WO2019112343A1 - Cylindrical secondary battery comprising piezoelectric element - Google Patents

Abstract

The present invention relates to a cylindrical secondary battery comprising: a jelly-roll shaped electrode assembly having a structure in which long sheet-shaped positive electrode and negative electrode are wound with a separator interposed between the electrodes; a cylindrical battery case for receiving the jelly-roll shaped electrode assembly; and a piezoelectric element for generating electrical energy by volume expansion according to charge and discharge of the jelly-roll shaped electrode assembly.

Description

Cylindrical secondary battery with built-in piezoelectric element

This application claims the benefit of priority under Korean Patent Application No. 2017-0166659, filed on December 6, 2017, the entire contents of which are incorporated herein by reference.

More particularly, the present invention relates to a cylindrical secondary battery having a built-in jelly-roll type electrode assembly, and more particularly, to a cylindrical battery cell having a jelly-roll type electrode assembly that generates electric energy And a piezoelectric element.

As technology development and demand for mobile devices have increased, rechargeable secondary batteries have been widely used as energy sources for mobile devices. In addition, the secondary battery is attracting attention as an energy source for electric vehicles, hybrid electric vehicles, and the like, which is proposed as a solution for air pollution in existing gasoline vehicles and diesel vehicles using fossil fuels.

2. Description of the Related Art Generally, a secondary battery includes a cylindrical battery and a prismatic battery in which an electrode assembly is embedded in a cylindrical or rectangular metal can according to the shape of a battery case, and a pouch type battery in which an electrode assembly is embedded in a pouch- .

The electrode assembly embedded in the battery case includes a positive electrode, a negative electrode, and a separation membrane structure interposed between the positive electrode and the negative electrode. The power generation device includes a separator interposed between a positive electrode and a negative electrode coated with an active material, A jelly-roll type, and a plurality of positive electrodes and a negative electrode of a predetermined size, which are stacked in a stacked state with a separator interposed therebetween. Among them, the jelly-roll type electrode assembly is widely used in applications requiring a high-capacity secondary battery because it is easy to manufacture and has a high energy density per weight.

That is, a cylindrical battery in which the jelly-roll type electrode assembly is housed in a cylindrical battery case is used in accordance with a demand for a high energy density and high capacity battery. Since the cylindrical battery uses a metal can having a relatively high rigidity as compared with the pouch type battery, it is difficult to enlarge the space inside the battery. As described above, there is a problem that it is difficult to increase the energy density of the cylindrical battery and to improve the energy efficiency, unless the space utilization aspect is not high and the energy efficient material is not developed.

Korean Patent Registration No. 1261705 discloses a pouch-type battery, which includes a battery case having a piezoelectric element layer and a protection circuit module having a voltage storage unit. The piezoelectric element layer converts the absorbed vibration into a voltage, And the secondary battery can be charged by itself if necessary.

However, since the secondary battery is a pouch type battery, there is a difference in the type of the battery, and in order to store electricity generated in the piezoelectric element layer, the secondary battery further includes a member separate from the voltage storage unit. .

Korean Patent Publication No. 1708456 discloses a capacitor charging system including a piezoelectric element that generates electric power by using a pressure generated by a swelling phenomenon of a battery cell and a capacitor connected to the piezoelectric element to receive charging power The piezoelectric element is difficult to apply to the inside of the cylindrical battery in that it is located between battery cells or between the battery cell and the module case.

Thus, when a cylindrical battery having a high energy density per unit weight is used, there is a high need for a technique capable of self-charging the battery without increasing the size of the battery and without requiring a separate storage space.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and it is an object of the present invention to provide a jelly-roll type electrode assembly that includes a piezoelectric element that generates electric energy by volume expansion due to charge / discharge of a jelly- The present invention can provide a cylindrical secondary battery having a high energy density capable of additionally producing electrical energy in addition to electricity generated by charging a bar and a jelly-roll type electrode assembly housed in the cylindrical secondary battery.

According to an aspect of the present invention, there is provided a cylindrical secondary battery,

A jelly-roll type electrode assembly having a structure in which a separation membrane is interposed between a positive electrode and a negative electrode of a long sheet type;

A cylindrical battery case for accommodating the jelly-roll type electrode assembly; And

And a piezoelectric element for generating electrical energy by volume expansion due to charge and discharge of the jelly-roll type electrode assembly.

That is, the cylindrical secondary battery according to the present invention uses a jelly-roll type electrode assembly capable of repeated charging and discharging, and electric energy can be obtained by charging the electrode assembly. However, various attempts have been made to improve the energy density of the cylindrical rechargeable battery according to the demand for a high capacity and high energy density battery, but there is a problem that a long time is required to develop a material having high energy efficiency.

Accordingly, the present invention is characterized in that the cylindrical secondary battery includes a piezoelectric element, and the piezoelectric element generates energy by volume change of the jelly-roll type electrode assembly in which expansion and contraction occur repeatedly during charging and discharging, There is an advantage that the battery can be self-generated during use.

The piezoelectric element is a material in which a potential difference is generated when a physical force or vibration is applied and a balance between a positive charge and a negative charge is broken. As a result, when the jelly-roll type electrode assembly expands and pressure is applied to the piezoelectric element Electric energy is generated.

As described above, according to the present invention, it is possible to generate additional electric energy using the piezoelectric element in addition to electricity generated by charging the jelly-roll type electrode assembly. Thus, without increasing the overall size of the cylindrical secondary battery, Battery can be provided.

In one specific example, the piezoelectric element is added so as not to cause an increase in the overall volume of the cylindrical rechargeable battery, and in consideration of a position at which electric energy can be generated by the volume expansion of the jelly-roll type electrode assembly, For example, the piezoelectric element may be positioned between the jelly-roll type electrode assembly and the cylindrical battery case.

As described above, when the piezoelectric element is placed in contact with the jelly-roll type electrode assembly where expansion and contraction occur repeatedly in the charging and discharging process, or when the piezoelectric element is positioned at the adjacent position, the accuracy of pressure application to the piezoelectric element is increased, It is possible to increase the amount of electric energy generated by the piezoelectric element.

The additional area and position of the piezoelectric element can be selectively applied. For example, the piezoelectric element can be added to the tape for preventing the jelly-roll type electrode assembly from unwinding. When the piezoelectric element is added to the above position, it is possible to prevent the winding state of the jelly-roll type electrode assembly from being loosened as the jelly-roll type electrode assembly repeats expansion and contraction, and also to produce additional electric energy by the piezoelectric element .

In addition, the piezoelectric element may be attached to the inner surface of the cylindrical battery case, may be attached to the entire inner surface of the battery case, or may be attached only to the cylindrical side surface portion of the battery case.

The piezoelectric element may be added in the form of a tape having an adhesive layer formed on the opposite surface of the battery case, or may be added by a spraying method.

In one specific example, the cylindrical battery case comprises an outer case and an inner case in which a hollow is formed, and the hollow is provided with a piezoelectric element. That is, the entirety of the battery case including the cylindrical side surface and the bottom surface of the cylindrical battery case may be a structure including the outer case and the inner case.

Considering that the expansion direction of the jelly-roll type electrode assembly is the direction of centrifugal force with respect to the winding central axis, the cylindrical battery case has a cylindrical side surface having a double structure of an outer case and an inner case, So that the piezoelectric element may be added to the cylindrical side surface only.

The piezoelectric element may be at least one selected from the group consisting of natural piezoelectric materials, artificial piezoelectric crystals, lead-free piezoelectric ceramics, and artificial piezoelectric ceramics.

Specifically, the natural piezoelectric material may be bellinite (AlPO ₄ ), sucrose, quartz, rochelite, topaz, tourmaline, pearl, enamel or dentin. The artificial piezoelectric crystal may be made of gallium phosphide (GaPO ₄ ) (La ₃ Ga ₅ SiO ₁₄ ), and the lead-free piezoelectric ceramics may be NaKNb, BiFeO ₃ , NaNbO ₃ , Bi ₄ Ti ₃ O ₁₂ or Na _0.5 Bi _0.5 TiO ₃ Lt; / RTI >

The artificial piezoelectric ceramics includes BaTiO ₃ , NbTiO ₃ , KNbO ₃ , LiNbO ₃ , LiTaO _{3, and the like.} ), Sodium tungsten oxide (Na ₂ WO), zinc oxide (ZnO ₃ ), Ba ₂ NaNb ₅ O ₅ , and Pb ₂ KNb ₅ O ₁₅ .

In one specific example, since the electric energy generated by the piezoelectric element can be stored in the jelly-roll type electrode assembly and does not include a separate member for storing the electric energy generated by the piezoelectric element , It is possible to provide a cylindrical secondary battery having a high energy density per unit volume.

The present invention can also provide a battery pack including the cylindrical secondary battery.

Specifically, the battery pack may be used as a power source for devices requiring high-temperature safety, long cycle characteristics, and high rate characteristics. Examples of such devices include a mobile device, a wearable device A power tool powered by an electric motor; An electric vehicle including an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), and the like; An electric motorcycle including an electric bike (E-bike) and an electric scooter (E-scooter); An electric golf cart; And an energy storage system, but the present invention is not limited thereto.

The structure of these devices and their fabrication methods are well known in the art, and a detailed description thereof will be omitted herein.

1 is a vertical sectional view of a cylindrical secondary battery according to an embodiment.

2 is a vertical cross-sectional view of a cylindrical battery case according to one embodiment.

3 is a vertical cross-sectional view of a cylindrical battery case according to another embodiment.

4 is a perspective view of another jelly-roll type electrode assembly in one embodiment.

5 is a perspective view of another jelly-roll type electrode assembly according to another embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the detailed description of known functions and configurations incorporated herein will be omitted when it may unnecessarily obscure the subject matter of the present invention.

The same reference numerals are used for portions having similar functions and functions throughout the drawings. Throughout the specification, when a part is connected to another part, it includes not only a case where it is directly connected but also a case where the other part is indirectly connected with another part in between. In addition, the inclusion of an element does not exclude other elements, but may include other elements, unless specifically stated otherwise.

The present invention will be described in detail with reference to the drawings.

1 schematically shows a vertical sectional view of a cylindrical secondary battery according to one embodiment.

Referring to FIG. 1, a cylindrical secondary battery 100 includes a battery case 101 having a single layer 101 structure having a bottom and an open top, and an electrode assembly (not shown) And a piezoelectric element 110 is interposed between the first and second electrodes 120 and 120. The piezoelectric element 110 is formed between the lower surface of the battery case 101 and the electrode assembly 120 but may be formed only between the side surface of the battery case 101 and the side surface of the electrode assembly 120.

For convenience of explanation, illustration of the internal elements constituting the other cylindrical secondary battery is omitted.

Figs. 2 and 3 schematically show vertical sectional views of a cylindrical battery case according to different embodiments. Fig.

Referring to FIGS. 2 and 3, the battery cases 200 and 300 have a double structure having a bottom and an open cylindrical structure.

The battery case 200 is constituted by an outer case 201 and an inner case 202 and a hollow is formed between the outer case 201 and the inner case 202. In the hollow, . The battery case 200 is entirely constituted by the outer case 201 and the inner case 202 on the side surface and the bottom surface 205 as a whole.

The battery case 300 is constituted by an outer case 301 and an inner case 302 and a hollow is formed between the outer case 301 and the inner case 302. In the hollow, . The side surface of the battery case 300 is composed of an outer case 301 and an inner case 302, but the lower surface 305 is a single layer.

FIG. 4 is a perspective view of a jelly-roll type electrode assembly according to one embodiment, and FIG. 5 is a perspective view of a jelly-roll type electrode assembly according to another embodiment.

Referring to FIG. 4, the jelly-roll type electrode assembly 420 is shown with a piezoelectric element 410 attached to the entire outer surface of the sheet-shaped electrode. In this way, the piezoelectric element 410 can be attached to the outer surface of the jelly-roll type electrode assembly at 360 degrees, or the outer surface of the jelly-roll type electrode assembly is surrounded at 360 degrees, May be formed to be shorter than the length of the rolled electrode assembly.

Referring to FIG. 5, the jelly-roll type electrode assembly 520 shows a state where a piezoelectric element 510 is attached to a tape attached so as to prevent unwinding of the electrode assembly at the winding end. In such a case, in order to increase the amount of the piezoelectric element, it is preferable that the jelly-roll type electrode assembly is housed in a battery case having a piezoelectric element attached to its inner surface like the battery case 100 shown in Fig.

Since the outer case 101, 201, or 301 corresponds to the negative electrode in the case of the piezoelectric device of FIGS. 1, 2 and 3, the negative pole of the piezoelectric device is directly connected to the outer case 101, 201, Can be connected. The positive electrode of the piezoelectric element may be connected to the positive electrode of the top cap of the can type battery or may be connected in parallel to the positive electrode tab of the electrode assembly.

4 and 5, the (+) and (-) poles of the piezoelectric element can be directly connected in parallel to the positive and negative electrode tabs of the jelly-roll type electrode assemblies 420 and 520, respectively have.

As described above, the present invention is a cylindrical secondary battery having a structure in which a piezoelectric element is included in a jelly-roll type electrode assembly and / or a battery case. When the jelly-roll type electrode assembly is inflated during the charging / discharging of the secondary battery, By applying pressure to the piezoelectric element, electrical energy can be produced as the potential difference is generated.

Since the expansion and contraction of the jelly roll type electrode assembly is repeatedly performed, pressure can be repeatedly applied to the piezoelectric element, so that the production of electric energy by the piezoelectric element can be repeatedly performed together with the charge / ≪ / RTI >

Hereinafter, embodiments of the present invention will be described, but it should be understood that the scope of the present invention is not limited thereto.

<Examples>

As shown in FIG. 2, a cylindrical secondary battery in which a lower surface of a battery case is composed of a single layer, and a side surface is composed of an outer case and an inner case having a hollow therein, and a hollow piezoelectric element is interposed therebetween.

The cylindrical rechargeable battery is a 18650 type battery having an outer diameter of 18 mm and a height of 65 mm, and the side height of the battery case with the piezoelectric element interposed except for the height of the cap assembly at the upper side is 60 mm.

The thickness of the battery case is 0.15 mm. When the thicknesses of the outer case, the inner case and the hollow are 0.05 mm, 0.05 mm and 0.05 mm, respectively, the volume of the portion where the piezoelectric element is interposed can be calculated as follows.

V = 3.14 x 18 mm x 0.05 mm x 60 mm x 1 cm 3/1000 cm = 0.16956 cm 3

In the case of the piezoelectric element, the energy density according to the pressure is usually 250 cd / cm 3, so that the energy of 250 ㎼ / cm 3 x 0.16956 cm 2 = 42.39 ㎼ = 0.4239 mW can be obtained in the case of the battery case.

As described above, in the case of using the cylindrical secondary battery according to the present invention, besides the energy generated by the electrical charging of the secondary battery, the electric energy can be produced according to the physical volume expansion of the electrode assembly, It is possible to provide a cylindrical secondary battery in which the energy density is improved without increasing the energy density.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

- Explanation of symbols

100: Cylindrical secondary battery

101, 200, 300: Battery case

110, 210, 310, 410, 510: piezoelectric element

120, 420, 520: electrode assembly

201, 301: outer case

202, 302: inner case

205, 305: the bottom surface of the battery case

As described above, the cylindrical rechargeable battery according to the present invention has a structure in which a piezoelectric element for generating electric energy by volume expansion due to charging and discharging of the jelly-roll type electrode assembly is added to the jelly-roll type electrode assembly or the battery case The present invention provides a secondary battery in which energy can be further generated in addition to the energy of the battery due to the charging of the bar and the cylindrical secondary battery, thereby remarkably improving the energy density.

The piezoelectric element according to the present invention has an effect of suppressing the charging / discharging of the electrode assembly, thereby preventing deformation of the electrode assembly due to charging and discharging.

In addition, since the electric energy generated by the self-power generation using the piezoelectric element is stored in the jelly-roll type electrode assembly, a separate storage space is not required, and when a storage space is separately required, The problem of lowering the energy density per unit volume as the volume increases can be solved.

Claims (13)

1. A jelly-roll type electrode assembly having a structure in which a separation membrane is interposed between a positive electrode and a negative electrode of a long sheet type;

   A cylindrical battery case for accommodating the jelly-roll type electrode assembly; And

   A piezoelectric element for generating electric energy by volume expansion due to charging / discharging of the jelly-roll type electrode assembly;

   And a cylindrical secondary battery.
2. The cylindrical secondary battery according to claim 1, wherein the piezoelectric element is positioned between the jelly-roll type electrode assembly and the cylindrical battery case.
3. The cylindrical rechargeable battery of claim 2, wherein the piezoelectric element is attached to a tape for preventing unwinding of the jelly-roll type electrode assembly.
4. The cylindrical secondary battery according to claim 2, wherein the piezoelectric element is attached to an inner surface of the cylindrical battery case.
5. The battery case according to claim 1, wherein the cylindrical battery case comprises an outer case and an inner case in which a hollow is formed,

   And the piezoelectric element is located in the hollow.
6. 6. The cylindrical rechargeable battery of claim 5, wherein the cylindrical battery case has a cylindrical structure with a double structure of an outer case and an inner case, and a bottom surface of the cylindrical case has a single structure.
7. The cylindrical secondary battery according to claim 1, wherein the piezoelectric element is at least one selected from the group consisting of natural piezoelectric materials, artificial piezoelectric crystals, lead-free piezoelectric ceramics, and artificial piezoelectric ceramics.
8. The method of claim 7, wherein the piezoelectric material is a natural nitro suberic Li (AlPO _4), sucrose, quartz, a syelyeom, topaz, tourmaline, silk, enamel or dentin, a cylindrical secondary battery.
9. The cylindrical secondary battery according to claim 7, wherein the artificial piezoelectric crystal is gallium phosphide (GaPO ₄ ) or langasite (La ₃ Ga ₅ SiO ₁₄ ).
10. The cylindrical secondary battery according to claim 7, wherein the lead-free piezoelectric ceramics is NaKNb, bismuth oxide (BiFeO ₃ ), sodium niobium oxide (NaNbO ₃ ), Bi ₄ Ti ₃ O ₁₂ or Na _0.5 Bi _0.5 TiO ₃ .
11. The method of claim 7, wherein the artificial piezoelectric ceramics is one selected from the group consisting of BaTiO ₃ , NbTiO ₃ , KNbO ₃ , LiNbO ₃ , A cylindrical secondary battery comprising lithium tantalum oxide (LiTaO ₃ ), sodium tungstate (Na ₂ WO), zinc oxide (ZnO ₃ ), Ba ₂ NaNb ₅ O ₅ , and Pb ₂ KNb ₅ O ₁₅ .
12. The cylindrical rechargeable battery of claim 1, wherein the electric energy generated by the piezoelectric element is stored in the jelly-roll type electrode assembly.
13. 13. A battery pack comprising the cylindrical secondary battery according to any one of claims 1 to 12.

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