WO2016171522A1 - Secondary battery pack and vehicle comprising same - Google Patents

Abstract

The present invention relates to a secondary battery pack and a vehicle comprising the same. Specifically, provided is a secondary battery pack comprising: one or more battery cells; and one or more structures which cover at least a part of the battery cells and are electrically insulated from the battery cells, wherein at least a part of the structures comprises a substance having a resistivity three times or less than the resistivity of at least one substance constituting a positive electrode collector of the battery cells. As a structure covering a battery cell, the secondary battery pack, according to the present invention, uses a substance having the same level of resistivity as a positive electrode collector. Thus, if the structure is brought into contact with the positive electrode collector through collisional destruction of the secondary battery pack, the structure, instead of the positive electrode collector, performs the function of a conductive path through which an electric current can flow, and thus it is possible to prevent ignition resulting from contact of the positive electrode collector with a negative electrode active material. Furthermore, application of the secondary battery pack to a vehicle results in an effect of securing high stability.

Description

Secondary battery pack and vehicle including same

Cross Citation with Related Application (s)

This application claims the benefit of priority based on Korean Patent Application No. 10-2015-0056374 of April 22, 2015 and Korean Patent Application No. 10-2016-0049029 of April 22, 2016, and the documents of the Korean patent application All content disclosed in is included as part of this specification.

Technical Field

The present invention relates to a secondary battery pack and a vehicle including the same.

Easily applicable to various products and having a high energy density and other electrical characteristics, secondary batteries are not only portable devices but also universal electric vehicles (EVs) or hybrid vehicles (HVs) that are driven by electric driving sources. It is applied to.

The secondary battery is attracting attention as a new energy source for improving eco-friendliness and energy efficiency in that not only the primary advantage of drastically reducing the use of fossil fuels is generated but also no by-products are generated due to the use of energy.

The battery pack applied to the electric vehicle or the like typically has a structure including an assembly composed of a plurality of unit cells.

One of the most important issues that are recently emerging for such a secondary battery is securing safety. If the safety of the secondary battery is not secured, it may lead to an accident such as an electric shock, a fire, or an explosion, as well as damage to the secondary battery, which may cause human and property damage.

When the stability of the secondary battery is threatened, it may be penetrated by a sharp needle-like material or exploded during a safety test such as a penetration test of the secondary battery.

In order to prevent ignition against the conventional collision failure, the electrode assembly formed by winding a separator interposed between the first electrode plate and the second electrode plate and the first electrode plate and the second electrode plate, and the electrode assembly A can including a can, wherein the separator is formed of a material including ceramic, the polarity of the first electrode plate is opposite to the can, and the outermost part of the first electrode plate is formed of the second electrode plate. A lithium secondary battery disposed outside the outermost portion has been proposed.

However, the secondary battery having the above structure requires a new approach as the size and energy density increase, and there is a problem that it is difficult to secure fundamental safety even with the above method.

Accordingly, there is a need for the development of a secondary battery that fundamentally blocks the risk of explosion when the secondary battery is crashed and improves safety.

Prior literature

Republic of Korea Patent No. 10-0876268

The first technical problem to be solved of the present invention is to provide a secondary battery pack with improved safety from the risk of explosion.

The second technical problem to be solved of the present invention is to provide a vehicle including the secondary battery pack as a power source.

In order to solve the above problems, in one embodiment of the present invention

At least one battery cell and at least one structure surrounding at least a portion of the battery cell and electrically insulated from the battery cell, wherein at least a portion of the structure has a resistivity of at least one material constituting a positive electrode current collector of the battery cell; Provided is a secondary battery pack including a material having a resistivity of 3 times or less.

Specifically, in one embodiment of the present invention

A housing, at least one partition wall for spatially separating the interior of the housing, at least one electrode cell accommodated between the partition wall and the partition wall of the housing space, and an electrolyte solution contained in the housing,

The electrode cell includes a positive electrode including a positive electrode active material coated on a positive electrode current collector, a negative electrode including a negative electrode active material coated on a negative electrode current collector, and positioned between the positive electrode and the negative electrode to electrically separate the positive electrode and the negative electrode. And a separator for

At least a portion of at least one of the housing and the partition wall provides a secondary battery pack made of a material having a resistivity of 3 times or less than that of the cathode current collector material.

More specifically, in one embodiment of the present invention

A housing, at least one partition wall for spatially separating the interior of the housing, at least one electrode cell accommodated between the partition wall and the partition wall of the housing space, and an electrolyte solution contained in the housing,

The electrode cell includes a positive electrode including a positive electrode active material coated on a positive electrode current collector, a negative electrode including a negative electrode active material coated on a negative electrode current collector, and positioned between the positive electrode and the negative electrode to electrically separate the positive electrode and the negative electrode. And a separator for

At least a portion of the housing provides a secondary battery pack made of a material having a resistivity of 3 times or less than that of the positive electrode current collector constituent material.

In addition, the present invention provides a vehicle comprising a secondary battery pack as a power source.

Since the secondary battery pack according to the present invention uses a material having the same level of resistivity as that of the positive electrode current collector as a structure surrounding the battery cell, when the secondary battery pack collides and breaks and the structure contacts the positive electrode current collector, the structure Instead of the positive electrode current collector, it serves as a conductive path through which current can flow, thereby preventing ignition due to contact between the positive electrode current collector and the negative electrode active material. Furthermore, there is an effect of ensuring a high stability by applying the secondary battery pack to a vehicle.

1 is a schematic view showing an example of a secondary battery pack of the present invention.

2 is a schematic view showing an example of the battery cell of the present invention.

3 is a schematic diagram showing an example of (a) a secondary battery pack of the present invention, and (b) a schematic diagram showing an example of a case where a secondary battery pack is broken.

Explanation of Reference Numbers

1, 410: anode

2. 430: separator

3, 420: cathode

10: battery cell

20: bulkhead

30, 440: housing

100: secondary battery pack

Hereinafter, the present invention will be described in more detail to aid in understanding the present invention.

The terms or words used in this specification and claims are not to be construed as being limited to their ordinary or dictionary meanings, and the inventors may appropriately define the concept of terms in order to best describe their invention. It should be interpreted as meaning and concept corresponding to the technical idea of the present invention based on the principle that the present invention.

The terminology used herein is for the purpose of describing exemplary embodiments only and is not intended to be limiting of the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise.

As used herein, the terms "comprise", "comprise" or "have" are intended to indicate that there is a feature, number, step, component, or combination thereof, that is, one or more other features, It should be understood that it does not exclude in advance the possibility of the presence or addition of numbers, steps, components, or combinations thereof.

First, referring to FIG. 3A, a conventional secondary battery pack includes a positive electrode 410 including a positive electrode active material coated on a positive electrode current collector, and a negative electrode 420 including a negative electrode active material coated on a negative electrode current collector. And one or more electrode cells positioned between the positive electrode and the negative electrode and including a separator 430 for electrically separating the positive electrode and the negative electrode, and a housing 440 accommodating the battery cell. Charge and discharge are possible by the electrochemical reaction of the liver.

On the other hand, iron (9.68 µΩ · cm), which has a higher resistivity, is mainly used as a material for a housing or partition of a conventional secondary battery, compared to aluminum (2.73 µΩ · cm), which is mainly used as a cathode current collector. Therefore, as illustrated in FIG. 3B, when the secondary battery pack including the battery cell and the housing is destroyed, it may cause various heat generation and ignition.

The causes of the heat generation include ① contact between the positive electrode current collector and the negative electrode current collector, ② contact between the positive electrode current collector and the negative electrode active material, ③ contact between the positive electrode active material and the negative electrode current collector, and ④ contact between the positive electrode active material and the negative electrode active material. Among them, as much current flows into the positive electrode current collector, the contact between the positive electrode current collector and the negative electrode active material is very dangerous in terms of heat generation.

In order to prevent ignition of collision breakdown of such a secondary battery, a method such as using a separator including a conventional ceramic has been proposed. However, in the case of the above method, as the size of the secondary battery increases and the energy density increases, a new approach is additionally required, and it is difficult to secure fundamental safety.

Thus, in the present invention, in order to prevent the risk of high heat generation and ignition when the positive electrode current collector and the negative electrode active material contact when the secondary battery is destroyed, a current instead of the positive electrode current collector is formed in a structure such as a housing surrounding the battery cell. By applying a material that can act as a conductive path that can flow, to provide a secondary battery pack with improved stability.

Specifically, in one embodiment of the present invention

One or more battery cells and one or more structures surrounding at least a portion of the battery cells and electrically insulated from the battery cells,

At least a part of the structure provides a secondary battery pack including a material having a resistivity of 3 times or less with respect to the resistivity of at least one material constituting the cathode current collector.

Hereinafter, the present invention will be described in detail with reference to FIGS. 1 and 2 according to the embodiment, and the scope of the present invention is not limited by this range.

1, an embodiment of the present invention provides a secondary battery pack 100 including one or more battery cells 10 and one or more structures surrounding at least a portion of the battery cells and electrically insulated from the battery cells. do.

The battery cell 10 includes a positive electrode 1 including a positive electrode active material coated on a positive electrode current collector, a separator 2, a negative electrode 3 including a negative electrode active material coated on a negative electrode current collector, and an electrolyte (not shown). And the like, and may be charged and discharged by an electrochemical reaction between the components (see FIG. 2).

In this case, the positive electrode current collector may be made of aluminum, or at least one metal selected from the group consisting of copper, nickel, iron, stainless steel, and titanium on the aluminum.

In addition, the structure includes a housing 30 for receiving one or more battery cells 10; And a partition wall 20 separating the battery cell 10 and the battery cell 10; and at least one selected from the group consisting of the battery cell 10 and the battery cell 10. All of the structures inside the secondary battery pack surrounding a portion may be applicable.

At least a portion of the structure may be less than three times the resistivity of the material constituting the positive electrode current collector or at least one material coated on the positive electrode current collector, such that at least part of the structure may serve as a conductive path through which current may flow instead of the positive electrode current collector. Specifically, a material having a resistivity of 0.5 to 1 times can be used.

In this case, when the resistivity of the structure exceeds three times that of the positive electrode current collector constituent material, since the resistivity of the structure is too high compared to that of the positive electrode current collector, when the secondary battery pack is destroyed, the current of the positive electrode current collector is transferred to the structure. There is a problem that the heat generation, ignition of the battery pack is not delivered.

On the other hand, in the secondary battery pack of the present invention, at least a part of the structure is made of a material of 3 times or less, specifically, 0.5 to 1 times less than the positive electrode current collector constituent material, Compared with the structure having a higher electrical conductivity, it is possible to more easily bring the current of the positive electrode current collector, it is possible to implement an excellent secondary battery ignition prevention effect.

In the secondary battery pack of the present invention, at least a portion of the structure is at least one selected from the group consisting of silver, copper, gold, aluminum, tungsten, zinc, brass and nickel, specifically silver, copper, At least one material selected from the group consisting of gold and aluminum, or at least one material selected from the group consisting of silver, copper, gold, aluminum, tungsten, zinc, brass and nickel on a stainless steel surface, specifically silver May be composed of a stainless steel / coating layer by coating at least one material selected from the group consisting of copper, gold, and aluminum.

 As such, the structure consisting of the stainless steel / coating layer may reduce the risk of ignition by acting as a conductive path through which the current flows in place of the positive electrode current collector, in which the coating layer which first contacts the positive electrode current collector when the cell breaks down.

For example, the cathode current collector may use aluminum having a resistivity of 2.73 µΩ · cm, and the structure may include silver (1.62 µΩ · cm), copper (1.72 µΩ · cm), gold (2.4 µΩ · cm), and aluminum ( At least one material selected from the group consisting of 2.73 μΩ · cm), tungsten (5.5 μΩ · cm), zinc (5.9 μΩ · cm), brass (5 to 7 μΩcm) and nickel (7.24 μΩcm) May be included in at least one material selected from the group consisting of silver (1.62 μΩ · cm), copper (1.72 μΩ · cm), gold (2.4 μΩ · cm), and aluminum (2.73 μΩ · cm), It may include a form in which the material is coated on stainless steel.

Specifically, in the case where the structure is a housing, when silver having a resistivity of about 1/2 times as much as aluminum is included as a material of the housing, the silver may bring much current, thereby further increasing stability.

 In addition, the resistivity of the material included in at least a portion of the structure may be 1 to 8 μΩ · cm, specifically 1 to 3 μΩ · cm, but is not limited thereto, and may be 3 times or less according to the type of the positive electrode current collector. A material having a resistivity of may be appropriately selected and used.

If the positive electrode current collector is coated with a material other than a single composition, heat is generated in contact with the negative electrode active material because the coating material, which is the outermost part of the positive electrode current collector, causes a current to flow instead of the positive electrode current collector. In order to provide a conductive path that can be used, a material having a resistivity of 3 times or less with respect to the material of the positive electrode current collector, specifically, equivalent level, should be used as the material of the structure.

In this case, when another material is further coated on the positive electrode current collector, the structure may specifically use a material having a resistivity of 0.5 times to less than 1 times the resistivity of the material coated on the positive electrode current collector.

Specifically, in one embodiment of the present invention

A housing, at least one partition wall for spatially separating the interior of the housing, at least one electrode cell accommodated between the partition wall and the partition wall of the housing space, and an electrolyte solution contained in the housing,

The electrode cell includes a positive electrode including a positive electrode active material coated on a positive electrode current collector, a negative electrode including a negative electrode active material coated on a negative electrode current collector, and positioned between the positive electrode and the negative electrode to electrically separate the positive electrode and the negative electrode. And a separator for

At least a portion of the housing and the barrier rib provide a secondary battery pack made of a material having a resistivity of 3 times or less than that of the cathode current collector material.

More specifically, in one embodiment of the present invention

A housing, at least one partition wall for spatially separating the interior of the housing, at least one electrode cell accommodated between the partition wall and the partition wall of the housing space, and an electrolyte solution contained in the housing,

The electrode cell includes a positive electrode including a positive electrode active material coated on a positive electrode current collector, a negative electrode including a negative electrode active material coated on a negative electrode current collector, and positioned between the positive electrode and the negative electrode to electrically separate the positive electrode and the negative electrode. And a separator for

At least a portion of the housing provides a secondary battery pack made of a material having a resistivity of 3 times or less than that of the positive electrode current collector constituent material.

That is, the housing 30 may be manufactured by fixing and accommodating one or more battery cells 10 to a high capacity battery pack, and may protect the battery cells 10 from the outside. The housing 30 may be in the form of surrounding all of the one or more battery cells 10, or may be in the form of surrounding only a portion of the battery cell 10.

In addition, the partition wall 20 serves to prevent electrical contact between the battery cells 10 by separating the battery cells 10 and 10, and to dissipate heat generated when the battery is driven. The partition wall 20 may be positioned at the front portion between the battery cell 10 and the cell 10, and may be positioned only at an edge of the battery cell 10 to separate the battery cell 10 from the cell 10. It can also play a role.

In addition, since the housing and the partition wall are located closest to the battery cell 10, a conductive path for contacting the positive electrode current collector and bringing a current that can flow to the positive electrode current collector when the secondary battery pack 100 is destroyed is provided. Therefore, it is possible to prevent heat generation and ignition due to contact between the positive electrode current collector and the negative electrode active material.

In this case, at least a portion of the structure may be a portion facing the front portion of the battery cell 10. When the secondary battery is destroyed, only the front portion of the battery cell 10, which is the portion having the highest probability of contacting the positive electrode current collector (which occupies the largest area in the battery cell), is equivalent to the material of the positive electrode current collector. By using a coating structure, by using the components of the housing 30 or the partition wall 20 that is conventionally used as it can be manufactured by coating only the portion facing the front portion of the battery cell 10 with the material of the present invention and In this way, only a part of the coating is advantageous in terms of cost.

For example, there is a battery cell 10 in which the separator 2 is located between the sheet-shaped anode 1 and the cathode 3, and one battery cell anode 1 and the other battery cell cathode 3 face each other. In the secondary battery pack 100 in which the battery cells 10 are stacked and the stacked battery cells 10 are enclosed by the housing 30 or the partition wall 20, the battery cells 10 are accumulated. A portion of the housing 30 or the partition wall 20 positioned at the portion facing the front portion of the battery cell 10 positioned at the outermost side of the battery cell 10 may be used as a material having a level of resistivity equivalent to that of the positive electrode current collector.

As described above, in the present invention, in order to prevent the risk of high heat generation and ignition when the positive electrode current collector and the negative electrode active material contact when the secondary battery is destroyed, a structure such as a housing surrounding the battery cell is equivalent to the positive electrode current collector. By using the material having a level of resistivity, the structure may serve as a conductive path through which current can flow instead of the positive electrode current collector, thereby controlling the exothermicity, thereby improving safety.

On the other hand, the secondary battery pack according to an embodiment of the present invention may be a lithium secondary battery pack, a general lithium secondary battery cell may be configured to include a positive electrode, a negative electrode, a separator and a lithium salt-containing non-aqueous electrolyte.

In the battery cell, the positive electrode is prepared by, for example, applying a mixture of a positive electrode active material, a conductive material, and a binder onto a positive electrode current collector, followed by drying, and optionally, a filler is further added to the mixture.

The positive electrode 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 , Cu ₂ V ₂ O ₇ and the like; Ni-site type lithium nickel oxide represented by the formula LiNi _{1 - x} M _x O ₂ , wherein M is Co, Mn, Al, Cu, Fe, Mg, B or Ga, and x is 0.01 to 0.3; Formula LiMn _{2 - x} M _x O ₂ , wherein M is Co, Ni, Fe, Cr, Zn or Ta, x is 0.01 to 0.1, or Li ₂ Mn ₃ MO ₈ , wherein M is Fe, Co, Lithium manganese composite oxide represented by Ni, Cu or Zn); LiMn ₂ O _{4 in} which a part of Li in the formula is substituted with alkaline earth metal ions; Disulfide compounds; Fe ₂ (MoO ₄ ) ₃ and the like, but are not limited to these.

The conductive material is typically added in an amount of 1 to 30 wt% based on the total weight of the mixture including the positive electrode active material. Such a conductive material is not particularly limited as long as it has conductivity without causing chemical change in the battery, and examples thereof include graphite such as natural graphite and artificial graphite; Carbon blacks such as acetylene black, Ketjen black, channel black, furnace black, lamp black and thermal black; Conductive fibers such as carbon fibers and metal fibers; Metal powders such as carbon fluoride powder, aluminum powder and nickel powder; Conductive whiskeys 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 that assists the bonding of the active material and the conductive material to the current collector, and is generally added in an amount of 1 to 30 wt% based on the total weight of the mixture including the positive electrode active material. Examples of such binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene , Polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene-butadiene rubber, fluorine rubber, various copolymers, and the like.

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

The negative electrode is manufactured by coating and drying a negative electrode active material on a negative electrode current collector, and optionally, the components as described above may optionally be further included.

As said negative electrode active material, For example, carbon, such as hardly graphitized carbon and graphite type 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 ≦ 1; 1 ≦ y ≦ 3; 1 ≦ z ≦ 8); Lithium metal; Lithium alloys; Silicon-based alloys; Tin-based alloys; 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 metal oxides such as Bi ₂ O ₅ ; Conductive polymers such as polyacetylene; Li-Co-Ni-based materials and the like can be used.

The separator is 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 from 0.01 to 10 μm, and the thickness is generally from 5 to 300 μm. As such a separator, for example, olefin polymers such as chemical resistance and hydrophobic polypropylene; Sheets or non-woven fabrics made of glass fibers or polyethylene are used. When a solid electrolyte such as a polymer is used as the electrolyte, the solid electrolyte may also serve as a separator.

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

Examples of the non-aqueous liquid electrolyte include N-methyl-2-pyrrolidone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, gamma-butyrolactone and 1,2-dime Methoxy ethane, tetrahydroxy franc, 2-methyl tetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolon, formamide, dimethylformamide, dioxoron, acetonitrile, nitromethane, methyl formate, Methyl acetate, phosphate triester, trimethoxy methane, dioxoron derivatives, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate derivatives, tetrahydrofuran derivatives, ethers, methyl propionate Aprotic organic solvents, such as ethyl propionate, can be used.

Examples of the organic solid electrolytes include polyethylene derivatives, polyethylene oxide derivatives, polypropylene oxide derivatives, phosphate ester polymers, polyagitation lysine, polyester sulfides, polyvinyl alcohol, polyvinylidene fluoride, Polymers containing ionic dissociating 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, sulfates and the like of Li, such as Li ₄ SiO ₄ -LiI-LiOH, Li ₃ PO ₄ -Li ₂ S-SiS ₂ , and the like, may be used.

The lithium salt is a good material to be dissolved 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.

In addition, pyridine, triethyl phosphite, triethanolamine, cyclic ether, ethylenediamine, n-glyme, hexaphosphate triamide, for the purpose of improving charge / discharge characteristics, flame retardancy, etc. Nitrobenzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinones, N, N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrroles, 2-methoxy ethanol, aluminum trichloride, etc. It may be. In some cases, in order to impart nonflammability, a halogen-containing solvent such as carbon tetrachloride and ethylene trifluoride may be further included, or carbon dioxide gas may be further included to improve high temperature storage characteristics.

In addition, according to another embodiment of the present invention, a vehicle including the secondary battery pack 100 as a power source is provided.

The secondary battery pack 100 uses a material having a level of resistivity equivalent to that of a positive electrode current collector in a structure surrounding the battery cell 10, thereby allowing the secondary battery pack 100 having a large scale and high energy density to be used in a vehicle. Even if destroyed, the risk of explosion due to heat generation and ignition can be prevented.

In this case, the vehicle may be an electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily practice the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

Example

Example 1.

89% by weight of a mixture of LiCoO ₂ as a positive electrode active material, 8% by weight of carbon black as a conductive material, and 3% by weight of polyvinylidene fluoride (PVdF) as a binder were used as a solvent, N-methyl-2-pyrrolidone ( NMP) to prepare a positive electrode slurry. The positive electrode mixture slurry was applied to a thin film of aluminum (Al), which is a positive electrode current collector having a thickness of about 20 μm, and dried, followed by roll press to prepare a positive electrode.

Further, a negative electrode mixture slurry was prepared by adding 97 wt%, 2 wt%, and 1 wt% of graphite black as a negative electrode active material, PVdF as a binder, and carbon black as a conductive material, respectively, to NMP as a solvent. The negative electrode mixture slurry was applied to a thin copper (Cu) thin film, which was a negative electrode current collector having a thickness of 10 μm, and dried, followed by roll press to prepare a negative electrode.

An electrode assembly including the positive electrode, the negative electrode, and the polyolefin separator prepared as described above was inserted into a battery case, thereby manufacturing a battery cell.

Subsequently, the battery cell was accommodated in a housing made of aluminum (2.73 µΩ · cm) to manufacture a secondary battery pack.

Example 2.

A secondary battery pack was manufactured in the same manner as in Example 1, except that a housing made of silver (1.62 μΩ · cm) was used instead of the aluminum housing.

Example 3.

A secondary battery pack was manufactured in the same manner as in Example 1, except that a housing having a copper (1.72 μΩ · cm) coated on a stainless steel surface was used instead of the housing made of aluminum.

Comparative Example 1.

A secondary battery pack was manufactured in the same manner as in Example 1, except that a housing made of iron (9.68 μΩ · cm) was used instead of the aluminum housing.

Experimental Example

Experimental Example 1. Nail Penetration Test

The secondary battery packs prepared in Examples 1 to 3 and Comparative Example 1 were prepared in a fully charged state. Using a nail penetration tester, a nail of 3.0 mm in diameter (Experiment 1) and a nail of 3.0 mm in diameter (Experiment 2) were made in the center of the secondary battery packs prepared in Examples 1 to 3 and Comparative Example 1. Each penetrating experiment was performed. The penetration rate was 5 cm per second. Table 1 shows the results indicating the ignition.

Example 1 Example 2 Example 3 Comparative Example 1 Housing material aluminum silver Stainless steel / copper iron Experiment 1 Do not fire Do not fire Do not fire Fire Experiment 2 Fire Do not fire Do not fire Fire

As shown in Table 1, in the case of the pack of secondary batteries of Examples 2 and 3 including a housing made of a material having a lower resistivity than the secondary battery current collector material, a current may flow instead of the housing positive electrode current collector. It can be seen that the role of the pass does not ignite in both experiments 1 and 2.

On the other hand, in the case of the secondary battery pack of Comparative Example 1 including a housing made of iron having a higher resistivity than the secondary battery current collector material, it can be seen that both of Experiments 1 and 2 ignite.

Meanwhile, in the case of the secondary battery pack of Example 1 including a housing made of aluminum having the same resistivity as the secondary battery current collector material, the secondary battery pack of Example 1 using aluminum nails did not ignite, whereas the experiment using iron nail It can be seen that it ignites.

From these results, when aluminum is used as the positive electrode current collector, when it comes into contact with a nail made of aluminum having an equivalent resistivity by a penetration test, the nail may carry a current and may occur as the positive electrode current collector and the negative electrode active material contact each other. While the ignition does not occur, when contacted with a nail made of iron, since the iron current having high resistivity does not flow, it can be seen that ignition occurs by the positive electrode current collector and the negative electrode active material.

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 concepts of the present invention defined in the following claims are also provided. It belongs to the scope of the invention.

Claims (24)

One or more battery cells and one or more structures surrounding at least a portion of the battery cells and electrically insulated from the battery cells, At least a portion of the structure comprises a material having a resistivity of 3 times or less with respect to the resistivity of at least one material constituting the positive electrode current collector of the battery cell. The method according to claim 1, The positive electrode current collector is a secondary battery pack made of aluminum. The method according to claim 2, The positive electrode current collector is a secondary battery pack that is further coated with at least one metal selected from the group consisting of aluminum, copper, nickel, iron, stainless steel and titanium. The method according to claim 1, The structure is a secondary battery pack of at least one selected from the group consisting of a housing for accommodating one or more battery cells and a partition wall separating the battery cells and the battery cells. The method according to claim 1, At least a portion of the structure is a secondary battery pack that is a portion facing the front portion of the battery cell. The method according to claim 1, At least a portion of the structure is a secondary battery pack comprising a material having a resistivity of 0.5 times to 1 times with respect to the resistivity of at least one material constituting the positive electrode current collector of the battery cell. The method according to claim 1, The secondary battery pack of claim 1, wherein the resistivity of the material contained in at least a portion of the structure is 1 μΩ · cm to 8 μΩ · cm. The method according to claim 7, The resistivity of the material included in at least a portion of the structure is a secondary battery pack of 1 μΩ · cm to 3 μΩ · cm. The method according to claim 1, The material included in at least a portion of the structure is at least one secondary battery pack selected from the group consisting of silver, copper, gold, aluminum, tungsten, zinc, brass and nickel. The method according to claim 9, The material included in at least a portion of the structure is at least one secondary battery pack selected from the group consisting of silver, copper, gold and aluminum. The method according to claim 1, The material included in at least a portion of the structure is a secondary battery pack is coated on at least one material selected from the group consisting of silver, copper, gold, aluminum, tungsten, zinc, brass and nickel on stainless steel. The method according to claim 11, The material included in at least a portion of the structure is a secondary battery pack is coated on at least one material selected from the group consisting of silver, copper, gold and aluminum on stainless steel. Housings, At least one partition wall for spatially separating the inside of the housing; At least one electrode cell accommodated between the partition wall and the partition wall in the housing; An electrolyte contained in the housing, The electrode cell includes a positive electrode including a positive electrode active material coated on a positive electrode current collector, a negative electrode including a negative electrode active material coated on a negative electrode current collector, and positioned between the positive electrode and the negative electrode to electrically separate the positive electrode and the negative electrode. And a separator for At least a portion of at least one of the housing and the partition wall is formed of a material having a resistivity of 3 times or less of the resistivity of the positive electrode current collector constituent material. Housings, At least one partition wall for spatially separating the inside of the housing; At least one electrode cell accommodated between the partition wall and the partition wall in the housing; An electrolyte contained in the housing, The electrode cell includes a positive electrode including a positive electrode active material coated on a positive electrode current collector, a negative electrode including a negative electrode active material coated on a negative electrode current collector, and positioned between the positive electrode and the negative electrode to electrically separate the positive electrode and the negative electrode. And a separator for At least a portion of the housing is formed of a material having a resistivity of 3 times or less than that of the positive electrode current collector constituent material. The method according to claim 13 or 14, The positive electrode current collector is a secondary battery pack made of aluminum. The method according to claim 13 or 14, The positive electrode current collector is a secondary battery pack that is further coated with at least one metal selected from the group consisting of aluminum, copper, nickel, iron, stainless steel and titanium. The method according to claim 13 or 14, At least a portion of at least one of the housing and the partition wall includes a material having a resistivity of 0.5 to 1 times the resistivity of at least one material constituting the positive electrode current collector. The method according to claim 13 or 14, The secondary battery pack of claim 1, wherein the resistivity of the material included in at least a portion of the housing and the partition wall is 1 μΩ · cm to 8 μΩ · cm. The method according to claim 13 or 14, The secondary battery pack of claim 1, wherein the resistivity of the material included in at least a portion of the housing and the partition wall is 1 μΩ · cm to 3 μΩ · cm. The method according to claim 13 or 14, The material included in at least a portion of at least one of the housing and the partition wall is at least one or more selected from the group consisting of silver, copper, gold, aluminum, tungsten, zinc, brass and nickel. The method according to claim 13 or 14, The material included in at least a portion of at least one of the housing and the partition wall is at least one or more selected from the group consisting of silver, copper, gold and aluminum. The method according to claim 13 or 14, The material included in at least a portion of at least one of the housing and the partition wall is a secondary coated with at least one material selected from the group consisting of silver, copper, gold, aluminum, tungsten, zinc, brass and nickel on stainless steel. Battery pack. The method according to claim 13 or 14, The material included in at least a portion of at least one of the housing and the partition wall is coated on at least one material selected from the group consisting of silver, copper, gold and aluminum on a stainless steel. A vehicle comprising the secondary battery pack of claim 1 as a power source.

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