KR20140030431A - Secondary battery having case with multi electrode assembly-receiving portion - Google Patents

Abstract

The present invention provides a secondary battery which includes a battery case of a laminate sheet, in which a first and a second electrode assembly which have a structure comprising an anode, a cathode, and a separator formed between the anode and the cathode are embedded. A first receiving part receiving the first electrode assembly and a second receiving part receiving the second electrode assembly are formed in the battery case. The first receiving part and the second receiving part are separated from each other on the battery case. Each outer surface of the first and the second receiving part is fused to form a sealing structure.

Description

Secondary battery having a case formed with a plurality of electrode assembly accommodating portion {Secondary Battery Having Case with Multi Electrode Assembly-Receiving Portion}

The present invention relates to a secondary battery including a case in which a plurality of electrode assembly accommodating parts are formed, and more particularly, a first electrode assembly and a second electrode having a structure in which a separator is interposed between a positive electrode, a negative electrode, and a positive electrode and a negative electrode. The assembly is built in a battery case made of a laminate sheet, the battery case is formed with a first accommodating portion for accommodating the first electrode assembly and a second accommodating portion for accommodating the second electrode assembly, the first number The payment part and the second accommodating part are spaced apart from each other on the battery case, and the outer circumferential surface of the first accommodating part and the second accommodating part are related to a secondary battery, which is formed by a heat-sealed structure.

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 that has been proposed as a solution for air pollution of existing gasoline and diesel vehicles using fossil fuel. It is also drawing attention as a power source of (Plug-In HEV) or a power source of a power storage device.

In a small mobile device, one or a few battery cells are used per device, while a large and medium-sized device such as an automobile uses a battery module in which a plurality of battery cells are electrically connected to each other due to the necessity of a high output large capacity.

Since the battery module is preferably manufactured in a small size and a weight as much as possible, a prismatic battery, a pouch-shaped battery, and the like, which can be charged with a high degree of integration and have a small weight to capacity ratio, are mainly used as battery cells of a middle- or large-sized battery module. Particularly, a pouch-shaped battery using an aluminum laminate sheet or the like as an exterior member has recently attracted a great deal of attention due to its advantages such as low weight and low manufacturing cost.

However, when constructing a battery module or a battery pack using a pouch-type battery as described above, in the process of connecting between the electrode terminals of the pouch-type battery by welding, many difficulties and problems are derived, and also a pouch-type battery case Due to its structural characteristics, cracks were liable to occur due to external shocks such as drops or vibrations.

In order to solve the above problems, a structure in which a cell cover is mounted on the upper and lower surfaces of the pouch-type battery cell, cartridges for fixing each pouch-type battery cell, or a structure in which two or more battery cells are connected by an adhesive tape However, as the number of components increases, manufacturing costs increase and manufacturing processability decreases, and further problems arise in that a volume of a battery pack or a battery module having a structure in which a pouch-type battery cell is connected increases. .

Therefore, there is a high need for a secondary battery that solves the above problems and improves structural stability without increasing the total volume.

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, it is an object of the present invention to provide a secondary battery having excellent structural stability against external shocks such as vibration or dropping.

Still another object of the present invention is to provide a secondary battery that can improve stability without increasing the overall volume when the secondary battery is laminated to constitute a battery module or a battery pack.

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

The first electrode assembly and the second electrode assembly having a structure in which a separator is interposed between the positive electrode, the negative electrode, and the positive electrode and the negative electrode are embedded in one battery case made of a laminate sheet,

The battery case is provided with a first accommodating part for accommodating the first electrode assembly and a second accommodating part for accommodating the second electrode assembly.

The first accommodating part and the second accommodating part are spaced apart from each other on the battery case, and the outer circumferential surface of the first accommodating part and the outer circumferential surface of the second accommodating part are each 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 which ensures structural stability against external shock such as vibration or drop by forming a plurality of accommodating parts in the battery case in which the electrode electrode assembly is independently received.

In one specific example, the battery case,

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

An upper case covering an upper surface of the 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;

It may be formed in a structure including a.

In some cases, not only the lower case but also the upper case may have a structure in which an accommodating part is formed.

In one preferred example, the upper case and the lower case may each 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. . Compared to the secondary battery having a structure in which two battery cells having one housing part are connected, such a structure not only secures durability of the connection part between the storage parts, but also reduces the number of parts and provides a high manufacturing processability. To improve the effect.

The first accommodating part and the second accommodating part may be formed in a shape in which the electrode assembly may be seated in correspondence to the shape of the electrode assembly. For example, the first accommodating part and the second accommodating part may have a rectangular structure. Can be formed.

The battery case may be made of various materials, and may be, for example, a pouch type case of a laminate sheet including a resin layer and a metal layer. Examples of such a laminate sheet may be a sheet having a structure in which a durable outer coating layer, a metal blocking layer that blocks moisture and an electrolyte, and the like, and an inner sealant layer that provides sealing by thermal fusion are sequentially stacked. Examples of the outer coating layer material may include polyethylene terephthalate (PET), nylon, and the like, and examples of the barrier metal layer material may include aluminum, and examples of the inner sealant layer material may include non-stretched polypropylene. However, it is not limited only to these.

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 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 method of manufacturing the secondary battery,

(a) storing a first electrode assembly and a second electrode assembly in a battery case including an upper case and a lower case, wherein a first accommodating part and a second accommodating part are formed in the upper case and / or the lower case;

(b) thermally sealing the first and second accommodating portions of the battery case and the remaining portion of the outer circumferential surface of the first accommodating portion except for one end of the first accommodating portion and one end of the second accommodating portion;

(c) injecting an electrolyte into a first accommodating part and a second accommodating part through the ends of the unsealed state, and sealing the end parts by heat fusion;

(d) activating the secondary battery by performing charging and discharging, and then removing the gas and excess electrolyte generated in the activation process;

(e) sealing the outer circumferential surfaces of the first accommodating part and the second accommodating part in a direction in which the electrolyte is injected,

It provides a secondary battery manufacturing method comprising a.

Most secondary batteries, including pouch-type batteries, undergo a process of activating the battery by charging and discharging during the manufacturing of the battery cell. In order to manufacture the final battery cell, the gas generated during the activation process needs to be removed and degassing. It is called a degas process. Therefore, the sealing process of the secondary battery is carried out before and after the degassing process, compared to the manufacturing process of the secondary battery having a structure of connecting two battery cells having one housing, there is no need for parts for connecting the battery cells, The manufacturing process also has the effect of manufacturing a secondary battery with excellent durability.

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 uses a battery case having a structure in which a plurality of independent accommodating parts accommodating the electrode assembly are formed. Even if an impact is applied, there is an effect of preventing cracks and protecting the electrode assembly inside safely.

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 is a schematic view of a structure of folding the secondary battery of Figure 2;
4 to 6 are schematic views of the method of manufacturing the secondary battery of FIG. 2.

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.

2 is a schematic diagram of a secondary battery according to an embodiment of the present invention.

Referring to FIG. 2, 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.

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.

FIG. 3 is a schematic diagram of a structure in which the secondary battery of FIG. 2 is folded.

Referring to FIG. 3 together with FIG. 2, in a state where the first accommodating part 112 and the second accommodating part 114 are folded up and down, the cathode terminal 126 and the second electrode assembly of the first electrode assembly are folded. The positive terminal 124 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 terminal. A structure in which 126 is connected in series is shown.

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.

4 to 6 are schematic views of the method of manufacturing the secondary battery of FIG. 2.

4 to 6, the first electrode assembly 142 and the second electrode assembly 144 are accommodated in the first accommodating part 112 and the second accommodating part 114 of the battery case 110, respectively. Afterwards, between the first accommodating part 112 and the second accommodating part 114 of the battery case 110, and the electrode terminals 122, 124, 126, and 128 of the electrode assemblies 142 and 144. The outer peripheral surfaces 134 and 135 in the protruding direction are heat-sealed and sealed.

Then, after the electrolyte is injected into the first accommodating part 112 and the second accommodating part 114 through the unsealed part, the unsealed part 137 is heat-sealed and sealed to perform charging and discharging. Activate the secondary battery.

Thereafter, the gas and the surplus electrolyte generated in the activation process of the secondary battery are collected and removed by the collecting surplus portion 136 of the battery case 110.

Finally, as shown in FIG. 6, the electrode assemblies 142 and 144 and the inner side 138 and 139 adjacent to each other are heat-sealed to seal the remaining outer portions to complete the secondary battery as shown in FIG. 2.

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 (13)

The first electrode assembly and the second electrode assembly having a structure in which a separator is interposed between the positive electrode, the negative electrode, and the positive electrode and the negative electrode are embedded in one battery case made of a laminate sheet,
The battery case is provided with a first accommodating part for accommodating the first electrode assembly and a second accommodating part for accommodating the second electrode assembly.
And the first and second accommodating parts are spaced apart from each other on the battery case, and the outer circumferential surface of the first accommodating part and the outer circumferential surface of the second accommodating part are each heat-sealed and sealed. The method of claim 1, wherein the battery case,
A lower case in which a first accommodating part and a second accommodating part are formed; And
An upper case covering an upper surface of the lower case in a state in which a first electrode assembly and a second electrode assembly are respectively accommodated in the first and second accommodating parts;
And a secondary battery. 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, wherein the first accommodating part and the second accommodating part are each formed in a rectangular structure. The secondary battery according to claim 4, wherein the first accommodating part and the second accommodating part are formed on the battery case such that the long side on the horizontal cross section of the first accommodating part and the long side on the horizontal cross section of the second accommodating part are parallel to each other. . 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 sealed portion of the battery case Secondary battery. The method of claim 6, 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 and the second electrode assembly of the first electrode assembly on the opposite side A secondary battery, characterized in that the positive terminal protruding. 8. The secondary battery according to claim 7, wherein the positive electrode terminal of the first electrode assembly and the negative electrode terminal of the second electrode assembly are electrically connected in a state where the first accommodating portion and the second accommodating portion are folded up and down. battery. The secondary battery according to claim 1, wherein the secondary battery is a lithium secondary battery. A method of manufacturing a secondary battery according to claim 1,
(a) storing a first electrode assembly and a second electrode assembly in a battery case including an upper case and a lower case, wherein a first accommodating part and a second accommodating part are formed in the upper case and / or the lower case;
(b) thermally sealing the first and second accommodating portions of the battery case and the remaining portion of the outer circumferential surface of the first accommodating portion except for one end of the first accommodating portion and one end of the second accommodating portion;
(c) injecting an electrolyte into a first accommodating part and a second accommodating part through the ends of the unsealed state, and sealing the end parts by heat fusion;
(d) activating the secondary battery by performing charging and discharging, and then removing the gas and excess electrolyte generated in the activation process;
(e) sealing the outer circumferential surfaces of the first accommodating part and the second accommodating part in a direction in which the electrolyte is injected,
Secondary battery manufacturing method comprising a. A battery pack comprising the secondary battery according to any one of claims 1 to 9 as a unit module. Device comprising the battery pack according to claim 11. The device of claim 12, 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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