KR20220118700A - Battery cell and battery module including the same - Google Patents

Abstract

A battery cell according to an embodiment of the present invention includes: a battery case in which an electrode assembly is mounted in an accommodating unit and which includes a sealing unit having a structure that the outer circumferential surface is sealed by thermal fusion; an electrode lead electrically connected to an electrode tab included in the electrode assembly and protruding from the outside of the battery case via the sealing unit; and a lead film positioned at a part corresponding to the sealing unit in at least one of the upper part and lower part of the electrode lead, wherein a recessed unit is formed on the outer circumferential surface of the accommodating unit, and the recessed unit is recessed in a depth direction of the accommodating unit. The present invention can delay the venting phenomenon.

Description

BATTERY CELL AND BATTERY MODULE INCLUDING THE SAME

The present invention relates to a battery cell with improved safety and a battery module including the same, and more particularly, to a battery cell that delays a venting phenomenon caused by a gas generated inside the battery cell, and a battery module including the same.

As technology development and demand for mobile devices increase, the demand for secondary batteries as an energy source is rapidly increasing. In particular, secondary batteries are of great interest not only as mobile devices such as mobile phones, digital cameras, notebooks, and wearable devices, but also as energy sources for power devices such as electric bicycles, electric vehicles, and hybrid electric vehicles.

According to the shape of the battery case, the secondary battery is classified into a cylindrical battery and a prismatic battery in which the electrode assembly is embedded in a cylindrical or prismatic metal can, and a pouch-type battery in which the electrode assembly is embedded in a pouch-type case of an aluminum laminate sheet. do. Here, the electrode assembly embedded in the battery case is a power generating element that can be charged and discharged by having a positive electrode, a negative electrode, and a separator structure interposed between the positive electrode and the negative electrode. It is classified into a jelly-roll type, which is wound therebetween, and a stack type, in which a plurality of positive and negative electrodes are interposed in a separator and sequentially stacked.

Among these, in particular, a pouch-type battery having a structure in which a stack-type or stack/folding-type electrode assembly is embedded in a pouch-type battery case of an aluminum laminate sheet is gradually being used due to low manufacturing cost, small weight, easy deformation, etc. is increasing

1 is a top view showing a state in which a conventional battery cell is assembled. FIG. 2 is a view showing a part of a cross-sectional view taken along the a-a' axis of FIG. 1 .

Referring to FIG. 1 , the battery cell includes a battery case 20 including an accommodating part 25 in which an electrode assembly 11 is mounted. Here, the battery case 20 includes a sealing portion 20s formed by heat-sealing the outer peripheral surface in order to seal the electrolyte solution embedded together with the electrode assembly. In addition, the electrode leads 14 and the lead films 15 positioned on the upper and lower portions of the electrode leads 14 are positioned on both sides of the electrode assembly 11 , and the electrode leads 14 are externally via the sealing portion 20s. is protruding into

Referring to FIG. 2 , in the conventional battery cell, a large amount of gas is generated inside the battery cell during the charging and discharging process, thereby inducing a high pressure inside the sealed battery case 20 , and thus one side of the accommodating part 25 . It can be expanded like this expansion region 20v. In particular, in the conventional battery cell, the expansion region 20v is not sufficient to accommodate the high-pressure gas induced inside the battery case 20, so the sealing portion 20s in which the electrode lead 14 and the lead film 15 are located. ), there is a problem that gas venting (venting) occurs. That is, in the conventional battery cell, due to such gas venting, the sealing portion 20s is more likely to be damaged, and external gas or moisture is introduced into the battery cell to deteriorate the battery performance, or the electrolyte inside the battery cell is leaked. There are problems such as

Accordingly, there is a need to develop a battery cell capable of sufficiently accommodating the gas generated inside the battery cell and delaying the gas venting phenomenon.

The problem to be solved by the present invention relates to a battery cell with improved safety and a battery module including the same, and more particularly, to a battery cell that delays a venting phenomenon caused by a gas generated inside the battery cell, and a battery including the same to provide a module.

The problem to be solved by the present invention is not limited to the above-mentioned problems, and the problems not mentioned will be clearly understood by those of ordinary skill in the art to which the present invention belongs from the present specification and the accompanying drawings. .

A battery cell according to an embodiment of the present invention includes: a battery case having an electrode assembly mounted on a receiving part, and including a sealing part having an outer circumferential surface sealed by thermal fusion; an electrode lead electrically connected to the electrode tab included in the electrode assembly and protruding outwardly of the battery case via the sealing part; and a lead film positioned at a portion corresponding to the sealing part in at least one of the upper part and the lower part of the electrode lead, wherein at least one indentation is formed on an outer peripheral surface of the accommodating part, and the indentation part is the accommodating part. is indented along the depth direction of

The indentation portion may be located on an outer peripheral surface of the receiving part on an outer peripheral surface where the electrode lead is positioned.

The indentation part may be positioned between the receiving part and the sealing part.

The indentation portion may be indented smaller than the depth of the receiving portion.

The indentation portion may extend along a width direction of the electrode lead.

The indentation portion may be smaller than the width of the receiving portion, and may extend greater than the width of the electrode lead.

The electrode lead may include a positive electrode lead and a negative electrode lead, and the recessed portion may be respectively positioned in the sealing portion through which the positive lead passes and the sealing portion through which the negative lead passes.

The positive lead and the negative lead may be disposed to face each other on both sides of the battery case.

The battery case may further include a cover part positioned symmetrically with the accommodating part with respect to a boundary line, and bent based on the boundary line, so that the accommodating part and the cover part face each other.

The battery case may be bent based on the boundary line so that the indentation part faces the cover part.

The battery case may be made of a pouch-type case of a laminate sheet including a resin layer and a metal layer.

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

According to embodiments, the present invention relates to a battery cell with improved safety and a battery module including the same, and more particularly, it is possible to delay a venting phenomenon caused by a gas generated inside the battery cell.

The effects of the present invention are not limited to the above-described effects, and the effects not mentioned will be clearly understood by those of ordinary skill in the art to which the present invention belongs from the present specification and the accompanying drawings.

1 is a top view showing a state in which a conventional battery cell is assembled.
FIG. 2 is a view showing a part of a cross-sectional view taken along the a-a' axis of FIG. 1 .
3 is a top view showing a state in which the battery cell according to the present embodiment is assembled.
4 is a view showing a part of a cross-sectional view taken along the axis A-A' of FIG. 3 .
FIG. 5 is a view showing an area expanded inside a battery cell based on the cross section of FIG. 4 .

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

In order to clearly explain 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 indicated for convenience of description, the present invention is not necessarily limited to the illustrated bar. In order to clearly express various layers and regions in the drawings, the thicknesses are enlarged. And in the drawings, for convenience of explanation, the thickness of some layers and regions is exaggerated.

In addition, throughout the specification, when a part "includes" a certain component, this means that other components may be further included, rather than excluding other components, unless otherwise stated.

In addition, throughout the specification, when it is referred to as "planar view", it means when the target part is viewed from above, and when it is referred to as "cross-section", it means when the cross-section obtained by cutting the target part vertically is viewed from the side.

Hereinafter, a battery cell according to an embodiment of the present invention will be described. However, the description will be made with reference to one end of the battery cell, but it is not necessarily limited thereto, and the same or similar content may be described in the case of the other end.

3 is a top view showing a state in which the battery cell according to the present embodiment is assembled. FIG. 4 is a view showing a part of a cross-sectional view taken along the A-A′ axis of FIG. 3 .

3 and 4, in the battery cell according to an embodiment of the present invention, the electrode assembly 110 is mounted on the receiving part 250, the sealing part 200s having a structure in which the outer peripheral surface is sealed by thermal fusion. ) includes a battery case 200 including a. Here, the battery cell may include an electrolyte solution together with the electrode assembly 110 inside the battery case 200 .

For example, the electrolyte means an electrolyte in a liquid state, ions may move between the positive electrode and the negative electrode, and the secondary battery may be charged and discharged through ion exchange between the positive electrode and the negative electrode. Examples of the electrolyte used in the present invention include organic liquid electrolytes, inorganic liquid electrolytes, solid polymer electrolytes, gel-type polymer electrolytes, solid inorganic electrolytes, molten inorganic electrolytes, and the like, which can be used in the manufacture of lithium secondary batteries. not.

Here, the electrode assembly 110 may have a jelly-roll type (winding type), a stack type (laminated type), or a composite type (stack/folding type) structure. More specifically, the electrode assembly 110 may include an anode, a cathode, and a separator disposed therebetween.

3 and 4 , the battery case 200 further includes a cover part 260 positioned symmetrically with the receiving part 250 with respect to the boundary line 200a. Here, the battery case 200 may be bent based on the boundary line 200a, so that the accommodating part 250 and the cover part 260 may face each other. More specifically, the battery case 200 may have a sealed structure in which the outer peripheral surface 210 of the accommodating part 250 and the surface in contact with the cover part 260 are heat-sealed. However, the shape of the battery case 200 is not limited thereto, and the cover part 260 may be replaced with a separate accommodating part like the accommodating part 250 .

Also, the battery case 200 may be a laminate sheet including a resin layer and a metal layer. More specifically, the battery case 200 is made of a laminate sheet, and may be composed of an outer resin layer forming the outermost layer, a barrier metal layer preventing penetration of materials, and an inner resin layer for sealing. Here, the sealing part 200s may be formed by fusion-bonding the resin layer of the cover part 260 and the resin layer of the outer peripheral surface 210 of the accommodating part 250 to each other by heat and pressure.

3 and 4 , the battery cell according to this embodiment is electrically connected to the electrode tab 120 included in the electrode assembly 110 , and the battery case 200 is passed through the sealing part 200s. and an electrode lead 140 protruding outward of the . In addition, in at least one of the upper and lower portions of the electrode lead 140 , a lead film 150 positioned at a portion corresponding to the sealing portion 200s is further included.

For example, the electrode lead 140 includes a positive electrode lead electrically connected to a weak electrode tab among the electrode tabs 120 included in the electrode assembly 110 , and a negative electrode tab among the electrode tabs 120 included in the electrode assembly 110 , and It includes an electrically connected negative lead.

Accordingly, the lead film 150 can improve sealing properties between the sealing part 200s and the electrode lead 140 while preventing a short circuit from occurring in the electrode lead 140 during thermal fusion.

Here, as shown in FIG. 3 , in the battery cell according to an embodiment of the present invention, the positive electrode lead and the negative electrode lead, which are the electrode leads 140 , may be disposed on opposite sides of the battery case 200 to face each other. In other words, the battery cell may be a bidirectional pouch battery cell in which the positive lead and the negative lead protrude from both sides of the battery case 200 , respectively.

However, the present invention is not limited thereto, and the battery cell according to another embodiment may be a unidirectional pouch battery cell in which the positive electrode lead and the negative electrode lead are disposed together on the same side of the battery case 200 . Hereinafter, the description will be made based on the bidirectional pouch battery cell, but the same or similar description may be made in the case of the unidirectional pouch battery cell.

Hereinafter, the recess 270 formed in the battery case 200 will be described in detail.

3 and 4 , in the battery cell according to the present embodiment, the battery case 200 has at least one indentation portion 270 formed on the outer circumferential surface 210 of the receiving portion 250, and the indentation portion 270 is recessed along the depth direction of the accommodating part 250 .

For example, in the outer circumferential surface 210 of the accommodating part 250 , the indentation part 270 may be positioned on the outer circumferential surface where the electrode lead 140 is positioned. More specifically, the indentation portion 270 may be located on the outer peripheral surface where the sealing portion 200s through which the electrode lead 140 passes is formed. For example, the indentation portion 270 may be respectively located in the sealing portion 200s through which the positive lead passes and the sealing portion 200s through which the negative lead passes.

Accordingly, in this embodiment, gas venting that may be generated in the sealing part 200s in which the electrode lead 140 and the lead film 150 are located, which are vulnerable to the pressure applied by the gas inside the battery case 200, is effectively prevented. can be delayed

3 and 4 , the indentation part 270 may be positioned between the receiving part 250 and the sealing part 200s. In other words, the outer peripheral surface 210 of the accommodating part 250 on which the indentation part 270 is formed may not be heat-sealed. That is, the outer circumferential surface 210 of the battery case may be heat-sealed and sealed with the cover part 260 by avoiding the outer circumferential surface 210 of the accommodating part 250 on which the indentation part 270 is formed.

Accordingly, in the present embodiment, the battery case 200 may not interfere with gas collection by the indentation portion 270 while maintaining the sealing force by the sealing portion 200s, thereby venting gas of the battery cell. ) can be effectively delayed.

Referring to FIGS. 3 and 4 , the battery case 200 may be bent based on the boundary line 200a as described above, so that the indentation portion 270 may face the cover portion 260 . Here, based on the sealing part 200s, the recessed part 270 is recessed from the cover part 260 by a predetermined depth.

For example, the recessed portion 270 may be recessed smaller than the depth of the receiving portion 250 . In addition, the recess 270 may extend along the width direction of the electrode lead 140 . Also, the indentation portion 270 may be smaller than the width of the accommodating portion 250 , but may extend greater than the width of the electrode lead 140 . However, the depth, size, width, etc. of the indentation portion 270 are not limited thereto, and may be adjusted within a range that can sufficiently secure the sealing force of the battery case 200 .

Accordingly, the indentation 270 may be exposed toward the inside of the battery case 200 , so that the gas generated inside the battery case 200 is collected in a space equal to the depth at which the indentation 270 is indented. can That is, the recess 270 may effectively delay gas venting of the battery cell.

FIG. 5 is a view showing an area expanded inside a battery cell based on the cross section of FIG. 4 .

4 and 5 , when comparing before and after expansion by the high-pressure and/or high-temperature gas generated inside the battery case 200, the battery cell 100 according to the present embodiment has an expansion region 200v. It is possible to collect gas corresponding to an area corresponding to .

More specifically, in the battery cell 100 according to the present embodiment, when the gas inside the battery case 200 is a relatively small amount, the gas is primarily in the space remaining in the accommodating part 250 as shown in FIG. 4 . Doedoe collected, gas may be additionally collected even in the space in which the indentation part 270 is indented.

Comparing FIGS. 2 and 4 , in the conventional battery cell, when the amount of gas inside the battery case 20 is greater than the amount that can be accommodated in the space remaining in the accommodating part 25 , the side surface of the battery case 20 immediately this will inflate. Contrary to this, in the present embodiment, the gas inside the battery case 200 may be additionally collected in the space formed by the indentation portion 270, so that the expansion time of the side surface of the battery case 200 can be further delayed. have.

In addition, in the battery cell 100 according to the present embodiment, when the high-pressure and/or high-temperature gas inside the battery case 200 is relatively large, the side surface of the accommodating part 250 is expanded as shown in FIG. Secondarily, the gas inside the battery case 200 can be collected, and the side of the accommodating part 250 can be secured as the indentation part 270 is recessed together with the accommodating part 250 length. ) can be further expanded by the length of

2 and 5 , the expansion region 200v of the battery cell according to the present embodiment is relatively significantly increased compared to the expansion region 20v of the conventional battery cell, and the amount of the battery cell 10 is larger than that of the conventional battery cell 10 . of gas can be captured. That is, the recess 270 may effectively delay gas venting of the battery cell.

Accordingly, in the present embodiment, the high-temperature and/or high-pressure gas generated inside the battery cell can be sequentially collected in the space formed by the indentation 270 , so that the gas venting of the battery cell is further improved. can be effectively delayed. In addition, during the time during which gas venting is delayed by the indentation part 270 , sufficient time can be secured for the user of the device including the battery cell or performing the action on the battery cell to prepare for an accident caused by the battery cell. , user safety can also be further improved.

A battery module according to another embodiment of the present invention includes the battery cells described above. Meanwhile, one or more battery modules according to the present embodiment may be packaged in a pack case to form a battery pack.

The above-described battery module and battery pack including the same may be applied to various devices. Such a device may be applied to transportation means such as an electric bicycle, an electric vehicle, and a hybrid vehicle, but the present invention is not limited thereto and is applicable to various devices that can use a battery module and a battery pack including the same. belong to the scope of the invention.

Although the preferred embodiment of the present invention has been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims are also presented. It belongs to the scope of the right of the invention.

110: electrode assembly
140: electrode lead
150: lead film
200: battery case
250: storage unit
260: cover part
270: indentation

Claims (12)

a battery case in which the electrode assembly is mounted on the receiving unit, the battery case including a sealing unit having an outer circumferential surface sealed by thermal fusion;
an electrode lead electrically connected to the electrode tab included in the electrode assembly and protruding outwardly of the battery case via the sealing part; and
At least one of the upper and lower portions of the electrode lead, including a lead film positioned at a portion corresponding to the sealing portion,
At least one indentation is formed on the outer peripheral surface of the receiving part,
The indentation part is a battery cell indented along the depth direction of the receiving part. In claim 1,
The indentation portion is a battery cell located on the outer peripheral surface of the electrode lead is located on the outer peripheral surface of the accommodating part. In claim 2,
The indentation portion is a battery cell positioned between the receiving portion and the sealing portion. In claim 3,
The indentation portion is a battery cell indented smaller than the depth of the receiving portion. In claim 4,
The indentation portion extends along the width direction of the electrode lead battery cell. In claim 5,
The indentation part is smaller than the width of the accommodating part, the battery cell extending larger than the width of the electrode lead. In claim 1,
The electrode lead includes a positive electrode lead and a negative electrode lead,
The recessed portion is a battery cell located in each of the sealing portion through which the positive lead and the sealing portion through which the negative lead passes. In claim 7,
The positive lead and the negative lead are disposed opposite to each other on both sides of the battery case. In claim 1,
The battery case further includes a cover portion positioned symmetrically with the receiving portion with respect to the boundary line,
A battery cell that is bent based on the boundary line, wherein the accommodating part and the cover part face each other. In claim 9,
The battery case is bent based on the boundary line, the indentation portion and the battery cell to face each other with the cover portion. In claim 1,
The battery case is a battery cell made of a pouch-type case of a laminate sheet including a resin layer and a metal layer. A battery module comprising the battery cell according to claim 1 .

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