CN116745947A - Apparatus for manufacturing secondary battery and method for manufacturing secondary battery using the same - Google Patents

Abstract

The present invention relates to an apparatus for manufacturing a secondary battery and a method for manufacturing a secondary battery using the same, and more particularly, to an apparatus for manufacturing a secondary battery capable of improving non-bonding areas of an electrode and a separator inside an electrode unit and non-bonding areas of an electrode unit and a separator inside an electrode assembly, and a method for manufacturing a secondary battery using the same. The present invention provides an apparatus for manufacturing a secondary battery, the apparatus including a pressing part configured to press a stack body alternately provided with electrodes and separators, wherein the pressing part includes: a main pressing portion configured to press the entire surface of the stack; and a sub-pressing portion including a drum portion configured to press a partial surface of the stack body where an edge portion of the electrode active material layer provided on each of the electrodes is located, of an entire surface of the stack body, wherein the drum portion includes: a main body part having a rotation shaft; and an elastic portion provided on an outer peripheral surface of the main body portion and configured to press a partial surface of the stacked body.

Description

Apparatus for manufacturing secondary battery and method for manufacturing secondary battery using the same

Technical Field

Cross Reference to Related Applications

The present application claims the benefit of priority from korean patent application No. 10-2021-0124577, filed on month 9 of 2021, and korean patent application No. 10-2022-015228, filed on month 13 of 2022, which are incorporated herein by reference in their entirety.

Technical Field

The present application relates to an apparatus for manufacturing a secondary battery and a method for manufacturing a secondary battery using the same, and more particularly, to an apparatus for manufacturing a secondary battery capable of improving non-bonding areas of an electrode and a separator inside an electrode unit and non-bonding areas of an electrode unit and a separator inside an electrode assembly, and a method for manufacturing a secondary battery using the same.

Background

When AC power to be supplied to a building is not available or DC power is required according to a living environment surrounded by various electric and electronic devices, a battery (cell) that generates electric power through a physical or chemical reaction to supply the generated electric power to the outside is used.

Among these batteries, primary and secondary batteries, which are chemical batteries using chemical reactions, are generally used. Primary batteries are consumable batteries, which are collectively referred to as dry cells. In addition, the secondary battery is a rechargeable battery manufactured by using a material in which a redox process between a current and a substance can be repeated a plurality of times. Charging is performed when a reduction reaction is performed on the material by an electric current, and discharging is performed when an oxidation reaction is performed on the material. This charge-discharge is repeatedly performed to generate electric power.

Here, in a lithium ion battery among secondary batteries, an electrode slurry (slurry) in which an active material, a conductive material, and a binder are mixed may be applied to a positive electrode conductive foil and a negative electrode conductive foil at a predetermined thickness to manufacture an electrode, and a separator may be interposed between the two conductive foils to manufacture an electrode unit.

In addition, secondary batteries are classified according to their structures. For example, the secondary battery may be classified into: a cylindrical secondary battery in which a long sheet-type electrode unit is wound in the form of a large jelly roll (jellyroll) a plurality of times with a separator sheet therebetween to manufacture an electrode assembly, and then the manufactured electrode assembly is accommodated in a cylindrical can such that the can is sealed; and a pouch-type secondary battery in which electrode units each having a predetermined size are stacked and folded with a separator therebetween to manufacture an electrode assembly, and then the manufactured electrode assembly is received in a pouch such that the pouch is sealed.

When manufacturing an electrode, the electrode paste is unevenly applied to the conductive foil due to the viscosity of the electrode paste, causing a difference in the coating thickness of the electrode paste. The difference in coating thickness of the electrode paste is formed in a non-bonding region between the electrode and the separator inside the electrode unit manufactured by including the electrode. Further, since the pouch-type secondary battery is manufactured by stacking the electrode units on the separator sheet, the non-bonding region is formed inside the electrode assembly including the electrode units. The non-binding region as described above has a problem in that lithium is precipitated due to the interfacial resistance of the negative electrode, thereby increasing the resistance of the electrode.

Disclosure of Invention

Technical problem

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an apparatus for manufacturing a secondary battery capable of improving non-bonding areas of an electrode and a separator inside an electrode unit and non-bonding areas of an electrode unit and a separator inside an electrode assembly, and a method for manufacturing a secondary battery using the same.

Technical proposal

The present invention may include an apparatus for manufacturing a secondary battery, the apparatus including a pressing part configured to press a stack body alternately provided with electrodes and separators, wherein the pressing part includes: a main pressing portion configured to press an entire surface of the stack; and a sub-pressing portion including a drum portion configured to press a partial surface of the stack body where an edge portion of an electrode active material layer provided on each of the electrodes is located, of an entire surface of the stack body, wherein the drum portion includes: a main body portion having a rotation axis; and an elastic portion provided on an outer peripheral surface of the main body portion and configured to press the partial surface of the stacked body.

The edge portion of the electrode active material layer may have a curved surface whose height gradually decreases toward an end thereof, and the drum portion may be configured to press the edge portion and the separator such that the edge portion and the separator of the electrode active material layer corresponding to each other are bonded to each other.

The elastic portion may be provided to be elastically deformable.

The elastic part may have an inner space, and air (air) or fluid may be filled into the inner space to maintain a preset pressure.

The elastic portion may be made of a deformable synthetic resin, and the synthetic resin may be provided as silicone rubber (silicone rubber).

The shape of the sub-pressing part may be deformed only when the partial surface is pressed.

The apparatus may further include a pressure detecting portion configured to detect a pressure applied to the partial surface of the stack by the sub-pressing portion.

The pressure detecting portion may include: a sensor portion that senses pressure; and a display section that displays the pressure sensed by the sensor section.

The sensor portion may be disposed to face the sub-pressing portion with the partial surface of the stack being interposed therebetween.

The stack may include an electrode tab connected to the electrode, and the sub-pressing part may press the partial surface of the stack where the edge portion of the electrode active material layer disposed on the electrode connected to the electrode tab is located.

The sub-pressing portion may be disposed on at least one of a front side and a rear side of the main pressing portion.

The apparatus may further include a heating part disposed behind the pressing part to apply heat to the stack body stacked with the electrode and the separator, wherein the sub-pressing part may be disposed between the heating part and the main pressing part.

The edge portions may be located at each of both end portions of the electrode active material layer provided on each of the electrodes, and the drum portions may be provided in pairs, a pair of drum portions respectively pressing the partial surfaces of the stack body where the edge portions located at both end portions of the electrode active material layer are located.

The edge portions may be located at both end portions of the electrode active material layer provided on the electrode, respectively, and the drum portion may be configured to press a surface including the partial surface of the stack where the edge portion located at each of the both end portions of the electrode active material layer is located.

The sub-pressing part may further include a pressure sensor configured to measure a pressure of air (air) or fluid filled into the inner space of the elastic part.

The sub-pressing portion may further include an injection portion configured to inject air (air) or fluid into an inner space of the elastic portion through the body portion.

The present invention may include a method of manufacturing a secondary battery, the method including: an electrode unit manufacturing step of manufacturing an electrode unit in which electrodes and separators are alternately stacked; an electrode assembly manufacturing step of providing a separator sheet between the plurality of electrode units manufactured in the electrode unit manufacturing step to manufacture an electrode assembly; and a pressing process of pressing the electrode assembly, wherein the electrode unit manufacturing process includes: a stacking process of alternately disposing the separator and the electrode to form a stack; a bonding process of bonding each separator and each electrode provided in the stack to each other; wherein the bonding process comprises: an entire surface pressing step of pressing an entire surface of the stacked body; and a first partial surface pressing process of pressing a partial surface of the stack where an edge portion of an electrode active material layer provided on the electrode is located, out of the entire surface of the stack.

The electrode assembly pressing process may include: a second entire surface pressing process of pressing an entire surface of the electrode assembly; and a second partial surface pressing process of pressing a partial surface of the electrode assembly where an edge portion of an electrode active material layer provided on the electrode is located, of the entire surface of the electrode assembly.

Advantageous effects

The apparatus for manufacturing a secondary battery according to the present invention and the method for manufacturing a secondary battery using the same may have the following advantages: the partial surface of the entire surface of the stack where the edge portions of the electrode active material layers disposed on the electrodes of the stack are located is pressed using the sub-pressing part to improve the non-bonding region inside the stack.

In addition, the apparatus for manufacturing a secondary battery according to the present invention may have the following advantages: by using the sub-pressing part including the elastic part, it is possible to correspond to various sizes and shapes of partial surfaces in the entire surface of the stack without replacing the sub-pressing part.

Further, the apparatus for manufacturing a secondary battery according to the present invention may have the following effects: a pressure detecting portion is included to detect a pressure at which the sub-pressing portion presses the stacked body, so that workability is easily managed according to a model of the stacked body and a processing environment based on the detected pressure.

Drawings

Fig. 1a is a perspective view of a stack according to the invention.

Fig. 1b is a side view illustrating a configuration when the stacked body of fig. 1a is viewed from one side.

Fig. 2 is a plan view illustrating a configuration when the apparatus for manufacturing a secondary battery according to embodiment 1 of the present invention is viewed from above and below.

Fig. 3 is a side view illustrating a configuration when the apparatus for manufacturing a secondary battery of fig. 2 is viewed from one side.

Fig. 4a is a detailed side view illustrating a side surface of a sub-pressing part in the apparatus for manufacturing a secondary battery of fig. 2.

Fig. 4b is a front view illustrating a drum part of the sub-pressing part in the apparatus for manufacturing a secondary battery of fig. 2.

Fig. 4c is a side view illustrating a drum part of the sub-pressing part in the apparatus for manufacturing a secondary battery of fig. 2.

Fig. 5a is a detailed enlarged view illustrating a state in which an elastic part presses a stack having a shape in the apparatus for manufacturing a secondary battery of fig. 2.

Fig. 5b is a detailed enlarged view illustrating a state in which an elastic part presses a stack having another shape in the apparatus for manufacturing a secondary battery of fig. 2.

Fig. 5c is a detailed enlarged view illustrating a state in which an elastic part presses a stack having yet another shape in the apparatus for manufacturing a secondary battery of fig. 2.

Fig. 5d is a detailed enlarged view illustrating a state in which an elastic part presses a stack according to another embodiment in the apparatus for manufacturing a secondary battery of fig. 2.

Fig. 6 is a detailed perspective view illustrating the construction of the sub-pressing part and the pressure detecting part in the apparatus for manufacturing the secondary battery of fig. 2.

Fig. 7 is an image illustrating a result obtained by comparing non-bonded regions of a bicell (bi-cell) manufactured by an apparatus a for manufacturing a secondary battery according to the related art and an apparatus b for manufacturing a secondary battery according to the present application.

Detailed Description

Hereinafter, preferred embodiments of the present application will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present application. This application may, however, be embodied in many different forms and is not limited or restricted by the examples below.

For the purpose of clearly explaining the present application, detailed descriptions of related known techniques, which are not related to the description, or which may unnecessarily obscure the gist of the present application, are omitted, and in the present application, reference numerals are added to the parts in each drawing. In this case, the same or similar reference numerals are assigned to the same or similar elements throughout the application.

Furthermore, the terms or words used in the present specification and claims should not be construed restrictively as ordinary meanings or dictionary-based meanings, but should be construed as meanings and concepts conforming to the scope of the present invention based on the principle that the inventor is able to properly define terms so as to describe and explain his or her invention in the best way.

The present invention may provide an apparatus for manufacturing a secondary battery, the apparatus including a pressing part 100, the pressing part 100 pressing a stack 10 stacked with an electrode 101 and a separator 102.

First, the stack 10 may be configured such that the electrode 101 and the separator 102 are stacked, and may have various configurations. Here, the stacked body 10 may be an electrode unit in which the electrode 101 and the separator 102 are stacked, that is, a unit cell, may refer to any one of a bi-cell (bi-cell), a single cell (mono-cell), and a full cell (full-cell), and may also refer to an electrode assembly in which a plurality of electrode units (unit cells) in which the electrode 101 and the separator 102 are stacked and the separator sheet 20 are stacked.

Referring to fig. 1b, the electrode 101 includes an electrode current collector 1011 and an electrode active material layer 1012 applied on a surface of the electrode current collector 1011.

Here, the electrode assembly may have any structure as long as the electrode assembly has a structure in which a plurality of electrode units and separator sheets are stacked. As an example, the electrode assembly may have a structure in which a plurality of electrode units are arranged or disposed on a membrane sheet. As another example, the electrode assembly may have a structure in which a plurality of electrode units are arranged or disposed on a separator sheet, and then the electrode units and the separator sheet are alternately stacked and folded.

Here, the stack 10 may be pressed by a pressing part 100 to be described later so as to bond the electrode to the separator and the electrode unit to the separator sheet. Here, the entire surface of the stack 10 disposed to face the pressing portion 100 and to be pressed may be defined as the entire surface 11.

As described above, since the electrode paste is unevenly applied on the electrode current collector (e.g., conductive foil), the entire surface 11 may have a height difference. In particular, since a surface formed with a relatively low height in the entire surface 11 is difficult to perform pressing during the pressing process, the surface may remain as a non-bonding region between the electrode and the separator or between the electrode unit and the separator sheet, thereby causing precipitation of lithium at the interface of the negative electrode.

In more detail, as shown in fig. 1a to 1b, the entire surface 11 of the stack 10 may include a partial surface 12 and the remaining surface 13, the partial surface 12 including a surface formed with a relatively low height among the entire surface 11, and the remaining surface 13 being formed with a uniform height due to the electrode paste being uniformly applied on the electrode current collector. In the drawings, the dashed lines shown in the stack 10 are used to distinguish the partial surface 12 from the remaining surface 13, rather than meaning that the internal structure of the stack 10 is separated.

Here, the partial surface 12 may be a surface formed with a relatively low height surface due to less application of electrode paste on the electrode current collector, among the entire surface 11 including the stack 10, and may have various configurations.

As an example, the partial surface 12 may be a surface on which a height difference is formed, and as shown in fig. 1b, the partial surface 12 may include a first partial surface 12a formed with a relatively low height, and a second partial surface 12b formed with a height higher than that of the first partial surface 12a, among the entire surface 11.

Here, the first partial surface 12a may be a surface formed with a relatively low height in the entire surface 11, and may also be a region of the stack 10 where the edge portion 1013 of the electrode active material layer 1012 provided on the electrode 101 is located. The edge portion 1013 of the electrode active material layer 1012 is formed as a curved surface whose height decreases toward the end as the electrode slurry flows downward, and the surface of the stack 10 having the edge portion may have a lower height due to the edge portion 1013 as the curved surface. Thus, a non-bonded state is maintained between the edge portions 1013 of the electrode active material layers 1012 corresponding to each other and the separator 102. The present invention is technically characterized by bonding between the edge portion 1013 of the electrode active material layer and the separator 102 which are not bonded to each other.

Further, the second partial surface 12b may be a surface formed higher than the first partial surface 12a and may be formed in various directions with respect to the first partial surface 12a according to the size of each model of the stack 10 and the degree of non-uniform application of the electrode paste within the stack 10.

For example, as shown in fig. 1b, the second partial surface 12b may be formed between the first partial surface 12a and the remaining surface 13. However, the formation of the second partial surface 12b is not limited thereto, and may be formed in various manners, such as being formed to be surrounded by the first partial surface 12a or to surround the first partial surface 12a.

As another example, the partial surface 12 may be constituted only by the first partial surface 12a having a relatively low height out of the entire surface 11.

The partial surface 12 may be located on any portion of the stack 10.

For example, as the length of the stack 10 increases, the electrode paste is less likely to reach the edges of the electrode current collector when applied, and thus, the partial surface 12 may be positioned corresponding to the edges of the stack 10.

In particular, the partial surface 12 may be positioned corresponding to an edge region of the stack 10 on which the electrode tab 14 is disposed, among edge regions of the stack 10.

In the case where two electrodes are manufactured by applying electrode paste to a central portion of one electrode current collector and drying and then cutting the central portion during electrode manufacturing, it is expected that the electrode paste is sufficiently applied to an edge region of the stack 10 initially corresponding to the central portion of the electrode current collector, but it is understood that the edge region of the electrode current collector on which the electrode tab 14 is disposed is easy for the electrode paste to reach relatively less.

Here, the electrode tab 14 may be formed on the electrode current collector through a notching (notching) process before applying the electrode paste, or may be attached to any portion of the electrode current collector after applying the electrode paste so as to be connected to the electrode.

The pressing part 100 may be configured to press the stack 10, and may have various configurations.

In particular, as shown in fig. 2 and 3, the pressing part 100 according to the present invention may include: a main pressing portion 110, the main pressing portion 110 pressing the entire surface 11 of the stack 10; and a sub-pressing part 120, the sub-pressing part 120 pressing the partial surface 12 of the stack 10.

Here, the main pressing portion 110 may be configured to press the entire surface 11 of the stack 10, and may have various configurations.

For example, the main pressing part 110 may be provided as a roller (roller) that presses the stack 10 while rotating, or a press (press) that presses the stack 10 while moving the stack 10 in the up-down direction.

Here, when the stack 10 is an electrode unit, the main pressing part 110 may be provided as a roller, and when the stack 10 is an electrode assembly, the main pressing part 110 may be provided as a press (press).

The sub-pressing part 120 may be configured to press the partial surface 12 of the stack 10, and may have various configurations.

In more detail, the sub-pressing part 120 may be disposed on at least one of the front side and the rear side of the main pressing part 110 to press the partial surface 12 of the stack 10 before pressing the entire surface 11 of the stack 10 and/or after pressing the entire surface 11. Thus, the sub-pressing part 120 may press the partial surface 12 where the edge portions 1013 of the electrode active material layers 1012 provided on the electrode 101 are located to bond the non-bonding regions of the stack 10, that is, the non-bonding regions between the edge portions 1013 of the electrode active material layers and the separator 102 corresponding to each other. The direction toward the moving direction of the stacked body 10 on the conveyor belt may be referred to as a front side, and the direction opposite to the front side may be referred to as a rear side.

Further, as shown in fig. 3, the sub-pressing part 120 may include a drum part 121 that presses the partial surface 12 of the stack 10 where the edge part 1013 of the electrode active material layer provided on the electrode is located, of the entire surface of the stack 10.

The drum 121 may be configured to press the partial surface 12 of the stack 10 while rotating, and may have various configurations.

In more detail, since the stacks 10 are formed in various lengths and widths for each model, and the regions to which the electrode paste is unevenly applied are irregularly formed for each stack 10, the surface region having a relatively low-height surface (e.g., the first partial surface 12 a) in the entire surface 11 of the stack 10 may be formed in various sizes for each individual stack 10.

Here, when the drum part 121 of the sub-pressing part 120 is made of only hard material (e.g., steel), and thus the shape of the partial surface 12 is not deformed during pressing, the drum part 121 cannot respond to various sizes and shapes of surfaces formed with relatively low heights. Thus, in consideration of such a structure of the user, an inconvenience of frequently replacing the sub-pressing part 120 may occur.

In the present invention, the drum part 121 may be provided, and the drum part 121 can respond to various changes of the partial surface 12 of the stack where the edge part 1013 of the electrode active material layer is located in the entire surface 11 of the single stack 10 without replacing the sub-pressing part 120 or the drum part 121 provided in the sub-pressing part 120, and thus, hereinafter, the drum part 121 may be described in detail.

Here, as shown in fig. 4a to 4c, the drum part 121 may include a body part 121a having a rotation shaft 122 and an elastic part 121b provided to be fixedly coupled along an outer circumferential surface of the body part 121a so as to be elastically deformed.

Here, the body portion 121a may be configured to be coupled to the rotation shaft 122, and may have various configurations.

As shown in fig. 5a, in the drum part 121 having such a configuration, when the body part 121a is rotated by the rotation shaft 122, the elastic part 121b may interlock with the body part 121a while rotating to press the partial surface 12 of the stack 10 where the edge part 1013 of the electrode active material layer is located. Here, the elastic part 121b may be deformed according to the shape of the stack 10 deformed when the partial surface 12 of the stack 10 is pressed to stably press the partial surface 12 of the entire stack 10, in particular, to bond the non-bonding regions between the edge portions 1013 of the electrode active material layers and the separator 102 corresponding to each other.

More specifically, the main body portion 121a may be configured to receive a rotational force from the rotation shaft 122 to rotate the drum portion 121, and may have various configurations. For example, the body portion 121a may have a cylindrical barrel shape, a wheel (wheel) shape having a plurality of spokes, or the like.

Here, the elastic portion 121b may be provided to be fixedly coupled along the outer circumferential surface of the body portion 121a so as to be elastically deformable, and may have various configurations.

That is, as shown in fig. 4a to 4c, the elastic part 121b has an inner space 121c, and a structure in which air (air) or fluid is filled to maintain a preset pressure is provided in the inner space 121 c. For example, the elastic portion 121b may have a shape of a bicycle wheel filled with air.

Hereinafter, the case where the elastic portion 121b corresponds to the partial surface of the stack where the edge portion of the electrode active material layer is located in the entire surface 11 will be described in detail. Here, the width of the partial surface 12, the width of the first partial surface 12a, and the width of the drum 121, which will be described later, can be understood as widths in which the traveling direction of the conveyor belt of the stack 10 is the length direction.

Specifically, the elastic portion 121b may have an elastic material capable of elastically deforming the shape of the pressing surface when the partial surface 12 is pressed, and thus, the drum portion 121 may respond to various changes in the partial surface 12 of the stack 10 in which the edge portion 1013 of the electrode active material layer is located, of the entire surface 11.

As an example, as shown in fig. 5a, when the drum part 121 presses a partial surface of the stack where the edge part of the electrode active material layer 1012 is located, the elastic part 121b may deform the pressing surface of the elastic part 121b pressing the partial surface 12b into a stepped shape in response to the shape of the partial surface 12. Accordingly, the sub-pressing part 120 may press all portions of the partial surface 12 including the first partial surface 12a and the second partial surface 12 b.

As another example, as shown in fig. 5b, in the case of the stack 10 in which two electrode tabs 14 are drawn in two directions of an electrode, respectively, edge portions 1013 of electrode active material layers 1012 may be located at each of two end portions of the electrode active material layers disposed on the electrode, respectively, and thus, the drum portions 121 may be disposed in pairs to press the partial surface 12 of the stack 10 where the edge portions 1013 located at each of the two end portions of the electrode active material layers are located. That is, the pair of drum portions 121 may press the partial surfaces 12 located on both sides of the stacked body, respectively.

In particular, when the width of the partial surface 121 is larger than the width of the drum portion 121, the pressing surface of the elastic portion 121b may be spread in the width direction of the partial surface 12 to press all portions of the partial surface 12.

As another example, in the drum 121, as shown in fig. 5c, in the case of the stack 10 in which two electrode tabs 14 are respectively drawn out in both directions of the electrode, the drum 121 may be provided in pairs to press the entire surface including the partial surface 12 of the stack 10 where the edge portion 1013 at each of both ends of the electrode active material layer is located. That is, one drum 121 may press the entire surface including the partial surface of the stack where the edge portion is located.

As another example, as shown in fig. 5d, the sub-pressing part may be provided to correspond to each of the top and bottom surfaces of the stack 10, and thus the upper and lower parts of the partial surface 12 of the stack may be simultaneously pressed. Here, the sub-pressing portion provided below the stack is referred to as a lower sub-pressing portion 120', and the sub-pressing portion provided above the stack is referred to as an upper sub-pressing portion 120'. That is, in a state where the lower sub-pressing part 120″ is supported on the lower portion of the partial surface 12 of the stack 10, the upper sub-pressing part 120' presses the upper portion of the partial surface of the stack. As a result, the partial surface of the stack disposed between the upper and lower sub-pressing parts is pressed, thereby more effectively pressing the partial surface of the stack 10 where the edge portion 1013 at each of the both end portions of the electrode active material layer is located.

The elastic portion 121b may have various materials capable of elastic deformation. For example, the elastic portion 121b may be made of a deformable synthetic resin, and the synthetic resin may have a material including any one of silicone rubbers (silicone rubbers).

The shape of the elastic portion 121b of the sub-pressing portion 120 is deformable only when pressing a partial surface. Further, the elastic portion 121b may have various structures.

As an example, the elastic portion 121b may have a pad structure made of only an elastic material and have a predetermined thickness. As another example, the elastic part 121b may have an inner space, and a tire structure in which air (air) or fluid is filled to maintain a preset pressure may be provided in the inner space.

Here, the preset pressure may be a predetermined pressure value that allows the elastic portion 121b to elastically deform together with the pressing of the partial surface 12.

Here, the preset pressure may be variously set by the user according to the material and size of the elastic part 121b, and the sub-pressing part 120 may be adjusted by receiving feedback of a pressure value pressing the partial surface 12 of the stack 10 through a pressure detecting part 300, which will be described later.

Further, the sub-pressing part 120 may further include a pressure sensor 123 measuring the pressure of air or fluid filled in the inner space of the elastic part 121 b. The pressure sensor 123 may be disposed in a through hole formed in the body part 121a and connected to the inside of the elastic part 121 b. Therefore, even from the outside, the internal pressure of the elastic portion 121b can be easily checked.

Further, the sub-pressing part 120 may further include an injection part 124 injecting air (air) or fluid into the inner space of the elastic part 121b through the body part 121a. Therefore, when the internal pressure of the elastic portion 121b is low or high, air or fluid may be injected or discharged through the injection portion 124 so as to be kept constant. The sub-pressing part 120 may have any configuration as long as the shape is deformed when the partial surface 12 is pressed, and may not be limited to the case where the above-described elastic part 121b is provided.

The rotation shaft 122 may be configured to rotate the drum 121 by being coupled thereto, and may have various configurations.

For example, one end of the rotation shaft 122 may be connected to the driving motor to receive the rotation force, and thus, the rotation force of the driving motor may be transmitted to the body portion 121a. Further, the rotation shaft 122 may include a bearing (not shown) disposed around an outer circumferential surface of the rotation shaft 122 between the rotation shaft 122 and the body portion 121a.

The apparatus for manufacturing a secondary battery according to the present invention may further include a pressure detecting part 300 as shown in fig. 6.

Here, the pressure detecting part 300 may be configured to detect the pressure applied to the partial surface 12 of the stack 10 by the sub-pressing part 120, and may have various configurations.

That is, in the apparatus for manufacturing a secondary battery according to the present invention, the user may detect the pressure of pressing the stack 10 by the sub-pressing part 120 through the pressure detecting part 300, thereby managing workability according to the model of the stack and the processing environment by using data of the pressure applied to the model of the stack 10 and the processing environment.

The pressure detecting portion 300 may be provided at various positions. For example, the pressure detecting portion 300 may be disposed at a position corresponding to the sub-pressing portion 120 below the conveyor belt.

Further, as shown in fig. 6, the pressure detecting part 300 may include a sensor part 310 sensing pressure, and a display part 320 displaying the pressure sensed by the sensor part 310.

Here, the sensor portion 310 may be configured to sense pressure, and may have various configurations.

That is, the sensor part 310 may include a mechanical, electronic, or semiconductor type pressure sensor sensing pressure, and various types of pressure sensors may be used according to a desired pressure range and pressure measurement environment.

Further, the sensor portion 310 may be disposed at various positions. However, in order to measure the pressure applied to the partial surface 12, as shown in fig. 6, when the sub-pressing part 120 presses the partial surface 12, the sensor part 310 may be preferably disposed to face the sub-pressing part 120 with the partial surface 12 of the stack 10 interposed therebetween. That is, the sensor portion 310 may be disposed on a line through which the partial surface 12 of the stack 10 passes.

The display part 320 may be configured to display the pressure sensed by the sensor part 310, and may have various configurations.

That is, the display portion 320 may have any configuration as long as the display portion 320 is configured to provide the pressure data sensed by the sensor portion 310 to the user, for example, the display portion 320 may include a display (display) device capable of outputting the pressure data as an image.

The apparatus for manufacturing a secondary battery according to the present invention may further include a heating part 200, the heating part 200 applying heat to the stack 10 stacked with the electrode and the separator.

Here, the heating part 200 may be configured to be disposed behind the pressing part 100 so as to apply heat to the stack 10 stacked with the electrode and the separator, and may have various configurations. As described above, the rear may refer to a direction opposite to a direction in which the stack 10 travels on the conveyor belt.

In more detail, the heating part 200 may be disposed behind the pressing part 100 to apply heat to the stack 10 before the pressing part 100 presses the stack 10. That is, as the temperature of the stack 10 increases, the bonding between the electrode and the separator may be improved, and wrinkles formed on the electrode, the separator, and the separator sheet inside the stack during the manufacturing process may be improved.

Here, the stack 10 may be heated to a temperature higher than room temperature. Here, the meaning of room temperature refers to a temperature range referred to in the art as "room temperature". In other words, room temperature refers to the temperature of a laboratory or the like, in particular, it is an expression of a temperature condition used when no temperature is specified or controlled to perform an experiment or when a sample and a substance remain in an indoor space, and refers to an indoor air temperature. Typically, it is a temperature at which a person lives comfortably, and is typically about 15 ℃ to 20 ℃.

As described above, the sub-pressing part 120 may be disposed at various positions, but when the sub-pressing part 120 presses the partial surface 12 in a state in which the stack 10 is heated, the non-coupling region inside the stack 10 may be more effectively improved, and thus, as shown in fig. 2 to 3, the sub-pressing part 120 may be preferably disposed between the heating part 200 and the main pressing part 110.

Hereinafter, a method of manufacturing a secondary battery using the apparatus for manufacturing a secondary battery according to the present invention will be described.

The method of manufacturing a secondary battery according to the present invention includes: an electrode unit manufacturing step of manufacturing an electrode unit in which an electrode and a separator are stacked; an electrode assembly manufacturing step of manufacturing an electrode assembly in which a plurality of electrode units and a separator sheet manufactured in the electrode unit manufacturing step are stacked; and an electrode assembly pressing step of pressing the electrode assembly.

Here, the electrode unit manufacturing process may be a process of manufacturing an electrode unit in which the electrode 101 and the separator 102 are stacked, and may be performed in various ways.

For example, the electrode unit manufacturing process may include: a stacking process of stacking the electrodes 101 on the separator 102 to form a stack 10; and a bonding step of bonding the separator and the electrode in the stack 10.

Here, the stacking process may be a process of stacking the electrode 101 on the separator 102 to form the stack 10, and may be performed in various ways.

Here, the electrode 101 includes an electrode current collector 1011, and an electrode active material layer 1012 applied on the electrode current collector 1011. That is, the electrode 101 may be manufactured as a positive electrode or a negative electrode by applying an electrode paste on an electrode current collector (conductive foil) 1011 such that the electrode paste is applied on the electrode current collector 1011, and a separator may be interposed between the electrodes. However, in the electrode manufacturing process, the electrode paste may be unevenly applied on the electrode current collector. That is, the electrode paste is irregularly applied on the edge portion 1013 of the electrode active material layer 1012 applied on the electrode, and thus, the edge portion 1013 of the electrode active material layer 1012 has a curved surface whose height gradually decreases toward the end thereof.

The bonding process may be a process of bonding the separator in the stack to the electrode, and may be performed in various ways.

For example, the bonding process may include: a first entire surface pressing step of pressing the entire surface of the stack 10; and a first partial surface pressing process of pressing the partial surface 12 having the height difference in the stack.

Here, the first entire surface pressing process may be a process of pressing the entire surface 11 of the stack 10, and may be performed in various ways.

Here, the first entire surface pressing process may be performed by pressing the entire surface 11 of the stack 10 by the above-described main pressing portion 110. However, since the electrode paste is unevenly applied on the electrode current collector, a height difference is generated over the entire surface of the stack 10, and a non-bonding region may be generated on the partial surface 12 of the stack where the edge portion of the electrode active material layer is located in the entire surface (see fig. 1 b).

The first partial surface pressing process may be a process of pressing the partial surface 12 of the stack 10 where the edge portion 1013 of the electrode active material layer 1012 is located, and may be performed in various ways.

Specifically, the first partial surface pressing process may be performed by pressing the partial surface 12 of the stack 10 by the sub-pressing part 120. Here, the detailed configuration and effects of the sub-pressing part 120 may be cited from the above description.

That is, in the first partial surface pressing process, the partial surface 12 of the stack 10 may be additionally pressed to bond the edge portion 1013 of the electrode active material layer of the stack with the non-bonding region between the separator 102. Here, the first partial surface pressing process may be performed not only after the first entire surface pressing process is performed, but also before the first entire surface pressing process is performed.

The electrode assembly manufacturing process may be a process of manufacturing an electrode assembly in which a plurality of electrode units and separator sheets manufactured in the electrode unit manufacturing process are stacked, and may be performed in various manners. Here, the electrode assembly may also be understood as a configuration corresponding to the above-described stacked body 10, but in order to distinguish from the above-described electrode units, the configuration will hereinafter be described as an electrode assembly.

Specifically, in the electrode assembly manufacturing process, the electrode units manufactured in the above-described electrode unit manufacturing process may be arranged side by side on the separator to manufacture the electrode assembly, or after the electrode units are arranged side by side on the separator, the separator may be folded such that the electrode units and the separator are alternately stacked, thereby manufacturing the electrode assembly.

However, in the case of an electrode unit in which a non-bonding region is generated between the electrode and the separator, a specific region of the electrode unit may have a relatively low height compared to other regions. Therefore, when the electrode assembly is manufactured, if the electrode units are arranged and stacked in parallel in one direction, a non-bonding region may be formed between the electrode units and the separator sheet, and a surface disposed at a relatively low height among the entire surface of the electrode assembly may be formed.

The electrode assembly pressing process may be a process of pressing the electrode assembly, and may be performed in various ways.

For example, the electrode assembly pressing process may include: a second entire surface pressing process of pressing an entire surface of the electrode assembly; and a second partial surface pressing step of pressing a partial surface of the electrode assembly, which forms a height difference on the outer surface.

Here, the second entire surface pressing process may be a process of pressing the entire surface of the electrode assembly, and may be performed in various ways.

Here, the second entire surface pressing process may be performed by pressing the entire surface of the electrode assembly by the above-described main pressing part 110. However, since the height difference is generated over the entire surface of the electrode assembly as described above, the non-bonding region may be generated on a partial surface including a surface having a relatively low height among the entire surface.

The second partial surface pressing process may be a process of pressing a partial surface forming a height difference on the outer surface of the electrode assembly, and may be performed in various ways.

Specifically, the second partial surface pressing process may be performed by pressing the partial surface of the electrode assembly where the edge portion of the electrode active material layer is located by the sub-pressing part 120. Here, the detailed configuration and effects of the sub-pressing part 120 may be cited from the above description.

That is, in the second partial surface pressing process, the non-bonding region of the electrode assembly may be improved by additionally pressing the partial surface of the electrode assembly. Here, the second partial surface pressing process may be performed not only after the second entire surface pressing process is performed, but also before the second entire surface pressing process is performed.

Hereinafter, referring to fig. 7, the size of the non-bonding region of the stack according to whether the present invention is applied will be described. Here, the stack may be a bi-cell, and fig. 7 (a) illustrates a front image of the bi-cell fabricated according to the related art (hereinafter, referred to as "comparative example") and fig. 7 (b) illustrates a front image of the bi-cell fabricated according to the present invention (hereinafter, referred to as "embodiment of the present invention").

First, referring to the front image of the bicell (bi-cell) formed by the comparative example in fig. 7 (a), it can be seen that a non-bonding region having a black electrode and separator is formed on the upper portion of the bicell (bi-cell), i.e., the edge portion B corresponding to the electrode tab. Further, in the case of an electrode assembly including the unit cells as described above, it is expected that a non-bonding region between the unit cells and the separator sheet is generated, and thus, lithium is precipitated on the negative electrode, thereby increasing the resistance of the electrode. Thus, there may be caused a problem in that the performance of the secondary battery is deteriorated.

On the other hand, referring to the front image of the bicell (bi-cell) formed according to the embodiment of the present invention in fig. 7 (B), it can be seen that the non-bonding region is hardly formed on the upper portion of the bicell (bi-cell), i.e., the edge portion B corresponding to the electrode tab. Accordingly, it is expected that the electrode unit formed according to the embodiment of the present invention will hardly form not only the non-bonding region of the electrode and the separator inside the electrode unit, but also the non-bonding region between the unit cell and the separator sheet on the electrode assembly, and thus, there may be an advantage in that the performance of the secondary battery is improved by minimizing lithium precipitation on the anode due to interfacial resistance.

Although embodiments of the present invention have been described with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention as defined in the following claims.

[ description of the reference numerals ]

10: stacked body

11: the whole surface

12: local surface

12a: a first partial surface

12b: a second partial surface

13: the rest of the surfaces

14: electrode tab

101: electrode

1011: electrode current collector

1012: electrode active material layer

1013: edge portion

102: diaphragm

20: electrode plate

100: pressing part

110: main pressing part

120: auxiliary pressing part

121: drum part

121a: main body part

121b: elastic part

122: rotary shaft

123: pressure sensor

124: injection part

200: heating part

300: pressure detecting section

310: sensor unit

320: and a display unit.

Claims (19)

1. An apparatus for manufacturing a secondary battery, the apparatus comprising a pressing part configured to press a stack body alternately provided with electrodes and separators,

wherein the pressing portion includes:

a main pressing portion configured to press an entire surface of the stack; and

a sub-pressing portion including a drum portion configured to press a partial surface of the stack where an edge portion of an electrode active material layer provided on each of the electrodes is located, of an entire surface of the stack,

Wherein the drum portion includes:

a main body portion having a rotation axis; and

an elastic portion provided on an outer peripheral surface of the main body portion and configured to press the partial surface of the stacked body.

2. The apparatus according to claim 1, wherein the edge portion of the electrode active material layer has a curved surface whose height gradually decreases toward an end thereof, and

the drum portion is configured to press the edge portion and the separator such that the edge portion and the separator of the electrode active material layer corresponding to each other are bonded to each other.

3. The apparatus of claim 2, wherein the resilient portion is configured to be elastically deformable.

4. The apparatus of claim 3, wherein the elastic portion has an inner space, and

air (air) or fluid is filled into the inner space to maintain a preset pressure.

5. The apparatus according to claim 3, wherein the elastic portion is made of a deformable synthetic resin, and

the synthetic resin is set as silicone rubber.

6. The apparatus of claim 1, wherein the shape of the secondary pressing portion is deformed only when the partial surface is pressed.

7. The apparatus according to claim 1, further comprising a pressure detecting portion configured to detect a pressure applied to the partial surface of the stacked body by the sub-pressing portion.

8. The apparatus according to claim 7, wherein the pressure detecting section includes:

a sensor portion that senses pressure; and

and a display unit for displaying the pressure sensed by the sensor unit.

9. The apparatus according to claim 8, wherein the sensor portion is provided to face the sub-pressing portion with the partial surface of the stacked body interposed therebetween.

10. The apparatus of claim 1, wherein the stack comprises an electrode tab connected to the electrode, and

the sub-pressing part presses the partial surface of the stack where the edge portion of the electrode active material layer provided on the electrode connected to the electrode tab is located.

11. The apparatus of claim 1, wherein the secondary pressing portion is disposed on at least one of a front side and a rear side of the primary pressing portion.

12. The apparatus according to claim 11, further comprising a heating portion provided behind the pressing portion to apply heat to the stacked body in which the electrode and the separator are stacked,

Wherein the secondary pressing portion is disposed between the heating portion and the primary pressing portion.

13. The apparatus according to claim 1, wherein the edge portion is located at each of both end portions of the electrode active material layer provided on each of the electrodes, and

the drum portions are provided in pairs, and a pair of drum portions presses the partial surfaces of the stack body where the edge portions at both end portions of the electrode active material layer are located, respectively.

14. The device according to claim 1, wherein the edge portions are respectively located at both end portions of the electrode active material layer provided on the electrode, and

the drum portion is configured to press a surface including the partial surface of the stacked body where the edge portion of each of both end portions of the electrode active material layer is located.

15. The apparatus of claim 4, wherein the sub-pressing part further comprises a pressure sensor configured to measure a pressure of air (air) or fluid filled into the inner space of the elastic part.

16. The apparatus of claim 4, wherein the sub-pressing part further comprises an injection part configured to inject air (air) or fluid into an inner space of the elastic part through the body part.

17. The apparatus according to claim 1, wherein the sub-pressing portions are provided in pairs, a pair of sub-pressing portions being provided to correspond to upper and lower portions of the partial surface of the stack to simultaneously press the upper and lower portions of the partial surface of the stack.

18. A method of manufacturing a secondary battery, the method comprising:

an electrode unit manufacturing step of manufacturing an electrode unit in which electrodes and separators are alternately stacked;

an electrode assembly manufacturing step of providing a separator sheet between the plurality of electrode units manufactured in the electrode unit manufacturing step to manufacture an electrode assembly; and

a pressing process of pressing the electrode assembly,

wherein the electrode unit manufacturing process includes:

a stacking process of alternately disposing the separator and the electrode to form a stack;

a bonding process of bonding each separator and each electrode provided in the stack to each other;

wherein the bonding process comprises:

an entire surface pressing step of pressing an entire surface of the stacked body; and

a first partial surface pressing process of pressing a partial surface of the stack where an edge portion of an electrode active material layer provided on the electrode is located, out of the entire surface of the stack.

19. The method of claim 18, wherein the electrode assembly pressing process comprises:

a second entire surface pressing process of pressing an entire surface of the electrode assembly; and

and a second partial surface pressing process of pressing a partial surface of the electrode assembly where an edge portion of an electrode active material layer provided on the electrode is located, among the entire surface of the electrode assembly.