KR102187204B1 - Lithium primary battery having inorganic coating layer with excellent thermal stability - Google Patents

Abstract

Disclosed is a lithium primary battery having an inorganic coating layer having excellent thermal stability designed to overcome the initial voltage delay phenomenon generated in the initial discharge process.
The lithium primary battery having an inorganic coating layer having excellent thermal stability according to the present invention is a case in which the upper side is opened and an electrolyte is impregnated therein; A lithium negative electrode disposed inside the case; A positive electrode disposed inside the case to face the lithium negative electrode; A separator disposed between the lithium negative electrode and the positive electrode; And a header covering and sealing the upper side of the case, wherein the lithium negative electrode includes a lithium metal layer and an inorganic coating layer covering a surface of the lithium metal layer.

Description

Lithium primary battery with an inorganic coating layer with excellent thermal stability {LITHIUM PRIMARY BATTERY HAVING INORGANIC COATING LAYER WITH EXCELLENT THERMAL STABILITY}

The present invention relates to a lithium primary battery having an inorganic coating layer having excellent thermal stability, and more specifically, a lithium primary battery having an inorganic coating layer having excellent thermal stability designed to overcome the initial voltage delay phenomenon generated in the initial discharge process. It is about.

In general, a battery is a driving source that generates electricity by inducing an oxidation/reduction reaction of a chemical substance, and it is easy to carry and can be manufactured in a small size, so it is used for supplying electricity to various types and purposes of equipment.

Lithium thionyl chloride battery (Li/SOCl ₂ ), which is a lithium primary battery, has excellent energy density and high operating voltage characteristics of 3 V or more, and is thus widely used as a power source with high capacity and long-term reliability.

Lithium thionyl chloride batteries with these advantages also form lithium chloride (LiCl), which is a non-conductive film on the surface of lithium when used after a long period of storage, resulting in an increase in internal resistance, resulting in an initial voltage delay and a decrease in operating voltage. There was a problem.

To solve this problem, conventionally, a cathode treatment technology in which a cyanoacrylate-based organic material is coated on the surface of a lithium anode has been applied.

However, this technology shortened the initial voltage delay time to within a few seconds to several hundreds of seconds, but did not improve the phenomenon of a decrease in the Transient Minimum Voltage (TMV) after high temperature storage of 70°C or higher.

In addition, the conventional cathode treatment technology coated with a cyanoacrylate-based organic material is a gas generated by a chemical reaction in a sulfonyl (SO ₂ Cl ₂ ) electrolyte or thionyl (SOCl ₂ ) electrolyte. There was a problem that the product was accumulated and the internal pressure of the battery was continuously increased.

In addition, since the organic coating layer exhibits a problem of fracture due to deformation and curing at a temperature equal to or higher than the thermal deformation temperature of the polymer, there is a problem in that it is vulnerable to safety such as performance degradation and ignition during thermal shock.

As a related prior document, there is Korean Patent Publication No. 10-0873166 (Announcement on Dec. 10, 2008), and a lithium/thionyl chloride battery is described in the document.

It is an object of the present invention to provide a lithium primary battery having an inorganic coating layer having excellent thermal stability designed to overcome the initial voltage delay phenomenon generated in the initial discharge process.

A lithium primary battery having an inorganic coating layer having excellent thermal stability according to an embodiment of the present invention for achieving the above object is a case in which the upper side is opened and an electrolyte is impregnated therein; A lithium negative electrode disposed inside the case; A positive electrode disposed inside the case to face the lithium negative electrode; A separator disposed between the lithium negative electrode and the positive electrode; And a header covering and sealing the upper side of the case, wherein the lithium negative electrode includes a lithium metal layer and an inorganic coating layer covering a surface of the lithium metal layer.

The lithium negative electrode, the positive electrode, and the separator have a winding structure wound in a roll shape inside the case.

The inorganic coating layer has a thickness of 1 ~ 100㎛.

The inorganic coating layer includes 70 to 99% by weight of ceramic particles and 1 to 30% by weight of a binder.

At this time, the ceramic particles are Li _{1 + x} Al _x Ge _{2 -x} (PO ₄ ) ₃ (LAGP), Li _{1 + x} Al _x Ti _{2 -x} (PO ₄ ) ₃ (LATP), Li _{1 + x} Ti _{2 - x Al x Si y (PO} 4) 3 -y, LiAl x Zr 2 -x (PO 4) 3, LiTi x Zr 2 -x (PO 4) 3, Li 10 GeP 2 S 12 (LGPS) and Al ₂ It may include at least one selected from among ceramic materials including O ₃ .

(Where 0 ≤ x ≤ 1, 0 ≤ y ≤ 1)

It is preferable that the ceramic particles have an average particle size of 1 to 30 μm.

In addition, the binder includes at least one selected from polyvinyl chloride (PVC), polyvinylpyrrolidone (PVP), polyvinyleden floride (PVDF), polyvinyl alcohol (PVA), and epoxy resin.

The lithium primary battery having an inorganic coating layer having excellent thermal stability according to the present invention does not coat a cyanoacrylate-based organic material on the surface of a lithium negative electrode, but forms an inorganic coating layer including ceramic particles and a binder. Thereby, it is possible to reduce the generation of internal pressure by minimizing organic matter.

In the conventional technology of coating an organic material by heat generated at the end of discharge, there was a possibility of deformation and ignition of the coating layer, but the lithium primary battery having an inorganic coating layer having excellent thermal stability according to the embodiment of the present invention has a flash point on the surface of the lithium anode. And by forming a ceramic-based inorganic coating layer having a considerably high heat deflection temperature, it is possible to effectively disperse heat generated from the lithium negative electrode, thus ensuring excellent thermal stability, as well as the possibility of deformation and ignition of the coating layer. It can be solved.

As a result, the lithium primary battery having an inorganic coating layer having excellent thermal stability according to the present invention can effectively improve the initial voltage delay because the ceramic particle strength is higher than that of the conventional polymer, even in surface strength that directly contributes to the initial voltage delay phenomenon. .

1 is a cross-sectional view showing a lithium primary battery having an inorganic coating layer excellent in thermal stability according to an embodiment of the present invention.
2 is a plan view showing a lithium primary battery having an inorganic coating layer excellent in thermal stability according to an embodiment of the present invention.
3 is an enlarged cross-sectional view of the lithium anode of FIG. 1.
4 is a graph showing results of evaluating initial output characteristics of lithium primary batteries manufactured according to Example 1 and Comparative Example 1;
5 is a graph showing the results of evaluating output characteristics of lithium primary batteries manufactured according to Example 2 and Comparative Example 2. FIG.

Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in a variety of different forms, only this embodiment is to complete the disclosure of the present invention, and the general knowledge in the technical field to which the present invention pertains. It is provided to completely inform the scope of the invention to those who have it, and the invention is only defined by the scope of the claims. The same reference numerals refer to the same elements throughout the specification.

Hereinafter, a lithium primary battery having an inorganic coating layer having excellent thermal stability according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view showing a lithium primary battery having an inorganic coating layer having excellent thermal stability according to an embodiment of the present invention, and FIG. 2 is a plan view showing a lithium primary battery having an inorganic coating layer having excellent thermal stability according to an embodiment of the present invention to be.

1 and 2, a lithium primary battery 100 having an inorganic coating layer having excellent thermal stability according to an embodiment of the present invention includes a case 110, a lithium negative electrode 120, a positive electrode 130, and a separator 140. ) And a header 150.

The upper side of the case 110 is opened, and an electrolyte is impregnated therein. The case 110 may have a cylindrical shape in which the upper side is open, or may be designed in a rectangular shape such as a rectangular parallelepiped or a hexagonal column. Stainless steel (SUS) may be used as the material of the case 110, but is not limited thereto.

In this case, as the electrolyte, a sulfonyl (SO ₂ Cl ₂ ) electrolyte or a thionyl (SOCl ₂ ) electrolyte may be used, but is not limited thereto.

The lithium negative electrode 120 is disposed inside the case 110 and is wound to face the positive electrode 130. The lithium negative electrode 120 is electrically separated from the positive electrode 130 by the separator 140. In particular, in the present invention, the lithium negative electrode 120 may have an inorganic coating layer (124 in FIG. 3), and a detailed configuration of the lithium negative electrode 120 will be described later.

The anode 130 is disposed inside the case 110 and is disposed to face the cathode 120 and wound. In this case, the anode 130 may be made of a material composed of carbon and a binder, but is not limited thereto.

The separator 140 is disposed between the lithium negative electrode 120 and the positive electrode 130. Accordingly, the lithium negative electrode 120, the positive electrode 130, and the separator 140 have a winding structure wound in a roll shape inside the case 110, and are inserted into the case 110 in which the upper side is opened.

The separator 140 is disposed between the lithium negative electrode 120 and the positive electrode 130 to electrically separate the lithium negative electrode 120 and the positive electrode 130. At this time, as the material of the separator 140, glass fiber, polyethylene (PE), polypropylene (PP), polyvinylidene fluoride (PVDF), polyvinylidene chloride (PVDC), polyacrylonitrile ( PAN), polyacrylamide (PAAm), polytetrafluoroethylene (PTFE), polysulfone, polyethersulfone (PES), polycarbonate (PC), polyamide (PA), polyimide (PI), polyethylene oxide ( PEO), polypropylene oxide (PPO), a cellulose-based polymer, and a microporous film prepared using one or more polymers selected from the group consisting of polyacrylic polymers may be used. In addition, the separator 140 may be a multilayer film obtained by polymerizing a porous film.

The header 150 covers and seals the upper side of the case 110. The header 150 may be bonded to the case 110 by spot welding or laser welding. At this time, the header 150 may be coupled to the glass 170, and the header pin 160 may be fastened to the central portion of the header 150.

In addition, although not shown in detail in the drawings, the header 150 may be provided with an electrolyte injection port (not shown) for impregnating the electrolyte.

At this time, in the present invention, a lithium negative electrode 120 and a positive electrode 130, and a separator 140 between the lithium negative electrode 120 and the positive electrode 130 are stacked in a parallel structure in the case 110 with the upper side open. In the form of a roll (ROLL) has a winding structure, the lithium negative electrode 120, the positive electrode 130, and the separator 140 are inserted in the center of the case 110. Thereafter, the upper side of the case 110 is welded with the header 150, and the electrolyte is impregnated into the case 110 through the electrolyte injection port of the header 150, and finally, a subball (not shown) as a finishing material. It is sealed by welding.

In this case, an upper insulating plate 145 may be further disposed on the lower surface of the header 150. The upper insulating plate 145 prevents leakage of the electrolyte inside the case 110.

Meanwhile, FIG. 3 is an enlarged cross-sectional view of the lithium anode of FIG. 1, and will be described in more detail with reference to this.

As shown in FIG. 3, a lithium negative electrode 120 according to an embodiment of the present invention includes a lithium metal layer 122 and an inorganic coating layer 124 covering the surface of the lithium metal layer 122.

As described above, in the present invention, by forming the inorganic coating layer 124 on the surface of the lithium metal layer 122, the inorganic coating layer 124 can suppress the growth of LiCl, as well as the lithium metal layer 122 It can contribute to stability improvement by effectively dispersing heat. As a result, it is possible to improve the electrical output characteristics and thermal stability of the lithium primary battery.

To this end, the inorganic coating layer 124 includes ceramic particles and a binder. More specifically, the inorganic coating layer 124 preferably includes 70 to 99% by weight of ceramic particles and 1 to 30% by weight of a binder.

Ceramic particles are Li _{1 + x} Al _x Ge _{2 -x} (PO ₄ ) ₃ (LAGP), Li _{1 + x} Al _x Ti _{2 -x} (PO ₄ ) ₃ (LATP), Li _{1 + x} Ti _{2 -x} Al _x Si _y (PO ₄ ) _3-y , LiAl _x Zr _{2 -x} (PO ₄ ) ₃ , LiTi _x Zr _{2 -x} (PO ₄ ) _3, Li ₁₀ GeP ₂ S ₁₂ (LGPS) and Al ₂ O ₃ It includes at least one selected from among ceramic materials, and it is preferable to use LATP.

Here, 0≤x≤1, and 0≤y≤1.

In addition, the binder may include at least one selected from PVC (polyvinyl chloride), PVP (polyvinylpyrrolidone), PVDF (polyvinyleden floride), PI (polyimide), PVA (polyvinyl alcohol), and epoxy resin. It is preferable to use PVC.

When the amount of the ceramic particles added is less than 70% by weight, it may be difficult to properly exhibit the heat dissipation effect. Conversely, when the amount of ceramic particles added exceeds 99% by weight, the binder content is low, and thus the coating layer may be desorbed due to a decrease in binding strength.

It is preferable that the inorganic coating layer 124 has a thickness of 1 to 100 μm. If the thickness of the inorganic coating layer 124 is less than 1 μm, the thickness is too thin and the heat dissipation effect is weak, so it may be difficult to properly exhibit the effect of improving the thermal stability, and it is not possible to effectively hinder the growth of LiCl. It may not be. On the contrary, if the thickness of the inorganic coating layer 124 exceeds 100 μm, it is not economical because it can act as a factor that increases only the thickness without further increasing the effect, and the battery output may decrease due to the increase in internal resistance due to the increase in thickness. I can.

In addition, it is preferable to use ceramic particles having an average particle size of 1 to 30 µm. When the average particle size of the ceramic particles is less than 1 μm, the adhesion may be lowered due to the problem of dispersibility of the particles as the size becomes fine. Conversely, when the average particle size of the ceramic particles exceeds 30 μm, it may be difficult to properly exhibit the effect of improving thermal stability since the binder content must be increased relatively.

As described so far, the lithium primary battery having an inorganic material coating layer having excellent thermal stability according to an embodiment of the present invention does not coat a cyanoacrylate-based organic material on the surface of a lithium negative electrode, but ceramic particles and By forming the inorganic coating layer including the binder, it is possible to reduce the generation of internal pressure by minimizing organic substances.

In the conventional technology of coating an organic material by heat generated at the end of discharge, there was a possibility of deformation and ignition of the coating layer, but the lithium primary battery having an inorganic coating layer having excellent thermal stability according to the embodiment of the present invention has a flash point on the surface of the lithium anode. And by forming a ceramic-based inorganic coating layer having a considerably high heat deflection temperature, it is possible to effectively disperse heat generated from the lithium negative electrode, thus ensuring excellent thermal stability, as well as the possibility of deformation and ignition of the coating layer. It can be solved.

As a result, the lithium primary battery having an inorganic coating layer having excellent thermal stability according to an embodiment of the present invention has higher ceramic particle strength than the polymeric prior art even in surface strength that directly contributes to the initial voltage delay phenomenon, thus effectively improving the initial voltage delay. can do.

Example

Hereinafter, the configuration and operation of the present invention will be described in more detail through preferred embodiments of the present invention. However, this is presented as a preferred example of the present invention and cannot be construed as limiting the present invention in any sense.

Contents not described herein can be sufficiently technically inferred by those skilled in the art, and thus description thereof will be omitted.

One. Lithium primary battery Produce

Example One

A lithium negative electrode was prepared by forming an inorganic coating layer composed of 85 wt% of LATP and 15 wt% of PVC (polyvinyl chloride) having an average particle size of 17 μm on the surface of the lithium metal layer to a thickness of 25 μm.

Next, a long separator was placed between the lithium negative electrode and the positive electrode, wound up in a rolled structure, and inserted into a case where the upper side was opened.

Next, after welding the upper side of the case with the header, the electrolyte was injected into the case through the electrolyte injection port of the header and sealed to manufacture a lithium primary battery.

Example 2

The same method as in Example 1 except that a lithium negative electrode was prepared by forming an inorganic coating layer composed of 76wt% of LATP and 24wt% of PVC (polyvinyl chloride) having an average particle size of 11㎛ on the surface of the lithium metal layer to a thickness of 100㎛. To prepare a lithium primary battery.

Comparative example One

A lithium negative electrode composed of only a lithium metal layer was prepared without forming an inorganic coating layer.

Next, a long separator was placed between the lithium negative electrode and the positive electrode, wound up in a rolled structure, and inserted into a case where the upper side was opened.

Next, after welding the upper side of the case with the header, the electrolyte was injected into the case through the electrolyte injection port of the header and sealed to manufacture a lithium primary battery.

Comparative example 2

An organic material coating layer made of cyanoacrylate was formed on the surface of the lithium metal layer to a thickness of 120 μm to prepare a lithium negative electrode.

Next, a long separator was placed between the lithium negative electrode and the positive electrode, wound up in a rolled structure, and inserted into a case where the upper side was opened.

Next, after welding the upper side of the case with the header, the electrolyte was injected into the case through the electrolyte injection port of the header and sealed to manufacture a lithium primary battery.

2. Property evaluation

Table 1 shows a comparison of the properties of the coating materials used in Example 1 and Comparative Example 2.

[Table 1]

As shown in Table 1, cyanoacrylate, an organic material, has a flash point of about 85 to 93°C, but LATP, which is a ceramic type, has a flash point of about 500°C or higher, which is considerably higher than that of an organic material.

In addition, cyanoacrylate, an organic material, has a heat deflection temperature of approximately 74 to 100°C, whereas a ceramic LATP has a heat deflection temperature of approximately 900°C or higher.

Meanwhile, FIG. 4 is a graph showing results of evaluating initial output characteristics of lithium primary batteries manufactured according to Example 1 and Comparative Example 1. At this time, after high temperature acceleration at 72° C. for 3 days storage conditions, the initial output of the lithium primary batteries prepared according to Example 1 and Comparative Example 1 was measured.

As shown in FIG. 4, the lithium primary battery prepared according to Example 1 in which the inorganic coating layer was formed has a remarkable initial output characteristic compared to the lithium primary battery manufactured according to Comparative Example 1 in which the coating layer was not formed on the lithium negative electrode. You can see that it is improved.

5 is a graph showing results of evaluating output characteristics of lithium primary batteries manufactured according to Example 2 and Comparative Example 2. At this time, after pre-discharging 1% of battery capacity and accelerating at high temperature under storage conditions at 72° C. for 3 days, the initial output of the lithium primary batteries prepared according to Example 2 and Comparative Example 2 was measured.

As shown in FIG. 5, it can be seen that the lithium primary battery manufactured according to Example 2 in which the inorganic coating layer was formed has improved output characteristics compared to the lithium primary battery manufactured according to Comparative Example 2 in which the organic coating layer was formed.

As can be seen from the above experimental results, the lithium primary batteries manufactured according to Examples 1 to 2 have not only excellent thermal stability due to their high flash point and thermal deformation temperature, but also lithium primary batteries manufactured according to Comparative Examples 1 to 2 It was confirmed that the electrical output characteristics were improved compared to.

In the above, the embodiments of the present invention have been described mainly, but various changes or modifications can be made at the level of those of ordinary skill in the art to which the present invention pertains. Such changes and modifications can be said to belong to the present invention as long as they do not depart from the scope of the technical idea provided by the present invention. Accordingly, the scope of the present invention should be determined by the claims set forth below.

100: lithium primary battery 110: case
120: lithium negative electrode 122: lithium metal layer
124: inorganic coating layer 130: anode
140: separator 150: header
160: header pin

Claims (7)

A case in which the upper side is opened and the electrolyte is impregnated therein;
A lithium negative electrode disposed inside the case;
A positive electrode disposed inside the case to face the lithium negative electrode;
A separator disposed between the lithium negative electrode and the positive electrode; And
Includes; a header covering and sealing the upper side of the case,
The lithium negative electrode includes a lithium metal layer and an inorganic coating layer covering the surface of the lithium metal layer,
The inorganic coating layer contains 76 to 85% by weight of ceramic particles and 15 to 24% by weight of a binder,
The ceramic particles have a flash point of 500° C. or higher and a heat deflection temperature of 900° C. or higher. Li _1+x Al _x Ge _2-x (PO ₄ ) ₃ (LAGP), Li _1+x Al _x Ti _2-x ( PO ₄ ) ₃ (LATP), Li _1+x Ti _2-x Al _x Si _y (PO ₄ ) _3-y , LiAl _x Zr _2-x (PO ₄ ) ₃ , LiTi _x Zr _2-x (PO ₄ ) Lithium primary battery having an inorganic coating layer having excellent thermal stability, characterized in that it comprises at least one selected from ceramic materials including ₃ and Li ₁₀ GeP ₂ S ₁₂ (LGPS).
(Where 0 ≤ x ≤ 1, 0 ≤ y ≤ 1)
The method of claim 1,
The lithium negative electrode, positive electrode, and separator are
Lithium primary battery having an inorganic coating layer having excellent thermal stability, characterized in that it has a winding structure wound in a roll form inside the case.
The method of claim 1,
The inorganic coating layer
Lithium primary battery having an inorganic coating layer having excellent thermal stability, characterized in that it has a thickness of 1 ~ 100㎛.
delete delete The method of claim 1,
The ceramic particles are
Lithium primary battery having an inorganic coating layer excellent in thermal stability, characterized in that it has an average particle size of 1 ~ 30㎛.
The method of claim 1,
The binder is
Excellent thermal stability, characterized by containing at least one selected from PVC (polyvinyl chloride), PVP (polyvinylpyrrolidone), PVDF (polyvinyleden floride), PI (polyimide), PVA (polyvinyl alcohol), and epoxy resin. Lithium primary battery having an inorganic coating layer.

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