KR20160116109A - Anode active material, method of fabricating the same, and lithium secondary battery comprising the same - Google Patents

Abstract

Provided is a manufacturing method of a negative electrode active material. The manufacturing method of a negative electrode active material comprises the following steps of: manufacturing a precursor structure which has a shape of a hexagonal column and contains titanium; and manufacturing a porous structure which has a shape of a hexagonal column and includes lithium titanium oxide by mixing lithium salt to the precursor structure, and heat-treating the resultant product.

Description

[0001] The present invention relates to an anode active material, a method of manufacturing the same, and an anode active material including the lithium secondary battery,

The present invention relates to a negative electrode active material, a method for producing the same, and a lithium secondary battery including the same, and more particularly, to a negative electrode active material including a hexagonal columnar porous structure containing lithium titanium oxide, The present invention relates to a lithium secondary battery including a lithium secondary battery.

With the development of portable mobile electronic devices such as smart phones, MP3 players, and tablet PCs and electric vehicles, the demand for lithium secondary batteries capable of storing electric energy has increased explosively.

Generally, carbon-based materials such as artificial graphite, natural graphite, and hard carbon are used as a cathode of a lithium secondary battery. It is difficult to use a graphite negative electrode lithium secondary battery for applications requiring high capacity secondary batteries such as next-generation mobile communication devices and electric vehicles with the theoretical limit of carbon-based materials (about 372 mAh / g). Accordingly, in order to overcome the theoretical limitations of existing graphite anode materials, various anode materials applicable to lithium secondary batteries are under development.

For example, in Korean Patent Laid-Open Publication No. 10-2014-0062202 (Application No. 10-2012-0128525, Applicant: Inha University Industry-Academy Collaboration Group), in order to provide a lithium secondary battery having excellent capacity and reversibility and having a stable cycle life, An elemental sulfur is introduced into graphene oxide (GO) to prepare a graphene nanosheet in which graphene oxide and sulfur are mixed at a weight ratio of 1: 0.01 to 1:10, Is used as a negative electrode material of a lithium secondary battery.

Korean Patent Publication No. 10-2014-0062202

Disclosure of Invention Technical Problem [8] The present invention provides a high-reliability anode active material, a method of manufacturing the same, and a lithium secondary battery including the same.

Another object of the present invention is to provide a lithium secondary battery having improved charging / discharging efficiency.

Another object of the present invention is to provide a lithium secondary battery having an increased usable life.

It is another object of the present invention to provide a lithium secondary battery having improved stability.

The technical problem to be solved by the present invention is not limited to the above.

According to an aspect of the present invention, there is provided a method for manufacturing a negative electrode active material.

According to one embodiment, the method for manufacturing the negative electrode active material comprises the steps of: preparing a hexagonal pillar-shaped precursor structure containing titanium; mixing and heat-treating the lithium salt to the precursor structure to form lithium titanium oxide; The method comprising the steps of: forming a porous structure in the form of a hexagonal column including the porous structure.

According to one embodiment, the porous structure may have a higher pore level than the precursor structure.

According to an embodiment, the step of preparing the precursor structure may include preparing a first mixed liquid in which oxalic acid and sodium dodecylbenzenesulfonate (SDBS) are mixed, and mixing the second mixed liquid containing titanium with the first mixed liquid And the like.

According to an embodiment, the method of manufacturing the negative active material may further include a step of heat-treating the first mixed solution before adding the second mixed solution to the first mixed solution.

According to one embodiment, the step of preparing the porous structure includes the steps of: preparing a source solution by dispersing the precursor structure and a lithium salt in a solvent; heat-treating the source solution to produce the porous structure; Separating the porous structure from the source solution, and washing and drying the porous structure.

According to one embodiment, the lithium salt and the precursor structure may be mixed in a weight ratio of 4: 5.

In order to solve the above technical problems, the present invention provides a negative electrode active material.

According to one embodiment, the negative electrode active material may include a porous structure including lithium titanium oxide and having a hexagonal pillar shape.

According to one embodiment, the porous structure may be partitioned into a plurality of particles and defining pores between the plurality of particles.

According to one embodiment, the porous structure is made from a precursor structure comprising titanium oxide and having a hexagonal columnar shape, and the porous structure may have a higher surface area than the precursor structure.

In order to solve the above technical problems, the present invention provides a lithium secondary battery.

According to one embodiment, the lithium secondary battery may include a negative electrode including a negative electrode active material according to the above-described embodiment, an opposite electrode to the negative electrode, and an electrolyte and a separator between the negative electrode and the positive electrode.

According to an embodiment of the present invention, there is provided an anode active material including a hexagonal columnar porous structure containing lithium titanium oxide by mixing a lithium salt with a hexagonal columnar precursor structure containing titanium and heat-treating the lithium salt.

The charge / discharge characteristics and capacity characteristics of the lithium secondary battery can be improved by the negative electrode active material including the porous structure having a hexagonal columnar shape.

1 is a view for explaining a method of manufacturing an anode active material according to an embodiment of the present invention.
2 is a view showing a porous structure having a hexagonal column shape according to an embodiment of the present invention.
3A is a SEM photograph of a precursor structure according to an embodiment of the present invention.
3B is a SEM photograph of a porous structure according to an embodiment of the present invention.
4 is an XRD graph of a porous structure made according to an embodiment of the present invention.
5 is a view illustrating a lithium secondary battery including a porous structure according to an embodiment of the present invention.
6 is a graph illustrating a discharge capacity characteristic of a lithium secondary battery including a porous structure according to an embodiment of the present invention.
7 is a block diagram of an electric vehicle according to an embodiment of the present invention.
8 is a perspective view of an electric vehicle according to an embodiment of the present invention.
9 is a view for explaining a battery pack according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the technical spirit of the present invention is not limited to the embodiments described herein but may be embodied in other forms. Rather, the embodiments disclosed herein are provided so that the disclosure can be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

In this specification, when an element is referred to as being on another element, it may be directly formed on another element, or a third element may be interposed therebetween. Further, in the drawings, the thicknesses of the films and regions are exaggerated for an effective explanation of the technical content.

Also, while the terms first, second, third, etc. in the various embodiments of the present disclosure are used to describe various components, these components should not be limited by these terms. These terms have only been used to distinguish one component from another. Thus, what is referred to as a first component in any one embodiment may be referred to as a second component in another embodiment. Each embodiment described and exemplified herein also includes its complementary embodiment. Also, in this specification, 'and / or' are used to include at least one of the front and rear components.

The singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise. It is also to be understood that the terms such as " comprises "or" having "are intended to specify the presence of stated features, integers, Should not be understood to exclude the presence or addition of one or more other elements, elements, or combinations thereof. Also, in this specification, the term "connection " is used to include both indirectly connecting and directly connecting a plurality of components.

In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

1 is a view for explaining a method of manufacturing an anode active material according to an embodiment of the present invention.

Referring to FIG. 1, a precursor structure 100 is prepared. The precursor structure 100 may comprise titanium. For example, the precursor structure 100 may be formed of Hydroxyl Titanium Oxalate.

The step of preparing the precursor structure 100 may include preparing a first mixed solution containing oxalic acid and sodium dodecylbenzenesulfonate (SDBS), heat treating the first mixed solution, A step of adding the precursor structure 100 to the heat-treated first mixed solution, the first and second mixed solutions reacting to produce the hexagonal pillar-shaped precursor structure 100, the first and second precursor structures 100, Separating them from the mixed liquors, and washing and drying the precursor structure 100.

The oxalic acid contained in the first mixed liquid may have a structure represented by the following Formula 1, and SDBS contained in the first mixed liquid may have a structure represented by Formula 2 below.

≪ Formula 1 >

(2)

According to one embodiment, the first mixed solution may be a mixed solution of DI water and ethanol added with oxalic acid and SDBS. The amount of oxalic acid added to the ultrapure water may be greater than the amount of SDBS added to the ultrapure water.

The heat-treated first mixed liquid may have a first temperature. For example, the first temperature may be 90 < 0 > C. The first mixed solution may be stirred and heat-treated under reflux.

According to one embodiment, the second mixed liquid may be added to the first mixed liquid having the first temperature by being divided and heat-treated at a time interval. According to one embodiment, the second mixed solution may include titanium butoxide (TBT) and acetic acid added to ethanol.

The first mixed liquid and the second mixed liquid are reacted at a second temperature for a reference time to form the hexagonal column-shaped precursor structure. According to an embodiment, the second temperature may be substantially equal to a first temperature (e.g., 90 ° C) that is a heat treatment temperature of the first mixed liquid.

According to one embodiment, the hexagonal column-shaped precursor structure is separated using centrifugation, washed with ultrapure water and ethanol, and then dried in a vacuum oven at 80 DEG C for 2 hours.

The precursor structure and the lithium salt (for example, LiOH) may be mixed and heat-treated to prepare a porous structure 200. The porous structure 200 may include lithium titanium oxide. For example, the porous structure 200 may comprise Li ₄ Ti ₅ O ₁₂ , and / or Li ₂ TiO ₃ . According to one embodiment, the main component of the porous structure 200 may be Li ₄ Ti ₅ O ₁₂ , and the subcomponent may be Li ₂ TiO ₃ . Alternatively, according to another embodiment, the porous structure 200 may further comprise Anatase TiO ₂ and / or Rutile TiO ₂ in addition to Li ₄ Ti ₅ O ₁₂ and Li ₂ TiO ₃ .

According to one embodiment, the lithium salt and the precursor structure 100 may be mixed substantially in a weight ratio of 4: 5. Accordingly, the Li ₄ Ti ₅ O ₁₂ content of the porous structure 200 produced by reacting the lithium salt and the precursor structure 100 may have a maximum value. Accordingly, the charge / discharge characteristics and the capacity characteristics of the lithium secondary battery manufactured using the negative electrode active material having the porous structure 200 can be improved.

The porous structure 200 may include a plurality of pores therein. In other words, the porous structure 200 is divided into a plurality of particles, and the plurality of pores may be defined between the plurality of particles. The porous structure 200 may be formed by aggregating the plurality of particles, but the porous structure 200 may be manufactured by a top down method instead of a bottom up method. In other words, unlike a bottom up method in which a plurality of particles are aggregated to form a structure, the porous structure 200 forms the plurality of pores therein while the precursor structure 100 reacts with the lithium salt (Top down method).

The porosity level of the porous structure 200 may be higher than the porosity level of the precursor structure 100. In other words, a greater number of pores may be present in the porous structure 200 than the precursor structure 100. Therefore, the surface area of the porous structure 200 may be wider than the surface area of the precursor structure 100.

The step of preparing the porous structure 200 may include preparing a source solution by dispersing the precursor structure 100 and a lithium salt in a solvent, heat-treating the source solution to produce the porous structure 200, Separating the porous structure 200 from the source solution, and washing and drying the porous structure 200. For example, the precursor structure 100 and the lithium salt may be dispersed in DI water to form the source solution, the source solution may be heat treated at 180 < 0 > C for 6 hours, Separated by centrifugation, dried using DI water and ethanol, and then dried at 70 ° C.

According to an embodiment of the present invention, the porous structure 200 including the lithium titanium oxide retaining a hexagonal pillar shape is manufactured using the hexagonal pillar-shaped precursor structure 100 and the lithium salt . By the hexagonal column shape of the porous structure 200, the charge / discharge characteristics and the capacity characteristics of the lithium secondary battery manufactured using the negative electrode active material including the porous structure 200 can be improved.

2, a hexagonal column shape of the porous structure 200 according to an embodiment of the present invention will be described in more detail.

2 is a view showing a porous structure having a hexagonal column shape according to an embodiment of the present invention.

Referring to FIG. 2, the hexagonal column shape of the porous structure 200 includes a hexagonal bottom surface, a hexagonal top surface, and six side surfaces .

The lower surface and the upper surface of the hexagonal column shape may be parallel to a first direction (x-axis direction in Fig. 2) and a second direction (y-axis direction in Fig. 2) perpendicular to the first direction. The lower surface and the upper surface of the hexagonal column shape have substantially the same area and may have substantially the same shape.

The upper surface and the lower surface may each include two long sides and four short sides. The long sides may be longer than the short sides. The lengths of the short sides of the upper surface and the lower surface may be equal to each other.

The long sides may extend in the first direction (x-axis direction). Therefore, the width Wx of the hexagonal columnar shape in the first direction (x-axis direction) can be wider than the width Wy in the second direction (y-axis direction).

The six sides are perpendicular to the first direction (x-axis direction) and the second direction (y-axis direction), and the six sides are perpendicular to the first direction (x-axis direction) and the second direction And may be parallel to the third direction (z-axis direction in Fig. 2).

Of the six sides, two sides facing each other may be parallel to each other. The six sides may include two large area side surfaces and four small area side surfaces. The two wide sides may be connected to the long sides of the upper surface and the lower surface. And each of the two wide sides may be wider than the area of each of the four narrow sides.

The two wide sides and the four narrow sides may have the same height in the third direction (z-axis direction). The width (Wz, height) in the third direction (z-axis direction) can be adjusted according to the concentration of SDBS added to the first mixed liquid described with reference to Fig. According to one embodiment, the width (Wz, height) in the third direction (z-axis direction) of the hexagonal pillar shape decreases as the concentration of SDBS increases, and as the concentration of SDBS decreases, The width (Wz, height) in the third direction (z-axis direction) can be increased. The SDBS may control the amount of the hexagonal columnar pores.

2, the lower and upper surfaces of the hexagonal column shape according to another embodiment of the present invention may have a regular hexagon shape.

Hereinafter, characteristics evaluation results of the porous structure according to the above-described embodiment of the present invention will be described with reference to FIGS. 3A, 3B, and 4. FIG.

FIG. 3A is a SEM photograph of a precursor structure according to an embodiment of the present invention, and FIG. 3B is a SEM photograph of a porous structure according to an embodiment of the present invention.

3A and 3B, 2 g of oxalic acid and 0.2 g of sodium dodecylbenzenesulfonate (SDBS) were added to 90 ml of ultrapure water, and ultrapure water to which oxalic acid and SDBS had been added was mixed with 30 ml of ethanol, .

Then, 5 ml of titanium butoxide (TBT) and 0.3 ml of acetic acid were mixed with 60 ml of ethanol to prepare a second mixed solution.

The first mixed solution was heat-treated to have a temperature of 90 캜, and then 1 ml of the second mixed solution containing titanium was added to the first mixed solution at 90 캜. The second mixed solution was added to the first mixed solution, and then the first mixed solution and the second mixed solution were reacted at 90 ° C for 4 hours to prepare a hexagonal columnar precursor structure, hydroxyl titanium oxalate. As can be seen from FIG. 3A, it can be seen that as the reaction time of the first mixed solution and the second mixed solution has elapsed, the precursor structure approaches the hexagonal columnar shape.

After reacting the first mixed solution with the second mixed solution, the hexagonal column-shaped intermediate product was separated by operating the centrifugal separator at 7500 rpm for 20 minutes, and washed once with ultra pure water and once with ethanol. Thereafter, it was dried in a vacuum oven at 80 DEG C for 2 hours.

0.5 g of the precursor structure and 0.27 g of LiOH were mixed with 25 ml of ultrapure water to prepare a source solution. 50 ml of the source solution was heat-treated in an auto clave at 180 ° C for 6 hours to prepare a hexagonal columnar porous structure formed of lithium titanium oxide as shown in FIG. 3b. Thereafter, the centrifugal separator was operated at 7500 rpm for 20 minutes to separate the porous structure in the form of a hexagonal column, and once with ultra pure water and once with ethanol. Then, it was dried in a vacuum oven at 70 DEG C for 4 hours.

As can be seen from FIGS. 3A and 3B, it can be seen that the hexagonal pillar-shaped porous structure is produced while maintaining the hexagonal pillar shape of the precursor structure.

4 is an XRD graph of a porous structure made according to an embodiment of the present invention.

Referring to FIG. 4, porous structures according to the first to sixth embodiments were manufactured by varying the weight ratio of the lithium salt and the precursor structure according to the embodiment of the present invention described above.

division Weight ratio of lithium salt and precursor structure pH First Embodiment 5: 4 13 Second Embodiment 5: 5 12.5 Third Embodiment 4: 5 12 Fourth Embodiment 3: 5 10 Fifth Embodiment 2: 5 9.5 Sixth Embodiment 1: 5 9

Specifically, as shown in Table 1, the weight ratio of the lithium salt and the precursor structure was varied to 5: 4, 5: 5, 4: 5, 3: 5, 2: 5, Or the pH of the solution was adjusted to prepare the porous structures according to the first to sixth embodiments. Thereafter, X-ray diffraction analysis was performed on the porous structures according to the first to sixth embodiments.

As a result of the X-ray diffraction analysis, it can be seen that the composition of the porous structure changes depending on the weight ratio of the lithium salt and the precursor structure. In addition, when the weight ratio of the lithium salt and the precursor structure was 5: 4 and 5: 5 according to the first and second embodiments, the presence of Anatase TiO ₂ and Rutile TiO ₂ in the porous structure was measured.

Further, when the weight ratio of the lithium salt and the precursor structure is 4: 5 according to the third embodiment, it is confirmed that the content of Li ₄ Ti ₅ O ₁₂ has a maximum value in comparison with the fourth to sixth embodiments . In other words, it can be confirmed that controlling the weight ratio of the lithium salt and the precursor structure to 4: 5 is an effective method of maximizing the content of Li ₄ Ti ₅ O _{12 in} the porous structure.

A lithium secondary battery including a negative electrode active material having a porous structure according to the above-described embodiment of the present invention will be described with reference to FIG.

5 is a view illustrating a lithium secondary battery including a porous structure according to an embodiment of the present invention.

5, a lithium secondary battery according to an embodiment of the present invention includes a cathode, a cathode active material 320, and a second current collector 325 including a first current collector 315 and a negative active material 310, An electrolyte 330, and a separator 340. The separator 340 may include a cathode,

The negative electrode active material 310 may include a porous structure according to an embodiment of the present invention with reference to FIGS. According to one embodiment, the anode active material 310 may include lithium, carbon, silicon, aluminum, tin, or tantalum in addition to the porous structure according to an embodiment of the present invention. And may further include at least one of magnesium (Mg), indium (In), and vanadium (V).

The first current collector 315 may be formed of a conductive material. For example, the first current collector 315 may be formed of copper, nickel, stainless steel, or the like.

According to one embodiment, the cathode active material 320 may include LiMO ₂ (M = V, Cr, Co, Ni), LiM ₂ O ₄ (M = Mn, Ti, V), LiMPO ₄ At least _{one of} LiNi _1-x Co _x O ₂ (0 <x <1), LiNi _2-x Mn _x O ₄ (0 <x <2), or Li [NiMnCo] O ₂ &Lt; / RTI &gt; The cathode active material may have a layered structure, a spinel structure, or an olivine structure depending on the kind of the active material used. Alternatively, according to another embodiment, oxygen (O ₂ ) may be used as the cathode active material 320.

The second current collector 325 may be formed of a conductive material. For example, the second current collector 325 may be formed of conductive carbon, stainless steel, aluminum, nickel, or the like.

The electrolyte (330) may be disposed between the cathode and the anode. The electrolyte 330 may be a gel polymer electrolyte or a liquid electrolyte. For example, the electrolyte 330 may be prepared by dissolving dimethyl carbonate (DC), ethylmethyl carbonate (PC), or the like in a basic solvent containing ethylene carbonate (EC), propylene carbonate EMC), and the like, and the lithium salt may be dissolved. For example, the lithium _{salt, LiN (CF 3 SO 2)} 2, LiN (FSO 2) 2, LiN (C 2 F 5 SO 2) 2, LiC (CF 2 SO 2) 3, LiBF 4, LiPF 6 , LiClO ₄ , LiCF ₃ SO ₃ , or LiAsF ₆ .

The separator 340 may be formed of a glass fiber, an olefin resin, a fluorine resin (e.g., polyvinylidene fluoride, polytetrafluoroethylene), an ester resin (e.g., polyethylene terephthalate) Or a cellulose-based nonwoven fabric. The separation membrane 340 may be formed of various kinds of materials in addition to the examples described above.

Hereinafter, the characteristics evaluation results of the lithium secondary battery including the composite structure according to the embodiment of the present invention described above will be described with reference to FIG.

6 is a graph illustrating a discharge capacity characteristic of a lithium secondary battery including a porous structure according to an embodiment of the present invention.

Referring to FIG. 6, the porous structures according to the first to third embodiments described with reference to FIG. 4, Anatase TiO ₂ , and lithium titanium oxide (LTO) having no hexagonal pillar shape are prepared, Thereby preparing cathodes.

Using the produced negative electrodes, the lithium secondary batteries according to the first to third embodiments and the lithium secondary batteries according to the first and second comparative examples were manufactured as shown in Table 2 below.

division Anode active material First Embodiment A lithium salt and a precursor structure were prepared in a weight ratio of 5: 4 Second Embodiment A lithium salt and a precursor structure were prepared in a weight ratio of 5: 5 Third Embodiment A lithium salt and a precursor structure were prepared in a weight ratio of 4: 5 Comparative Example 1 Anatase TiO ₂ Comparative Example 2 Lithium titanium oxide (LTO) having no hexagonal column shape

As can be seen from FIG. 6, according to the second and third embodiments, the discharge capacity of the lithium secondary battery including the porous structure in which the lithium salt and the precursor structure are manufactured in a weight ratio of 5: 5 and 4: 5, and it can be confirmed that the more excellent discharge capacity of a lithium secondary battery comprising a lithium titanium oxide (LTO) having no Anatase TiO ₂ and a hexagonal prism shape according to the second comparative example.

Also, as described with reference to FIG. 4, the amount of components of the porous structure varies depending on the weight ratio of the lithium salt and the precursor structure, and the amount of the lithium secondary battery according to the first to third embodiments shown in FIG. It can be seen that the discharge capacity of the lithium secondary battery is controlled by the composition ratio of the porous structure depending on the weight ratio of the lithium salt and the precursor structure.

The lithium secondary battery according to the embodiment of the present invention can be applied to various applications. For example, the lithium secondary battery according to the embodiment of the present invention can be applied to an electric vehicle to be described later.

7 is a block diagram of an electric vehicle according to an embodiment of the present invention.

An electric vehicle 1000 according to an embodiment of the present invention includes at least one of a motor 1010, a transmission 1020, an axle 1030, a battery pack 1040 and a power control unit 1050 and a charging unit 1060 can do.

The motor 1010 can convert the electric energy of the battery pack 1040 into kinetic energy. The motor 1010 may provide the converted kinetic energy to the axle 1030 through the transmission 1020. [ The motor 1010 may be composed of a single motor or a plurality of motors. For example, when the motor 1010 includes a plurality of motors, the motor 1010 may include a front wheel motor for supplying kinetic energy to the front wheel axle and a rear wheel motor for supplying kinetic energy to the rear wheel axle.

The transmission 1020 is positioned between the motor 1010 and the axle 1030 and can shift the kinetic energy from the motor 1010 to the axle 1030 in accordance with the operating environment desired by the driver have.

The battery pack 1040 can store electric energy from the charging unit 1060 and can supply the stored electric energy to the motor 1010. [ The battery pack 1040 can supply electric energy directly to the motor 1010 or supply electric energy through the power controller 1050.

At this time, the battery pack 1040 may include at least one battery cell. Also, the battery cell may include the lithium secondary battery according to the embodiment of the present invention. However, the battery cell is not limited thereto and may include various types of secondary batteries such as a lithium secondary battery. On the other hand, a battery cell may be a term referring to an individual battery, and a battery pack may refer to an assembly of battery cells in which individual battery cells are interconnected to have a desired voltage and / or capacity.

The power control unit 1050 can control the battery pack 1040. In other words, the power control unit 1050 can control the power from the battery pack 1040 to the motor 1010 to have required voltage, current, waveform, and the like. To this end, the power controller 1050 may include at least one of a passive power device and an active power device.

The charging unit 1060 may supply power to the battery pack 1040 by receiving power from the external power source 1070 shown in FIG. The charging unit 1060 can control the charging state as a whole. For example, the charging unit 1060 can control on / off and charge speed of the charge.

8 is a perspective view of an electric vehicle according to an embodiment of the present invention.

Referring to FIG. 8, the base battery pack 1040 may be coupled to the lower surface of the electric vehicle 1000. For example, the battery pack 1040 may have a width in the width direction of the electric vehicle 1000 and a shape extending in the longitudinal direction of the vehicle 1000. More specifically, the battery pack 1040 may extend from the front suspension to the rear suspension. Accordingly, the battery pack 1040 can provide a space for packaging a greater number of battery cells. In addition, since the battery pack 1040 is engaged with the lower end of the vehicle body, the center of gravity of the vehicle body is lowered, thereby improving the running safety of the electric vehicle 1000.

9 is a view for explaining a battery pack according to an embodiment of the present invention.

Referring to FIG. 9, the battery pack 1040 may store a plurality of battery cells 1043.

The battery pack 1040 may include a lower housing 1041 and an upper housing 1042. The lower housing 1041 may include a flange 1044 and a bolt 1045 may be fastened to the flange 1044 through a hole provided in the upper housing 1045 so that the lower housing 1041, The upper housing 1042 can be engaged.

At this time, in order to improve the stability of the battery pack 1040, the lower and upper housings may be made of a material that minimizes moisture and oxygen penetration. For example, the lower and upper housings may be made of at least one of aluminum, aluminum alloy, plastic, and carbon. An impermeable sealant 1049 may be disposed between the lower housing 1041 and the upper housing 1042.

In addition, the battery pack 1040 may include a structure for controlling the battery cell 1043 or improving stability. For example, the battery pack 1040 may include a control terminal 1047 for controlling the battery cell 1043 in the battery pack 1040. Also, for example, the battery pack 1040 may include a cooling line 1046 to prevent thermal runaway of the battery cell 1043 or to control the temperature of the battery cell 1043 . In addition, for example, the battery pack 1040 may include a gas ejection port 1048 for ejecting gas inside the battery pack 1040.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the scope of the present invention is not limited to the disclosed exemplary embodiments. It will also be appreciated that many modifications and variations will be apparent to those skilled in the art without departing from the scope of the invention.

100: precursor structure
200: Porous structure
310: anode active material
315: 1st Total
320: cathode active material
325: The 2nd Collection
330: electrolyte
340: Membrane

Claims (10)

Preparing a hexagonal columnar precursor structure comprising titanium; And
And mixing and heat-treating the lithium salt to the precursor structure to produce a hexagonal columnar porous structure containing lithium titanium oxide.
The method according to claim 1,
Wherein the porous structure has a higher pore level than the precursor structure.
The method according to claim 1,
Wherein the step of fabricating the precursor structure comprises:
Preparing a first mixed liquid in which oxalic acid and sodium dodecylbenzenesulfonate (SDBS) are mixed; And
And adding the first mixed solution to a second mixed solution containing titanium.
The method of claim 3,
Further comprising the step of heat treating the first mixed solution before adding the second mixed solution to the first mixed solution.
The method according to claim 1,
Wherein the step of fabricating the porous structure comprises:
Dispersing the precursor structure and the lithium salt in a solvent to prepare a source solution;
Heat treating the source solution to produce the porous structure;
Separating the porous structure from the source solution; And
And washing and drying the porous structure.
The method according to claim 1,
Wherein the lithium salt and the precursor structure are mixed at a weight ratio of 4: 5.
A negative electrode active material comprising lithium titanium oxide and a porous structure having a hexagonal columnar shape.
8. The method of claim 7,
The porous structure may include:
Wherein the negative electrode active material is defined by a plurality of particles, and pores are defined between the plurality of particles.
8. The method of claim 7,
Wherein the porous structure is made from a precursor structure containing titanium oxide and having a hexagonal pillar shape,
Wherein the porous structure has a surface area higher than that of the precursor structure.
A negative electrode comprising the negative active material according to any one of claims 7 to 9;
A positive electrode facing the negative electrode; And
An electrolyte between the cathode and the anode, and a separator.

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