KR20200012205A - Pouch and secondary battery - Google Patents

Abstract

Provided is a pouch for a secondary battery and a pouch type secondary battery. The pouch for a secondary battery according to an embodiment of the present invention comprises: a lower pouch; and an upper pouch disposed in an upper side of a lower pouch, wherein a side folding part is extended on both sides of the lower pouch to be wider than the width of the upper pouch. Therefore, a sufficient insulation effect can be provided to both sides of the pouch while omitting an insulation process using an insulating tape such as Kapton tape by manufacturing the pouch-type secondary battery in the order of primary folding, sealing and secondary folding by using the upper and lower pouches having different widths.

Description

Pouch and Secondary Battery for Secondary Battery {POUCH AND SECONDARY BATTERY}

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

BACKGROUND ART In recent years, a method of using a pouch as a packaging material for sealing an electrode assembly has been in the spotlight. The use of a pouch increases the energy density per unit weight and volume, makes the battery thinner and lighter, and also has advantages in that the material cost of the exterior material is low.

However, in order to form a higher capacity battery, the pouch type secondary battery must include an electrode and an electrolyte to have a larger capacity in a relatively small sized pouch. There is a need to gradually reduce the peripheral sealing portion.

This is because reducing the width of the sealing portion of the pouch-type secondary battery can accommodate the electrode assembly having a larger capacity therein, and reduce the sealing portion itself not directly related to the capacity. Therefore, if the width of the sealing portion is reduced, a secondary battery having a higher capacity than a pouch type secondary battery having the same size may be manufactured.

However, the sealing area of the pouch-type secondary battery may decrease while the sealing area is reduced due to the decrease in the width of the sealing part, and the moisture may penetrate from the outside, thereby deteriorating long-term storage stability.

Therefore, recently, a technique of reducing the volume by bending both sealing portions in the direction of the inner space of the pouch without reducing the width itself of the sealing portion has been used.

On the other hand, the pouch type secondary battery is manufactured in the form of a metal layer interposed between the insulating layer, the breakdown phenomenon may occur due to the exposed metal layer at the end of the pouch, moisture, etc. penetrates through the heat-sealed portion of the laminate sheet There is a possibility.

In this regard, since the size of the upper and lower pouches of the conventional secondary battery is the same, the edges of the upper and lower pouches are sealed by a method such as thermal fusion, and then the sides of the upper and lower pouches are folded. Subsequently, an insulation treatment on the end of the pouch was attempted using an insulation tape such as Kapton tape.

Korea Patent Publication 10-2018-0049573

Embodiments of the present invention provide a pouch for a secondary battery and a pouch type secondary battery capable of inducing a 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 which are not mentioned may be understood by the following description.

Secondary battery pouch according to an embodiment of the present invention, the lower pouch; And an upper pouch disposed on an upper side of the lower pouch, and side folding parts may be formed on both sides of the lower pouch to extend wider than the width of the upper pouch.

In an embodiment of the present invention, the lower pouch further includes an upper folding portion provided, 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 may be integrally formed, and a bent portion may be formed at a boundary portion between the upper pouch and the lower pouch.

In an embodiment of the present invention, the upper pouch and the lower pouch are formed in a separate type, the lower folding portion is formed extending from the lower portion of the lower pouch, the lower folding portion may be bent to surround the lower portion of the upper pouch.

In addition, the pouch-type secondary battery according to an embodiment of the present invention, the electrode assembly; And a lower pouch and an upper pouch disposed on an upper side of the lower pouch, wherein both sides of the lower pouch may have side folding portions extending wider than a width of the upper pouch.

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

According to an embodiment of the present invention, by using the upper pouch and the lower pouch having a different width in the order of manufacturing the pouch-type secondary battery in the order of primary folding-sealing-secondary folding, Kapton tape on both sides of the pouch A sufficient insulation effect can be given while eliminating the insulation work using an insulation tape such as the above.

In addition, according to the embodiment of the present invention, it is possible to ensure a sufficient insulation effect without using an insulating tape such as Kapton tape, thereby inducing the simplification of the insulation and sealing operations, and can reduce the overall manufacturing cost.

The effects of the present invention are not limited to the above-described effects, but should be understood to include all the effects deduced from the configuration of the invention described in the detailed description or claims of the present invention.

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

Hereinafter, with reference to the accompanying drawings will be described in detail an embodiment of the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

In order to clearly describe the present invention, parts irrelevant to the essence of the present invention may be omitted, and the same reference numerals may be assigned to the same or similar elements throughout the specification.

In addition, when a part is said to "include" a certain component, this means that it may further include other components, except to exclude other components unless otherwise stated. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention, unless otherwise defined herein, as understood by one of ordinary skill in the art to which the invention pertains. It can be interpreted as a concept.

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

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

At least one of the upper pouch 121 and the lower pouch 122 is formed with an inner space 121a for accommodating the electrode assembly 110 (refer to FIG. 2), and the electrode assembly and the electrolyte are accommodated in the inner space 121a. do. In the embodiment of the present invention, the inner space 121a is formed in the upper pouch 121, but is not limited thereto. That is, the inner 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 may include a metal layer M, such as aluminum, to protect internal components such as an electrode assembly and an electrolyte, and to supplement and dissipate electrochemical properties of the electrode assembly and the electrolyte and to dissipate heat. The metal layer (M) may be interposed between the insulating layer (I) formed of an insulating material in order to ensure electrical insulation with components inside the secondary battery, such as the electrode assembly and the electrolyte or other components outside the secondary battery.

Side folding parts 122a are formed at both sides of the lower pouch 122. That is, the width of the lower pouch 122 is formed wider than the width of the upper pouch 121. Therefore, side folding parts 122a are formed on both side surfaces of the lower pouch 122 so as to protrude outward from the width of the upper pouch 121.

The upper folding part 122b is formed on the lower pouch 122. The upper folding part 122b is disposed so as not to interfere with the electrode tab of the electrode assembly. For example, the positive electrode tab and the negative electrode tab may be formed in the electrode assembly. 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 part 122b is the electrode tab of the electrode assembly. Except for the formed portion, the lower pouch 122 may be formed to protrude upward. In this case, the length of the upper pouch 121 may be equal to the length of the lower pouch 122 except for the upper folding part 122b.

Therefore, when the electrode assembly is accommodated in the inner space of the upper pouch 121 and the portions folded by the side folding portion and the upper folding portion are sealed using a sealing tool, a secondary battery having a prescribed size width is produced. .

At this time, for convenience of description, when referring to FIG. 1, the upper folding part 122b is formed in the upper pouch 121 and the lower pouch 122 in a combined state, and the bent portion S on the opposite side thereof. The direction in which the is formed is named as the downward direction.

2 is a schematic diagram illustrating a folding and sealing process of a pouch type secondary battery according to a 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 configured such that the positive electrode plate and the negative electrode plate are disposed with the separator interposed therebetween. The electrode assembly 110 is provided with an electrode tab 111. That is, the positive electrode tab may be attached to the positive electrode plate of the electrode assembly 110, and the negative electrode tab may be attached to the negative electrode plate of the electrode assembly 110.

The positive electrode tab and the negative electrode tab may protrude out of the pouch 120 to form a positive electrode terminal and a negative electrode terminal. In this case, the positive electrode tab and the negative electrode tab may not be directly exposed to the outside of the pouch 120, but may be connected to other components such as the positive electrode lead and the negative electrode lead, and the positive electrode lead and the negative electrode lead may be exposed to the outside of the pouch 120. .

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

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

The primary folding step includes a primary side folding step and an upper folding step, as shown in FIG.

In the first side folding step, side folding parts 122a provided at both sides of the lower pouch 122 are bent by 180 ° to surround the side surface of the upper pouch 121. Accordingly, the metal layer that has been exposed at both ends of the upper pouch 121 is stably covered by the side folding part 122a of the lower pouch 122 so that the metal layer is not exposed to the outside.

In the upper folding step, the upper folding part 122b provided on the upper portion of the lower pouch 122 is bent 180 ° toward the inner space to cover a portion of the upper side of the upper pouch 121. The upper folding part 122b may be alternately disposed so as not to interfere with the electrode tab 111 of the electrode assembly 110.

The sealing step is a step of sealing the primary folded side folding part 122a and the upper folding part 122b by heat fusion or the like to seal the inner space of the pouch as shown in FIG. In addition, the upper contact portion between the upper pouch 121 and the lower pouch 122 may be insulated and sealed using an insulating tape T such as a terrace tape.

In the second folding step, as shown in FIG. 2C, the side folding part 122a of the lower pouch 122 that is primarily folded is bent again. The final size and shape of the secondary battery may be determined by folding in the secondary folding step.

When the secondary folding step is performed, the side edge end portion of the lower pouch 122 is bent toward the inner space side. Accordingly, the side metal layer of the lower pouch 122 that is exposed to the outside is also hidden. Therefore, the insulation state of the side metal layer of the lower pouch 122 may be secured.

As described above, according to the exemplary embodiment of the present invention, the insulation or airtightness of both sides of the pouch 120 may be completed through one sealing operation performed between the primary folding and the secondary folding.

That is, as in the embodiment of the present invention, when manufacturing the secondary battery using the upper pouch 121 and the lower pouch 122 having different widths, the first folding-sealing-second folding of the pouch-type secondary battery As the manufacturing process proceeds, insulation work using insulation 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 is the same, the manufacturing process of the secondary battery proceeds in the order of sealing-primary side folding-side insulation by Kapton tape, in this case incidental such as Kapton tape Configuration is required, which can increase manufacturing costs.

3 illustrates a secondary battery pouch according to a second embodiment of the present invention. In the second embodiment, the same reference numerals are assigned to the same components as those in the first embodiment.

Referring to FIG. 3, the secondary battery pouch 130 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.

At least one of the upper pouch 131 and the lower pouch 132 is formed an inner space 131a for accommodating the electrode assembly 110 (refer to FIG. 4), and the electrode assembly and the electrolyte are accommodated in the inner space 131a. do.

Side folding portions 132a extend in the lateral direction on both sides of the lower pouch 132, and lower folding portions 132c extend in the lower direction under the lower pouch 132. That is, the width of the lower pouch 132 is formed wider than the width of the upper pouch 131, the length of the lower pouch 132 is formed longer than the length of the upper pouch 131.

The upper folding part 132b is formed on the lower pouch 132. The upper folding part 132b may be disposed 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 a second embodiment of the present invention.

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

That is, when the electrode assembly 110 is accommodated in the pouch 130, and the upper pouch 131 is disposed corresponding to the upper side of the lower pouch 132, the pouch 130 may be a primary folding step, a sealing step, and a secondary. By going through the folding step, the secondary battery manufacturing process proceeds.

The primary folding step includes a primary side folding step, an upper folding step and a primary lower folding step, as shown in FIG.

In the first side folding step, side folding parts 132a provided on both sides of the lower pouch 132 are bent by 180 ° to surround the side surface of the upper pouch 131. Accordingly, the metal layers exposed to both ends of the upper pouch 131 are covered by the side folding parts 132a of the lower pouch 132 so that they are not exposed to the outside.

In the upper folding step, the upper folding part 132b provided on the upper portion of the lower pouch 132 is bent 180 ° toward the inner space to cover a portion of the upper side of the upper pouch 131.

In the first lower folding step, the lower folding part 132c provided on the lower side of the lower pouch 132 is bent by 180 ° to surround the lower side of the upper pouch 131. Accordingly, the metal layer exposed to the lower end of the upper pouch 131 is covered by the lower folding part 132c of the lower pouch 132 so that the metal layer is not exposed to the outside.

The sealing step is a step of sealing the primary folded side folding portion 132a, the upper folding portion 132b and the lower folding portion 132c by heat fusion, as shown in FIG. 4 (b). In addition, the upper contact portion between the upper pouch 131 and the lower pouch 132 may be insulated and sealed using an insulating tape T such as a terrace tape.

In the second folding step, as shown in FIG. 4C, the side folding part 132a and the lower folding part 132c of the first lower folded pouch 132 are bent again. The final size and shape of the secondary battery may be determined by folding in the secondary folding step.

When the secondary folding step is performed, the side edges and the lower edges of the lower pouch 132 are bent toward the inner space. Accordingly, the metal layers on the side and bottom sides of the lower pouch 132 that were exposed to the outside are also hidden. Therefore, the insulation state of the metal layers on the side and bottom sides of the lower pouch 132 can be secured.

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

In addition, the pouch type secondary battery according to an embodiment of the present invention may be applied to a device including the secondary battery as a power source.

For example, the device may be a computer, mobile phone, wearable electronics, power tool, electric vehicle (EV), hybrid electric vehicle, plug-in hybrid electric vehicle, electric motorcycle, electric golf cart, or electric power. It may be a storage device. The power storage device may be applied to various fields and places, such as a smart grid system for controlling power supply and demand or a charging station of an electric vehicle.

As those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features, the embodiments described above should be understood as illustrative and not restrictive in all respects. Should be.

The scope of the present invention is shown by the appended claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. .

100; Secondary battery 110; Electrode Assembly
111; Electrode tab
120, 130; Pouches 121, 131; Upper Pouch
121a, 131a; Internal spaces 122 and 132; Bottom pouch
122a, 132a; Side folding portions 122b and 132b; Upper folding part
132c; Lower folding portion 123; Bend

Claims (8)

In the pouch for a secondary battery,
Lower pouch;
And an upper pouch disposed above the lower pouch.
Secondary battery pouches on both sides of the lower pouch extending side-folding formed wider than the width of the upper pouch.
The method of claim 1,
And an upper folding part provided on an upper portion of the lower pouch, wherein the upper folding part is bent to surround an upper side of the upper pouch.
The method of claim 1,
The upper pouch and the lower pouch are integrally formed, and a secondary battery pouch having a bent portion formed at a boundary portion between the upper pouch and the lower pouch.
The method of claim 1,
The upper pouch and the lower pouch are formed in a separate type, the lower folding portion is formed to extend below the lower pouch, the lower folding portion is bent to surround the lower portion of the upper pouch pouch.
In the pouch type secondary battery,
Electrode assembly;
And a lower pouch and an upper pouch disposed above the lower pouch.
A pouch type secondary battery having side folding portions formed on both sides of the lower pouch to be wider than the width of the upper pouch.
The method of claim 5,
A pouch type secondary battery further includes an upper folding part provided on an upper portion of the lower pouch, wherein the upper folding part is bent to surround an upper side of the upper pouch.
The method of claim 6,
The secondary battery includes an electrode tab exposed to the outside of the pouch, the upper folding portion is a pouch type secondary battery disposed so as not to interfere with the electrode of the secondary battery.
A battery pack comprising two or more pouch type secondary batteries according to any one of claims 5 to 7.

Images