KR20140039349A - Secondary battery of improved cooling efficiency - Google Patents

Abstract

The present invention provides a secondary battery comprising: a first electrode assembly and a second electrode assembly for a structure which includes an anode, a cathode, and a separator interposed therebetween; a battery case of a structure which is made of a laminate sheet where a first housing part and a second housing part are formed to house the first and second electrode assemblies respectively, and the portion between the first and second housing parts are bent to be folded such that the first and second housing parts are vertically stacked; and a cooling member mounted to contact an outer surface of the bent portion between the first and the second housing parts of the battery case.

Description

Secondary Battery Of Improved Cooling Efficiency

The present invention relates to a secondary battery having improved cooling efficiency, and more particularly, a first electrode assembly and a second electrode assembly having a structure in which a separator is interposed between a positive electrode, a negative electrode, and a positive electrode and a negative electrode, and the first electrode assembly. And a laminate sheet on which a first accommodating part and a second accommodating part each accommodate the second electrode assembly are formed. The laminate sheet is bent between the first accommodating part and the second accommodating part so that the first accommodating part and the second accommodating part are up and down. A secondary battery comprising: a battery case having a structure folded to be stacked, and a cooling member mounted in contact with an outer surface of a bent portion between the first and second accommodating portions of the battery case. It is about.

BACKGROUND ART [0002] In recent years, rechargeable secondary batteries have been widely used as energy sources for wireless mobile devices. In addition, the secondary battery is an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (HEV), and the like, which are proposed as solutions for air pollution of existing gasoline vehicles and diesel vehicles using fossil fuels (Plug-In HEV) and the like.

In a small mobile device, one or two or more battery cells are used per device, while a middle- or large-sized battery module such as an automobile is used as a middle- or large-sized battery module in which a plurality of battery cells are electrically connected due to the necessity of a large-

Since the middle- or large-sized battery module is preferably manufactured in a small size and weight, a prismatic battery, a pouch-shaped battery, or the like, which can be charged with a high degree of integration and has a small weight to capacity, is mainly used as a battery cell have. In particular, a pouch-shaped battery using an aluminum laminate sheet or the like as an exterior member has recently attracted a lot of attention due to its advantages such as small weight, low manufacturing cost, and easy shape deformation.

Since the battery cells constituting the medium-large battery module are composed of secondary batteries capable of charging and discharging, such a high output large capacity secondary battery generates a large amount of heat during the charging and discharging process.

If the heat of the battery module generated during the charging and discharging process can not be effectively removed, heat accumulation may occur, thereby accelerating the deterioration of the battery module and possibly causing ignition or explosion. Therefore, a high output large capacity battery module needs a cooling system for cooling the battery cells embedded therein.

The battery module is generally manufactured by stacking a plurality of battery cells with high density, and stacks adjacent battery cells at regular intervals so as to remove heat generated during charging and discharging. For example, the battery cells themselves may be sequentially stacked while being spaced apart from each other by a predetermined space, or in the case of a battery cell having low mechanical rigidity, one or a combination of two or more batteries may be built in a cartridge or the like. The battery module can be configured. The stacked battery cells or the battery modules are structured such that a flow path of the coolant is formed between the battery cells or the battery modules so as to effectively remove accumulated heat.

However, this structure has a problem that the total size of the battery module is increased because a plurality of refrigerant flow paths must be secured corresponding to a plurality of battery cells.

In addition, as the stacking of many battery cells increases the volume of the battery module due to the addition of a large number of components in relation to the cooling structure, the manufacturing process is complicated, resulting in a significant increase in the manufacturing cost.

Accordingly, there is a need for a secondary battery having excellent life characteristics and safety due to high cooling efficiency while being able to be manufactured in a simple and compact structure while providing high output large capacity power.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-described problems of the prior art and the technical problems required from the past.

Specifically, an object of the present invention is to provide a secondary battery that can improve the cooling efficiency of the secondary battery, reduce the number of parts required for the cooling structure and simplify the structure to reduce the manufacturing cost.

Still another object of the present invention is to provide a secondary battery having excellent structural stability against external shock such as vibration or dropping.

According to an aspect of the present invention, there is provided a secondary battery comprising:

A first electrode assembly and a second electrode assembly having a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode;

The laminate includes a laminate sheet having a first accommodating portion and a second accommodating portion for accommodating the first electrode assembly and the second electrode assembly, respectively, wherein the first accommodating portion and the second accommodating portion are bent to form a first accommodating portion and a second accommodating portion. A battery case having a structure in which two accommodating parts are stacked up and down; And

A cooling member mounted in contact with an outer surface of the bent portion between the first accommodating part and the second accommodating part of the battery case;

As shown in FIG.

That is, the cooling member is brought into contact with the bent portion between the first accommodating portion and the second accommodating portion of the battery case to perform cooling, thereby directly transferring heat generated from the battery to the cooling member without a separate component. Therefore, the cooling structure of the secondary battery according to the present invention provides an effect of reducing the manufacturing cost by reducing the number of parts and simplifying the structure compared with the cooling structure of the conventional secondary battery.

In one specific example, the battery case,

A lower case in which the first accommodating part and the second accommodating part are formed; And

An upper case covering an upper surface of a lower case in a state in which a first electrode assembly and a second electrode assembly are respectively accommodated in the first accommodating portion and the second accommodating portion;

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The outer circumferential surfaces of the lower case and the upper case and between the first accommodating part and the second accommodating part may be heat-sealed and sealed.

The secondary battery included in the conventional battery pack or the battery module is configured in a structure in which the electrode assembly is accommodated in the battery case formed with one housing, the electrode lead connected to the electrode assembly protrudes out of the battery case to form the electrode terminal. .

However, the secondary battery according to the present invention has a structure that ensures structural stability against external shocks such as vibration or drop by forming a plurality of accommodating parts in the battery case in which the electrode assembly is independently received.

In one specific example, each of the upper case and the lower case may be formed of a member of one unit. That is, the battery case may be formed in a structure including a lower case made of one unit member having a first accommodating part and a second accommodating part, and an upper case made of one unit member covering an upper surface of the lower case. . This structure, compared with the secondary battery of the structure that connects two battery cells having one housing, not only can ensure the durability of the connection portion between the housing, but also reduce the number of parts, manufacturing processability To improve the effect.

An inner frame may be further included between the first accommodating part and the second accommodating part to support the stacked structure of the accommodating parts. The inner frame may be formed to have a structure surrounding the outer circumferential surfaces of the first accommodating part and the second accommodating part in a folded state of the battery case such that the first accommodating part and the second accommodating part are stacked above and below the inner frame.

The bent portion between the first accommodating part and the second accommodating part of the battery case may be formed in various shapes. For example, a portion between the first accommodating part and the second accommodating part of the battery case is formed on a vertical cross section. The battery case may have a structure in which the first accommodating part and the second accommodating part are folded to be stacked up and down so as to form a “c” shape. At this time, the cooling member may be in contact with the surface of the portion protruding outward from the "c" shape.

A battery module or a battery pack having a structure in which a plurality of secondary batteries are connected is a unit cell of a secondary battery including a rectangular plate-shaped electrode assembly, in order to facilitate stacking of secondary batteries and to form a compact size when stacked. It is preferable to include as.

Therefore, the first electrode assembly and the second electrode assembly may be formed in a rectangular plate-like structure, and the accommodating parts accommodating the electrode assembly may also be formed in a rectangular structure.

The rectangular accommodating parts may be formed at various positions on the battery case. For example, the accommodating parts may be formed on the battery case such that the long sides of the first accommodating part and the long sides of the second accommodating part are parallel to each other. The first accommodating part and the second accommodating part may be formed.

In one specific example, the electrode assembly has a positive terminal is formed on one side and the negative terminal is formed on the opposite side, the positive terminal and the negative terminal is to be formed in a structure protruding outside the sealed portion of the battery case Can be.

At this time, the positive electrode terminal of the first electrode assembly and the negative electrode terminal of the second electrode assembly protrude from one side of the outer circumferential surface of the battery case, and the negative terminal of the first electrode assembly and the positive electrode terminal of the second electrode assembly are opposite to each other. It may be a structure that protrudes. That is, the positive terminal and the negative terminal may be formed to protrude one by one in the same direction.

In this structure, in a state where the first accommodating part and the second accommodating part are folded up and down, the positive electrode terminal of the first electrode assembly and the negative electrode terminal of the second electrode assembly may be electrically connected. In detail, the portion between the first accommodating part and the second accommodating part may be bent so that each accommodating part may be overlapped vertically, and then the positive terminal and the negative terminal may be connected in series.

The material is not particularly limited as long as the cooling member is a member having thermal conductivity. For example, a metal material may be preferably used. The metal material may be aluminum or aluminum alloy having high thermal conductivity and light weight among metals, but is not limited thereto.

In addition, the cooling member may be an air-cooled member or a water-cooled member, and may have a structure in which a contact surface with external air is maximized or a coolant flow path through which cooling water flows.

The cooling member is not particularly limited as long as it is a structure for cooling the secondary battery. For example, one side portion contacts the outer surface of the first accommodating part or the second accommodating part, and the other part is the first accommodating part and the second accommodating part. A structure including a cooling fin that is bent to be in close contact with the outer surface of the bent portion between the second accommodating portion, and a heat dissipation portion which is in contact with the outer surface of the bent portion of the cooling fin and cools the heat conducted from the cooling fin. It may be made of.

That is, the cooling member not only includes a heat dissipation unit in which an air-cooled or water-cooled structure is formed, and further includes cooling fins in contact with the accommodating part of the secondary battery. By forming the structure in contact, the cooling efficiency can be further improved. At this time, the cooling fin is preferably formed of a sheet of metal material having a thin thickness and excellent thermal conductivity.

The secondary battery is not particularly limited as long as the battery can provide a high voltage and a high current when the battery module and the battery pack are configured. For example, the secondary battery may be a lithium secondary battery having a large amount of energy storage per volume.

The present invention also provides a battery pack including the secondary battery as a unit module.

The battery pack may be manufactured by assembling the secondary battery as a unit module according to a desired output and capacity. In consideration of mounting efficiency, structural stability, and the like, an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, A storage device, etc., but the scope of application is not limited thereto.

Accordingly, the present invention provides a device including the battery pack as a power source, and the device may specifically be an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, or a power storage device.

The structure and manufacturing method of such a device are well known in the art, so a detailed description thereof will be omitted herein.

As described above, the secondary battery according to the present invention performs cooling by contacting a cooling member to a bent portion between the first and second accommodating portions of the battery case, thereby cooling the heat of the battery without a separate component. It is made of a direct delivery structure to the structure, compared to the conventional cooling structure of the secondary battery has the effect of reducing the number of parts and simplify the structure to reduce the manufacturing cost.

In addition, when manufacturing a battery module or a battery pack including a secondary battery according to the present invention, there is an effect that provides a superior structural stability compared to the conventional structure in which a secondary battery containing one electrode assembly is stacked.

1 is a schematic diagram of an exemplary pouch type secondary battery;
2 is a schematic diagram of a secondary battery according to an embodiment of the present invention;
3 and 4 are schematic views illustrating a process of manufacturing the secondary battery of FIG. 2;
FIG. 5 is a schematic diagram illustrating an inner frame included in FIG. 1; FIG.
FIG. 6 is a schematic diagram illustrating a structure in which secondary batteries of FIG. 1 are stacked and connected; FIG.
FIG. 7 is a front schematic view showing a structure in which a cooling member is added to FIG. 6; FIG.
FIG. 8 is a front schematic view illustrating a structure in which a cooling member including a cooling fin and a heat dissipation unit is added to FIG. 6.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, but the present invention is not limited by the scope of the present invention.

1 is a schematic diagram of one exemplary pouch type secondary battery.

Referring to FIG. 1, the pouch type secondary battery 10 has a structure in which two electrode leads 11 and 12 protrude from each other to protrude from an upper end portion and a lower end portion of the battery main body 13. The battery case 14 is composed of two upper and lower units and has opposite side surfaces 14b and upper and lower end portions 14a and 14b which are mutually contacted with each other with an electrode assembly (not shown) mounted on a receiving portion formed on the inner surface thereof. 14c are attached to the battery cell 10 to make the battery cell 10. The battery case 14 is made of a laminate structure of a resin layer / metal foil layer / resin layer so that heat and pressure are applied to both side surfaces 14b and upper and lower ends 14a and 14c which are in contact with each other, In some cases, it may be attached using an adhesive.

FIG. 2 is a schematic diagram of a secondary battery according to an exemplary embodiment of the present invention, and FIGS. 3 and 4 are schematic diagrams illustrating a process of manufacturing the secondary battery of FIG. 2. .

Referring to these drawings, the secondary battery 100 includes a battery case 110 in which a first accommodating part 112 and a second accommodating part 114 are formed, and a first accommodating part 112 and a second accommodating part 114. ) Is configured to include an electrode assembly (not shown) accommodated in each. In addition, an internal frame 130 is interposed between the first accommodating part 112 and the second accommodating part 114.

The battery case 110 is bent and folded between the first accommodating part 112 and the second accommodating part 114 such that the first accommodating part 112 and the second accommodating part 114 are stacked up and down.

In a state in which the first accommodating part 112 and the second accommodating part 114 of the battery case 110 are folded up and down, the negative electrode terminal 126 of the first electrode assembly and the positive electrode terminal 124 of the second electrode assembly. ) Is electrically connected. That is, the portion 118 between the first accommodating part 112 and the second accommodating part 114 is bent so that the respective accommodating parts 112 and 114 overlap vertically, and then the positive terminal 124 and the negative electrode The structure in which the terminals 126 are connected in series is shown.

The bent portion 118 between the first accommodating part 112 and the second accommodating part 112 of the battery case 110 may include the first accommodating part 112 and the second accommodating part 112 of the battery case 110. The first accommodating part 112 and the second accommodating part 112 are formed to be folded up and down so as to form a "c" shape on a vertical cross section. A cooling member (not shown) contacts the surface 119 of the portion “119” protruding outwardly to cool the battery, and the structure in which the cooling member contacts is illustrated in FIG. 7.

The first accommodating part 112 and the second accommodating part 114 are spaced apart from each other on the battery case 110, and the outer circumferential surface of the first accommodating part 112 and the outer circumferential surface of the second accommodating part 114 are each heat-sealed. And sealed, and have independent structures from each other.

In addition, the battery case 110 is composed of an upper case and a lower case each made of a member of one unit, and after receiving the electrode assembly in the storage unit formed in the upper case and / or lower case, and seals the outer peripheral surface of the storage unit It consists of a structure. However, the structure in which the accommodating portion is formed only in the lower case, or the structure in which the accommodating portion is formed in both the upper case and the lower case is also possible.

The first accommodating part 112 and the second accommodating part 114 have a rectangular structure, respectively, and have a long side 113 on a horizontal cross section of the first accommodating part 112 and a long side on a horizontal cross section of the second accommodating part 114. The first accommodating part 112 and the second accommodating part 114 are formed on the battery case 110 so that the 115 is parallel to each other.

The electrode assemblies accommodated in the accommodating parts 112 and 114 have positive terminal 122 and 124 formed on one side thereof, negative terminal terminals 126 and 128 formed on opposite sides thereof, and positive terminal terminals 122 and 124 formed therein. And the negative electrode terminals 124 and 128 protrude outside the sealed portion of the battery case 110. In addition, the positive terminal 122 of the first electrode assembly and the negative terminal 128 of the second electrode assembly protrude from one side of the outer circumferential surface of the battery case 110, and the negative terminal of the first electrode assembly is opposite to the opposite side. 126 and the positive electrode terminal 124 of the second electrode assembly protrude. That is, the anode terminals 122 and 124 and the cathode terminals 126 and 128 are formed so as to protrude one by one in an alternating orientation.

When a battery module or a battery pack is configured to include a secondary battery having such a structure as a unit cell, structural stability may be improved against external shocks such as drops and vibrations.

The inner frame 130 includes the first accommodating part 112 and the battery case 110 in a folded state such that the first accommodating part 112 and the second accommodating part 112 are stacked up and down the inner frame 130. It is attached to the structure surrounding the outer peripheral surface of the 2nd accommodating part 114. That is, the first accommodating part 112 and the second accommodating part 112 are seated in the internal space 132 of the internal frame 130. The structure of the inner frame 130 is schematically shown in FIG.

6 is a schematic diagram of a structure in which the secondary batteries of FIG. 2 are stacked and connected, and FIG. 7 is a front schematic diagram of a structure in which a cooling member is added to FIG. 6.

Referring to these drawings together with FIG. 2, a plurality of secondary batteries 101, 102, 103, 104, 105, and 106 are stacked to form a battery stack 100 ′, and respective secondary batteries 101 are provided. , 102, 103, 104, 105, and 106 are connected in series with each other. In addition, the cooling member 140 is in contact with the outer surface 119 of the portion bent in a “c” shape between the first accommodating part 112 and the second accommodating part 114 to cool the battery when the temperature rises. It consists of a structure to perform.

As the cooling member, as shown in FIG. 7, an air-cooled structure that maximizes a contact surface with external air may be used, but a water-cooled cooling member may be used, in which a coolant channel through which cooling water flows is formed.

FIG. 8 is a schematic diagram of a structure in which a cooling member including a cooling fin and a heat dissipation unit is added to the structure of FIG. 6.

Referring to FIG. 8, the cooling fin 142 formed of a sheet of metal material has one side contacting the outer surface of the accommodating portion, and the other side of the cooling fin 142 having the bent portion between the first accommodating portion and the second accommodating portion. The heat dissipation part 144 is in contact with the bent portion outer surface 119 of the cooling fin 142.

Since the cooling fins 142 are in contact with the outer surface of the first accommodating part or the second accommodating part, when the structure is stacked, the cooling fins 142 are respectively disposed between the secondary batteries 100 ′ of the battery cell stack. One side of the intervening structure is achieved.

It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (19)

A first electrode assembly and a second electrode assembly having a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode;
The laminate includes a laminate sheet having a first accommodating portion and a second accommodating portion for accommodating the first electrode assembly and the second electrode assembly, respectively, wherein the first accommodating portion and the second accommodating portion are bent to form a first accommodating portion and a second accommodating portion. A battery case having a structure in which two accommodating parts are stacked up and down; And
A cooling member mounted in contact with an outer surface of the bent portion between the first accommodating part and the second accommodating part of the battery case;
And a secondary battery. The method of claim 1, wherein the battery case,
A lower case in which the first accommodating part and the second accommodating part are formed; And
An upper case covering an upper surface of a lower case in a state in which a first electrode assembly and a second electrode assembly are respectively accommodated in the first accommodating portion and the second accommodating portion;
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Secondary battery, characterized in that the outer peripheral surface of the lower case and the upper case, and the first accommodating portion and the second accommodating portion is formed of a heat-sealed structure, respectively. The secondary battery of claim 2, wherein the upper case and the lower case are each formed of a member of one unit. The secondary battery of claim 1, further comprising an inner frame mounted between the first accommodating part and the second accommodating part to support a stacked structure of the accommodating parts. The method of claim 4, wherein the inner frame is formed in a structure surrounding the outer circumferential surface of the first accommodating portion and the second accommodating portion in a state where the battery case is folded so that the first accommodating portion and the second accommodating portion are stacked above and below the inner frame. Secondary battery characterized by the above-mentioned. The battery case of claim 1, wherein the first and second accommodating parts may be stacked up and down so that the first accommodating part and the second accommodating part of the battery case form a “c” shape on a vertical section. Secondary battery, characterized in that folded. The secondary battery of claim 1, wherein the first accommodating part and the second accommodating part are each formed in a rectangular structure. 8. The secondary battery according to claim 7, wherein the first storage portion and the second storage portion are formed on the battery case such that the long side on the horizontal cross section of the first accommodating portion and the long side on the horizontal cross section of the second accommodating portion are parallel to each other. battery. The method of claim 1, wherein the electrode assembly has a positive terminal is formed on one side and the negative terminal is formed on the opposite side, the positive terminal and the negative terminal is characterized in that protruding outside the sealing portion of the battery case Secondary battery. The method of claim 9, wherein the positive electrode terminal of the first electrode assembly and the negative electrode terminal of the second electrode assembly protrude from one side of the outer circumferential surface of the battery case, the negative terminal of the first electrode assembly and the second electrode assembly on opposite sides A secondary battery, characterized in that the positive terminal protruding. The method according to claim 10, wherein the positive terminal of the first electrode assembly and the negative terminal of the second electrode assembly are electrically connected in a state where the battery case is folded so that the first and second accommodating portions are stacked up and down. Secondary battery. The secondary battery according to claim 1, wherein the cooling member is formed of a metal material. The secondary battery of claim 1, wherein the cooling member has a refrigerant passage through which a refrigerant flows. The method of claim 1, wherein the cooling member,
A cooling fin whose one side is in contact with the outer surface of the first accommodating portion or the second accommodating portion, and the other portion is bent to be in close contact with the outer side surface of the bent portion between the first accommodating portion and the second accommodating portion;
A heat dissipation unit in contact with an outer surface of the bent portion of the cooling fins and cooling the heat conducted from the cooling fins;
And a secondary battery. 15. The secondary battery of claim 14, wherein the cooling fins are made of a sheet of metal. The secondary battery according to claim 1, wherein the secondary battery is a lithium secondary battery. A battery pack comprising the secondary battery according to any one of claims 1 to 16 as a unit module. A device comprising a battery pack according to claim 17. 19. The device of claim 18, wherein the device is an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, or a power storage device.

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