KR102663125B1 - Pouch and secondary battery - Google Patents

Abstract

One embodiment of the present invention includes a lower pouch; and an upper pouch disposed on an upper side of the lower pouch, wherein side folding portions are formed on both sides of the lower pouch and extend wider than the width of the upper pouch.
In this way, the manufacturing process of the pouch-type secondary battery proceeds in the order of primary folding - sealing - secondary folding using upper and lower pouches with different widths, so that insulating tapes such as Kapton tape are applied to both sides of the pouch. It is possible to provide sufficient insulation effect while omitting the insulation work used.

Description

Pouches for secondary batteries and pouch-type secondary batteries {POUCH AND SECONDARY BATTERY}

The present invention relates to a pouch for secondary batteries and a secondary battery using the same.

In recent secondary batteries, the method of using a pouch as an exterior material to seal the electrode assembly has been in the spotlight. Using a pouch not only increases the energy density per unit weight and volume, makes the battery thinner and lighter, but also reduces the material cost of the exterior material, which has many advantages.

However, in order to form a battery with a higher capacity, a pouch-type secondary battery must contain electrodes and electrolytes to have a larger capacity in a relatively small pouch. To this end, a pouch that is not directly related to battery capacity or storage function must be used. There is a demand to gradually reduce the peripheral sealing portion.

This is because by reducing the width of the sealing part of the pouch-type secondary battery, an electrode assembly with a larger capacity can be accommodated inside, and the sealing part itself, which is not directly related to capacity, can be reduced. For this reason, if the width of the sealing part is reduced, a secondary battery with a higher capacity can be manufactured compared to a pouch-type secondary battery of the same size.

However, as the absolute sealing area decreases due to a decrease in the width of the sealing part, the sealing reliability of the pouch-type secondary battery may decrease, and moisture may infiltrate from the outside, reducing long-term storage stability, which has the disadvantage of deteriorating the performance of the battery.

Accordingly, recently, a technology has been used to reduce the volume by bending both sealing parts in the direction of the inner space of the pouch without reducing the width of the sealing part itself.

Meanwhile, pouch-type secondary batteries are manufactured with a metal layer sandwiched between insulating layers, and exposure of the metal layer at the end of the pouch may cause insulation breakdown, and moisture, etc., may penetrate through the heat-sealed portion of the laminate sheet. There is a possibility that it can be done.

In this regard, since the upper and lower pouches of existing secondary batteries have the same size, the edges of the upper and lower pouches are sealed using a method such as heat fusion, and then the sides of the upper and lower pouches are folded. Then, an attempt was made to insulate the end of the pouch using an insulating tape such as Kapton tape.

Korean Patent Publication No. 10-2018-0049573

Embodiments of the present invention provide a pouch for secondary batteries and a pouch-type secondary battery that can lead to simplification of insulation and sealing operations.

The object of the present invention is not limited to the above, and other objects and advantages of the present invention that are not mentioned can be understood by the following description.

A pouch for a secondary battery according to an embodiment of the present invention includes a lower pouch; and an upper pouch disposed on an upper side of the lower pouch, wherein side folding portions may be formed to extend wider than the width of the upper pouch on both sides of the lower pouch.

In an embodiment of the present invention, the lower pouch further includes an upper folding portion provided at the upper portion, and the upper folding portion may be bent to surround the upper side of the upper pouch.

In an embodiment of the present invention, the upper pouch and the lower pouch are formed as one piece, and a bent portion may be formed at the boundary between the upper pouch and the lower pouch.

In an embodiment of the present invention, the upper pouch and the lower pouch are formed as separate types, a lower folding part extends from the lower part of the lower pouch, and the lower folding part may be bent to surround the lower part of the upper pouch.

In addition, a pouch-type secondary battery according to an embodiment of the present invention includes an electrode assembly; It includes a lower pouch and an upper pouch disposed on an upper side of the lower pouch, and side folding portions may be formed to extend wider than the width of the upper pouch on both sides of the lower pouch.

In an embodiment of the present invention, the lower pouch further includes an upper folding portion provided at the upper portion, and the upper folding portion may be bent to surround the upper side of the upper pouch.

In an embodiment of the present invention, the secondary battery includes an electrode tab exposed to the outside of the pouch, and the upper folding part may be arranged so as not to interfere with the electrode of the secondary battery.

According to an embodiment of the present invention, the manufacturing process of a pouch-type secondary battery is carried out in the order of primary folding - sealing - secondary folding using upper and lower pouches having different widths, so that Kapton tape is applied to both sides of the pouch. It is possible to provide sufficient insulation effect while omitting the insulation work using insulation tape.

In addition, according to an embodiment of the present invention, sufficient insulation effect can be secured without using an insulating tape such as Kapton tape, thereby leading to simplification of insulation and sealing work and reducing overall manufacturing costs.

The effects of the present invention are not limited to the effects described above, and should be understood to include all effects that can be inferred from the configuration of the invention described in the detailed description or claims of the present invention.

Figure 1 is a plan view showing a pouch for a secondary battery according to a first embodiment of the present invention.
Figure 2 is a schematic diagram showing the folding process of a pouch-type secondary battery according to the first embodiment of the present invention.
Figure 3 is a plan view showing a pouch for a secondary battery according to a second embodiment of the present invention.
Figure 4 is a schematic diagram showing the folding process of the pouch-type secondary battery according to the second embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. The present invention may be implemented in many different forms and is not limited to the embodiments described herein.

In order to clearly explain the present invention, detailed descriptions of parts unrelated to the essence of the present invention may be omitted, and identical or similar components may be assigned the same reference numerals throughout the specification.

Additionally, when a part is said to “include” a certain component, this means that it may further include other components, rather than excluding other components, unless specifically stated to the contrary. Technical terms used herein are only intended to refer to specific embodiments and are not intended to limit the present invention, and unless otherwise defined herein, will be understood by a person of ordinary skill in the art to which the present invention pertains. It can be interpreted as a concept.

Figure 1 is a plan view showing a pouch for a secondary battery according to a first embodiment of the present invention.

Referring to FIG. 1, the pouch 120 for a secondary battery according to the first embodiment provides a space for storing an electrode assembly and includes an upper pouch 121 and a lower pouch 122. The upper pouch 121 and the lower pouch 122 are formed as one piece, and a bent portion S is formed at their boundary.

An internal space 121a is formed in at least one of the upper pouch 121 and the lower pouch 122 to accommodate the electrode assembly 110 (see FIG. 2), and the internal space 121a accommodates the electrode assembly and the electrolyte solution. do. In the embodiment of the present invention, the internal space 121a is formed in the upper pouch 121, but it does not need to be limited thereto. That is, the internal space 121a may be formed in the lower pouch 122, or may be formed in both the upper pouch 121 and the lower pouch 122.

The pouch 120 protects internal components such as the electrode assembly and the electrolyte, and may include a metal layer (M) such as aluminum to supplement electrochemical properties caused by the electrode assembly and the electrolyte and to dissipate heat. The metal layer (M) may be interposed between the insulating layers (I) formed of an insulating material to ensure electrical insulation from components inside the secondary battery, such as the electrode assembly and electrolyte, or other components outside the secondary battery.

Side folding portions 122a are formed on both sides of the lower pouch 122. That is, the width of the lower pouch 122 is formed to be wider than the width of the upper pouch 121. Accordingly, side folding portions 122a are formed on both sides of the lower pouch 122 so as to protrude outward than the width of the upper pouch 121.

An upper folding portion 122b is formed at the top of the lower pouch 122. The upper folding portion 122b is arranged so as not to interfere with the electrode tab of the electrode assembly. For example, a positive electrode tab and a negative electrode tab may be formed in the electrode assembly, and when both the positive electrode tab and the negative electrode tab are formed to protrude in the same direction on one side of the electrode assembly, the upper folding portion 122b is the electrode tab of the electrode assembly. Except for this formed area, it may be formed to protrude upward from the lower pouch 122. At this time, the length of the upper pouch 121 may be the same as the length of the lower pouch 122 excluding the upper folding portion 122b.

Therefore, when the electrode assembly is accommodated in the inner space of the upper pouch 121 and the area folded by the side folding part and the upper folding part is sealed using a sealing tool, a secondary battery having a width of a specified size is manufactured. .

At this time, for convenience of explanation, when referring to FIG. 1, the direction in which the upper folding portion 122b is formed when the upper pouch 121 and the lower pouch 122 are combined is upward, and the bent portion S on the opposite side is the upward direction. The direction in which it is formed is called the downward direction.

Figure 2 is a schematic diagram showing the folding and sealing process of a pouch-type secondary battery according to the first embodiment of the present invention.

Referring to FIG. 2, the pouch-type secondary battery according to the first embodiment includes an electrode assembly 110 and a pouch 120.

The electrode assembly 110 is composed of a positive electrode plate and a negative electrode plate arranged with a separator in between. The electrode assembly 110 is provided with an electrode tab 111. That is, a positive electrode tab may be attached to the positive electrode plate of the electrode assembly 110, and a negative electrode tab may be attached to the negative electrode plate of the electrode assembly 110.

The positive and negative tabs may protrude to the outside of the pouch 120 to form positive and negative terminals. At this time, the positive and negative tabs are not directly exposed to the outside of the pouch 120, but are connected to other components such as the positive and negative leads, and the positive and negative leads may be exposed to the outside of the pouch 120. .

Since the configuration of the pouch 120 is the same as that already described above with reference to FIG. 1, further detailed description will be omitted.

When the electrode assembly 110 is accommodated inside the pouch 120 and the upper pouch 121 is bent toward the lower pouch 122 based on the bent portion S at the approximate center of the pouch 120, the pouch 120 The secondary battery manufacturing process proceeds through a first folding step, a sealing step, and a second folding step.

The first folding step includes a first side folding step and a top folding step, as shown in (a) of FIG. 2.

The first side folding step is a step in which the side folding portions 122a provided on both sides of the lower pouch 122 are bent 180° toward the internal space so as to surround the sides of the upper pouch 121. Accordingly, the metal layer exposed at both ends of the upper pouch 121 is stably covered by the side folding portion 122a of the lower pouch 122 and is not exposed to the outside.

The upper folding step is a step of bending the upper folding portion 122b provided at the upper part of the lower pouch 122 by 180° toward the internal space to surround a portion of the upper side of the upper pouch 121. The upper folding parts 122b may be arranged alternately so as not to interfere with the electrode tabs 111 of the electrode assembly 110.

As shown in (b) of FIG. 2, the sealing step is a step of sealing the first folded side folding portion 122a and the upper folding portion 122b using heat fusion or the like to seal the internal space of the pouch. Additionally, the upper contact portion between the upper pouch 121 and the lower pouch 122 can be insulated and sealed using an insulating tape (T) such as terrace tape.

The second folding step is a step of bending the side folding portion 122a of the first folded lower pouch 122 again, as shown in (c) of FIG. 2. The final size and shape of the secondary battery can be determined by folding in the secondary folding step.

When the second folding step is performed, the side ends of the lower pouch 122 are bent toward the internal space. Accordingly, the metal layer on the side of the lower pouch 122, which was exposed to the outside, is also hidden. Therefore, it is possible to ensure the insulating state of the metal layer on the side of the lower pouch 122.

According to this embodiment of the present invention, the insulation or airtightness work on both sides of the pouch 120 can be completed through a single sealing operation performed between the first folding and the second folding.

That is, as in the embodiment of the present invention, when manufacturing a secondary battery using the upper pouch 121 and the lower pouch 122 of different widths, the pouch-type secondary battery is carried out in the order of primary folding - sealing - secondary folding. As the manufacturing process progresses, insulation work using an insulating tape such as Kapton tape on both sides of the pouch 120 can be omitted, thereby reducing the overall manufacturing cost.

However, when the width of the upper pouch 121 and the lower pouch 122 are the same, the manufacturing process of the secondary battery proceeds in the following order: sealing - primary side folding - side insulation by Kapton tape. In this case, secondary battery such as Kapton tape is used. Configuration is required, which may increase manufacturing costs.

Figure 3 shows a pouch for a secondary battery according to a second embodiment of the present invention. In the second embodiment, the same drawing numbers are assigned to the same components as those in the first embodiment.

Referring to FIG. 3, the pouch 130 for a secondary battery according to the second embodiment includes a lower pouch 132 and an upper pouch 131, and the lower pouch 132 and the upper pouch 131 are separated from each other. is provided.

An internal space 131a is formed in at least one of the upper pouch 131 and the lower pouch 132 to accommodate the electrode assembly 110 (see FIG. 4), and the internal space 131a accommodates the electrode assembly and the electrolyte solution. do.

Side folding portions 132a are formed to extend laterally on both sides of the lower pouch 132, and lower folding portions 132c are formed to extend downwardly on the lower side of the lower pouch 132. That is, the width of the lower pouch 132 is formed to be wider than the width of the upper pouch 131, and the length of the lower pouch 132 is formed to be longer than the length of the upper pouch 131.

An upper folding portion 132b is formed at the top of the lower pouch 132. The upper folding part 132b may be arranged so as not to interfere with the electrode tab of the electrode assembly.

Figure 4 is a schematic diagram showing the folding and sealing process of the pouch-type secondary battery according to the second embodiment of the present invention.

Referring to FIG. 4, the manufacturing method of the pouch-type secondary battery according to the second embodiment includes a primary folding step, a sealing step, and a secondary folding step.

That is, when the electrode assembly 110 is accommodated inside the pouch 130 and the upper pouch 131 is disposed correspondingly on the upper side of the lower pouch 132, the pouch 130 undergoes the first folding step, the sealing step, and the second step. The manufacturing process of secondary batteries proceeds through the folding step.

The first folding step includes a first side folding step, a top folding step, and a first bottom folding step, as shown in (a) of FIG. 4.

The first side folding step is a step in which the side folding portions 132a provided on both sides of the lower pouch 132 are bent 180° toward the internal space so as to surround the sides of the upper pouch 131. Accordingly, the metal layer exposed at both ends of the upper pouch 131 is covered by the side folding portion 132a of the lower pouch 132 and is not exposed to the outside.

The upper folding step is a step of bending the upper folding part 132b provided at the upper part of the lower pouch 132 by 180° toward the internal space to surround a portion of the upper side of the upper pouch 131.

The first lower folding step is a step in which the lower folding portion 132c provided on the lower side of the lower pouch 132 is bent 180° toward the internal space so as to surround the lower side of the upper pouch 131. Accordingly, the metal layer exposed at the bottom of the upper pouch 131 is covered by the lower folding part 132c of the lower pouch 132 and is not exposed to the outside.

As shown in (b) of FIG. 4, the sealing step is a step of sealing the first folded side folding portion 132a, upper folding portion 132b, and lower folding portion 132c by heat fusion or the like. Additionally, the upper contact portion between the upper pouch 131 and the lower pouch 132 can be insulated and sealed using an insulating tape (T) such as terrace tape.

The second folding step is a step of bending the side folding portion 132a and the lower folding portion 132c of the first folded lower pouch 132 again, as shown in (c) of FIG. 4. The final size and shape of the secondary battery can be determined by folding in the secondary folding step.

When the second folding step is performed, the side and bottom ends of the lower pouch 132 are bent toward the internal space. Accordingly, the metal layer on the side and bottom of the lower pouch 132, which was exposed to the outside, is also hidden. Therefore, it is possible to ensure the insulating state of the metal layers on the side and bottom sides of the lower pouch 132.

Meanwhile, the pouch-type secondary battery according to an embodiment of the present invention can be applied to a battery pack containing two or more secondary batteries.

Additionally, the pouch-type secondary battery according to an embodiment of the present invention can be applied to a device that includes a secondary battery as a power source.

For example, the device may be a computer, cell phone, wearable electronic device, power tool, electric vehicle (EV), hybrid electric vehicle, plug-in hybrid electric vehicle, electric two-wheeler, electric golf cart, or electric vehicle. It could be a storage device. Power storage devices can be applied to various fields and locations, such as smart grid systems for controlling power supply and demand or charging stations for electric vehicles.

Those skilled in the art to which the present invention pertains should understand that the present invention can be implemented in other specific forms without changing its technical idea or essential features, and that the embodiments described above are illustrative in all respects and not restrictive. Just do it.

The scope of the present invention is indicated by the claims described later rather than the detailed description, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention. .

100; secondary battery 110; electrode assembly
111; electrode tab
120, 130; pouch 121, 131; Upper pouch
121a, 131a; internal space 122, 132; Lower pouch
122a, 132a; Side folding parts 122b, 132b; Upper folding part
132c; lower folding part 123; bend

Claims (8)

In the pouch for secondary batteries,
Lower pouch;
It includes an upper pouch disposed on the upper side of the lower pouch,
On both sides of the lower pouch, side folding portions are formed extending wider than the width of the upper pouch,
It further includes an upper folding part provided at the upper part of the lower pouch, wherein the upper folding part is bent to surround the upper side of the upper pouch,
The upper folding part protrudes only in areas excluding the area where the electrode tab protrudes,
A pouch-type secondary battery wherein the upper folding part is arranged so as not to interfere with the electrode tab.
delete According to paragraph 1,
A pouch for a secondary battery in which the upper pouch and the lower pouch are formed as one piece, and a bent portion is formed at a boundary between the upper pouch and the lower pouch.
According to paragraph 1,
The upper pouch and the lower pouch are formed as separate types, a lower folding part is extended from the lower part of the lower pouch, and the lower folding part is bent to surround the lower part of the upper pouch.
In the pouch-type secondary battery,
electrode assembly;
It includes a lower pouch and an upper pouch disposed on the upper side of the lower pouch,
On both sides of the lower pouch, side folding portions are formed extending wider than the width of the upper pouch,
It further includes an upper folding part provided at the upper part of the lower pouch, wherein the upper folding part is bent to surround the upper side of the upper pouch,
The upper folding part protrudes only in areas excluding the area where the electrode tab protrudes,
The secondary battery includes an electrode tab exposed to the outside of the pouch, and the upper folding part is arranged so as not to interfere with the electrode of the secondary battery.
delete delete A battery pack containing two or more pouch-type secondary batteries according to claim 5.

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