KR102703303B1 - Method for manufacturing secondary battery and secondary battery using the same - Google Patents

Abstract

The present invention relates to a method for manufacturing a secondary battery including a non-conductive portion that can easily connect a current collecting plate while ensuring insulation, and a secondary battery using the same.
For example, a method for manufacturing a secondary battery is disclosed, including the steps of forming an active material layer by coating an active material on a portion of a current collecting plate; forming a support member on a portion of a non-coated portion of the current collecting plate where the active material is not coated; heating the non-coated portion on which the support member is formed; and pressurizing the non-coated portion and then connecting a current collecting plate to the non-coated portion.

Description

Method for manufacturing secondary battery and secondary battery using the same {Method for manufacturing secondary battery and secondary battery using the same}

The present invention relates to a method for manufacturing a secondary battery and a secondary battery using the same.

Secondary batteries, unlike primary batteries that cannot be recharged, are batteries that can be charged and discharged. Low-capacity batteries in which a single battery cell is packaged in a pack form are used in small portable electronic devices such as mobile phones and camcorders, and large-capacity batteries in which dozens of battery packs are connected are widely used as power sources for driving motors in hybrid cars.

These secondary batteries are manufactured in various shapes, and representative shapes include cylindrical, square, and pouch shapes. They are composed of an electrode assembly formed by interposing a separator, which is an insulator, between positive and negative plates, and an electrolyte installed inside a case, and a cap plate installed in the case.

The above-described information disclosed in the background technology of this invention is only intended to improve understanding of the background of the present invention and therefore may include information that does not constitute prior art.

The present invention provides a method for manufacturing a secondary battery capable of easily connecting a current collecting plate while ensuring insulation, and a secondary battery using the same.

The method for manufacturing a secondary battery according to the present invention may include a step of forming an active material layer by coating an active material on a portion of a current collecting plate; a step of forming a support member on a portion of a non-coated portion of the current collecting plate where the active material is not coated; a step of heating the non-coated portion where the support member is formed; and a step of pressurizing the non-coated portion and then connecting a current collecting plate to the non-coated portion.

The above-mentioned support member can be formed in a portion adjacent to the above-mentioned active material layer.

In the step of forming the above-mentioned support member, an insulating tape can be attached to the above-mentioned plain portion.

In the step of forming the above-mentioned support member, an insulating material can be coated on the above-mentioned plain portion.

In the step of heating the above-mentioned plain portion, the support member may be hardened and the above-mentioned plain portion may have ductility.

In the step of connecting the collector plate to the above-mentioned plain portion, the plain portion in a part where the support member is not formed can be pressed.

In the step of heating the above-mentioned non-conductive part, the non-conductive part can be heated by induction heating, a laser, or an infrared lamp.

In addition, a secondary battery according to the present invention includes an electrode plate having a current collector plate, an active material layer formed on the current collector plate, and a non-conductive portion of the current collector plate where the active material layer is not formed; and a support member formed on a portion of the non-conductive portion adjacent to the active material layer; wherein the non-conductive portion can be heated after the support member is formed.

The invention further includes a collector plate connected to the other side of the non-heated portion, wherein the collector plate can be welded to the heated non-heated portion.

The above support member may be made of insulating tape or coated with an insulating material.

A method for manufacturing a secondary battery according to one embodiment of the present invention comprises forming an insulating member in a portion of a non-conductive portion and then heating the non-conductive portion, whereby the non-conductive portion can secure insulation and strength by the insulating member and at the same time secure ductility by heat treatment, thereby making it possible to easily weld a current collecting plate.

FIG. 1 is a flowchart illustrating a method for manufacturing a secondary battery according to one embodiment of the present invention.
FIGS. 2A to 2I are drawings for explaining a method for manufacturing a secondary battery according to one embodiment of the present invention.
Figure 3 is a photograph comparing the change in characteristics before and after heat treatment of the bare part.
Figure 4 is a graph comparing the change in tensile strength before and after heat treatment of the bare part.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

The embodiments of the present invention are provided so that those skilled in the art will more fully understand the present invention, and the following embodiments may be modified in various other forms, and the scope of the present invention is not limited to the following embodiments. Rather, these embodiments are provided so that the present disclosure will be more faithful and complete, and so that those skilled in the art will fully convey the spirit of the present invention.

In addition, in the drawings below, the thickness and size of each layer are exaggerated for convenience and clarity of explanation, and the same symbols in the drawings represent the same elements. As used herein, the term "and/or" includes any one of the listed items and any combination of one or more.

The terminology used herein is used to describe particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" include plural forms unless the context clearly dictates otherwise. Also, when used herein, the words "comprise" and/or "comprising" specify the presence of stated features, numbers, steps, operations, elements, elements and/or groups thereof, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, elements, elements and/or groups thereof.

FIG. 1 is a flowchart illustrating a method for manufacturing a secondary battery according to one embodiment of the present invention. FIGS. 2a to 2i are drawings for explaining a method for manufacturing a secondary battery according to one embodiment of the present invention.

Referring to FIG. 1, a method for manufacturing a secondary battery according to one embodiment of the present invention includes an active material layer forming step (S1), a support member forming step (S2), a non-conductive portion heating step (S3), an electrode assembly forming step (S4), a current collecting plate connecting step (S5), and a cap assembly bonding step (S6).

The active material layer forming step (S1) is a step of coating an active material on at least one surface of a current collector plate (111). As illustrated in FIG. 2a, in the active material layer forming step (S1), an active material is coated on both surfaces of a current collector plate (111) that is unwound from an unwinding roller (10) to form an active material layer (112). The active material is discharged through a slot die (20) and is uniformly applied to both surfaces of the current collector plate (111). For example, the current collector plate (111) may be formed of a metal foil or mesh such as aluminum or an aluminum alloy, and the active material may include a transition metal oxide. In addition, as illustrated in FIGS. 2b and 2c, in the active material layer forming step (S1), an active material layer (112) is continuously formed on the current collector plate (111), and a non-coated portion (113) on which the active material is not applied is formed on one end of the current collector plate (111). Therefore, the non-conductive portion (113) is formed parallel to the longitudinal direction of the collector plate (111).

The support member forming step (S2) is a step of forming a support member (114) in a part of the non-woven portion (113). As illustrated in FIG. 2d, in the support member forming step (S2), the support member (114) is formed in a part of the non-woven portion (113) adjacent to the active material layer (112). The part of the non-woven portion (113) where the support member (114) is formed is referred to as a first region (A1), and the part where the support member (114) is not formed is defined as a second region (A2). In the support member forming step (S2), the support member (114) can be formed by attaching an insulating tape to the first region (A1) of the non-woven portion (113). In addition, in the support member forming step (S2), the support member (114) can be formed by coating an insulating material on the first region (A1) of the non-woven portion (113). In addition, as illustrated in FIG. 2e, a support member (114) may be formed on both sides of the current collector plate (111). The support member (114) may be made of an insulating material, for example, polyimide (PI), polypropylene (PP), polyethylene terephthalate (PET), or an equivalent thereof. The support member (114) is formed in a portion adjacent to the active material layer (112) to prevent electrical short-circuiting with electrode plates having different polarities when forming an electrode assembly. In addition, the support member (114) serves to reinforce the strength of the non-conductive portion (113). That is, when the non-conductive portion (113) is pressed to connect the current collector plate to the non-conductive portion (113), the first region (A1) of the portion adjacent to the active material layer (112) is not significantly bent or deformed by the support member (114). Therefore, a short-circuiting due to deformation of the non-conductive portion (113) can be prevented.

The non-heating step (S3) is a step of applying heat to the non-heating part (113). As illustrated in FIG. 2f, in the non-heating step (S3), heat is applied to the non-heating part (113) to change the properties of the current collector (111). Specifically, when heat is applied to the non-heating part (113), the crystal grains of the current collector (111) change, thereby becoming ductile. In addition, in the non-heating step (S3), heat is also applied to the support member (114) formed on the non-heating part (113), and accordingly, the support member (114) is hardened, thereby further increasing the strength. In the non-heating step (S3), the non-heating part (113) can be heated using induction heating (IHA), a laser, an infrared lamp (IR lamp), or the like.

In this way, when the non-conductive portion (113) is heated, the first region (A1) becomes stronger because the support member (114) is hardened, and the second region (A2) becomes ductile. Therefore, when the non-conductive portion (113) is pressed to connect the current collecting plate to the non-conductive portion (113), the first region (A1) does not bend or deform significantly, thereby preventing a short circuit, and the second region (A2) can be easily deformed and flattened, thereby making it easy to connect the current collecting plate.

In addition, the electrode plate (110) manufactured by the above method is defined as the first electrode plate (positive electrode plate). In addition, the second electrode plate (negative electrode plate) having the opposite polarity to the first electrode plate is also manufactured by the same method as above, so a description thereof will be omitted.

The electrode assembly forming step (S4) is a step of forming an electrode assembly (140) by winding the first electrode plate (110), the separator (130), and the second electrode plate (120). As illustrated in FIG. 2g, in the electrode assembly forming step (S4), a separator (130) is interposed between the first electrode plate (110) and the second electrode plate (120), and then the separator is wound to form an electrode assembly (140). The second electrode plate (120) is formed by the same manufacturing method as the first electrode plate (110), and includes a current collector plate (121), an active material layer (122), a non-conductive portion (123), and a support member (124). The current collector plate (121) of the second electrode plate (120) may be formed of a metal foil or mesh such as copper or nickel, and the active material layer (122) may include graphite or carbon, etc. In addition, the support member (124) of the second electrode plate (120) may be formed by attaching an insulating tape to the non-conductive portion (123) or coating an insulating material.

In the electrode assembly forming step (S4), the uncoated portion (113) of the first electrode plate (110) is positioned and wound so that the uncoated portion (123) of the second electrode plate (120) faces downward. In addition, the size of the separator (130) is formed to correspond to the sizes of the active material layers (112, 122) of the first electrode plate (110) and the second electrode plate (120). Accordingly, the uncoated portion (113) of the first electrode plate (110) protrudes upwardly from the electrode assembly (140), and the uncoated portion (123) of the second electrode plate (120) protrudes downwardly from the electrode assembly (140).

The current collector plate connection step (S5) is a step of electrically connecting the current collector plates (150, 160) to the electrode assembly (140). As illustrated in FIG. 2h, in the current collector plate connection step (S5), the first current collector plate (150) is welded to the non-coated portion (113) protruding upwardly of the electrode assembly (140), and the second current collector plate (160) is welded to the non-coated portion (123) protruding downwardly. Here, the current collector plates (150, 160) can be connected to the respective non-coated portions (113, 123) by laser welding, resistance welding, ultrasonic welding, or the like. In addition, before connecting the current collecting plates (150, 160), a process of pressing and flattening the non-conductive portion (113, 123) is performed, so that the current collecting plates (150, 160) can be easily welded to the non-conductive portion (113, 123). As illustrated in FIG. 2h, the welded portion (150) of the first current collecting plate (150) is formed in an approximately ‘+’ shape, so that the non-conductive portion (113) is also pressed in a ‘+’ shape corresponding to the welded portion (151). Of course, the entire non-conductive portion (113) may be pressed depending on the shape of the first current collecting plate (150). When the non-conductive portion (113) is pressed, the second region (A2) that is ductile due to heat treatment is pressed. Then, the welded portion (151) of the first current collecting plate (150) and the non-conductive portion (113) are electrically connected by welding. Similarly, after pressurizing the uncoated portion (123) of the second electrode plate (120), the welding portion (161) of the second current collecting plate (160) is welded to the uncoated portion (123) to electrically connect them.

The first current collecting plate (150) includes a welding portion (151) welded to the non-conductive portion (113) of the first electrode plate (110), a hole (152) through which an electrolyte is injected, and a connecting portion (153) electrically connected to a cap assembly (180). Here, the connecting portion (153) may be bent upwards to be electrically connected to the cap assembly (180). In addition, the second current collecting plate (160) includes a welding portion (161) welded to the non-conductive portion (123) of the second electrode plate (120), a hole (162) through which an electrolyte moves, and a connecting portion (163) electrically connected to a case (170).

The cap assembly joining step (S6) is a step of inserting the electrode assembly (140) into the case (170) and joining the cap assembly (180) to the top of the case (170). As illustrated in FIG. 2i, in the cap assembly joining step (S6), the electrode assembly (140) is inserted into the case (170), the connecting portion (163) of the second current collecting plate (160) and the bottom surface of the case (170) are electrically connected by welding, and the connecting portion (153) of the first current collecting plate (150) and the sub-plate (185) of the cap assembly (180) are electrically connected by welding. Then, an electrolyte is injected into the case (170), and the cap assembly (180) is joined to the top of the case (170), thereby completing the secondary battery (100) according to the present invention. Here, the cap assembly (180) includes a cap up (181), a safety vent (182) coupled to the lower portion of the cap up (181), a cap down (183) coupled to the lower portion of the safety vent (182), an insulator (184) positioned between the safety vent (182) and the cap down (183), a subplate (185) coupled to the lower portion of the cap down (183) and electrically connected to the safety vent (182), and a gasket (186) interposed between the outer periphery of the safety vent (182) and the case (170).

As described above, a method for manufacturing a secondary battery according to one embodiment of the present invention forms an insulating member in a portion of a non-conductive portion and then heats the non-conductive portion, so that the non-conductive portion can secure insulation and strength by the insulating member and at the same time secure ductility by heat treatment, thereby making it easy to weld a current collecting plate.

Next, we will examine the change in characteristics according to heat treatment of the bare part.

Figure 3 is a photograph comparing the change in characteristics before and after heat treatment of the bare part.

First, in Fig. 3, the heat treatment of the plain region was performed using induction heating (IHA). As shown in Fig. 3, when the plain region that has not been subjected to induction heating (IHA) is pressed, the deformation of the plain region is irregular and deformation occurs in a portion adjacent to the active material layer, which poses a risk of short circuit. On the other hand, it can be confirmed that the plain region that has been subjected to induction heating (IHA) becomes ductile, and the portion where force is applied when pressed, that is, the portion that is relatively far from the active material layer, is pressed well. Accordingly, the electrode plate having the induction-heated plain region can prevent a short circuit with an adjacent electrode plate.

Figure 4 is a graph comparing the change in tensile strength before and after heat treatment of the bare part.

Referring to Fig. 4, the tensile strength of the plain region that has not been inductively heated (IHA) is about 220 to 260 N/m㎟, and the tensile strength of the plain region that has been inductively heated (IHA) is about 60 to 120 N/m㎟, confirming that the tensile strength of the plain region that has been inductively heated (IHA) is relatively weaker. In other words, it can be seen that when the plain region is inductively heated (IHA), ductility is created, and the plain region is easily pressed when pressurized.

The above description is only one embodiment for implementing the method for manufacturing a secondary battery according to the present invention and the secondary battery using the same, and the present invention is not limited to the above-described embodiment, and as claimed in the following claims, it will be understood that the technical spirit of the present invention encompasses a range in which various modifications can be implemented without departing from the gist of the present invention.

100: Secondary battery 110: First electrode plate
111: current collector plate 112: active material layer
113: No support 114: No support
120: Second electrode plate 121: Collector plate
122: Active material layer 123: Non-active layer
124: Absence of support 130: Separator
140: Electrode assembly 150: First collector plate
160: Second collector plate 170: Case
180: Cap assembly

Claims (10)

A step of forming an active material layer by coating an active material on a part of a collector plate;
A step of forming a support member on a part of a non-coated portion of the above current collector plate;
A step of heating the non-conductive part after the support member is formed; and
A step of pressurizing the above-mentioned non-conductive part and then connecting a current collecting plate to the above-mentioned non-conductive part;
The above-mentioned portion includes a first region where the support member is formed and a second region where the support member is not formed.
In the step of heating the above-mentioned area, the first area and the second area are heated,
In the step of connecting the current collecting plate to the above-mentioned non-conductive region, the current collecting plate is connected to the second region,
A method for manufacturing a secondary battery, characterized in that in the step of heating the above-mentioned blank region, the first region is hardened and the second region is ductile. In the first paragraph,
A method for manufacturing a secondary battery, characterized in that the support member is formed in a portion adjacent to the active material layer. In the first paragraph,
A method for manufacturing a secondary battery, characterized in that in the step of forming the above-mentioned support member, an insulating tape is attached to the above-mentioned plain portion. In the first paragraph,
A method for manufacturing a secondary battery, characterized in that in the step of forming the above-mentioned support member, an insulating material is coated on the above-mentioned non-conductive portion. delete In the first paragraph,
In the step of connecting the collector plate to the above-mentioned non-conductive part,
A method for manufacturing a secondary battery, characterized in that the second region of the above-mentioned non-conductive portion is pressed. In paragraph 1,
A method for manufacturing a secondary battery, characterized in that in the step of heating the non-conductive portion, the non-conductive portion is heated by induction heating, a laser, or an infrared lamp. An electrode plate having a current collector plate, an active material layer formed on the current collector plate, and a non-conductive portion of the current collector plate where the active material layer is not formed; and
Including a support member formed in a portion adjacent to the active material layer in the above-mentioned non-conductive portion;
Further comprising a collector plate connected to the other side of the above-mentioned non-conductive portion,
The above-mentioned non-conductive region includes a first region where the support member is formed adjacent to the active material layer, and a second region where the support member is not formed.
When the above-mentioned non-metallic region is heated, the first region is hardened and the second region is ductile.
A secondary battery, characterized in that the above-mentioned current collecting plate is welded to the above-mentioned second region. delete In Article 8,
A secondary battery characterized in that the above-mentioned supporting member is made of an insulating tape or coated with an insulating material.

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