KR102508855B1 - Palnar secondart battery stack - Google Patents

Abstract

A flat stack is provided. A plate-type stack according to the present invention is a plate-type unit stack in which a plurality of unit cells including a solid electrolyte, a cathode and an anode, and an upper cap and a lower cap are stacked, and disposed between the unit cells and the unit cells, A surface pressure applying unit for uniformly applying surface pressure to the sealing unit of the unit cell is included.

Description

Flat type secondary battery stack {PALNAR SECONDART BATTERY STACK}

The present invention relates to a flat-type secondary battery stack.

As the energy conversion policy that expands the proportion of eco-friendly and renewable energy generation in connection with the new and renewable energy market that is expanding worldwide is accelerating, various secondary batteries are being tested as secondary batteries for ESS (Energy Storage System).

As an example of a secondary battery for ESS, the sodium-nickel chloride (Na-NiCl ₂ ) battery is a secondary battery for ESS due to its excellent performance in key characteristics required by the ESS market for power storage, such as high safety, long lifespan, and high energy density. is receiving great attention.

However, since the sodium-nickel chloride battery operates at a high temperature of a set temperature (eg, 280 to 320 ° C), the speed of expansion of the large-capacity power storage market is expected due to stability and lifespan due to high-temperature operation and price issues in the manufacturing process. is not reaching

In particular, advanced bonding technologies such as thermal compression bonding (TCB), glass sealing, and laser welding are employed for bonding between dissimilar materials constituting batteries, and such high-cost bonding Adoption of the technology is an obstacle to further lowering the price of sodium-nickel-chloride batteries.

In order to dramatically lower the price of sodium-nickel chloride batteries, it is essential to develop technology that lowers the battery driving temperature to a set temperature (eg, 200° C.) or less by replacing the existing high-cost bonding process with an ultra-low-cost bonding process using a polymer.

In parallel, mass production is possible by applying a flat cell design that significantly reduces the number of parts and a one-step hot pressing cell manufacturing process that simplifies the existing multi-step manufacturing process. It is also necessary to establish a possible unit cell manufacturing process.

For module design, it is necessary to create a unit stack by stacking the unit cells in the vertical direction to connect them in series, including the mechanical bonding ability of the unit cells and the maintenance of electrical contact between the stacked unit cells. Therefore, it is necessary to have an appropriate surface pressure structure to secure structural stability.

In addition, a wiring connection technology is required to ensure a desired electrical output by connecting the manufactured unit stacks in series or parallel.

In addition, while maintaining the operating temperature of the battery, it is necessary to simultaneously consider the high-temperature stability problem of materials selected for mid-low temperature operation. For this purpose, specifications of heaters, coolers, insulation materials, etc. City temperature management technology is required.

As a temperature management method inside the module, first, it is necessary to secure an insulation structure to prevent cooling during storage rather than charging and discharging, and a fan is installed to manage the temperature inside the module when the temperature changes during charging and discharging. A method of causing forced convection is used.

In addition, in order to prevent rapid temperature rise due to damage or malfunction of unit cells or unit stacks, a separator made of an insulating material is placed between the unit stacks to prevent local temperature rises from spreading to the entire module in case of an emergency.

However, such a separator has a problem in that the internal flow is blocked and eventually the temperature management function by forced convection of the fan is weakened.

In this way, issues related to mechanical stability of a stack connecting cells in series in order to manufacture a medium-low temperature driving flat panel sodium-nickel chloride battery module are as follows.

In the case of a unit cell, constant sealing is maintained between the top cap of the cathode part and the solid electrolyte, and between the solid electrolyte and the bottom cap of the anode part. pressure must be applied.

If an individual surface pressure structure is used for each unit cell, when expanding to a unit stack, not only the volume and weight increase, but also the cost increases. Apply an integrated surface pressure structure to secure

However, in a stack module that connects a plurality of stack units, a loading framing technique is required to simplify the manufacturing process and more efficiently apply the required surface pressure.

In particular, if the upper cap of the cathode part and the lower cap of the anode part are manufactured by processing thick blocks, it will be advantageous to maintain the sealing state by smoothly transferring the surface pressure of the upper surface pressure structure to the sealing material part in the high-lamination stack, but machining As costs increase, it becomes difficult to secure economic feasibility.

In general, in order to secure economic feasibility of a secondary battery, an upper cap and a lower cap are manufactured by a thin plate molding method using a press. In this case, a problem in that the sealing structure is weakened due to deformation of the thin plate occurs.

An object of the present invention is to provide a flat-type secondary battery stack capable of securing a constant surface pressure at the sealing portion of the unit cell even when surface pressure is collectively applied from the top of the unit stack using loading framing.

A plate-type secondary battery stack according to an embodiment of the present invention includes a plurality of units in which a plate-type solid electrolyte and a plate-type cathode and anode respectively disposed on the upper and lower surfaces of the solid electrolyte are sealed by upper and lower caps. It may include at least one unit stack of a plate type in which cells are stacked.

The flat-type secondary battery stack may include a surface pressure applicator disposed between unit cells and uniformly applying surface pressure to sealing parts of the unit cells.

The sealing part of the unit cell may include a cathode sealing part and an anode sealing part disposed between the solid electrolyte and the upper cap and the lower cap, respectively.

The surface pressure applying unit may uniformly apply surface pressure to the cathode sealing unit and the anode sealing unit.

The surface pressure application unit may be formed of a coil spring or a wave spring inserted and coupled between a unit cell and a neighboring unit cell.

A coil spring or wave spring may be disposed coaxially with the unit cell.

The coil spring or wave spring may be disposed between an upper cap or lower cap of a unit cell and a lower cap or upper cap of a neighboring unit cell.

The upper cap may include an upper cap body disposed on the upper surface of the cathode and having a cylindrical shape, and an upper flange portion disposed on the upper surface of the cathode sealing part and elastically supporting the coil spring.

The upper flange portion may be formed in a thin plate shape by extending outwardly while stepping downward on the outer circumferential surface of the upper cap body.

The lower cap may include a lower cap body disposed on a lower surface of the anode and having a cylindrical shape, and a lower flange portion disposed on a lower surface of the anode sealing unit and elastically supporting the coil spring.

The lower flange portion may be formed in a thin plate shape by extending outwardly while stepping upward on an outer circumferential surface of the lower cap body.

The coil spring and the wave spring may have diameters larger than outer diameters of the upper cap body and the lower cap body.

The unit stack may be formed by vertically stacking a plurality of unit cells in series.

According to an embodiment of the present invention, the surface pressure of unit cells is relatively simply maintained, and in the case of configuring a stack by serially stacking unit cells, it is composed of a surface pressure structure (surface pressure applying unit) in units of stacks or a parallel connection of stacks. It becomes possible to maintain the desired surface pressure in the sealing material of the unit cell only with the surface pressure structure of the module unit.

Accordingly, it is possible to manufacture thin plate components instead of thick components (upper cap, lower cap), thereby reducing raw material costs and system weight, and by applying a low-cost process of the press method instead of mechanical processing, process costs can be reduced. can

1 is a schematic partial perspective view for explaining a stacked state of unit cells of a flat-type secondary battery stack according to a first embodiment of the present invention.
2 is a schematic partial cross-sectional view for explaining a surface pressure structure in a unit cell of a flat-type secondary battery stack according to a first embodiment of the present invention.
3 is an exploded perspective view showing a stacked state of one unit cell of the flat-type secondary battery stack according to the first embodiment of the present invention.
4 is an exploded perspective view showing a stacked state of two unit cells of a flat type secondary battery stack according to a first embodiment of the present invention.
5 is a perspective view of a unit stack in which a plurality of unit cells of a flat-type secondary battery stack according to a first embodiment of the present invention are vertically stacked.
6 is a schematic partial perspective view for explaining a stacked state of unit cells of a flat-type secondary battery stack according to a second embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described so that those skilled in the art can easily practice it. As can be easily understood by those skilled in the art to which the present invention pertains, the embodiments described below may be modified in various forms without departing from the concept and scope of the present invention. Where possible, identical or similar parts are indicated using the same reference numerals in the drawings.

The terminology used below is only for referring to specific embodiments and is not intended to limit the present invention. As used herein, the singular forms also include the plural forms unless the phrases clearly indicate the opposite. As used herein, the meaning of "comprising" specifies specific characteristics, regions, integers, steps, operations, elements and/or components, and other specific characteristics, regions, integers, steps, operations, elements, components and/or groups. does not exclude the presence or addition of

All terms including technical terms and scientific terms used below have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention belongs. The terms defined in the dictionary are additionally interpreted as having a meaning consistent with the related technical literature and the currently disclosed content, and are not interpreted in an ideal or very formal meaning unless defined.

1 is a schematic partial perspective view for explaining a stacked state of unit cells of a planar secondary battery stack according to a first embodiment of the present invention, and FIG. 2 is a planar secondary battery stack according to a first embodiment of the present invention. It is a schematic partial cross-sectional view for explaining the surface pressure structure in the unit cell of.

5 is a perspective view of a unit stack in which a plurality of unit cells of a flat-type secondary battery stack according to a first embodiment of the present invention are vertically stacked.

Referring to FIGS. 1, 2, and 5 , the planar secondary battery stack according to the first embodiment of the present invention includes a unit stack 20 in which a plurality of unit cells 10 are stacked, and a unit cell 10 It is inserted between and the unit cell 10, and may include a surface pressure applying unit 100 for applying a constant surface pressure to the sealing portion of the unit cell 10.

The unit cell 10 is a flat plate-shaped sodium secondary battery, which includes a substantially flat plate-shaped solid electrolyte 11, a circular plate-shaped cathode 13 disposed on the upper and lower surfaces of the solid electrolyte 11, respectively, and Anode 14 may be included.

The unit cell 10 is disposed above and below the cathode 13 and the anode 14, respectively, and the upper cap 15 and the lower cap 16 for covering the cathode 13 and the anode 14 with a sealing structure can include

In addition, the unit cell 10 is disposed between the solid electrolyte 11 and the cathode 13 to seal between the solid electrolyte 11 and the upper cap 15, the cathode sealing portion 17, and the solid electrolyte ( 11) and the anode 14, and may include an anode sealing part 18 for sealing between the solid electrolyte 11 and the lower cap 16.

The surface pressure applying unit 100 is a coil spring inserted and coupled between the unit cell 10 and the neighboring unit cell 10 so as to apply a constant surface pressure to the cathode sealing part 17 and the anode sealing part 18 ( 110) and the like.

In addition, the coil spring 110 may be coaxially disposed with the unit cell 10 so as to apply a constant surface pressure to the cathode sealing part 17 and the anode sealing part 18 of the unit cell 10 .

The coil spring 110 will be disposed between the upper cap 15 or lower cap 16 of one unit cell 10 and the lower cap 16 or upper cap 15 of the neighboring unit cell 10. can

1 shows a case where the coil spring 110 is disposed between the upper cap 15 and the neighboring lower cap 16 for convenience, but is not limited thereto, and the lower cap 16 and the neighboring upper cap ( 15), of course.

The upper cap 15 is disposed on the upper surface of the cathode 13 and is disposed on the upper surface of the upper cap body 151 having a cylindrical shape and the like, and the upper surface of the cathode sealing part 17 and elastically supported by the coil spring 110. A flange portion 153 may be included.

The upper flange portion 153 is formed in the form of a thin plate by extending outwardly while stepping downward on the outer circumferential surface of the upper cap body 151 so that the coil spring 110 can be firmly elastically supported while sealing the cathode sealing portion 17. can

In addition, the lower cap 16 is disposed on the lower surface of the anode 14 and is disposed on the lower surface of the lower cap body 161 having a cylindrical shape and the anode sealing part 18, and the coil spring 110 is elastically supported. A lower flange portion 163 may be included.

The lower flange portion 163 is formed in the form of a thin plate by extending outwardly while stepping upward on the outer circumferential surface of the lower cap body 161 so that the coil spring 110 can be firmly elastically supported while sealing the anode sealing portion 18. can

In addition, the coil spring 110 has a larger diameter than the outer diameters of the upper cap body 151 and the lower cap body 161 so as to easily apply surface pressure to the cathode sealing portion 17 and the anode sealing portion 18. , may have a smaller diameter than the outer diameter of the solid electrolyte 11.

The length of the coil spring 110 in the axial direction may be equal to or less than the height of the upper cap body 151 or the lower cap body 161 so as to minimize the stacking height of the unit cells 10.

Also, as shown in FIG. 5 , the unit stack 20 may be formed by vertically stacking a plurality of unit cells 10 in series.

Although 10 unit cells 10 are vertically stacked in the unit stack 20 of FIG. 5 , it is needless to say that 10 or more or less units may be stacked as needed.

3 shows a state in which one surface pressure applying unit 100 is applied, and FIG. 4 shows a state in which two surface pressure applying units 100 are applied, but it is not limited thereto, and a plurality of them can be applied as needed. Of course.

Hereinafter, with reference to FIGS. 1, 2, and 5, the operation of the flat-type secondary battery according to an embodiment of the present invention will be described.

Here, the coil spring 110 of the surface pressure applying unit 100 is inserted and coupled between the upper cap 15 of one unit cell 10 and the lower cap 16 of the neighboring unit cell 10.

That is, the lower end of the coil spring 110 is elastically supported on the upper surface of the upper flange portion 153 of the upper cap 15, and the upper end of the coil spring 110 is attached to the lower flange portion 163 of the lower cap 16. It is elastically supported on the bottom.

In this state, when surface pressure is applied from the top of the unit cell 10 to the bottom of the unit cell 10 using a loading frame (not shown), the surface pressure applied to the unit cell 10 in this way is applied to the upper cap ( 15) is applied to the upper surface and corner portion of the upper cap 151 and the lower surface and corner portion of the lower cap body 161 of the lower cap 16, respectively.

In addition, the surface pressure applied to the unit cell 10 is applied to the upper surface of the upper flange portion 153 of the upper cap 15 and the lower plane of the lower cap 16 through the coil spring 110 of the surface pressure applying unit 100. Each is applied to the lower surface of the branch 163 .

At this time, the surface pressure applied to the upper flange portion 153 through the lower end of the coil spring 110 is applied to the cathode sealing portion 17 disposed between the upper flange portion 153 and the solid electrolyte 11 to form the unit cell 10 ) in the vertical direction (Y direction in FIG. 2 ), surface pressure can be uniformly applied to the cathode sealing portion 17 by the coil spring 110 .

In addition, the surface pressure applied to the lower flange portion 163 through the upper end of the coil spring 110 is applied to the anode sealing portion 18 disposed between the lower flange portion 163 and the solid electrolyte 11 to form the unit cell 10 ) Since it is applied in the vertical direction (Y direction in FIG. 2), it is possible to apply a constant surface pressure to the anode sealing part 18 by the coil spring 110.

6 is a schematic partial perspective view for explaining a stacked state of unit cells of a flat-type secondary battery stack according to a second embodiment of the present invention.

The planar secondary battery stack according to the second embodiment of the present invention is the same as the planar secondary battery stack according to the first embodiment of the present invention, except for the details described below, so detailed description thereof will be omitted. .

This is a case in which a wave spring 120 is applied instead of the coil spring 110 as the surface pressure applying unit 100 of the flat-type secondary battery stack according to the second embodiment of the present invention.

The wave spring 120 can minimize the space inserted between the unit cell 10 and the neighboring unit cell 10, and can provide high elasticity while occupying a small installation space.

Although the present disclosure has been described through preferred embodiments as described above, the present invention is not limited thereto, and various modifications and variations are possible without departing from the scope of the claims described below. Those in the field will easily understand.

10: unit cell
11: solid electrolyte
15: top cap
16: lower cap
17: cathode seal
18: anode seal
20: unit stack
100: surface pressure applying unit
110: coil spring

Claims (12)

A plate-type solid electrolyte, at least one plate-type unit stack in which a plurality of unit cells are stacked in which a plate-type cathode and anode disposed on the upper and lower surfaces of the solid electrolyte are sealed with upper and lower caps, and
A surface pressure applying unit disposed between the unit cells and uniformly applying surface pressure to the sealing portion of the unit cell.
including,
The sealing part of the unit cell includes a cathode sealing part and an anode sealing part disposed between the solid electrolyte, the upper cap, and the lower cap, respectively,
The surface pressure applying unit uniformly applies surface pressure to the cathode sealing part and the anode sealing part,
The surface pressure applying unit is a flat-type secondary battery stack composed of a coil spring or a wave spring inserted and coupled between the unit cell and the neighboring unit cell. delete delete delete According to claim 1,
The coil spring or the wave spring is a flat-type secondary battery stack disposed coaxially with the unit cell. According to claim 5,
The coil spring or the wave spring is disposed between the upper cap or the lower cap of a unit cell and the lower cap or the upper cap of a neighboring unit cell. According to claim 6,
The upper cap includes an upper cap body disposed on an upper surface of the cathode and having a cylindrical shape, and an upper flange portion disposed on an upper surface of the cathode sealing part and elastically supporting the coil spring. According to claim 7,
The upper flange portion is stepped downward on the outer circumferential surface of the upper cap body and extends outwardly to form a flat plate-type secondary battery stack. According to claim 8,
The lower cap includes a lower cap body disposed on a lower surface of the anode and having a cylindrical shape, and a lower flange portion disposed on a lower surface of the anode sealing part and elastically supporting the coil spring. According to claim 9,
The lower flange portion extends outwardly while stepping upward on the outer circumferential surface of the lower cap body to form a flat plate-type secondary battery stack. According to claim 10,
The coil spring and the wave spring have a larger diameter than outer diameters of the upper cap body and the lower cap body. The method of any one of claims 1 and 5 to 11,
The unit stack is a flat-type secondary battery stack in which a plurality of unit cells are vertically stacked in series.

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