KR101725901B1 - Battery Cell Comprising Battery Case of Shape Corresponding to Electrode Assembly of Stair-like Structure - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery cell including a battery case formed in a shape corresponding to a stepped electrode assembly, and more particularly to a battery cell having a structure in which a separator is interposed between an anode and a cathode, Wherein a plurality of electrodes or unit cells are stacked in a height direction with respect to a plane and at least two or more of the electrodes or unit cells have different planar sizes to form a stepped structure; And a first case and a second case which are coupled to each other to surround the electrode assembly. The first case has a first housing part corresponding to an upper shape of the electrode assembly in a height direction with respect to a plane, And the second case includes a battery case having a structure in which a second housing portion corresponding to a lower shape of the electrode assembly is formed.

Description

[0001] The present invention relates to a battery cell including a battery case formed in a shape corresponding to an electrode assembly of a staircase structure,

The present invention relates to a battery cell including a battery case formed in a shape corresponding to a stepped electrode assembly.

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 attracting attention as an energy source for electric vehicles, hybrid electric vehicles, and the like, which is proposed as a solution for air pollution in existing gasoline vehicles and diesel vehicles using fossil fuels. Therefore, the types of applications using secondary batteries are diversifying due to the advantages of secondary batteries, and it is expected that secondary batteries will be applied to many fields and products in the future.

Such a secondary battery may be classified as a lithium ion battery, a lithium ion polymer battery, or a lithium polymer battery depending on the configuration of an electrode and an electrolytic solution. The amount of the lithium ion polymer battery Is growing. 2. Description of the Related Art Generally, a secondary battery includes a cylindrical battery and a prismatic battery in which an electrode assembly is embedded in a cylindrical or rectangular metal can according to the shape of a battery case, and a pouch type battery in which an electrode assembly is embedded in a pouch- , And an electrode assembly embedded in the battery case is a power generation device that includes a positive electrode, a negative electrode, and a separator structure sandwiched between the positive electrode and the negative electrode, and is capable of charging and discharging. The electrode assembly includes a long sheet-like positive electrode coated with an active material, A jelly-roll type which is wound with a separator interposed therebetween, and a stacked type in which a plurality of positive electrodes and negative electrodes of a predetermined size are sequentially stacked with a separator interposed therebetween.

Among them, due to the high capacity of the battery, enlargement of the size of the case and the processing of a thin material are attracting much attention. Accordingly, a stacked or stacked / folded type electrode assembly is embedded in a pouch-shaped battery case of an aluminum laminate sheet The pouch-shaped battery of the present invention has been gradually increased in usage due to low manufacturing cost, small weight, and easy shape deformation.

FIG. 1 schematically shows a structure of a pouch-type secondary battery including a conventional stacked electrode assembly.

Referring to FIG. 1, the pouch type secondary battery 10 includes an electrode assembly 30 including an anode, a cathode, and a separator disposed between the anode and the cathode, 31 and 32 are sealed to be exposed to the outside.

The battery case 20 includes a case body 21 including a concave shaped storage portion 23 on which the electrode assembly 30 can be seated and a cover 22 integrally connected to the body 21 have. The battery case 20 is made of a laminate sheet and is composed of an outer resin layer 20a forming an outermost periphery, a barrier metal layer 20b for preventing penetration of a material, and an inner resin layer 20c for sealing .

In the stacked electrode assembly 30, a plurality of positive electrode tabs 31 and a plurality of negative electrode tabs 32 are fused to each other and coupled to the electrode leads 40 and 41. In addition, when the upper end portion 24 of the case body 21 and the upper end portion of the cover 22 are thermally fused by a heat welding machine (not shown), a short circuit occurs between the heat fusion welding machine and the electrode leads 40 and 41 An insulating film 50 is attached to the upper and lower surfaces of the electrode leads 40 and 41 in order to prevent the electrode leads 40 and 41 and ensure the sealing property between the electrode leads 40 and 41 and the battery case 20.

In recent years, there has been a demand for a new type of battery cell that minimizes dead space due to slim type using various pouch type secondary batteries or various design trends.

However, considering the design of the device to which the battery cell is applied, it is necessary to reduce the capacity of the battery cell or to change the design of the device to a larger size in order to construct a new structure. Accordingly, A problem is raised. That is, in order to obtain a new structure in consideration of the design of the device to which the battery cell is applied, it is necessary to reduce the capacity of the battery cell or to change the design of the device to a larger size.

Furthermore, since the electrical connection method is complicated in the design change process, it is difficult to manufacture a battery cell satisfying a desired condition.

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

It is an object of the present invention to design a battery cell and a battery case with a specific structure that can be mounted in various spaces of a device to maximize utilization of the internal space of the device, And to provide a battery cell that can be efficiently mounted even in a device having an external shape.

To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, a battery cell includes a battery case formed in a shape corresponding to an electrode assembly having a stepped structure,

A battery cell in which an electrode assembly having a separator interposed between an anode and a cathode is embedded in a battery case,

Wherein a plurality of electrodes or unit cells are stacked in a height direction with respect to a plane and at least two or more of the electrodes or unit cells have different planar sizes to form a stepped structure; And

Wherein the first case has a first housing part corresponding to an upper shape of the electrode assembly in a height direction with respect to a plane, and the first housing has a first housing part and a second housing part, The case has a structure including a battery case having a structure in which a second housing portion corresponding to the lower shape of the electrode assembly is formed.

That is, the battery cell according to the present invention has a stepped step in the battery case, thereby facilitating the securing of the mounting space of the battery cell, maximizing the utilization of the space inside the device, And the device can be further miniaturized. Also, due to the structural features of the electrode assembly and the battery case, it is possible to easily manufacture a desired battery cell in spite of a change in design, thereby improving the performance and quality of the battery cell, thereby securing safety.

In one specific example, the first case and the second case may be a pouch type case made of a laminate sheet including a resin layer and a metal layer, and the first case and the second case may be a unit As shown in Fig.

In this structure, the common sides of the first case and the second case may be lateral sides adjacent to the sides where the electrode terminals are located.

In some cases, the common side of the first case and the second case may be the lower side opposite to the side where the electrode terminal is located.

In one specific example, the first housing and the second housing may be formed in a symmetrical shape with respect to a common side of the first housing and the second housing.

In some cases, the first housing part and the second housing are formed in an asymmetrical shape with respect to a common side of the first case and the second case.

According to the present invention, the first housing portion of the first case and the second housing portion of the second case may have different numbers of steps formed based on the stacking direction of the electrodes or the unit cells.

In one specific example, a step may be formed on at least one of the inner surface of the first receiving portion and the inner surface of the second receiving portion adjacent to the common sides of the first case and the second case.

In addition, a step may be formed on the inner surface of the first accommodating portion and the inner surface of the second accommodating portion adjacent to the common sides of the first case and the second case.

The stepped portion of the inner side adjacent to the common side may be formed to be smaller than the stepped portion formed on the other side. Therefore, it is possible to manufacture an excellent battery cell which does not suffer from a drawback of the elongation due to the step formed on the common side, and which does not cause defects in the battery cells or problems in battery performance and service life.

In another specific example, the first case and the second case may be made of mutually independent members.

In the above structure, two or more electrodes or unit cells having different planar sizes may have different widths and / or lengths of electrodes or unit cells based on the forming direction of the electrode terminals, The above electrodes or unit cells may have different thicknesses with respect to the stacking direction.

In one specific example, the unit cell has a structure in which one or more positive electrodes and one or more negative electrodes are stacked in a state in which a separator is interposed therebetween, and a unit cell having the same type of electrodes located on both sides, It may be another unit cell.

The two or more electrodes or unit cells having different planar sizes may be vertically aligned with respect to one side with respect to the direction in which the electrode terminals are formed, and in some cases, Lt; / RTI >

The battery cell may be a lithium secondary battery having a structure in which a nonaqueous electrolyte solution containing a lithium salt is impregnated in an electrode assembly having a separator interposed between an anode and a cathode.

On the other hand, the present invention is a method for manufacturing the battery cell,

A plurality of electrodes or unit cells are stacked in a height direction with respect to a plane and at least two or more electrodes or unit cells of the unit cells have different planar sizes to form a stepped structure;

Wherein the first case and the second case are formed to have a first housing portion corresponding to an upper shape of the electrode assembly in a height direction with respect to a plane, The case is formed with a second accommodating portion corresponding to a lower shape of the electrode assembly, and a process of manufacturing a battery case for mounting the electrode assembly to the first accommodating portion and the second accommodating portion;

Bending the common case so that the first case covers the electrode assembly and faces the second case in a state where the electrode assembly is mounted on the battery case of the battery case; And

Sealing the outer circumferential surface of the battery case by injecting an electrolyte solution into the battery case;

And a method for manufacturing a battery cell.

The process of manufacturing the battery case includes:

(a) preparing a forming mold;

(b) disposing a pouch film on an upper surface of the molding die;

(c) preparing a molding jig having a shape corresponding to the molding die; And

(d) simultaneously forming the electrode assembly receiving portion by pressing the pouch film with the molding jig;

.

The present invention also provides a battery pack comprising a battery cell as a unit battery and a device including the battery pack as a power source.

Preferable examples of the device may be selected from smart phones, mobile phones, notebooks, tablet PCs, wearable electronic devices, electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles or systems for power storage.

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, in the battery cell according to the present invention, the stepped step is formed in the case of stacking the battery cells, thereby securing the space for mounting the battery cells and maximizing the utilization of the space inside the device. Further, it is possible to use a high-capacity battery cell in such a device, and it is possible to further miniaturize the device.

In addition, due to the structural characteristics of the electrode assembly and the battery case, it is possible to easily manufacture a desired battery cell in spite of a change in design, thereby improving the performance and quality of the battery cell, do.

1 is a schematic view of a pouch type secondary battery including a conventional stacked electrode assembly;
2 is a perspective view of a battery cell including a battery case in which an electrode assembly having a stepped structure according to an embodiment of the present invention is housed;
3 is a schematic view of a battery case in which a stepped structure accommodating portion according to the first embodiment of the present invention is formed;
4 is a schematic view of a battery case in which the battery case of Fig. 3 is bent;
5 is a schematic view of a battery case in which a stepped structure accommodating portion according to a second embodiment of the present invention is formed;
6 is a schematic view of a battery case in which the battery case of Fig. 5 is bent;
7 is a schematic view of a battery case in which a storage portion is formed in a shape corresponding to a stepped electrode assembly according to a third embodiment of the present invention;
FIG. 8 is a schematic view of a battery case in which the battery case of FIG. 7 is bent.
9 is a schematic view of a battery case in which a stepped structure accommodating portion according to a fourth embodiment of the present invention is formed;
10 is a schematic view of a battery case in which a stepped structure storage portion according to a fifth embodiment of the present invention is formed;
11 is a schematic flow chart of a method of manufacturing a battery cell including a stepped structure battery case according to an embodiment of the present invention;
12 is a schematic flowchart of a process of manufacturing a battery case according to an embodiment of the present invention.

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.

FIG. 2 illustrates a battery cell including a battery case having a stepped structure according to an embodiment of the present invention. FIG. 3 illustrates a battery case having a stepped structure storing part according to an embodiment of the present invention. And FIG. 4 is a schematic view of the assembled battery case of FIG. 3, respectively.

2 to 4, the battery cell 100 has a structure in which an electrode assembly (not shown) having a separator interposed between an anode and a cathode is embedded in the battery case 120. The battery cells 100 are formed in a stepped structure 127 in which unit cells (not shown) are sequentially stacked in a height direction with respect to a plane and have different plane sizes.

The unit cells are vertically aligned in the forming direction of the positive electrode terminal 141 and the negative electrode terminal 142 and are vertically aligned with respect to the one side portion with reference to the forming direction of the positive electrode terminal 141 and the negative electrode terminal 142, There are step differences 144, 145, 146, 154, 155 and 156 in the opposite directions in the aligned direction.

The battery case 120 includes a first case 121 and a second case 122. The first case 121 and the second case 122 are connected to each other through a common side 125 And the absence of units.

The first housing part 121 and the second housing part 122 are formed with the first housing part 140 and the second housing part 150 symmetrically with respect to the common side 125, respectively.

The first case 121 and the second case 122 are coupled to each other to surround the electrode assembly. The first case 121 has a first receiving part 140 (corresponding to an upper shape of the electrode assembly) And a second housing part 150 corresponding to the lower shape of the electrode assembly is formed in the second case 122, respectively.

The first storage portion 140 is composed of a first storage area 147, a second storage area 148 and a third storage area 149 corresponding to the size of the unit cells. Likewise, the second housing part 150 is formed in a shape symmetrical to the shape of the first housing part 140 and composed of the first housing area 151, the second housing area 152 and the third housing area 153 .

On the inner surface of the first storage portion 140 adjacent to the common side 125 of the first case 121 and the second case 122 and the inner side surface of the second storage portion 150, 145, 146, 154, 155, 156 are formed.

FIG. 5 is a schematic view of a battery case having a stair-stepped housing portion according to a second embodiment of the present invention, and FIG. 6 is a schematic view of a battery case of the completed assembly of FIG.

5 and 6, two or more electrodes or unit cells having different planar sizes are vertically aligned in the direction in which the positive terminal 241 and the negative terminal 242 are formed, and are accommodated in the battery case 220.

The battery case 220 includes a first case 221 and a second case 222. The battery case 220 includes a first case 221 and a second case 222, 221 and the second case 222 are formed asymmetrically with respect to each other. The battery case 220 has a structure in which the first case 221 is bent toward the upper portion of the second case 222 (refer to the arrow in FIG. 5) with the common side 225 as the center.

The housing part 240 of the first case 221 constituted by the first housing area 247 and the second housing area 248 is formed with two stepped sections 244 and 245, The housing part 250 of the second case 222 constituted by the housing area 251, the second housing area 252 and the third housing area 253 has three steps 254, 255 and 256 Is formed.

The thickness T ₁ of the steps 146 and 156 adjacent to the common side 125 is formed to be smaller than the thickness T ₂ of the step formed on the opposite side. That is, the stepped portions 146 and 156 having a relatively small thickness are formed adjacent to the common side 125, so that the first case 221 is positioned above the second case 222 around the common side 225 It is possible to minimize the influence of stretching in the process of bending.

Fig. 7 is a schematic view of a battery case having a stair-stepped storage portion according to a third embodiment of the present invention, and Fig. 8 is a schematic view of the assembled battery case shown in Fig.

7 and 8, the positive electrode terminal 341 and the negative electrode terminal 342 of the unit cells protrude in the direction perpendicular to the common side 325 with respect to the common side 325.

The battery case 320 is a member of a unit connected to each other with reference to a common side 325 positioned at the center. The first case 321 bends to the upper part of the second case 322 ).

Fig. 9 is a schematic view of a battery case in which a stepped structure accommodating portion according to a fourth embodiment of the present invention is formed.

9, the battery case 420 is composed of a first case 421 and a second case 422. The first case 421 and the second case 422 have a common side 425 And is formed in an asymmetrical shape with reference to the reference. And the first case 421 is bent to the upper portion of the second case 422 with respect to the common side 425.

The first housing section 440 is composed of a first housing area 442 and a second housing area 443 and the second housing area 450 is formed of a first housing area 451 and a second housing area 452 And a third accommodating area 453, as shown in Fig.

The widths of the second width of the receiving area (443) (W _4), the length (D ₄₎ and the thickness (T ₄₎ is in the receiving area which is formed on the second housing 450 (451, 452, 453) ( W ₅ , W ₆ , W ₇ ), lengths (D _5, D _6, D ₇ ) and thicknesses (T ₅ , T ₆ , T ₇ ). That is, the first accommodating area 442 and the second accommodating area 443 of the first accommodating part 440 and the first accommodating area 451, the second accommodating area 452 of the second accommodating area 450, The third housing area 453 is formed in a structure having different widths, lengths, and thicknesses.

Fig. 10 is a schematic view of a battery case in which a stepped structure accommodating portion according to a fifth embodiment of the present invention is formed.

Referring to FIG. 10, the battery case 520 includes a first case 521 and a second case 522. The first case 521 and the second case 522 are the same as the above-described embodiments except that they are formed as independent members separated from each other.

11 is a flowchart illustrating a method of manufacturing a battery cell including a battery case having a stepped structure according to the present invention, and FIG. 12 is a schematic diagram illustrating a process of manufacturing the battery case according to the present invention have.

Hereinafter, a method of manufacturing the battery case according to the present invention will be described in detail with reference to FIGS. 11 and 12. FIG.

The plurality of electrodes or unit cells are stacked in a height direction with respect to a plane, and at least two or more of the electrodes or unit cells form electrode assemblies having different step sizes in step S110. In response to this, a battery case made up of the first case and the second case is manufactured so that the electrode assemblies of the stepped structure are housed (S120). Then, in a state where the electrode assembly is mounted on the receiving portion of the second case located below, the first case surrounds the electrode assembly and bends around the common side so as to face the second case (S130). Finally, after the electrolyte is injected into the battery case, the outer circumferential surface of the battery case is thermally fused and sealed (S140). After the PCM including the safety element is attached, a label for wrapping the PCM and the battery cell is attached, .

First, a molding mold for molding a battery case corresponding to the electrode assembly shape is prepared (S210), and a pouch film is disposed on the upper surface of the molding mold (S220). Thereafter, a forming jig having a shape corresponding to the forming mold is prepared (S230), and the electrode assembly receiving portion is simultaneously formed by pressing the pouch film with the jig (S240). Finally, the battery case is detached from the apparatus, and the appearance and dimensions of the battery case are inspected to determine whether or not the battery case is normal.

Those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims (22)

A battery cell in which an electrode assembly having a separator interposed between an anode and a cathode is embedded in a battery case,
Wherein a plurality of electrodes or unit cells are stacked in a height direction with respect to a plane and at least two or more of the electrodes or unit cells have different planar sizes to form a stepped structure; And
Wherein the first case has a first housing part corresponding to an upper shape of the electrode assembly in a height direction with respect to a plane, and the first housing has a first housing part and a second housing part, A battery case having a structure in which a second accommodating portion corresponding to a lower shape of the electrode assembly is formed;
Lt; / RTI >
The first case and the second case are made up of one unit member connected to each other through a common side,
The unit cell is a unit cell in which the types of electrodes located on both sides are the same or the types of electrodes located on both sides are different from each other in a structure in which one or more positive electrodes and one or more negative electrodes are stacked with a separator interposed therebetween,
Wherein an inner side surface of the first accommodating portion and an inner side surface of the second accommodating portion adjacent to the common sides of the first case and the second case have stepped portions, respectively. The battery cell according to claim 1, wherein the first case and the second case are pouch-shaped cases made of a laminate sheet including a resin layer and a metal layer. delete The battery cell according to claim 1, wherein the common side of the first case and the second case is a side adjacent to a side where the electrode terminal is located. The battery cell according to claim 1, wherein a common side of the first case and the second case is a lower side opposite to a side where the electrode terminal is located. The battery cell according to claim 1, wherein the first housing part and the second housing are formed in a symmetrical shape with respect to a common side of the first case and the second case. The battery cell according to claim 1, wherein the first accommodating portion and the second case are formed in an asymmetrical shape with respect to a common side of the first case and the second case. The battery cell according to claim 7, wherein the first housing part of the first case and the second housing part of the second case have different numbers of steps formed on the basis of the stacking direction of the electrodes or the unit cells. delete delete delete The battery cell according to claim 1, wherein two or more electrodes or unit cells having different planar sizes have different widths and / or lengths of electrodes or unit cells based on the direction of formation of the electrode terminals. The battery cell according to claim 1, wherein two or more electrodes or unit cells having different planar sizes are different in thickness based on the stacking direction. delete The battery cell according to claim 1, wherein the two or more electrodes or unit cells having different planar sizes are vertically aligned with respect to one side with respect to a forming direction of the electrode terminals. The battery cell according to claim 15, wherein no step is present on said one side portion. The battery cell according to claim 1, wherein the battery cell is a lithium secondary battery. A method of manufacturing a battery cell according to claim 1,
A plurality of electrodes or unit cells are stacked in a height direction with respect to a plane and at least two or more electrodes or unit cells of the unit cells have different planar sizes to form a stepped structure;
Wherein the first case and the second case are formed to have a first housing portion corresponding to an upper shape of the electrode assembly in a height direction with respect to a plane, The case is formed with a second accommodating portion corresponding to a lower shape of the electrode assembly, and a process of manufacturing a battery case for mounting the electrode assembly to the first accommodating portion and the second accommodating portion;
Bending the common case so that the first case covers the electrode assembly and faces the second case in a state where the electrode assembly is mounted on the battery case of the battery case; And
Sealing the outer circumferential surface of the battery case by injecting an electrolyte solution into the battery case;
And forming a battery cell. delete A battery pack comprising a battery cell according to any one of claims 1, 2, 4 to 8, 12, 13, and 15 to 17 as a unit cell. A device comprising the battery pack according to claim 20 as a power source. 22. The device of claim 21, wherein the device is selected from a smart phone, a mobile phone, a laptop, a tablet PC, a wearable electronic device, an electric vehicle, a hybrid electric vehicle, a plug- .

Images