KR20160041402A - Pouch type secondary battery and a method of making the same - Google Patents

Abstract

The present invention relates to a pouch-type rechargeable battery, comprising: an electrode assembly; an electrode lead coupled to the electrode assembly; and a pouch enclosure including an upper pouch having a panel-shaped central area, a lower pouch having a space in a central area to accommodate the electrode assembly, and a sealing unit provided at edges of the upper and lower pouches to be sealed. The sealing unit is configured to comprise a front-surface-arranged sealing unit whose at least one side is folded to an upper portion of the upper pouch. The purpose of the present invention is to provide a pouch-type rechargeable battery with a compact shape and improved cooling efficiency.

Description

 BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a pouch type secondary battery,

The present invention relates to a pouch type secondary battery, and more particularly, to a pouch type secondary battery having a compact structure and exhibiting an improved cooling effect.

Secondary batteries having high electrical characteristics such as high energy density and high ease of application according to the product group can be applied not only to portable devices but also to electric vehicles (EVs) or hybrid electric vehicles (HEVs) driven by electric driving sources, Storage devices (Energy Storage System) and so on. Such a secondary battery is not only a primary advantage that the use of fossil fuel can be drastically reduced, but also produces no by-products resulting from the use of energy, and thus is attracting attention as a new energy source for enhancing environmental friendliness and energy efficiency.

A battery pack applied to an electric vehicle has a structure in which a plurality of cell assemblies including a plurality of unit battery cells are connected in series in order to obtain high output. The unit battery cell may include a positive electrode and a negative electrode current collector, a separator, an active material, an electrolyte, and the like, and may be repeatedly charged and discharged by electrochemical reaction between the components.

In addition to this basic structure, the battery pack has a function of controlling electric power supply to a driving load of a motor and the like, measuring electric characteristic values such as a current or a voltage, controlling charging and discharging, controlling voltage equalization, estimating state of charge (SOC) (Battery Management System) for monitoring and controlling the state of the secondary battery by applying an algorithm to the secondary battery.

Since such a middle- or large-sized battery pack is preferably compact and small in weight, a prismatic battery or a pouch-type battery having a high degree of integration and a large capacity by weight is mainly used as a unit battery cell of a middle- or large-sized battery pack. Particularly, pouch type battery cells have recently attracted a lot of attention due to their low manufacturing cost, small weight, and easy shape deformation.

On the other hand, since the middle- or large-sized battery pack is manufactured in such a manner that a plurality of cell assemblies are densely packed in a narrow space, it is very important to emit heat generated in each battery cell. If the heat of the battery cell is not effectively released, the performance may not be exhibited properly, and deterioration may be promoted, which may cause ignition or explosion. Accordingly, the related industry is focused on the development of a large-sized, large-capacity, compact structure and a large-sized battery pack with excellent cooling efficiency.

1 is a view schematically showing a part of a battery module including a conventional pouch type secondary battery.

Generally, the pouch type secondary battery is formed of a pouch outer casing that accommodates an electrode assembly and an electrode assembly (11). Here, the pouch exterior member is composed of the upper pouch and the lower pouch. The outer periphery of the upper pouch and the lower pouch are provided with sealing portions and the sealing portions are bonded to each other, thereby sealing the internal space in which the electrode assembly 11 is accommodated.

However, the sealing portion of the pouch-type secondary battery 10 constituting the cell assembly, in particular, the wing portion 12, to which the electrode lead is not exposed, is prevented from directing the product. Accordingly, in the conventional case, there is an attempt to reduce the dead space by folding the wing 12 to overlap the left side surface portion L and / or the right side surface portion of the pouch type secondary battery 10. 1, the conventional folded type wing 12 is folded so as to overlap the left side surface portion L and / or the right side surface portion of the pouch type secondary battery 10, During cooling, a temperature deviation may occur between the folded region of the wing 11 and the non-folded region. 1, when heat generated in the pouch-shaped secondary battery 10 is transferred to the cooling member 13 at a position adjacent to the left side surface portion L or the right side surface portion of the pouch type secondary battery 10, The portion where the portions of the upper surface 11 overlap is higher than the portion where the portions are not. Therefore, in the region where the wings 11 are overlapped, the heat is not properly transferred from the electrode assembly 11 toward the cooling member 13, which may cause a decrease in the overall cooling efficiency of the pouch type secondary battery 10 .

Japanese Patent Application JP 2007-220544 A Toyota Motor Corporation.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a pouch type rechargeable battery which is capable of effectively achieving a compact shape by effectively arranging a wing of a conventional pouch type secondary battery, A secondary battery, and a secondary battery.

Other objects and advantages of the present invention will become apparent from the following description, and it will be understood by those skilled in the art that the present invention is not limited thereto. It will also be readily apparent that the objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

According to the present invention, there is provided an electrode assembly comprising: an electrode assembly; An electrode lead connected to the electrode assembly; And an upper pouch having a central region in a plate-like shape and a lower pouch forming a space for accommodating the electrode assembly in a central region, and a pouch-type sheathing member having a sealing portion at an edge of the upper pouch and the lower pouch, And the sealing portion may include a top surface disposing sealing portion having at least one side thereof folded over the upper portion of the upper pouch.

The upper surface disposition sealing portion may be formed by folding the upper surface of the upper pouch with both side edge portions of the pouch exterior material from which the electrode lead is not exposed.

The upper surface disposition sealing portion may be disposed in contact with the upper surface of the upper pouch in parallel.

The upper surface disposition sealing portion may have a shape bent at least twice.

The upper surface disposition sealing portion may have a curved shape having a predetermined curvature radius on the upper surface of the upper pouch.

The top surface disposition sealing portion may be adhered to the upper surface of the upper pouch.

According to another aspect of the present invention, a battery pack including the above-described pouch-type secondary battery can be provided.

According to another aspect of the present invention, there is provided a method of manufacturing an electrode assembly, the method comprising: preparing a lower pouch having a storage space for an electrode assembly; Storing the electrode assembly in an accommodating space of the lower pouch so that an electrode lead is exposed to the outside; Sealing the lower pouch and the sealing portion formed at the edge of the upper pouch; And folding at least one of the sealing portions to the upper portion of the upper pouch.

The folding step may include bending at least one side of the sealing part at least twice.

The folding step may include placing at least one side of the sealing parts in contact with the upper surface of the upper pouch in parallel.

The folding step may include bonding at least one side of the sealing portion to the upper surface of the upper pouch.

According to an aspect of the present invention, it is possible to provide a pouch-type secondary battery in which the temperature deviation is small in the indirect cooling method and the heat conduction to the outside smoothly improves the cooling efficiency.

According to another aspect of the present invention, it is possible to provide a pouch-type secondary battery having a compact shape by effectively arranging a wing portion formed in a conventional pouch-type secondary battery.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a view schematically showing a part of a battery module including a conventional pouch type secondary battery. FIG.
2 is a perspective view of a pouch type secondary battery according to an embodiment of the present invention.
FIG. 3 is a view of FIG. 2 as viewed from below.
4 is a schematic cross-sectional view according to AA of Fig.
5 is a schematic view showing a part of a secondary battery module including a pouch type secondary battery according to an embodiment of the present invention.
6 is a cross-sectional view taken along line BB in Fig.
FIG. 7 is a schematic view illustrating a manufacturing process of a pouch type secondary battery according to an embodiment of the present invention. Referring to FIG.

The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms and the inventor may appropriately define the concept of the term in order to best describe its invention It should be construed as meaning and concept consistent with the technical idea of the present invention.

Therefore, the embodiments described in the present specification and the configurations shown in the drawings are only the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. Therefore, It is to be understood that equivalents and modifications are possible.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Like reference symbols in the drawings denote like elements.

FIG. 2 is a perspective view of a pouch type secondary battery according to an embodiment of the present invention. FIG. 3 is a plan view of FIG. 2, and FIG. 4 is a schematic cross-sectional view of FIG.

As shown in these drawings, the pouch type secondary battery according to the present invention includes an electrode assembly (110, see Fig. 7), an electrode lead 120, and a pouch exterior member.

Here, the pouch exterior member includes an upper pouch 131 having a central region in a plate shape, and a lower pouch 132 forming a space for accommodating the electrode assembly 110 in a central region. The upper pouch 131 and the lower pouch 131 132 at the edges thereof. The sealing portion S may have a folded shape such that at least one side thereof is bent or bent to be disposed above the upper pouch 131, that is, above the upper surface U of the upper pouch 131.

The electrode assembly 110 (see Fig. 7) includes a positive electrode plate, a negative electrode plate, a separator, and an electrode tab, although not shown in detail for the sake of convenience of illustration. The electrode assembly 110 may be of a laminate type formed by interposing a separator between the stacked positive and negative electrode plates, or a jelly-roll type in which one positive electrode plate and one negative electrode plate are wound with a separator interposed therebetween. Of course, the scope of the present invention is not limited to this type of electrode assembly 110. The positive electrode plate may be formed by applying a positive electrode active material to a collector plate made of aluminum (Al), and the negative electrode plate may be formed by applying a negative electrode active material to a collector plate made of copper (Cu). The electrode tab includes a positive electrode tab corresponding to a region of the positive electrode plate not coated with the positive electrode active material and a negative electrode tab corresponding to a region of the negative electrode plate not coated with the negative electrode active material.

 The electrode lead 120 is attached to the electrode tab as a thin plate-like metal and extends in the outer direction of the electrode assembly 110. The electrode lead 120 includes a positive electrode lead 121 attached to the positive electrode tab and a negative electrode lead 122 attached to the negative electrode tab.

The positive electrode lead 121 and the negative electrode lead 122 may extend in different directions or may extend in the same direction (see FIG. 2) depending on the positions of the positive electrode tab and the negative electrode tab.

The pouch exterior member 130 houses the electrode assembly 110 and the electrolyte in the internal space. In particular, the pouch exterior member 130 may include an outer insulating layer made of a polymer material, an inner adhesive layer, and a metal layer interposed between the outer insulating layer and the inner adhesive layer. Here, aluminum (Al) may be used as a material of the metal layer.

The pouch case 130 protects the internal components such as the electrode assembly 110 and the electrolyte and performs the function of complementing and dissipating the electrochemical properties of the electrode assembly 110 and the electrolyte.

2 to 4, the pouch exterior member 130 according to the present embodiment may include an upper pouch 131 and a lower pouch 132 bonded to the upper pouch 131.

The upper pouch 131 is formed in a plate-like shape as a whole and the lower pouch 132 is formed with a concave central region so that the electrode assembly 110 can be housed therein. Here, the concave space of the lower pouch 132 may be formed to correspond to the height and width of the electrode assembly 110. A sealing portion S which is thermally fused and sealed with each other is positioned at the edges of the upper pouch 131 and the lower pouch 132.

Hereinafter, the sealing portion S of the pouch exterior member 130 will be described in detail. Prior to explanation, the criteria for the directionality of the pouch type secondary battery 100 according to the present embodiment will be defined. 2, a portion (side) to which the electrode lead 120 is exposed is referred to as a front side portion F and a front side portion F of the pouch type secondary battery 100, and a left side portion and a right side portion A left side portion L and a right side portion R of the pouch type secondary battery 100 and a portion located on the opposite side to the front portion F are defined as a rear portion RE of the pouch type secondary battery 100 . The outer surface U of the upper pouch 131 is connected to the upper surface U of the pouch type secondary battery 100 and the outer surface of the lower pouch 132 parallel to the upper pouch 131, (D).

Of course, in the present embodiment, terms indicating directions such as front, back, left, right, top, and bottom are used, but these terms are for convenience of explanation only and vary depending on the position of the object or the position of the observer .

2 and 3, the sealing portion S according to the present embodiment includes a front sealing portion S1 located on the front portion F of the pouch type secondary battery 100, S1 disposed on the rear surface RE of the pouch type rechargeable battery 100 and positioned on the outer surface U of the upper pouch 131 and the rear surface sealing portion S2 located on the rear surface RE of the pouch type rechargeable battery 100, S3.

More specifically, the front sealing portion S1 is a portion extending outward from the front portion F of the pouch type secondary battery 100, and the electrode lead 120 may be exposed to the outside have.

The rear sealing portion S3 is a portion extending outward from the rear portion RE of the pouch type secondary battery 100. [ The rear sealing portion S3 is located on the opposite side of the front sealing portion S1 on the same plane. However, unlike the present embodiment, the rear sealing part S3 may be bent and disposed in parallel with the outer surface U of the upper pouch 131, as in the case of the upper surface sealing part S2 described later.

The upper surface disposition sealing portion S2 according to the present embodiment is disposed in parallel to the upper surface U of the pouch type secondary battery 100, that is, the outer surface U of the upper pouch 131. Particularly, in the upper surface arrangement sealing portion S2, the front sealing portion S1 and the rear sealing portion S3 extend outward from the front portion F and the rear portion RE of the secondary battery 100, respectively The left side surface portion L and the right side surface portion R of the secondary battery 100 are bent at least 90 degrees. Therefore, as shown in FIG. 3, the pouch type secondary battery 100 of the present invention has a wing portion of the conventional pouch type secondary battery as described above, It can be done.

In other words, in the present embodiment, the upper pouch 131 and the lower pouch 132 have four corners along the circumferential direction. The edge of the lower pouch 132 is thermally fused with the edge of the upper pouch 131 in a plate-like shape to form a sealing portion S for sealing the pouch exterior member 130. Therefore, the sealing portion S immediately after the sealing can be removed from the central region of the pouch exterior member in which the electrode assembly 110 is housed, that is, the front portion F, the rear portion RE, The left side surface portion L and the right side surface portion R are outwardly sloped. As described above, the sealing portions S that are outwardly protruded from the left side surface portion L and the right side surface portion R of the secondary battery have a dead space, which is an unnecessary space in the pouch type secondary battery 100, . Further, in this case, as described above, it is structurally undesirable in terms of heat transfer. However, after the upper pouch 131 and the lower pouch 132 are thermally fused, the pouch-shaped secondary battery 100 of the present invention is configured such that the upper-surface disposition sealing portion S2 is disposed on the left side portion L of the pouch- And the right side surface portion R so that the upper surface side sealing portion S2 is folded side by side on the outer surface of the upper pouch 131.

Meanwhile, the top surface sealing part S2 according to the present invention may have a shape bent at least twice. 4, the upper surface disposition sealing portion S2 may be arranged in parallel with the outer surface U of the upper pouch 131 by being folded again by 180 degrees in a state where the upper surface disposition sealing portion S2 is folded in a half first.

Generally, when the sealing force of the sealing part of the prior art is weakened, a gap may be formed in the sealing part, so that the electrolytic solution may flow into the gap or the permeation rate of moisture from the outside into the inside of the pouch case 130 may be increased. However, the upper surface disposition sealing portion S2 according to the present embodiment is advantageous in that the path is more complicated and the end portion is not exposed to the outside, thereby lowering the leakage of the electrolytic solution and the permeability of moisture to the outside.

However, the scope of the present invention is not limited to these embodiments. That is, the top-surface-arranging sealing portion S2 may have a bent shape once or three or more times, or may have a bent shape having a predetermined curvature. In other words, the upper surface disposition sealing portion having a curved shape may have a lower water permeation blocking efficiency than the upper surface disposition sealing portion S2 having the above-mentioned two-fold folded shape, but may be advantageous in that the processing process is simplified.

The top surface positioning sealing portion S2 according to the present embodiment is formed by an adhesive member such as a sealant so as not to be separated from the outer surface U of the upper pouch 131 by an external force, As shown in Fig. The upper surface disposition sealing portion S2 may be advantageous in that it can be readily attached to a cartridge or a frame frame customized to the shape of the pouch type secondary battery 100 of the present invention.

The pouch type secondary battery 100 of the present invention may have a compact structure than the conventional one and the size of the battery module including a plurality of the pouch type secondary batteries 100 may be compact, Can be done.

In addition, the pouch type secondary battery 100 according to the present invention can have a better cooling efficiency than the conventional one. Hereinafter, a brief description will be made with reference to FIG. 5 and FIG.

One or more of the pouch type secondary batteries 100 according to the present invention may be accommodated in the cartridge 200. [ Although not shown in detail for the sake of convenience, the cartridge 200 may be configured to allow the pouch type secondary battery 100 to be seated, hold it, prevent the flow thereof, and stack the batteries.

The pouch type secondary battery 100 may be provided adjacent to the left side L and / or the right side R thereof with a cooling member 300 capable of exchanging heat with the pouch type secondary battery 100. As the cooling member 300, a cooling fin, a heat sink, and / or a cooling channel for transferring the heat of the secondary battery 100 may be applied. The cooling channel may be a duct forming a flow path of cooling air or cooling water.

5 and 6, by cooling the cooling fins in contact with the cartridge 200 through the coolant, the heat generated in the pouch type secondary battery 100 is transmitted through the cooling fins, and the cooling fins again transmit heat to the coolant . Here, the cooling fin may be formed with a heat sink for rapid heat exchange with the refrigerant.

Particularly, in the indirect cooling method as in the present embodiment, the heat inside the pouch-shaped battery cell exits through the left side surface portion L and / or the right side surface portion R of the pouch type secondary battery 100. In this case, since the sealing portion of the left side surface portion L and / or the right side surface portion R does not exist in the path where the heat escapes from the electrode assembly 110 to the cooling member, So that the heat transfer to the outside can be more effectively achieved than in the prior art.

FIG. 7 is a schematic view illustrating a manufacturing process of a pouch type secondary battery according to an embodiment of the present invention. Referring to FIG.

Hereinafter, a method of manufacturing the pouch type secondary battery of the present invention will be described with reference to FIG.

A method of manufacturing a pouch type secondary battery 100 according to the present invention includes a lower pouch 132 and a plate-shaped upper pouch 132 in which a lower pouch 132 and an edge region are thermally fused to form a storage space for the electrode assembly 110 The electrode assembly 110 is exposed to the outside and the electrode assembly 110 is inserted into the lower pouch 132 and the edge of the upper pouch 131 so as to be accommodated therein, And a folding step of folding at least one of the sealing portions S to the upper surface U of the upper pouch 131, .

In the present embodiment, the sealing step is performed in such a manner that four corners of the upper pouch 131 and the lower pouch 132 having a rectangular-shaped rim are aligned, and then these are adhered to each other. At this time, the sealing portion S has a thermal adhesive layer on the inner circumferential surface of the sealing portion S and can be bonded by heat and pressure.

The folding step includes bending at least one side of the sealing portion (S) at least twice. In the present embodiment, the sealing portion S includes the front sealing portion S1, the rear sealing portion S3, and the top surface positioning sealing portion S2 as described above. When the sealing step S is completed, the top surface positioning sealing portion S2 ) Is subjected to folding. First, as shown in Fig. 7 (b), the upper surface disposition sealing portion S2 is folded 180 degrees along the imaginary line L1. Then, as shown in FIG. 7 (c), the top surface disposition sealing portion S2 is folded 180 degrees along the imaginary line L2 by 180 degrees so that the entire upper surface disposition sealing portion S2 is folded over the upper pouch 131, So that it can be positioned side by side on the outer side U of the frame. The main purpose of performing the folding step is to prevent the upper surface arrangement sealing portion S2 from protruding from the left side surface portion L and / or the right side surface portion R of the pouch type secondary battery 100, It is not limited to the same manner as the example, and is not necessarily folded. Also, the upper surface arrangement sealing portion S2 may be bent or bent to the outer side surface U of the upper pouch 131 with a predetermined radius of curvature.

The method for manufacturing the pouch type secondary battery 100 according to the present invention is a method for manufacturing the pouch type secondary battery 100 according to the present invention so as to prevent the upper surface arrangement sealing portion S2 from hitting the outer surface U of the upper pouch 131, (U) with an adhesive such as a sealant.

Meanwhile, the battery pack according to the present invention may include two or more pouch type secondary batteries 100 according to the present invention. In particular, the battery pack according to the present invention may include at least one battery module according to the present invention. In addition to the battery module, the battery pack may further include a case for covering the battery module, and various devices for controlling charge and discharge of the battery module, such as a BMS, a current sensor, a fuse, and the like.

For example, the pouch type secondary battery 100 according to the present invention, particularly the battery module according to the present invention, can be applied to automobiles and IT product groups such as electric vehicles and hybrid vehicles.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Accordingly, such modifications or variations are intended to fall within the scope of the appended claims.

100: Pouch type secondary battery
110: electrode assembly
120: electrode lead
130: Pouch Exterior Material
131: upper pouch
132: Lower pouch
S: sealing part
S1: Front sealing part
S2: upper surface positioning sealing portion

Claims (11)

An electrode assembly;
An electrode lead connected to the electrode assembly; And
And a pouch outer case having a sealing pouch at an edge of the upper pouch and the lower pouch, wherein the upper pouch has a plate-shaped upper pouch and a lower pouch for forming a space for accommodating the electrode assembly in a central area,
The sealing portion
Wherein at least one side of the upper pouch is provided with a top surface disposing sealing part folded on the upper side of the upper pouch. The method according to claim 1,
The upper surface-
Wherein both side edge portions of the pouch exterior member, from which the electrode leads are not exposed, of the sealing portions are folded to the upper portion of the upper pouch. 3. The method of claim 2,
The upper surface-
Wherein the upper and lower pouches are disposed in parallel with each other on the upper surface of the upper pouch. The method of claim 3,
The upper surface-
Wherein the pouch type secondary battery has a shape bent at least twice. The method of claim 3,
The upper surface-
And a curved shape having a predetermined curvature radius on an upper surface of the upper pouch. 3. The method of claim 2,
The upper surface-
Wherein the upper and lower pouches are bonded to the upper surface of the upper pouch. A battery pack comprising the pouch type secondary battery according to any one of claims 1 to 6. Preparing a lower pouch having a storage space for the electrode assembly and a plate-shaped upper pouch;
Storing the electrode assembly in an accommodating space of the lower pouch so that an electrode lead is exposed to the outside;
Sealing the lower pouch and the sealing portion formed at the edge of the upper pouch; And
And folding at least one of the sealing portions to an upper portion of the upper pouch. 9. The method of claim 8,
Wherein the folding step comprises bending at least one side of the sealing part at least twice. 9. The method of claim 8,
Wherein the folding step comprises placing at least one side of the sealing parts in contact with the upper surface of the upper pouch in parallel. 11. The method of claim 10,
Wherein the folding step comprises bonding at least one side of the sealing portion to the upper surface of the upper pouch.

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