Method and apparatus for manufacturing secondary battery

Abstract

Provided are a method and an apparatus for manufacturing a secondary battery in which the efficiency of a secondary battery manufacturing process is improved and the secondary battery is more structurally stable. The method for manufacturing a secondary battery includes: providing a secondary battery; injecting an electrolyte into the secondary battery; activating the secondary battery into which the electrolyte is injected, and applying ultrasonic waves to the electrolyte in the secondary battery.

Description

Technical Field

[0001] The embodiments relate to a method and apparatus for manufacturing secondary batteries. More specifically, the embodiments relate to a method and apparatus for manufacturing secondary batteries with improved efficiency in the secondary battery manufacturing process and improved performance and structural stability. Background Technology

[0002] With the rapid development of the electrical, electronics, communications, and computer industries, the demand for high-performance and highly safe rechargeable batteries is increasing rapidly. In particular, as electrical and electronic products are trending towards being lighter, thinner, smaller, and more portable, rechargeable batteries, as a key component, also need to be lighter and smaller.

[0003] The depletion of oil reserves and the environmental pollution problems such as air pollution and noise caused by the massive increase in vehicles necessitate new energy sources. Therefore, the demand for developing electric vehicles is increasing, and there is a need to develop batteries with high power and high energy density as the power source for electric vehicles.

[0004] In response to these demands, the most attention recently focused on high-performance, next-generation, and high-tech new batteries is on secondary batteries, in which lithium, used as the anode, has a very low density and standard reduction potential, and therefore can be used as an electrode material for high-energy-density batteries.

[0005] In the manufacturing process of this type of secondary battery, charging and activation can be performed. However, when the secondary battery is charged at a high speed to shorten the activation time, the performance and / or structural stability of the secondary battery may be reduced.

[0006] The information disclosed in this section on background art is intended only to enhance the understanding of the background of this disclosure, and therefore may contain information that is not related to the art. Summary of the Invention

[0007] The embodiments aim to provide a method and apparatus for manufacturing secondary batteries that improves the efficiency of the secondary battery manufacturing process and makes the secondary batteries structurally more stable.

[0008] The purposes of this disclosure are not limited to those described herein, and other purposes and advantages of this disclosure may be understood from the description.

[0009] Other aspects will be set forth in part in the description which follows, and will be apparent in part from the description, or may be learned by practicing the embodiments presented in this disclosure.

[0010] According to embodiments of this disclosure for achieving the above-mentioned technical objectives, a method for manufacturing a secondary battery includes: providing a secondary battery; injecting an electrolyte into the secondary battery; activating the secondary battery in which the electrolyte is injected; and applying ultrasonic waves to the electrolyte in the secondary battery.

[0011] In this embodiment, the activation of the secondary battery and the application of ultrasound to the electrolyte can be performed simultaneously.

[0012] In this embodiment, ultrasonic waves can be applied to the electrolyte while the state of charge of the secondary battery increases.

[0013] In this embodiment, the activation of the secondary battery may include: initially charging the secondary battery and aging the initially charged secondary battery, and may simultaneously apply ultrasonic waves to the electrolyte while performing the initial charging of the secondary battery.

[0014] In this embodiment, the frequency of the ultrasound can be variable during the application of ultrasound to the electrolyte.

[0015] In this embodiment, the frequency of the ultrasonic waves applied to the electrolyte can be adjusted according to the charging state of the secondary battery.

[0016] In this embodiment, when the state of charge of the secondary battery is less than a preset value, the frequency of the ultrasonic waves applied to the electrolyte can be adjusted to be higher than the frequency of the ultrasonic waves applied to the electrolyte when the state of charge of the secondary battery is greater than the preset value.

[0017] In this embodiment, the frequency of the ultrasonic waves applied to the electrolyte can be adjusted according to the activation time of the secondary battery.

[0018] In this embodiment, when the activation time of the secondary battery is shorter than a preset time, the frequency of the ultrasonic waves applied to the electrolyte can be adjusted to be higher than the frequency of the ultrasonic waves applied to the electrolyte when the activation time of the secondary battery is longer than the preset time.

[0019] In this embodiment, applying ultrasound to the electrolyte may include: applying ultrasound with a first frequency to the electrolyte for a first time, and applying ultrasound with a second frequency lower than the first frequency to the electrolyte for a second time shorter than the first time.

[0020] In this embodiment, the application of ultrasound with a first frequency and the application of ultrasound with a second frequency can be repeated.

[0021] In this embodiment, the ratio of the first time to the second time can be 3 to 5.

[0022] In this embodiment, the frequency of the ultrasound applied to the electrolyte can be from 20 kHz to 20 MHz.

[0023] According to an embodiment of the present disclosure for achieving the above-mentioned technical objectives, an apparatus for manufacturing a secondary battery includes: a charging unit electrically connected to the secondary battery and configured to charge the secondary battery, wherein an electrolyte is provided in the secondary battery; an ultrasonic generator configured to apply ultrasonic waves to one side of the secondary battery; and a controller configured to control the driving of the ultrasonic generator while the secondary battery is being charged.

[0024] In this embodiment, the controller can be configured to control the drive of the ultrasonic generator to adjust the frequency of the ultrasonic waves applied to the secondary battery.

[0025] In this embodiment, the controller can measure the state of charge of the secondary battery and adjust the frequency of the ultrasonic waves applied to the secondary battery according to the state of charge of the secondary battery.

[0026] In this embodiment, when the state of charge of the secondary battery is less than a preset value, the controller can adjust the frequency of the ultrasonic waves applied to the secondary battery to be higher than the frequency of the ultrasonic waves applied to the secondary battery when the state of charge of the secondary battery is greater than the preset value.

[0027] In this embodiment, the controller can adjust the frequency of the ultrasonic waves applied to the secondary battery according to the charging time of the secondary battery.

[0028] In this embodiment, when the charging time of the secondary battery is shorter than a preset time, the controller can adjust the frequency of the ultrasonic waves applied to the secondary battery to be higher than the frequency of the ultrasonic waves applied to the secondary battery when the charging time of the secondary battery is longer than the preset time.

[0029] In this embodiment, the frequency of the ultrasonic waves applied to the secondary battery by the ultrasonic generator can be from 20 kHz to 20 MHz. Attached Figure Description

[0030] The above and other aspects, features, and advantages of certain embodiments will become more apparent from the following description taken in conjunction with the accompanying drawings.

[0031] The accompanying drawings illustrate exemplary embodiments of the present disclosure and, together with the following detailed description, serve to provide a further understanding of the technical spirit of the present disclosure. However, the present disclosure is not limited to the details shown in the drawings, in which:

[0032] Figure 1 This is a schematic diagram of an apparatus for manufacturing secondary batteries according to an embodiment of the present disclosure;

[0033] Figure 2It is a graph used to describe a method, through which the controller... Figure 1 The charging state of the secondary battery depicted in the diagram is controlled by the frequency of the ultrasonic waves applied by the ultrasonic generator.

[0034] Figure 3 It is a graph used to describe a method, through which the controller... Figure 1 The charging time of the secondary battery described in the text is controlled by the frequency of the ultrasonic waves applied by the ultrasonic generator.

[0035] Figure 4 It is used to describe ultrasonic generators according to Figure 1 The graph depicts the period of the ultrasonic wave applied by the controller's control signal.

[0036] Figure 5 This is a flowchart describing a method for manufacturing a secondary battery according to embodiments of the present disclosure; and

[0037] Figure 6 It is a flowchart describing the process of activating a secondary battery and applying ultrasound to the electrolyte. Detailed Implementation

[0038] Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein the same reference numerals refer to the same elements throughout. In this regard, the present embodiments may take different forms and should not be construed as limited to the description set forth herein. Accordingly, embodiments are described below only by reference to the accompanying drawings to explain aspects. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. When preceding / following a list of elements, expressions such as “at least one of…” modify the entire list of elements, but not individual elements of the list.

[0039] In the following description, exemplary embodiments of the present disclosure will be described with reference to the accompanying drawings. Before description, it should be understood that the terminology used in the specification and appended claims should not be construed as limited to its general or dictionary meaning, but should be interpreted based on the principle that inventors are permitted to appropriately define terms for best description, and on the meanings and concepts corresponding to the technical aspects of the present disclosure. Accordingly, the embodiments disclosed in this specification and the configurations illustrated in the drawings are merely the most exemplary embodiments of the present disclosure and do not represent all the technical ideas of the present disclosure; therefore, it should be understood that various equivalents and modifications may exist at the time of filing this application.

[0040] Furthermore, the terms “including and encompassing” and / or variations thereof as used in this specification shall be construed as specifying the presence of the described shapes, numbers, steps, operations, components, elements and / or groups thereof, and do not exclude the presence or addition of other shapes, numbers, operations, components, elements and / or groups thereof.

[0041] For example, to better understand this disclosure, the accompanying drawings are not shown to actual scale, and the dimensions of some elements may be exaggerated. For example, in different embodiments, the same reference numerals may be assigned to the same parts.

[0042] Including two comparison objects as "identical" means that the two comparison objects are "substantially identical." Therefore, substantially identical can include deviations considered low in the art, such as 5% or less. For example, from an average perspective, the uniformity of parameters in a region can mean uniformity.

[0043] It will be understood that although the terms first and second, etc., are used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another, and a first element may also be a second element unless otherwise specifically described.

[0044] Throughout this instruction manual, each element may be singular or plural unless otherwise specified.

[0045] When it is said that any element is positioned on the “upper (or lower)” of a component or on the “above (or below)” of a component, this may mean not only that the arbitrary element is positioned to contact the upper (or lower) surface of the component, but also that another element may be positioned between the component and the arbitrary element positioned on the upper (or lower) surface of the component.

[0046] Furthermore, when it is said that one element is “connected” or “coupled” to another element, this may mean that the elements are directly connected or coupled to each other, but it should be understood that another element may be “placed” between these elements, or that these elements may be “connected” or “coupled” to each other via another element. Further, the term “electrical connection” may mean not only “direct connection” but may also include “connection via other inserted elements.”

[0047] Throughout this instruction manual, "A and / or B" refers to "A, B, or A and B" unless otherwise specified. That is, "and / or" includes all or any combination of the listed items. "C to D" refers to C or more and D or fewer, unless otherwise specified.

[0048] The terminology used in this specification is for describing embodiments of this disclosure and is not intended to limit this disclosure.

[0049] Figure 1This is a schematic diagram illustrating an apparatus for manufacturing secondary batteries according to an embodiment of the present disclosure. Figure 2 It is a graph used to describe a method, through which the controller... Figure 1 The state of charge (SOC) of the secondary battery depicted controls the frequency of the ultrasonic waves applied from the ultrasonic generator. Figure 3 It is a graph used to describe a method, through which the controller... Figure 1 The charging time of the secondary battery depicted is controlled by the frequency of the ultrasonic waves applied from the ultrasonic generator. Figure 4 It is used to describe ultrasonic generators according to Figure 1 The graph depicts the period of the ultrasonic waves applied by the controller's control signal.

[0050] refer to Figure 1 According to embodiments of the present disclosure, an apparatus 1 for manufacturing a secondary battery LC may include a charging unit 100, an ultrasonic generator 200, and a controller 300. The apparatus 1 for manufacturing a secondary battery can perform a process for activating the secondary battery LC by applying a voltage to the secondary battery LC, and can apply ultrasonic waves to one side of the secondary battery LC while the voltage is being applied.

[0051] refer to Figure 1 According to embodiments of the present disclosure, the charging unit 100 can be electrically connected to a secondary battery LC and can charge the secondary battery LC by applying a voltage to the secondary battery LC. The charging unit 100 can perform an activation process or a formation process of the secondary battery LC during charging / discharging using methods such as constant current charging / discharging, pulse charging / discharging, or step-providing methods. Through these methods, a solid electrolyte interface (SEI) film can be formed inside the secondary battery LC.

[0052] The charging unit 100 can charge and discharge the secondary battery LC one to ten times within a voltage range of 3.5V to 4.0V for 10 minutes to 5 hours. By performing several charge / discharge cycles within this voltage range, the SEI film can be formed with an average thickness within a specific range and also with high density. Furthermore, the composition of the components constituting the SEI film can be controlled. Therefore, the components of the SEI film can be prevented from separating from the surface of the cathode active material during high-speed charging / discharging. In other words, component separation of the SEI film can be prevented, and the SEI film can be formed thicker, thereby providing a secondary battery LC that exhibits excellent battery performance even during high-speed charging / discharging.

[0053] The charging unit 100 can be electrically connected to the controller 300, and the controller 300 can obtain information about the state of charge (SOC) of the secondary battery LC from the charging unit 100. However, embodiments of this disclosure are not limited thereto, and the controller 300 can be directly electrically connected to the secondary battery LC to obtain information about the SOC of the secondary battery LC.

[0054] refer to Figure 1 According to an embodiment of the present disclosure, the ultrasonic generator 200 can generate ultrasonic vibrations and apply ultrasonic waves to one side of the secondary battery LC. The frequency of the ultrasonic waves applied by the ultrasonic generator 200 can be in the range of 20 kHz to 20 MHz. The ultrasonic generator 200 can be electrically connected to a controller 300, so that the frequency of the ultrasonic waves applied to the secondary battery LC and the period for applying the ultrasonic waves can be changed according to the control signal of the controller 300.

[0055] In the following description of the method for manufacturing a secondary battery, the frequency of the ultrasonic waves, which is changed according to the control signal of the controller 300, will be described in detail.

[0056] In this specification, "secondary battery LC" is a general term that includes, for example, cylindrical secondary batteries, pouch-type secondary batteries, and prismatic secondary batteries.

[0057] Refer again Figure 1 When the secondary battery LC is a cylindrical secondary battery, the ultrasonic generator 200 can apply ultrasonic waves to the center portion of the side surface of the secondary battery LC. Although not shown in the figures, when the secondary battery LC is a pouch-shaped or prismatic secondary battery, the ultrasonic generator 200 can apply ultrasonic waves to the center portion of the front surface of the secondary battery LC.

[0058] By applying ultrasound to the secondary battery LC during the activation or formation process, the amount of gas included in the electrolyte can be reduced, electrolyte impregnation can be promoted, the exchange current density of the electrodes of the secondary battery LC can be improved, the overpotential of the anode can be reduced, and / or the side reaction phenomena between lithium metal and electrolyte can be reduced.

[0059] The ultrasonic generator 200 according to embodiments of the present disclosure can be moved in a predetermined direction by receiving power from an external source. For example, a controller 300 can be connected to the charging unit 100 to obtain information about the shape or type of the secondary battery LC to which an activation process, formation process, or initial charging is performed. The controller 300 can then receive the obtained information about the shape or type of the secondary battery LC to adjust the relative position of the ultrasonic generator 200 to the secondary battery LC. For example, the ultrasonic generator 200 can be moved to adjust the position where ultrasonic waves are applied to the secondary battery LC. Therefore, the position where ultrasonic waves are applied can be appropriately adjusted according to the type and / or shape of the secondary battery LC.

[0060] refer to Figure 1 According to embodiments of the present disclosure, the controller 300 can control the driving of the ultrasonic generator 200 while the secondary battery LC is being charged, and the controller 300 can be electrically connected to the ultrasonic generator 200. In particular, the controller 300 can control the driving of the ultrasonic generator 200 to adjust the frequency of the ultrasonic waves applied to the secondary battery LC.

[0061] refer to Figure 2 The controller 300 can measure the state of charge (SOC) of the secondary battery LC and adjust the frequency of the ultrasonic waves applied to the secondary battery LC according to the SOC. For example, when the SOC of the secondary battery LC is less than a preset value, the controller 300 can adjust the frequency of the ultrasonic waves applied to the secondary battery LC to be relatively higher than the frequency applied when the SOC of the secondary battery LC is greater than the preset value. During the activation or formation process, the secondary battery LC can be subjected to main charging or initial charging. Therefore, its SOC can be gradually increased.

[0062] Refer again Figure 2 When the state of charge (SOC) of the secondary battery LC is less than a preset first SOC V1, the controller 300 can control the drive of the ultrasonic generator 200 to adjust the frequency of the ultrasonic waves applied to the secondary battery LC to a first frequency f1. When the SOC of the secondary battery LC is greater than the first SOC V1, the controller 300 can control the drive of the ultrasonic generator 200 to adjust the frequency of the ultrasonic waves applied to the secondary battery LC to a second frequency f2, which is lower than the first frequency f1.

[0063] In one embodiment, the first SOC V1 can be in the range of 1% to 10% or 2% to 5%. Similarly, in another embodiment, the first frequency f1 can be in the range of 10MHz to 20MHz, and the second frequency f2 can be in the range of 50kHz to 10MHz.

[0064] Refer to again Figure 2When the state of charge (SOC) of the secondary battery LC is less than a second SOC (V2) which is greater than the first SOC (V1), the controller 300 can control the drive of the ultrasonic generator 200 to adjust the frequency of the ultrasonic waves applied to the secondary battery LC to a second frequency (f2). Furthermore, when the SOC of the secondary battery LC is greater than the second SOC (V2), the controller 300 can control the drive of the ultrasonic generator 200 to adjust the frequency of the ultrasonic waves applied to the secondary battery LC to a third frequency (f3) which is lower than the second frequency (f2).

[0065] In an embodiment, the second SOC V2 can be in the range of 10% to 20%, and the third frequency f3 can be in the range of 20kHz to 50kHz.

[0066] refer to Figure 3 According to an embodiment of the present disclosure, the controller 300 can adjust the frequency of the ultrasonic waves applied to the secondary battery LC based on the charging time of the secondary battery LC. For example, when the charging time of the secondary battery LC is shorter than a preset time, the controller 300 can adjust the frequency of the ultrasonic waves applied to the secondary battery LC to be higher than the frequency of the ultrasonic waves applied to the secondary battery LC when the charging time of the secondary battery LC is longer than the preset time.

[0067] refer to Figure 3 When the charging time of the secondary battery LC is shorter than a preset first charging time t1, the controller 300 can control the drive of the ultrasonic generator 200 to adjust the frequency of the ultrasonic waves applied to the secondary battery LC to a first frequency f1. When the charging time of the secondary battery LC is longer than the first charging time t1, the controller 300 can control the drive of the ultrasonic generator 200 to adjust the frequency of the ultrasonic waves applied to the secondary battery LC to a second frequency f2 lower than the first frequency f1. In this embodiment, the first frequency f1 can be in the range of 10MHz to 20MHz, and the second frequency f2 can be in the range of 50kHz to 10MHz.

[0068] Refer again Figure 3 When the charging time of the secondary battery LC is between the first charging time t1 and the second charging time t2, the controller 300 can control the drive of the ultrasonic generator 200 to adjust the frequency of the ultrasonic waves applied to the secondary battery LC to a second frequency f2. Furthermore, when the charging time of the secondary battery LC is longer than the second charging time t2, the controller 300 can control the drive of the ultrasonic generator 200 to adjust the frequency of the ultrasonic waves applied to the secondary battery LC to a third frequency f3, which is lower than the second frequency f2. In this embodiment, the third frequency f3 can be in the range of 20kHz to 50kHz.

[0069] refer to Figure 4According to an embodiment of the present disclosure, the controller 300 can control the driving of the ultrasonic generator 200 to control the period during which the ultrasonic generator 200 applies ultrasonic waves to the secondary battery LC. For example, the controller 300 can control the driving of the ultrasonic generator 200 such that an ultrasonic wave with a frequency f1' is applied to the secondary battery LC for a first time p1, and can also control the driving of the ultrasonic generator 200 such that an ultrasonic wave with a frequency f2' lower than the frequency f1' is applied to the secondary battery LC for a second time p2 shorter than the first time p1.

[0070] refer to Figure 2 and Figure 4 When the SOC of the secondary battery LC is less than the first SOC V1, the controller 300 can perform control to adjust the first frequency f1 to frequency f1'. When the SOC of the secondary battery LC is greater than the first SOC V1 and less than the second SOC V2, the controller 300 can perform control to adjust the frequency f1' to the second frequency f2. When the SOC of the secondary battery LC is greater than the second SOC V2, the controller 300 can perform control to adjust the frequency f1' to the third frequency f3.

[0071] In an embodiment, frequency f2' can be 0 Hz or approximately 0 Hz. Furthermore, in an embodiment, the ratio of frequency f1' to frequency f2' can be in the range of 10 to 100.

[0072] In an embodiment, the ratio of the first time p1 to the second time p2 can be in the range of 3 to 5. For example, when the first time p1 is about 60 seconds, the second time p2 can be in the range of 12 to 20 seconds; when the first time p1 is about 30 seconds, the second time p2 can be in the range of 6 to 10 seconds; and when the first time p1 is about 5 seconds, the second time p2 can be in the range of 1 to 2 seconds.

[0073] Therefore, according to embodiments of this disclosure, the stress applied to the electrolyte due to the continuous application of ultrasound can be minimized.

[0074] Hereinafter, a method for manufacturing a secondary battery according to embodiments of the present disclosure will be described.

[0075] In this disclosure, for ease of description, the methods for manufacturing secondary batteries are described in time series. However, the processes and each operation described below are not limited to the specific order set forth herein and can be performed simultaneously.

[0076] Figure 5 This is a flowchart of a method for manufacturing a secondary battery according to an embodiment of the present disclosure. Figure 6 It is used to describe in Figure 5The flowcharts depict the operation S300 of activating the secondary battery and the operation S400 of applying ultrasound to the electrolyte in the method described herein.

[0077] refer to Figure 5 The method for manufacturing a secondary battery according to embodiments of the present disclosure may include an operation S100 of providing a secondary battery, an operation S200 of injecting an electrolyte into the secondary battery, an operation S300 of activating the secondary battery in which the electrolyte is injected, and an operation S400 of applying ultrasound to the electrolyte injected into the secondary battery.

[0078] In operation S100 of providing a secondary battery, the user can provide a secondary battery LC including an electrode assembly and a housing configured to house the electrode assembly therein. When the secondary battery LC is a cylindrical secondary battery, the secondary battery LC may include an electrode assembly, a housing configured to house the electrode assembly therein, a cover assembly connected to an opening in the housing to seal the housing, and an insulating plate located inside the housing between the electrode assembly and the cover assembly.

[0079] The electrode assembly may include a diaphragm and a first electrode and a second electrode, wherein the first electrode and the second electrode are positioned such that the diaphragm is positioned between the first electrode and the second electrode. The electrode assembly may be wound in the form of an electrode core.

[0080] The first electrode may include a first substrate and a first active material layer located on the first substrate. A first lead tab may extend outward from a first uncoated portion of the first substrate where the first active material layer is not disposed. The first lead tab may be electrically connected to a cover assembly.

[0081] The second electrode may include a second substrate and a second active material layer located on the second substrate. A second lead tab may extend outward from a second uncoated portion of the second substrate where the second active material layer is not disposed. The second lead tab may be electrically connected to a housing. The first lead tab and the second lead tab may extend in opposite directions.

[0082] The first electrode can be used as a cathode. The first substrate can be, for example, aluminum foil, and the first active material layer can include, for example, a transition metal oxide. The second electrode can be used as an anode.

[0083] The second substrate may be, for example, copper foil or nickel foil, and the second active material layer may include, for example, graphite.

[0084] The separator allows lithium ions to move between the first and second electrodes while preventing short circuits between them. The separator can be, for example, a polyethylene membrane, a polypropylene membrane, or a polyethylene-polypropylene membrane.

[0085] The housing can accommodate the electrode assembly and electrolyte, and together with the cover assembly, forms the appearance of the secondary battery LC. The housing may include a body having an approximately cylindrical shape and a bottom attached to one side of the body.

[0086] The inwardly deformed coiled portion can be located at the main body, and the inwardly bent crimped portion can be located at the end of the opening in the main body. The coiled portion prevents the electrode assembly from moving inside the housing and facilitates the positioning of the gasket and cover assembly. The crimped portion securely holds the cover assembly in place by pressing the edge of the cover assembly via the gasket. The housing can be made of, for example, nickel-plated iron.

[0087] The cover assembly can be secured inside the crimping portion by a gasket to seal the housing. The cover assembly may include an upper cover, a safety vent, a lower cover, an insulating member, and a base plate, but embodiments of this disclosure are not limited to these examples, and the cover assembly can be modified in various ways.

[0088] The top cover may be located at the uppermost side of the cover assembly. The top cover may include a terminal portion that protrudes upward and connects to external circuitry. An exhaust port for venting gas may be located around the terminal portion.

[0089] The safety vent may be located below the top cover. The safety vent may include a protrusion that projectes downwards and connects to the base plate. At least one cutout may be located around the protrusion.

[0090] When gas is generated due to overcharging or abnormal operation of the secondary battery LC, the protrusion can deform upwards under pressure and separate from the base plate, while the safety vent can be cut along the notch. The cut safety vent allows gas to escape to the outside of the secondary battery LC, thereby preventing an internal explosion of the secondary battery LC.

[0091] The lower cover may be located below the safety vent. The lower cover may have a first opening for exposing the safety vent and a second opening for venting gas. An insulating member may be located between the safety vent and the lower cover to insulate the safety vent from the lower cover.

[0092] The base plate can be located below the lower cover. The base plate can be fixed to the lower surface of the lower cover to block the first opening of the lower cover, and the protrusion of the safety vent can be fixed to the base plate.

[0093] The first lead connector extracted from the electrode assembly can be fixed to the base plate. Therefore, the top cover, safety vent, bottom cover, and base plate can be electrically connected to the first electrode of the electrode assembly.

[0094] The insulating plate can be positioned below the coiled portion to contact the electrode assembly, and the insulating plate can have a tab opening for withdrawing the first lead tab. The cover assembly, electrically connected to the first electrode via the first lead tab, can face the electrode assembly, with the insulating plate between the cover assembly and the electrode assembly, and the cover assembly can be kept insulated from the electrode assembly by the insulating plate.

[0095] Electrodes are typically fabricated by preparing a slurry of an active material having the desired polarity, coating the slurry onto a current collector, and drying and rolling the current collector. For example, in the electrodes of a secondary battery (LC) manufactured in this way, protruding electrode tabs are attached to the electrode current collector by methods such as welding.

[0096] When the secondary battery LC is a prismatic secondary battery or a pouch-type secondary battery, the secondary battery LC may include an electrode assembly, a first current collector, a first terminal, a second current collector, a second terminal, a housing, and a cover assembly.

[0097] The electrode assembly can be formed by winding or stacking a stack of a first electrode plate, a diaphragm, and a second electrode plate, wherein the stack is formed in a plate shape or a film shape. When the electrode assembly is a wound stack, the winding axis can be parallel to the longitudinal direction of the housing. However, the electrode assembly can be stacked rather than wound, and the shape of the electrode assembly is not limited in this disclosure. For example, the electrode assembly can be a Z-shaped stacked electrode assembly, in which the cathode plate and the anode plate are inserted into both sides of a diaphragm that is bent in a Z-shape.

[0098] One or more electrode assemblies may be stacked such that their long side surfaces are adjacent to each other and can be housed within a housing. The number of electrode assemblies is not limited in this disclosure.

[0099] The first electrode plate of the electrode assembly can be used as the anode, and the second electrode plate can be used as the cathode. The reverse is also possible. The first electrode plate can be formed by coating a first electrode active material, such as graphite or carbon, onto a first electrode current collector plate formed of a metal foil such as copper, a copper alloy, nickel, or a nickel alloy. The first electrode plate may include a first electrode tab (or a first uncoated portion), which is the area on which the first electrode active material is not coated. The first electrode tab can serve as a path for current between the first electrode plate and the first current collector. In some examples, when manufacturing the first electrode plate, the first electrode tab can be formed by cutting it to protrude to one side of the first electrode plate. The first electrode tab can protrude further to that side than the diaphragm without separate cutting.

[0100] The second electrode plate can be formed by coating a second electrode active material, such as a transition metal oxide, onto a second electrode current collector plate formed of aluminum or an aluminum alloy foil. The second electrode plate may include a second electrode tab (or a second uncoated portion), which is the area to which the second electrode active material is not coated. The second electrode tab can serve as a path for current between the second electrode plate and the second current collector. In some examples, when manufacturing the second electrode plate, the second electrode tab can be formed by cutting it to protrude to one side of the second electrode plate. The second electrode tab may protrude further to that side than the diaphragm without requiring a separate cut.

[0101] In some examples, the first electrode tab may be located on the side surface of the left end of the electrode assembly, and the second electrode tab may be located on the side surface of the right end of the electrode assembly. Alternatively, the first electrode tab and the second electrode tab may be located on the same surface in the same direction. As described above, the first electrode tab of the first electrode plate and the second electrode tab of the second electrode plate may be located at two ends of the electrode assembly, respectively.

[0102] In some examples, the electrode assembly may be housed together with the electrolyte within a housing. For instance, in the electrode assembly, a first current collector and a second current collector may be positioned as a first electrode terminal piece welded to and connected to a first electrode plate and a second electrode terminal piece of a second electrode plate.

[0103] Refer again Figure 5 In operation S200, where the electrolyte is injected into the secondary battery, the user can inject the electrolyte into the casing of the secondary battery LC, thereby allowing the electrolyte to contact or be immersed in the electrode assembly.

[0104] The electrolyte for a secondary battery (LC) can include a non-aqueous organic solvent and a lithium salt. The non-aqueous organic solvent serves as a medium through which ions involved in the battery's electrochemical reactions can move. The non-aqueous organic solvent can be a carbonate solvent, an ester solvent, an ether solvent, a ketone solvent, an alcohol solvent, an aprotic solvent, or a combination thereof, and can be used alone or in combination of two or more. For example, when using carbonate solvents, cyclic carbonates and chain carbonates can be mixed and used.

[0105] The electrolyte injected into the secondary battery LC can be an organic electrolyte, and the organic electrolyte can include lithium salts. The organic electrolyte can include high-dielectric-constant solvents and low-boiling-point solvents. The high-dielectric-constant solvent can be at least one of ethylene carbonate, propylene glycol carbonate, butylene glycol carbonate, and γ-butyrolactone. The low-boiling-point solvent can be at least one of dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, dipropyl carbonate, dimethoxyethane, diethoxyethane, and fatty acid ester derivatives. The lithium salt can be at least one of LiPF6, LiBF4, LiClO4, Li(CF3SO2)2, LiCF3SO3, LiSbF6, and LiAsF6. The concentration of the lithium salt can be in the range of 0.1M to 2.0M. When the concentration of the lithium salt is within this range, the electrolyte has suitable conductivity and viscosity, allowing the electrolyte to exhibit excellent electrolyte performance and enabling efficient movement of lithium ions.

[0106] refer to Figure 6 The operation S300 for activating the secondary battery may include an operation S310 for initially charging the secondary battery, an operation S320 for determining whether the SOC of the secondary battery is greater than a preset SOC, and an operation S330 for aging the initially charged secondary battery.

[0107] The operation of activating the secondary battery S300 and the operation of applying ultrasound to the electrolyte S400 can be performed simultaneously. That is, for example, the operation of initially charging the secondary battery S310 and the operation of applying ultrasound to the electrolyte S400 can be performed simultaneously.

[0108] In the initial charging operation S310 of the secondary battery, the user can electrically connect the secondary battery LC to the charging unit 100 to apply a voltage to the secondary battery LC. For example, in the initial charging operation S310 of the secondary battery, the charging unit 100 can apply positive power to the cathode terminal provided in the electrode assembly and apply negative power to the anode terminal to charge the electrode assembly, thereby forming an SEI film on the electrode surface.

[0109] In some embodiments, the operation S310 of initially charging the secondary battery can be performed in a vacuum or low-pressure environment, such that while the secondary battery LC is being initially charged, the gas included in the electrolyte can be discharged to the outside of the secondary battery LC.

[0110] In operation S320, which determines whether the SOC of the secondary battery is greater than a preset SOC, the controller 300 can detect information about the SOC of the secondary battery LC. When the SOC of the secondary battery LC is greater than the preset SOC, the controller 300 can control the drive of the charging unit 100 to stop charging the secondary battery LC. For example, when the SOC of the secondary battery LC is less than the preset SOC, the controller 300 can control the drive of the charging unit 100 or the ultrasonic generator 200 to continuously charge the secondary battery LC until the SOC of the secondary battery LC is greater than the preset SOC, and can continuously apply ultrasonic waves to the secondary battery LC.

[0111] In some embodiments, the aging process S330 of the secondary battery can be a process of storing the secondary battery LC for a specific period of time under preset temperature and / or humidity conditions after initial charging to stabilize internal chemical reactions or optimize the electrical characteristics of a single cell. In some embodiments, the aging process S330 of the secondary battery can be an operation of placing and stabilizing a stacked electrode assembly in which electrolyte is injected. For example, the aging process S330 of the secondary battery can be performed at room temperature for 22 to 26 hours. When the aging time of the secondary battery LC exceeds 26 hours, the manufacturing process may be delayed. When the aging time of the secondary battery LC is less than 22 hours, the electrolyte may not be uniformly impregnated, which may hinder the formation of a uniform SEI film in the subsequent pre-charging process.

[0112] In some cases, continuous aging of secondary battery LCs can be performed at high temperatures. When continuous aging of secondary battery LCs is performed at high temperatures, the SEI film can be more stable and form uniformly with a uniform thickness.

[0113] In this embodiment, the process of aging the secondary battery LC at high temperature can be performed at a temperature of about 30°C to about 45°C for about 12 to 24 hours. When the process is performed within these temperature and time ranges, an appropriate thickness of the SEI film can be maintained, thereby preserving capacity at the start of charging to ensure the capacity of the lithium battery.

[0114] refer to Figure 5 and Figure 6In operation S400 of applying ultrasonic waves to the electrolyte injected into a secondary battery according to an embodiment of the present disclosure, the controller 300 can drive the ultrasonic generator 200 to apply ultrasonic waves to one side of the secondary battery LC. For example, when the secondary battery LC is a cylindrical secondary battery, the controller 300 can adjust the position, orientation, or ultrasonic wave application direction of the ultrasonic generator 200 so that the ultrasonic waves are applied to the center portion of the side surface of the secondary battery LC. As another example, when the secondary battery LC is a pouch-type or prismatic secondary battery, the controller 300 can adjust the position, orientation, or ultrasonic wave application direction of the ultrasonic generator 200 so that the ultrasonic waves are applied to the center portion of the front surface of the secondary battery LC.

[0115] In the operation S400 of applying ultrasound to the electrolyte, the frequency of the ultrasound applied to the electrolyte can be variable. Furthermore, for example, the controller 300 can control the drive of the ultrasound generator 200 to change the frequency of the ultrasound applied from the ultrasound generator 200 to the secondary battery LC according to a preset standard.

[0116] refer to Figure 2 During the activation or formation process, the controller 300 can measure the state of charge (SOC) of the secondary battery LC, which is charged by receiving voltage from the charging unit 100, in real time. The controller 300 can adjust the frequency of the ultrasonic waves applied to the secondary battery LC based on changes in the SOC. For example, the controller 300 can control the drive of the ultrasonic generator 200 such that the frequency of the ultrasonic waves applied to the secondary battery LC is relatively higher when the SOC is less than a preset value than when the SOC is greater than the preset value.

[0117] refer to Figure 2 When the state of charge (SOC) of the secondary battery LC is less than a preset first SOC V1, the controller 300 can control the drive of the ultrasonic generator 200 to adjust the frequency of the ultrasonic waves applied to the secondary battery LC to a first frequency f1. As the SOC of the secondary battery LC gradually increases to be greater than the first SOC V1, the controller 300 can control the drive of the ultrasonic generator 200 to adjust the frequency of the ultrasonic waves applied to the secondary battery LC to a second frequency f2, which is lower than the first frequency f1.

[0118] In the example embodiment, the first SOC V1 can be in the range of 1% to 10% or 2% to 5%, the first frequency f1 can be in the range of 10MHz to 20MHz, and the second frequency f2 can be in the range of 50kHz to 10MHz.

[0119] Refer again Figure 2When the state of charge (SOC) of the secondary battery LC is less than a second SOC (V2) which is greater than the first SOC (V1), the controller 300 can control the drive of the ultrasonic generator 200 to adjust the frequency of the ultrasonic waves applied to the secondary battery LC to a second frequency (f2). Furthermore, when the SOC of the secondary battery LC gradually increases to be greater than the second SOC (V2), the controller 300 can control the drive of the ultrasonic generator 200 to adjust the frequency of the ultrasonic waves applied to the secondary battery LC to a third frequency (f3) which is lower than the second frequency (f2).

[0120] In the example embodiment, the second SOC V2 can be in the range of 10% to 20%, and the third frequency f3 can be in the range of 20kHz to 50kHz.

[0121] refer to Figure 3 According to embodiments of the present disclosure, the controller 300 can adjust the frequency of the ultrasonic waves applied to the secondary battery LC as the activation time of the secondary battery LC increases. For example, the controller 300 can control the driving of the ultrasonic generator 200 such that the frequency of the ultrasonic waves applied to the secondary battery LC when the activation time of the secondary battery LC has not yet reached a preset time is higher than the frequency of the ultrasonic waves applied to the secondary battery LC when the activation time of the secondary battery LC is longer than the preset time.

[0122] As is evident from the foregoing description, in this disclosure, the “activation time” of the secondary battery LC can be the same as the “charging time” during which the secondary battery LC is charged.

[0123] Refer again Figure 3 When the activation time of the secondary battery LC is shorter than the preset first charging time t1, the controller 300 can control the drive of the ultrasonic generator 200 to adjust the frequency of the ultrasonic waves applied to the secondary battery LC to a first frequency f1. When the activation time of the secondary battery LC is longer than the first charging time t1, the controller 300 can control the drive of the ultrasonic generator 200 to adjust the frequency of the ultrasonic waves applied to the secondary battery LC to a second frequency f2, which is lower than the first frequency f1.

[0124] Accordingly, the controller 300 can easily adjust the frequency of the ultrasonic waves applied to the secondary battery LC using only information about the charging time of the secondary battery LC, which increases along with the state of charge (SOC) of the secondary battery LC, without actually measuring the SOC of the secondary battery LC.

[0125] In the example embodiment, the first frequency f1 can be in the range of 10MHz to 20MHz, and the second frequency f2 can be in the range of 50kHz to 10MHz.

[0126] refer to Figure 3When the activation time of the secondary battery LC is shorter than the second charging time t2, which is longer than the first charging time t1, the controller 300 can control the drive of the ultrasonic generator 200 to adjust the frequency of the ultrasonic waves applied to the secondary battery LC to a second frequency f2. When the activation time of the secondary battery LC is longer than the second charging time t2, the controller 300 can control the drive of the ultrasonic generator 200 to adjust the frequency of the ultrasonic waves applied to the secondary battery LC to a third frequency f3, which is lower than the second frequency f2. In an example embodiment, the third frequency f3 can be in the range of 20kHz to 50kHz.

[0127] refer to Figure 4 According to an embodiment of the present disclosure, the operation S400 of applying ultrasound may include applying ultrasound with frequency f1' to the electrolyte for a first time p1, and applying ultrasound with frequency f2' lower than frequency f1' to the electrolyte for a second time p2 shorter than the first time p1.

[0128] The controller 300 can control the drive of the ultrasonic generator 200 so that an ultrasonic wave with frequency f1' is applied to the secondary battery LC for a first time p1, and the controller 300 can control the drive of the ultrasonic generator 200 so that an ultrasonic wave with frequency f2' lower than frequency f1' is applied to the secondary battery LC for a second time p2 shorter than the first time p1.

[0129] In an embodiment, when the SOC of the secondary battery LC is less than a first SOC V1, the controller 300 can perform control to adjust the first frequency f1 to frequency f1'. When the SOC of the secondary battery LC is greater than the first SOC V1 and less than a second SOC V2, the controller 300 can perform control to adjust the frequency f1' to a second frequency f2. When the SOC of the secondary battery LC is greater than the second SOC V2, the controller 300 can perform control to adjust the frequency f1' to a third frequency f3. In an embodiment, frequency f2' can be 0Hz or approximately 0Hz. In some embodiments, the ratio of frequency f1' to frequency f2' can be in the range of 10 to 100. In an embodiment, the ratio of the first time p1 to the second time p2 can be in the range of 3 to 5. For example, when the first time p1 is about 60 seconds, the second time p2 can be in the range of 12 to 20 seconds; when the first time p1 is about 30 seconds, the second time p2 can be in the range of 6 to 10 seconds; and when the first time p1 is about 5 seconds, the second time p2 can be in the range of 1 to 2 seconds.

[0130] Operation S400 of applying ultrasound with a first frequency f1 or operation S400 of applying ultrasound with a second frequency f2 can be repeatedly performed. Accordingly, the stress accumulated in the electrolyte or electrode assembly due to the continuous application of ultrasound during the activation process of the secondary battery LC can be reduced. Furthermore, the impregnation rate of the electrolyte can be increased and side reactions can be reduced. That is, in the method and apparatus for manufacturing a secondary battery according to embodiments of the present disclosure, ultrasound can be applied to one side of the secondary battery LC while charging the secondary battery LC for the activation process, thereby promoting the impregnation of the electrolyte into the electrode assembly and reducing the possibility of side reactions occurring between the electrode assembly and the electrolyte.

[0131] However, the effects that can be achieved through this disclosure are not limited to those described above, and those skilled in the art will clearly understand other technical effects not described herein.

[0132] Although this disclosure has been described by way of example, it is not limited to the disclosed embodiments. Various modifications and variations can be made by those skilled in the art within the scope of the spirit of this disclosure.

[0133] The embodiments described herein are descriptive and do not limit the full scope of this disclosure. The description of features or aspects within each embodiment should generally be considered applicable to other similar features or aspects in other embodiments. While one or more embodiments have been described with reference to the figures, those skilled in the art will understand that various changes in form and detail may be made therein without departing from the spirit and scope of this disclosure.

Claims

1. A method for manufacturing a secondary battery, the method comprising: providing the secondary battery; injecting an electrolyte into the secondary battery; activating the secondary battery into which the electrolyte is injected; and applying ultrasonic waves to the electrolyte in the secondary battery. The activation of the secondary battery and the application of the ultrasonic waves to the electrolyte are simultaneously performed.

2. The method of claim 1, wherein, The application of the ultrasonic waves to the electrolyte is performed while a state of charge of the secondary battery is increased.

3. The method of claim 2, wherein, The activation of the secondary battery includes initial charging of the secondary battery and aging of the secondary battery initially charged, and 4. The method of claim 2, wherein, wherein the application of the ultrasonic waves to the electrolyte is performed while the initial charging of the secondary battery is performed. In the application of the ultrasonic waves to the electrolyte, a frequency of the ultrasonic waves is variable.

5. The method of claim 1, wherein, The frequency of the ultrasonic waves applied to the electrolyte is adjusted according to a state of charge of the secondary battery.

6. The method of claim 5, wherein, When the state of charge of the secondary battery is less than a preset value, the frequency of the ultrasonic waves applied to the electrolyte is adjusted to be higher than the frequency of the ultrasonic waves applied to the electrolyte when the state of charge of the secondary battery is greater than the preset value.

7. The method of claim 6, wherein, The frequency of the ultrasonic waves applied to the electrolyte is adjusted according to an activation time of the secondary battery.

8. The method of claim 5, wherein, When the activation time of the secondary battery is shorter than a preset time, the frequency of the ultrasonic waves applied to the electrolyte is adjusted to be higher than the frequency of the ultrasonic waves applied to the electrolyte when the activation time of the secondary battery is longer than the preset time.

9. The method of claim 8, wherein, The application of the ultrasonic waves to the electrolyte includes:

10. The method of claim 2, wherein, applying ultrasonic waves having a first frequency to the electrolyte for a first time; and applying ultrasonic waves having a second frequency lower than the first frequency to the electrolyte for a second time shorter than the first time. The application of the ultrasonic waves having the first frequency and the application of the ultrasonic waves having the second frequency are repeatedly performed.

11. The method of claim 10, wherein, A ratio of the first time to the second time is 3 to 5.

12. The method of claim 11, wherein, In the application of the ultrasonic waves to the electrolyte, a frequency of the ultrasonic waves applied to the electrolyte is 20 kHz to 20 MHz.

13. The method of claim 1, wherein, 14.An apparatus for manufacturing a secondary battery, the apparatus comprising: a charging unit electrically connected to the secondary battery and configured to charge the secondary battery, wherein an electrolyte is provided in the secondary battery; an ultrasonic wave generator configured to apply ultrasonic waves to one side of the secondary battery; and a controller configured to control driving of the ultrasonic wave generator while the secondary battery is charged. The controller is configured to control the driving of the ultrasonic wave generator to adjust a frequency of the ultrasonic waves applied to the secondary battery.

15. The apparatus of claim 14, wherein, The controller is capable of measuring a state of charge of the secondary battery and adjusting the frequency of the ultrasonic waves applied to the secondary battery according to the state of charge of the secondary battery.

16. The apparatus of claim 15, wherein, ​ 17. The apparatus of claim 16, wherein, The controller adjusts the frequency of the ultrasonic waves applied to the secondary battery to be higher when the charge state of the secondary battery is less than a preset value than when the charge state of the secondary battery is greater than the preset value.

18. The apparatus of claim 15, wherein, The controller adjusts the frequency of the ultrasonic waves applied to the secondary battery according to a charge time of the secondary battery.

19. The apparatus of claim 18, wherein, The controller adjusts the frequency of the ultrasonic waves applied to the secondary battery to be higher when the charge time of the secondary battery is shorter than a preset time than when the charge time of the secondary battery is longer than the preset time.

20. The apparatus of claim 14, wherein, The frequency of the ultrasonic waves applied to the secondary battery by the ultrasonic wave generator is 20 kHz to 20 MHz.

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