KR20160016006A - Method for Preparation of Battery Cell Using Induction Heating - Google Patents

Abstract

The present invention relates to a method to manufacture a battery cell of which electric insulating external member surrounds the outer surface of a cell case except for electrode terminal parts. The method includes: a step (a) of placing at least one battery cell in a hollow hole of a thermal contraction member as an electric insulating external member; a step (b) of inductively heating the thermal contraction member by a high frequency inducing device; and a step (c) of surrounding the outer surface of the cell case of the battery cell as the heated thermal contraction member is contracted.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of manufacturing a battery cell by induction heating,

The present invention relates to a method of manufacturing a battery cell by induction heating.

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

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

Generally, a secondary battery includes an electrode assembly composed of an anode, a cathode, and a separator interposed between the anode and the cathode. The electrode assembly is embedded or wrapped in a cell case of a metal can or a laminate sheet. , And the cell case is sealed. As described above, an operating circuit member, a protective circuit member, an external input / output terminal, and the like can be additionally mounted on the cell case sealed after the electrolytic solution is impregnated.

A label capable of displaying product information of the secondary battery is attached to the outer surface of the secondary battery manufactured as described above. Such a label also functions as an insulating material which is attached to the metal can-cell case to cut off the electrical connection.

As a process for attaching a label to an outer surface of a battery, a method of directly heating a heat shrinkable member by using a hot air heater or a heating device has been used.

Fig. 1 schematically shows a method of manufacturing a battery cell using a method of directly heating a heat-shrinkable member by using such a heating device or the like.

1, when the cylindrical battery cell 101 is directly heated by using a heating device (not shown) after positioning the cylindrical electric insulating heat shrinkable member 102 having a hollow therein, The heat-shrinkable member 102 is contracted to closely contact the cell case of the battery cell 101 to cover the battery cell 101.

However, such a process requires a certain period of time to increase the temperature of the heating apparatus or the like, and it has been difficult to uniformly adhere the heat shrinkable member as the temperature difference occurs.

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

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art and the technical problems required from the past.

The inventors of the present application have conducted intensive research and various experiments and have found that by using a high frequency induction device to wrap (tubing) the outer surface of a cell case equipped with a battery cell with an electrically insulating outer material, It is possible to shorten the time and simultaneously apply the present invention to a plurality of battery cells so that a battery cell having a uniform quality can be manufactured and it is possible to shorten the manufacturing process time and improve the quality, The present invention has been completed.

Accordingly, a method of manufacturing a battery cell according to the present invention is a method of manufacturing a battery cell in which an electrically insulating casing surrounds an outer surface of a cell case excluding electrode terminal portions,

Placing at least one battery cell in a hollow interior of the heat shrinkable member as an electrically insulating casing;

Heating the heat-shrinkable member by a high frequency induction device; And

Shrinking the heated heat shrinkable member to wrap the outer surface of the cell case of the battery cell;

As shown in FIG.

Therefore, in order to cover the outer surface of the cell case of the battery cell with the heat-shrinkable member, the method of manufacturing the battery cell according to the present invention is a method of directly heating the heat- As a result, the instantaneous temperature rise is possible, which can shorten the manufacturing process time of the battery.

Also, since the process of wrapping the outer surface of the battery cell by the single induction heating can be applied to a plurality of battery cells at the same time, it is possible to mass-produce the battery cells of uniform quality and improve the production efficiency.

The shape of the secondary battery is not particularly limited as long as the electrode assembly is connected to the electrode terminal of the battery case via the electrode tab. For example, the electrode assembly may be a jelly-roll type, a stack type, And a battery cell having the electrode assembly therein may be manufactured in the form of a cylindrical battery cell or a prismatic battery cell.

In the process (a), the battery cell located in the hollow interior of the heat-shrinkable member may be formed by connecting two or more battery cells in series to increase the capacity of the battery, can do.

Each of the battery cells includes an electrode assembly having a separator disposed between the positive electrode plate and the negative electrode plate, a cell case having a housing portion in which the electrode assembly is housed, and a cap assembly coupled to the cell case to seal the cell assembly.

In the process of manufacturing a battery cell according to the present invention, the heat shrinkable member may have various structures as long as it has a characteristic of contracting at a temperature higher than a predetermined temperature so as to operate mechanically according to a temperature change of the surrounding environment. For example, Circular, elliptical, quadrangular, triangular, and the like, but are not limited thereto.

In one specific example, the heat shrinkable member may be a circular or elliptical hollow structure with a horizontal cross section as a heat shrinkable tube.

In addition, the heat-shrinkable member may be made of transparent or translucent material of various colors.

The material of the heat shrinkable member is not particularly limited as long as it has a property of shrinking at a predetermined temperature or higher. Examples of the material include polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, ethylene propylene rubber, A combination of one or more materials selected from the group consisting of chloroprene rubber, styrene butadiene rubber, nitrile butadiene rubber, and Teflon.

The manufacturing process of the battery cell according to the present invention is based on an induction heating method using a high-frequency induction heating apparatus, not by shrinking the heat-shrinkable member by directly heating the heat-shrinkable member using a conventional heating apparatus. Induction heating using the high frequency induction heating apparatus is a principle in which a magnetic field is generated when an AC power is supplied to a heating coil, and a secondary current is induced on the surface of the heating target to generate heat in the resistance component of the metal. Specifically, when a high frequency is applied in the high frequency induction device, a magnetic field is generated around the heating target to induce a secondary current on the surface of the heating target. The skin effect of the current (a phenomenon in which a primary current flows only on the surface of the object) And the proximity effect (a phenomenon in which the direction of the secondary current induced in the heating body is opposite to that in the case where the current flows due to the attractive force between the two coils) And the heat loss regenerated by the concentration of the overcurrent heats the surface layer of the heating target. When the high-frequency induction heating apparatus is used, rapid heating is possible, and the efficiency is good. The degree of shrinkage and the thermal distribution can be adjusted to suit the application purpose by varying the applied frequency. When the heating coil and the heating target are separated by the refractory (Non-metallic water and magnetic field characteristics).

The frequency applied in such a high frequency induction heating apparatus may be selected in a suitable range in consideration of the type and thickness of the heat shrinkable member to be used, but it may be in the range of 10 kHz to 500 kHz, May be between 50 kHz and 450 kHz, and more specifically between 100 kHz and 400 kHz. If the frequency range is too low, induction heating may be difficult and the heating time may be increased if the heat shrinkable member is thick. If it is too high, the type and thickness of the heat shrinkable member are controlled to control It is not preferable because there is a problem that the range is limited.

The cell case of the battery cell used in the method for manufacturing a battery cell according to the present invention may be inductively heated by the frequency applied by the high frequency induction heating device and may be transferred to the heat shrinkable member. The heat-shrinkable member thus heated contracts to cover the outer surface of the cell case of the battery cell, thereby achieving a desired object. At this time, in order to achieve the above object more effectively, the cell case of the battery cell may be made of a metal material.

The temperature at which heat shrinkage of the heat shrinkable member is initiated may vary depending on the material of the heat shrinkable member and the configuration of the battery, but may range from 70 ° C to 250 ° C, and may be 100 ° C to 230 ° C , More specifically from 120 ° C to 200 ° C. This is because a heating temperature higher than a certain level is required due to the characteristics of a heat shrinkable member which is induction-heated by a high-frequency induction device, and if it is shrunk at a too low temperature, it is not easy to handle in a battery manufacturing process due to excessive heat shrinkage , It is undesirable because the electrode assembly may be damaged by heat in the process for heat shrinkage if it exhibits shrinkage at too high a temperature.

On the other hand, the shrinkage percentage of the heat shrinkable member is not particularly limited as long as it can be adhered to the battery cell due to immediate shrinkage in a short time. However, it may be shrunk by 50% or more based on the initial length due to heat generation, To 80% of the thickness of the heat-shrinkable member, and may be shrunk within the above-described range depending on the thickness of the heat-shrinkable member and the number of the battery cells.

The thickness of the heat-shrinkable member is not particularly limited, but may be selected within an appropriate range in consideration of the circumference of the battery cell to be tubed and the shrinkage percentage of the heat-shrinkable member, and may be 50 탆 to 500 탆. More preferably from 100 mu m to 400 mu m, and more specifically from 150 mu m to 300 mu m.

In the method of manufacturing a battery cell according to the present invention, the heat shrinkable member contracted to enclose the outer surface of the cell case of the battery cell surrounds the outer surface of the cell case except for the electrode terminal of the battery cell or the region where the external input / output terminal is formed Specifically, a structure in which the electrode terminal or a part of the upper surface where the external input / output terminal is formed, all or a part of the lower surface which is the opposite end of the upper surface, and all of the side surfaces excluding the upper surface and the lower surface.

Therefore, the length of the heat-shrinkable member before shrinkage may be 100% to 140%, more specifically 110% to 130%, based on the length in the longitudinal direction of the battery cell side. If the length of the heat-shrinkable member is too short, the entire outer surface of the cell case can not be wrapped, so that there is a risk of short-circuiting in relation to different electrode terminals and external circuits of other battery cells. , And it is difficult to stably fix the battery cell on the outer surface of the battery cell. Therefore, there is a problem in achieving the object of using an electrically insulating outer cover material. When the battery is too long, the heat- This can be a problem and is not desirable.

Such a secondary battery includes a plurality of battery cells used as a power source for a middle- or large-sized device requiring high temperature stability, long cycle characteristics, and high rate characteristics, And can also be used as a unit battery of a battery pack.

Specific examples of the device include a mobile electronic device, a wearable electronic device, an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV) An electric vehicle including the electric vehicle; An electric motorcycle including an electric bike (E-bike) and an electric scooter (E-scooter); An electric golf cart, and the like, but the present invention is not limited thereto.

As described above, in the method of manufacturing a battery cell according to the present invention, when the outer surface of a cell case equipped with a battery cell is covered with an electrically insulating outer material, by using a high frequency induction device, a rapid temperature rise is possible, Since the heat shrinkable member is contracted to wrap the outer surface of the battery cell case, it is possible to shorten the production time of the battery and simultaneously apply the same to a plurality of battery cells, , The quality of the battery can be improved while improving the manufacturing processability.

1 is a schematic view of a method of manufacturing a battery cell using a method of directly heating a heat-shrinkable member using a conventional heating device;
2 is a schematic view illustrating a method of manufacturing a battery cell using a method of induction heating a heat shrinkable member by a high frequency induction device according to an embodiment of the present invention;
3 is a top plan view of a battery pack structure with a heat shrinkable member according to an embodiment of the present invention; And
4 is a top plan view of a battery pack structure with a heat shrinkable member according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, but the present invention is not limited by the scope of the present invention.

2 schematically shows a method of manufacturing a battery cell using a method of induction heating a heat shrinkable member by a high frequency induction device according to an embodiment of the present invention.

Referring to FIG. 2, first, the battery cell 101 is positioned inside the hollow of the heat-shrinkable member 102, which is used as an electrically insulating casing. Although the battery cell 101 is shown as a cylindrical battery cell in FIG. 2, the same can be applied to a prismatic battery cell. The heat-shrinkable member 102 may have a cylindrical shape and may have a shape in which an upper surface where electrode terminals protrude and a lower surface that is an opposite end of the upper surface penetrate, and the lower surface may be a closed shape. In addition, since the outer surface of the cell case of the battery cell can be covered by heat shrinkage, the circumference of the heat-shrinkable member should have a larger diameter in consideration of the diameter or width of the battery cell 101. [

Next, when the induction heating is performed by the high frequency induction device, a current flows in the heating coil 110 located around the heat shrinkable member 102 to generate a magnetic field, and a secondary current flows along the surface of the heat shrinkable member 102 So that the heat-shrinkable member is instantaneously heated.

The shape of the heating coil 110 may vary depending on the external shape and shape of the heating target and the heating apparatus used. Specifically, the heating coil 110 may be formed in one rotation, multiple rotation, assembling type, plural type, continuous connection type, Can be. In addition to the forms shown in FIG. 2, there are also round, rectangulat, formed, pancake, and spiral-helical.

The heat-shrinkable member thus heated is contracted to cover the outer surface of the cell case of the battery cell, and thus the battery cell with the electrically insulating outer member can be manufactured through the above process.

FIGS. 3 and 4 schematically show a state in which a heat-shrinkable member is in close contact with an outer surface of a plurality of cylindrical battery cells and a prismatic battery cell by the method for manufacturing a battery cell of the present invention.

3 and 4 illustrate how the heat shrinkable member manufactured after placing two or more battery cells 201 and 301 in the hollow interior of the heat shrinkable members 202 and 302 in the above- The front surface of the battery cell is schematically shown. As shown in these drawings, due to the shrinkage of the heat shrinkable members 202 and 302, the battery cells 201 and 301 must be densely packed so that the battery cells 201 and 301 can be stably fixed, It is preferable to arrange such that it does not occur.

3, two cylindrical battery cells 201 are arranged side by side in the lateral direction, and then the heat-shrinkable member 202 is contracted so as to surround the heat-shrinkable member 202, And also surrounds a portion excluding the portion where the electrode terminal 230 protrudes. Therefore, it is possible to prevent a short circuit due to contact of other electrodes or external circuits of other cells, so that the safety of the battery can be further improved.

4, four rectangular battery cells 301 are positioned so as to be two rows of two types, and then the heat shrinkable member 302 is contracted so as to surround the heat shrinkable member 302, 301), as well as a portion excluding the portion where the electrode terminal 330 protrudes. The heat-shrinkable member may surround not only the upper surface where the electrode terminals protrude but also the lower surface. When the heat-shrinkable member, which is the heat-shrinkable member, is covered with the bottom surface, the bottom surface may be entirely enclosed. Therefore, it is possible to prevent a short circuit due to contact of other electrodes or external circuits of other cells, so that the safety of the battery can be further improved.

Hereinafter, the present invention will be described in further detail, but the scope of the present invention is not limited thereto.

<Examples>

Two cylindrical battery cells including a jelly-roll type electrode assembly in which an anode, a separator, and a cathode were successively laminated, an electrically insulating heat-shrinkable tube, and a high-frequency induction device were prepared.

The heat-shrinkable tube has an open-ended cylindrical shape with a thickness of 100 占 퐉 and hollow, and is made of polyethylene terephthalate (PET).

Two cylindrical battery cells were placed inside the hollow of the heat-shrinkable tube, and a frequency of 100 kHz was applied to the heat-shrinkable tube by a high frequency induction device to induction-heat the tube. The heat-shrinkable tube was inductively heated and contracted by an applied frequency to obtain a battery cell having an outer casing of electrically insulating property on the outer surface of the cell casing of the battery cell.

<Comparative Example>

Two cylindrical battery cells including a jelly-roll type electrode assembly which was completed by successively stacking an anode, a separator, and a cathode, an electrically insulating heat-shrinkable tube, and a hot air blower were prepared.

The heat-shrinkable tube has an open-ended cylindrical shape with a thickness of 100 占 퐉 and hollow, and is made of polyethylene terephthalate (PET).

Two cylindrical battery cells were placed in the hollow of the heat-shrinkable tube, and the heat-shrinkable tube was directly heated by blowing hot air of 100 degrees for 5 seconds after inserting it into the hot air. The heat-shrinkable tube was heated and contracted by hot air at a high temperature to obtain a battery cell having an outer casing of electrically insulating property on the outer surface of the cell casing of the battery cell.

Comparing the battery cells obtained as a result of the examples and the comparative example, the battery cells according to the embodiments can instantaneously be heated by using the high-frequency induction device, and the heat-shrinkable tubes are shrunk within 0.5 seconds. The manufacturing process can be shortened by at least 10 times as compared with the manufacturing method, and the heat shrinkage can be more effectively performed by uniformly heating the inner surface of the heat-shrinkable tube opposite to the cell case by adjusting the applied frequency. Therefore, it can be seen that the battery cells according to the embodiments completely surround the outer surfaces of the two cylindrical battery cells in a heat-shrinkable tube.

On the other hand, since the battery cell according to the comparative example has a relatively long heating time, the heat shrinkable tube can not be heated to a uniform temperature up to the inside facing the cell case of the heat shrinkable tube, and the heat shrinkage can not be effectively performed. Therefore, the battery cells according to the comparative example can be confirmed that the heat-shrinkable tube is not completely adhered to the outer surfaces of the battery cells, but partially lifted.

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.

Claims (17)

A method of manufacturing a battery cell in which an electrically insulating jacket surrounds an outer surface of a cell case excluding electrode terminal portions,
(A) placing at least one battery cell in a hollow interior of the heat shrinkable member as an electrically insulating casing;
(B) a step of induction heating the heat-shrinkable member by means of a high frequency induction device; And
A step (c) of shrinking the heated heat-shrinkable member to wrap the outer surface of the cell case of the battery cell;
And forming a battery cell. The method of claim 1, wherein the battery cell is a cylindrical battery cell or a prismatic battery cell. The method according to claim 1, wherein, in the step (a), at least two battery cells are located in the hollow of the heat-shrinkable member. The method for manufacturing a battery cell according to claim 1, wherein the heat shrinkable member is a heat-shrinkable tube. The method according to claim 1, wherein the heat-shrinkable member is made of a transparent or semi-transparent material. The heat shrinkable member according to claim 1, wherein the heat shrinkable member is selected from the group consisting of polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, ethylene propylene rubber, isoprene rubber, chloroprene rubber, styrene butadiene rubber, nitrile butadiene rubber, Wherein the battery cell is made of one or more materials. The method of claim 1, wherein the frequency applied to the high frequency induction heating device is in the range of 10 kHz to 500 kHz. The method of claim 1, wherein the cell case of the battery cell is made of a metal material. The method of claim 1, wherein in the step (b), the high-frequency induction apparatus induces the cell case of the battery cell, and the induction-heated heat is transferred to the heat-shrinkable member. The method for manufacturing a battery cell according to claim 1, wherein the heat shrinkable member starts heat shrinking at 70 to 250 ° C. The method of claim 1, wherein the heat shrinkable member is shrunk by 50% or more based on the initial length due to heat generation. The method for manufacturing a battery cell according to claim 1, wherein the thickness of the heat-shrinkable tube is 50 to 500 탆. The method of claim 1, wherein the length of the heat shrinkable member is 100% to 140% based on a length of a side surface of the battery cell in a long axis direction. A battery cell characterized by being manufactured by the method according to any one of claims 1 to 13. A battery pack comprising the battery cell according to claim 14. A device comprising the battery pack according to claim 15 as a power source. 17. The device of claim 16, wherein the device is a mobile electronic device, a wearable electronic device, 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. &Lt; RTI ID = 0.0 &gt; 8. &lt; / RTI &gt;

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