KR20170013809A - Battery Cell Having Recess Portion Formed at Portion of Electrode Tab - Google Patents

Abstract

The present invention provides a battery cell which can have increased capacity and which can be fabricated in various shapes. The battery cell according to the present invention comprises: an electrode assembly which comprises a cathode tab and an anode tab on at least one side edge thereof; a battery case which comprises a receiving unit configured to receive the battery assembly and a sealed surplus portion formed by thermally welding the edge in a state in which the electrode assembly has been accommodated in the receiving unit; and a cathode lead and an anode lead which protrude from the outside of the battery in a state in which the leads have been connected to the anode tab and the cathode lead, respectively. A portion of the electrode assembly, in which the cathode tab and the anode tab are located, has a recess directed toward the center of the electrode assembly. The cathode tab and the anode tab protrude from the side of the recess. A portion of the electrode assembly, which protrudes with respect to the recess, comes in direct contact with the inside of the battery case.

Description

[0001] The present invention relates to a battery cell having a recessed portion formed in an electrode tab region,

The present invention relates to a battery cell including a depressed portion formed in an electrode tab portion.

In recent years, the demand for environmentally friendly alternative energy sources has become an indispensable factor for the future, as the increase in the price of energy sources due to depletion of fossil fuels and the interest in environmental pollution are amplified. Various researches on power generation technologies such as nuclear power, solar power, wind power, and tidal power have been continuing, and electric power storage devices for more efficient use of such generated energy have also been attracting much attention.

Particularly, as technology development and demand for mobile devices are increasing, the demand for batteries as energy sources is rapidly increasing, and accordingly, a lot of researches on batteries that can meet various demands have been conducted.

Typically, in terms of the shape of a battery, there is a high demand for a prismatic secondary battery and a pouch-type secondary battery which can be applied to products such as mobile phones with a small thickness, and has advantages such as high energy density, discharge voltage, There is a high demand for lithium secondary batteries such as lithium ion batteries and lithium ion polymer batteries.

Also, the secondary battery is classified according to the structure of the electrode assembly having the positive electrode, the negative electrode, and the separator interposed between the positive electrode and the negative electrode. Typically, the long battery- A stacked (stacked) electrode assembly in which a plurality of positive electrodes and negative electrodes cut in a predetermined size unit are sequentially stacked with a separator interposed therebetween, the jelly-roll type (wound type) electrode assembly having a structure in which a separator is interposed; In recent years, in order to solve the problems of the jelly-roll type electrode assembly and the stack type electrode assembly, an electrode assembly having an advanced structure, which is a combination of the jelly-roll type and the stack type, A stack / folding type electrode having a structure in which unit cells stacked with a separator interposed between an anode and a cathode are sequentially wound while being placed on a separation film Developed body lip.

The secondary battery includes a cylindrical battery and a prismatic battery in which the electrode assembly is housed in a cylindrical or rectangular metal can according to the shape of the battery case, and a pouch type battery in which the electrode assembly is housed in a pouch-shaped case of an aluminum laminate sheet .

In particular, in recent years, a pouch-shaped battery having a structure in which a stacked or stacked / folded electrode assembly is embedded in a pouch-shaped battery case of an aluminum laminate sheet has attracted much attention due to low manufacturing cost, small weight, And its usage is gradually increasing.

FIG. 1 schematically shows a general structure of a typical conventional pouch-type secondary battery as an exploded perspective view.

1, the pouch-type secondary battery 100 includes an electrode assembly 130, electrode taps 131 and 132 extending from the electrode assembly 130, electrodes (electrodes) 131 and 132 welded to the electrode taps 131 and 132, Leads 141 and 142, and a battery case 120 that accommodates the electrode assembly 130. As shown in FIG.

The electrode assembly 130 is a power generation element in which an anode and a cathode are sequentially stacked with a separation membrane interposed therebetween, and has a stacked or stacked / folded structure. The electrode tabs 131 and 132 extend from the respective electrode plates of the electrode assembly 130 and the electrode leads 141 and 142 have a plurality of electrode tabs 131 and 132 extending from the respective electrode plates, And they are partially exposed to the outside of the battery case 120. [0051] An insulating film 150 is attached to a portion of the upper and lower surfaces of the electrode leads 141 and 142 in order to increase the degree of sealing with the battery case 120 and at the same time to secure an electrically insulated state.

The battery case 120 includes a case body 122 including a concave shaped storage portion 123 on which the electrode assembly 130 can be placed and a lid 121 integrally connected to the body 122 And the electrode assembly 130 is housed in the housing part 123 and the side parts 124 and the upper part 125, which are the contact parts, are joined to each other to complete the battery. The battery case 120 is made of an aluminum laminate structure of resin layer / metal foil layer / resin layer so that heat and pressure are applied to both side portions 124 and upper end portions 125 of the lid 121 and the body 122, The resin layers are mutually fused to form a bonded surplus portion. Both side portions 124 are in direct contact with the same resin layers of the upper and lower battery case 120, so that they can be uniformly sealed by melting. Since the electrode leads 141 and 142 protrude from the upper end portion 125 of the battery case 120 in consideration of the thickness of the electrode leads 141 and 142 and the material of the battery case 120, And the leads 141 and 142 are thermally fused with the insulating film 150 interposed therebetween.

2 is a schematic plan view schematically showing the structure of the pouch type secondary battery of FIG.

2, the electrode assembly 130 of the pouch-type secondary battery 100 is embedded in the receiving portion 123 of the battery case 120, and the electrode assembly 130 includes the electrode tabs 131 and 132 V-forming portions formed by the bending of the electrode tabs 131 and 132 are spaced from the upper end 125 of the battery case 120 by a predetermined distance.

Therefore, the remaining portion except for the V-forming portion is also spaced apart from the upper end 125 of the battery case 120, and such a spaced portion is left as an unnecessary space that is not utilized properly.

An insulating film 150 is interposed between the electrode leads 141 and 142 and the battery case 120 to seal the top end portion 125 of the electrode leads 141 and 142, Has a greater width than the sealing abutment 162 of the both side portions 124.

Therefore, the sealing extension 161 of the upper end portion 125 of the battery case 120 has a width larger than a width necessary for exhibiting a desired sealing force.

Accordingly, the wide width sealing pad 161 increases the overall size of the secondary battery 100, and has a problem that a space for mounting the device using the secondary battery 100 as a power source is limited There is a problem that the sealing space 161 of the upper end portion 125 of the battery case 120 having a width wider than the necessary width can not be utilized properly.

Therefore, there is a high need for a technique capable of fundamentally solving such problems.

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.

The inventors of the present application have conducted intensive research and various experiments and, as will be described later, include an indentation portion introduced into the center of the electrode assembly at a position where the positive electrode tab and the negative electrode tab of the electrode assembly are located, The remaining protrusions are brought into direct contact with the inner surface of the battery case, thereby making it possible to increase the capacity of the battery cell by utilizing the unnecessary seal-up space and the remaining space of the remaining portions except for the positive electrode tab portion and the negative electrode tab portion, And it is possible to manufacture the battery in a variety of shapes. Thus, it is possible to solve the problem due to the limitation of the mounting space of the battery cell and to realize the maximum capacity, and the present invention has been accomplished.

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

An electrode assembly including a positive electrode tab and a negative electrode tab on at least one side of the electrode assembly;

And a sealing surplus portion formed by thermally welding the outer periphery of the electrode assembly in a state where the electrode assembly is housed in the housing portion; And

A positive electrode lead and a negative electrode lead protruding from the outside of the battery case in a state of being connected to the positive electrode tab and the negative electrode tab of the electrode assembly;

, ≪ / RTI >

Wherein the positive electrode tab and the negative electrode tab protrude from the sides of the indentation portion, and the positive electrode tab and the negative electrode tab protrude from the sides of the indentation portion,

The protrusion of the electrode assembly protruding relatively to the indented portion may be in direct contact with the inner surface of the battery case.

Therefore, the protruding portion except for the indentation portion is directly brought into contact with the inner surface of the battery case, so that unnecessary sealing space and spacing space of remaining portions except for the positive electrode tab portion and the negative electrode tab portion are utilized, The capacity of the battery cell can be increased and the battery cell can be manufactured in a variety of shapes, thereby solving the problem due to the limitation of the mounting space of the battery cell and realizing the maximum capacity.

In one specific example, the positive electrode tab and the negative electrode tab may be of a structure that is positioned together on the same outer periphery of the same one side of the electrode assembly, but not limited thereto, It may be a structure in which each of them is located.

In addition, a structure in which an insulating film is attached to a portion of the battery case where the positive electrode lead and the negative electrode lead are located is sealed.

As described above, the positive electrode lead and the negative electrode lead protrude to the outside of the battery case in a state of being connected to the positive electrode tab and the negative electrode tab, respectively. Accordingly, some portions of the positive electrode lead and the negative electrode lead are sealed Located.

Since the positive electrode lead and the negative electrode lead are made of a material different from the battery case, the sealing of the positive electrode lead and the negative electrode lead and the battery case and the sealing of the battery case, The insulating film may be attached to the upper and lower surfaces of the positive electrode lead and the negative electrode lead in the negative electrode.

Meanwhile, the indentation depth of the indentation may be 3% to 20% of the length of the electrode assembly in the indentation direction in a plan view, and the indentation width may be 30% to 80% of the width of the electrode assembly.

When the indentation depth of the indented portion is too small beyond the above range, the effect of increasing the capacity of the battery cell is not so large. On the other hand, when the indentation depth of the indented portion is excessively out of the above range, And an unnecessary space may be increased in a portion where the negative electrode tab is located.

In addition, when the width of the depressed portion is excessively smaller than the above range, a space can not be secured such that the positive electrode tab and the negative electrode tab can be positioned in the depressed portion. On the contrary, If it is too large, the effect of increasing the capacity of the battery cell may not be so large.

In addition, the lengths of the positive electrode tab and the negative electrode tab may be 50% to 150% of the recessed depth of the recessed portion.

If the length of the positive electrode tab and the negative electrode tab is less than 50% with respect to the indentation depth of the indented portion, the connection portion between the positive electrode lead and the negative electrode lead can not be secured sufficiently. On the other hand, The V-forming portion formed by bending the positive electrode tab and the negative electrode tab becomes excessively large, and the space for positioning the V-forming portion may become insufficient.

In one specific example, in the outer periphery of the electrode assembly where the positive electrode tab and / or negative electrode tab is located, at least two protrusions are formed, and the protruded heights of the protrusions may all be the same or different from each other.

More specifically, the protrusion is a portion protruding from the outer periphery of the outer periphery of the electrode assembly where the positive electrode tab and the negative electrode tab are located, with the gap between the positive electrode tab and the negative electrode tab, Two or more portions may be selectively formed on the opposed portion and the portion opposed to the positive electrode tab with respect to the negative electrode tab.

At this time, the height of the two or more protrusions may be appropriately selected depending on the shape of the pack case to which the battery cell is applied, the mounting space of the device, or the like.

On the other hand, if the battery case has a structure in which a receiving portion capable of receiving the electrode assembly of the above-described structure is formed, the type thereof is not particularly limited. However, in order to more easily form the sealing surplus portion, And may be a pouch-shaped case of a laminate sheet including a ground layer and a metal layer.

The battery case may have a structure in which the inner circumferential surface of the accommodating portion corresponding to the depressed portion of the electrode assembly has a shape corresponding to a virtual outside circumference connecting the outer peripheries of the protruding portions of the electrode assembly.

Here, the term "virtual outside" refers to a virtual line connecting the outer peripheries of the protrusions when protruded heights of two or more protrusions are equal to or different from each other.

Therefore, the electrode assembly can be stably mounted to the battery case of the battery case regardless of the difference in the protruding height of the protrusions.

In one specific example, the shape of the battery case is not limited to a specific shape. In detail, the shape of the battery case may be circular, triangular, square, or polygonal in plan view, The shape of the device or the mounting space of the device.

Meanwhile, the sealing surplus portion of the battery case may have a structure in which the width of the indentation portion is larger than the width of the remaining portion in plan view.

Specifically, an electrode tab is located at a portion corresponding to the indentation portion of the electrode assembly, and the electrode lead is connected to the electrode tab to protrude to the outside of the battery case. Accordingly, the insulating film may be attached to the sealing portion of the battery case where the electrode lead is located, and the sealing surplus portion of the indentation portion to which the insulating film is attached may correspond to the width of the insulating film so as to exhibit a high sealing force. . ≪ / RTI >

Therefore, the sealing surplus portion of the battery case has a structure in which the width of the indentation portion is relatively large in plan view relative to the width of the remaining portion, and the positive lead and the negative electrode lead located in the portion corresponding to the indentation portion, A sealing force can be exerted.

In one specific example, the battery case may have a structure in which a sealing surplus portion at a corner where both sides adjacent to each other in the outer periphery meet is chamfered.

More specifically, the battery case may be bent in the direction of the side wall of the battery case accommodating portion to minimize the size, improve the sealing force in sealing the seal case, and mount the battery pack case to the device more easily.

In such a case, the outer periphery of the battery case may be deformed due to the bending due to the bending of the outer edge of the battery case. In this case, The overall manufacturing process of the cell may be delayed.

Therefore, the battery case may be chamfered at the corner portions of the outer periphery where both sides adjacent to each other meet, thereby preventing the problem.

The electrode assembly may include one or more positive electrodes and one or more negative electrodes in a state where the separator is interposed therebetween. In this case, May be sequentially stacked.

At this time, the portions corresponding to the indentation portions of the separation membranes interposed between the anode and the cathode are cut off, so that the electrode taps can be more easily interconnected without interference of the separation membrane.

In addition, since the portion corresponding to the indented portion of the separator is closely adhered to the inner surface of the indented portion by heat shrinkage, insulation of the electrode tab portion located in the indented portion is secured, or internal short-circuit due to external impact such as needle- , Safety can be improved.

In another specific example, the electrode assembly may have a structure in which unit cells of a laminated structure composed of an anode and a cathode, and a separator interposed between the anode and the cathode are sequentially wound by a separator sheet.

In this case, the separator sheet may have a structure in which a portion corresponding to the recessed portion is cut off.

More specifically, the separator sheet is positioned between the unit cells in the process of winding, and at this time, the positive electrode taps and the negative electrode tabs of the unit cells are connected to the electrode leads in a state of being connected to each other by welding or the like, By forming the cut-out portion of the separator sheet corresponding to the depressed portion, the electrode tabs can be connected more easily.

In addition, the separator sheet may have a structure in which a portion corresponding to the recessed portion is closely attached to the inner surface of the recessed portion by heat shrinkage.

More specifically, the separator sheet can be melted and shrunk by heat. In this process, a portion corresponding to the indentation portion is closely adhered to the inner surface of the indent portion by heat shrinkage, Or minimizing an internal short circuit due to an external impact such as needle piercing, safety can be improved.

In another specific example, the electrode assembly may have a structure in which unit cells of a stacked structure composed of an anode and a cathode, and a separator interposed between the anode and the cathode are laminated with an additional separator interposed therebetween.

That is, the electrode assembly has a structure in which a plurality of unit cells are stacked with an additional separator interposed therebetween.

At this time, the portions corresponding to the indentation portions of the separation membranes interposed between the anode and the cathode are cut off, so that the electrode taps can be more easily interconnected without interference of the separation membrane.

In addition, since the portion corresponding to the indented portion of the separator is closely adhered to the inner surface of the indented portion by heat shrinkage, insulation of the electrode tab portion located in the indented portion is secured, or internal short-circuit due to external impact such as needle- , Safety can be improved.

The battery cell may be a lithium secondary battery such as a lithium ion battery or a lithium ion polymer battery having advantages such as high energy density, discharge voltage, and output stability, although the type of the battery cell is not particularly limited. .

Generally, a lithium secondary battery is composed of a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte containing a lithium salt.

The positive electrode is prepared, for example, by coating a mixture of a positive electrode active material, a conductive material and a binder on a positive electrode current collector, and then drying the mixture. Optionally, a filler may be further added to the mixture.

The cathode active material may be a layered compound such as lithium cobalt oxide (LiCoO ₂ ), lithium nickel oxide (LiNiO ₂ ), or a compound substituted with one or more transition metals; Lithium manganese oxides such as Li _{1 + x} Mn _{2 -x} O ₄ (where x is 0 to 0.33), LiMnO ₃ , LiMn ₂ O ₃ , LiMnO ₂ and the like; Lithium copper oxide (Li ₂ CuO ₂ ); Vanadium oxides such as LiV ₃ O ₈ , LiFe ₃ O ₄ , V ₂ O ₅ and Cu ₂ V ₂ O ₇ ; A Ni-site type lithium nickel oxide expressed by the formula LiNi _1-x M _x O ₂ (where M = Co, Mn, Al, Cu, Fe, Mg, B or Ga and x = 0.01 to 0.3); Formula _{LiMn 2-x M x O 2} ( where, M = Co, Ni, Fe , Cr, and Zn, or Ta, x = 0.01 ~ 0.1 Im) or Li ₂ Mn ₃ MO ₈ (where, M = Fe, Co, Ni, Cu, or Zn); LiMn ₂ O _{4 in} which a part of Li in the formula is substituted with an alkaline earth metal ion; Disulfide compounds; Fe ₂ (MoO ₄ ) ₃ , and the like. However, the present invention is not limited to these.

The conductive material is usually added in an amount of 1 to 30% by weight based on the total weight of the mixture including the cathode active material. Such a conductive material is not particularly limited as long as it has electrical conductivity without causing chemical changes in the battery, for example, graphite such as natural graphite or artificial graphite; Carbon black such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and summer black; Conductive fibers such as carbon fiber and metal fiber; Metal powders such as carbon fluoride, aluminum, and nickel powder; Conductive whiskey such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives and the like can be used.

The binder is a component which assists in bonding of the active material and the conductive material and bonding to the current collector, and is usually added in an amount of 1 to 30% by weight based on the total weight of the mixture containing the cathode active material. Examples of such binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene , Polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butylene rubber, fluorine rubber, various copolymers and the like.

The filler is optionally used as a component for suppressing the expansion of the anode, and is not particularly limited as long as it is a fibrous material without causing a chemical change in the battery. Examples of the filler include olefin polymers such as polyethylene and polypropylene; Fibrous materials such as glass fibers and carbon fibers are used.

The negative electrode is manufactured by applying and drying a negative electrode active material on a negative electrode collector, and if necessary, the above-described components may be selectively included.

Examples of the negative electrode active material include carbon such as non-graphitized carbon and graphite carbon; _{Li x Fe 2 O 3 (0≤x≤1} ), Li x WO 2 (0≤x≤1), Sn x Me 1-x Me 'y O z (Me: Mn, Fe, Pb, Ge; Me' : Metal complex oxides such as Al, B, P, Si, Group 1, Group 2, Group 3 elements of the periodic table, Halogen, 0 < x &lt; Lithium metal; Lithium alloy; Silicon-based alloys; Tin alloy; _{SnO, SnO 2, PbO, PbO} 2, Pb 2 O 3, Pb 3 O 4, Sb 2 O 3, Sb 2 O 4, Sb 2 O 5, GeO, GeO 2, Bi 2 O 3, Bi 2 O 4, and Bi ₂ O ₅ ; Conductive polymers such as polyacetylene; Li-Co-Ni-based materials and the like can be used.

The separation membrane and the separation film are interposed between the anode and the cathode, and an insulating thin film having high ion permeability and mechanical strength is used. The pore diameter of the separator is generally 0.01 to 10 mu m, and the thickness is generally 5 to 130 mu m. Such separation membranes include, for example, olefinic polymers such as polypropylene, which are chemically resistant and hydrophobic; A sheet or nonwoven fabric made of glass fiber, polyethylene or the like is used. When a solid electrolyte such as a polymer is used as an electrolyte, the solid electrolyte may also serve as a separation membrane.

Further, in one specific example, in order to improve the safety of the battery, the separation membrane and / or the separation film may be an organic / inorganic composite porous SRS (Safety-Reinforcing Separators) separation membrane.

The SRS separator is manufactured by using inorganic particles and a binder polymer on the polyolefin-based separator substrate as an active layer component. In addition to the pore structure contained in the separator substrate itself, the SRS separator is formed by interstitial volume between inorganic particles And has a uniform pore structure.

The use of such an organic / inorganic composite porous separator has the advantage of suppressing an increase in thickness of the cell due to swelling at the time of chemical conversion compared with the case of using a conventional separator, When a gelable polymer is used when liquid electrolyte is impregnated, it can also be used as an electrolyte.

In addition, the organic / inorganic composite porous separator can exhibit excellent adhesion characteristics by controlling the contents of the inorganic particles and the binder polymer in the separator, so that the cell assembly process can be easily performed.

The inorganic particles are not particularly limited as long as they are electrochemically stable. That is, the inorganic particles usable in the present invention are not particularly limited as long as the oxidation and / or reduction reaction does not occur in the operating voltage range of the applied battery (for example, 0 to 5 V based on Li / Li +). Particularly, when inorganic particles having an ion-transporting ability are used, the ion conductivity in the electrochemical device can be increased and the performance can be improved. Therefore, it is preferable that the ionic conductivity is as high as possible. In addition, when the inorganic particles have a high density, it is difficult to disperse the particles at the time of coating, and there is a problem of an increase in weight during the production of the battery. In the case of an inorganic substance having a high dielectric constant, dissociation of an electrolyte salt, for example, a lithium salt, in the liquid electrolyte also contributes to increase ionic conductivity of the electrolyte.

The nonaqueous electrolyte solution containing a lithium salt is composed of a polar organic electrolyte and a lithium salt. As the electrolytic solution, a non-aqueous liquid electrolytic solution, an organic solid electrolyte, an inorganic solid electrolyte and the like are used.

Examples of the nonaqueous liquid electrolytic solution include N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, gamma -Butyrolactone, 1,2-dimethoxyethane, tetrahydroxyfuran, 2-methyltetrahydrofuran, dimethylsulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane , Acetonitrile, nitromethane, methyl formate, methyl acetate, triester phosphate, trimethoxymethane, dioxolane derivatives, sulfolane, methylsulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate Nonionic organic solvents such as tetrahydrofuran derivatives, ethers, methyl pyrophosphate, ethyl propionate and the like can be used.

Examples of the organic solid electrolyte include a polymer electrolyte such as a polyethylene derivative, a polyethylene oxide derivative, a polypropylene oxide derivative, a phosphate ester polymer, an agitation lysine, a polyester sulfide, a polyvinyl alcohol, a polyvinylidene fluoride, Polymers containing ionic dissociation groups, and the like can be used.

Examples of the inorganic solid electrolyte include Li ₃ N, LiI, Li ₅ NI ₂ , Li ₃ N-LiI-LiOH, LiSiO ₄ , LiSiO ₄ -LiI-LiOH, Li ₂ SiS ₃ , Li ₄ SiO ₄ , Nitrides, halides and sulfates of Li such as Li ₄ SiO ₄ -LiI-LiOH and Li ₃ PO ₄ -Li ₂ S-SiS ₂ can be used.

The lithium salt is a material that is readily soluble in the non-aqueous electrolyte, for example, LiCl, LiBr, LiI, LiClO 4, LiBF 4, LiB 10 Cl 10, LiPF 6, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF _{6, LiSbF 6, LiAlCl 4,} CH 3 SO 3 Li, CF 3 SO 3 Li, (CF 3 SO 2) 2 NLi, chloroborane lithium, lower aliphatic carboxylic acid lithium, lithium tetraphenyl borate and imide have.

For the purpose of improving the charge-discharge characteristics and the flame retardancy, the non-aqueous liquid electrolyte may contain, for example, pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylenediamine, glyme, N, N-substituted imidazolidine, ethylene glycol dialkyl ether, ammonium salt, pyrrole, 2-methoxyethanol, aluminum trichloride and the like are added It is possible. In some cases, a halogen-containing solvent such as carbon tetrachloride or ethylene trifluoride may be further added to impart nonflammability, or a carbon dioxide gas may be further added to improve high-temperature storage characteristics.

The present invention also provides a battery pack including the battery cell and a device including the battery pack as a power source, wherein the device is used for a mobile phone, a tablet computer, a notebook computer, a power tool, a wearable electronic device, An electric vehicle, a plug-in hybrid electric vehicle, and a power storage device.

Since the devices are well known in the art, a detailed description thereof will be omitted herein.

As described above, the battery cell according to the present invention includes a depressed portion in which the positive electrode tab and the negative electrode tab of the electrode assembly are positioned, and the remaining protruded portion is formed on the inner surface of the battery case It is possible to increase the capacity of the battery cell by utilizing the unnecessary sealing space and the spacing space of the remaining portions except for the positive electrode tab portion and the negative electrode tab portion without increasing the overall size of the battery cell, It is possible to solve the problem caused by the limitation of the space for mounting the battery cells and to realize the maximum capacity.

1 is an exploded perspective view of a general structure of a conventional pouch type secondary battery;
FIG. 2 is a plan view schematically showing the structure of the pouch type secondary battery of FIG. 1; FIG.
3 is a schematic view schematically showing the structure of a battery cell according to one embodiment of the present invention;
4 is a schematic view schematically showing the structure of a battery cell according to another embodiment of the present invention;
5 is a schematic view showing a structure in which the battery case of the battery cell of Figs. 3 and 4 is deformed; Fig.
6 to 9 are schematic views schematically showing the structure of a battery cell according to another embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to the drawings according to the embodiments of the present invention, but the scope of the present invention is not limited thereto.

3 is a schematic view schematically showing the structure of a battery cell according to an embodiment of the present invention.

3, the battery cell 300 has a structure in which an electrode assembly is housed in the housing part 321 of the battery case 320. The outer periphery of the battery case 320 is thermally fused to form a sealing surplus part .

The electrode assembly 310 includes a positive electrode tab 311 and a negative electrode tab 311 on the outer circumference of one side thereof and a negative electrode tab 311 and a negative electrode tab 312, And the positive electrode tab 311 and the negative electrode tab 312 protrude from the side of the depressed portion 341. As shown in FIG.

Two protrusions 342 and 343 are formed on both sides of the recessed portion 341 with respect to the recessed portion 341 as a reference.

The indentation depth 364 of the indentation 341 is about 15% of the length 365 of the electrode assembly 310 in the indentation direction.

The indentation 341 is spaced apart from the inner surface of the battery case 320 by a predetermined distance so that the V-forming portions formed by the positive electrode tab 311 and the negative electrode tab 312 can be located, 342, and 343 are in direct contact with the inner surface of the battery case 320.

The positive electrode tab 311 and the negative electrode tab 312 are connected to the positive electrode lead 331 and the negative electrode lead 332 in the indentation portion 341 and the positive electrode lead 331 and the negative electrode lead 332 are connected to the battery case 320, respectively.

An insulating film 350 is attached to the sealing portion of the battery case 320 where the positive electrode lead 331 and the negative electrode lead 332 are located.

Therefore, the width 363 of the sealing surplus portion of the depressed portion 341 is relatively large compared to the widths 361 and 362 of the sealing surplus portion of the remaining portion.

Due to the above structure, the battery cell 300 utilizes the sealing space of the remaining portion except for the portion where the positive electrode lead 331 and the negative electrode lead 332 are located, Can be increased.

4 is a schematic view schematically showing the structure of a battery cell according to another embodiment of the present invention.

4, the battery cell 400 has a structure in which the projected heights 464a and 464b of the protrusions 442 and 443 of the electrode assembly 410 are different from each other, 300 of FIG. 3).

Fig. 5 is a schematic view schematically showing a structure in which the battery case of the battery cell of Figs. 3 and 4 is deformed.

Referring to FIG. 5, the battery cases 320 and 420 are connected to an imaginary outer periphery 344 where the inner circumferential surfaces of the receiving portions 321 and 421 corresponding to the indented portions of the electrode assemblies interconnect the outer peripheries of the protrusions of the electrode assembly, respectively. , And 444, respectively.

Therefore, the electrode assembly can be stably mounted on the receiving portions 321 and 421 of the battery cases 320 and 420, and the electrode assembly can be stably mounted on the receiving portions 321 and 421 of the battery cases 320 and 420 And the outer circumferences of the battery cases 320 and 420 are thermally fused to form the sealing residues 360 and 460 so that the outer circumferential surfaces of the battery cases 320 and 420 are thermally fused. do.

The battery cases 320 and 420 are chamfered at the edge portions 360 and 460 at chamfered portions 322 and 422 so that the deformation of the shape of the corner portion caused by the bending of the seal ingots 360 and 460 Can be prevented.

6 to 9 are schematic views schematically showing the structure of a battery cell according to another embodiment of the present invention.

6, the battery cell 600 has a structure in which a depressed portion 641 is introduced in a streamlined manner toward the center of the electrode assembly 610, A negative electrode tab 611 and a negative electrode tab 612 protrude respectively.

The remaining structure of the battery cell 600 except for the structure of the indent 641 is the same as that of the battery cell 300 of FIG. 3 (detailed description thereof will be omitted).

7, the battery cell 700 has a structure in which the indentation 741 is introduced toward the center of the electrode assembly 710, and the inner side 713, 714 of the indent 741 is connected to the positive electrode A tab 611 and a negative electrode tab 612 protrude respectively.

The remaining structure of the battery cell 700 except for the structure of the depressed portion 741 is the same as that of the battery cell 300 of FIG. 3 (detailed description thereof will be omitted).

Referring to FIG. 8, the battery cell 800 has a structure in which two indentations 841 and 842 are introduced toward the center of the electrode assembly 810, A negative electrode tab 811 and a negative electrode tab 812 are respectively protruded.

A protrusion 843 relatively protruding from the indentations 841 and 842 is formed between the indentations 841 and 842.

The remaining structure of the battery cell 900 excluding the structures of the indentations 841 and 842 and the protrusion 843 is the same as that of the battery cell 300 of FIG. 3 (detailed description thereof will be omitted).

9, the battery cell 900 has a structure in which two indentations 941 and 942 are introduced toward the center of the electrode assembly 910, and the positive electrode tabs 941 and 942 are formed from the sides of the indentations 941 and 942, A negative electrode tab 911 and a negative electrode tab 912 are respectively protruded.

Three protrusions 943, 944 and 945 relatively protruding from the indentations 941 and 942 are formed between the indentations 941 and 942 and outside the indentations.

The remaining structure of the battery cell 900 excluding the structures of the indentations 941 and 942 and the protrusions 943, 944 and 945 is the same as that of the battery cell 300 of FIG. 3 Is omitted.

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)

An electrode assembly including a positive electrode tab and a negative electrode tab on at least one side of the electrode assembly;
And a sealing surplus portion formed by thermally welding the outer periphery of the electrode assembly in a state where the electrode assembly is housed in the housing portion; And
A positive electrode lead and a negative electrode lead protruding from the outside of the battery case in a state of being connected to the positive electrode tab and the negative electrode tab of the electrode assembly;
, &Lt; / RTI &gt;
Wherein the positive electrode tab and the negative electrode tab protrude from the sides of the indentation portion, and the positive electrode tab and the negative electrode tab protrude from the sides of the indentation portion,
Wherein protrusions of the electrode assembly protruding relative to the indented portion are in direct contact with the inner surface of the battery case. The battery cell according to claim 1, wherein the positive electrode tab and the negative electrode tab are co-located around the same outer periphery of the electrode assembly. The battery cell according to claim 1, wherein the positive electrode tab and the negative electrode tab are located at different outer peripheries of the electrode assembly. The battery cell according to claim 1, wherein an insulating film is attached to the sealing portion of the battery case where the positive electrode lead and the negative electrode lead are located. [3] The method of claim 1, wherein the indentation depth of the indent is about 3% to 20% of the length of the electrode assembly in the indentation direction in a plan view, and the width of the indent is about 30% to 80% . The battery cell according to claim 1, wherein the length of the positive electrode tab and the negative electrode tab is 50% to 150% of the depression depth of the indent. The battery cell according to claim 1, wherein at least two protrusions are formed on the outer periphery of the electrode assembly where the positive electrode tab and / or negative electrode tab is located, and the protruded heights of the protrusions are all the same. The battery cell according to claim 1, wherein at least two protrusions are formed at the outer periphery of the electrode assembly where the positive electrode tab and / or the negative electrode tab is located, and the protruded heights of the protrusions are different from each other. The battery cell according to claim 1, wherein the battery case is a pouch-shaped case of a laminate sheet including a resin layer and a metal layer. The battery case according to claim 1, wherein the battery case has a shape corresponding to an imaginary outer periphery where an inner circumferential surface of a receiving portion corresponding to a depressed portion of the electrode assembly interconnects outer peripheries of protrusions of the electrode assembly Cell. The battery cell according to claim 1, wherein the battery case has a circular, triangular, square, or polygonal shape in plan view. The battery cell according to claim 1, wherein the sealing surplus portion of the battery case is planar and the width of the indented portion is relatively larger than the width of the remaining portion. The battery cell according to claim 1, wherein the battery case has chamfered surplus portions at corners where both sides adjacent to each other meet in the outer periphery. The battery cell according to claim 1, wherein the electrode assembly has a structure in which at least one anode and at least one cathode are sequentially stacked with a separation membrane interposed therebetween. The battery cell according to claim 1, wherein the electrode assembly has a structure in which unit cells of a laminated structure composed of an anode and a cathode, and a separator interposed between the anode and the cathode are sequentially wound by a separator sheet. . The battery cell according to claim 15, wherein the separator sheet has a portion corresponding to the indentation portion cut off. The battery cell according to claim 15, wherein a portion of the separator sheet corresponding to the recessed portion is in close contact with the inner surface of the recessed portion by heat shrinkage. The battery according to claim 1, wherein the electrode assembly has a structure in which unit cells of a laminated structure composed of an anode and a cathode, and a separator interposed between the anode and the cathode are stacked with an additional separator interposed therebetween Cell. The battery cell according to claim 1, wherein the battery cell is a lithium secondary battery. A battery pack comprising the battery cell according to claim 1. 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 the group consisting of a cell phone, a tablet computer, a notebook computer, a power tool, a wearable electronic appliance, an electric vehicle, a hybrid electric vehicle, a plug- . &Lt; / RTI &gt;

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