KR20230108429A - Battery cell and battery module including the same - Google Patents

Abstract

The present invention includes a battery cell and a battery module including the same, and the battery cell according to an embodiment of the present invention includes an electrode assembly including a positive electrode, a negative electrode, and a separator; a battery case including a housing portion accommodating the electrode assembly, and a sealing portion heat-sealed to seal the outer periphery; and a filter member folded based on a bending line, wherein the battery case includes a first region and a second region that correspond to each other, and the first region and the second region are separated by being folded based on a folding portion. .

Description

Battery cell and battery module including the same {BATTERY CELL AND BATTERY MODULE INCLUDING THE SAME}

The present invention relates to a battery cell and a battery module including the same, and more particularly, to a battery cell and a battery module including the same to prevent flame generation by suppressing external ejection of a material inside the battery cell at a high temperature.

As technology development and demand for mobile devices increase, demand for secondary batteries as an energy source is rapidly increasing. Accordingly, a lot of research on secondary batteries that can meet various needs has been conducted.

Secondary batteries are attracting much attention as energy sources for power devices such as electric bicycles, electric vehicles, and hybrid electric vehicles as well as mobile devices such as mobile phones, digital cameras, and laptop computers.

Recently, as the need for a high-capacity secondary battery structure, including the use of secondary batteries as an energy storage source, has increased, the demand for medium-large module structure battery packs in which a plurality of secondary batteries are connected in series / parallel to a battery module is increasing. .

Meanwhile, when a battery pack is configured by connecting a plurality of battery cells in series/parallel, a battery module composed of at least one battery cell is configured, and other components are added using at least one battery module to form a battery pack. configuration is common. Since the battery cells constituting such a medium- or large-sized battery module are composed of secondary batteries capable of charging and discharging, such high-output and large-capacity secondary batteries generate a large amount of heat during charging and discharging processes.

1 is a view showing a conventional battery cell in a high temperature state. FIG. 2 is a view of a conventional battery cell in a high-temperature state, viewed in the x-axis direction of FIG. 1 .

1 and 2, a conventional battery cell 10 includes a pouch case 30 accommodating an electrode assembly including a positive electrode, a negative electrode, and a separator, and protrudes from a side portion 31 of the pouch case. It includes an electrode lead 21 to be.

When the battery cell 10 is in a high temperature state, when the electrolyte located inside the battery cell 10 vaporizes, the internal pressure of the battery cell 10 increases, and accordingly, the battery cell 10 may swell. In this case, due to the increase in internal pressure of the battery cell 10, the side portion 31 of the sealing portion of the battery cell 10 where the electrode lead 21 is located may be torn.

The degree of sealing of the side part 31 provided with the electrode lead 21 in one region may be lower than the degree of sealing of the sealing part not provided with the electrode lead 21 . This is because the side part 31 is sealed while the electrode lead 21 is provided in one area of the side part 31, so that the one area where the electrode lead 21 is located may not be properly sealed.

When the side portion 31 of the battery cell 10 is torn, metal or ceramic particles inside the battery cell 10 may be ejected out of the battery cell 10 together with the vaporized electrolyte. In this case, the particles ejected to the outside may be ejected into adjacent battery cells and battery modules to cause thermal runaway, and may also generate flames as a cause of ignition of the electrolyte solution.

Therefore, in order to solve the above problem, there is a need to prevent external ejection and flame generation of metal or ceramic particles inside the battery cell 10 .

The problem to be solved by the present invention is to provide a battery cell with improved safety and a battery module including the same.

However, the problems to be solved by the embodiments of the present invention are not limited to the above problems and can be variously extended within the scope of the technical idea included in the present invention.

A battery cell according to an embodiment of the present invention includes an electrode assembly including a positive electrode, a negative electrode, and a separator; a battery case including a housing portion accommodating the electrode assembly, and a sealing portion heat-sealed to seal the outer periphery; and a filter member folded based on a bending line, wherein the battery case includes a first region and a second region corresponding to each other, and the first region and the second region are separated by being folded based on a folding portion. .

The filter member may be folded and unfolded at the same time as the battery case is torn due to an increase in pressure inside the battery cell.

The sealing part may include a first sealing part that is an edge of both side surfaces of the battery case and a second sealing part that is one edge of the sealing part facing the folding part.

An electrode lead may be located in the first sealing part.

The filter member may be located in a region where the battery case is first torn due to an increase in internal pressure of the battery cell.

The filter member may be located in the first sealing part.

The sealing degree of the first sealing part may be weaker than that of the second sealing part.

The filter member includes a filter membrane and a ventilation hole, and the size of the ventilation hole may be smaller than the size of metal or ceramic particles inside the battery cell.

The filter member may be folded toward the inside of the battery case.

The filter member may be folded along a bending line to form at least two folded surfaces, the other surface of the one folded surface may be a first surface, and the other surface of the other folded surface may be a second surface.

The first surface may be thermally fused to the first sealing portion of the first region, and the second surface may be thermally fused to the first sealing portion of the second region.

When the number of bending lines is plural, the first surface and the second surface may be other surfaces of the outermost folded surface.

The filter member may be a porous material.

The filter member may be a heat-resistant and chemical-resistant material.

A battery module according to another embodiment of the present invention includes the battery cell described above.

According to embodiments, by providing a filter member inside the battery cell, even if the battery cell is torn, particles inside the battery cell are not ejected to the outside, providing a battery cell with improved safety and a battery module including the same can do.

The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

1 is a view showing a conventional battery cell in a high temperature state.
FIG. 2 is a view of a conventional battery cell in a high-temperature state, viewed in the x-axis direction of FIG. 1 .
3 is a view showing a disassembled state of an assembly step of a battery cell according to an embodiment of the present invention.
4 is a perspective view of a battery cell according to an embodiment of the present invention.
5 is a perspective view of a battery cell according to an embodiment of the present invention.
6 is a view of the battery cell of FIG. 4 as viewed in the x-axis direction, and is a view when the side portion of the battery cell is sealed.
7(a) is a view showing a filter member according to an embodiment of the present invention, and FIG. 7(b) is a view showing a folded shape of the filter member of FIG. 7(a).
FIG. 8 is a view of the battery cell of FIG. 4 viewed in the x-axis direction, and is a view showing a side portion of the battery cell when it is opened.

Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. This invention may be embodied in many different forms and is not limited to the embodiments set forth herein.

In order to clearly describe the present invention, parts irrelevant to the description are omitted, and the same reference numerals are assigned to the same or similar components throughout the specification.

In addition, since the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of explanation, the present invention is not necessarily limited to the shown bar. In the drawings, the thickness is shown enlarged to clearly express the various layers and regions. And in the drawings, for convenience of explanation, the thicknesses of some layers and regions are exaggerated.

In addition, when a part such as a layer, film, region, plate, etc. is said to be "on" or "on" another part, this includes not only the case where it is "directly on" the other part, but also the case where another part is in the middle. . Conversely, when a part is said to be "directly on" another part, it means that there is no other part in between. In addition, to be "on" or "on" a reference part means to be located above or below the reference part, and to necessarily be located "above" or "on" in the opposite direction of gravity does not mean no.

In addition, throughout the specification, when a certain component is said to "include", it means that it may further include other components without excluding other components unless otherwise stated.

In addition, throughout the specification, when it is referred to as "planar image", it means when the target part is viewed from above, and when it is referred to as "cross-sectional image", it means when a cross section of the target part cut vertically is viewed from the side.

3 is a view showing a disassembled state of an assembly step of a battery cell according to an embodiment of the present invention. 4 is a perspective view of a battery cell according to an embodiment of the present invention. 5 is a perspective view of a battery cell according to an embodiment of the present invention.

3 to 5, the battery cell 100 inserted to be stacked in the battery module includes an electrode assembly 200 including a positive electrode, a negative electrode, and a separator, and a storage unit 310 in which the electrode assembly 200 is accommodated. A battery case 300 is formed.

The electrode assembly 200 may be a stacked electrode assembly 200 in which a plurality of positive electrodes and negative electrodes cut in units of a certain size are sequentially stacked with separators interposed therebetween. However, it is not limited thereto, and may be a winding-type assembly in which a structure in which an anode and a cathode are stacked with a separator interposed therebetween is wound.

The electrode lead 210 may be electrically connected to the electrode assembly 200 . These electrode leads 210 may be provided as a pair. Some of the pair of electrode leads 210 are located outside the battery case 300 at the front and rear of the battery case 300 (both ends in the longitudinal direction of the electrode assembly, x-axis direction or -x-axis direction), respectively. can be extruded. The configuration of the battery cell 100 described above is an example, and the shape of the battery cell 100 may be variously modified.

The battery case 300 may include a storage unit 310 , a sealing unit 320 and a folding unit 330 . The battery case 300 may include a first region 301 and a second region 302 corresponding to each other, and the first housing part 310a and the second region 302 located in the first region 301 . ) It may be made of a sheet-like base material including a second accommodating part 310b located at, and a folding part 330 located between the first accommodating part 300a and the second accommodating part 300b.

The first region 301 and the second region 302 may be divided by a folding unit 330 . The first area 301 and the second area 302 may be divided by the central area of the folding unit 330 .

When the battery case 300 is manufactured, a storage unit 310 in which the electrode assembly 200 is accommodated may be formed in at least one of the first area 301 and the second area 302 through forming. The storage part 310 may include a first storage part 310a located in the first area 301 and a second storage part 310b located in the second area 302 . A part of the electrode assembly 200 is embedded in each of the first housing part 310a and the second housing part 310b, and the first housing part 310a and the second housing part 310b support the folding part 330. The electrode assembly 200 may be accommodated so as to be wrapped by being folded to face each other with the electrode assembly 200 interposed therebetween.

After the housing unit 310 is formed, the folding unit 330 of the battery case 300 is bent by 180 degrees based on the center of the folding unit 330 to cover the housing unit 310, thereby improving the structure of the battery case 300. can be completed

The folding portion 330 may be a portion that bends the battery case 300 . The first area 301 and the second area 302 may contact and correspond to each other while being folded along the center of the folding part 330 .

The electrode assembly 200 has a planar shape having four sides, and the folding unit 330 may be positioned at a portion corresponding to one of the four sides. The folding unit 330 is in close contact with one side surface 230 of the electrode assembly 200, and the sheet-like base material is folded at both edges of the folding unit 330, thereby forming the first housing unit 310a and the second housing unit 310b. ) can be folded to face each other. Accordingly, the width P of the folding portion 330 may be the same as the thickness t of the electrode assembly 200 . On the three sides excluding the side corresponding to the folding part 330, the edges of the first housing part 310a and the second housing part 310b are bonded to each other to form a sealing part 320. The sealing part 320 is sealed by a method such as thermal fusion.

More specifically, the sheet-like base material of the battery case 300 may be made of a laminated sheet including a metal layer and a resin layer. In particular, the laminate sheet may be an aluminum laminate sheet. The sheet-like base material is composed of a core portion made of a metal layer, a thermally fused layer formed on one surface of the core portion, and an insulating film formed on the other surface of the core portion. The heat sealing layer acts as an adhesive layer using a polymer resin, such as modified polypropylene, such as CPP (Casted Polypropylene), and the insulating film may be formed of a resin material such as nylon or polyethylene terephthalate (PET). The structure and material of the pouch exterior material are not limited. In the sealing part 320, the heat sealing layers of the first housing part 310a and the second housing part 310b come into contact with each other, and the battery case 300 is formed by performing a heat welding process in a state where they are in contact. It will be sealed.

The sealing part 320 may include a first sealing part 321 and a second sealing part 323 .

The first sealing part 321 may be a sealing part 320 positioned on both side surfaces (x-axis direction or -x-axis direction) of the battery case 300 . The first sealing part 321 may be both side edges of the battery case 300 . The first sealing part 321 may be the sealing part 320 where the electrode lead 210 is located.

The second sealing part 323 may be a sealing part 320 facing the folding part 330 . The second sealing part 323 may be one edge of the sealing part 320 facing the folding part 330 . The second sealing part 323 may be a sealing part 320 that does not include the electrode lead 210 .

The sealing degree of the first sealing part 321 may be weaker than that of the second sealing part 323 . This is because the first sealing part 321 includes the electrode lead 210 . That is, since the heat sealing layer does not contact each other in some areas of the first sealing part 321 where the electrode lead 210 is located, the heat sealing layers are in contact with each other in the first area 301 and the second area 302. Areas not covered may be more than the second sealing portion 323 .

After all of the sealing parts 320 are sealed, when the battery cell 100 is in a high-temperature state, the electrolyte located inside the battery cell 100 vaporizes, thereby increasing the internal pressure of the battery cell 100 and increasing the battery cell 100. Due to this swelling, the sealed battery case 300 may be torn. In this case, the first sealing portion 321 having a relatively weak degree of sealing compared to the second sealing portion 323 may be torn.

According to this embodiment, the filter member 400, which is a porous filter, may be provided in the first sealing part 321. The filter member 400 serves to prevent metal or ceramic particles inside the battery cell 100 from being ejected to the outside in a high temperature state.

Specifically, referring to FIGS. 3 and 4 , the filter member 400 may be provided in the first sealing part 321 of the first region 301 . In this case, the filter member 400 may be heat-sealed together with the first sealing portion 321 of the second region 302 after the battery case 300 is folded. That is, one surface of the filter member 400 is in contact with the first sealing part 321 of the first region 301, and the other surface of the filter member 400 is in contact with the first sealing part 321 of the second region 302. can be encountered

Therefore, after all of the sealing parts 320 are sealed, when the first sealing part 321 is torn due to the increase in internal pressure of the battery cell 100 in a high temperature state, the folded filter member 400 is the first sealing part. Part 321 may be unfolded with a tear. That is, in the filter member 400 , the first sealing portion 321 heat-sealed to the first region 301 and the second region 302 may be torn and unfolded together. As the filter member 400 is unfolded, the particles inside the battery cell 100 are filtered by the filter member 400 and may not be ejected to the outside, and the particles are not transferred to adjacent battery cells and battery modules, resulting in thermal runaway. can prevent

However, the filter member 400 is not limited to being provided only in the first sealing part 321, and may be provided in a region of the battery case 300 where tearing first occurs due to internal pressure of the battery cell. .

Hereinafter, a configuration of one battery cell 110 will be described with reference to FIG. 5 . The battery cell 100 may include an electrode assembly 200 , a cell case 130 , and an electrode lead 210 protruding from the electrode assembly 200 , respectively.

The electrode assembly 200 may include a positive electrode plate, a negative electrode plate, and a separator. The cell case 130 is for packaging the electrode assembly 200 and may be made of a laminate sheet including a resin layer and a metal layer. The cell case 130 may include a case body 132 and cell terraces 133 .

The case body 132 may accommodate the electrode assembly 200 . To this end, an accommodation space capable of accommodating the electrode assembly 200 is provided in the case body 132 .

The cell terrace 133 extends from the case body 132 and is sealed to seal the electrode assembly 200 . The electrode leads 210 may partially protrude from one side and the other side of the cell terraces 133, specifically, from the front and rear sides of the cell terraces 133 (x-axis direction and -x-axis direction).

The electrode lead 210 may be electrically connected to the electrode assembly 200 . These electrode leads 210 may be provided as a pair. A portion of the pair of electrode leads 210 may protrude out of the cell terrace 133 in the front and rear (x-axis direction and -x-axis direction) of the cell case 130 , respectively. The configuration of the battery cell 100 described above is an example, and the shape of the battery cell 100 for configuring the battery cell stack may be variously modified.

6 is a view of the battery cell of FIG. 4 as viewed in the x-axis direction, and is a view when the side portion of the battery cell is sealed. 7(a) is a view showing a filter member according to an embodiment of the present invention, and FIG. 7(b) is a view showing a folded shape of the filter member of FIG. 7(a).

6, 7(a) and 7(b) , in the battery cell according to an embodiment of the present invention, the filter member 400 may be provided in the first sealing part 321, and the filter member (400) may be provided in a shape that is folded toward the inside of the battery cell.

Specifically, the filter member 400 may be folded based on the bending line (B). When the filter member 400 is folded along the bending line B, at least two folding surfaces 413 may be formed based on the bending line B. The folded surface 413 means an inner surface of the filter member 400 in a structure in which the filter member 400 is folded. Accordingly, the folded surface 413 may be surfaces facing each other in a structure in which the filter member 400 is folded.

The filter member 400 folded along the bending line B may include a first surface 411 and a second surface 412 (see FIG. 7(b)). The first surface 411 may be the other surface of one folded surface 413 , and the second surface 412 may be the other surface of the other folded surface 413 .

When the filter member 400 is folded along the bending line B, the first surface 411 may be a surface in contact with the first sealing portion 321 of the first region 301, and the second surface 412 may be a surface of the second region 302 in contact with the first sealing portion 321 . Accordingly, the first surface 411 may be heat-sealed to the first sealing part 321 of the first region 301, and the second surface 412 may be thermally fused to the first sealing part 321 of the second region 302. ) and can be heat-sealed.

In this drawing, the bending line (B) is illustrated as one, but is not limited thereto, and the bending line (B) may be plural. In this case, the first surface 411 and the second surface 412 may be the other surface of the outermost folded surface 413 , respectively.

The folding surface 413 may correspond to the widths of the first surface 411 and the second surface 412 , and may be smaller or larger than the widths of the first surface 411 and the second surface 412 .

The filter member 400 is folded into the battery cell based on the bending line B, so that the first surface 411 in which the folded surface 413 folded along the bending line B contacts the sealing portion 320, and Even if the area is larger than the second surface 412 , it is not heat-sealed together with the first surface 411 and the second surface 412 , so damage to the filter member 400 when unfolded can be prevented.

FIG. 8 is a view of the battery cell of FIG. 4 viewed in the x-axis direction, and is a view showing a side portion of the battery cell when it is opened.

Referring to FIG. 8 , in a high-temperature state, the internal pressure of the battery cell increases due to vaporization of the electrolyte located inside the battery cell, and as a result, the first sealing portion 321 may be torn. In a high temperature state, the first sealing part 321 may be torn mainly in one area where the electrode lead 210 is provided.

In this case, the first sealing part 321 of the first area and the first sealing part 321 of the second area are torn, and the filter member heat-sealed to the first sealing part 321 of the first area ( The second surface 412 of the filter member 400 heat-sealed to the first surface 411 of 400 and the first sealing part 321 of the second area may be unfolded. That is, the folded filter member 400 may be unfolded.

The filter member 400 may include a filter membrane 410 and a ventilation hole 430 .

The filter membrane 410 serves to prevent metal or ceramic particles inside the battery cell from being discharged to the outside in a high temperature state. That is, it is possible to promote the safety of the battery by preventing particles inside the battery cell from being discharged to adjacent battery cells or battery modules, thereby preventing thermal runaway or ignition from occurring.

Ventilation holes 430, in a high-temperature state, can discharge gas generated due to vaporization of the electrolyte located inside the battery cell to the outside, thereby preventing the occurrence of flame due to venting gas. The size of the ventilation hole 430 may be smaller than the size of metal or ceramic particles inside the battery cell. Therefore, the venting gas can move through the ventilation hole 430, but particles inside the battery cell are not emitted, and thus thermal runaway to adjacent battery cells and battery modules or generation of flames can be prevented.

The filter member 400 may be a porous material. In addition, the filter member 400 may be a heat-resistant and chemical-resistant material. Therefore, the filter member 400 does not melt or change its shape even in a high temperature state, and the safety of the battery can be improved.

The battery cell described above and a battery module including the battery cell may be applied to various devices. Such a device may be applied to means of transportation such as an electric bicycle, an electric vehicle, or a hybrid vehicle, but the present invention is not limited thereto and is applicable to various devices capable of using a battery module and a battery pack including the battery module, which is also applicable to the present invention. It belongs to the scope of the right of invention.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concept of the present invention defined in the following claims are also made according to the present invention. falls within the scope of the rights of

100: battery cell
200: electrode assembly
300: battery case
301 first area
302 second area
320: storage unit
321: first storage unit
323: second storage unit
400: filter member
410: filter membrane
430: vent hole

Claims (15)

An electrode assembly including an anode, a cathode, and a separator;
a battery case including a housing portion accommodating the electrode assembly, and a sealing portion heat-sealed to seal the outer periphery; and
Including a filter member folded on the basis of the bending line,
The battery case includes a first region and a second region corresponding to each other, and the first region and the second region are divided by being folded based on a folding portion. In paragraph 1,
The filter member is a battery cell that is folded and unfolded at the same time as the battery case is torn due to an increase in pressure inside the battery cell. In paragraph 1,
The sealing part,
A first sealing part, which is an edge of both sides of the battery case, and
A battery cell including a second sealing part that is one edge of the sealing part facing the folding part. In paragraph 3,
A battery cell in which an electrode lead is positioned in the first sealing portion. In paragraph 3,
The filter member is located in a region where the battery case is first torn due to an increase in pressure inside the battery cell. In paragraph 5,
The filter member is a battery cell located in the first sealing portion. In paragraph 3,
The first sealing portion is a battery cell having a weak sealing degree compared to the second sealing portion. In paragraph 1,
The filter member includes a filter membrane and a ventilation hole,
The size of the ventilation hole is smaller than the size of metal or ceramic particles inside the battery cell. In paragraph 1,
The filter member is a battery cell that is folded toward the inside of the battery case. In paragraph 9,
The filter member is folded based on a bending line to form at least two folded surfaces,
The other side of the one folded surface is a first surface, and the other side of the other folded surface is a second surface. In paragraph 10,
The first surface is thermally fused with the first sealing portion of the first region,
The second surface is thermally fused with the first sealing portion of the second region. In paragraph 10,
When the number of bending lines is plural, the first surface and the second surface are other surfaces of the outermost folded surface of the battery cell. In paragraph 1,
The filter member is a battery cell of a porous material. In paragraph 1,
The filter member is a battery cell that is heat-resistant and chemical-resistant material. A battery module comprising the battery cell according to claim 1.