Energy storage battery cell and its preparation method

Abstract

Embodiments of the present application relate to the field of energy storage, and provide an energy storage cell and a preparation method thereof. The preparation method includes: providing a film layer, which 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; performing dotting treatment on the film layer so that the surface of the film layer has multiple groups of glue dot groups arranged in a first direction; along the direction from the second edge to the first edge, the distribution density of the glue dot groups decreases; forming the other two of the positive electrode sheet, the separator, or the negative electrode sheet; performing winding treatment on the positive electrode sheet, the negative electrode sheet, and the separator, and winding from the second edge towards the first edge; wherein, the separator is located between the positive electrode sheet and the negative electrode sheet, and the winding treatment is at least used for the glue dots of the glue dot groups to present a molten state and form an adhesive layer, so that the positive electrode sheet is fixed to the separator or the separator is fixed to the negative electrode sheet. The energy storage cell and the preparation method provided by the embodiments of the present application can at least improve the yield of the energy storage cell and reduce the preparation cost.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of energy storage, and particularly to an energy storage cell and a preparation method thereof. Background Art

[0002] In recent years, lithium-ion batteries have received 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. Their development has advanced by leaps and bounds, with the market share continuously expanding and occupying a dominant position.

[0003] The development focus in the preparation process of lithium-ion batteries lies in the cycle stability, preparation cost, and yield of the cells, etc. Currently, there are mainly two ways to improve the energy density of the cells. One is the stacking type, and the other is the winding type. Among them, the winding type is the most common way to improve the energy density. In the cross-section of a wound cell, the wound cell includes two parts, one is a flat extension area, and the other is a curved bending area. The wound core is formed by winding multiple layers of thin film materials. Tension will be generated during winding. When the tension is inappropriate, problems such as bending, wrinkling, and even breaking will occur. These defects increase the safety risk of the battery, especially in the bending area corresponding to the curvature, where the separator is more likely to wrinkle. One of the current improvement measures is to release the stress of the separator before preparing the lithium battery. This method has a high cost and will cause environmental pollution. Another current improvement measure is to change the crystal region and amorphous region structure of the separator to improve the anti-wrinkle ability of the separator. However, there may be problems of introducing other side effects, such as causing excessive self-discharge of the lithium battery, or the high-modulus separator may cause the lithium battery cell to be more likely to deform in an "S" shape during the cyclic use process, etc.

[0004] Therefore, there is an urgent need for a preparation method of an energy storage cell that can fix the separator, 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

[0005] The embodiments of the present application provide an energy storage cell and a preparation method thereof, which are at least beneficial to improving the yield of the energy storage cell and reducing the preparation cost.

[0006] According to some embodiments of the present application, on the one hand, an embodiment of the present application provides a method for preparing an energy storage battery cell, including: providing a film layer, where 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 that are oppositely arranged along a first direction; performing dotting treatment on the film layer so that the surface of the film layer has multiple groups of glue dot groups arranged along the first direction; along the direction from the second edge to the first edge, the distribution density of the glue dot groups decreases; forming the other two of the positive electrode sheet, the separator, or the negative electrode sheet; performing winding treatment on the positive electrode sheet, the negative electrode sheet, and the separator, and performing the winding treatment from the second edge towards the first edge; where the separator 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 groups present in a molten state and form an adhesive layer, so that the positive electrode sheet is fixed to the separator and / or the separator is fixed to the negative electrode sheet.

[0007] In some embodiments, the film layer further has two third edges that are oppositely arranged along a second direction, and both ends of each third edge are respectively connected to the first edge and the second edge; during the dotting treatment of the film layer, in the direction from the center of the film layer in the second direction towards the third edge, within the same glue dot group, the distribution density within the glue dot group increases.

[0008] In some embodiments, along the second direction and towards the direction of the third edge, the distance between adjacent glue dots within the same glue dot group decreases; and / or, along the second direction and towards the direction of the third edge, the size of the glue dots within the same glue dot group increases.

[0009] In some embodiments, the glue dot groups include: a first glue dot group close to the first edge and a second glue dot group close to the second edge, and the size of the first glue dots in the first glue dot group is smaller than the size of the second glue dots in the second glue dot group; and / or, the first distance between adjacent first glue dots in the first glue dot group is greater than the second distance between adjacent second glue dots in the second glue dot group.

[0010] In some embodiments, the ratio of the first distance to the second distance is 1.03 to 1.3.

[0011] In some embodiments, the proportion of the total area of the positive projections of multiple groups of the glue dot groups on the film layer in the surface area of the film layer is 10% to 14%.

[0012] In some embodiments, the process steps of the winding process include: a hot winding process and a cold pressing process. The hot winding process is used to make the glue dots of the glue dot group present in a molten state and form an adhesive layer, so as to fix the positive electrode sheet to the separator and / or fix the separator to the negative electrode sheet; the cold pressing process is used to bond the positive electrode sheet, the negative electrode sheet and the separator to each other in pairs.

[0013] In some embodiments, before winding the positive electrode sheet, the negative electrode sheet and the separator, the film layer is heated. The heating process is at least used to make the glue dots of the glue dot group present in a molten state and pre-fix the positive electrode sheet to the separator and / or pre-fix the negative electrode sheet to the separator.

[0014] In some embodiments, while winding the positive electrode sheet, the negative electrode sheet and the separator, it further includes: heating the film layer. The heating process is at least used to make the glue dots of the glue dot group present in a molten state and form an adhesive layer.

[0015] According to some embodiments of the present application, on the other hand, an energy storage cell provided by the embodiments of the present application includes: a positive electrode sheet, a negative electrode sheet and a separator, and 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 between the negative electrode sheet and the separator, and the positive electrode sheet and the separator are fixed through the adhesive layer and / or the negative electrode sheet and the separator are fixed through 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.

[0016] The technical solutions provided by the embodiments of the present application have at least the following advantages:

[0017] In the technical solutions provided by the embodiments of the present application, dot glue treatment is performed on one of the positive electrode sheet, the separator or the negative electrode sheet, and the glue dot group is arranged in a specific manner to relieve or offset the stress problem caused by the bending area of the winding core, so as to avoid the problem of wrinkles at the interface between the positive electrode sheet and the separator and the interface between the separator and the negative electrode sheet caused by subsequent separator wrinkles, so as to improve the interface effect. Based on this non-uniform arrangement method, the distribution density of the glue dot group is smaller closer to the first edge, that is, the distribution density is smaller at the position closer to the outer circle of the winding core, which can ensure that the adhesion of the glue dots between the separator and the positive electrode sheet and between the separator and the negative electrode sheet in the inner circle is greater, and then used to resist the stress caused by the bending arc, so that the positive electrode sheet and the separator, and the separator and the negative electrode sheet are more closely attached, improving the problem that the inner circle of the winding core at the full charge interface is prone to wrinkles, and can reduce the amount of glue used and reduce the preparation cost. Description of the Drawings

[0018] One or more embodiments are exemplarily illustrated by the figures in the corresponding drawings. These exemplary illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the figures in the drawings do not constitute a scale limitation. To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0019] Figure 1 It is a flowchart of a preparation method of a energy storage battery cell provided by an embodiment of the present application.

[0020] Figure 2 It is a preparation flowchart of a membrane layer as a positive electrode sheet or a negative electrode sheet in the preparation method of a energy storage battery cell provided by an embodiment of the present application.

[0021] Figure 3 It is a preparation flowchart of a membrane layer as a separator in the preparation method of a energy storage battery cell provided by an embodiment of the present application.

[0022] Figure 4 It is a top view of the membrane layer corresponding to the step of providing the membrane layer in the preparation method of a energy storage battery cell provided by an embodiment of the present application.

[0023] Figure 5 It is the first top view of the membrane layer corresponding to the step of dispensing in the preparation method of a energy storage battery cell provided by an embodiment of the present application.

[0024] Figure 6 It is the second top view of the membrane layer corresponding to the step of dispensing in the preparation method of a energy storage battery cell provided by an embodiment of the present application.

[0025] Figure 7 It is the third top view of the membrane layer corresponding to the step of dispensing in the preparation method of a energy storage battery cell provided by an embodiment of the present application.

[0026] Figure 8 It is a cross-sectional view of the energy storage battery cell corresponding to the step of winding in the preparation method of a energy storage battery cell provided by an embodiment of the present application. Detailed implementation manners

[0027] As can be seen from the background art, at present, the yield of energy storage battery cells is poor and the preparation cost is high.

[0028] Analysis reveals that one of the reasons for the poor yield and high preparation cost of current energy storage battery cells is that the main function of a conventional separator is to separate the cathode (the negative electrode indicated at the negative electrode sheet) and anode (the positive electrode indicated at the positive electrode sheet) materials of the battery, preventing short circuits caused by contact between two electrodes of different polarities. In addition, during the electrochemical reaction, it can maintain the necessary electrolyte to form a channel for ion movement.

[0029] To achieve the fixation between the separator and the positive electrode sheet and between the separator and the negative electrode sheet, a glue layer is generally provided on the base film where the separator is located to form a coated separator. The glue layer has adhesiveness and adheres to the surface of the electrode sheet (positive electrode sheet or negative electrode sheet) after hot pressing, increasing shrinkage resistance and flatness, making the electrode sheet and the separator fit tightly, shortening the lithium ion transmission path, and reducing the interfacial impedance between the electrode sheets. After hot pressing, the glue layer of the coated separator solidifies after cooling, improving the mechanical properties of the wound core composed of the positive electrode sheet, the separator, and the negative electrode sheet, and facilitating assembly.

[0030] However, the use of the coated separator also brings other problems. The separator adheres completely to the surface of the electrode sheet. On the one hand, the surface of the coated separator adheres completely to the surface of the electrode sheet, increasing the amount of the glue layer and raising the cost of the separator. On the other hand, due to the different curvatures of the bending regions of the inner and outer circles of the wound core, the stress in the inner circle is greater, and the possibility of delamination is greater, which makes the separator in the inner circle prone to wrinkling.

[0031] The present application provides a method for preparing an energy storage battery cell, forming a plurality of glue point groups and non-uniformly distributed glue points on the film layer, thereby reducing the preparation cost of the glue and also improving the problem that the inner circle is prone to wrinkling.

[0032] 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 cannot be understood as indicating or implying relative importance or implicitly specifying the quantity, specific order, or primary-secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "a plurality" is more than two, unless otherwise clearly and specifically defined.

[0033] Referring to "embodiments" herein means that specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of the present application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0034] In the description of the embodiments of the present application, the term "and / or" is merely a description of the association relationship between associated objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: the existence of A, the simultaneous existence of A and B, and the existence of B. In addition, the character " / " in this article generally represents an "or" relationship between the associated objects before and after.

[0035] In the description of the embodiments of the present application, the term "plurality" refers to two or more (including two). Similarly, "multiple groups" refers to two or more groups (including two groups), and "multiple pieces" refers to two or more pieces (including two pieces).

[0036] In the description of the embodiments of the present application, the orientation or positional relationship indicated by technical terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the embodiments of the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the embodiments of the present application.

[0037] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installation", "connection", "connection", "fixation", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can also be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0038] In the corresponding drawings of the embodiments of the present application, for better understanding and convenience of description, the thickness and area of the layer are enlarged. 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 "substantially" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor on a partial edge of the entire surface.

[0039] In the description of the embodiments of the present application, when a certain component "includes" another component, unless otherwise specified, other components are not excluded, and other components may further be 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 may be "directly on" another component (i.e., located on the surface of another component with no other components therebetween), or there may be other components 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.

[0040] The terms used in the description of the various embodiments herein are only for the purpose of describing specific embodiments and are not intended to be limiting. As used in the description of the various embodiments and the appended claims, "the part" is also intended to include the plural form unless the context clearly indicates otherwise. Among them, the component includes components such as a layer, film, region, or plate. Thus, the yield of the battery cell is improved.

[0041] Figure 1 It is a flowchart of a method for preparing a storage battery cell provided in an embodiment of the present application.

[0042] According to some embodiments of the present application, on the one hand, an embodiment of the present application provides a method for preparing a storage battery cell. Refer to 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 dotting treatment on the film layer to form the other two of the positive electrode sheet, the separator, or the negative electrode sheet; performing winding treatment on the positive electrode sheet, the negative electrode sheet, and the separator.

[0043] Among them, the film layer has a first edge and a second edge oppositely arranged in a first direction; performing dotting treatment on the film layer so that the surface of the film layer has multiple groups of glue dot groups arranged in the first direction; along the direction from the second edge to the first edge, the distribution density of the glue dot groups decreases; during the winding treatment, winding is performed from the second edge towards the first edge; wherein, the separator 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 groups present a molten state and form an adhesive layer to fix the positive electrode sheet and the separator and / or fix the separator and the negative electrode sheet.

[0044] The preparation method of the energy storage battery cell provided by this application performs dispensing treatment on one of the positive electrode sheet, the separator, or the negative electrode sheet, and arranges the glue dot groups in a specific pattern to relieve 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 separator and between the separator and the negative electrode sheet due to subsequent separator wrinkles, and improving the interface effect. Based on this non-uniform arrangement method, that is, the distribution density of the glue dot groups is smaller 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 a greater adhesive force of the glue dots between the separator and the positive electrode sheet and between the separator and the negative electrode sheet in the inner circle, and then be used to resist the stress caused by the bending curvature, so that the positive electrode sheet and the separator, and the separator and the negative electrode sheet are more closely attached, improving the problem of easy wrinkling of the inner circle of the core at the full charge interface, and can reduce the amount of glue used and lower the preparation cost.

[0045] Classified by shape, the prepared energy storage battery cells can be divided into square battery cells, round battery cells, or soft-pack battery cells. Classified by capacity, the energy storage battery cells can be divided into models such as 50Ah, 100Ah, 150Ah, 200Ah, 280Ah, 306Ah, 314Ah, 500+Ah, 800+Ah, and 1000+Ah. Classified by the chemical composition and working principle of the battery cell, the energy storage battery cell can be a lithium-ion battery, a lead-acid battery, a sodium-ion battery, or a nickel-metal hydride battery. The embodiment of this 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, negative electrode sheet, and electrolyte with corresponding metal ions according to actual needs. For example, for a sodium-ion battery, replace the lithium transition metal oxide of the positive active material in the following with the corresponding layered metal oxide (such as NaFeO 2 ), polyanion compound (NaFePO 4 ), and Prussian blue compound system (such as NaMnFe(CN) 6 -zH 2 O) with any one of them, and replace the electrolyte with any one of organic liquid electrolytes, solid composite electrolytes, or solid electrolytes.

[0046] The following will elaborate on each embodiment of this application in conjunction with the accompanying drawings. However, those of ordinary skill in the art can understand that in each embodiment of this application, many technical details are presented to help readers better understand this application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in this application can still be implemented.

[0047] In some embodiments, the positive electrode sheet and the negative electrode sheet serve as the positive electrode and the negative electrode of the energy storage cell, respectively. The positive electrode is the plate where the oxidation reaction occurs in the energy storage cell, and the negative electrode is the plate where the reduction reaction occurs in the energy storage cell. The positive electrode and the negative electrode are isolated and connected together by an electrolyte, and the positive electrode and the negative electrode serve as the electrochemical reaction region of the energy storage cell.

[0048] 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. A part of the positive electrode current collector is cut into the shape of an electrode tab and serves as the positive electrode tab.

[0049] The positive electrode current collector can be aluminum foil. The price of aluminum foil is lower than that of 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 electrical conduction through the tunneling effect.

[0050] In some embodiments, the positive electrode current collector can also be a composite current collector. The composite current collector includes three stacked layers, with an organic material in the middle layer and copper plating layers and aluminum plating layers on the upper and lower layers. The organic material is PET (polyester), PP (polypropylene), PI (polyimide), etc.

[0051] In some embodiments, the positive electrode current collector can also be a carbon-based current collector, that is, there is a conductive carbon layer 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 improving the life of the current collector; secondly, the conductive carbon layer itself has a low resistivity, so that excessive electrical losses will not occur.

[0052] It should be noted that the carbon-based current collector can be shown as the upper and lower surfaces of the aluminum foil being coated with the conductive carbon layer, or it can be shown as a part of the surface of the aluminum foil being covered with the conductive carbon layer.

[0053] The positive electrode tab is a metal conductor that leads out the positive electrode of the energy storage cell from the cell. The positive electrode tab is the contact point between the positive electrode sheet and the external contact component during the charge and discharge of the cell. The external contact component can be a terminal post.

[0054] 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. A part of the negative electrode current collector is cut into the shape of an electrode tab and serves as the negative electrode tab.

[0055] In some embodiments, the negative electrode current collector can be copper foil. The copper foil has a low conductivity, can have a high electron transport ability, and the lithium intercalation ability of the copper foil is weak, capturing fewer lithium ions, thereby effectively reducing the loss of lithium ions. In some other embodiments, the negative electrode current collector can also be a foam copper current collector, a copper mesh current collector, and a three-dimensional nano-copper array current collector.

[0056] 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 can be classified into two categories: carbon materials and non-carbon materials. Carbon-based materials include two routes: graphite materials (natural graphite, artificial graphite, and mesophase carbon microspheres) and other carbon-based materials (hard carbon, soft carbon, and graphene); non-carbon materials can be further subdivided into titanium-based materials, silicon-based materials, tin-based materials, nitrides, metallic lithium, etc.

[0057] The conductive agent is similar to that of the positive electrode active material layer, and the binder used for the negative electrode is similar to that of 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.

[0058] The negative electrode tab is a metal conductor that leads out the negative electrode of the energy storage battery cell from the battery cell. The negative electrode tab is the contact point between the negative electrode plate and the external contact component during the charge and discharge of the battery cell. The external contact component can be a terminal post.

[0059] The separator is used to prevent short-circuit problems caused by physical contact between the positive electrode plate and the negative electrode plate, and at the same time allows ions to conduct through the electrolyte and hinders electron transmission, so that ions and electrons form a circuit during the charge and discharge process of the battery.

[0060] The separator can be any one of a microporous membrane, a modified microporous membrane, a non-woven separator, and a composite separator. The microporous membrane is a separator with pore diameters in the micron range, mainly including polyolefin microporous membranes and other polymer microporous membranes. The modified microporous membrane is a separator obtained by modifying the microporous membrane, and common modification methods include surface treatment, chemical grafting, surface coating, etc. The non-woven separator has a small fiber diameter and usually exhibits a higher porosity than other types of separators. The composite separator is prepared by coating or filling an inorganic material in a microporous membrane or a non-woven separator, and has higher thermal stability and electrolyte wettability compared to other types of separators.

[0061] Figure 2 This is a preparation flow chart of a membrane layer as a positive electrode plate or a negative electrode plate in the preparation method of an energy storage battery cell provided in an embodiment of the present application; Figure 3 This is a preparation flow chart of a membrane layer as a separator in the preparation method of an energy storage battery cell provided in an embodiment of the present application.

[0062] Reference Figure 2, the film layer is a positive electrode sheet or a negative electrode sheet, and before the glue dispensing process is performed, it also includes: die-cutting the positive electrode sheet or the negative electrode sheet to form a pole ear adjacent to the first edge. In this way, the glue dispensing process 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, the glue dispensing process on the positive electrode sheet / negative electrode sheet can effectively avoid the wrinkle problem caused by the glue dispensing process 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 pole ear can be the positive pole ear of the positive electrode sheet or the negative pole ear of the negative electrode sheet.

[0063] In some embodiments, after the conventional positive electrode sheet and the negative electrode sheet are coated with the active material layer, they are cut into corresponding positive electrode sheets / negative electrode sheets, and then the formed positive electrode sheet and the negative electrode sheet 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 and conveying, 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 circle and the outer circle are distinguished during the subsequent winding process, which is more convenient and quick compared with other distinguishing processes and distinguishing methods. 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.

[0064] refer to Figure 3 The film layer is a diaphragm, and the process steps of performing glue dispensing treatment, forming positive electrode sheets and negative electrode sheets and performing winding treatment include: providing a diaphragm, a positive electrode sheet, and a negative electrode sheet; sequentially loading the diaphragm, the positive electrode sheet, and the negative electrode sheet; performing glue dispensing treatment on the diaphragm; and performing winding treatment on the positive electrode sheet, the negative electrode sheet, and the diaphragm.

[0065] In some embodiments, after the conventional positive electrode sheet and the negative electrode sheet are coated with the active material layer, they are cut into corresponding positive electrode sheets / negative electrode sheets, and then the formed positive electrode sheet and negative electrode sheet 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 and conveying, tab die-cutting, and winding and unwinding. The winding process includes the steps of winding loading, unwinding and conveying, 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 and conveying. 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 circle and the outer circle during the subsequent winding process can be distinguished. Compared with other distinguishing processes and distinguishing methods, it is more convenient and quick.

[0066] The distribution arrangement in the dispensing process provided by the embodiments of the present application will be described below in conjunction with the relevant drawings.

[0067] Figure 4 It is a top view of the film layer corresponding to the film layer provided in the preparation method of an energy storage cell provided by an embodiment of the present application; Figure 5 It is the first top view of the film layer corresponding to the film layer in the dispensing process provided by the preparation method of an energy storage cell provided by an embodiment of the present application; Figure 6 It is the second top view of the film layer corresponding to the film layer in the dispensing process provided by the preparation method of an energy storage cell provided by an embodiment of the present application; Figure 7 It is the third top view of the film layer corresponding to the film layer in the dispensing process provided by the preparation method of an energy storage cell provided by an embodiment of the present application.

[0068] 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 that are oppositely arranged along the first direction X.

[0069] In some embodiments, if the film layer 10 is a positive electrode sheet or a negative electrode sheet, the end portion close to 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.

[0070] Refer to Figure 5 Or Figure 6 , the preparation method includes: performing a dispensing process on the film layer 10 so that the surface of the film layer 10 has multiple groups of glue dot groups arranged along the first direction X; along the direction from the second edge 102 to the first edge 101, the distribution density of the glue dots in the glue dot group decreases. The glue dot group is composed of multiple glue dots arranged at intervals along the second direction.

[0071] In some embodiments, the size of the glue dot is d0, d0 is between 0.1 mm and 0.5 mm, and the size of the glue dot can be any range among 0.1 mm - 0.2 mm, 0.2 mm - 0.3 mm, 0.3 mm - 0.4 mm or 0.4 mm - 0.5 mm. The size of the glue dot can be 0.1 mm, 0.18 mm, 0.23 mm, 0.38 mm, 0.46 mm or 0.5 mm. The size range of the glue dot can make the distribution density of the glue dot group relatively easy to plan, thereby reducing the preparation difficulty of the glue dot. The size range of the glue dot can also prevent the area of the glue dot from being too large, and thus the stress caused by subsequent curing has an adverse effect on the film layer, thereby improving the yield of the energy storage cell.

[0072] In some embodiments, the spacing between two adjacent glue dots is L0, and L0 is between 1d0 and 2d0. L0 can be any value within any of the ranges 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.

[0073] In some embodiments, the spacing between two adjacent glue dot groups is S0, and S0 is between 1.2d0 and 2.5d0. S0 can be any value within any of the ranges 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.

[0074] In some embodiments, the proportion of the total area of the positive projections of the glue dots in multiple groups of glue dot groups on the film layer 10 to the surface area of the film layer 10 is 10% to 14%. The proportion of the total area of the positive 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 proportion of the total area of the positive 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 glue dots are formed within a positive film layer. When 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 more appropriate, thereby achieving the mutual adhesion between the positive electrode sheet and the separator and between the negative electrode sheet and the separator, and avoiding their mutual separation; secondly, the content of the glue is also more appropriate, thereby reducing the preparation cost of the glue and also avoiding the problem of glue overflow.

[0075] In some embodiments, taking the middle position of the film layer along the first direction as the boundary line, the area from the boundary line to the first edge is the sparse area, and the area from the boundary line to the second edge is the dense area. For the dense area, the size of the glue dot is D1, D1 is between 1d0 and 1.2d0, the spacing between two adjacent glue dot groups is S1, S1 is 0.9S0, the spacing between two adjacent glue dots is C1, C1 is 0.9L0, and the proportion of the total area of the glue dots to the area of the film layer is 12% to 16%. For the sparse area, the size of the glue dot is D2, D2 is between 0.8d0 and 1d0, the spacing between two adjacent glue dot groups is S2, S2 is 1.1S0, the spacing between two adjacent glue dots is C2, C2 is 1.3L0, and the proportion of the total area of the glue dots to the area of the film layer is 7% to 11%.

[0076] It should be noted that the spacing refers to the straight-line distance between the center of one glue dot and the center of another glue dot, and the size of the glue dot refers to any value between the minimum distance and the maximum distance of the glue dot.

[0077] In some embodiments, the glue dots of each glue dot group are sequentially formed by an interpolation method. The interpolation method can be a linear interpolation model or a Lagrange interpolation model.

[0078] In some embodiments, referring to Figure 5 , for 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 the spacing of the glue dot groups at different positions also makes the distribution density of the glue dots per unit area different, that is, the distribution density of the first glue dots 121 in the first glue dot group 120 near the first edge 101 is less than the distribution density of the second glue dots 131 in the second glue dot group 130 near the second edge 102, that is, the distribution density of the glue dots near the inner circle is relatively large, thus having a great adhesive force to avoid and resist the stress brought by the winding process, so that the diaphragm and the positive electrode or the diaphragm and the negative electrode in the inner circle will not be delaminated, and thus the diaphragm wrinkles can be avoided.

[0079] In addition, if the spacing is relatively large, the area where the outer circle is located can be used as a gas discharge channel, that is, when the gas released by the electrolyte in the diaphragm, positive electrode and negative electrode of the outer circle can be discharged through the channel formed by two glue dots, thus avoiding the problem of diaphragm wrinkles caused by the bubbles formed by the gas.

[0080] 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. In this way, the spacing ratio of the glue dots in the inner and outer circles is within this range, controlling the relevant parameters of the glue dotting process, so that while reducing the preparation cost, it can ensure a good fit between the diaphragm and the positive electrode to improve the corresponding problems.

[0081] In some embodiments, referring to Figure 6 , the glue dot group includes: the first glue dot group 120 near the first edge 101 and the second glue dot group 130 near the second edge 102, and the size d1 of the first glue dot 121 in the first glue dot group 120 is less than the size d2 of the second glue dot 131 in the second glue dot group 130. In this way, the distribution density of the first glue dot group 120 near the first edge 101 is less than the distribution density of the second glue dot group 130 near the second edge 102, that is, the distribution density of the glue dots near the inner circle is relatively large, thus having a great adhesive force to avoid and resist the stress brought by the winding process, so that the diaphragm and the positive electrode or the diaphragm and the negative electrode in the inner circle will not be delaminated, and thus the diaphragm wrinkles can be avoided.

[0082] Among them, Figure 5The size of each glue dot shown can be the same, i.e., all are the original size d. In some embodiments, the sizes of the glue dots can also be different, but it is required that the distribution density of the glue dot group near the first edge 101 is 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, i.e., all are the original spacing L. In some embodiments, the spacing between adjacent glue dots can also be different, but it is required that the distribution density of the glue dot group near the first edge 101 is less than the distribution density of the glue dot group near the second edge 102. For example, the glue dot spacing within the first glue dot group 120 is greater than the glue dot spacing of the second glue dot group 130.

[0083] It should be noted that Figures 5 to 7 Taking the shape of the glue dot as a circle as an example, but this does not constitute a limitation on the shape and size of the glue dot. Those skilled in the art can design the shape and size of the glue dot according to needs, so as to meet the requirement that the distribution density near the first edge 101 is less than the distribution density near the second edge 102.

[0084] In some embodiments, the film layer 10 further has two third edges 103 oppositely arranged along the second direction Y, and both ends of each third edge 103 are respectively connected to the first edge 101 and the second edge 102; during the process of dotting the film layer 10, from the center of the film layer in the second direction towards the direction close to the third edge, the distribution density of the glue dots in the glue dot group near the third edge 103 is the largest. The large glue dot density on both sides ensures that the edge separator fits more tightly with the positive electrode / negative electrode, improves the friction and interlayer dislocation damage to the side during the subsequent core transfer process, and the impact of the airflow and electrolyte on the core during the injection liquefaction process, and improves the problem of brown spots that are prone to appear at the top and bottom of the core at the full charge interface; it can also reduce the amount of glue used and lower the manufacturing cost.

[0085] In some embodiments, along the second direction Y and in the direction pointing to the third edge 103, the spacing between adjacent glue dots decreases; and / or, refer to Figure 7 , along the second direction and in the direction pointing to the third edge 103, the size of the glue dots increases. For example, the size d21 of the glue dots near the third edge is greater than the size d20 of the glue dots far from the third edge. The decreasing spacing between the glue dots and the increasing size of the glue dots can both make the distribution density increase along the second direction and towards the direction of the third edge 103. In this way, the content of the glue near the edge is larger, and thus the edge of the separator can fit more tightly with the electrode.

[0086] It should be noted that Figure 7Only the second adhesive dots in the second adhesive dot group 130 are schematically shown to present a trend of increasing in size along the second direction and pointing to the third edge 103. However, the first adhesive dots in the first adhesive dot group 120 and the adhesive dots in each group within the first adhesive dot group 120 and the second adhesive dot group 130 may also present this trend, and the embodiments of the present application do not limit this.

[0087] In some embodiments, before winding the positive electrode sheet, the negative electrode sheet, and the separator, the film layer 10 is heat-treated. The heat treatment is at least used to make the adhesive dots of the adhesive dot group present a molten state and pre-fix the positive electrode sheet and the separator and / or pre-fix the negative electrode sheet and the separator. In this way, the adhesive dots on the film layer will be activated and become sticky after heating. During fixing, the subsequent formed battery cell is pre-pressed. The adhesive after pre-pressing is activated and becomes sticky, thereby adhering and fixing the positive electrode sheet / negative electrode sheet and the separator.

[0088] In some embodiments, while winding the positive electrode sheet, the negative electrode sheet, and the separator, it further includes: heat-treating the film layer 10. The heat treatment is at least used to make the adhesive dots of the adhesive dot group present a molten state and form a sticky adhesive layer. Heating while winding, that is, hot winding, can activate the stickiness of the adhesive dots on the film layer, making the subsequent cold pressing process and the winding core forming effect better, and the interface between the separator and the positive electrode sheet fit more closely.

[0089] Reference Figure 8 , the preparation method includes: winding the positive electrode sheet 1, the negative electrode sheet 2, and the separator 3. During the winding process, winding is performed from the second edge 102 towards the first edge 101; wherein, the separator is located between the positive electrode sheet and the negative electrode sheet, and the winding is at least used to make the adhesive dots of the adhesive dot group present a molten state and form a sticky adhesive layer, so as to fix the positive electrode sheet and the separator or fix the separator and the negative electrode sheet.

[0090] In some embodiments, the winding process is to form a single winding core by winding the separator 3, the positive electrode sheet 1, and the negative electrode sheet 2 through a winding machine. The order is to wrap the negative electrode sheet 2 around the positive electrode sheet 1, and then isolate the positive electrode sheet 1 and the negative electrode sheet 2 through the separator 3.

[0091] In some embodiments, if the winding tension is small, it will affect the internal resistance and the shell insertion rate; if the tension is too large, it is easy to cause the risk of short circuit or broken pieces. Therefore, the winding tension is generally 0.08 Mpa to 0.15 Mpa for the positive tension, 0.08 Mpa to 0.15 Mpa for the negative tension, 0.08 Mpa to 0.15 Mpa for the upper separator tension, and 0.08 Mpa to 0.15 Mpa for the lower separator tension. The widths of the negative electrode sheet 2, the positive electrode sheet 1, and the separator 3 are not the same. For example, the width of the negative electrode sheet is 59.5 mm, the positive electrode sheet is 58 mm, and the separator is 61 mm. The three are set to be centered and aligned to improve the alignment degree of the electrode sheets and avoid the risk of short circuit. The alignment degree of the electrode sheets refers to the relative positions of the positive electrode sheet 1, the negative electrode sheet 2, and the separator 3.

[0092] In some embodiments, the process steps of the winding process include: a hot winding process and a cold pressing process. The hot winding process is used to make the adhesive dots of the adhesive dot group present in a molten state and form an adhesive layer to fix the positive electrode sheet to the separator and / or fix the separator to the negative electrode sheet; the cold pressing process is used to bond the positive electrode sheet, the negative electrode sheet, and the separator pairwise.

[0093] It should be noted that, for the purpose of illustration and distinction among the separator, the positive electrode sheet, and the negative electrode sheet, Figure 8 the separator is schematically shown by a dotted line, the negative electrode sheet is schematically shown by a thinner solid line, and the positive electrode sheet is schematically shown by a thicker solid line, but this does not represent the thickness relationship among the separator, the positive electrode sheet, and the negative electrode sheet. Secondly, Figure 8 there are gaps between the separator 3, the positive electrode sheet 1, and the negative electrode sheet 2 pairwise. This is to clearly show the winding correspondence relationship among the separator 3, the positive electrode sheet 1, and the negative electrode sheet 2, but it does not mean that there must be gaps between the separator 3 and the positive electrode sheet 1 or between the separator 3 and the negative electrode sheet 2. That is to say, 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.

[0094] The preparation method of the energy storage battery cell further includes: placing the whole formed by winding the positive electrode sheet 1, the negative electrode sheet 2, and the separator 3 in the chamber formed by the outer shell, and the chamber is also filled with an electrolyte.

[0095] The electrolyte is a carrier for conducting electrons between the positive and negative electrodes of the battery. In some embodiments, the electrolyte can be an electrolyte solution, which is composed of 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); carboxylic acid esters (MF, MA, EA, MA, MP, etc.). The lithium salt can be LiPF 6 、LiClO 4 、LiBF 4 、LiAsF 6 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 H 2 O and HF in the electrolyte, an additive for improving low-temperature performance, and a multifunctional additive.

[0096] The preparation method includes: welding the tab, welding the tab to the adapter plate, and connecting the other end of the adapter plate to the terminal; engaging the ejector rod with the outer shell. Among them, the adapter plate is located in the chamber, and the terminal passes through the top cover.

[0097] Among them, the adapter piece at least includes a first adapter piece and a second adapter piece. The pole column includes a positive pole column and a negative connection column. The first adapter piece is electrically connected to the tab of the positive electrode plate and the positive pole column respectively, and the second adapter piece is electrically connected to the negative tab of the negative electrode plate and the negative pole column respectively.

[0098] The preparation method of the energy storage battery cell provided by this application performs glue dotting treatment on one of the positive electrode plate 1, the separator 3, or the negative electrode plate 2, and arranges the glue dot groups in a specific pattern to relieve and offset the stress problem caused by the bending area of the wound core, so as to avoid the problem of wrinkles at the interface between the positive electrode plate and the separator and at the interface between the separator and the negative electrode plate caused by subsequent separator wrinkles, thereby improving the interface effect. Based on this non-uniform arrangement method, that is, the distribution density of the glue dot groups is smaller the closer it is to the first edge 101, that is, the distribution density is smaller at the position closer to the outer circle of the wound core, which can ensure that the adhesion of the glue dots between the separator and the positive electrode plate and between the separator and the negative electrode plate in the inner circle is greater, and then used to resist the stress caused by the bending arc, so that the positive electrode plate and the separator, and the separator and the negative electrode plate are more closely attached, improving the problem of easy wrinkling of the inner circle of the wound core at the full charge interface, and can reduce the amount of glue used and reduce the preparation cost.

[0099] Correspondingly, according to some embodiments of this application, on the other hand, this application embodiment also provides an energy storage battery cell, which can be prepared by using the preparation method provided by the above embodiments. The same or corresponding technical features as those in the above embodiments will not be elaborated in detail here.

[0100] Reference Figure 8 and Figure 7 , the energy storage battery cell includes: a positive electrode plate 1, a negative electrode plate 2, and a separator 3, and the separator 3 is located between the positive electrode plate 1 and the negative electrode plate 2; there is an adhesive layer 140 between the positive electrode plate 1 and the separator 3 or between the negative electrode plate 2 and the separator 3, and the positive electrode plate 1 and the separator 3 are fixed through the adhesive layer 140 and / or the negative electrode plate 2 and the separator 3 are fixed through the adhesive layer 140; an adhesive group, the adhesive group includes a plurality of adhesive layers 140; along the winding direction from the inner circle to the outer circle, the distribution density of the adhesive group decreases.

[0101] Among them, the inner circle refers to the inner circle of the formed wound core structure, corresponding to Figure 6 the second edge; the outer circle refers to the outer circle of the formed wound core structure, corresponding to Figure 6 the first edge in

[0102] For the energy storage battery cell provided by the embodiment of the present application, the glue is unevenly distributed, and the positive electrode sheet or negative electrode sheet corresponding to the outer ring and the separator are not completely adhered, so that there are microscopically channels between the positive electrode sheet / negative electrode sheet or between the positive electrode sheets, and the electrolyte can directly flow 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, reducing the infiltration difficulty of the battery cell, thereby improving the yield of the energy storage battery cell. Moreover, this channel can also serve as a gas accommodation area, so that the gas generated during the charge and discharge of the battery cell stays in the gas accommodation area, which can reduce the impact of the gas on the separator and prevent the separator from separating from the electrode sheet. The gas accommodation area can also serve as a buffer area to facilitate the gas to ooze out. Especially when the battery cell is not working, the gas continuously oozes out from the gas accommodation area to empty the gas accommodation area, so that after the gas is generated during the charge and discharge of the battery cell, the gas can converge in the gas accommodation area again.

[0103] Those of ordinary skill in the art can understand that the above embodiments are specific embodiments for implementing the present application. In actual applications, various changes can be made in form and details without departing from the spirit and scope of the present application. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application. Therefore, the protection scope of the present application should be subject to the scope defined by 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 that are arranged opposite to each other along a first direction; Performing glue dot processing on the film layer so that the surface of the film layer has a plurality of glue dot groups arranged along a first direction; Along the direction from the second edge to the first edge, the distribution density of the glue point group decreases; Wherein, the glue point group includes: a first glue point group close to the first edge and a second glue point group close to the second edge, the size of the first glue point in the first glue point group is smaller than the size of the second glue point in the second glue point group; and / or, the first spacing between adjacent first glue points in the first glue point group is larger than the second spacing between adjacent second glue points in the second glue point group; 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; in the process of performing glue dispensing treatment on the film layer, the distribution density of the glue points in the same glue point group increases from the center of the film layer in the second direction toward the third 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, and the winding process is 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 make the glue points of the glue point group present a molten state and form an adhesive layer, so as to fix the positive electrode sheet to the separator and / or fix the separator to the negative electrode sheet; Among them, the first edge is the edge of the outer circle of the winding core formed by the winding process, and the second edge is the edge of the inner circle of the winding 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, characterized in that: 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.

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

3.

4. The method for preparing the energy storage battery cell according to claim 1, characterized in that: 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%.

5. The method for preparing the energy storage battery cell according to claim 1, characterized in that: 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 a molten state and form the 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 make the positive electrode sheet, the negative electrode sheet and the diaphragm fit each other.

6. The method for preparing the energy storage battery cell according to claim 1, characterized in that: Before winding the positive electrode sheet, the negative electrode sheet and the separator, the film layer is subjected to a heating treatment, wherein 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.

7. The method for preparing the energy storage battery cell according to claim 1, characterized in that: While the positive electrode sheet, the negative electrode sheet and the separator are being wound, the method further includes: 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.

8. An energy storage battery cell prepared by the method for preparing an energy storage battery cell according to any one of claims 1 to 7, 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 through the adhesive layer and / or the negative electrode sheet and the separator are fixed to each other through the adhesive layer; An adhesive group, the adhesive group comprising a plurality of adhesive layers; Along the winding direction from the inner circle to the outer circle, the distribution density of the adhesive group decreases, so that the adhesion between the adhesive points of the inner circle's diaphragm and the positive electrode sheet and between the diaphragm and the negative electrode sheet is greater than the adhesion between the adhesive points of the outer circle's diaphragm and the positive electrode sheet and between the diaphragm and the negative electrode sheet.

Images