etc.). The lithium salt can be LiPF6, LiClO4, LiBF4, LiAsF6, etc. The additive can be one or more of a film-forming additive, a conductive additive, a flame retardant additive, an overcharge protection additive, an additive for controlling the content of H2O and HF in the electrolyte, an additive for improving low-temperature performance, and a multifunctional additive.

[0098] The preparation method includes: welding the tab, welding the tab to the adapter, connecting the other end of the adapter to the pole, and engaging the top rod with the shell. The adapter is located in the chamber and the pole passes through the top cover.

[0099] Among them, the adapter plate includes at least a first adapter plate and a second adapter plate, the pole includes a positive pole pole and a negative pole pole, the first adapter plate is electrically connected to the pole ear of the positive pole plate and the positive pole pole respectively, and the second adapter plate is electrically connected to the negative pole ear of the negative pole plate and the negative pole pole respectively.

[0100] The preparation method of the energy storage battery provided by the present application is to perform glue dispensing on one of the positive electrode sheet 1, the diaphragm 3 or the negative electrode sheet 2, and arrange the glue point group in a specific manner to alleviate and offset the stress problem caused by the bending area of the core, thereby avoiding the problem of wrinkles at the interface between the positive electrode sheet and the diaphragm and the interface between the diaphragm and the negative electrode sheet caused by the subsequent wrinkles of the diaphragm, so as to improve the interface effect. Based on this uneven arrangement method, that is, the distribution density of the glue point group is smaller the closer to the first edge 101, that is, the distribution density is smaller at the position closer to the outer circle of the core, which can ensure that the adhesion of the glue points between the inner circle diaphragm and the positive electrode sheet and the diaphragm and the negative electrode sheet is greater, and then used to resist the stress caused by the bending curvature, so that the positive electrode sheet and the diaphragm, the diaphragm and the negative electrode sheet are more tightly fitted, improving the problem of easy wrinkles in the inner circle of the core at the full interface, and can reduce the amount of glue used and reduce the preparation cost.

[0101] Accordingly, according to some embodiments of the present application, the embodiments of the present application further provide an energy storage battery cell, which can be prepared using the preparation method provided in the above embodiments. The technical features that are the same as or corresponding to the above embodiments will not be described in detail here.

[0102] refer to Figure 8 and Figure 7 The energy storage cell includes: a positive electrode sheet 1, a negative electrode sheet 2 and a separator 3, the separator 3 is located between the positive electrode sheet 1 and the negative electrode sheet 2; there is an adhesive layer 140 between the positive electrode sheet 1 and the separator 3 or the negative electrode sheet 2 and the separator 3, the positive electrode sheet 1 and the separator 3 are fixed by the adhesive layer 140 and / or the negative electrode sheet 2 and the separator 3 are fixed by the adhesive layer 140; the adhesive group includes multiple adhesive layers 140; along the winding direction from the inner circle to the outer circle, the distribution density of the adhesive group decreases.

[0103] Among them, the inner circle refers to the inner circle of the formed core structure, corresponding to Figure 6 The outer ring refers to the outer ring of the core structure formed, corresponding to Figure 6 The first edge in .

[0104] Along the winding direction from the inner circle to the outer circle, the distribution density of the viscose group decreases, so that the adhesion force of the viscose layer between the inner circle diaphragm and the positive electrode sheet and between the diaphragm and the negative electrode sheet is greater than the adhesion force of the viscose layer between the outer circle diaphragm and the positive electrode sheet and between the diaphragm and the negative electrode sheet.

[0105] In some embodiments, the adhesive layer is formed by solidifying molten adhesive dots, and the initial size of the adhesive dots is 0.1 mm to 0.5 mm.

[0106] In some embodiments, the adhesive group includes a first adhesive group close to the inner circle and a second adhesive group close to the outer circle, and the spacing between adhesive layers in the first adhesive group is 1.03 to 1.3 times the spacing between adhesive layers in the second adhesive group.

[0107] In some embodiments, the total orthographic projection area of the adhesive layer on the separator, the positive electrode sheet, or the negative electrode sheet accounts for 10% to 14% of the surface area of the corresponding film layer.

[0108] The energy storage cell provided in the embodiment of the present application has an unevenly distributed glue, and the positive electrode sheet or negative electrode sheet corresponding to the outer ring and the diaphragm are not completely adhered, so that there is a microscopic channel between the positive electrode sheet / negative electrode sheet or the positive electrode sheet and the positive electrode sheet, and the electrolyte can flow directly to the adhered area in the middle of the electrode sheet, so that not only the edge penetrates into the middle area by capillary action, which reduces the difficulty of cell infiltration, thereby improving the yield of the energy storage cell. Moreover, this channel can also serve as a gas accommodating area, so that the gas generated by charging and discharging of the battery cell stays in the gas accommodating area, which can reduce the impact of the gas on the diaphragm and prevent the diaphragm from separating from the electrode sheet. The gas accommodating area can also serve as a buffer zone to facilitate gas seepage, especially when the battery cell is not working, the gas continues to seep out of the gas accommodating area to achieve the emptying of the gas accommodating area, so that after the battery cell generates gas through charging and discharging, the gas will gather in the gas accommodating area again.

[0109] Those skilled in the art will appreciate that the above-described embodiments are specific examples for implementing the present application, and that in actual applications, various changes in form and detail may be made thereto without departing from the spirit and scope of the present application. Any person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present application. Therefore, the scope of protection of the present application shall be based on the scope defined in the claims.

Claims

1. A method for preparing an energy storage battery cell, characterized in that: include: Providing a film layer, wherein the film layer is one of a positive electrode sheet, a separator, or a negative electrode sheet, and the film layer has a first edge and a second edge disposed opposite to each other along a first direction; Performing a glue dispensing process on the film layer so that a surface of the film layer has a plurality of glue dot groups arranged along a first direction; and the distribution density of the glue dot groups decreases along a direction from the second edge to the first edge; forming the positive electrode sheet, the separator, or the other two of the negative electrode sheet; The positive electrode sheet, the negative electrode sheet, and the separator are subjected to a winding process, the winding process being performed from the second edge toward the first edge; wherein the separator is located between the positive electrode sheet and the negative electrode sheet, and the winding process is at least used to melt the glue points of the glue point group and form an adhesive layer to fix the positive electrode sheet to the separator and / or to fix the separator to the negative electrode sheet; Among them, the first edge is the edge of the outer circle of the core formed by the winding process, and the second edge is the edge of the inner circle of the core; along the direction from the inner circle to the outer circle, the distribution density of the glue point group decreases, so that the adhesion force of the glue points between the diaphragm of the inner circle and the positive electrode sheet and between the diaphragm and the negative electrode sheet is greater than the adhesion force of the glue points between the diaphragm of the outer circle and the positive electrode sheet and between the diaphragm and the negative electrode sheet.

2. The method for preparing the energy storage battery cell according to claim 1, wherein: The film layer also has two third edges arranged opposite to each other along the second direction, and the two ends of each third edge are respectively connected to the first edge and the second edge; during the process of dispensing glue on the film layer, the distribution density of the glue points within the same glue point group increases from the center of the film layer in the second direction toward the third edge.

3. The method for preparing the energy storage battery cell according to claim 2, wherein: Along the second direction and pointing to the third edge, the distance between adjacent glue dots in the same glue dot group decreases; and / or, along the second direction and pointing to the third edge, the size of the glue dots in the same glue dot group increases.

4. The method for preparing the energy storage battery cell according to claim 1, wherein: The glue dot group includes: a first glue dot group close to the first edge and a second glue dot group close to the second edge, the size of the first glue dot in the first glue dot group is smaller than the size of the second glue dot in the second glue dot group; and / or, the first spacing between adjacent first glue dots in the first glue dot group is greater than the second spacing between adjacent second glue dots in the second glue dot group.

5. The method for preparing the energy storage battery cell according to claim 4, characterized in that: The ratio of the first spacing to the second spacing is 1.03 to 1.

3.

6. The method for preparing the energy storage battery cell according to claim 1, characterized in that: The proportion of the total area of the orthographic projections of the plurality of glue point groups on the film layer to the surface area of the film layer is 10% to 14%.

7. The method for preparing an energy storage battery cell according to claim 1, wherein: The process steps of the winding treatment include: hot winding treatment and cold pressing treatment. The hot winding treatment is used to make the glue points of the glue point group present in a molten state and form the adhesive layer to fix the positive electrode sheet and the diaphragm and / or to fix the diaphragm and the negative electrode sheet; the cold pressing treatment is used to make the positive electrode sheet, the negative electrode sheet and the diaphragm fit together.

8. The method for preparing an energy storage battery cell according to claim 1, wherein: Before winding the positive electrode sheet, the negative electrode sheet and the separator, the film layer is subjected to a heat treatment, and the heat treatment is at least used to melt the glue points of the glue point group and pre-fix the positive electrode sheet and the separator and / or pre-fix the negative electrode sheet and the separator.

9. The method for preparing an energy storage battery cell according to claim 1, wherein: While the positive electrode sheet, the negative electrode sheet and the separator are being wound, the method further comprises: heating the film layer, wherein the heating treatment is at least used to melt the glue points of the glue point group and form the adhesive layer.

10. An energy storage battery cell, characterized in that: include: A positive electrode sheet, a negative electrode sheet, and a separator, wherein the separator is located between the positive electrode sheet and the negative electrode sheet; an adhesive layer is provided between the positive electrode sheet and the separator or between the negative electrode sheet and the separator, and the positive electrode sheet and the separator are fixed to each other via the adhesive layer and / or the negative electrode sheet and the separator are fixed to each other via the adhesive layer; an adhesive group, the adhesive group comprising a plurality of adhesive layers; Along the winding direction from the inner ring to the outer ring, the distribution density of the adhesive group decreases, so that the adhesion force of the adhesive layer between the inner ring diaphragm and the positive electrode sheet and between the diaphragm and the negative electrode sheet is greater than the adhesion force of the adhesive layer between the outer ring diaphragm and the positive electrode sheet and between the diaphragm and the negative electrode sheet.

11. The energy storage cell according to claim 10, characterized in that: The adhesive layer is formed by solidifying molten adhesive dots, and the initial size of the adhesive dots is 0.1 mm to 0.5 mm.

12. The energy storage cell according to claim 10, characterized in that: The viscose group includes a first viscose group close to the inner ring and a second viscose group close to the outer ring. The spacing between viscose layers in the first viscose group is 1.03 to 1.3 times the spacing between viscose layers in the second viscose group.

13. The energy storage cell according to claim 10, characterized in that: The total orthographic projection area of the adhesive layer on the separator, the positive electrode sheet or the negative electrode sheet accounts for 10% to 14% of the surface area of the corresponding film layer.

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