Battery, battery pack and energy storage system

Abstract

The utility model provides a battery, a battery pack and an energy storage system, and relates to the technical field of energy. The battery provided by the utility model comprises a battery cell, the battery cell comprises an insulating flexible film, N groups of positive pole pieces and N + 1 groups of negative pole pieces, the N groups of positive pole pieces and the N + 1 groups of negative pole pieces are alternately arranged in a laminated manner, and N is an integer greater than or equal to 1. The two positive pole pieces of each group of positive pole pieces are respectively positioned on the two surfaces of the insulating flexible film, and the two positive pole pieces are arranged in a back-to-back manner. The two negative pole pieces of each group of negative pole pieces are respectively positioned on the two surfaces of the insulating flexible film, and the two negative pole pieces are arranged in a back-to-back manner. According to the battery provided by the invention, the positive pole piece and the negative pole piece of the battery cell share one insulating flexible thin film, so that the energy density of the battery cell is improved, and the risks of breakage of the battery cell and ion precipitation can be reduced by enabling the insulating flexible thin film to be positioned at the corner of the battery cell; the reliability of the structure and the charge-discharge performance of the battery cell is effectively improved, so that the operation reliability of the battery is improved.

Description

Technical Field

[0001] The present application relates to the field of energy technology, and in particular to a battery, a battery pack and an energy storage system. Background Art

[0002] At present, the bare cells of lithium-ion batteries and sodium-ion batteries are usually wound structures or laminated structures. Among them, the winding structure is a structure formed by arranging a positive electrode sheet, a separator, a negative electrode sheet and a separator in sequence and winding them up. The laminated structure is a structure formed by alternating arrangement of N positive electrode sheets, N+1 negative electrode sheets and 2N+2 separators. The advantage of the wound structure of the battery cell is that the electrode sheets and separators are continuous, and it takes a short time to wind them into a roll; but because the corners of the roll core are not subjected to force, there is a risk of lithium / sodium precipitation and fracture during the expansion of the electrode sheets. The laminated core can make full use of the internal space of the battery shell, thereby improving the energy density of the battery; but the electrode sheets of the laminated core are cut separately, which is prone to burrs, and has high requirements for cutting tools. Utility Model Content

[0003] The present application provides a battery, a battery pack and an energy storage system to improve the energy density and structural reliability of the battery and improve the production efficiency of the battery, which is conducive to reducing the cost of the battery pack and energy storage system using the battery.

[0004] In a first aspect, the present application provides a battery, which includes a battery cell, and the battery cell includes an insulating flexible film, N groups of positive electrode sheets and N+1 groups of negative electrode sheets, where N is an integer greater than or equal to 1. Among them, the N groups of positive electrode sheets and the N+1 groups of negative electrode sheets share a common insulating flexible film. Specifically, each group of positive electrode sheets includes two positive electrode sheets, and the two positive electrode sheets are respectively located on the two surfaces of the insulating flexible film, and the two positive electrode sheets are arranged back to back. Each group of negative electrode sheets includes two negative electrode sheets, and the two negative electrode sheets are respectively located on the two surfaces of the insulating flexible film, and the two negative electrode sheets are arranged back to back. In addition, the above-mentioned N groups of positive electrode sheets and N+1 groups of negative electrode sheets are stacked, and each group of positive electrode sheets is located between two adjacent negative electrode sheets along the stacking direction. In the battery provided in the present application, the N groups of positive electrode sheets and the N+1 groups of negative electrode sheets of the battery cell share a common insulating flexible film, which can make the N groups of positive electrode sheets and the N+1 groups of negative electrode sheets arranged alternately along the stacking direction to improve the energy density of the battery cell. At the same time, since the battery cell cancels the electrode sheet setting at the corner, it can avoid the problems of lithium and sodium precipitation caused by cracking and decarbonization of the corner electrode sheets, so as to effectively improve the structure of the battery cell and the reliability of the charge and discharge performance, which can be beneficial to improving the operation reliability of the battery.

[0005] In a possible implementation of the present application, the battery cell is a winding structure, and the battery may include a separator, and along the stacking direction, a separator covers each positive electrode sheet and each negative electrode sheet. This can effectively avoid the direct contact between adjacent positive and negative electrode sheets to cause a short circuit.

[0006] In a possible implementation of the present application, the insulating flexible film includes 2N+1 pole piece setting areas and 2N non-pole piece setting areas, each non-pole piece setting area is located between two adjacent pole piece setting areas, and N groups of positive pole pieces and N+1 groups of negative pole pieces are arranged in 2N+1 pole piece setting areas in a one-to-one correspondence. In addition, along the arrangement direction of the 2N+1 pole piece setting areas and the 2N non-pole piece setting areas, the length of the non-pole piece setting area is greater than or equal to 1.3×n×(Ta+Tc+Ts), wherein Ta is the thickness of each negative pole piece along the stacking direction, Tc is the thickness of each positive pole piece along the stacking direction, Ts is the thickness of a diaphragm along the stacking direction, n is the order of the non-pole piece setting areas starting from the center of the battery cell, and n is an integer greater than or equal to 1. In the wound structure battery cell, the insulating flexible film is designed in this way, which can make N groups of positive pole sheets and N+1 groups of negative pole sheets arranged alternately along the stacking direction, and the non-pole sheet setting area of ​​the insulating flexible film is located at the corner of the battery cell. This can effectively reduce the risk of ion precipitation and fracture of the battery cell during the expansion of the pole sheets, thereby improving the reliability of the battery cell structure and charging and discharging performance.

[0007] In a possible implementation of the present application, the battery cell may also be a serpentine bending structure, which may be prepared by a lamination process. However, since the positive and negative pole pieces of the battery cell are formed on the same insulating flexible film, when N groups of positive pole pieces and N+1 groups of negative pole pieces are stacked to form the battery cell, there is no need to cut the positive and negative pole pieces, which can effectively reduce the probability of burrs, thereby improving the product yield and production efficiency of the battery cell and reducing processing costs.

[0008] In addition, the battery cell of the serpentine bending structure may include 2N+2 separators, wherein each group of negative electrode sheets is located between two separators, and each group of positive electrode sheets is located between two separators. This can effectively avoid the direct contact between adjacent positive electrode sheets and negative electrode sheets to cause a short circuit.

[0009] In a possible implementation of the present application, in the battery cell with the above-mentioned serpentine bending structure, the insulating flexible film also includes 2N+1 pole piece setting areas and 2N non-pole piece setting areas, each non-pole piece setting area is located between two adjacent pole piece setting areas, and N groups of positive pole pieces and N+1 groups of negative pole pieces are arranged in 2N+1 pole piece setting areas in a one-to-one correspondence. In addition, along the arrangement direction of the 2N+1 pole piece setting areas and the 2N non-pole piece setting areas, the length of each non-pole piece setting area is greater than or equal to 1.3×(Ta+Tc+Ts), where Ta is the thickness of each negative pole piece along the stacking direction, Tc is the thickness of each positive pole piece along the stacking direction, and Ts is the thickness of each diaphragm along the stacking direction. In this way, the N groups of positive electrode sheets and the N+1 groups of negative electrode sheets can be arranged alternately along the stacking direction, and the non-electrode sheet setting area of ​​the insulating flexible film can be located at the bend of the battery cell. This can effectively reduce the risk of ion precipitation and fracture of the battery cell during the expansion of the electrode sheets, thereby improving the reliability of the battery cell structure and charging and discharging performance.

[0010] In a possible implementation of the present application, each positive electrode plate includes a positive electrode current collector and a positive electrode active material layer, the positive electrode current collector is arranged on the surface of the insulating flexible film, and the positive electrode active material is arranged on the surface of the positive electrode current collector away from the insulating flexible film. Similarly, each negative electrode plate includes a negative electrode current collector and a negative electrode active material, the negative electrode current collector is arranged on the surface of the insulating flexible film, and the negative electrode active material is arranged on the surface of the negative electrode current collector away from the insulating flexible film. In this way, the charge and discharge function of the battery cell can be realized through the chemical reaction of the negative electrode active material of the negative electrode plate of the battery cell and the positive electrode active material of the positive electrode plate with the electrolyte in the battery.

[0011] In a possible implementation of the present application, the length of the negative electrode current collector is 100 mm to 1000 mm, which can be specifically set according to the application scenario. The length of the positive electrode current collector is 1 mm to 100 mm smaller than the length of the negative electrode current collector. This is conducive to making the size of the negative electrode plate in the length direction larger than the size of the positive electrode plate in the same direction, so that the negative electrode plate is closer to the edge of the battery cell relative to the positive electrode plate in the length direction, which is conducive to reducing the risk of ion precipitation in the battery cell, thereby improving the stability of the charge and discharge performance of the battery cell.

[0012] In addition, the width of the negative electrode current collector is 50 mm to 600 mm, and the width of the positive electrode current collector is 1 mm to 50 mm smaller than the width of the negative electrode current collector, wherein the width direction is perpendicular to the length direction. Then the dimension of the negative electrode sheet in the width direction is larger than the dimension of the positive electrode sheet in the same direction, so that the negative electrode sheet is closer to the edge of the battery cell relative to the positive electrode sheet in the width direction, which is beneficial to reduce the risk of ion precipitation in the battery cell, thereby improving the stability of the charge and discharge performance of the battery cell.

[0013] In a possible implementation of the present application, the battery cell further includes a positive electrode ear and a negative electrode ear, the positive electrode ear is electrically connected to the positive electrode collector, and the negative electrode ear is electrically connected to the negative electrode collector.

[0014] In addition, the battery also includes a battery case and a cover plate, the battery cell is contained in the battery case, and the cover plate is disposed on the battery case. The cover plate includes a positive electrode column and a negative electrode column, the positive electrode column is electrically connected to the positive electrode ear, and the negative electrode column is electrically connected to the negative electrode ear. In this way, the positive electrode ear and the negative electrode ear of the battery cell can be led out of the battery case through the positive electrode column and the negative electrode column of the cover plate, so as to realize the electrical connection between the battery and the electrical device or the power supply device.

[0015] In a possible implementation of the present application, the width of the negative electrode active material layer is smaller than the width of the negative electrode current collector, and one end of the negative electrode current collector not covered by the negative electrode active material layer in the width direction serves as the negative electrode ear. Similarly, the width of the positive electrode active material layer is smaller than the width of the positive electrode current collector, and one end of the positive electrode current collector not covered by the positive electrode active material layer in the width direction serves as the negative electrode ear. This can effectively simplify the structure of the battery cell.

[0016] In a possible implementation of the present application, the material of the negative electrode current collector is copper or aluminum, and the material of the positive electrode current collector is aluminum. The material can be selected according to the specific application scenario as long as the negative electrode current collector and the positive electrode current collector have good conductivity.

[0017] In addition, the material of the insulating flexible film is one of polyamide, polyethylene terephthalate, polytetrafluoroethylene, polyvinylidene fluoride, polyimide, polyethylene, polypropylene, polystyrene, polyvinyl chloride or polypropylene, so as to avoid short circuit between N groups of positive pole pieces and N+1 groups of negative pole pieces arranged on the same insulating flexible film, and at the same time, the battery cell can have better structural reliability.

[0018] In a second aspect, the present application further provides a battery pack, which includes a plurality of batteries according to the first aspect, any two of the plurality of batteries being connected in series or in parallel. The battery pack provided by the present application has a low cost and has better structural reliability and charge and discharge performance.

[0019] In the third aspect, the present application also provides an energy storage system, which includes an energy storage converter and an energy storage cabinet, wherein the energy storage cabinet includes one or more battery packs as in the second aspect, and the energy storage converter is electrically connected to the energy storage cabinet, and is used to convert the AC power output by an external power source into DC power and then provide it to the energy storage cabinet, or to convert the DC power from the energy storage cabinet into AC power and output it to an external device. Since the structure and charging and discharging performance of the battery pack of the energy storage system provided by the present application are relatively reliable, it is conducive to improving the operational reliability of the energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the structure of a battery provided in an embodiment of the present application;

[0021] Figure 2 A schematic diagram of the structure of a battery cell provided in an embodiment of the present application;

[0022] Figures 3a to 3e A schematic diagram of a preparation process of a battery cell provided in an embodiment of the present application;

[0023] Figure 4 Another schematic diagram of the structure of a battery cell provided in an embodiment of the present application;

[0024] Figure 5 A schematic diagram of the structure of an energy storage cabinet provided in an embodiment of the present application.

[0025] Reference numerals:

[0026] 100-battery pack; 10-battery; 1-battery cell; 101-positive electrode ear; 102-negative electrode ear; 103-insulating flexible film; 1031-electrode piece setting area;

[0027] 1032- non-pole plate setting area; 104- positive electrode plate; 1041- positive electrode current collector; 1042- positive electrode active material layer; 105- negative electrode plate;

[0028] 1051-negative electrode current collector; 1052-negative electrode active material layer; 106-diaphragm; 2-battery shell; 3-cover plate; 301-positive electrode column; 302-negative electrode column;

[0029] 200-Energy storage cabinet. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings. However, the example embodiments can be implemented in various forms and should not be construed as being limited to the embodiments described herein. The same reference numerals in the figures represent the same or similar structures, and thus their repeated description will be omitted. The words expressing position and direction described in the embodiments of the present application are all illustrated by taking the accompanying drawings as examples, but changes may be made as needed, and the changes made are all included in the scope of protection of the present application. The drawings of the embodiments of the present application are only used to illustrate the relative position relationship, and they do not represent the true proportion.

[0031] It should be noted that specific details are described in the following description to facilitate understanding of the present application. However, the present application can be implemented in a variety of other ways different from those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present application. Therefore, the present application is not limited to the specific implementation methods disclosed below.

[0032] In order to facilitate the understanding of the battery provided in the embodiments of the present application, its application scenario is first introduced below. When an electronic device is in use, a power supply device is usually required to power it. At present, various electronic devices, such as consumer electronic products (such as mobile phones, tablets or wearable devices) and electric vehicles, etc., can usually choose secondary batteries such as lithium batteries, lead-acid batteries, sodium batteries, magnesium batteries, aluminum batteries and potassium batteries as power supply devices. In addition, batteries are also used as basic units for energy storage systems such as energy storage base stations to realize charging and discharging functions. In this application, secondary batteries (rechargeable battery) are also called rechargeable batteries, power batteries or storage batteries, which refer to batteries that can be activated by charging after the battery is discharged and continue to be used. In the following embodiments of the present application, unless otherwise specified, the batteries mentioned refer to secondary batteries.

[0033] Taking sodium batteries as an example, sodium batteries have been increasingly widely used in the field of energy storage because of their high energy density and low cost. The main energy storage component in sodium batteries is the battery cell. At present, the battery cell of sodium batteries is mainly a winding core or a stacked core of a laminated structure. The core is formed by arranging a positive electrode sheet, a separator, a negative electrode sheet and a separator in sequence and winding them up. It has high production efficiency, but because the corners of the core are not subjected to force, there is a risk of sodium precipitation and breakage during the expansion of the electrode sheet. The stacked core is a structure formed by arranging a separator, a negative electrode sheet, a separator, a positive electrode sheet, a separator, a negative electrode sheet and a separator in sequence. The stacked core can make full use of the space inside the battery shell, which is conducive to the improvement of the battery's energy density. However, since the electrodes of the stacked core are cut separately, burrs are easily generated, and the cutting tool requirements are high, so its production efficiency is low and the processing cost is high.

[0034] In view of this, the battery cell provided by the present application is configured such that the positive electrode sheet and the negative electrode sheet are alternately arranged on the surface of the same insulating flexible film, and the positive electrode sheet and the negative electrode sheet of the battery cell are alternately arranged along the stacking direction through a winding or lamination process, which can improve the production efficiency and energy density of the battery cell. Furthermore, since neither the positive electrode sheet nor the negative electrode sheet is arranged at the corner of the battery cell, the risk of ion precipitation and fracture of the battery cell can be effectively reduced, so as to improve the reliability of the structure of the battery cell and the charge and discharge performance, and help to extend the service life of the battery. The battery provided in the embodiment of the present application will be described in detail below in conjunction with the accompanying drawings.

[0035] Reference Figure 1 , Figure 1A schematic diagram of the structure of a battery 10 provided in an embodiment of the present application. The battery 10 includes a battery cell 1, a battery shell 2, and a cover plate 3, wherein the battery cell 1 is contained in the battery shell 2, and the cover plate 3 is covered on the battery shell 2 to encapsulate the battery cell 1 in a closed chamber formed by the cover plate 3 and the battery shell 2. In addition, the battery shell 2 also includes an electrolyte, and the positive electrode sheet ( Figure 1 Not shown) and the negative electrode sheet ( Figure 1 The battery cell 1 is immersed in the electrolyte (not shown) to realize the charge and discharge of the battery cell 1 through the chemical reaction between the positive electrode sheet and the negative electrode sheet and the electrolyte.

[0036] You can continue to refer to Figure 1 , the cover plate 3 includes a positive electrode column 301 and a negative electrode column 302, the battery cell 1 includes a positive electrode ear 101 and a negative electrode ear 102, the positive electrode ear 101 is electrically connected to the positive electrode plate, the positive electrode column 301 is electrically connected to the positive electrode ear 101; the negative electrode ear 102 is electrically connected to the negative electrode plate, and the negative electrode column 302 is electrically connected to the negative electrode ear 102. In this way, the positive electrode ear 101 and the negative electrode ear 102 of the battery cell 1 can be led out to the outside of the battery case 2 through the positive electrode column 301 and the negative electrode column 302 of the cover plate 3, so as to realize the electrical connection between the battery 10 and the electrical equipment or power supply equipment.

[0037] The battery cell 1 is the main component of the battery 10 to realize the charging and discharging functions. Figure 2 , Figure 2 A schematic diagram of the structure of a battery cell 1 of a battery 10 provided in an embodiment of the present application, Figure 2 The battery cell 1 shown is formed based on a winding process. The battery cell 1 includes an insulating flexible film 103, N groups of positive electrode sheets 104 and N+1 groups of negative electrode sheets 105, wherein N is an integer greater than or equal to 1. In the battery cell 1 provided in the embodiment of the present application, the insulating flexible film 103 is one sheet, and the N groups of positive electrode sheets 104 and the N+1 groups of negative electrode sheets 105 are all arranged on the same insulating flexible film 103. In a specific implementation, each group of positive electrode sheets 104 includes two positive electrode sheets 104, and the two positive electrode sheets 104 are respectively located on two surfaces of the insulating flexible film 103, and the two positive electrode sheets 104 are arranged back to back. Each group of negative electrode sheets 105 includes two negative electrode sheets 105, and the two negative electrode sheets 105 are respectively located on two surfaces of the insulating flexible film 103, and the two negative electrode sheets 105 are arranged back to back.

[0038] It is worth mentioning that the insulating flexible film 103 also serves as a carrier for the N group of positive electrode sheets 104 and the N+1 group of negative electrode sheets 105. It can be exemplarily one of polyamide, polyethylene terephthalate, polytetrafluoroethylene, polyvinylidene fluoride, polyimide, polyethylene, polypropylene, polystyrene, polyvinyl chloride or polypropylene, so as to avoid short circuit between the N group of positive electrode sheets 104 and the N+1 group of negative electrode sheets 105 arranged on the same insulating flexible film 103, and at the same time, the battery cell 1 can have better structural reliability.

[0039] In addition, the thickness of the insulating flexible film 103 can be set smaller according to the material used, etc., which is conducive to reducing the space occupied by the insulating flexible film 103, thereby facilitating the miniaturization design of the battery cell 1 and the battery 10. And when the space for arranging the battery cell 1 in the battery 10 is certain, it can meet the requirements of arranging more sets of positive electrode sheets 104 and more sets of negative electrode sheets 105 of the battery cell 1, thereby facilitating improving the energy density of the battery 10.

[0040] In the embodiment of the present application, the positive electrode plate 104 may include a positive electrode collector 1041 and a positive electrode active material layer 1042, the positive electrode collector 1041 is arranged on the surface of the insulating flexible film 103, and the positive electrode active material layer 1042 is arranged on the surface of the positive electrode collector 1041 away from the insulating flexible film 103; the negative electrode plate 105 may include a negative electrode collector 1051 and a negative electrode active material layer 1052, the negative electrode collector 1051 is arranged on the surface of the insulating flexible film 103, and the negative electrode active material layer 1052 is arranged on the surface of the negative electrode collector 1051 away from the insulating flexible film 103. Among them, the positive electrode current collector 1041 and the negative electrode current collector 1051 can be metal conductive layers, and the materials of the two can be the same or different. For example, when the battery 10 is a sodium battery, the positive electrode current collector 1041 and the negative electrode current collector 1051 can both be aluminum conductive layers; for example, when the battery 10 is a lithium battery, the positive electrode current collector 1041 is an aluminum conductive layer, and the negative electrode current collector 1051 can be a copper conductive layer.

[0041] In addition, the positive electrode active material layer 1042 can be, for example, lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, lithium iron manganese phosphate, lithium iron phosphate or a ternary material, and the negative electrode active material layer 1052 can be, for example, graphite, etc., which can be specifically selected according to the specific application scenario.

[0042] You can continue to refer to Figure 2 In the battery cell 1, N groups of positive electrode sheets 104 and N+1 groups of negative electrode sheets 105 are stacked, and each group of positive electrode sheets 104 is located between two adjacent groups of negative electrode sheets 105 along the stacking direction. In order to avoid short circuit between the positive electrode sheets 104 and the negative electrode sheets 105 adjacent to each other along the stacking direction, the battery cell 1 provided in the embodiment of the present application further includes a separator 106, and Figure 2 The battery cell 1 shown may include only one separator 106 , which is also in a winding structure, so as to be wound between N groups of positive electrode sheets 104 and N+1 groups of negative electrode sheets 105 , thereby covering each positive electrode sheet 104 and each negative electrode sheet 105 .

[0043] To facilitate this application Figure 2 The design of the battery cell 1 shown in the figure is understood, and then combined with Figures 3a to 3e The structure of the battery cell 1 is further introduced by referring to the preparation process of the battery cell 1 shown in FIG.

[0044] First, refer to Figure 3a , Figure 3a The steps of forming positive electrode current collector 1041 and negative electrode current collector 1051 on the same insulating flexible film 103 are shown. In specific implementation, the insulating flexible film 103 can be flattened, and N groups of positive electrode current collectors 1041 and N+1 groups of negative electrode current collectors 1051 are formed on the insulating flexible film 103 along the length direction of the insulating flexible film 103. Figure 3a It can be represented as the X direction, which is also the direction in which the N group of positive current collectors 1041 and the N+1 group of negative current collectors 1051 are arranged. In addition, in the present application, the positive current collector 1041 can be formed on the insulating flexible film 103 by, but not limited to, evaporation, vapor deposition, or pasting processes; similarly, the negative current collector 1051 can be formed on the insulating flexible film 103 by, but not limited to, evaporation, vapor deposition, or pasting processes. And the formation methods of the positive current collector 1041 and the negative current collector 1051 can be the same or different.

[0045] You can continue to refer to Figure 3a Each group of positive current collectors 1041 includes two positive current collectors 1041, which are respectively located on two surfaces of the insulating flexible film 103, and the two positive current collectors 1041 are arranged opposite to each other; each group of negative current collectors 1051 includes two negative current collectors 1051, which are respectively located on two surfaces of the insulating flexible film 103, and the two negative current collectors 1051 are arranged opposite to each other. In the embodiment of the present application, the connection method of the positive current collector 1041 and the negative current collector 1051 and the insulating flexible film 103 is not limited, and it can be exemplarily bonded.

[0046] In addition, if Figure 3aAs shown, in the X direction, the first and last positions of the arrangement order of the N groups of positive current collectors 1041 and the N+1 groups of negative current collectors 1051 are both negative current collectors 1051. In addition, it can be understood that in order to enable the N groups of positive current collectors 1041 and the N+1 groups of negative current collectors 1051 in the wound battery cell 1 to be alternately arranged in the stacking direction, as shown in FIG. Figure 3a As shown, the arrangement order of N groups of positive current collectors 1041 and N+1 groups of negative current collectors 1051 formed on the insulating flexible film 103 may be: negative current collector 1051-positive current collector 1041-positive current collector 1041-negative current collector 1051-negative current collector 1051-positive current collector 1041-positive current collector 1041…negative current collector 1051-negative current collector 1051.

[0047] It is worth mentioning that since the two opposite surfaces of the insulating flexible film 103 are to form the positive electrode current collector 1041 and the negative electrode current collector 1051, Figure 3a In the steps shown, N positive current collectors 1041 and N+1 negative current collectors 1051 may be formed on one surface of the insulating flexible film 103 first, and then N positive current collectors 1041 and N+1 negative current collectors 1051 may be formed on the other surface of the insulating flexible film 103; or, two positive current collectors 1041 of each group of positive current collectors 1041 are simultaneously formed on the surface of the insulating flexible film 103, and two negative current collectors 1051 of each group of negative current collectors 1051 are simultaneously formed on the surface of the insulating flexible film 103. In the present application, the specific formation order of the N groups of positive current collectors 1041 and the N+1 groups of negative current collectors 1051 is not limited.

[0048] Reference Figure 3b , Figure 3b for Figure 3a A top view of the structure shown in FIG. Figure 3a The arrangement of the positive electrode current collector 1041 and the negative electrode current collector 1051 on one surface of the insulating flexible film 103 after the step shown. Figure 3b As shown, along the X direction, the length L1 of the negative electrode current collector 1051 can be 100 mm to 1000 mm, and the width W1 of the negative electrode current collector 1051 can be 50 mm to 600 mm, wherein the width direction of the negative electrode current collector 1051 is perpendicular to the length direction. The size of the negative electrode current collector 1051 can be specifically set according to the application scenario, so that the area of ​​the negative electrode current collector 1051 is larger while meeting the size requirements of the battery cell 1, which is conducive to increasing the size of the negative electrode sheet 105, thereby facilitating the improvement of the energy density of the battery cell 1.

[0049] You can continue to refer to Figure 3b, the length L2 of the positive current collector 1041 is 1 mm to 100 mm smaller than the length L1 of the negative current collector 1051, and the width L2 of the positive current collector 1041 is 1 mm to 50 mm smaller than the width L1 of the negative current collector 1051. In this way, the dimensions of the negative electrode sheet 105 in the length and width directions are larger than the dimensions of the positive electrode sheet 104 in the corresponding directions, so that in the wound battery cell 1, the negative electrode sheet 105 can be closer to the edge of the battery cell 1 relative to the positive electrode sheet 104 in both the width direction and the length direction, which is conducive to reducing the risk of ion precipitation in the battery cell 1, thereby improving the stability of the charge and discharge performance of the battery cell 1.

[0050] Reference Figure 3c , Figure 3c Shown in Figure 3a The steps of forming the positive electrode active material layer 1042 and the negative electrode active material layer 1052 on the basis of the structure shown in FIG. In specific implementation, the positive electrode active material layer 1042 is formed on the surface of each positive electrode collector 1041 away from the insulating flexible film 103, and the negative electrode active material layer 1052 is formed on the surface of each negative electrode collector 1051 away from the insulating flexible film 103, thereby forming N positive electrode sheets 104 and N+1 negative electrode sheets 105 on the insulating flexible film 103.

[0051] It is worth mentioning that in the present application, both the positive electrode active material layer 1042 and the negative electrode active material layer 1052 can be formed on the corresponding current collector by coating. In addition, the present embodiment does not limit the formation order of the positive electrode active material layer 1042 and the negative electrode active material layer 1052.

[0052] Reference Figure 3d , Figure 3d for Figure 3c A top view of the structure shown, which is used to show the Figure 3c The arrangement of the positive electrode sheet 104 and the negative electrode sheet 105 on one surface of the insulating flexible film 103 after the steps shown. Figure 3d It can be seen that in the embodiment of the present application, the width W1 of the negative current collector 1051 can be made greater than the width W3 of the negative active material layer 1052, so that in the width direction, one end of the negative current collector 1051 not covered by the negative active material layer 1052 can be used as a negative electrode ear 102, and the negative electrode ear 102 can be used to electrically connect to the negative electrode column of the battery. Similarly, the width W2 of the positive current collector 1041 is also greater than the width W4 of the positive active material layer 1042, so that in the width direction, one end of the positive current collector 1041 not covered by the positive active material layer 1042 can be used as a positive electrode ear 101, and the positive electrode ear 101 can be used to electrically connect to the positive electrode column of the battery. With such a design, the structure of the battery cell 1 can be effectively simplified.

[0053] In some possible embodiments of the present application, the positive electrode ear 101 and the negative electrode ear 102 of the battery cell 1 can also be arranged separately, so that the positive electrode ear 101 can be electrically connected to the positive electrode collector 1041 by welding or the like, and the negative electrode ear 102 can be electrically connected to the negative electrode collector 1051 by welding or the like, so as to improve the setting flexibility of the positive electrode ear 101 and the negative electrode ear 102.

[0054] Reference Figure 3e , Figure 3e Shown in Figure 3c Schematic diagram of the structure formed after the separator 106 is covered on the structure shown in FIG. In this embodiment, the battery cell 1 includes only one separator 106. Figure 3e Based on the structure shown in FIG. 1 , the winding process can be used to wind it clockwise along the X direction to obtain Figure 2 The battery cell 1 shown. It can be understood that the X direction mentioned above can also be understood as the winding direction of the battery cell 1.

[0055] You can continue to refer to Figure 3e In addition to the area for setting the positive electrode sheet 104 and the negative electrode sheet 105, the insulating flexible film 103 also has an area between any two adjacent electrode sheets where no electrode sheet is set. In the embodiment of the present application, for ease of description, the area of ​​the insulating flexible film 103 for setting the positive electrode sheet 104 and the negative electrode sheet 105 can be defined as an electrode sheet setting area 1031, and the area of ​​the insulating flexible film 103 between any two electrode sheet setting areas 1031 can be defined as a non-electrode sheet setting area 1032. Then in Figure 3e In the structure shown, the insulating flexible film 103 includes 2N+1 pole piece setting areas 1031 and 2N non-pole piece setting areas 1032, wherein each non-pole piece setting area 1032 is located between two adjacent pole piece setting areas 1031, and the 2N+1 pole piece setting areas 1031 and the 2N non-pole piece setting areas 1032 are arranged alternately. In this way, the N groups of positive electrode sheets 104 and the N+1 groups of negative electrode sheets 105 of the battery cell 1 can be arranged one by one in the 2N+1 electrode sheet setting areas 1031, and along the X direction, that is, the arrangement direction of the 2N+1 electrode sheet setting areas 1031 and the 2N non-pole sheet setting areas 1032, the length of the non-pole sheet setting area 1032 is greater than or equal to 1.3×n×(Ta+Tc+Ts), wherein Ta is the thickness of each negative electrode sheet 105, Tc is the thickness of each positive electrode sheet 104, Ts is the thickness of the diaphragm 106, n is the order of the non-pole sheet setting area 1032 starting from the center of the battery cell 1, and n is an integer greater than or equal to 1.

[0056] Can refer to Figure 2 and Figure 3eIn the battery cell 1 formed by the winding process in the above embodiment of the present application, N groups of positive electrode sheets 104 and N+1 groups of negative electrode sheets 105 are arranged alternately along the stacking direction, and the non-electrode sheet setting area 1032 of the insulating flexible film 103 is located at the corner of the battery cell 1. This can effectively reduce the risk of ion precipitation and fracture of the battery cell 1 during the expansion of the electrode sheet, thereby improving the reliability of the structure of the battery cell 1 and the charging and discharging performance.

[0057] In a specific embodiment of the present application, there is provided a method for applying the above Figures 3a to 3e The sodium battery cell prepared by the steps shown. In the cell, the positive current collector 1041 of the positive electrode sheet 104 and the negative current collector 1051 of the negative electrode sheet 105 are both aluminum sheets, wherein the width of the positive current collector 1041 is 103 mm and the length is 154 mm, and the width of the negative current collector 1051 is 105 mm and the length is 156 mm. In addition, the width of the positive active material layer 1042 is 98 mm, the length of the positive active material layer 1042 is 154 mm, the width of the negative active material layer 1052 is 100 mm, and the length of the negative active material layer 1052 is 156 mm. And in the cell 1, the total thickness of the positive electrode sheet 104 is 120 um, the total thickness of the negative electrode sheet 105 is 200 um, and the thickness of the separator 106 is 15 um. In addition, the length of the first non-pole sheet setting area 1032 starting from the center of the cell 1 can be set to 2 mm. The positive electrode sheet 104 of the battery cell 1 has 66 layers, and the negative electrode sheet 105 has 67 layers. The battery cell 1 has a large number of electrode sheets, which is beneficial to improving the energy density of the battery.

[0058] In addition, the preparation method of the battery cell 1 provided in the above embodiment can also be used to prepare battery cells 1 of other types of batteries. For example, the positive electrode current collector 1041 is set as an aluminum sheet, and the negative electrode current collector 1051 is set as a copper sheet to prepare a battery cell 1 of a lithium battery 10, etc. Each type of battery cell 1 is not introduced one by one here, but they should all be understood to fall within the scope of protection of this application.

[0059] Reference Figure 4 , Figure 4 Another schematic diagram of the structure of the battery cell 1 of the battery 10 provided in the embodiment of the present application. Figure 2 The battery cell 1 shown is different in that Figure 4 The battery cell 1 shown is a serpentine bending structure, or can be understood as an S-shaped bending structure. Figure 4 The battery cell 1 shown can be prepared by a lamination process, but is different from the battery cell 1 of a conventional lamination structure in that: Figure 4The positive electrode sheet 104 and the negative electrode sheet 105 of the battery cell 1 are formed on the same insulating flexible film 103. When N groups of positive electrode sheets 104 and N+1 groups of negative electrode sheets 105 are stacked to form the battery cell 1, there is no need to cut the positive electrode sheet 104 and the negative electrode sheet 105, which can effectively reduce the probability of burrs, thereby improving the product yield and production efficiency of the battery cell 1 and reducing processing costs.

[0060] In addition, in order to avoid short circuit between the positive electrode sheet 104 and the negative electrode sheet 105 adjacent to each other in the stacking direction, Figure 4 The battery cell 1 shown includes 2N+2 separators 106 , wherein along the stacking direction, each group of positive electrode sheets 104 is located between two separators 106 , and each group of negative electrode sheets 105 is located between two separators 106 .

[0061] You can continue to refer to Figure 4 In the battery cell 1 , the insulating flexible film 103 also includes 2N+1 pole piece setting areas 1031 and 2N non-pole piece setting areas 1032 , and the 2N+1 pole piece setting areas 1031 and the 2N non-pole piece setting areas 1032 are alternately arranged.

[0062] Understandably, Figure 4 The preparation process of the battery cell 1 shown is similar to the above Figure 2 The preparation process of the battery cell shown in is similar and will not be described in detail here, but it should be noted that the preparation Figure 4 When the battery cell 1 is shown, Figure 3a In the steps shown, the arrangement order of N groups of positive current collectors 1041 and N+1 groups of negative current collectors 1051 formed on the insulating flexible film 103 can be: negative current collector 1051-positive current collector 1041-negative current collector 1051-…positive current collector 1041-negative current collector 1051, that is, N groups of positive current collectors 1041 and N+1 groups of negative current collectors 1051 are arranged alternately in sequence.

[0063] In addition, along the arrangement direction of the 2N+1 pole piece setting areas 1031 and the 2N non-pole piece setting areas 1032, the length of each non-pole piece setting area 1032 is equal, and the length of each non-pole piece setting area 1032 can be greater than or equal to 1.3×(Ta+Tc+Ts), where Ta is the thickness of each negative pole piece 105 along the stacking direction, Tc is the thickness of each positive pole piece 104 along the stacking direction, and Ts is the thickness of each separator 106 along the stacking direction. In this way, the non-pole piece area of ​​the insulating flexible film 103 can be located at the corner of the battery cell 1, which can effectively reduce the risk of ion precipitation and fracture of the battery cell 1 during the expansion of the pole piece, thereby improving the reliability of the structure and charge and discharge performance of the battery cell 1.

[0064] in addition, Figure 4 The other structures of the battery cell 1 shown can all refer to the above embodiments, and will not be described in detail here.

[0065] In the battery 10 provided in the embodiment of the present application, the N groups of positive pole pieces 104 and the N+1 groups of negative pole pieces 105 of the battery cell 1 are all arranged on the same insulating flexible film 103, and the battery cell 1 can be obtained by using the existing winding process and lamination process, which makes the N groups of positive pole pieces 104 and the N+1 groups of negative pole pieces 105 alternately arranged along the stacking direction to improve the energy density of the battery cell 1, and can also reduce the risk of fracture and ion precipitation of the battery cell 1 by making the non-pole piece setting area 1032 of the insulating flexible film 103 located at the corner of the battery cell 1, so as to effectively improve the reliability of the structure and charge and discharge performance of the battery cell 1. In addition, since the preparation of the positive pole piece 104 and the negative pole piece 105 does not involve the cutting process in the process of obtaining the battery cell 1 by the lamination process, it can effectively reduce the probability of burr generation, thereby improving the product yield and production efficiency of the battery cell 1, and reducing the processing cost.

[0066] The battery 10 provided in the embodiment of the present application can be applied to the energy storage system. In actual application, according to the different power requirements in different application scenarios, any two batteries 10 in the plurality of batteries 10 are usually connected in series or in parallel to form a battery pack for application in the energy storage system to provide appropriate voltage, capacity and power. In addition, the energy storage system may also include an energy storage inverter and an energy storage cabinet. Figure 5 , Figure 5 A schematic diagram of the structure of an energy storage cabinet 200 provided in an embodiment of the present application. The energy storage cabinet 200 includes one or more battery packs 100 composed of the batteries 10 provided in the above-mentioned embodiment. In addition, an energy storage inverter can be electrically connected to the battery pack 100 of the energy storage cabinet 200, and the energy storage inverter is used to convert the AC power output by an external power source into DC power and then provide it to the battery pack 100, or convert the DC power from the battery pack 100 into AC power and output it to an external device. Since the battery provided in the embodiment of the present application has a high energy density and production efficiency, and its structure and the reliability of the charge and discharge performance are better, it can be beneficial to reduce the cost of the energy storage system and improve the operational reliability of the energy storage system.

[0067] In addition, the energy storage system may also include a battery management system, which can effectively detect parameters such as the temperature, state of charge, and health status of the battery pack 100 in the energy storage cabinet 200, and can also effectively regulate the charging and discharging functions of the battery pack 100, thereby ensuring the normal operation of the energy storage system.

[0068] The battery 10 provided in the above embodiment of the present application can also be applied to a power supply system. In addition, the power supply system can also include a power generation device. The power generation device is electrically connected to the battery, and the power generation device can be used to store the electric energy generated by it in the battery. By applying the above battery 10, the cost of the power supply system can be effectively reduced.

[0069] In a specific embodiment, the power supply system may be a large power station or a micro power station, wherein the micro power station may be located in an industrial park or a community. Alternatively, the power supply system may also be a household power supply system or a power supply system for equipment such as a vehicle.

[0070] The power generation equipment can be, but is not limited to, photovoltaic power generation equipment, wind power generation equipment, etc., and the embodiments of the present application do not limit the specific type of the power generation equipment. In addition, in practical applications, the power generation equipment and the battery 10 can also be connected through a distribution cabinet. The distribution cabinet may include a DC-AC conversion device, or may also include devices such as a transformer, so as to effectively transmit the electric energy generated by the power generation equipment to the battery 10 for storage. In the specific setting, the number and type of devices in the distribution cabinet can be reasonably set according to actual needs, and the embodiments of the present application do not limit this.

[0071] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A battery, characterized in that: The invention comprises a battery cell, wherein the battery cell comprises an insulating flexible film, N groups of positive electrode sheets and N+1 groups of negative electrode sheets, wherein: Each group of the positive electrode sheets comprises two positive electrode sheets, the two positive electrode sheets are respectively located on two surfaces of the insulating flexible film, and the two positive electrode sheets are arranged back to back; Each group of the negative electrode sheets comprises two negative electrode sheets, the two negative electrode sheets are respectively located on two surfaces of the insulating flexible film, and the two negative electrode sheets are arranged back to back; The N groups of positive electrode sheets and the N+1 groups of negative electrode sheets are stacked, and each group of positive electrode sheets is located between two adjacent groups of negative electrode sheets along the stacking direction; N is an integer greater than or equal to 1.

2. The battery according to claim 1, characterized in that The battery cell is a winding structure, and the battery further includes a separator, and along the stacking direction, the separator covers each of the positive electrode sheets and each of the negative electrode sheets.

3. The battery according to claim 2, characterized in that The insulating flexible film includes 2N+1 pole piece setting areas and 2N non-pole piece setting areas, each of the non-pole piece setting areas is located between two adjacent pole piece setting areas, and the N groups of positive pole pieces and the N+1 groups of negative pole pieces are arranged in the 2N+1 pole piece setting areas in a one-to-one correspondence; Along the arrangement direction of the 2N+1 pole piece setting areas and the 2N non-pole piece setting areas, the length of the non-pole piece setting areas is greater than or equal to 1.3×n×(Ta+Tc+Ts), wherein Ta is the thickness of each of the negative pole pieces along the stacking direction, Tc is the thickness of each of the positive pole pieces along the stacking direction, Ts is the thickness of the diaphragm along the stacking direction, n is the order of the non-pole piece setting areas starting from the center of the battery cell, and n is an integer greater than or equal to 1.

4. The battery according to claim 1, characterized in that The battery cell has a serpentine bending structure, and the battery further includes 2N+2 separators. Along the stacking direction, each group of negative electrode plates is located between two separators, and each group of positive electrode plates is located between two separators.

5. The battery according to claim 4, characterized in that The insulating flexible film includes 2N+1 pole piece setting areas and 2N non-pole piece setting areas, each of the non-pole piece setting areas is located between two adjacent pole piece setting areas, and the N groups of positive pole pieces and the N+1 groups of negative pole pieces are arranged in the 2N+1 pole piece setting areas in a one-to-one correspondence; Along the arrangement direction of the 2N+1 pole piece setting areas and the 2N non-pole piece setting areas, the length of each of the non-pole piece setting areas is greater than or equal to 1.3×(Ta+Tc+Ts), wherein Ta is the thickness of each of the negative pole pieces along the stacking direction, Tc is the thickness of each of the positive pole pieces along the stacking direction, and Ts is the thickness of each of the diaphragms along the stacking direction.

6. The battery according to claim 3 or 5, characterized in that Each of the negative electrode sheets comprises a negative electrode current collector and a negative electrode active material, wherein the negative electrode current collector is arranged on the surface of the insulating flexible film, and the negative electrode active material is arranged on the surface of the negative electrode current collector away from the insulating flexible film; Each of the positive electrode sheets comprises a positive current collector and a positive active material layer. The positive current collector is arranged on the surface of the insulating flexible film, and the positive active material is arranged on the surface of the positive current collector away from the insulating flexible film.

7. The battery according to claim 6, characterized in that The length of the negative electrode current collector is 100 mm to 1000 mm; the length of the positive electrode current collector is 1 mm to 100 mm shorter than that of the negative electrode current collector.

8. The battery according to claim 7, characterized in that The width of the negative electrode current collector is 50 mm to 600 mm, and the width of the positive electrode current collector is 1 mm to 50 mm smaller than the width of the negative electrode current collector, wherein the width direction is perpendicular to the length direction.

9. The battery according to any one of claims 6 to 8, characterized in that: The battery cell further includes a negative electrode ear and a positive electrode ear, wherein the negative electrode ear is electrically connected to the negative electrode collector, and the positive electrode ear is electrically connected to the positive electrode collector.

10. The battery according to claim 9, characterized in that The width of the negative electrode active material layer is smaller than the width of the negative electrode current collector, and one end of the negative electrode current collector not covered by the negative electrode active material layer in the width direction serves as a negative electrode ear; The width of the positive electrode active material layer is smaller than the width of the positive electrode current collector, and one end of the positive electrode current collector not covered by the positive electrode active material layer in the width direction serves as a negative electrode tab.

11. The battery according to claim 9 or 10, characterized in that The battery further comprises a battery shell and a cover plate, the battery cell is accommodated in the battery shell, and the cover plate is covered on the battery shell; the cover plate comprises a positive electrode column and a negative electrode column, the positive electrode column is electrically connected to the positive electrode ear, and the negative electrode column is electrically connected to the negative electrode ear.

12. The battery according to any one of claims 6 to 11, characterized in that: The negative electrode current collector is made of copper or aluminum; the positive electrode current collector is made of aluminum.

13. The battery according to any one of claims 1 to 12, characterized in that: The insulating flexible film is made of one of polyamide, polyethylene terephthalate, polytetrafluoroethylene, polyvinylidene fluoride, polyimide, polyethylene, polypropylene, polystyrene, polyvinyl chloride or polypropylene.

14. A battery pack, characterized in that: The method comprises a plurality of batteries according to any one of claims 1 to 13, wherein any two of the plurality of batteries are connected in series or in parallel.

15. An energy storage system, characterized in that: It comprises an energy storage inverter and an energy storage cabinet, wherein the energy storage cabinet comprises one or more battery packs as claimed in claim 14, and the energy storage inverter is electrically connected to the energy storage cabinet, and is used to convert the alternating current output by an external power source into direct current and then provide it to the energy storage cabinet, or to convert the direct current from the energy storage cabinet into alternating current and output it to an external device.

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