KR100824867B1 - Can type and pouch type secondary battery having ptc device on protected circuit board - Google Patents

Abstract

The present invention relates to a can-type and pouch-type secondary battery, comprising: a bare cell having an electrode assembly, a can housing the electrode assembly, and a cap assembly coupled to an open upper portion of the can; A protection circuit board on which a protection circuit is formed; And a first conductive portion directly bonded to the protective circuit board, a second conductive portion bonded to one component of the cap assembly electrically connected to one electrode of the electrode assembly, the first conductive portion and the second conductive portion. And a can-type secondary battery including a PTC element having a PTC main body positioned between the conductive parts, an electrode assembly, and a pouch case sealed to receive the electrode assembly and to expose a part of the electrode tab drawn from the electrode assembly. One bare cell; A protection circuit board on which a protection circuit is formed; And a PTC element including a first conductive portion directly bonded to the protective circuit board, a second conductive portion bonded to the electrode tab, and a PTC body portion positioned between the first conductive portion and the second conductive portion. It provides a pouch-type secondary battery comprising a.

Description

CAN AND POUCH TYPE SECONDARY BATTERY HAVING PTC DEVICE ON PROTECTED CIRCUIT BOARD}

1 is a partial perspective view of a can type secondary battery having a conventional PTC device.

Figure 2 is an exploded perspective view of a can type secondary battery according to an embodiment of the present invention.

3 is a cross-sectional view of a state in which a PTC device according to an embodiment of the present invention shown in FIG. 2 is attached to a protective circuit board.

4A is a cross-sectional view of a PTC device according to another embodiment of the present invention.

4B is a bottom view of the first conductive portion in FIG. 4A.

5A is a cross-sectional view of a PTC device according to still another embodiment of the present invention.

FIG. 5B is a bottom view of the first conductive portion in FIG. 5A; FIG.

6A is a cross-sectional view of a PTC device according to still another embodiment of the present invention.

FIG. 6B is a bottom view of the first conductive portion in FIG. 6A; FIG.

7A is a cross-sectional view of a PTC device according to another embodiment of the present invention.

FIG. 7B is a bottom view of the first conductive portion in FIG. 7A; FIG.

8 is a cross-sectional view of a PTC device according to another embodiment of the present invention.

<Description of Symbols for Main Parts of Drawings>

10: secondary battery 11: can

12: electrode assembly 100: cap assembly

110: cap plate 130: electrode terminal

170 ', 170a, 170b, 170c, 170d, 170e: PTC element

171a, 171b, 171c, 171d: first component

172a, 172b, 172c, 172d: second component

172 ', 173a, 173b, 173c, 173d, 173e: first conductive portion

174 ', 176a, 176b, 176c, 176d, 176e: PTC main body

176 ', 178a, 178b, 178c, 178d, 178e: second conductive portion

270,270a, 270b, 270c, 270d, 270e: joining member

300: protection circuit board

The present invention relates to a secondary battery, and more particularly to a can type and pouch type secondary battery.

In general, a secondary battery refers to a battery that can be charged and discharged, unlike a primary battery that cannot be charged, and is widely used in the field of advanced electronic devices such as a cellular phone, a notebook computer, a camcorder, and the like. In particular, lithium secondary batteries have an operating voltage of 3.6V, which is three times higher than nickel-cadmium batteries or nickel-hydrogen batteries, which are widely used as electronic equipment power sources, and are rapidly increasing in terms of high energy density per unit weight.

Such lithium secondary batteries mainly use lithium-based oxides as positive electrode active materials and carbon materials as negative electrode active materials. Moreover, although lithium secondary batteries are manufactured in various shapes, typical shapes include cylindrical shape, square shape, and pouch type.

Among them, the rectangular secondary battery includes a bare cell, a protective circuit board on which a protection circuit is formed, and a PTC device, which is a safety device positioned between the protective circuit board and the bare cell.

The bare cell includes an electrode assembly, a can containing the electrode assembly, and a cap assembly coupled to an open top of the can.

The electrode assembly is wound in the order of the positive electrode, the separator, and the negative electrode, and the positive and negative electrode tabs are drawn out from the positive and negative electrodes, respectively.

The can is a metal container having a substantially rectangular parallelepiped shape in a rectangular secondary battery, and is formed by a processing method such as deep drawing.

The cap assembly includes a cap plate coupled to an upper portion of the can, an electrode terminal installed through a terminal hole formed in the cap plate while a gasket is disposed on an outer surface thereof, an insulating plate installed on a lower surface of the cap plate, and the insulation. It is installed on the lower surface of the plate includes a terminal plate that is energized with the electrode terminal.

The positive electrode tab is electrically connected to the cap plate, and the negative electrode tab is electrically connected to the electrode terminal through the terminal plate. However, the positive and negative electrode tabs may be designed with different polarities.

In addition, a safety device such as a PTC element (Positive Temperature Coefficient device) is provided on the path of the current from one electrode of the bare cell to the protection circuit formed on the protection circuit board. This PTC device prevents the battery from rupturing by blocking the flow of current when the battery voltage rises rapidly due to the high temperature rise of the battery or excessive charge and discharge.

1 is a partial perspective view of a secondary battery having a conventional PTC device.

Referring to the drawings, the conventional PTC element 170 of the secondary battery is a flat plate-shaped first conductive portion 172, the plate-shaped second conductive portion 176, and the flat shape between the two conductive portions The PTC main body 174 is formed. The lower surface of the first conductive portion 172 is contact-fixed on the insulating member 185 for insulation between the cap plate 110 and the PTC device 170, the upper surface is welded and fixed to the lead plate 220. The lead plate 220 serves as an electrical connection path between the PTC device 170 and the protection circuit board (not shown). The second conductive portion 176 is directly or indirectly connected to the electrode terminal 130.

Here, the PTC body portion 174 is prepared by dispersing the conductive particles in the crystalline polymer, and below the set temperature, the PTC body portion 174 connects the flow of current between the first conductive portion 172 and the second conductive portion 176. Play a role. However, when over current or over voltage flows or power is consumed while the battery is in use, and heat is generated accordingly, the temperature rises above the set temperature. Accordingly, the conductive particles drop due to the expansion of the crystalline polymer, and the resistance rapidly increases to block the flow of current. Or a low amount of current flows, thereby acting as a safety device to prevent battery rupture. Then, when the temperature is lowered below the set temperature again, the crystalline polymer contracts to restore the connection between the conductive particles to operate the current to resume.

However, the conventional structure in which the PTC device 170 is connected to the protective circuit board and the bare cell has the following problems.

In order for the PTC main body to perform the above-described role smoothly among the PTC elements, the path of the current from one electrode of the bare cell to the protection circuit formed on the protection circuit board needs to be short and the electrical resistance of the conductive parts must be low. However, in the conventional structure shown in FIG. 1, various components other than the PTC element 170 are positioned between the protective circuit board and the bare cell. Accordingly, the path of the current is long, so that the PTC element may not operate at the designed original operating temperature and may have a large error range, thereby making it difficult to control.

In addition, in the conventional structure, there are various components besides the PTC element 170 as a passage for moving the current generated from one electrode of the bare cell to the protection circuit board, which complicates the manufacturing process of the battery, thereby increasing the cost. There is a problem.

This problem occurs not only in the can type secondary battery, but also in the pouch type secondary battery.

An object of the present invention is to enable a PTC device located between a bare cell and a protective circuit board to operate smoothly at a designed temperature.

Another object of the present invention is to reduce the time and cost of the battery manufacturing process by reducing unnecessary parts.

Another object of the present invention is to maximize the space efficiency between the bare cell and the protective circuit board to enable a slim pack design.

According to an aspect of the present invention, a can type secondary battery includes: a bare cell having an electrode assembly, a can housing the electrode assembly, and a cap assembly coupled to an open upper portion of the can; A protection circuit board on which a protection circuit is formed; And a first conductive portion directly bonded to the protective circuit board, a second conductive portion bonded to one component of the cap assembly electrically connected to one electrode of the electrode assembly, the first conductive portion and the second conductive portion. It is characterized by comprising a PTC element having a PTC body portion located between the conductive portions.

In addition, a pouch-type secondary battery according to an aspect of the present invention comprises a bare cell having an electrode assembly and a pouch case for receiving the electrode assembly and sealing a portion of the electrode tab drawn out from the electrode assembly; A protection circuit board on which a protection circuit is formed; And a PTC element including a first conductive portion directly bonded to the protective circuit board, a second conductive portion bonded to the electrode tab, and a PTC body portion positioned between the first conductive portion and the second conductive portion. Characterized in that the made up.

According to another aspect of the present invention, a can type secondary battery includes: a bare cell having an electrode assembly, a can housing the electrode assembly, and a cap assembly coupled to an open upper portion of the can; A protection circuit board on which a protection circuit is formed; And a first conductive portion directly bonded to the protective circuit board by a bonding member, a second conductive portion electrically connected to one electrode of the bare cell, and positioned between the first conductive portion and the second conductive portion. And a PTC element having a PTC body portion, wherein the first conductive portion of the PTC element includes a first component including a contact portion in contact with the PTC body portion, and a large area portion having a larger cross-sectional area than the contact portion. And a second component, wherein the joining member is formed to cover at least a portion of the second component.

In addition, a can-type secondary battery according to another aspect of the present invention, a bare cell having an electrode assembly, a can housing the electrode assembly, and a cap assembly coupled to an open upper portion of the can; A protection circuit board on which a protection circuit is formed; And a first conductive portion directly bonded to the protective circuit board by a bonding member, a second conductive portion electrically connected to one electrode of the bare cell, and positioned between the first conductive portion and the second conductive portion. And a PTC element having a PTC main body, wherein an area of the first conductive portion of the PTC element is larger than that of the PTC main body, and the joining member is formed to cover a portion of the first conductive portion.

On the other hand, the pouch-type secondary battery according to another aspect of the present invention for achieving the above object, the pouch case sealed to receive the electrode assembly, the electrode assembly and a portion of the electrode tab drawn from the electrode assembly is exposed. Bare cell provided; A protection circuit board on which a protection circuit is formed; And a first conductive portion directly bonded to the protective circuit board by a bonding member, a second conductive portion bonded to the electrode tab, and a PTC body portion positioned between the first conductive portion and the second conductive portion. And a PTC element, wherein the first conductive portion of the PTC element includes a first component including a contact portion in contact with the PTC body portion, and a second area including a large area having a larger cross-sectional area than the contact portion. It is made to include a component, characterized in that the bonding member is formed to cover at least part of the second component.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of a can type secondary battery according to an aspect of the present invention.

2 is an exploded perspective view of a can type secondary battery according to an exemplary embodiment of the present invention.

Referring to the drawings, the secondary battery 10 includes a bare cell, a protective circuit board 300 on which a protection circuit is formed, and a PTC device 170 'which is a safety device positioned between the protective circuit board 300 and the bare cell. It includes.

The bare cell includes an electrode assembly 12, a can 11 accommodating the electrode assembly 12, and a cap assembly 100 coupled to an open upper portion of the can 11.

The electrode assembly 12 typically forms a wide plate shape of the positive electrode 13 and the negative electrode 15 to increase the capacitance, and then interposes a separator 14 between the positive electrode 13 and the negative electrode 15 to insulate them from each other. It is then laminated, rolled up into a vortex to form a so-called 'Jelly Roll'. The negative electrode 15 and the positive electrode 13 may be formed by coating carbon as the negative electrode active material and lithium cobalt as the positive electrode active material, respectively, on a current collector made of copper and aluminum foil. The separator 14 consists of polyethylene, polypropylene, or a copolymer of polyethylene and polypropylene. Separator 14 is formed to be wider than the positive electrode 13 and the negative electrode 15 is advantageous to prevent short circuit between the electrode plates. In the electrode assembly 12, positive and negative electrode tabs 16 and 17 connected to each electrode are drawn out. Insulating tape 18 is wound around the positive and negative electrode tabs 16 and 17 to prevent a short circuit between the electrode plates 13 and 15 at the boundary portion drawn out of the electrode assembly 12.

The can 11 is a metal container having a substantially rectangular parallelepiped shape in a rectangular secondary battery as shown, and formed by a processing method such as deep drawing. Thus, it is also possible for the can itself to serve as a terminal. As the material for forming the can, aluminum or aluminum alloy, which is a lightweight conductive metal, is preferable. The can 11 becomes a container of the electrode assembly 12 and the electrolyte solution, and the upper part opened to the electrode assembly 12 is sealed by the cap assembly 100.

The cap assembly 100 includes a cap plate 110, an electrode terminal 130, an insulating plate 140, and a terminal plate 150. The cap plate 110 has a terminal through hole 111 formed therein, and the electrode terminal 130 penetrates through the terminal through hole 111 with the gasket 120 positioned on the outer surface thereof to insulate the cap plate 110. Is installed. An insulating plate 140 is provided on the lower surface of the cap plate 110, and a terminal plate 150 is provided on the lower surface of the insulating plate 140. The lower end of the electrode terminal 130 is coupled to the terminal plate 150.

The negative electrode 15 of the electrode assembly 12 is electrically connected to the electrode terminal 130 through the negative electrode tab 17 and the terminal plate 150. In the case of the positive electrode 13 of the electrode assembly 12, the positive electrode tab 16 is welded to the cap plate 110 or the can 11. An insulating case 190 may be further installed below the terminal plate 150. On the other hand, the battery may be designed by changing the polarity.

An electrolyte injection hole 112 is formed at one side of the cap plate 110 to inject the electrolyte into the can 11. After the electrolyte is injected, a cap 160 is used or an electrolyte is injected by injecting a ball. Seal the ball 112. In addition, the other side of the cap plate 110 is provided with a holder 182 for increasing the resistance strength to the torsion or bending of the resin in the battery pack formed by hot-melting (hot-melting) method.

On the other hand, the protective circuit board 300 is formed by a protective circuit formed on a panel made of a resin, the external input and output terminals and the like is formed on the outer surface. The protective circuit board 300 has substantially the same size and shape as the opposite surface (cap plate surface) of the bare cell. A protective circuit (not shown) and a connection terminal (not shown) are provided on the rear surface of the protective circuit board 300 on which the external input / output terminal 310 is formed, that is, the inner surface. The protection circuit is a circuit for protecting the battery from overcharging or overdischarging during charging and discharging, and is electrically connected to the connecting terminal.

In the present invention, the shape of the connection terminal may be a flat plate shape instead of the conventional "a-shape" type, and the connection terminal may be omitted. In addition, the protection circuit and each external input / output terminal 310 are electrically connected by a conductive structure passing through the protection circuit board 300.

In addition, a safety device such as a PTC element (Positive Temperature Coefficient device) 170 ′ is provided on a path of a current from one electrode of the bare cell to the protection circuit formed on the protection circuit board 300. The PTC device 170 ′ prevents the battery from rupturing by blocking the flow of current when the voltage of the battery is rapidly increased due to the high temperature of the battery or excessive charge / discharge.

The structure in which the PTC device 170 ′ is connected to the protective circuit board and the bare cell is as follows.

3 is a cross-sectional view showing a PTC device directly bonded to a protective circuit board.

Referring to the drawings, the PTC device 170 ′ of the can type secondary battery according to the present invention includes a first conductive portion 172 ′ directly bonded to a protection circuit board, and an electrical connection with one electrode of the electrode assembly. A second conductive portion 176 'joined to a part of the cap assembly, and a PTC body portion 174' positioned between the first conductive portion 172 'and the second conductive portion 176'. It is done by

Conventionally, the first conductive portion of the PTC element is connected to the connection terminal of the protective circuit board through the lead plate (see FIG. 1). However, in the present invention, the first conductive portion 172 'of the PTC element 170' is a plate type. The upper surface is directly bonded to the protection circuit board 300 (upper and lower in Fig. 3 is shown upside down).

Therefore, the path from the first conductive portion 172 'to the protective circuit board 300 is shortened, thereby reducing the electrical resistance. In addition, the lead plate is not necessary, and since the use of a small flat plate of a small size rather than the a-shaped connection terminal of the existing protection circuit board, or in some cases the use of the connection terminal can be excluded, the number of parts is reduced.

The first conductive portion 172 'is soldered to the protective circuit board.

In addition, a Ni-based material may be used as the first conductive portion 172 ', and the thickness of the first conductive portion 172' is preferably 0.2 mm or more. If the thickness of the first conductive portion 172 'is thinner than 0.2 mm, when soldering using the solder cream 270, the solder cream 270 is heated and comes up the side of the first conductive portion 172'. This is because a part of the side surface of the PTC main body 174 'may be covered, and there is a risk that the PTC main body 174' may not operate normally.

In addition, the second conductive portion 176 ′ is plate-shaped and may be joined to a cap plate having a positive polarity or an electrode terminal having a negative polarity. In FIG. 2, the second conductive portion 176 ′ is joined to the top surface of the cap plate 110.

As the second conductive portion 176 ′, a Ni-based material may be used. It is preferable that the thickness of the 2nd electroconductive part 176 'is 0.25 mm or more. If the thickness of the second conductive portion 176 'is thinner than 0.25 mm, there is a risk that the PTC body portion 174' is deformed by the heat applied to the PTC body portion 174 'during welding.

The PTC body portion 174 'is prepared by dispersing the conductive particles in the crystalline polymer, and the conductive particles are agglomerated below the set temperature so that the current between the first conductive portion 172' and the second conductive portion 176 'is reduced. It acts as a bridge to connect the flow.

However, when over current or over voltage flows or power is consumed while the battery is in use, and heat is generated accordingly, the temperature rises above the set temperature. Accordingly, the conductive particles drop due to the expansion of the crystalline polymer, and the resistance rapidly increases to block the flow of current. Or a low amount of current flows, thereby acting as a safety device to prevent battery rupture. Then, when cooled below the set temperature again, the crystalline polymer shrinks to restore the connection between the conductive particles and operates to resume current flow.

Carbon particles or Ni powder may be used as the conductive particles. When Ni powder is used rather than carbon particles, the conductivity is better. As the crystalline polymer, synthetic resin such as polyolefin resin may be used. It is preferable that the thickness of the PTC main body 174 'is 0.4 mm or more. If the thickness of the PTC body portion 174 'is thinner than 0.4 mm, the distance between the first conductive portion 172' and the second conductive portion 176 'is too close to control the operating temperature of the PTC element 170'. Because it is difficult.

The PTC device 170 'may be cubic or cylindrical. Referring to Fig. 1, the shape of the conventional PTC element is required to have a portion which does not overlap with the PTC body portion when the PTC element is viewed from above for joining with the lead plate. In addition, the second conductive portion also needs to have a portion which does not overlap with the PTC body portion when viewed from above for bonding the electrode terminal or the component attached to the electrode terminal. As a result, the conventional PTC element is difficult to have a cubic or cylindrical.

In contrast, in the present invention, the upper surface of the first conductive portion 172 'may be directly bonded to the protective circuit board, and the lower surface of the second conductive portion 176' may be directly bonded to the cap plate or the electrode terminal. It can have a cylindrical shape, and can take a simpler shape. However, the content of the present invention is not limited to the above shape.

On the other hand, although the electrical connection between the electrode terminal having a negative polarity and the protective circuit board in this embodiment is not shown, it may be connected to a conductive member of various forms.

Hereinafter, a pouch type secondary battery according to another aspect of the present invention will be described. However, description of the same contents as those of the can type secondary battery described above will be omitted.

The pouch type secondary battery includes a bare cell, a protective circuit board on which a protection circuit is formed, and a PTC device which is a safety device positioned between the protective circuit board and the bare cell.

The bare cell includes an electrode assembly and a pouch case that houses the electrode assembly and is sealed to expose a portion of the electrode tab drawn from the electrode assembly. Since the description of the structure of the bare cell is the same as that of the conventional bare cell, a description thereof will be omitted.

In addition, the protection circuit board is a substrate formed with a protection circuit for protecting the battery from overcharge or over discharge during charging and discharging, the description of this structure is the same as the structure of the conventional protection circuit board will be omitted.

The PTC device is positioned between the first conductive portion directly bonded to the protective circuit board, the second conductive portion bonded to the electrode tab partially exposed in the sealed pouch, and between the first conductive portion and the second conductive portion. It comprises a PTC body to be made (see Fig. 3).

Therefore, the path from the electrode tab of the bare cell to the protective circuit board is shortened, thereby reducing the electrical resistance. In addition, unlike the conventional structure, since the lead plate is unnecessary, the number of parts is reduced.

The first conductive portion is soldered to the protective circuit board.

In addition, the PTC device may be a cubic or cylindrical.

A detailed description of the structure and shape of the PTC device of the pouch type secondary battery is the same as that of the PTC device of the can type secondary battery, and thus will be omitted.

4A is a cross-sectional view illustrating a state in which a PTC device is directly bonded to a protection circuit board according to another embodiment of the present invention, and FIG. 4B is a bottom view of the first conductive part in FIG. 4A and shows only the protection circuit board and the first conductive part. Shown. This also applies to the drawings of FIGS. 5A, 5B to 7A, 7B.

4A and 4B, the PTC device 170a is electrically connected to a first conductive portion 173a directly connected to the protection circuit board 300 by the bonding member 270a, and to one electrode of the bare cell. And a PTC body portion 176a positioned between the second conductive portion 178a and the first conductive portion 173a and the second conductive portion 178a. Here, the first conductive portion 173a of the PTC element includes a first component portion 171a including a contact portion in contact with the PTC body portion 176a, and a second area including a large area portion having a larger cross-sectional area than the contact portion. It comprises a component 172a, the bonding member 270a is formed to cover at least a portion of the second component (172a).

The first component 171a and the second component 172a of the first conductive portion 173a are integrally formed in a stepped manner, and the first component 171a and the second component 172a are firstly formed. The step is formed only at both the left and right sides of the configuration portion 171a.

Conventionally, the first conductive portion of the PTC element is connected to the connection terminal of the protective circuit board through a lead plate (see FIG. 1), but the first conductive portion 173a of the PTC element 170a has a lower surface thereof on the protective circuit board 300. (The upper surface of the first conductive portion is directly bonded to the protective circuit board with reference to FIG. 2).

Therefore, the path from the first conductive portion 173a to the protective circuit board 300 is shortened, thereby reducing the electrical resistance. In addition, since the lead plate is not necessary and a flat plate of a small size other than the a-shaped connection terminal of the existing protection circuit board may be used, or in some cases, the use of the connection terminal may be eliminated, thereby reducing the number of parts.

In addition, the joining member 270a is formed to cover not only the bottom surface of the first conductive portion 173a but also the second component portion 172a, thereby providing a connection force between the PTC element 170a and the protective circuit board 300. Strengthen. Here, the solder paste may be used as the bonding member 270a, but the contents of the present invention are not limited thereto. On the other hand, it is necessary to prevent the joining member 270a from coming into contact with the PTC body 176a. This is to avoid disturbing the operation of the PTC main body 176a which is sensitively expanded and contracted according to temperature.

A Ni-based material may be used as the first conductive portion 173a, and the thickness of the first conductive portion 173a is preferably 0.2 mm or more. If the thickness of the first conductive portion 173a is thinner than 0.2 mm, when soldering using the solder paste, the solder paste is heated while climbing up the side of the first conductive portion 173a and the side surface of the PTC main body 176a. This is because a part may be covered and there is a risk that the PTC main body 176a does not operate normally.

In addition, the second conductive portion 178a may have a plate shape and may be joined to a cap plate having a positive polarity or an electrode terminal having a negative polarity.

As the second conductive portion 178a, a Ni-based material may be used. It is preferable that the thickness of the 2nd electroconductive part 178a is 0.25 mm or more. If the thickness of the second conductive portion 178a is thinner than 0.25 mm, there is a risk that the PTC body portion 176a is deformed by the heat applied to the PTC body portion 176a during welding.

The PTC body 176a is prepared by dispersing conductive particles in a crystalline polymer, and the conductive particles are aggregated at or below a set temperature to connect a current flow between the first conductive portion 173a and the second conductive portion 178a. Role. However, when over current or over voltage flows or power is consumed while the battery is in use, and heat is generated accordingly, the temperature rises above the set temperature. Accordingly, the conductive particles drop due to the expansion of the crystalline polymer, and the resistance rapidly increases to block the flow of current. Or a low amount of current flows, thereby acting as a safety device to prevent battery rupture. Then, when cooled below the set temperature again, the crystalline polymer shrinks to restore the connection between the conductive particles and operates to resume current flow.

Carbon particles or Ni powder may be used as the conductive particles. When Ni powder is used rather than carbon particles, the conductivity is better. As the crystalline polymer, synthetic resin such as polyolefin resin may be used. It is preferable that the thickness of the said PTC main body part 176a is 0.4 mm or more. If the thickness of the PTC body portion 176a is thinner than 0.4 mm, the distance between the first conductive portion 173a and the second conductive portion 178a is too close, making it difficult to control the operating temperature of the PTC element 170a. Because.

5A and 5B illustrate another embodiment of the present invention, in which the PTC device 170b includes a first conductive portion 173b directly bonded to the protection circuit board 300 by a bonding member 270b, and a bare cell. And a second body portion 178b electrically connected to one electrode, and a PTC body portion 176b positioned between the first conductive portion 173b and the second conductive portion 178b. Here, the first conductive portion 173b of the PTC element includes a first component portion 171b including a contact portion in contact with the PTC body portion 176b, and a second area including a large area portion having a larger cross-sectional area than the contact portion. It comprises a component 172b, the bonding member 270b is formed to cover at least a portion of the second component (172b).

The first component 171b and the second component 172b of the first conductive portion 173b are integrally formed in a stepped manner, and in this embodiment, the first component 171b and the second component 172b. ), Steps are formed on all sides of the first configuration portion 171b.

6A and 6B illustrate another embodiment of the present invention, and only different points from the embodiment shown in FIGS. 5A and 5B will be described. FIG. 6A and 6B illustrate a second component 172c of the first conductive portion 173c. A hole 174c penetrating in the up and down directions is formed, and the joining member 270c is filled in the hole 174c. Referring to FIG. 6A, a bonding member 270c is positioned between the second component 172c and the protection circuit board 300, covering the top surface of the second component 172c, and the second component 172c. Is filled in the holes 174c penetrating in the up and down directions, and all of them are connected to each other, so that the connection force between the PTC element 170c and the protection circuit board 300 can be further strengthened.

7A and 7B illustrate another embodiment of the present invention, and only different points from the embodiment shown in FIGS. 4A and 4B will be described. FIG. 7A and 7B illustrate a second configuration portion 172d of the first conductive portion 173d. The hole 174d is formed in the side surface, and the joining member 270d is filled in this groove 174d. Therefore, the joining member 270d is positioned between the second component 172d and the protection circuit board 300, covering the top surface of the second component 172d, and formed on the side surface of the second component 172d. Filled in the groove 174d, and all of them are interconnected, the connection force between the PTC element 170d and the protective circuit board 300 can be further strengthened.

On the other hand, although not shown, as in the above-described embodiments, according to another embodiment, the PTC element includes a first conductive portion, a PTC main body portion, and a second conductive portion, and the first conductive portion of the PTC element includes: And a second component including a first component including a contact portion for contact and a large area portion having a larger cross-sectional area than the contact portion, wherein the joining member is formed to cover at least part of the second component. However, unlike the above-described embodiments, the first component and the second component do not form a step, but differ in that the outer surface of the second component is inclined or forms a curved portion. With regard to the content described in the above embodiments can be applied equally.

FIG. 8 shows another embodiment of the present invention. The PTC device 170e includes a first conductive portion 173e which is directly bonded to the protection circuit board 300 by the bonding member 270e, and one electrode of a bare cell. The second conductive portion 178e to be electrically connected, and the PTC body portion 176e positioned between the first conductive portion 173e and the second conductive portion 178e. Here, the area of the first conductive portion 173e of the PTC element is larger than that of the PTC body portion 176e, and the joining member 270e is formed to cover a part of the first conductive portion 173e.

In this case, a protrusion may be formed along the periphery of the PTC body 176e on the first conductive portion 173e so that the adhesive member 270e does not contact the PTC body 176e.

On the other hand, although the electrical connection between the electrode terminal having a negative polarity and the protective circuit board in the above embodiments is not shown, it may be connected to a conductive member of various forms.

Hereinafter, a pouch type secondary battery according to another aspect of the present invention will be described. However, description of the same contents as those of the can type secondary battery described above will be omitted.

The pouch type secondary battery includes a bare cell, a protective circuit board on which a protection circuit is formed, and a PTC device which is a safety device positioned between the protective circuit board and the bare cell.

The bare cell includes an electrode assembly and a pouch case that houses the electrode assembly and is sealed to expose a portion of the electrode tab drawn from the electrode assembly. Since the description of the structure of the bare cell is the same as that of the conventional bare cell, a description thereof will be omitted.

In addition, the protection circuit board is a substrate formed with a protection circuit for protecting the battery from overcharge or over discharge during charging and discharging, the description of this structure is the same as the structure of the conventional protection circuit board will be omitted.

The PTC device includes a first conductive portion directly bonded to the protective circuit board by a bonding member, a second conductive portion bonded to the electrode tab partially exposed in a sealed pouch, the first conductive portion and the second conductive portion. It comprises a PTC element having a PTC main body located between the parts.

Here, the first conductive portion of the PTC element comprises a first component including a contact portion in contact with the PTC body portion, and a second component portion including a large area portion having a larger cross-sectional area than the contact portion. The bonding member is formed to cover at least part of the second component.

Therefore, the path from the electrode tab of the bare cell to the protective circuit board is shortened, thereby reducing the electrical resistance. In addition, unlike the conventional structure, since the lead plate is unnecessary, the number of parts is reduced. Further, the joining member is formed so as to cover not only the contact surface between the first conductive portion and the protective circuit board but also the second component part, thereby enhancing the connection force between the PTC element and the protective circuit board.

A detailed description of the structure and shape of the PTC device of the pouch type secondary battery is the same as that of the PTC device of the can type secondary battery, and thus will be omitted.

According to the can-type and pouch-type secondary batteries according to the present invention, the PTC element located between the bare cell and the protective circuit board can operate smoothly at the designed temperature, and the time and cost required for the battery manufacturing process by reducing unnecessary components. This saves cost and maximizes the space efficiency between the bare cell and the protection circuit board, enabling a slim pack design.

Although the present invention has been described with reference to the illustrated embodiments, it is merely exemplary, and the present invention may encompass various modifications and equivalent other embodiments that can be made by those skilled in the art. Will understand.

Claims (28)

A bare cell having an electrode assembly, a can housing the electrode assembly, and a cap assembly coupled to an open upper portion of the can; A protection circuit board on which a protection circuit is formed; And A first conductive portion directly bonded to the protective circuit board, a second conductive portion bonded to one component of the cap assembly electrically connected to one electrode of the electrode assembly, the first conductive portion and the second conductive portion A can type secondary battery comprising a PTC element having a PTC main body positioned between the portions. The method of claim 1, And the first conductive portion is a plate type, and an upper surface thereof is directly bonded to the protection circuit board. The method of claim 1, The can-type secondary battery of claim 1, wherein the first conductive portion is soldered to the protective circuit board. The method of claim 3, wherein The can-type secondary battery, characterized in that the thickness of the first conductive portion is 0.2mm or more. The method of claim 1, The cap assembly may include a cap plate coupled to an open upper portion of the can, and the second conductive part may be welded to the cap plate. The method of claim 1, The cap assembly includes a cap plate coupled to an open upper portion of the can, and an electrode terminal installed through a terminal hole formed in the cap plate while placing a gasket on an outer surface for insulation from the cap plate. And the second conductive part is welded to the electrode terminal. The method according to claim 5 or 6, And the second conductive portion has a plate shape, and a lower surface thereof is directly welded to the cap plate or the electrode terminal. The method of claim 7, wherein The can-type secondary battery, characterized in that the thickness of the second conductive portion is 0.25mm or more. The method of claim 1, Can-type secondary battery, characterized in that the PTC body portion thickness is 0.4mm or more. The method of claim 1, The PTC device is a can-type secondary battery, characterized in that the cubic or cylindrical. A bare cell having an electrode assembly and a pouch case accommodating the electrode assembly and sealed to expose a portion of the electrode tab drawn from the electrode assembly; A protection circuit board on which a protection circuit is formed; And A PTC element having a first conductive portion directly bonded to the protective circuit board, a second conductive portion bonded to the electrode tab, and a PTC body portion positioned between the first conductive portion and the second conductive portion. Pouch-type secondary battery, characterized in that made. The method of claim 11, The first conductive part is a pouch type secondary battery, characterized in that the soldering bonded to the protective circuit board. The method of claim 11, The PTC device is a pouch type secondary battery, characterized in that the cubic or cylindrical. A bare cell having an electrode assembly, a can housing the electrode assembly, and a cap assembly coupled to an open upper portion of the can; A protection circuit board on which a protection circuit is formed; And A first conductive portion directly bonded to the protective circuit board by a bonding member, a second conductive portion electrically connected to one electrode of the bare cell, and a PTC positioned between the first conductive portion and the second conductive portion It comprises a PTC element having a main body, The first conductive portion of the PTC element comprises a first component including a contact portion in contact with the PTC body portion, and a second component portion including a large area portion having a larger cross-sectional area than the contact portion, and the joining member includes: Can-type secondary battery, characterized in that formed to cover at least a part of the second component. The method of claim 14, The can-type secondary battery of claim 1, wherein the first component and the second component are formed integrally with each other. The method of claim 15, The can-type secondary battery, characterized in that the step is formed only on both the left and right sides of the first component and the second component. The method of claim 15, The can-type secondary battery, wherein the first component and the second component are formed with steps at all sides of the first component. The method of claim 15, The can-type secondary battery, characterized in that the hole penetrating the second component in the vertical direction, the hole is filled with the bonding member. The method of claim 15, The can-type secondary battery, characterized in that the groove is formed on the side of the second component portion, the bonding member is filled in the groove. The method of claim 14, Can-type secondary battery, characterized in that the outer surface of the second component is inclined or forming a curved portion. The method of claim 14, The joining member is a can-type secondary battery, characterized in that the solder paste. The method of claim 14, And the bonding member is interposed between the second component and the protective circuit board. The method of claim 14, The joining member is a can-type secondary battery, characterized in that the contact with the PTC body portion. The method of claim 14, And the second conductive part is joined to one part of the cap assembly electrically connected to one electrode of the electrode assembly. The method of claim 24, The cap assembly may include a cap plate coupled to an open upper portion of the can, and the second conductive part may be welded to the cap plate. The method of claim 24, The cap assembly includes a cap plate coupled to an open upper portion of the can, and an electrode terminal installed through a terminal hole formed in the cap plate while placing a gasket on an outer surface for insulation from the cap plate. And the second conductive part is welded to the electrode terminal. A bare cell having an electrode assembly, a can housing the electrode assembly, and a cap assembly coupled to an open upper portion of the can; A protection circuit board on which a protection circuit is formed; And A first conductive portion directly bonded to the protective circuit board by a bonding member, a second conductive portion electrically connected to one electrode of the bare cell, and a PTC positioned between the first conductive portion and the second conductive portion It comprises a PTC element having a main body, The area of the first conductive portion of the PTC element is larger than the area of the PTC body portion, the bonding member is formed so as to cover a portion of the first conductive portion. A bare cell having an electrode assembly and a pouch case accommodating the electrode assembly and sealed to expose a portion of the electrode tab drawn from the electrode assembly; A protection circuit board on which a protection circuit is formed; And And a first conductive portion directly bonded to the protective circuit board by a bonding member, a second conductive portion bonded to the electrode tab, and a PTC body portion positioned between the first conductive portion and the second conductive portion. Including PTC element, The first conductive portion of the PTC element comprises a first component including a contact portion in contact with the PTC body portion, and a second component portion including a large area portion having a larger cross-sectional area than the contact portion, and the joining member includes: A pouch type secondary battery, characterized in that formed to cover at least a part of the second component.

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