KR102134648B1 - Secondary battery - Google Patents

Abstract

The present invention relates to a secondary battery capable of removing the beading process in the manufacturing process.
In addition, the present invention is a secondary battery including an electrode assembly, a can member for receiving the electrode assembly therein, and a top cap assembly blocking an opening of the can member, wherein the can member is provided at a bottom portion and an edge portion of the bottom portion. It includes a wall surface portion extending upwardly, the top cap assembly is located between the housing portion forming the inner circumference of the top cap assembly and the housing portion and the wall portion, and is adhered to both the housing portion and the wall portion by heat It characterized in that it comprises a gasket portion.

Description

Secondary battery {SECONDARY BATTERY}

The present invention relates to a secondary battery, and more particularly, to a secondary battery capable of removing a beading process in a manufacturing process.

Cells (cells) that generate electric energy through physical or chemical reactions of materials and supply power to the outside are unable to acquire AC power supplied to buildings depending on the living environment surrounded by various electric and electronic devices. It is used when the case or DC power is needed.

Among these batteries, primary and secondary batteries, which are chemical batteries using chemical reactions, are generally used, and primary batteries are commonly referred to as batteries, and are consumable batteries. In addition, the secondary battery is a rechargeable battery that is manufactured using a material in which many redox processes between a current and a material are repeated. When a reduction reaction is performed on a material by electric current, the power is charged and the oxidation reaction on the material is performed. When performed, the power is discharged, and electricity is generated while the charge-discharge is repeatedly performed.

On the other hand, the lithium ion battery of the secondary battery is coated with an active material on a positive electrode conductive foil and a negative electrode conductive foil, respectively, with a constant thickness, and a separation membrane is interposed between the two conductive foils to form a plurality of jelly rolls or a cylindrical shape several times. It is manufactured by storing the electrode assembly produced by winding and storing it in a cylindrical or square can, pouch, etc. and sealing it.

Korean Patent Publication No. 10-2011-0095118 discloses a conventional secondary battery.

Such a conventional secondary battery is configured to bead the upper portion of the can to couple the top cap assembly closing the opening of the can to the can.

However, in the process of forming a bead on the can, there is a problem in that various deterioration of battery performance such as low voltage occurs due to foreign matter.

In addition, according to the gasket performance of the secondary battery, the sealing of the secondary battery is not completely performed, which may cause a leak.

In addition, there is a problem in that the performance of the top cap assembly is damaged due to pressure applied in the process of beading the secondary battery and the performance is changed.

Therefore, the present invention was devised to solve the above problems, and an object of the present invention is to provide a secondary battery capable of removing a beading process in a secondary battery manufacturing process.

The secondary battery according to the present invention is a secondary battery including an electrode assembly, a can member accommodating the electrode assembly therein, and a top cap assembly blocking an opening of the can member, wherein the can member includes a bottom portion and the bottom portion. It includes a wall surface portion extending upward from the rim portion, the top cap assembly is located between the housing portion forming the inner circumference of the top cap assembly and the housing portion and the wall portion, both the housing portion and the wall portion by heat It characterized in that it comprises a gasket portion to be adhered to.

The wall surface portion may extend straight in an upward direction from the edge portion of the bottom portion.

The top cap assembly is stacked on the cap plate and the cap plate through which the exhaust hole is formed, and a vent member provided with a notch for cutting gas when the pressure inside the can member increases, and the cap plate and the vent member together. It may further include a current blocking filter stacked on the inner gasket and the vent member to be wrapped and electrically connected to the electrode assembly and shorted when the pressure inside the can member is shorted to block current.

The housing part may cover the inner gasket and the outer surfaces of the current blocking filter.

The housing part is made of aluminum (Al), and the can member may be made of iron (Fe) plated with nickel (Ni).

The gasket portion may be made of a polymer material modified to have polarity.

The polymer material may be polypropylene maleic anhydride.

A portion of the gasket portion may be bent to support a portion of the bottom surface of the housing portion.

The gasket portion may have an inner surface of the gasket portion heat-sealed to the housing portion and an outer surface of the gasket portion heat-sealed to the wall portion.

The housing portion may have a through hole.

According to the present invention, there is an effect to minimize the occurrence of foreign matter during the manufacturing process by removing the beading process in the manufacturing process.

According to the present invention, there is an effect of minimizing the deformation of the top cap assembly by removing the beading process in the manufacturing process.

According to the present invention, the top cap assembly is adhered to the can member by heat, thereby improving the sealing property.

According to the present invention, the top cap assembly is adhered to the can member by heat, thereby simplifying the production process and reducing production cost and time.

According to the present invention, the gasket is made of a polymer material modified to have polarity, thereby maximizing the adhesion between the metal member and the can member.

1 is a view showing a cross-sectional view of a portion of a secondary battery according to an embodiment of the present invention, with a top cap assembly installed in order to show main parts.
FIG. 2 is a partially enlarged view of a portion in which the gasket part is bonded to the vent member and the can member by heat in FIG.
3 is a view showing a cross-sectional view of a portion of a secondary battery according to another embodiment of the present invention, with a top cap assembly installed in order to show main parts.
FIG. 4 is a partially enlarged view of the gasket portion of FIG. 3, partially enlarged by a portion bonded to the vent member and the can member by heat.
5 is a flowchart sequentially showing a method for manufacturing a secondary battery according to the present invention.

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

The terms or words used in the present specification and claims should not be interpreted as being limited to ordinary or dictionary meanings, and the inventor can appropriately define the concept of terms in order to explain his or her invention in the best way. Based on the principle of being present, it should be interpreted as meanings and concepts consistent with the technical spirit of the present invention. Therefore, the embodiments shown in the embodiments and the drawings described in this specification are only the most preferred embodiments of the present invention and do not represent all of the technical spirit of the present invention, and thus can replace them at the time of application. It should be understood that there may be equivalents and variations.

In the drawings, the size of each component or a specific part constituting the component is exaggerated, omitted, or schematically illustrated for convenience and clarity of explanation. Therefore, the size of each component does not entirely reflect the actual size. When it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the description will be omitted.

1 is a view showing a cross-sectional view of a portion of a secondary battery according to an embodiment of the present invention, with a top cap assembly installed in order to show main parts.

As shown in Figure 1, the secondary battery according to an embodiment of the present invention is an electrode assembly (1), the can member (3) for receiving the electrode assembly (1) therein and the can member (3) In the secondary battery including the top cap assembly 100 for blocking the opening, the can member 3 includes a bottom part 3a and a wall surface part 3b extending upwardly from an edge portion of the bottom part 3a. Included, the top cap assembly 100 is located between the housing portion 150 and the housing portion 150 and the wall surface portion 3b forming an inner circumference of the top cap assembly 100, the heat is the It includes a gasket portion 140 that is adhered to both the housing portion 150 and the wall portion (3b).

The electrode assembly 1 can be produced by laminating a positive electrode coated with a positive electrode active material, a negative electrode coated with a negative electrode active material, and a separator interposed between the positive electrode and the negative electrode multiple times.

However, the present invention is not limited to this, and the electrode assembly 1 may also be manufactured by winding a laminate in which a positive electrode, a separator, and a negative electrode are stacked in the form of a jelly roll.

The positive electrode may be an aluminum plate, and may include a positive electrode active material portion coated with a positive electrode active material, and a positive electrode non-coated portion not coated with a positive electrode active material.

The positive electrode active material may be a lithium-containing transition metal oxide such as LiCoO2, LiNiO2, LiMnO2, or LiMnO4 or a lithium chalcogenide compound.

The positive electrode active material portion is formed, for example, by applying a positive electrode active material to a portion of at least one surface of the aluminum plate, and the remaining portion of the aluminum plate without the positive electrode active material may be a positive electrode non-coated portion.

The negative electrode may be a copper plate, and may include a negative electrode active material portion coated with a negative electrode active material and a negative electrode non-coated portion not coated with a negative electrode active material.

The negative electrode active material may be crystalline carbon, amorphous carbon, carbon composite, carbon material such as carbon fiber, lithium metal or lithium alloy, and the like.

The negative electrode active material portion is formed, for example, by applying a negative electrode active material to a portion of at least one surface of the copper plate, and the remaining portion of the copper plate without the negative electrode active material may be a negative electrode non-coated portion.

The separator may be any one selected from the group consisting of, for example, polyethylene (PE), polystyrene (PS), polypropylene (PP), and copolymers of polyethylene (PE) and polypropylene (PP). It can be prepared by coating a polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP co-polymer).

The can member 3 is a container made of a metal material having an open top shape in a round or square lithium ion secondary battery, and is light and easy to cope with corrosion, plated with aluminum (Al) or nickel (Ni), etc. (Fe) can be used.

In the secondary battery according to an embodiment of the present invention, the gasket part 140 positioned between the housing part 150 and the wall part 3b is thermally applied to both the housing part 150 and the wall part 3b. Bonded, this configuration can achieve a double sealing property to achieve the complete sealing property of the battery.

Since the adhesion by the heat is a method of being firmly attached without a gap, accordingly, a structure such as a beading portion of an indented shape provided in a conventional cylindrical battery does not need to be made any more, and crimping to form such a structure The (crimping) process may not be performed.

Unlike the conventional secondary battery, the can member 3 of the present invention does not have a beading portion formed on the wall surface portion 3b.

As a result, in the secondary battery according to an embodiment of the present invention, the can member 3 forms a cylinder having an open shape approximately upward, and the wall surface portion 3b of the can member 3 has a bottom portion 3a. ) Can be formed to extend straight upward from the edge portion.

By removing the beading process, there is no need to perform a physical indentation process, so it has the effect of minimizing the occurrence of foreign matters during the manufacturing process, can minimize the deformation of the top cap assembly 100, and blocks the possibility of cracking due to the deformation pressure. Sealability can be improved, and production costs and time are reduced as the production process is simplified.

In addition, in the secondary battery according to an embodiment of the present invention, since the double sealing can be implemented inside and outside the gasket portion 140, the inside and outside of the battery can be more surely blocked.

The can member 3 becomes a container of the electrode assembly 1 and an electrolyte solution (not shown), and the electrode assembly 1 is attached to the can member 3 through the open top of the can member 3, that is, the top opening. After insertion, the upper opening of the can member 3 is sealed by the top cap assembly 100.

The top cap assembly 100 further includes a protrusion 111 protruding outwardly in the center and a cap plate 110 through which an exhaust hole 115 is formed around the protrusion 111.

And as shown in Figure 1 includes a vent member 120 which is stacked on the bottom surface of the cap plate 110 and provided with a notch 123 that is cut when the pressure inside the can member 3 increases.

The vent member 120 has a notch portion 123 of the vent member 120 is cut by the gas inside the can member 3 when the pressure inside the can member 3 increases, the gas inside the can member 3 can Let the member 3 be discharged to the outside.

And includes an inner gasket 160 that is formed to surround the outer surface of the rim portion of the cap plate 110 and the outer surface of the rim of the vent member 120 together to mutually couple the cap plate 110 and the vent member 120. do.

In addition, as shown in FIG. 1, the current blocking filter 130 is further stacked on the bottom surface of the vent member 120 and electrically connected to the electrode assembly 1.

The current blocking filter 130 is short-circuited when the pressure inside the can member 3 increases when it exceeds a certain pressure, so that the current does not flow, and when the pressure inside the can member 3 continues to increase after the short-circuit, the notch portion 123 ) Is cut to discharge the gas inside the can member 3 to the outside.

And it includes a housing portion 150 that surrounds the outer surfaces of the inner gasket 160 and the current blocking filter 130 to form an inner circumference of the top cap assembly 100.

The housing unit 150 may be formed of aluminum (Al) material, and the through hole 151 is perforated to allow gas to move when the pressure inside the can member 3 increases.

In addition, the inner surface is heat-sealed to the housing portion 150 so as to wrap from the periphery of the housing portion 150 to a part of the bottom surface, and the outer surface includes a gasket portion 140 that is heat-sealed to the inner surface of the can member 3.

The gasket portion 140 is made of a polymer material modified to have polarity, and is adhered to the housing portion 150 made of aluminum and the can member 3 made of nickel-plated iron by heat.

A polymer material modified to have polarity may be, for example, a polypropylene maleic anhydride.

In the case of polypropylene maleic anhydride, it has a very good adhesion effect with metal by heat, and has excellent heat resistance, so it has a higher melting point than the heat that can be generated in the environment in which the secondary battery is used. It is an optimal material for the gasket portion 140 of the present invention.

However, the material of the gasket portion 140 is not necessarily limited thereto, and other materials generally known may be used as long as it is a polymer material modified to have polarity.

FIG. 2 is a partially enlarged view of a portion in which the gasket part is bonded to the vent member and the can member by heat in FIG.

As illustrated in FIG. 2, the secondary battery according to another embodiment of the present invention has a shape in which the gasket portion 140 is bent only once inside.

That is, the gasket portion 140 has an L-shape in cross section, and the inner side is adhered to the housing portion 150 by heat, while the lower bending portion of the gasket portion 140 supports the bottom surface of the housing portion 150.

Thus, when the gasket portion 140 forms an L-shape, the injection molding time is reduced by simplifying the shape compared to a conventional gasket, and the amount of raw materials can be reduced, thereby improving productivity and reducing costs.

The polymer material modified to have polarity is excellent in adhesion to metal materials such as nickel and aluminum when heated.

Table 1 shows experimental data that can compare the adhesive strength of a polymer material modified to have polarity and nickel metal to be adhered by heat to that of a general polypropylene (PP) material and nickel metal.

Polymer material A (PE series) modified to have polarity Polymer material B (POE series) modified to have polarity Polymer material D modified to have polarity (PP series) Polypropylene material Adhesion with nickel plated iron material (kgf/2cm)
15-25 kgf/2cm
20 kgf/2cm
18 kgf/2cm
0 kgf/2cm

As shown in Table 1, the polymer material modified to have polarity has excellent adhesion to nickel metal by heat (15 kgf/2cm to 25 kgf/2cm), while polypropylene material does not have adhesion to nickel metal even when heated.

Therefore, the present invention is made of a polymer material modified to have a polarity such as polypropylene maleic anhydride as the material of the gasket portion 140 so as to be firmly adhered to the nickel plated can member 3 by heat.

That is, in the present invention, the gasket portion 140 is firmly attached to the can member 3 by heat without forming a beading portion on the can member 3 when the gasket portion 140 is coupled to the can member 3. To be attached.

As described above, the polymer material modified to have polarity can secure adhesion to metal by heat. In one embodiment, the aluminum material of the vent member 120 or the nickel material of the can member 3 is plated with iron material. It has strong adhesion.

3 is a view showing a cross-sectional view of a portion of a secondary battery according to another embodiment of the present invention, with a top cap assembly installed in order to show main parts.

3, the top cap assembly 100 of the secondary battery according to another embodiment of the present invention includes a cap plate 110 through which an exhaust hole 115 is formed.

And as shown in Figure 3 is coupled to the rim of the cap plate 110 on the bottom surface of the cap plate 110, when the pressure inside the can member (3) is cut by the pressure of the gas inside the can member (3) outside Further comprising a vent member 120 is provided with a notch 123 for discharging to.

Here, the vent member 120 may be made of aluminum (Al) material, and the rim may be bent to surround the rim of the cap plate 110 and coupled to the cap plate 110.

And as shown in Figure 3 further includes a current blocking filter 130 that is in close contact with the bottom surface of the vent member 120 and is electrically connected to the electrode assembly 1.

When the pressure inside the can member 3 increases, the current blocking filter 130 is shorted to block the current.

In addition, the gasket portion 140 of the top cap assembly 100 may be formed to surround the outer surfaces of the vent member 120 and the current blocking filter 130, particularly the vent member 120 on the inner surface of the gasket portion 140. And the current blocking filter 130 is provided with a support end portion 141 is provided with a step is formed in each of the seating portion may be to support the bottom surface of the vent member 120 and the current blocking filter 130, respectively.

In addition, the gasket portion 140 is made of a polymer material modified to have polarity, and is adhered to a bent member 120, which is an aluminum material and a can member 3, which is a nickel-plated iron material by heat.

FIG. 4 is a partially enlarged view of the gasket portion of FIG. 3, partially enlarged by a portion bonded to the vent member and the can member by heat.

As shown in FIG. 4, the gasket 140 has an inner surface in close contact with the vent member 120 by heat, and an outer surface in close contact with the can member 3 by heat. ).

5 is a flowchart sequentially showing a method for manufacturing a secondary battery according to the present invention.

Hereinafter, a method of manufacturing a secondary battery according to the present invention will be described in detail with reference to the drawings.

As shown in Figure 5, the method of manufacturing a secondary battery according to the present invention is a positive electrode active material is coated positive electrode and a negative electrode active material is coated a negative electrode and a separator interposed between the positive electrode and the negative electrode is laminated a plurality of times or the positive electrode and the separator and the negative electrode It comprises an electrode assembly step (S1) of assembling the electrode assembly by winding the laminated body in the form of a jelly roll.

And it includes a receiving step (S2) for receiving the electrode assembly and the electrolytic solution into the inside of the can member through the opening of the can member.

And it includes a closing step (S3) to install the top cap assembly to the opening of the can member to close the opening of the can member.

And it includes an adhesive step (S4) for bonding the top cap assembly to the can member by heat.

In the bonding step (S4), a method of thermally bonding the top cap assembly to the can member uses any one or more of vibration, infrared, hot press, and laser.

Here, the method of thermally bonding the top cap assembly to the can member by vibration has an advantage in that a heat source is not required and components of the secondary battery are not damaged by the heat source.

In addition, the method of thermally bonding the top cap assembly to the can member with infrared rays does not require a heat source, and has a merit in that only a desired portion is specified to transfer heat and adhere.

In addition, the method of attaching the top cap assembly to the can member by heat by hot press is capable of polymer melting and adhesion by directly transferring heat, and the device structure is simple, so it is easy to install the hot press device in the secondary battery manufacturing process. Has an advantage.

In addition, the method of thermally bonding the top cap assembly to the can member with a laser has the advantage of enabling precise adhesion by allowing heat transfer to a local area.

According to the present invention as described above, by removing the beading process in the manufacturing process, there is an effect to minimize the occurrence of foreign matter during the manufacturing process.

In addition, there is an effect to minimize the deformation of the top cap assembly by removing the beading process in the manufacturing process.

In addition, there is an effect of improving the sealability by bonding the top cap assembly to the can member by heat.

In addition, by attaching the top cap assembly to the can member by heat, the production process is simplified and the production cost and time are reduced.

In addition, the gasket is made of a polymer material modified to have polarity, and thus has an effect of maximizing the adhesion between the metal member and the can member.

In addition, by applying heat to any one or more of vibration, infrared, hot press, laser, the top cap assembly is adhered to the can member, thereby effecting heat adhesion in an optimal manner.

As described above, the secondary battery according to the present invention has been described with reference to the exemplified drawings, but the present invention is not limited by the above-described embodiments and drawings, and is usually within the technical field to which the present invention pertains within the scope of the claims. Various modifications and variations are possible by those with knowledge of.

1: electrode assembly
3: Can absence
3a: bottom
3b: wall part
100: top cap assembly
110: cap plate
111: protrusion
115: exhaust hole
120: vent member
123: Notch
130: current cut filter
140: gasket portion
141: support end
150: housing
160: internal gasket

Claims (10)

Electrode assembly 1;
A can member (3) accommodating the electrode assembly (1) therein; And
A top cap assembly 100 closing the opening of the can member 3; In the secondary battery comprising a,
The can member 3 includes a bottom portion 3a and a wall surface portion 3b extending upwardly from an edge portion of the bottom portion 3a,
The top cap assembly 100 includes a housing portion 150 forming an inner circumference of the top cap assembly 100.
It is located between the housing portion 150 and the wall surface portion (3b), and includes a gasket portion 140 that is adhered to both the housing portion 150 and the wall surface portion (3b) by heat,
The wall surface portion 3b extends straight from the edge portion of the bottom portion 3a in an upward direction,
The gasket portion 140 has a shape that is bent only once inside, and the cross section forms an L-shape,
The top cap assembly 100,
The exhaust plate 115 and the cap plate 110 is formed through
A vent member 120 which is stacked on the cap plate 110 and is provided with a notch 123 that is cut off and discharges gas when the pressure inside the can member 3 increases.
An inner gasket 160 that wraps and couples the cap plate 110 and the vent member 120 together, and
It is laminated on the vent member 120 and is electrically connected to the electrode assembly 1 and further includes a current blocking filter 130 that is shorted when the pressure inside the can member 3 increases to block current.
The housing 150 surrounds the inner gasket 160 and the outer surfaces of the current blocking filter 130,
A portion of the gasket part 140 is bent so that a part of the bottom surface of the housing part 150 is supported, but the upper surface of the housing part 150 is not supported. delete delete delete The method according to claim 1,
The housing part 150 is made of aluminum (Al), and the can member 3 is a secondary battery, characterized in that nickel (Ni) is plated iron (Fe). The method according to any one of claims 1 and 5,
The gasket portion 140 is a secondary battery characterized in that it is made of a polymer material modified to have a polarity. The method according to claim 6,
The polymer material is a secondary battery characterized in that the polypropylene maleic anhydride (polypropylene maleic anhydride). delete The method according to claim 1,
The gasket part 140 is characterized in that the inner surface of the gasket part 140 is heat-sealed to the housing part 150 and the outer surface of the gasket part 140 is heat-sealed to the wall part 3b. Secondary battery. The method according to claim 1,
The housing unit 150 is a secondary battery, characterized in that the through-hole 151 is perforated.

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