Secondary battery, preparation method and device thereof, energy storage system and electric equipment

Abstract

The invention relates to a secondary battery and a preparation method and device thereof, an energy storage system and electric equipment. The preparation method of the secondary battery comprises the following steps: preparing an electrode assembly from a positive plate, an isolating membrane and a negative plate, and packaging the electrode assembly to form a battery cell; putting the battery cell into a baking cavity; the battery cell is heated, and the baking cavity is vacuumized; under the condition that the real-time vacuum value in the baking cavity reaches a preset vacuum value, the battery cell is continuously heated, and the baking cavity is filled with auxiliary gas; wherein the auxiliary gas is dry inert gas with positive pressure; under the condition that the real-time temperature of the battery cell reaches the preset preheating temperature, filling of the auxiliary gas into the baking cavity is stopped; and taking out the battery cell from the baking cavity, and injecting liquid into the battery cell to obtain the secondary battery. According to the preparation method of the secondary battery, under synergistic heating of multiple heat transfer modes, the temperature rising speed of the battery cell is effectively increased, the preheating time of the battery cell is shortened, and the heating power of the heating assembly can be reduced so as to save electric energy.

Description

Technical Field

[0001] The present application relates to the field of battery manufacturing technology, and in particular to a secondary battery and a preparation method and device thereof, an energy storage system, and electrical equipment. Background Art

[0002] Battery cells are an important part of modern high-tech products, and their performance is directly related to the service life and safety of the battery. When producing battery cells, the drying process is an indispensable step. Battery cells need to continuously add liquid raw materials during the production process, and these raw materials contain a lot of water. After the battery cell is assembled, if the next step is carried out directly, the moisture inside the battery cell will cause the battery cell to leak electricity, be damaged or even explode easily, so the battery cell must be dried.

[0003] However, due to technical defects in the current battery cell baking process, the temperature rise rate inside the battery cell is slow and the preheating time is long, which causes the entire baking process to take too long, thereby affecting the battery production efficiency. Summary of the invention

[0004] Based on this, it is necessary to provide a secondary battery and its preparation method and device, energy storage system, and electrical equipment to address the problem that the baking process of the battery cell takes too long.

[0005] A method for preparing a secondary battery comprises the following steps:

[0006] The positive electrode sheet, the separator and the negative electrode sheet are manufactured into an electrode assembly, and the electrode assembly is packaged to form a battery cell;

[0007] placing the battery cell into a baking chamber;

[0008] heating the battery core and evacuating the baking chamber;

[0009] When the real-time vacuum value in the baking chamber reaches a preset vacuum value, the battery cell is continuously heated and an auxiliary gas is filled into the baking chamber; wherein the auxiliary gas is a dry inert gas with a positive pressure;

[0010] When the real-time temperature of the battery cell reaches a preset preheating temperature, stopping filling the auxiliary gas into the baking chamber;

[0011] Taking out the battery cell from the baking chamber and injecting liquid into the battery cell to obtain a secondary battery;

[0012] While continuing to heat the battery cell and filling the baking chamber with auxiliary gas, the following steps are also included:

[0013] Recovering the auxiliary gas in the baking chamber to a recovery chamber;

[0014] The auxiliary gas recovered by the recovery chamber is dried and thermally managed to form dry auxiliary gas with different temperatures, wherein a part of the auxiliary gas releases heat to form a normal temperature state, and another part of the auxiliary gas absorbs heat to form a high temperature state.

[0015] In one embodiment, when the real-time temperature of the battery cell reaches a preset preheating temperature, after the step of stopping the filling of the auxiliary gas into the baking chamber, the following steps are also included:

[0016] evacuating the baking chamber;

[0017] The auxiliary gas extracted from the baking chamber is recovered to the recovery chamber.

[0018] In one embodiment, after the step of recovering the auxiliary gas extracted from the baking chamber to the recovery chamber, the following steps are further included:

[0019] When the heating time reaches a preset heating time, the heating of the battery cell is stopped, and the baking chamber is vented;

[0020] Filling the auxiliary gas at room temperature into the baking chamber;

[0021] When the real-time temperature of the battery cell reaches a preset cooling temperature, the auxiliary gas is stopped from being filled into the baking chamber.

[0022] In one embodiment, while the step of filling the auxiliary gas at room temperature into the baking chamber, the following steps are also included:

[0023] Recovering the auxiliary gas in the baking chamber to the recovery chamber;

[0024] The auxiliary gas recovered by the recovery chamber is dried and thermally managed to form dry auxiliary gas with different temperatures, wherein a part of the auxiliary gas releases heat to form a normal temperature state, and another part of the auxiliary gas absorbs heat to form a high temperature state.

[0025] In one embodiment, when the real-time temperature of the battery cell reaches a preset cooling temperature, after the step of stopping the filling of the auxiliary gas into the baking chamber, the following steps are also included:

[0026] Extracting the auxiliary gas in the baking chamber and recycling it into the recovery chamber;

[0027] The baking chamber is evacuated by using external ambient gas.

[0028] In one of the embodiments, the battery cell is accommodated in a receiving cavity, and the real-time temperature of the battery cell is the top temperature of at least one of the battery cells located in four vertex corner areas of the receiving cavity.

[0029] In one embodiment, before the step of forming the electrode assembly from the positive electrode sheet, the separator and the negative electrode sheet, the method further comprises:

[0030] The positive electrode slurry is applied to the positive electrode current collector and dried to obtain the positive electrode sheet, and the negative electrode slurry is applied to the negative electrode current collector and dried to obtain the negative electrode sheet;

[0031] After the step of injecting liquid into the battery cell, the method further comprises:

[0032] Performing a formation treatment on the battery cell;

[0033] The step of thermally managing the auxiliary gas further comprises:

[0034] Obtaining heat from the auxiliary gas through a heat exchange medium;

[0035] In the target processing step, heat is exchanged using the heat exchange medium after the heat is obtained;

[0036] The target processing step includes at least one of a step of drying the positive electrode sheet, a step of drying the negative electrode sheet, and a step of performing a formation treatment on the battery cell.

[0037] A secondary battery preparation device is applied to the secondary battery preparation method, and the secondary battery preparation device comprises:

[0038] A baking oven, comprising a baking chamber and an air inlet and an air outlet respectively connected to the baking chamber;

[0039] A heating component is disposed in the baking cavity, the heating component has a receiving cavity with one end open, and the heating component is used to receive and heat the battery core;

[0040] an air intake mechanism, connected to the baking oven through the air intake port, the air intake mechanism being used to fill the baking cavity with gas; and

[0041] An exhaust mechanism is connected to the baking oven through the exhaust port, and the exhaust mechanism is used to extract the gas in the baking chamber.

[0042] In one embodiment, the secondary battery preparation device also includes a drying mechanism and a heat exchange mechanism, the drying mechanism is connected between the exhaust mechanism and the heat exchange mechanism, the drying mechanism is used to dry the gas, the heat exchange mechanism is connected between the drying mechanism and the air intake mechanism, and the heat exchange mechanism is used to perform heat exchange.

[0043] In one embodiment, the air intake mechanism comprises:

[0044] a first air inlet pipeline, wherein the air inlet end of the first air inlet pipeline is used to connect to an external air supply device, the air outlet end of the first air inlet pipeline is connected to the baking oven through the air inlet, and the first air inlet pipeline is used to transport gas;

[0045] a second air inlet pipeline, wherein an air inlet end of the second air inlet pipeline is connected to the heat exchange mechanism, an air outlet end of the second air inlet pipeline is connected to the baking oven through the air inlet, and the second air inlet pipeline is used to store and transport room temperature gas; and

[0046] A third air inlet pipeline, the air inlet end of the third air inlet pipeline is connected to the heat exchange mechanism, the air outlet end of the third air inlet pipeline is connected to the baking oven through the air inlet, and the third air inlet pipeline is used to store and transport high-temperature gas.

[0047] In one embodiment, the exhaust mechanism comprises:

[0048] a recovery unit for storing gas;

[0049] a first exhaust pipeline, wherein an air inlet end of the first exhaust pipeline is connected to the baking oven through the exhaust port, an air outlet end of the first exhaust pipeline is connected to the recovery unit, and the first exhaust pipeline is used to transport gas;

[0050] a second exhaust pipeline, wherein an air inlet end of the second exhaust pipeline is connected to the baking oven through the exhaust port, an air outlet end of the second exhaust pipeline is connected to the recovery unit, a pressurizing unit is provided in the second exhaust pipeline, and the second exhaust pipeline is used to transport gas; and

[0051] The third exhaust pipeline, the air inlet end of the third exhaust pipeline is connected to the baking oven through the exhaust port, the air outlet end of the third exhaust pipeline is connected to the recovery unit, the third exhaust pipeline is provided with a vacuum unit, and the third exhaust pipeline is used to transport gas.

[0052] In one embodiment, the heating component further includes at least one temperature detection module, which is installed at the open end of the accommodating cavity, and the temperature detection module is used to detect the top temperature of at least one of the battery cells located in the four top corner areas of the accommodating cavity.

[0053] A secondary battery is prepared by the secondary battery preparation device and the secondary battery preparation method.

[0054] An energy storage system comprises the above-mentioned secondary battery.

[0055] An electrical device comprises the above energy storage system.

[0056] The above-mentioned secondary battery preparation method, in addition to utilizing the heating component to realize heat conduction heating and real-time heat radiation heating, also introduces dry inert gas with positive pressure into the baking chamber during the preheating process to form thermal convection heating. Under the coordinated heating of multiple heat transfer methods, not only the heating rate of the battery cell is effectively improved and the preheating time of the battery cell is shortened, but also the heating power of the heating component can be reduced to save electricity. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0058] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0059] Figure 1 This is a pipeline connection diagram of a secondary battery preparation device according to an embodiment of the present application.

[0060] Figure 2 It is a structural schematic diagram of a baking furnace of a secondary battery preparation device according to an embodiment of the present application.

[0061] Figure 3 for Figure 2 A schematic diagram of the structure of the baking oven shown in another direction.

[0062] Figure 4 for Figure 1 A schematic structural diagram of a heating assembly of a secondary battery preparation device is shown.

[0063] Figure 5 for Figure 2 A schematic structural diagram of a furnace body of a baking furnace is shown.

[0064] Figure 6 for Figure 5 A partial enlarged view of the furnace body is shown.

[0065] Figure 7 for Figure 4 A schematic diagram of the heating assembly shown containing a battery cell.

[0066] Figure 8 for Figure 7 A partial enlarged schematic diagram of the heating component shown.

[0067] Fig. 9 for Figure 1 The pipe connection diagram of the air intake mechanism of the secondary battery preparation device shown.

[0068] Fig.10 for Figure 1 The pipe connection diagram of the exhaust mechanism of the secondary battery preparation device is shown.

[0069] Fig.11 Flow chart of a secondary battery preparation method according to an embodiment of the present application.

[0070] Description of reference numerals:

[0071] 100, secondary battery preparation device; 110, baking furnace; 110a, baking chamber; 110b, air inlet; 110c, exhaust port; 112, furnace body; 1121, reinforcing rib; 114, furnace door; 116, driving mechanism; 118, sealing ring; 120, heating assembly; 120a, accommodating chamber; 121, heating bottom plate; 123, heating side plate; 125, temperature detection module; 130, air intake mechanism; 132, first air intake pipeline; 1321, first regulating valve; 134, second air intake pipeline; 1341, first booster pump; 1343, second regulating valve; 1345, first storage chamber; 1347, third regulating valve; 1 36. third air intake pipeline; 1361. second boost pump; 1363. fourth regulating valve; 1365. second storage chamber; 1367. fifth regulating valve; 140. exhaust mechanism; 141. recovery unit; 143. first exhaust pipeline; 1432. sixth regulating valve; 145. second exhaust pipeline; 1452. seventh regulating valve; 1454. boost unit; 1456. eighth regulating valve; 147. third exhaust pipeline; 1472. ninth regulating valve; 1474. vacuum unit; 1476. tenth regulating valve; 149. fourth exhaust pipeline; 1392. eleventh regulating valve; 150. drying mechanism; 160. heat exchange mechanism;

[0072] 200. Battery cells. DETAILED DESCRIPTION

[0073] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0074] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0075] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0076] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0077] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0078] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0079] See also Figures 1 to 4 The embodiment of the present application provides a secondary battery preparation device 100, which is used in a secondary battery production line to bake a battery cell 200 to remove moisture in the battery cell 200. The secondary battery may be, but is not limited to, an alkali metal secondary battery such as a lithium secondary battery, a sodium secondary battery, or an aluminum secondary battery.

[0080] In some embodiments, the production line of secondary batteries also includes other devices for producing secondary batteries. The upstream of the secondary battery preparation device 100 may be provided with a coating device for making positive electrode sheets and negative electrode sheets, a winding (or lamination) device for forming electrode assemblies from positive electrode sheets and negative electrode sheets, a steam drying device for drying electrode assemblies, a packaging device for packaging electrode assemblies, etc.; the downstream of the secondary battery preparation device 100 may be provided with a high-temperature standing device for forming the battery cell 200, a liquid injection device for injecting liquid into the battery cell 200, etc.

[0081] See also Figure 1 , Figure 4 as well as Figure 5 The secondary battery preparation device 100 includes a baking oven 110 , a heating assembly 120 , an air intake mechanism 130 and an exhaust mechanism 140 .

[0082] The baking oven 110 has a baking chamber 110a, an air inlet 110b and an exhaust port 110c. The air inlet 110b and the exhaust port 110c are respectively connected to the baking chamber 110a. The baking chamber 110a is used to accommodate the heating component 120. External gas can enter the baking chamber 110a through the air inlet 110b, and the gas in the baking chamber 110a can flow out through the exhaust port 110c. The heating component 120 is arranged in the baking oven 110. The heating component 120 has a accommodating chamber 120a with one end open. The heating component 120 is used to accommodate and heat the battery cell 200. The air intake mechanism 130 is connected to the baking oven 110 through the air inlet 110b, and is used to fill the baking chamber 110a with gas. The exhaust mechanism 140 is connected to the baking oven 110 through the exhaust port 110c, and is used to extract the gas in the baking chamber 110a.

[0083] In the process of baking the battery cell 200, the secondary battery preparation device 100 can heat the battery cell 200 by heat conduction and heat radiation through the heating component 120, and on the other hand, fill the baking chamber 110a with gas (for example, dry inert gas with positive pressure) through the air intake mechanism 130 to form thermal convection heating. Under the synergistic effect of multiple heat transfer methods, the heating speed of the battery cell 200 is effectively improved, and the preheating time of the battery cell 200 is shortened. In addition, the exhaust mechanism 140 can be used to recover the gas in the baking chamber 110a, thereby realizing efficient recovery and recycling of gas and heat, effectively reducing heat loss, and significantly reducing the production cost of secondary batteries.

[0084] In some embodiments, the secondary battery preparation device 100 also includes a drying mechanism 150 and a heat exchange mechanism 160. The drying mechanism 150 is connected between the exhaust mechanism 140 and the heat exchange mechanism 160. The drying mechanism 150 is used to dry the gas. The heat exchange mechanism 160 is connected between the drying mechanism 150 and the air intake mechanism 130. The heat exchange mechanism 160 is used to perform heat exchange.

[0085] In this way, the gas extracted by the exhaust mechanism 140 can be dried by the drying mechanism 150, and then enter the heat exchange mechanism 160 for heat exchange, a part of the gas can release heat to form a normal temperature state, and the other part of the gas can absorb heat to form a high temperature state, and the gases with different temperatures can enter the baking chamber 110a again through the air intake mechanism 130, thereby providing the baking chamber 110a with gases with different temperatures. Moreover, the excess heat obtained from the gas by the heat exchange mechanism 160 can be transported to at least one of the upstream device and the downstream device of the secondary battery preparation device 100 through the heat exchange medium, thereby achieving full utilization of energy.

[0086] like Figure 2 , Figure 3 as well as Figure 5 As shown, the baking oven 110 includes an oven body 112 and an oven door 114. The oven body 112 is a cubic hollow structure with one end open, and the oven door 114 is installed at the open end of the oven body 112 in an openable manner. The oven door 114 and the oven body 112 together define a baking chamber 110a, and the baking chamber 110a can be opened or closed by opening and closing the oven door 114. It can be understood that the shape and size of the baking oven 110 are not limited, and can be set as needed to meet different baking requirements.

[0087] In some embodiments, a plurality of reinforcing ribs 1121 are convexly provided on the outer surface of the furnace body 112, and the reinforcing ribs 1121 are used to increase the structural strength of the furnace body 112, thereby preventing the furnace body 112 from deforming when the internal pressure changes. Specifically in one embodiment, the reinforcing ribs 1121 are in the form of long strips, and the reinforcing ribs 1121 located on the top wall and the bottom wall of the furnace body 112 are arranged at intervals along the length direction of the furnace body 112, and each reinforcing rib 1121 extends along the width direction of the furnace body 112, and the reinforcing ribs 1121 located on the side wall of the furnace body 112 are arranged at intervals along the length direction of the furnace body 112, and each reinforcing rib 1121 extends along the height direction of the furnace body 112. It can be understood that the number, shape, and setting position of the reinforcing ribs 1121 are not limited, and can be set as needed to meet different strength requirements.

[0088] Furthermore, the baking oven 110 also includes a driving mechanism 116, which is installed on the oven body 112 and is transmission-connected to the oven door 114. The driving mechanism 116 can drive the oven door 114 to rotate relative to the oven body 112 and apply a certain pressure to the oven door 114 so that the oven door 114 seals the oven body 112, thereby ensuring the sealing of the baking oven 110.

[0089] Specifically in one embodiment, the driving mechanism 116 may include a cylinder or a servo motor. Compared with the cylinder, the servo motor can provide greater pressure to control the oven door 114 to be pressed into place, thereby further improving the sealing of the baking oven 110 and effectively preventing the heat in the baking chamber 110a from being lost. It can be understood that the specific structure of the driving mechanism 116 is not limited and can be set as needed to meet different requirements for opening and closing the oven door 114.

[0090] Furthermore, please combine Figure 5 , Figure 6 As shown, the baking oven 110 further includes a sealing ring 118 , which is an annular structure and is circumferentially arranged around the open end of the oven body 112 to further seal the gap between the oven door 114 and the oven body 112 to further ensure the sealing of the baking oven 110 .

[0091] As a preferred embodiment, the sealing ring 118 is an inflatable sealing ring. When the oven door 114 is closed, compressed gas can be filled into the sealing ring 118 to expand it. The expanded sealing ring 118 can fit tightly with the oven door 114 and the oven body 112, thereby having a better sealing effect and preventing the heat in the baking chamber 110a from being lost. In some other embodiments, the sealing ring 118 is also formed of a material that can undergo elastic deformation, such as rubber, so as to also have a good sealing effect.

[0092] In some embodiments, the baking oven 110 is designed, manufactured, inspected and maintained in accordance with the requirements of a pressure vessel. As a preferred embodiment, a safety pressure relief valve is also installed on the furnace body 112 of the baking oven 110. The safety pressure relief valve is used to automatically release pressure when the air pressure in the baking chamber 110a is too high, thereby avoiding excessive pressure in the baking chamber 110a, which may cause damage to the baking oven 110 and other equipment or a safety accident.

[0093] like Figure 4 , Figure 7 as well as Figure 8 As shown, a plurality of heating components 120 may be stacked in the vertical direction in the baking chamber 110a. Each heating component 120 is a cubic shell structure with one side open, including a heating bottom plate 121 and a heating side plate 123. The heating bottom plate 121 is a rectangular flat plate structure. The heating side plate 123 surrounds the heating bottom plate 121 in the circumferential direction to form a receiving chamber 120a with one end open. The heating bottom plate 121 may generate heat to heat the battery cell 200. In this way, the plurality of battery cells 200 may be at least partially received in the receiving chamber 120a and arranged in an array. The heating bottom plate 121 is in direct contact with the bottom of the battery cell 200 to heat the battery cell 200.

[0094] In some embodiments, each heating assembly 120 also includes at least one temperature detection module 125, which is installed in the accommodating cavity 120a and is used to detect the real-time temperature of the battery cell 200, so that the working state of the secondary battery preparation device 100 can be controlled according to the real-time temperature of the battery cell 200.

[0095] Specifically, in one embodiment, the temperature detection module 125 is a laser temperature sensor, which uses laser technology to perform non-contact temperature measurement on the battery cell 200, and determines the temperature of the battery cell 200 by analyzing the spectrum emitted or reflected by the battery cell 200. It can be understood that the detection principle of the temperature detection module 125 is not limited to this, and can be set as needed to meet different temperature detection requirements.

[0096] It can be understood that since the heat source of the heating component 120 comes from the heating base plate 121, the heat is transferred from the bottom of the battery cell 200 to the top of the battery cell 200, and the heat in the accommodating cavity 120a diffuses from the middle to the surroundings. Therefore, after the heating component 120 heats the battery cell 200 for a period of time, there is a large temperature difference between the bottom and the top of the battery cell 200. For example, when the battery cell 200 with a heating height of 200 mm is heated, when the temperature of the bottom of the battery cell 200 reaches 97°C, the temperature of the top of the battery cell 200 is still at 90°C, and the temperature of the four battery cells 200 located in the four top corner areas of the opening end of the accommodating cavity 120a is the lowest.

[0097] Therefore, as a preferred embodiment, the temperature detection module 125 is used to detect the top temperature of at least one of the battery cells 200 located in the four vertex corner regions of the opening end of the accommodating cavity 120 a.

[0098] Specifically, in one embodiment, each heating assembly 120 includes four temperature detection modules 125, and the four temperature detection modules 125 are respectively located at the four vertex areas of the opening end of the accommodating cavity 120a, so that the top temperature of the battery cell 200 in the four vertex areas of the accommodating cavity 120a can be detected respectively. When the top temperature of the battery cell 200 located in the four vertex areas of the accommodating cavity 120a reaches the preset requirement, the temperature of each part of each battery cell 200 in the entire accommodating cavity 120a can reach the preset requirement.

[0099] In other embodiments, each heating assembly 120 includes only one temperature detection module 125, which is located in an area of ​​the four top corner areas of the open end of the accommodating cavity 120a that is farthest from the air inlet 110b of the baking oven 110, thereby detecting the top temperature of the battery cell 200 that is farthest from the air inlet 110b of the baking oven 110.

[0100] It can be understood that in some other embodiments, the number and location of the temperature detection modules 125 are not limited thereto, and can be set as needed to meet different detection requirements.

[0101] See also Figure 1 and Fig. 9 In some embodiments, the air intake mechanism 130 includes a first air intake pipeline 132, a second air intake pipeline 134 and a third air intake pipeline 136 connected in parallel between the baking oven 110 and the heat exchange mechanism 160. The first air intake pipeline 132, the second air intake pipeline 134 and the third air intake pipeline 136 can be selectively connected to provide gas to the baking oven 110.

[0102] The air inlet end of the first air inlet pipeline 132 is used to connect to an external air supply device, and the air outlet end of the first air inlet pipeline 132 is connected to the baking oven 110 through the air inlet 110b. The first air inlet pipeline 132 is used to transport the gas provided by the external air supply device to the baking chamber 110a. Specifically, a first regulating valve 1321 is provided on the first air inlet pipeline 132 to achieve gas flow regulation of the first air inlet pipeline 132.

[0103] The air inlet end of the second air inlet pipeline 134 is connected to the heat exchange mechanism 160, and the air outlet end of the second air inlet pipeline 134 is connected to the baking oven 110 through the air inlet 110b. The second air inlet pipeline 134 is used to store and transport room temperature gas.

[0104] Specifically, the second air inlet pipeline 134 is provided with a first boosting pump 1341, a second regulating valve 1343, a first storage cavity 1345 and a third regulating valve 1347 in sequence from the air inlet end to the air outlet end. The first boosting pump 1341 is used to compress gas to increase the gas pressure, the first storage cavity 1345 is used to store normal temperature gas, the second regulating valve 1343 is used to achieve gas flow regulation between the first storage cavity 1345 and the first boosting pump 1341, and the third regulating valve 1347 is used to achieve gas flow regulation between the first storage cavity 1345 and the baking cavity 110a.

[0105] The air inlet end of the third air inlet pipeline 136 is connected to the heat exchange mechanism 160 , and the air outlet end of the third air inlet pipeline 136 is connected to the baking oven 110 through the air inlet 110 b . The third air inlet pipeline 136 is used to store and transport high-temperature gas.

[0106] Specifically, the third air inlet pipeline 136 is provided with a second boosting pump 1361, a fourth regulating valve 1363, a second storage cavity 1365 and a fifth regulating valve 1367 in sequence from the air inlet end to the air outlet end. The second boosting pump 1361 is used to compress the gas to increase the gas pressure, the second storage cavity 1365 is used to store high-temperature gas, the fourth regulating valve 1363 is used to achieve gas flow regulation between the second storage cavity 1365 and the second boosting pump 1361, and the fifth regulating valve 1367 is used to achieve gas flow regulation between the second storage cavity 1365 and the baking cavity 110a.

[0107] See also Figure 1 and Fig.10 The exhaust mechanism 140 includes a recovery unit 141, a first exhaust pipeline 143, a second exhaust pipeline 145 and a third exhaust pipeline 147. The first exhaust pipeline 143, the second exhaust pipeline 145 and the third exhaust pipeline 147 are connected in parallel between the baking oven 110 and the recovery unit 141. The recovery unit 141 is connected to the drying mechanism 150. The recovery unit 141 is provided with a recovery chamber for storing gas recovered from the baking chamber 110a.

[0108] The air inlet end of the first exhaust pipeline 143 is connected to the baking oven 110 through the exhaust port 110c, and the air outlet end of the first exhaust pipeline 143 is connected to the recovery unit 141. The first exhaust pipeline 143 is used to directly transport the gas with a higher pressure in the baking chamber 110a to the recovery chamber of the recovery unit 141. Specifically, the first exhaust pipeline 143 includes a sixth regulating valve 1432, and the sixth regulating valve 1432 is used to achieve gas flow regulation between the baking chamber 110a and the recovery chamber.

[0109] The air inlet end of the second exhaust pipeline 145 is connected to the baking oven 110 through the exhaust port 110c, and the air outlet end of the second exhaust pipeline 145 is connected to the recovery unit 141. The second exhaust pipeline 145 is used to transport the gas in the baking chamber 110a to the recovery chamber.

[0110] Specifically, the second exhaust pipeline 145 is provided with a seventh regulating valve 1452, a pressurizing unit 1454, and an eighth regulating valve 1456 in sequence from the inlet end to the outlet end. The pressurizing unit 1454 may include a pressurizing pump, and the pressurizing unit 1454 is used to increase the recovery pressure. When the gas with a lower pressure in the baking chamber 110a cannot be directly discharged through the first exhaust pipeline 143, the second exhaust pipeline 145 may be opened to allow the gas to enter the recovery unit 141 through the second exhaust pipeline 145. The seventh regulating valve 1452 is used to achieve gas flow regulation between the baking chamber 110a and the pressurizing unit 1454, and the eighth regulating valve 1456 is used to achieve gas flow regulation between the pressurizing unit 1454 and the recovery unit 141.

[0111] The air inlet end of the third exhaust pipeline 147 is connected to the baking oven 110 through the exhaust port 110c, and the air outlet end of the third exhaust pipeline 147 is connected to the recovery unit 141. The third exhaust pipeline 147 is used to transport the gas in the baking chamber 110a to the recovery chamber.

[0112] Specifically, the third exhaust pipeline 147 is provided with a ninth regulating valve 1472, a vacuum unit 1474 and a tenth regulating valve 1476 in sequence from the air inlet end to the outlet end. The vacuum unit 1474 includes a vacuum pump for vacuuming the baking chamber 110a in a negative pressure state, and the gas in the baking chamber 110a can be completely discharged through the third exhaust pipeline 147. The ninth regulating valve 1472 is used to achieve gas flow regulation between the baking chamber 110a and the vacuum unit 1474, and the tenth regulating valve 1476 is used to achieve gas flow regulation between the vacuum unit 1474 and the recovery unit 141.

[0113] In some embodiments, the exhaust mechanism 140 further includes a fourth exhaust pipeline 149, one end of which is connected between the vacuum unit 1474 and the tenth regulating valve 1476, and the other end of which is connected to the exhaust end of the plant, so that the gas extracted by vacuum can be discharged through the exhaust end of the plant. Specifically, the fourth exhaust pipeline 149 is provided with an eleventh regulating valve 1392, which is used to adjust the gas flow of the fourth exhaust pipeline 149.

[0114] In the above embodiment, the first regulating valve 1321, the second regulating valve 1343, the third regulating valve 1347, the fourth regulating valve 1363, the fifth regulating valve 1367, the sixth regulating valve 1432, the seventh regulating valve 1452, the eighth regulating valve 1456, the ninth regulating valve 1472, the tenth regulating valve 1476 and the eleventh regulating valve 1392 can all be flapper valves, which control the flow of gas through the flapper inside the valve, and have the characteristics of simple structure, convenient processing, fast response, high precision and sensitivity. In some other embodiments, the above regulating valves can also be other types of valve structures, and the specific types of different regulating valves can be the same or different, which is not limited here.

[0115] The heat exchange mechanism 160 may be a high-temperature heat pump, which is provided with a heat exchange pipe, in which a flowable heat exchange medium (such as water) is provided for heat exchange and transportation.

[0116] In some embodiments, the heat exchange mechanism 160 can obtain heat from part of the recovered gas through a heat exchange medium and further heat another part of the gas, while also transferring excess heat in the gas to upstream and downstream devices of the secondary battery preparation device 100 .

[0117] In other embodiments, the heat exchange mechanism 160 may first obtain heat from all the recovered gases through the heat exchange medium, and then reheat part of the gas, while also transferring excess heat in the gas to the upstream and downstream devices of the secondary battery preparation device 100.

[0118] In addition, the heat exchange mechanism 160 can also exchange heat with the external environment (specifically, the environment inside the factory), thereby being linked to the temperature of the external environment. When the temperature of the external environment is higher than the preset temperature, the heat exchange mechanism 160 can absorb the heat of the external environment and store it in the gas to reduce the temperature of the external environment, and can transfer the excess heat to the upstream and downstream devices of the secondary battery preparation device 100. When the temperature of the external environment is lower than the preset temperature, the heat exchange mechanism 160 releases heat to the external environment to increase the temperature of the external environment.

[0119] In this way, the setting of the heat exchange mechanism 160 can realize the recycling and reuse of heat, reduce the gas consumption in the preparation process, and effectively reduce the manufacturing cost of the secondary battery.

[0120] The above-mentioned secondary battery preparation device 100 can fill the baking chamber 110a with dry inert gas with positive pressure during the battery preheating process, so that the battery cell 200 can be heated by heat convection on the basis of heat conduction and heat radiation. The synergistic effect of multiple heating methods effectively shortens the preheating time of the battery cell 200 and improves the preheating efficiency. Moreover, the setting of the heat exchange mechanism 160 in the secondary battery preparation device 100 can not only extract heat from the recovered gas for reuse, but also extract heat from the external environment to maintain the external environment at an ideal temperature. In addition, the heat exchange mechanism 160 can also provide heat to other devices to achieve efficient energy recovery and reuse.

[0121] Please combine Fig.11 As shown, the present application also provides a secondary battery preparation method, and the above-mentioned secondary battery preparation device 100 is applied to the secondary battery preparation method to prepare the secondary battery. The secondary battery preparation method mainly includes a battery cell production stage, a battery cell preheating stage, a battery cell heating stage, a battery cell cooling stage and a battery cell injection stage.

[0122] Specifically, the secondary battery preparation method includes the following steps:

[0123] Step S100: coating the positive electrode slurry on the positive electrode collector and drying it to obtain a positive electrode sheet, and coating the negative electrode slurry on the negative electrode collector and drying it to obtain a negative electrode sheet.

[0124] Specifically, components of the positive electrode slurry may include a positive electrode active material, a binder, and a conductive agent.

[0125] As non-limiting examples, the positive electrode active material may include one or more of an olivine-structured lithium-containing phosphate, a lithium transition metal oxide, and their respective modified compounds.

[0126] As non-limiting examples, the binder may include one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylate resin.

[0127] As non-limiting examples, the conductive agent may include one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0128] The positive electrode current collector may be a metal foil or a composite current collector, the metal foil may be an aluminum foil, and the composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. Non-limiting examples of polymer material substrates forming the polymer material base layer may include one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE) and the like. Non-limiting examples of metal materials forming the metal layer may include one or more of aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy.

[0129] The steps of coating the positive electrode slurry on the positive electrode collector and drying it to obtain the positive electrode sheet specifically include: dispersing the above-mentioned components for preparing the positive electrode sheet, such as the positive electrode active material, the conductive agent, the binder and any other components in a solvent (a non-limiting example of the solvent is N-methylpyrrolidone (NMP)) to form a positive electrode slurry, and then coating the positive electrode slurry on at least one side of the positive electrode collector. After drying and other processes, the positive electrode sheet can be obtained.

[0130] The components of the negative electrode slurry may include a negative electrode active material, a binder, and a conductive agent.

[0131] As non-limiting examples, the negative electrode active material may include one or more of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc. Among them, the silicon-based material may include one or more of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys; the tin-based material may include one or more of elemental tin, tin oxide compounds, and tin alloys.

[0132] As non-limiting examples, the binder may include one or more of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0133] As non-limiting examples, the conductive agent may include one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0134] The negative electrode current collector may be a metal foil or a composite current collector, the metal foil may be a copper foil, and the composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. Non-limiting examples of polymer material substrates forming the polymer material base layer may include one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE) and the like. Non-limiting examples of metal materials forming the metal layer may include one or more of copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy.

[0135] The steps of coating the negative electrode slurry on the negative electrode collector and drying it to obtain the negative electrode sheet specifically include: dispersing the above-mentioned components for preparing the negative electrode sheet, such as the negative electrode active material, the conductive agent, the binder and any other components in a solvent (a non-limiting example of the solvent is deionized water) to form a negative electrode slurry; coating the negative electrode slurry on at least one side of the surface of the negative electrode collector, and after drying and other processes, the negative electrode sheet can be obtained.

[0136] After step S100 , the process further includes step S110 : manufacturing the positive electrode sheet, the isolation film and the negative electrode sheet into an electrode assembly, and packaging the electrode assembly into a battery cell 200 .

[0137] Specifically, the material of the isolation membrane may include one or more of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride. The isolation membrane may be a single-layer film or a multi-layer composite film, without particular limitation. When the isolation membrane is a multi-layer composite film, the materials of each layer may be the same or different.

[0138] After obtaining the positive electrode sheet and the negative electrode sheet, the positive electrode sheet, the isolation film and the negative electrode sheet can be made into an electrode assembly through a winding process or a lamination process, and then packaged by an outer package to form a battery cell 200.

[0139] In some embodiments, the outer packaging may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc. In other embodiments, the outer packaging may also be a soft package, and the material of the soft package may be plastic, and non-limiting examples of plastic may include one or more of polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0140] During the charge and discharge process of the secondary battery, active ions are embedded and released back and forth between the positive electrode and the negative electrode. The isolation membrane is arranged between the positive electrode and the negative electrode, mainly to prevent the positive and negative electrodes from short-circuiting, while allowing ions to pass through.

[0141] Thus, after the above steps, the production of the battery cell 200 is preliminarily completed, and the battery cell 200 can enter the battery cell preheating stage for heating and temperature increase.

[0142] After step S110 , the process further includes step S120 : placing the battery cell 200 into the baking chamber 110 a .

[0143] Specifically, the battery cells 200 delivered by the upstream device are grabbed by the loading device and then placed in the heating assembly 120 located outside the baking oven 110. When the battery cells 200 in a heating assembly 120 reach the maximum capacity, the heating assembly 120 fully loaded with battery cells 200 can be moved to the baking chamber 110a of the baking oven 110 through the dispatching system.

[0144] After step S120 , the process further includes step S130 : heating the battery cell 200 and evacuating the baking chamber 110 a .

[0145] Specifically, after a certain number of battery cells 200 are placed in the baking chamber 110a, the oven door 114 of the baking oven 110 is closed and pressed against the oven body 112 under the drive of the driving mechanism 116, and compressed gas is filled into the sealing ring 118 to cause it to expand. At this time, the sealing ring 118 fits tightly against the oven door 114, thereby preventing the baking chamber 110a from exchanging gases with the external atmosphere.

[0146] Then, the heating base plate 121 of the heating assembly 120 heats the battery cell 200, and at the same time, the third exhaust pipeline 147 of the exhaust mechanism 140 evacuates the baking chamber 110a to form a vacuum environment in the baking chamber 110a.

[0147] After step S130 , the method further includes step S140 : when the real-time vacuum value in the baking chamber 110 a reaches a preset vacuum value, the battery cell 200 is continuously heated and auxiliary gas is filled into the baking chamber 110 a .

[0148] Specifically, when the oven door 114 of the baking oven 110 is closed, the real-time vacuum value in the baking chamber 110a can be detected in real time by the air pressure detection element. When the real-time vacuum value in the baking chamber 110a reaches a preset vacuum value, it indicates that the air in the baking chamber 110a has been completely extracted, thereby controlling the heating component 120 to continuously heat the battery cell 200 while filling the baking chamber 110a with auxiliary gas through the air intake mechanism 130.

[0149] Preferably, in the above steps, the auxiliary gas filled into the baking chamber 110a has a relatively high temperature. As a preferred embodiment, the temperature of the auxiliary gas is 90°C. As the auxiliary gas is filled, the pressure in the baking chamber 110a continues to rise to form a positive pressure environment. Specifically, in some embodiments, as the auxiliary gas is filled, the pressure in the baking chamber 110a can reach 0.5Mpa.

[0150] It should be noted that the continuous heating of the battery cell 200 in the above steps means that while the baking chamber 110 a is evacuated and filled with auxiliary gas, the heating component 120 always heats the battery cell 200 to continuously increase the temperature of the battery cell 200 .

[0151] As a preferred embodiment, the auxiliary gas is a dry inert gas with a positive pressure, and preferably, the inert gas includes at least one of helium and nitrogen. Specifically, in one embodiment, the inert gas is helium, and the thermal conductivity of helium is 7.5 times that of air. Therefore, during the preheating of the battery cell 100, the heating of the battery cell 200 can be achieved quickly.

[0152] In the above steps, in addition to utilizing the heating component 120 to realize heat conduction heating and real-time heat radiation heating, dry inert gas with positive pressure is introduced into the baking chamber 110a during the preheating process to form thermal convection heating. Under the synergistic heating of multiple heat transfer methods, not only the heating speed of the battery cell 200 is effectively improved and the preheating time of the battery cell 200 is shortened, but also the heating power of the heating component 120 can be reduced to save electric energy.

[0153] Among them, thermal convection heating refers to the transfer of heat through the flow of fluid. In a high-pressure environment, the distance between gas molecules is small, and the thermal conductivity of the gas is high, thereby accelerating the heating and heat dissipation speed. In a low-pressure environment, the distance between gas molecules is large, and the thermal conductivity of the gas is low, thereby slowing down the heating and heat dissipation speed. Therefore, an increase in air pressure will enhance the fluidity of the gas, thereby increasing the efficiency of convection heat transfer and accelerating the heating and heat dissipation speed. On the contrary, a decrease in air pressure will weaken the fluidity of the gas, reduce the efficiency of convection heat transfer, and slow down the heating and heat dissipation speed. Therefore, in the present application, by filling the baking chamber 110a with a dry inert gas with a positive pressure, the fluidity of the airflow in the baking chamber 110a can be enhanced, thereby accelerating the heating speed of the battery cell 200.

[0154] In the prior art, the battery cells are usually heated only by heat conduction, without actually adding high voltage to the inside of the baking chamber and maintaining the high voltage state to achieve rapid heat convection under high voltage, so the heating effect cannot be achieved.

[0155] In some embodiments, while executing step S140 , step S150 and step S160 may also be executed.

[0156] Step S150: recovering the auxiliary gas in the baking chamber 110a to the recovery chamber.

[0157] Specifically, while dry inert gas with positive pressure is introduced into the baking chamber 110a, the auxiliary gas in the baking chamber 110a can be recovered to the recovery chamber of the recovery unit 141 through the first exhaust pipeline 141 or the second exhaust pipeline 143 of the exhaust mechanism 140, so that the auxiliary gas can be reused to prevent waste of the auxiliary gas.

[0158] It should be noted that, in some embodiments, the heat exchange mechanism 160 can recover the heat of the gas not exceeding 60°C. Therefore, when the temperature of the auxiliary gas in the recovery chamber of the recovery unit 141 reaches 60°C, the exhaust mechanism 140 can be closed to stop the recovery of the auxiliary gas, while continuing to fill the baking chamber 110a with auxiliary gas.

[0159] Step S160: Drying and thermally managing the auxiliary gas recovered from the recovery chamber to form dry auxiliary gas with different temperatures, wherein a portion of the auxiliary gas releases heat to form a room temperature state, and another portion of the auxiliary gas absorbs heat to form a high temperature state.

[0160] Specifically, the auxiliary gas recovered to the recovery chamber of the recovery unit 141 can be further dried in the drying mechanism 150, and then transported to the heat exchange mechanism 160 for thermal management. A portion of the auxiliary gas in the heat exchange mechanism 160 releases heat to form a normal temperature state, so as to be used for cooling the battery cell 200 in subsequent processes; the other portion of the auxiliary gas absorbs heat to form a high temperature state, so as to be used in step S140, and continue to be filled into the baking chamber 110a to heat the battery cell 200.

[0161] In this way, by recovering, drying and thermally managing the auxiliary gas in the baking chamber 110a, the auxiliary gas can be recycled, the cost of using the auxiliary gas can be reduced, and the heat generated during the heating process can be fully utilized, significantly reducing the energy consumption of the battery cell 200 during the production process.

[0162] In some embodiments, the step of performing thermal management on the auxiliary gas includes step S161 and step S162 .

[0163] Step S161: obtaining heat of the auxiliary gas through a heat exchange medium.

[0164] Specifically, the heat exchange mechanism 60 exchanges heat with the recovered auxiliary gas through the heat exchange medium to obtain the heat of a part of the auxiliary gas, and the auxiliary gas releases heat to form a normal temperature state. The heated heat exchange medium exchanges heat with another part of the auxiliary gas, thereby heating the auxiliary gas to absorb heat and increase the temperature to form a high temperature state. The auxiliary gas in the normal temperature state is transported to the first storage cavity 1345 of the second air intake pipeline 134, and the auxiliary gas in the high temperature state is transported to the second storage cavity 1365 of the third air intake pipeline 136.

[0165] More specifically, in one embodiment, the temperature of the auxiliary gas in the normal temperature state is 20° C., which is beneficial to cooling the battery cell 200 , and the temperature of the auxiliary gas in the high temperature state is 90° C., which can be applied to continue heating the battery cell 200 in step S140 .

[0166] Step S162: In the target processing step, heat exchange is performed using the heat exchange medium after heat is obtained.

[0167] Specifically, the target processing step includes at least one of a step of drying a positive electrode sheet, a step of drying a negative electrode sheet, and a step of performing a formation treatment on the battery cell 200 .

[0168] In this way, the heat generated during the heating process can be used to supply heat to upstream and downstream processes, so that the waste heat generated during the heating process can be more effectively utilized, further reducing the production cost of the secondary battery.

[0169] In some embodiments, the heat exchange medium after obtaining heat can also be used to exchange heat with the external environment (specifically, the environment inside the factory) to adjust the temperature of the external environment. When the temperature of the external environment is lower than the preset temperature, the heat exchange mechanism 160 releases heat to the external environment to increase the temperature of the external environment, thereby ensuring the stability of the temperature of the external environment and further improving the energy utilization rate.

[0170] After step S140 , the method further includes step S170 : when the real-time temperature of the battery cell 200 reaches a preset preheating temperature, stopping charging the auxiliary gas into the baking chamber 110 a .

[0171] Specifically, the temperature detection unit detects the top temperature of the battery cell 200 in the four vertex areas of the accommodating cavity 120a of the heating assembly 120. When the top temperature of the battery cell 200 reaches the preset preheating temperature, it indicates that the overall temperature of all the battery cells 200 has reached the set requirement, so the preheating stage can be stopped, and the air intake mechanism 130 can be controlled to stop filling the auxiliary gas into the baking cavity 110a. In one embodiment, the preset preheating temperature is 100±5°C. It can be understood that the specific value of the preset preheating temperature is not limited and can be set as needed to meet different preheating requirements.

[0172] In this way, after the above steps, the preheating of the battery cell 200 is completed, and the battery cell 200 can enter the battery cell baking stage for baking and drying.

[0173] After step S170 , the method further includes step S180 : evacuating the baking chamber 110 a .

[0174] Specifically, after the auxiliary gas is stopped from being filled into the baking chamber 110a, the third exhaust pipe 147 of the exhaust mechanism 140 evacuates the baking chamber 110a, and at the same time the heating component 120 continues to heat the battery cell 200. Therefore, the moisture discharged from the battery cell 200 by heat is discharged through the third exhaust pipe 147, thereby drying the battery cell 200 and preventing moisture from remaining in the baking chamber 110a and unable to be discharged in time.

[0175] While executing step 180 , step S190 may also be executed: recovering the auxiliary gas extracted from the baking chamber 110 a to the recovery chamber.

[0176] Specifically, while the baking chamber 110a is evacuated, the auxiliary gas extracted from the baking chamber 110a can be recovered to the recovery chamber of the recovery unit 141 through the third exhaust pipeline 147 of the exhaust mechanism 140, thereby realizing the recycling of the auxiliary gas.

[0177] In some embodiments, when a certain vacuum value is reached in the baking chamber 110a, most of the gas extracted is vaporized water. At this time, the third exhaust pipeline 147 can transport the extracted water vapor to the exhaust end of the factory through the fourth exhaust pipeline 149 for discharge.

[0178] After step S190 , the method further includes step S200 : when the heating time reaches a preset heating time, the heating of the battery cell 200 is stopped, and the baking chamber 110 a is vented.

[0179] Specifically, when the heating time reaches the preset heating time, the baking of the battery cell 200 is completed, the heating component 120 stops heating the battery cell 200, and at the same time the third exhaust pipe 147 of the exhaust mechanism 140 evacuates the baking chamber 110a to extract the high-temperature gas in the baking chamber 110a.

[0180] After step S200 , the process further includes step S210 : injecting auxiliary gas at room temperature into the baking chamber 110 a .

[0181] Specifically, after the baking chamber 110a is evacuated, the second air inlet pipe 134 of the air inlet mechanism 130 fills the baking chamber 110a with auxiliary gas at room temperature, and uses the auxiliary gas at room temperature to cool the battery cells 200 in the baking chamber 110a.

[0182] In this way, the battery cell 200 is cooled in the baking chamber 110a without the need to transfer the battery cell 200 to a cooling furnace or other location, thereby reducing the purchase cost of the cooling furnace and preventing the waste heat of the battery cell 200 from being dissipated into the external environment, thereby effectively improving the efficiency of heat recovery.

[0183] While executing step S210 , step S220 and step S230 may also be executed.

[0184] Step S220: recovering the auxiliary gas in the baking chamber 110a to the recovery chamber.

[0185] While the auxiliary gas at room temperature is filled into the baking chamber 110a, the auxiliary gas in the baking chamber 110a can also be transported to the recovery chamber of the recovery unit 141 through the first exhaust pipeline 143 or the second exhaust pipeline 145 of the exhaust mechanism 140, thereby realizing the recycling of the auxiliary gas.

[0186] Step S230: Drying and thermally managing the auxiliary gas recovered from the recovery chamber to form dry auxiliary gas with different temperatures, wherein a portion of the auxiliary gas releases heat to form a room temperature state, and another portion of the auxiliary gas absorbs heat to form a high temperature state.

[0187] Specifically, the auxiliary gas recovered to the recovery chamber of the recovery unit 141 may further enter the drying mechanism 150 for drying, and then be transported to the heat exchange mechanism 160 for thermal management.

[0188] In some embodiments, the step of performing thermal management on the auxiliary gas includes step S231 and step S232 .

[0189] Step S231: obtaining heat of the auxiliary gas through a heat exchange medium.

[0190] Specifically, the heat exchange mechanism 60 obtains the heat of a part of the auxiliary gas through the heat exchange medium, and the part of the auxiliary gas releases heat to form a normal temperature state, and at the same time uses the obtained heat to heat the other part of the auxiliary gas, so that it absorbs heat to form a high temperature state. The auxiliary gas in the normal temperature state is transported to the second air inlet pipeline 134, and then continues to enter the baking chamber 110a to cool the battery cell 200, and the auxiliary gas in the high temperature state is transported to the second storage cavity 1365 of the third air inlet pipeline 136.

[0191] Step S232: In the target processing step, heat exchange is performed using the heat exchange medium after heat is obtained.

[0192] Specifically, the target processing step includes at least one of a step of drying to obtain a positive electrode sheet, a step of drying to obtain a negative electrode sheet, and a step of performing a formation treatment on the battery cell 200 .

[0193] In this way, the heat generated during the heating process can be used to supply heat to upstream and downstream processes, so that the waste heat generated during the heating process can be more effectively utilized, further reducing the production cost of the secondary battery.

[0194] In some embodiments, the heat exchange medium after obtaining heat can also be used to exchange heat with the external environment (i.e., the environment inside the factory) to adjust the temperature of the external environment. When the temperature of the external environment is lower than the preset temperature, the heat exchange mechanism 160 releases heat to the external environment to increase the temperature of the external environment, thereby ensuring the stability of the temperature of the external environment and further improving the energy utilization rate.

[0195] Since the battery cell 200 is always located in the baking chamber 110a during the process from heating to cooling, the waste heat after heating will not be dissipated into the external environment, which not only reduces the procurement cost of the traditional cooling furnace, but also improves the heat recovery efficiency, realizes the cooling heat waste recovery of the battery cell 200, and can also prevent the waste heat of the battery cell 200 from being dissipated into the external environment to increase the ambient temperature of the entire workshop, thereby avoiding increasing the energy consumption of the temperature control system.

[0196] Thus, after the above steps, the baking and drying of the battery cell 200 is completed, and then the battery cell 200 can be cooled to return to normal temperature.

[0197] After step S210 , the method further includes step S240 : when the real-time temperature of the battery cell 200 reaches a preset cooling temperature, stopping charging the auxiliary gas into the baking chamber 110 a .

[0198] Specifically, when the real-time temperature of the battery cell 200 obtained by the temperature detection unit reaches the preset cooling temperature, the surface battery cell 200 has completed cooling, so the air intake mechanism 130 stops filling the auxiliary gas into the baking chamber 110a.

[0199] After step S240 , the method further includes step S250 : extracting the auxiliary gas in the baking chamber 110 a and recycling it into the recycling chamber.

[0200] Specifically, the third exhaust pipeline 147 of the exhaust mechanism 140 extracts all the auxiliary gas in the baking chamber 110a into the recovery chamber to achieve the recovery of the auxiliary gas, thereby avoiding the waste of the auxiliary gas.

[0201] After step S250 , the method further includes step S260 : utilizing external ambient gas to evacuate the baking chamber 110 a .

[0202] When the auxiliary gas in the baking chamber 110a is completely recovered into the recovery chamber, the driving mechanism 116 opens the oven door 114 to use the external environment gas to evacuate the baking chamber 110a. Because the auxiliary gas has been completely recovered by the exhaust mechanism 140 before, it is ensured that the auxiliary gas will not leak.

[0203] After the above steps, the cooling of the battery cell 200 is basically completed, and the next liquid injection stage can be entered.

[0204] After step S260 , the process further includes step S270 : taking out the battery cell 200 from the baking chamber 110 a , injecting liquid into the battery cell 200 , and obtaining a secondary battery.

[0205] Specifically, after the sealing ring 118 is controlled to release vacuum, the driving mechanism 116 is controlled to open the furnace door 114, and the heating assembly 120 is taken out through the scheduling system and transferred to the liquid injection process, and finally a secondary battery is obtained. In some embodiments, after the step of injecting liquid into the battery cell 200, the step of: performing a formation treatment on the battery cell 200 is also included.

[0206] By repeatedly performing the above steps, continuous baking operation can be achieved, thereby continuously baking multiple batches of battery cells 200 .

[0207] In the above secondary battery preparation method, a dry inert gas with positive pressure is filled into the baking chamber 110a during the preheating process, so that the battery cell 200 can be heated by heat convection in addition to the heating by heat conduction and heat radiation. The synergistic effect of multiple heating methods effectively shortens the preheating time of the battery cell 200 and improves the preheating efficiency. Under the premise of meeting the unchanged production capacity, the number of baking ovens 110 can be reduced. Moreover, when cooling the battery cell 200, there is no need to carry the battery cell 200 a second time, nor is there any need to use a traditional cooling furnace to cool the battery cell 200. While saving production costs and equipment procurement costs, it maximizes the recovery and utilization of waste heat and effectively saves energy consumption.

[0208] The advantages of the present application are further described below in conjunction with specific examples. It should be understood that the following examples are only used to illustrate the present application and are not used to limit the scope of the present application.

[0209] Example 1

[0210] A method for preparing a secondary battery is provided, comprising the following steps:

[0211] Battery cell production stage:

[0212] First, the positive electrode slurry is applied to the positive electrode collector and dried to obtain a positive electrode sheet, and the negative electrode slurry is applied to the negative electrode collector and dried to obtain a negative electrode sheet.

[0213] Then, the positive electrode sheet, the separator and the negative electrode sheet are fabricated into an electrode assembly, and then the electrode assembly is packaged in an outer package to form a battery cell 200 .

[0214] Cell preheating stage:

[0215] The battery cells 200 delivered by the upstream device are grabbed by the loading device and placed into the heating assembly 120 located outside the baking oven 110 . The heating assembly 120 fully loaded with the battery cells 200 is then moved into the baking chamber 110 a of the baking oven 110 .

[0216] Afterwards, the driving mechanism 116 drives the oven door 114 of the baking oven 110 to close the baking chamber 110a, the heating assembly 120 heats the battery cell 200, and the third exhaust pipeline 147 of the exhaust mechanism 140 evacuates the baking chamber 110a to form a vacuum environment in the baking chamber 110a.

[0217] When the real-time vacuum value in the baking chamber 110a reaches the preset vacuum value, a high-temperature auxiliary gas is filled into the baking chamber 110a through the air intake mechanism 130. The auxiliary gas is dry helium with positive pressure. The auxiliary gas may specifically come from the first air intake pipeline 132 and / or the third air intake pipeline 136. At the same time, the auxiliary gas in the baking chamber 110a is recovered to the recovery chamber of the recovery unit 141 through the first exhaust pipeline 141 or the second exhaust pipeline 143 of the exhaust mechanism 140. When the temperature of the auxiliary gas in the recovery chamber reaches 60°C, the exhaust mechanism 140 may be closed to stop the recovery of the auxiliary gas, while the auxiliary gas continues to be filled into the baking chamber 110a.

[0218] The auxiliary gas recovered to the recovery chamber further enters the drying mechanism 150 for drying, and then is transported to the heat exchange mechanism 160. A portion of the auxiliary gas entering the heat exchange mechanism 160 releases heat to form a normal temperature state, and another portion of the auxiliary gas absorbs heat to form a high temperature state, and then can be re-charged into the baking chamber 110a through the third air inlet pipeline 136.

[0219] Cell baking stage:

[0220] When the real-time temperature of the battery cell 200 reaches the preset preheating temperature, the auxiliary gas is stopped from being charged into the baking chamber 110a, and the third exhaust pipe 147 of the exhaust mechanism 140 evacuates the baking chamber 110a, while the heating assembly 120 continues to heat the battery cell 200. Moreover, while the baking chamber 110a is evacuated, the auxiliary gas extracted from the baking chamber 110a can be recovered to the recovery unit 141 through the third exhaust pipe 147 of the exhaust mechanism 140.

[0221] Battery cell cooling stage:

[0222] When the heating time reaches the preset heating time, the baking of the battery cell 200 is completed, the heating component 120 stops heating the battery cell 200, and at the same time the third exhaust pipe 147 of the exhaust mechanism 140 evacuates the baking chamber 110a to extract the high-temperature gas in the baking chamber 110a.

[0223] Afterwards, the second air intake pipe 134 of the air intake mechanism 130 fills the baking chamber 110a with auxiliary gas at room temperature of 20°C, and uses the auxiliary gas at room temperature to cool the battery cells 200 in the baking chamber 110a. At the same time, the auxiliary gas in the baking chamber 110a is transported to the recovery unit 141 through the first exhaust pipe 143 or the second exhaust pipe 145 of the exhaust mechanism 140.

[0224] The auxiliary gas recovered to the recovery chamber can further enter the drying mechanism 150 for drying, and then be transported to the heat exchange mechanism 160. The heat exchange mechanism 160 obtains a portion of the heat of the auxiliary gas through the heat exchange medium, and the auxiliary gas releases heat to form a normal temperature state. The auxiliary gas in the normal temperature state is transported to the second air intake pipeline 134, and then continues to enter the baking chamber 110a to cool the battery cell 200. The other part of the auxiliary gas absorbs heat and continues to heat up, and then is transported to the second storage cavity 1365 of the third air intake pipeline 136.

[0225] Cell cooling stage:

[0226] When the real-time temperature of the battery cell 200 reaches the preset cooling temperature, the air intake mechanism 130 stops filling the baking chamber 110a with auxiliary gas, and simultaneously extracts the auxiliary gas in the baking chamber 110a and recovers it into the recovery chamber, thereby recovering the auxiliary gas.

[0227] Afterwards, the baking chamber 110 a is evacuated using external ambient gas, and the battery cell 200 is taken out of the baking chamber 110 a .

[0228] Battery filling stage:

[0229] The battery cell 200 is injected with liquid and formed to finally obtain a secondary battery.

[0230] Comparative Example 1

[0231] A secondary battery preparation method is provided, comprising most of the operations in Example 1, except that, in the battery cell preheating stage, after the driving mechanism 116 drives the oven door 114 of the baking oven 110 to close the baking chamber 110a, the third exhaust pipe 147 of the exhaust mechanism 140 evacuates the baking chamber 110a to form a vacuum environment in the baking chamber 110a, and the heating component 120 always heats the battery cell 200 in the vacuum environment until the real-time temperature of the battery cell 200 reaches the preset preheating temperature.

[0232] Comparative Example 2

[0233] A secondary battery preparation method is provided, including most of the operations in Example 1, except that, in the cell preheating stage, after the driving mechanism 116 drives the oven door 114 of the baking oven 110 to close the baking chamber 110a, the method includes the following steps:

[0234] S1: The heating assembly 120 heats the battery cell 200, and at the same time, the baking chamber 110a is evacuated and kept warm for 5 seconds;

[0235] S2: High-temperature gas is introduced into the baking chamber to break the vacuum so that the baking chamber 110a forms a normal pressure environment, and the normal pressure is maintained for 60 seconds;

[0236] S3: Repeat the operations of step S1 and step S2 20 times.

[0237] Effect test: Calculate the time from when the heating component 120 starts to heat the battery cell 200 until the real-time temperature of the battery cell 200 reaches the preset preheating temperature and stops heating the battery cell 200, and the following table can be obtained:

[0238] Table 1

[0239]

[0240] As can be seen from Table 1, when the real-time temperature of the battery cell 200 reaches 100°C, the preheating time of the battery cell 200 is 100 minutes using the preparation method in Example 1. However, when the preparation method in Comparative Example 1 is used, since high-temperature and positive-pressure dry helium is not filled into the baking chamber 110a during the preheating stage, when the real-time temperature of the battery cell 200 reaches 100°C, the preheating time of the battery cell 200 is 180 minutes, which is much longer than the preheating time of the battery cell 200 in Example 1. Using the preparation method in Comparative Example 2, during the preheating stage, the baking chamber 110a continuously cycles between the normal pressure environment and the vacuum environment, which is different from the baking chamber 110 in the present application in which high-temperature and positive-pressure dry helium is continuously filled into the baking chamber 110 to form a positive-pressure environment. Therefore, when the real-time temperature of the battery cell 200 reaches 100°C, the preheating time of the battery cell 200 is 170 minutes, which is less than the preheating time of the battery cell 200 in Comparative Example 1 but still significantly greater than the preheating time of the battery cell 200 in Example 1.

[0241] It can be seen that in Example 1, a shorter preheating time can meet the preheating requirements of the battery cell, thereby shortening the preparation time of the secondary battery, saving the cost of the battery cell baking process, and improving production efficiency.

[0242] The present application also provides a secondary battery, which is prepared by the secondary battery preparation device 100 using the secondary battery preparation method. The secondary battery includes a housing and an electrode assembly encapsulated in the housing, the electrode assembly includes a positive electrode sheet, a separator and a negative electrode sheet, and is formed by stacking or winding.

[0243] The present application also provides an energy storage system, comprising the above-mentioned secondary battery.

[0244] In some embodiments of the present application, the energy storage system includes an electrically connected energy storage device and a power converter, the power converter is used to perform power conversion processing on the voltage and / or current, and input the changed voltage and / or current to the energy storage device, so that the energy storage device can meet the power requirements of the electrical equipment.

[0245] In other embodiments of the present application, the energy storage system includes but is not limited to any one of an energy storage power station, a household energy storage system, or a data center energy storage system.

[0246] The present application also provides an electrical device, comprising the above-mentioned secondary battery.

[0247] In some embodiments of the present application, the electrical equipment may include but is not limited to mobile phones, tablets, laptops, electric toys, electric tools, battery cars, electric cars, ships, spacecraft, etc. Among them, the electric toys may include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys and electric airplane toys, etc., and the spacecraft may include airplanes, rockets, space shuttles and spacecrafts, etc.

[0248] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0249] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A method for preparing a secondary battery, characterized in that: The following steps are involved: The positive electrode sheet, the separator and the negative electrode sheet are manufactured into an electrode assembly, and the electrode assembly is packaged to form a battery cell; placing the battery cell into a baking chamber; heating the battery core and evacuating the baking chamber; When the real-time vacuum value in the baking chamber reaches a preset vacuum value, the battery cell is continuously heated and an auxiliary gas is filled into the baking chamber; wherein the auxiliary gas is a dry inert gas with a positive pressure; When the real-time temperature of the battery cell reaches a preset preheating temperature, stopping filling the auxiliary gas into the baking chamber; Taking out the battery cell from the baking chamber and injecting liquid into the battery cell to obtain a secondary battery; While continuing to heat the battery cell and filling the baking chamber with auxiliary gas, the following steps are also included: Recovering the auxiliary gas in the baking chamber to a recovery chamber; The auxiliary gas recovered by the recovery chamber is dried and thermally managed to form dry auxiliary gas with different temperatures, wherein a part of the auxiliary gas releases heat to form a normal temperature state, and another part of the auxiliary gas absorbs heat to form a high temperature state.

2. The method for preparing a secondary battery according to claim 1, characterized in that: When the real-time temperature of the battery cell reaches the preset preheating temperature, after the step of stopping the filling of the auxiliary gas into the baking chamber, the method further includes the following steps: evacuating the baking chamber; The auxiliary gas extracted from the baking chamber is recovered to the recovery chamber.

3. The method for preparing a secondary battery according to claim 2, characterized in that: After the step of recovering the auxiliary gas extracted from the baking chamber to the recovery chamber, the following steps are also included: When the heating time reaches a preset heating time, the heating of the battery cell is stopped, and the baking chamber is vented; Filling the auxiliary gas at room temperature into the baking chamber; When the real-time temperature of the battery cell reaches a preset cooling temperature, the auxiliary gas is stopped from being filled into the baking chamber.

4. The method for preparing a secondary battery according to claim 3, characterized in that: While the step of filling the auxiliary gas at room temperature into the baking chamber, the following steps are also included: Recovering the auxiliary gas in the baking chamber to the recovery chamber; The auxiliary gas recovered by the recovery chamber is dried and thermally managed to form dry auxiliary gas with different temperatures, wherein a part of the auxiliary gas releases heat to form a normal temperature state, and another part of the auxiliary gas absorbs heat to form a high temperature state.

5. The method for preparing a secondary battery according to claim 3, characterized in that: When the real-time temperature of the battery cell reaches a preset cooling temperature, after the step of stopping the filling of the auxiliary gas into the baking chamber, the method further includes the following steps: Extracting the auxiliary gas in the baking chamber and recycling it into the recovery chamber; The baking chamber is evacuated by using external ambient gas.

6. The method for preparing a secondary battery according to any one of claims 1 to 5, characterized in that: The battery cell is accommodated in a receiving cavity, and the real-time temperature of the battery cell is the top temperature of at least one of the battery cells located in four vertex corners of the receiving cavity.

7. The method for preparing a secondary battery according to claim 1, characterized in that: Before the step of forming the electrode assembly from the positive electrode sheet, the separator and the negative electrode sheet, the method further includes: The positive electrode slurry is applied to the positive electrode current collector and dried to obtain the positive electrode sheet, and the negative electrode slurry is applied to the negative electrode current collector and dried to obtain the negative electrode sheet; After the step of injecting liquid into the battery cell, the method further comprises: Performing a formation treatment on the battery cell; The step of thermally managing the auxiliary gas further comprises: Obtaining heat from the auxiliary gas through a heat exchange medium; In the target processing step, heat is exchanged using the heat exchange medium after the heat is obtained; The target processing step includes at least one of a step of drying the positive electrode sheet, a step of drying the negative electrode sheet, and a step of performing a formation treatment on the battery cell.

8. A secondary battery preparation device, applied to the secondary battery preparation method according to any one of claims 1 to 7, characterized in that: The secondary battery preparation device comprises: A baking oven, comprising a baking chamber and an air inlet and an air outlet respectively connected to the baking chamber; A heating component is disposed in the baking cavity, the heating component has a receiving cavity with one end open, and the heating component is used to receive and heat the battery core; an air intake mechanism, connected to the baking oven through the air intake port, the air intake mechanism being used to fill the baking cavity with gas; and An exhaust mechanism is connected to the baking oven through the exhaust port, and the exhaust mechanism is used to extract the gas in the baking chamber.

9. The secondary battery preparation device according to claim 8, characterized in that: The secondary battery preparation device also includes a drying mechanism and a heat exchange mechanism. The drying mechanism is connected between the exhaust mechanism and the heat exchange mechanism and is used to dry the gas. The heat exchange mechanism is connected between the drying mechanism and the air intake mechanism and is used to perform heat exchange.

10. The secondary battery preparation device according to claim 9, characterized in that: The air intake mechanism comprises: a first air inlet pipeline, wherein the air inlet end of the first air inlet pipeline is used to connect to an external air supply device, the air outlet end of the first air inlet pipeline is connected to the baking oven through the air inlet, and the first air inlet pipeline is used to transport gas; a second air inlet pipeline, wherein an air inlet end of the second air inlet pipeline is connected to the heat exchange mechanism, an air outlet end of the second air inlet pipeline is connected to the baking oven through the air inlet, and the second air inlet pipeline is used to store and transport room temperature gas; and A third air inlet pipeline, the air inlet end of the third air inlet pipeline is connected to the heat exchange mechanism, the air outlet end of the third air inlet pipeline is connected to the baking oven through the air inlet, and the third air inlet pipeline is used to store and transport high-temperature gas.

11. The secondary battery manufacturing device according to claim 8, characterized in that: The exhaust mechanism comprises: a recovery unit for storing gas; a first exhaust pipeline, wherein an air inlet end of the first exhaust pipeline is connected to the baking oven through the exhaust port, an air outlet end of the first exhaust pipeline is connected to the recovery unit, and the first exhaust pipeline is used to transport gas; a second exhaust pipeline, wherein an air inlet end of the second exhaust pipeline is connected to the baking oven through the exhaust port, an air outlet end of the second exhaust pipeline is connected to the recovery unit, a pressurizing unit is provided in the second exhaust pipeline, and the second exhaust pipeline is used to transport gas; and The third exhaust pipeline, the air inlet end of the third exhaust pipeline is connected to the baking oven through the exhaust port, the air outlet end of the third exhaust pipeline is connected to the recovery unit, the third exhaust pipeline is provided with a vacuum unit, and the third exhaust pipeline is used to transport gas.

12. The secondary battery preparation device according to claim 8, characterized in that: The heating assembly further includes at least one temperature detection module, which is installed at the open end of the accommodating cavity and is used to detect the top temperature of at least one of the battery cells located in the four vertex corner areas of the accommodating cavity.

13. A secondary battery, characterized in that: The secondary battery is prepared by the secondary battery preparation device according to any one of claims 8 to 12 using the secondary battery preparation method according to any one of claims 1 to 7.

14. An energy storage system, characterized in that: Comprising the secondary battery as claimed in claim 13.

15. An electrical equipment, characterized in that: Comprising the secondary battery as claimed in claim 13.

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