WO2016056776A1 - Battery cell including battery case formed in shape corresponding to electrode assembly having step structure - Google Patents

Abstract

The present invention relates to a battery cell that includes a battery case formed in a shape corresponding to an electrode assembly having a step structure. More specifically, the present invention provides a battery cell in which an electrode assembly having a structure in which a separation membrane is interposed between positive and negative electrodes is embedded in a battery case, comprising: an electrode assembly in which a plurality of electrodes or unit cells are vertically stacked on each other with respect to a plane, and two or more of the electrodes or the unit cells have different sizes of planes to form a step structure; and a battery case that includes first and second cases coupled to each other to surround the electrode assembly and has a structure in which a first receiving part corresponding to the shape of the upper portion of the electrode assembly is formed on the first case in the height direction with respect to the plane, and a second receiving part corresponding to the shape of the lower portion of the electrode assembly is formed on the second case.

Description

Battery cell including a battery case is formed in a shape corresponding to the electrode assembly of the staircase structure

This application claims the benefit of priority based on Korean Patent Application No. 10-2014-0134824 filed on October 7, 2014, and all contents disclosed in the literature of the Korean patent application are incorporated as part of this specification.

The present invention relates to a battery cell including a battery case is formed in a shape corresponding to the electrode assembly of the staircase structure.

Recently, secondary batteries capable of charging and discharging have been widely used as energy sources of wireless mobile devices. In addition, the secondary battery has attracted attention as an energy source of electric vehicles, hybrid electric vehicles, etc. which are proposed as a solution for air pollution of conventional gasoline and diesel vehicles using fossil fuel. Therefore, the type of applications using the secondary battery is very diversified due to the advantages of the secondary battery, and it is expected that the secondary battery will be applied to many fields and products in the future.

Such secondary batteries may be classified into lithium ion batteries, lithium ion polymer batteries, lithium polymer batteries, etc. according to the composition of the electrode and the electrolyte, and among them, there is little possibility of leakage of the electrolyte, and the amount of lithium ion polymer batteries that are easy to manufacture is high. Growing. In general, the secondary battery is a cylindrical battery and a rectangular battery in which the electrode assembly is embedded in a cylindrical or rectangular metal can, and a pouch type battery in which the electrode assembly is embedded in a pouch type case of an aluminum laminate sheet according to the shape of the battery case. The electrode assembly embedded in the battery case is composed of a positive electrode, a negative electrode, and a separator structure interposed between the positive electrode and the negative electrode is a power generator capable of charging and discharging, between the long sheet type positive electrode and the negative electrode coated with the active material It is classified into a jelly-roll type wound through a separator and a stack type in which a plurality of positive and negative electrodes of a predetermined size are sequentially stacked in a state interposed in the separator.

Among these, due to the high capacity of the battery, a large area of the case and processing into a thin material have attracted a lot of attention, and thus, a structure in which a stack type or a stack / fold type electrode assembly is incorporated in a pouch type battery case of an aluminum laminate sheet Pouch-type batteries have gradually increased due to low production cost, small weight, and easy shape deformation.

1 schematically illustrates 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 formed of a positive electrode, a negative electrode, and a separator disposed therebetween in the pouch type battery case 20. The two electrode leads 40 and 41 electrically connected to 31 and 32 are sealed to be exposed to the outside.

The battery case 20 is composed of a case body 21 including a concave shape accommodating 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 shell, a barrier metal layer 20b for preventing the penetration of materials, and an inner resin layer 20c for sealing. .

In the stack type 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 24 of the case body 21 and the upper end of the cover 22 are heat-sealed by a heat sealer (not shown), a short is generated between the heat welder and the electrode leads 40 and 41. The insulating film 50 is attached to the upper and lower surfaces of the electrode leads 40 and 41 to prevent it and to secure the sealing property between the electrode leads 40 and 41 and the battery case 20.

In addition, recently, due to the slim type or various design trends using the pouch type secondary battery, a new type of battery cell that minimizes dead space is required.

However, in order to make 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 change the design of the device to a larger size, and accordingly, the battery case in consideration of the shape of the electrode assembly. The problem that needs to be produced is raised. That is, to make 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 change the design of the device to a larger size.

Furthermore, there is a problem in that it is difficult to manufacture a battery cell that satisfies the desired conditions due to the complicated electrical connection method in the design change process.

The present invention aims to solve the problems of the prior art as described above and the technical problems that have been requested from the past.

An object of the present invention is to design a battery cell and a battery case in a specific structure that can be mounted in a variety of space of the device, by maximizing the utilization of the internal space of the device, a variety of deviation from the external structure of the device having a generally rectangular structure It is to provide a battery cell that can be efficiently mounted even in a device having an appearance.

A battery cell including a battery case is formed in a shape corresponding to the electrode assembly of the step structure according to the present invention for achieving this object,

A battery cell in which an electrode assembly having a structure in which a separator is interposed between a positive electrode and a negative electrode is built in a battery case,

An electrode assembly in which 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 a different planar size to form a staircase structure; And

Comprising a first case and a second case coupled to each other surrounding the electrode assembly, the first case is formed with a first receiving portion corresponding to the upper shape of the electrode assembly in the height direction relative to the plane, the second The case has a structure including a battery case which is 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 forms a stepped structure in the battery case, thereby facilitating securing the mounting space of the battery cell, maximizing the utilization of the internal space of the device, and using a high capacity battery cell in the device. This is possible and the device can be further miniaturized. In addition, due to the electrode assembly, the battery case and the structural features, it is possible to easily manufacture the desired battery cells despite the design change, thereby improving the performance and quality of the battery cells thereby ensuring safety.

In one specific example, the first case and the second case may be a pouch-type case consisting of a laminate sheet including a resin layer and a metal layer, the first case and the second case is one unit interconnected via a common side It may be a structure consisting of a member of.

In the above structure, the common side of the first case and the second case may be a side edge adjacent to the side where the electrode terminal is located.

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

In one specific example, the first accommodating part and the second case may have a symmetrical shape based on a common side of the first case and the second case.

In some cases, the first accommodating part and the second case may have an asymmetrical shape based on a common side of the first case and the second case.

According to the present invention, the number of steps formed on the basis of the stacking direction of the electrodes or the unit cells may be different from the first accommodating part of the first case and the second accommodating part of the second case.

In one specific example, a step may be formed in at least one of an inner side surface of the first accommodating unit and an inner side surface of the second accommodating unit adjacent to a common side of the first case and the second case.

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

The step of the inner side adjacent to the common side may have a structure formed smaller than the step formed on the other side. Therefore, since it is not affected by the stretching due to the step formed on the common side, it is possible to manufacture an excellent battery cell that does not cause a defect in the battery cell or a problem in the 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 plane sizes may have a structure having different widths and / or lengths of electrodes or unit cells based on a direction in which electrode terminals are formed, and two having different plane sizes. The above electrodes or unit cells may have structures having different thicknesses based on the stacking direction.

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

The two or more electrodes or unit cells having different plane sizes may be vertically aligned with respect to one side of the electrode terminal in a forming direction, and in some cases, the one side may have no step. Can be done.

The battery cell may be a lithium secondary battery having a structure in which a lithium salt-containing non-aqueous electrolyte is impregnated into an electrode assembly having a separator interposed between a positive electrode and a negative electrode.

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

Manufacturing an electrode assembly in which 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 plane sizes to form a step structure;

The first case and the second case is coupled to each other to surround the electrode assembly, the first case is formed with a first receiving portion corresponding to the upper shape of the electrode assembly in the height direction relative to the plane, the second A case having a second accommodating portion corresponding to a lower shape of the electrode assembly, a process of manufacturing a battery case for attaching the electrode assembly to the first accommodating portion and the second accommodating portion;

Bending the common edge so that the first case surrounds the electrode assembly and faces the second case while the electrode assembly is mounted on the accommodating part of the battery case; And

Injecting an electrolyte into the battery case and sealing the outer peripheral surface of the battery case by heat fusion;

It provides a battery cell manufacturing method comprising a.

The process of manufacturing the battery case,

(a) preparing a molding mold;

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

(c) preparing a molding jig having a shape corresponding to each other with the molding mold; And

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

It includes.

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

Preferred examples of the device may be selected from smartphones, mobile phones, notebooks, tablet PCs, wearable electronics, electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles or power storage systems.

Since the structure and fabrication method of such a device are known in the art, detailed description thereof will be omitted herein.

1 is a schematic diagram 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 staircase structure according to an embodiment of the present invention is accommodated;

3 is a schematic view of a battery case in which the housing part of the staircase structure according to the first embodiment of the present invention is formed;

4 is a schematic view of a battery case bent the battery case of Figure 3;

5 is a schematic view of a battery case in which the housing part of the staircase structure according to the second embodiment of the present invention is formed;

6 is a schematic view of a battery case bent the battery case of Figure 5;

7 is a schematic view of a battery case in which a housing part is formed in a shape corresponding to an electrode assembly having a step structure according to a third embodiment of the present invention;

8 is a schematic view of a battery case bent the battery case of FIG.

9 is a schematic view of a battery case in which the housing part of the staircase structure according to the fourth embodiment of the present invention is formed;

10 is a schematic view of a battery case in which the housing part of the staircase structure according to the fifth embodiment of the present invention is formed;

11 is a schematic flowchart of a method of manufacturing a battery cell including a battery case of a staircase structure 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, although described with reference to the drawings according to an embodiment of the present invention, this is for easier understanding of the present invention, the scope of the present invention is not limited thereto.

2 illustrates a battery cell including a battery case having a staircase structure according to an embodiment of the present invention, and FIG. 3 illustrates a battery case including a storage unit having a staircase structure according to an embodiment of the present invention. A schematic diagram is shown, and FIG. 4 is a schematic diagram 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 the positive electrode and the negative electrode is embedded in the battery case 120. The battery cell 100 is formed of a step 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, vertically aligned with respect to one side based on the forming direction of the positive electrode terminal 141 and the negative electrode terminal 142. There are steps 144, 145, 146, 154, 155, 156 in opposite directions of the aligned direction.

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

In the first case 121 and the second case 122, the first accommodating part 140 and the second accommodating part 150 are formed in a symmetrical shape with respect to the common side 125.

The first case 121 and the second case 122 are coupled to each other to surround the electrode assembly, and the first case 121 has a first accommodating part 140 corresponding to the upper shape of the electrode assembly in the height direction with respect to the plane. ) Is formed, and the second housing 122 has a second accommodating portion 150 corresponding to the lower shape of the electrode assembly.

The first accommodating part 140 includes a first accommodating area 147, a second accommodating area 148, and a third accommodating area 149 corresponding to the size of the unit cells. Similarly, the second accommodating part 150 has a shape symmetrical to the shape of the first accommodating part 140 and includes a first accommodating area 151, a second accommodating area 152, and a third accommodating area 153. It is.

In addition, the steps 144 may be formed on the inner surface of the first accommodating part 140 and the inner surface of the second accommodating part 150 adjacent to the common side 125 of the first case 121 and the second case 122. 145, 146, 154, 155, and 156 are formed.

The thickness T ₁ of the steps 146 and 156 adjacent to the common side 125 is smaller than the thickness T ₂ of the step formed on the opposite side. That is, since the steps 146 and 156 having a relatively small thickness are formed adjacent to the common side 125, the first case 121 is moved upward from the second case 122 about the common side 125. In the process of bending, the effect of stretching can be minimized.

FIG. 5 is a schematic view of a battery case in which a storage unit having a staircase structure according to a second embodiment of the present invention is formed, and FIG. 6 is a schematic view of a battery case of the assembled form of FIG. 5.

5 and 6, two or more electrodes or unit cells having different plane sizes are vertically aligned in the direction in which the positive electrode terminal 241 and the negative electrode 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, and the first case 221 is based on the common side 225 of the first case 221 and the second case 222. The 221 and the second case 222 are formed in a mutually asymmetrical shape. The battery case 220 has a structure in which the first case 221 is bent (see FIG. 5: arrow) above the second case 222 with respect to the common side 225 to match.

The accommodating part 240 of the first case 221 including the first accommodating area 247 and the second accommodating area 248 has two levels of steps 244 and 245 formed therein. The accommodating part 250 of the second case 222 including the accommodating area 251, the second accommodating area 252, and the third accommodating area 253 includes three levels of steps 254, 255, and 256. ) Is formed.

FIG. 7 is a schematic view of a battery case in which a storage unit having a staircase structure according to a third embodiment of the present invention is formed, and FIG. 8 is a schematic view of the assembled battery case of FIG. 7, respectively.

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

The battery case 320 is composed of one unit connected to each other based on the common side 325 positioned at the center, and the first case 321 is bent upward to the second case 322 (see FIG. 7: arrow). Is a matching structure.

9 is a schematic view of a battery case in which the accommodating part of the staircase structure according to the fourth exemplary embodiment of the present invention is formed.

Referring to FIG. 9, the battery case 420 includes a first case 421 and a second case 422, and the first case 421 and the second case 422 have a common side 425. It is formed in an asymmetrical shape as a reference. The first case 421 is bent toward the second case 422 based on the common side 425.

The first accommodating part 440 is composed of a first accommodating area 442 and a second accommodating area 443, and the second accommodating area 450 is the first accommodating area 451 and the second accommodating area 452. ) And the third storage region 453.

The width W ₄ , the length D ₄ , and the thickness T _{4 of} the second storage area 443 are the widths of the storage areas 451, 452, and 453 formed in the second storage part 450. W ₅ , W ₆ , W ₇ ), lengths D _5, D _6, D ₇ and thicknesses T ₅ , T ₆ , T ₇ are different asymmetrical shapes. That is, the first accommodating region 442 and the second accommodating region 443 of the first accommodating part 440 and the first accommodating region 451, the second accommodating region 452 of the second accommodating region 450, and The third accommodating regions 453 are all formed in a structure having different widths, lengths, and thicknesses.

FIG. 10 is a schematic view of a battery case in which an accommodating part having a step structure 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 the first case 521 and the second case 522 are formed of independent members separated from each other.

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

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

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 form electrode assemblies that form a step structure having different plane sizes (S110). Correspondingly, a battery case including a first case and a second case is manufactured to accommodate the electrode assemblies having the staircase structure (S120). Subsequently, in a state in which the electrode assembly is mounted on the accommodating part of the second case positioned below, the first case is bent around the common side so as to surround the electrode assembly and face the second case (S130). Finally, after the electrolyte is injected into the battery case and sealed by heat-sealing the outer peripheral surface of the battery case (S140), and after attaching a PCM containing a safety device attached to the label of the form surrounding the battery cell and the battery cell Manufacture.

Referring to the process of manufacturing the battery case, first, a molding mold for molding a battery case corresponding to the shape of the electrode assembly is prepared (S210), and the pouch film is disposed on the upper surface of the molding mold (S220). Thereafter, a molding jig having a shape corresponding to each other with the molding mold is prepared (S230), and the pouch film is compressed with the jig to simultaneously form an electrode assembly accommodating part (S240). Finally, the battery case is separated from the device and the appearance and dimensions of the battery case are examined to determine whether they are normal.

Those skilled in the art to which the present invention pertains will be able to make various applications and modifications within the scope of the present invention based on the above contents.

As described above, the battery cell according to the present invention by forming a stepped step in the case of stacking the battery cells, it is possible to secure the mounting space of the battery cell and maximize the utilization of the internal space of the device. In addition, a high capacity battery cell can be used for such a device, and the device can be further miniaturized.

In addition, due to the electrode assembly, the battery case and the structural features, it is possible to easily manufacture the desired battery cells despite the design change, thereby improving the performance and quality of the battery cells thereby providing an effect to ensure safety do.

Claims (22)

A battery cell in which an electrode assembly having a structure in which a separator is interposed between a positive electrode and a negative electrode is built in a battery case, An electrode assembly in which 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 a different planar size to form a staircase structure; And Comprising a first case and a second case coupled to each other surrounding the electrode assembly, the first case is formed with a first receiving portion corresponding to the upper shape of the electrode assembly in the height direction relative to the plane, the second A battery case having a structure in which a second accommodating part corresponding to a lower shape of the electrode assembly is formed; Battery cell comprising a. The battery cell according to claim 1, wherein the first case and the second case are pouch-type cases made of a laminate sheet including a resin layer and a metal layer. The battery cell of claim 1, wherein the first case and the second case are formed of one unit member interconnected through a common side. The battery cell according to claim 3, wherein the common side of the first case and the second case is a side side adjacent to the side where the electrode terminal is located. The battery cell according to claim 3, wherein the common side of the first case and the second case is a lower side facing the side where the electrode terminal is located. The battery cell according to claim 3, wherein the first accommodating part and the second case 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 3, 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 accommodating part of the first case and the second accommodating part of the second case have different numbers of steps formed based on the stacking direction of the electrodes or the unit cells. The battery cell according to claim 3, wherein a step is formed on at least one of an inner side surface of the first accommodating portion and an inner side surface of the second accommodating portion adjacent to a common side of the first case and the second case. The battery cell according to claim 9, wherein a step is formed on an inner side surface of the first accommodating portion and an inner side surface of the second accommodating portion adjacent to a common side of the first case and the second case. The battery cell of claim 1, wherein the first case and the second case are formed of mutually independent members. The battery cell of claim 1, wherein the two or more electrodes or unit cells having different plane sizes have different widths and / or lengths of the electrodes or unit cells based on the direction in which the electrode terminals are formed. The battery cell of claim 1, wherein two or more electrodes or unit cells having different plane sizes have different thicknesses based on a stacking direction. The method of claim 1, wherein the unit cell, in a structure in which one or more anodes and one or more cathodes are laminated with a separator interposed therebetween, the unit cells having the same type of electrode located on both sides, or the type of electrodes located on both sides of the unit cell A battery cell, characterized in that another unit cell. The battery cell of claim 1, wherein two or more electrodes or unit cells having different plane sizes are vertically aligned with respect to one side of the electrode terminal. The method of claim 15, wherein the one side battery cell, characterized in that there is no step. The battery cell of claim 1, wherein the battery cell is a lithium secondary battery. As a method of manufacturing a battery cell according to claim 1, Manufacturing an electrode assembly in which 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 plane sizes to form a step structure; The first case and the second case is coupled to each other to surround the electrode assembly, the first case is formed with a first receiving portion corresponding to the upper shape of the electrode assembly in the height direction relative to the plane, the second A case having a second accommodating portion corresponding to a lower shape of the electrode assembly, a process of manufacturing a battery case for attaching the electrode assembly to the first accommodating portion and the second accommodating portion; Bending the common edge so that the first case surrounds the electrode assembly and faces the second case while the electrode assembly is mounted on the accommodating part of the battery case; And Injecting an electrolyte into the battery case and sealing the outer peripheral surface of the battery case by heat fusion; Battery cell manufacturing method comprising a. The method of claim 18, wherein the manufacturing of the battery case comprises: (a) preparing a molding mold; (b) disposing a pouch film on the upper surface of the molding mold; (c) preparing a molding jig having a shape corresponding to each other with the molding mold; And (d) simultaneously forming the electrode assembly accommodating part by pressing the pouch film with the molding jig; Battery cell manufacturing method comprising a. A battery pack comprising a battery cell according to any one of claims 1 to 19 as a unit battery. A device comprising the battery pack according to claim 20 as a power source. The device of claim 21, wherein the device is selected from a smartphone, a mobile phone, a notebook, a tablet PC, a wearable electronic device, an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, or a power storage system. .

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