KR20230045576A - Battery Cell, Battery Module, And Method For Manufacturing Battery Cell - Google Patents

Abstract

The present invention relates to a battery cell, a battery module, and a method for manufacturing the battery cell. Specifically, the battery cell may comprise: a cell case having an accommodating space; an electrode assembly having a plurality of electrode plates and separators alternately stacked and stored in the accommodating space; an electrode tab extending outward from the electrode plate and electrically connecting the electrode plate and an external terminal; a gel electrolyte accommodated in the accommodating space while surrounding the electrode tab to prevent movement of the electrode tab; and a liquid electrolyte accommodated in the accommodating space to surround the other side of the electrode assembly on which the electrode tab is not formed. Accordingly, flow and deformation of the electrode tab can be minimized by the semi-solid gel electrolyte.

Description

Battery cell, battery module, and method for manufacturing a battery cell {Battery Cell, Battery Module, And Method For Manufacturing Battery Cell}

The present invention relates to a battery cell, a battery module, and a method for manufacturing a battery cell, and more particularly, to a battery cell, a battery module, and a method for manufacturing a battery cell with improved durability without deterioration of battery performance.

Current commercially available secondary batteries include nickel cadmium batteries, nickel hydride batteries, nickel zinc batteries, lithium secondary batteries, and the like. Lithium secondary batteries do not have a memory effect compared to nickel-based secondary batteries, so they can be freely charged and discharged. In addition, lithium secondary batteries are in the limelight due to their very low self-discharge rate and high energy density.

Lithium secondary batteries mainly use lithium-based oxides and carbon materials as cathode and anode active materials, respectively. A lithium secondary battery includes a positive electrode plate coated with a positive electrode active material and a negative electrode active material on each current collector, an electrode assembly in which a negative electrode plate and a separator interposed therebetween are sequentially stacked, an electrolyte, and the electrode assembly and the electrolyte are sealed and stored together. It is made of outer material.

In addition, the lithium secondary battery may be classified into a can-type secondary battery and a pouch-type secondary battery according to the type of exterior material. In the can-type secondary battery, an electrode assembly is embedded in a metal can. In a pouch-type secondary battery, an electrode assembly is built into a pouch made of a soft polymer material having an irregular shape, for example, an aluminum laminate sheet pouch.

On the other hand, as lithium secondary batteries have recently been widely used in small-sized devices such as portable electronic devices as well as medium-large devices such as automobiles and power storage devices, research to increase the capacity and output of lithium secondary batteries has emerged. Pouch-type secondary battery cells, in which a large number of battery cells are easily stacked, are used in such medium- or large-sized devices.

Meanwhile, an electrode tab is formed on at least one side of a metal foil used for the positive electrode current collector and the negative electrode current collector. The electrode tab has a bent shape during a welding process between electrode leads.

These electrode tabs are relatively weak in mechanical strength due to their very thin thickness, and when finely folded and unfolded operations of the electrode tabs are repeated, disconnection of the electrode tabs may easily occur due to external impact. The disconnection of the electrode tab causes the capacitance of the connected electrode to be non-expressed, resulting in a deterioration in charge/discharge performance of the secondary battery cell during use. In particular, in the case of a pouch-type secondary battery cell provided in a vehicle pack, since it is exposed to frequent vibrations and shocks, there is a problem in that the lifespan of the battery cell is rapidly shortened. In addition, as current collectors are made thinner to increase the energy density of battery cells, the mechanical rigidity of electrode tabs also deteriorates, resulting in frequent disconnection at the bent part of the electrode tab or the connection between the electrode tab and the electrode. is happening Furthermore, since the width of the electrode tab is narrow and the length of the tab is shortened as the battery cell is miniaturized, when the battery cell is subjected to an external impact, the disconnection of the electrode tab is more likely to occur.

Therefore, there is a demand for developing a structure for a new pouch-type secondary battery cell capable of preventing disconnection of an electrode tab upon external impact.

Korean Patent Registration No. 10-1453781 Korean Patent Registration No. 10-0558843 Korean Patent Publication No. 10-2018-0082752 Japanese Patent Publication No. 2020-057502

The present invention provides a battery cell with improved durability without deterioration of battery performance, a battery module, and a method for manufacturing a battery cell.

According to one aspect of the present invention, the battery cell includes a cell case having an accommodation space; an electrode assembly in which a plurality of electrode plates and separators are alternately stacked and accommodated in the accommodation space; an electrode tab extending outward from the electrode plate and electrically connecting the electrode plate and an external terminal; a gel electrolyte accommodated while surrounding the electrode tab in the accommodation space to prevent movement of the electrode tab; and a liquid electrolyte accommodated in the accommodation space so as to surround the other side of the electrode assembly on which the electrode tab is not formed.

In one embodiment, the gel electrolyte may be located only in a peripheral area of the electrode tab, and the liquid electrolyte may be accommodated in the remaining space not filled with the gel electrolyte among the accommodation spaces.

According to another form of the present invention, the battery module may include at least one or more of the battery cells.

According to another aspect of the present invention, a method of manufacturing a battery cell includes preparing an electrode assembly having a plurality of electrode plates having an electrode tab formed on at least one side, and a separator interposed between the electrode plates. ; disposing the electrode assembly in the receiving space of the pouch; injecting the curable electrolyte composition into the receiving space of the pouch through the injection space of the pouch so as to surround the electrode tab; preventing the electrode tab from flowing by changing the curable electrolyte composition into a gel electrolyte; and injecting a liquid electrolyte into the accommodation space so as to surround the other side of the electrode assembly on which the electrode tab is not formed.

In another embodiment, the curable electrolyte composition may include a curable compound in an amount of 3 wt % to 30 wt %.

In another embodiment, before the step of injecting the curable electrolyte composition, the step of forming a blocking portion configured to block the curable electrolyte composition from moving from the accommodation space to the injection space may be further included.

In another embodiment, the forming of the blocking portion may include extending the blocking portion from an outer circumferential portion of the pouch along a boundary between the accommodation space and the injection space and extending the electrode assembly from one side end of the electrode assembly where the electrode tab is located. It may include a step of forming to further protrude toward the inside of.

In another embodiment, the forming of the blocking part may include melting bonding a portion between the injection space and the accommodation space of the pouch, or pressurizing a portion between the accommodation space and the injection space of the pouch. Formation may be included.

In another embodiment, before changing the curable electrolyte composition into a gel electrolyte to prevent the electrode tab from flowing, the pouch and the electrode assembly are pressurized and fixed using a jig plate outside the pouch to A step of fixing the shape of the curable electrolyte composition may be further included.

The step of preventing the electrode tab from flowing by changing the curable electrolyte composition into a gel electrolyte may be performed in a state in which the pouch and the electrode assembly are pressurized and fixed.

In another embodiment, the step of injecting the curable electrolyte composition may include disposing the pouch and the electrode assembly so that the electrode tab is positioned below the electrode assembly, and the curable electrolyte composition is applied to the electrode tab by using gravity. It may include a step of enclosing.

In another embodiment, the method may further include rotating the pouch so that the electrode tab is located on the side of the electrode assembly before the liquid electrolyte is injected.

The battery cell of the present invention accommodates a gel electrolyte in an area where an electrode tab is formed and a liquid electrolyte in an electrode assembly area where an electrode tab is not formed, thereby preventing the electrode tab from moving when an external impact is applied to the battery cell. Deformation of the electrode tab can be reduced. Therefore, when the battery cell of the present invention is mounted and applied to a vehicle, even if frequent shocks and vibrations generated during movement are transmitted to the battery cell, the flow and deformation of the electrode tab can be minimized by the gel electrolyte in a semi-solid state. .

Moreover, the battery cell of the present invention can prevent electric charge and discharge of the electrode from being deactivated due to disconnection of the electrode tab due to frequent flow of the electrode tab. In addition, the battery cell of the present invention can minimize damage to the electrode tab even when an external impact is applied by accommodating the gel polymer electrolyte, and also can effectively improve cycle characteristics by lowering the internal resistance of the battery by using a liquid electrolyte together.

In addition, according to another embodiment of the present invention, the manufacturing method of the present invention further includes forming a blocking portion inside the pouch before the curable electrolyte composition is injected, so that the curable electrolyte composition injected into the accommodation space is cured before curing. It can be prevented from moving from the accommodation space to the injection space. As described above, in the manufacturing method of the present invention, it is easy to maintain a state in which the curable electrolyte composition is disposed so as to cover the electrode tab until the curing step by the blocking part, so that manufacturing processability can be greatly improved.

1 is a plan view showing a battery cell according to an embodiment of the present invention.
2 is an exploded perspective view showing a pouch and an electrode assembly of a battery cell according to an embodiment of the present invention.
3 is an exploded perspective view showing a plurality of electrode plates and a separator according to an embodiment of the present invention.
4 is a vertical cross-sectional view showing the inside of a battery cell according to an embodiment of the present invention.
5 is a plan view showing the inside of a battery cell according to an embodiment of the present invention.
6 is a plan view showing the inside of a battery cell according to another embodiment of the present invention.
7 is a front view showing a state after an electrode assembly is inserted into an accommodation space of a pouch in a method of manufacturing a battery cell according to another embodiment of the present invention.
8 is a front view showing the inside of a pouch in which a curable electrolyte composition is injected into an accommodation space in a method for manufacturing a battery cell according to another embodiment of the present invention.
9 is a front view showing the inside of a pouch in which a curable electrolyte composition disposed around an electrode tab in an accommodation space is thermally cured in a method for manufacturing a battery cell according to another embodiment of the present invention.
10 is a front view showing the inside of a pouch in which a curable electrolyte composition disposed around an electrode tab in an accommodation space is UV-cured in a method of manufacturing a battery cell according to another embodiment of the present invention.
11 is a front view showing the inside of a pouch in which a gel electrolyte is accommodated around an electrode tab in an accommodation space in a method of manufacturing a battery cell according to another embodiment of the present invention.
12 and 13 are side views showing before and after fixing a battery cell using a fixing jig while a curable electrolyte composition is cured in a method for manufacturing a battery cell according to another embodiment of the present invention.
14 is a perspective view showing a state of a blocking member that presses a portion between an accommodation space and an injection space of a pouch in a method of manufacturing a battery cell according to another embodiment of the present invention.
15 is a perspective view showing a state in which a portion between an accommodation space and an injection space of a pouch is pressed using a blocking member in a method for manufacturing a battery cell according to another embodiment of the present invention.
16 is a perspective view showing the inside of a pouch in which a liquid electrolyte is injected into an accommodation space in a method of manufacturing a battery cell according to another embodiment of the present invention.
17 is a front view showing a state in which one side of an accommodation space of a pouch is additionally sealed in a method of manufacturing a battery cell according to another embodiment of the present invention.
18 is a front view showing a state in which an injection space of a pouch is removed in a method of manufacturing a battery cell according to another embodiment of the present invention.
19 is a front view showing a step of primarily injecting a curable electrolyte composition in a method for manufacturing a battery cell according to another embodiment of the present invention.
20 is a front view showing a step of primary curing a curable electrolyte composition in a method for manufacturing a battery cell according to another embodiment of the present invention.
21 is a front view showing a step of secondary injecting a curable electrolyte composition in a method for manufacturing a battery cell according to another embodiment of the present invention.
22 is a front view showing a step of secondary curing a curable electrolyte composition in a method for manufacturing a battery cell according to another embodiment of the present invention.
23 is a perspective view showing a battery module according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to the drawings. In describing the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the gist of the present invention, a detailed description thereof will be omitted. In addition, the following examples may be modified in many different forms, and the scope of the technical idea of the present invention is not limited to the following examples. Rather, these embodiments are provided to make this invention more thorough and complete, and to fully convey the spirit of the invention to those skilled in the art.

It should be understood that the techniques described herein are not intended to be limited to particular embodiments, but include various modifications, equivalents, and/or alternatives of the embodiments of the present invention.

In connection with the description of the drawings, like reference numerals may be used for like elements.

In the present invention, expressions such as "has", "can have", "includes" or "may include" indicate the existence of a corresponding feature (eg, numerical value, function, operation, or component such as a part). indicated, and does not preclude the presence of additional features.

In the present invention, expressions such as "A or B", "at least one of A and/and B" or "one or more of A or/and B" may include all possible combinations of the items listed together. For example, “A or B,” “at least one of A and B,” or “at least one of A or B” (1) includes at least one A, (2) includes at least one B, or ( 3) It may refer to all cases including at least one A and at least one B.

1 is a plan view showing a battery cell 100 according to an embodiment of the present invention. 2 is an exploded perspective view showing the pouch 114 and the electrode assembly 120 of the battery cell 100 according to an embodiment of the present invention. 3 is an exploded perspective view showing a separator 170 and electrodes 122 according to an embodiment of the present invention. Figure 4 is a vertical cross-sectional view showing the inside of the battery cell 100 according to an embodiment of the present invention. And, Figure 5 is a plan view showing the inside of the battery cell 100 according to an embodiment of the present invention. For reference, the gel electrolyte 150 and the liquid electrolyte 160 are omitted in FIG. 2 for convenience of description. In addition, in FIG. 5 , for convenience of explanation, a state in which the first cell sheet 114T is removed from the battery cell 100 of FIG. 1 is shown.

First, referring to FIG. 1, the battery cell 100 according to an embodiment of the present invention includes an electrode assembly (not shown) and a cell case 110 containing an electrolyte and a cathode lead 130a connected to a cathode tab (not shown). ), and an electrode lead 130 including a negative electrode lead 130b connected to a negative electrode tab (not shown). In addition, the cell case 110 may have a sealing portion 111 heat-sealed on the outer periphery.

Specifically, referring to FIGS. 1 to 5 , the cell case 110 includes an accommodation space 110p1 accommodating the electrode assembly 120, the electrode tab 121, the gel electrolyte 150, and the liquid electrolyte 160. ) may be included. The receiving space 110p1 may be a portion deformed into a cup shape by pressing a portion of at least one of the two cell sheets 114T and 114P with a high-temperature hot press. The accommodation space 110p1 may be a portion P in which a portion of each of the cell sheets 114T and 114P convexly protrudes outward.

The accommodating space 110p1 of the cell case 110 may have a size or larger enough to accommodate all of the plurality of electrode plates 122, the separator 170, the gel electrolyte 150, and the liquid electrolyte 160. . For example, as shown in FIG. 2 , the accommodating space 110p1 of the cell case 110 includes a convexly protruding portion P of the first cell sheet 114T upward, and a second cell sheet 114P. ) The portions R formed concavely in the lower direction may be formed by being coupled to each other.

Meanwhile, the cell case 110 may be a pouch-type case made of a soft material. The cell case 110 is combined with the first cell sheet 114T covering the upper part of the electrode assembly 120 and a part of the lower surface of the first cell sheet 114T, and the lower part of the electrode assembly 120 A second cell sheet 114P covering may be provided. Each of the first cell sheet 114T and the second cell sheet 114P may be a laminate sheet. Specifically, the laminate sheet may have a structure in which a thin metal film (eg, Al film) is laminated between a water-resistant polymer film (nylon) and a thermal bonding polymer film (eg, cast polypropylene). Since the structure of the laminate sheet and materials constituting each layer are widely known in the art to which the present invention pertains, a detailed description thereof will be omitted.

To seal the cell case 110, portions of each of the first cell sheet 114T and the second cell sheet 114P may be heat-sealed to each other. The heat-sealing method includes pressing at least a portion of the outer circumference of each of the first cell sheets 114T and the second cell sheet 114P facing each other with a high-temperature tool (eg, hot press) in a stacked state. can include At this time, the heat-sealing temperature may be 110 degrees Celsius to 150 degrees Celsius. For example, as shown in FIG. 1 , the cell case 110 may have a heat-sealed sealing portion 111 formed on the outer periphery.

In addition, as shown in FIG. 3 , the electrode plates 122 may be at least one anode 122p and at least one cathode 122n according to electrical polarities. The electrode plate 122 may include a current collector (not shown), an electrode active material coated on the current collector, a conductive material, and a mixture M1 of a binder. The current collector may be an aluminum alloy foil or a copper alloy foil. For example, the positive electrode 122p may be formed by applying a mixture of a positive electrode active material, a conductive material, and a binder to a current collector made of aluminum alloy. The anode 122n may be formed by applying a mixture M2 of an anode active material, a conductive material, and a binder to a copper alloy current collector. Also, a separator 170 may be interposed between the positive electrode 122p and the negative electrode 122n. The separator 170 may serve to block an internal short circuit between the positive electrode 122p and the negative electrode 122n and impregnate the electrolyte. The separator 170 of the present invention may be used without particular limitation as long as it is a separator material commonly used in secondary batteries. For example, the separator 170 may be made of at least one of polyethylene and polypropylene. In addition, the positive electrode 122p, the separator 170, and the negative electrode 122n may be sequentially stacked to form the electrode assembly 120.

A mixture of the electrode active material, the conductive material, and the binder may not be applied to the electrode tab 121 shown in FIG. 2 . The electrode tab 121 may be a path through which electrons may move. The electrode tab 121 may be formed by cutting the uncoated portion not coated with the positive electrode active material, or may be formed separately by connecting a separate conductive member to the uncoated portion of the electrode plate 122 by ultrasonic welding or the like. For example, as shown in FIG. 3 , electrode tabs 121 protruding from the first side 122n1 may be provided on each of the anode 122p and the cathode 122n. However, it is not necessarily limited to this form. For example, the electrode tab 121 may be formed on one or more of a first side, a second side, a third side, and a fourth side of the electrode 122 in each direction. For example, as shown in FIG. 3 , when the positive electrode 122p has a rectangular shape in plan, the positive electrode tab 121a has a first side 122p1 , a second side 122p2 , and a third side 122p3 . ), and may be formed on any one or more of the fourth side 122p4. In addition, when the negative electrode 122n has a quadrangular shape in plan, the negative electrode tab 121b has a first side 122n1 , a second side 122n2 , a third side 122n3 , and a fourth side 122n4 . ) may be formed on any one or more of

As shown in FIG. 2 , the battery cell 100 according to an embodiment of the present invention may further include an electrode lead 130 coupled to a portion of the electrode tab 121 . The electrode lead 130 may be an electrically conductive metal. As shown in FIG. 2 , the electrode lead 130 may include a positive lead 130a connected to the positive tab 121a and a negative lead 130b connected to the negative tab 121b. The electrode lead 130 may be connected to one or more electrode tabs 121 by various methods such as welding. A portion of the electrode lead 130 may be disposed to be exposed to the outside of the cell case 110 . That is, the electrode lead 130 serves as an electrode terminal of the battery cell 100 . For example, the positive lead 130a may serve as a positive terminal of the battery cell 100, and the negative lead 130b may serve as a negative terminal of the battery cell 100. In addition, as shown in FIG. 4 , the battery cell 100 may include an insulating film 140 configured to cover a portion of the outer surface of the electrode lead 130 . The insulating film 140 may electrically insulate between the cell case 110 and the electrode lead 130 and may be configured to be heat-sealed to the cell case 110 .

Meanwhile, the gel electrolyte 150 shown in FIGS. 4 and 5 means an electrolyte having a gel phase. The gel electrolyte 150 may include a polymer cured to such an extent that the electrolyte exhibits a gel phase. That is, here, the gel phase can be referred to as semi-solid, and means maintaining a constant shape without flow in a steady state due to high viscosity.

In addition, the gel phase can be phenomenologically defined as a soft solid-like material containing one or more liquids. For example, the gel electrolyte 150 may include mostly liquid materials and some solid materials in terms of weight ratio. Specifically, the gel electrolyte 150 may be prepared by curing a curable compound mixed in the liquid electrolyte 160 and changing the phase to a gel-state electrolyte. The curable compound may include a heat curable compound (A) or an ultraviolet curable compound (B).

Specifically, as shown in FIGS. 4 and 5 , the gel electrolyte 150 is accommodated in the receiving space 110p1 of the cell case 110 so as to surround the electrode tab 121 . That is, the gel electrolyte 150 may be located on one side of the electrode assembly 120 where the electrode tab 121 is located in the accommodation space 110p1. The gel electrolyte 150 may be included in a form surrounding the outer surface of the electrode tab to prevent movement of the electrode tab 121 upon external impact. For example, as shown in FIG. 4 , the gel electrolyte 150 is formed between the inner surface of the accommodation space 110p1 and the first side 120a of the electrode assembly 120 where the electrode tab 121 is located. can be located At this time, the gel electrolyte 150 may cover the outer surfaces of each of the positive electrode tab 121a and the negative electrode tab 121b to prevent movement of each of the positive electrode tab 121a and the negative electrode tab 121b. there is. However, it is not necessarily limited to this form. For example, the electrode tab 121 may be at least one of the first side 120b, the second side 120b, the third side 120c, and the fourth side 120d of the electrode assembly 120. , the gel electrolyte 150 is applied to the first side 120b, the second side 120b, the third side 120c, and the fourth side 120b of the electrode assembly 120 where the electrode tab 121 is located. It may be located on any one or more of the sides 120d. In addition, the gel electrolyte 150 may be configured to cover the outer surface of the electrode tab 121 . In particular, the gel electrolyte 150 may be configured to surround a junction between the electrode tab 121 and the electrode lead 130 .

Also, the gel electrolyte 150 may be partially disposed on the other side of the electrode assembly 120 where the electrode tab 121 is not located. For example, the gel electrolyte 150 may be partially disposed on each of the second side 120b and the fourth side 120d of the electrode assembly 120 where the electrode tab 121 is not located.

Therefore, according to this configuration of the present invention, the battery cell 100, compared to the case where the liquid electrolyte 160 of the prior art battery cell surrounds the electrode tab, when an external impact is applied to the battery cell 100, Since the gel electrolyte 150 surrounds the electrode tab 121 , the gel electrolyte 150 prevents the electrode tab 121 from flowing, thereby reducing deformation. Accordingly, in the case of the battery cell 100 mounted in a vehicle, even if frequent shocks and vibrations generated during movement are transmitted to the battery cell 100, the semi-solid state of the gel electrolyte 150 Flow and deformation can be minimized.

Furthermore, the present invention can prevent disconnection of the connection portion between the electrode tab 121 and the electrode 122 or the bent portion of the electrode tab 121 due to frequent movement of the electrode tab 121, and thus disconnection It is possible to prevent the inactivation of the electrical charge and discharge of the electrode 122 due to . Furthermore, the battery cell 100 of the present invention can effectively extend the lifespan of the battery cell 100 by minimizing damage to the electrode tab 121 even when an external impact is applied.

Also, the liquid electrolyte 160 shown in FIGS. 4 and 5 means an electrolyte in a liquid state. The battery cell 100 according to an embodiment of the present invention can perform charging and discharging through ion exchange between the positive electrode 122p and the negative electrode 122n through the liquid electrolyte 160 . The liquid electrolyte 160 may be positioned between the positive electrode 122p and the negative electrode 122n to allow ions to move between the positive electrode 122p and the negative electrode 122n. In addition, the liquid electrolyte 160 may be located on the surface and pores of the separator 170 . When the battery cell 100 is a lithium secondary battery, a conventional non-aqueous electrolyte may be used as the liquid electrolyte.

In addition, the liquid electrolyte 160 may be accommodated in the accommodation space 110p1 to surround at least one other side of the electrode assembly 120 where the electrode tab 121 is not located. When the electrode tab 121 is positioned on the first side 120a of the electrode assembly 120, the liquid electrolyte 160 is applied to the second side 120b and the third side of the electrode assembly 120. (120c), and may be located on any one or more of the fourth side (120d). For example, as shown in FIG. 5 , when the electrode tab 121 is located on the first side 120a of the electrode assembly 120, the liquid electrolyte 160 is applied to the rest of the electrode assembly 120. It may be positioned to surround the second side 120b, the third side 120c, and the fourth side 120d.

According to this configuration of the present invention, when the liquid electrolyte 160 located between the electrodes 122 is consumed during charging and discharging of the battery cell 100, at least one of the electrodes 122 on which the electrode tabs 121 are not formed. The liquid electrolyte 160 located on one or more other sides may be moved between the electrodes 122 to replenish the liquid electrolyte 160 . Therefore, even if the liquid electrolyte 160 between the electrodes 122 is consumed after a plurality of charge/discharge cycles of the battery cell 100 , the decrease in lifespan of the battery cell 100 can be minimized.

Meanwhile, in the battery cell 100 of the present invention, the gel electrolyte 150 is filled only in the first side 120a of the electrode assembly 120 where the electrode tab 121 is located, and the electrode tab 121 is By disposing the liquid electrolyte 160 on as many other sides as possible among the remaining second side 120b, third side 120c, and fourth side 120d of the unformed electrode assembly 120, the liquid electrolyte 160 ) It is possible to secure the amount of liquid electrolyte 160 that can be replenished in preparation for consumption. Therefore, compared to surrounding the entire periphery of the electrode assembly 120 with the gel electrolyte 150, it is possible to effectively prevent the cycle characteristics of the battery cell 100 from deteriorating.

On the other hand, Figure 6 is a plan view showing the inside of the battery cell 100 according to another embodiment of the present invention.

Referring to FIG. 6 , in the battery cell 100 according to another embodiment of the present invention, compared to the battery cell 100 of FIG. 5 , the electrode tab 150 surrounds the electrode tab 121 . The liquid electrolyte 160 may be filled in the remaining space filled with the gel electrolyte 150 in the accommodation space 110p1.

In FIG. 6 , other components of the battery cell 100 except for the gel electrolyte 150 may be configured identically to those of FIG. 5 .

Specifically, when compared to the battery cell 100 of FIG. 5, the battery cell 100 of FIG. 6 is located in the accommodation space 110p1 located on one side of the electrode assembly 120 where the electrode tab 121 is located. The liquid electrolyte 160 may be filled in the space other than the peripheral area C adjacent to the electrode tab 121 . For example, in the gel electrolyte 150, after injecting the curable electrolyte composition into a small frame having an empty interior and surrounding the peripheral area C of the electrode tab 121, curing the curable electrolyte composition, , It can be formed by removing the small frame.

Therefore, in the battery cell 100 according to another embodiment of the present invention, the gel electrolyte 150 is formed only in the area C around the electrode tab 121, and the liquid electrolyte ( 160), the amount of the liquid electrolyte 160 accommodated in the accommodating space 110p1 of the cell case 110 can be increased. Accordingly, in the battery cell 100 of the present invention, even if the liquid electrolyte 160 is consumed in the electrode assembly 120 during charging and discharging, there is enough liquid electrolyte 160 in the accommodation space 110p1, so that the battery cell (100) has the advantage of minimizing the degradation of life.

7 is a front view showing a state after the electrode assembly is inserted into the receiving space of the pouch 114 in the manufacturing method of the battery cell 100 according to another embodiment of the present invention. 8 is a front view showing the inside of the pouch 114 in which the curable electrolyte composition 155 is injected into the receiving space 110p1 in the manufacturing method of the battery cell 100 according to another embodiment of the present invention. . For reference, in FIG. 8, the pouch 114 is shown transparently so that the inside of the pouch 114 can be seen from the outside for the purpose of drawing description.

Referring to FIGS. 7 and 8 together with FIGS. 4 and 5 , the present invention may provide a manufacturing method for manufacturing the battery cell 100 . A method of manufacturing a battery cell 100 according to an embodiment of the present invention includes inserting an electrode assembly 120, injecting a curable electrolyte composition 155, curing the curable electrolyte composition 155, and injecting the liquid electrolyte 160 . In one embodiment, the curable electrolyte composition 155 may be injected in a liquid state and then cured to undergo a phase change into the gel electrolyte 150 .

In one embodiment, the step of inserting the electrode assembly 120 includes electrodes 122 having an electrode tab 121 formed on at least one side, and a separator 170 interposed between the electrodes 122. A step of inserting the electrode assembly 120 into the receiving space 110p1 of the pouch 114 is included. Here, the pouch 114 may be referred to as a configuration of a stage before manufacturing the cell case 110 in which the accommodation space 110p1 is completely sealed. The pouch 114 may be formed by bonding outer peripheries of the first cell sheet 114T and the second cell sheet 114P to each other. An accommodation space 110p1 in which the electrode tab 121, the electrode assembly 120, the curable electrolyte composition 155, and the liquid electrolyte 160 can be accommodated may be formed in the pouch 114.

For example, the electrode tab 121 may be positioned on the first side 120a of the electrode assembly 120 . However, it is not necessarily limited to this form, and according to the manufacturing method according to another embodiment of FIGS. 19 to 21 described later, in the battery cell of the present invention, the electrode tab 121 is the electrode assembly 120 ) may be located on each of the first side 120a and the third side 120c. In this case, the gel electrolyte 150 may be disposed on each of the first side 120a and the third side 120c of the electrode assembly 120 in the accommodation space 110p1 of the pouch 114 . In this case, the liquid electrolyte 160 is formed between the electrode 122 and the separator 170, between the electrodes 122, and in the accommodation space 110p1 on the second side 120b of the electrode assembly 120. ) and the fourth side 120d.

Referring back to FIGS. 2, 5, and 7 , after the electrode assembly 120 is inserted, the first cell sheet 114T and the second cell sheet 114P are used to form the pouch 114. In a laminated state, each outer peripheral portion may be heat-sealed. For example, as shown in FIG. 7 , a sealing portion 111 may be formed on an outer periphery of the pouch 114 . The sealing part 111 heats the first outer circumferential portion 114a, the third outer circumferential portion 114c, and the fourth outer circumferential portion 114d of each of the first cell sheet 114T and the second cell sheet 114P to each other. It can be formed by fusing.

In one embodiment, as shown in FIG. 7 , at least one outer peripheral portion (corner) of the first cell sheet 114T and the second cell sheet 114P, for example, each second outer peripheral portion 114b ) may not fuse with each other. Accordingly, the second outer peripheral portions 114b of each of the first and second cell sheets 114T and 114P of the pouch 114 may be spaced apart from each other. In this way, the pouch 114 passes between the first outer peripheral portions 114a of each of the first and second cell sheets 114T and 114P that are not heat-sealed, and enters the accommodation space 110p1 with the curable electrolyte. The composition 155 or the liquid electrolyte 160 may be introduced.

Referring to FIG. 8 together with FIG. 3 , in the injection of the curable electrolyte composition 155, the curable electrolyte composition 155 containing the curable compound is injected into the space where the electrode tab 121 is located in the accommodation space 110p1. steps may be included. Here, the curable electrolyte composition may include a mixture of a curable compound in a liquid electrolyte. In addition, the curable compound may include a heat curable compound (A) or an ultraviolet curable compound (B). The curable electrolyte composition 155 may be a liquid electrolyte prior to curing, and may be configured such that the liquid electrolyte is changed into a gel phase electrolyte by curing the curable compound in a later step.

In addition, after injection, the curable electrolyte composition 155 may be disposed in the accommodation space 110p1 to cover the outer surface of the electrode tab 121 or to fill a gap between the electrode tabs 121 .

On the other hand, the liquid electrolyte, which is the main component constituting the curable electrolyte composition, is at least one lithium salt dissolved in a non-aqueous organic solvent, and a conventional non-aqueous electrolyte solution used in manufacturing a lithium secondary battery may be used.

Specifically, the lithium salt is LiPF ₆ , LiCl, LiBr, LiI, LiBF ₄ , LiClO ₄ , LiB ₁₀ Cl ₁₀ , LiAlCl 4 , LiAlO _{4 ,} LiCF ₃ SO ₃ , LiCH ₃ CO ₂ , LiCF ₃ CO ₂ , LiAsF ₆ , LiSbF ₆ , LiCH ₃ SO ₃ , LiN(SO ₂ CF ₃ ) ₂ (lithium bis(trifluoromethanesulfonyl)imide, LiTFSI), LiN(SO ₂ F) ₂ (Lithium bis(fluorosulfonyl)imide, LiFSI) and LiN(SO ₂ CF ₂ CF ₃ ) ₂ (lithium bisperfluoroethanesulfonimide, LiBETI) may include a single material or a mixture of two or more selected from the group consisting of, specifically, LiPF ₆ , LiBF ₄ , LiN(SO ₂ CF ₃ ) ₂ and LiN(SO ₂ F) ₂ It may include at least one selected from the group consisting of. The lithium salt may be appropriately changed within a generally usable range, but in order to obtain the optimum effect of forming a film for preventing corrosion on the electrode surface, the concentration of 0.8 M to 3.0 M, specifically 1.0 M to 3.0 M in the liquid electrolyte. can be included

Representative examples of the non-aqueous organic solvent include propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), vinylene carbonate (VC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), Dimethylsulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethylmethylcarbonate (EMC), and gamma butyrolactone (γ-butyrolactone ) may be one or more selected from the group consisting of However, the salt and the rising solvent of the liquid electrolyte 160 are not necessarily limited to the above-listed components, and similar effects may be obtained even when known components and equivalents thereof are applied.

In addition, the liquid electrolyte may further include other additives in order to further improve high-temperature output characteristics, high-temperature stability, overcharge prevention, and an effect of suppressing battery expansion at high temperatures. Such other additives include cyclic carbonate compounds such as vinylene carbonate (VC) or vinyl ethylene carbonate (VEC); halogen-substituted carbonate-based compounds such as fluoroethylene carbonate (FEC); 1,3-propane sultone (PS), 1,4-butane sultone, ethensultone, 1,3-propene sultone (PRS), 1,4-butene sultone or 1-methyl-1,3-propene sultone, etc. of sultone-based compounds; sulfate-based compounds such as ethylene sulfate (Esa), trimethylene sulfate (TMS) or methyltrimethylene sulfate MTMS); phosphate-based or phosphite-based compounds such as lithium difluoro(bisoxalato)phosphate, lithium difluorophosphate, lithium tetrafluorooxalato phosphate or tris(trimethylsilyl)phosphate; borate-based compounds such as tetraphenylborate, lithium oxalyldifluoroborate (LiODFB) or lithium bisoxalatoborate (LiB(C ₂ O ₄ ) ₂ , LiBOB); benzene-based compounds such as fluorobenzene; It may include at least one of a silane-based compound such as tetravinylsilane and a lithium salt-based compound such as LiPO ₂ F ₂ , LiSO ₃ F or LiBF ₄ . The other additives may be included in an amount of about 0.01 to 30% by weight, specifically 0.01 to 15% by weight, based on the total weight of the liquid electrolyte.

In addition, the heat-curable compound (A), which is one of the curable compounds, is a compound capable of gelating the curable electrolyte composition 155 by forming cross-links through a thermal polymerization reaction, and is a heat-curable compound used in conventional gel electrolyte production. The compound is not particularly limited, and specifically has a polymerizable functional group selected from the group consisting of a vinyl group, an epoxy group, an allyl group, and a (meth)acrylic group capable of causing a polymerization reaction in the structure, and is formed into a gel by polymerization or crosslinking. at least one of polymerizable monomers, oligomers, and copolymers that can be transformed into

More specifically, representative examples of the polymerizable monomer include tetraethylene glycol diacrylate, polyethylene glycol diacrylate (molecular weight of 50 to 20,000), and 1,4-butanediol diacrylate. 1,4-butanediol diacrylate, 1,6-hexandiol diacrylate, trimethylolpropane triacrylate, trimethylolpropane ethoxylate triacrylate ethoxylate triacrylate, trimethylolpropane propoxylate triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol tetraacrylate, pentaerythritol ethoxylate tetraacrylate Pentaerythritol ethoxylate tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, poly(ethylene glycol) diglycidylether, 1,5 -Hexadiene diepoxide (1,5-hexadiene diepoxide), glycerol propoxylate triglycidyl ether, vinylcyclohexene dioxide (vinylcyclohexene dioxide), 1,2,7,8-diepoxyoctane (1,2,7,8-diepoxyoctane), 4-vinylcyclohexene dioxide, butyl glycidyl ether, diglycidyl 1,2-cyclohexanedicarboxylate ( diglycidyl 1,2-cyclohexanedicarboxylate), ethylene glycol diglycidyl ether, glycerol triglycidyl ether, and glycidyl methacrylate. there is.

In addition, the above copolymers are representative examples thereof, such as PVDF-HFP (polyvinylidene-co-hexafluoropropylene), allyl 1,1,2,2-tetrafluoroethyl ether (TFE)-(2,2,2 -trifluoroethyl acrylate) copolymer, TFE-vinyl acetate copolymer, TFE-(2-vinyl-1,3-dioxolane) copolymer, TFE-vinyl methacrylate copolymer, TFE-acrylonitrile copolymers, TFE-vinyl acrylate copolymer, TFE-methyl acrylate copolymer, TFE-methyl methacrylate (MMA) copolymer and TFE-2,2,2-trifluoroethyl acrylate (FA) copolymer At least one of them may be mentioned.

On the other hand, when using the heat curable compound (A) as the curable compound, a polymerization initiator may be further included to induce heat curing.

The polymerization initiator is decomposed by heat in the battery, for example, 30 ° C to 100 ° C, or decomposed at room temperature (5 ° C to 30 ° C) to form radicals, and polymerizable monomers react by free radical polymerization. A gel electrolyte may be formed.

Representative examples of such polymerization initiators include benzoyl peroxide, acetyl peroxide, dilauryl peroxide, di-tert-butyl peroxide, t- Organic peroxides or hydroperoxides such as t-butyl peroxy-2-ethyl-hexanoate, cumyl hydroperoxide, hydrogen peroxide and 2, 2'-azobis (2-cyanobutane) (2,2'-azobis (2-cyanobutane)), 2,2'-azobis (methylbutyronitrile) (2,2'-azobis (methylbutyronitrile)) , Azo compounds such as AIBN (2,2'-azobis (iso-butyronitrile)) or AMVN (2,2'-azobisdimethylvaleronitrile) may be used.

The polymerization initiator may be included in an amount of 0.01 to 20 parts by weight, specifically 0.1 to 10 parts by weight, based on 100 parts by weight of the thermosetting compound (A). When the polymerization initiator is within the range of 0.01 to 20 parts by weight, the conversion rate of the curable compound can be increased to secure the properties of the gel electrolyte, and the pre-reaction can be prevented to improve the wetting property (wetting property) of the electrolyte solution for the electrode. there is.

In addition, the UV curable compound (B), which is one of the curable compounds, may include an UV curable acrylate monomer. The acrylate monomers are ODA (octyl/decyl acrylate), IDA (isodecyl acrylate), LA (lauyl acrylate), SA (stearyl acrylate), PEA (phenoxyethyl acrylate), MNPEOA (nonyl Phenol Ethoxylate Monoacrylate), Tetrahydrofurfuryl Acrylate, Cyclohexyl Acrylate, 4-Butylcyclohexyl Acrylate, Dicyclopentenyl Acrylate, Dicyclopentenyl Oxyethyl Acrylate, 4 -HBA (4-hydroxybutyl acrylate), and at least one selected from the group consisting of phenoxyethyl acrylate.

When using the UV curable compound (B) as the curable compound, a photopolymerization initiator may be further provided to induce photocuring of the curable compound.

Examples of the photopolymerization initiator include ethylbenzoin ether, isopropylbenzoin ether, α-methylbenzoin ethyl ether, benzoin phenyl ether, α-acyloxime ester, 1,1-dichloroacetophenone, 2-hydroxy-2- Methyl-1-phenylpropan-1-one, 1-hydroxycyclohexylphenyl ketone, anthraquinone, 2-anthraquinone, 2-chloroanthraquinone, thioxanthone, isopropyl thioxanthone, chlorothioxanthone, benzo It may include at least one of phenone, benzyl benzoate, or benzoyl benzoate.

Meanwhile, the curable electrolyte composition 155 may include a curable compound in an amount of 3wt% to 30wt% based on the total weight of the composition. When the content of the curable compound is less than 3 wt% based on the total weight of the curable electrolyte composition 155, it is difficult for the electrolyte composition to form a gel phase even when the curable compound is cured. In addition, when the content of the curable compound exceeds 30wt% with respect to the total weight of the gel electrolyte 150, the viscosity of the curable electrolyte composition 155 increases and the curable electrolyte composition 155 is injected into the battery cell 100. ) is poor, it may not be easy to move the curable electrolyte composition 155 to the accommodation space 110p1 where the electrode tab 121 is formed, and a part of the curable electrolyte composition 155 is moved while the electrode 122 ) is likely to remain between them. Since the curable electrolyte composition 155 remaining between the electrodes 122 has a higher ionic conductivity than the liquid electrolyte 160, it has a negative effect on the performance of the battery cell 100 (eg, an increase in battery internal resistance, etc.) can cause In one embodiment, the curable compound content of the curable electrolyte composition 155 may be 5wt% to 30wt% with respect to the total weight of the curable electrolyte composition. In one embodiment, the curable compound content of the curable electrolyte composition 155 may be from wt% to 25wt% with respect to the total weight of the curable electrolyte composition. Specifically, the content of the curable compound may be 8wt% to 20wt% based on the total weight of the curable electrolyte composition. More specifically, the content of the curable compound may be 13wt% to 30wt% based on the total weight of the curable electrolyte composition.

Meanwhile, referring again to FIG. 8 , according to the manufacturing method according to an embodiment of the present invention, an injection space 110p2 may be formed in the pouch 114 . Here, the injection space 110p2 is one side (upper side) of the accommodation space 110p1 in which the electrodes 122 are accommodated, among internal spaces formed between the first cell sheet 114T and the second cell sheet 114P. ) may be a space located in For example, an area from the open second outer peripheral portion 114b of the pouch 114 to the front of the accommodation space 110p1 may be set as the injection space 110p2. The injection space 110p2 may be configured to communicate with the accommodation space 110p1. The injection space 110p2 may serve as a passage through which the curable electrolyte composition 155 or the liquid electrolyte 160 may be moved to the accommodation space 110p1.

9 is a front view showing the inside of a pouch 114 in which a curable electrolyte composition 155 is thermally cured in an accommodation space 110p1 in a method for manufacturing a battery cell according to another embodiment of the present invention. For reference, in FIG. 9, the pouch 114 is shown transparently so that the inside of the pouch 114 can be seen from the outside for drawing description.

Referring to FIG. 9 , after the step of injecting the curable electrolyte composition 155 as in FIG. 8 , the pouch 114 is rotated so that the electrode tab 121 faces downward. That is, the curable electrolyte composition 155 may be moved using gravity so that the curable electrolyte composition 155 surrounds the electrode tab 121 .

In an embodiment, the curing step may include curing the curable electrolyte composition 155 disposed in the accommodating space 110p1 to a gel form so as to surround the electrode tab 121 . For example, as shown in FIG. 9 , when the curable electrolyte composition 155 includes a thermosetting compound, the curable electrolyte composition 155 may be thermally cured by storing the curable electrolyte composition 155 in a thermostat set at a predetermined temperature for a predetermined period of time or longer. there is. The temperature of the thermally curable compound is raised to form cross-links through a thermal polymerization reaction, so that the curable electrolyte composition 155 in a liquid state may be converted into a gel state. For example, when storing the pouch 114 inside a thermostat, the pouch 114 is placed inside a thermostat at 60 degrees Celsius for 5 to 24 hours to convert the curable electrolyte composition 155 into a gel state. can be stored.

10 is a front view showing the inside of the pouch 114 in which the curable electrolyte composition 155 accommodated in the accommodation space is UV-cured in the manufacturing method of the battery cell 100 according to another embodiment of the present invention. For reference, in FIG. 10, the pouch is shown transparently so that the inside of the pouch 114 can be seen from the outside for the purpose of drawing description.

Referring to FIG. 10 , in the method for manufacturing a battery cell 100 according to another embodiment of the present invention, the curable electrolyte composition 155 may include an ultraviolet curable compound (not shown). In this case, the curable electrolyte composition 155 injected into the receiving space 110p1 may be cured by ultraviolet rays. At this time, an ultraviolet curing device (not shown) may be used for irradiating ultraviolet (U) to photo-cure the ultraviolet curable compound.

In the case of using an ultraviolet curable compound, compared to the case of using a heat curable compound, a separate storage place such as a thermostat for thermal curing is unnecessary, thereby simplifying the electrode manufacturing process, and during the curing process, the electrode assembly 120 is not removed. The degree of temperature increase is small, and the negative effect on the performance of the battery cell 100 can be reduced.

In the manufacturing method according to another embodiment, the curable electrolyte composition may include a curable compound capable of being crosslinked when exposed to radiation. For example, the curable compound may include polyacrylic acid. The curable electrolyte composition may be gelled by exposure to radiation. For example, the curable electrolyte composition may be crosslinked with polyacrylic acid by irradiating gamma rays generated from an electron beam (E-BEAM), and may be changed into the gel electrolyte after crosslinking to a predetermined degree of crosslinking.

Therefore, according to this configuration of the present invention, the curable electrolyte composition uses a radiation crosslinking (curing) method, which is environmentally friendly as it does not require a harmful catalyst, unlike other general polymerization initiators, and at the same time, in a solid state or at low temperatures. can cause a chemical reaction. In addition, since the hardening treatment is possible in a short time, energy consumption is also small.

Referring back to FIGS. 7 to 9 , in the manufacturing method according to an embodiment of the present invention, the step of forming the blocking portion 113 may be performed before or after the injection of the curable electrolyte composition 155, preferably before. can The blocking part 113 may be configured to block the movement of the curable electrolyte composition 155 from the accommodation space 110p1 to the injection space 110p2. As shown in FIG. 9, when the pouch 114 is rotated at an angle of 90 degrees in a counterclockwise direction, that is, when the pouch 114 is rotated and disposed so that the electrode tab 121 faces downward, the curable electrolyte The composition 155 moves and is located on the first side 120a of the electrode assembly 120 in the accommodation space 110p1. The blocking part 113 may prevent the curable electrolyte composition 155 from moving from the accommodation space 110p1 to the injection space 110p2. More specifically, the blocking portion 113 may be formed between the injection space 110p2 and the accommodation space 110p1. The blocking part 113 may be formed to block a space between the injection space 110p2 and the accommodation space 110p1 of the pouch 114 . For example, as shown in FIG. 8 , the blocking portion 113 extends from the first outer circumferential portion 114a of the pouch 114 facing the electrode tab 121 to the third outer circumferential portion 114c. It may have an elongated shape.

Therefore, according to this configuration of the present invention, the manufacturing method of the present invention further includes the step of forming the blocking portion 113 before or after the injection of the curable electrolyte composition 155, so that the accommodation space 110p1 It is possible to prevent the injected curable electrolyte composition 155 from moving from the accommodation space 110p1 to the injection space 110p2 before curing. Accordingly, the manufacturing method of the present invention can prevent the curable electrolyte composition 155 from escaping into the injection space 110p2 in the curing step, and the curable electrolyte composition 155 is prevented by the blocking part 113. It is easy to maintain a state in which the curable electrolyte composition 155 is arranged to cover the electrode tab 121 until the curing step of the process, and manufacturing processability can be greatly improved.

In addition, in the step of forming the blocking portion 113, the blocking portion 113 may be formed to extend along the boundary between the accommodation space 110p1 and the injection space 110p2 from the outer periphery of the pouch 114. can For example, as shown in FIG. 8 , a blocking portion 113 extending from the first outer circumferential portion 114a along the boundary between the accommodation space 110p1 and the injection space 110p2 is formed in the pouch 114. can make it The blocking portion 113 may be formed to protrude more toward the third outer circumferential portion 114c of the electrode assemblies 120 than the ends of the first sides 120a of the electrode assemblies 120 .

11 is a front view showing the inside of the pouch 114 accommodating the cured gel electrolyte 150 in the accommodation space 110p1 in the manufacturing method of the battery cell 100 according to another embodiment of the present invention. . For reference, in FIG. 11, the pouch 114 is shown transparently so that the inside of the pouch 114 can be seen from the outside for drawing description.

Referring to FIG. 11 together with FIG. 2, in the method of manufacturing a battery cell 100 according to an embodiment, a portion of the electrode assembly 120 is in the gel electrolyte 150 in which the curable electrolyte composition 155 is cured. may be impregnated. For example, as shown in FIG. 11 , the depth D of one side of the electrode assembly 120 in which the electrode tab 121 impregnated with the gel electrolyte is formed may be 10 mm or less. When the immersion depth (D) of the electrode assembly 120 impregnated into the gel electrolyte 150 exceeds 10 mm, the gel electrolyte 150 has higher ion conduction resistance than the liquid electrolyte 160, and thus the electrode assembly 120 has a higher ion conduction resistance. (122) or may be a factor impairing the performance of the electrode assembly 120.

Therefore, according to this configuration of the present invention, in the manufacturing method of the present invention, the step of forming the blocking portion 113 is the blocking portion 113 of the electrode assembly 120 where the electrode tab 121 is located. A step of forming the electrode assembly 120 so as to protrude further into the electrode assembly 120 than one side end. The curable electrolyte composition 155 is in contact with the first side 120a of the electrode assembly 120 or is in the receiving space 110p1 to the extent of impregnating a part of the first side 120a as shown in FIG. can be sufficiently filled. Accordingly, in the present invention, the curable electrolyte composition 155 accommodated in the pouch 114 in which the blocking portion 113 is formed can be cured to form the gel electrolyte 150, where the electrode tab 121 is located. One side end of the electrode assembly 120 may be supported and fixed by the gel electrolyte 150 so as not to move toward the first outer circumferential portion 114a of the pouch 114 . Ultimately, the battery cell 100 manufactured by the manufacturing method of the present invention can effectively reduce damage to the electrode assembly 120 accommodated in the accommodation space 110p1 due to external impact.

Meanwhile, referring again to FIGS. 2, 7, and 8, in the step of forming the blocking portion 113, a portion between the injection space 110p2 and the accommodation space 110p1 of the pouch 114 is melt-bonded. steps may be included. That is, the blocking portion 113 may be formed to block a portion of the space by joining a portion of a region between the injection space 110p2 and the accommodation space 110p1 of the pouch 114 . For example, in the step of forming the blocking portion 113, the inner surfaces of the first cell sheet 114T and the second cell sheet 114P of the pouch 114 are in close contact with each other by hot pressing. can be thermally welded.

According to this configuration of the present invention, the manufacturing method of the present invention includes the step of melting and bonding a part between the injection space 110p2 of the pouch 114 and the accommodation space 110p1, thereby forming the injection space 110p2. Without a separate blocking member for blocking, the blocking portion 113 can be formed using the existing sealing device used to form the sealing portion 111 of the pouch 114, the blocking portion There is an advantage of minimizing the cost for forming (113).

12 is a side view showing a state before fixing a battery cell using a fixing jig 210 while the curable electrolyte composition 155 is cured in a method for manufacturing a battery cell according to another embodiment of the present invention. 13 is a side view showing a state in which the battery cell 100 is fixed using a fixing jig 210 while the curable electrolyte composition 155 is cured in a method for manufacturing a battery cell according to another embodiment of the present invention. . For convenience of description, electrode tabs and the like are not shown in FIGS. 12 and 13 .

Referring again to FIGS. 12 and 13 together with FIGS. 4 and 9, when the curable electrolyte composition 155 is injected into the pouch 114, due to the fluidity of the curable electrolyte composition 155, the curable electrolyte composition ( 155) may be convexly deformed in the outer direction. When the curable electrolyte composition 155 is cured in such a way that a portion of the receiving space 110p1 of the pouch 114 is convexly deformed, the deformity may be different for each product, so it is important to ensure consistent quality of the product. It may be difficult, and the appearance of the pouch 114 may not be smooth, resulting in defects. Accordingly, the curing step of the manufacturing method of the present invention may include pressing and fixing the pouch 114 while the curable electrolyte composition 155 is curing. At this time, both outer sides of the pouch 114 may be pressed and fixed using a fixing jig 210 . Specifically, the fixing jig 210 may include a first jig plate 212 and a second jig plate 213 . Each of the first jig plate 212 and the second jig plate 213 may have a size corresponding to or larger than one side of the pouch 114 . That is, each of the first jig plate 212 and the second jig plate 213 may have a size capable of covering the pouch 114 . The pouch 114 and the electrode assembly 120 accommodated inside the pouch 114 may be interposed between the first jig plate 212 and the second jig plate 213 . In addition, a portion of the convexly deformed accommodation space 110p1 of the pouch 114 may be pressed by the first jig plate 212 and the second jig plate 213 .

In addition, the fixing jig 210 may further include a pedestal 211 , a first support 214 , and a second support 215 . The first support 214 and the second support 215 may be located on both sides (Y-axis direction) with the pouch 114 as the center. The pedestal 211 may be configured to be mounted on the ground so that the fixing jig 210 can be stably positioned on the ground. The pedestal 211 may have a plate shape extending parallel to the ground. For example, as shown in FIG. 12, the first support 214 includes a pillar part 214a extending from the upper surface of the pedestal 211 in an upward direction (Z-axis direction), and horizontally from the pillar part 214a. A connection portion 214b extending in the direction and connected to a side portion of the first jig plate 212 in the positive direction of the Y axis may be provided. In addition, the second support 215 includes a pillar part 215a extending upward from the upper surface of the pedestal 211, and extending in a horizontal direction from the pillar part 215a and extending from the second jig plate 213. A connection portion 215b connected to a side in a negative direction of the Y axis may be provided.

Furthermore, the first support 214 and the second support 215 may be configured to be movable on the pedestal 211 in a direction closer to each other, or configured to be movable in a direction away from each other. For example, when the first support 214 and the second support 215 move in a direction closer to each other, the first jig connected to the first support 214 and the second support 215, respectively. The plate 212 and the second jig plate 213 may be moved closer to each other. At this time, both outer sides of the pouch 114 located between the first jig plate 212 and the second jig plate 213 are pressed to form the pouch 114 and the electrode assembly housed in the pouch 114. (120) can be fixed. For example, when curing of the curable electrolyte composition 155 is completed, the fixed state of the pouch 114 is released by moving the first support 214 and the second support 215 in a direction away from each other. can For example, as shown in FIG. 12 , the pouch 114 may have a shape in which a portion of the accommodation space 110p1 of the pouch 114 protrudes convexly due to the curable electrolyte composition 155 . However, as shown in FIG. 13, when the first support 214 and the second support 215 are moved toward the pouch 114, the first jig plate 212 and the second jig plate ( 213), the pouch 114 is pressurized, and this pressurization can guide the accommodation space 110p1 convex by the curable electrolyte composition 155 to be deformed into an enclosed form.

Therefore, according to this configuration of the present invention, the curing step includes a step of pressurizing and fixing the pouch 114 while the curable electrolyte composition 155 is curing, so that the electrode assembly accommodated inside the pouch 114 120 can be stably fixed, and a portion of the accommodation space 110p1 of the pouch 114 is convexly deformed due to the curable electrolyte composition 155, and the curable electrolyte composition 155 is Gelation can be prevented. Accordingly, the present invention can effectively reduce the defective rate of the battery cell 100 .

14 is a view of a blocking member 180 that presses a portion between the receiving space 110p1 and the injection space 110p2 of the pouch 114 in the manufacturing method of the battery cell 100 according to another embodiment of the present invention. It is a perspective view that represents the appearance. 15 is a portion between the receiving space 110p1 and the injection space 110p2 of the pouch 114 using the blocking member 180 in the manufacturing method of the battery cell 100 according to another embodiment of the present invention. It is a perspective view showing the pressurized state. For reference, in FIGS. 14 and 15, for convenience of explanation of the drawings, the inside of the pouch 114 is shown transparently so that it can be seen from the outside.

Referring again to FIGS. 14 and 15 together with FIG. 4 , forming the blocking portion 113 of the method for manufacturing a battery cell 100 according to another embodiment of the present invention is the pouch 114 A step of pressurizing and blocking a portion between the accommodation space 110p1 and the injection space 110p2 may be included. At this time, the manufacturing method of the present invention may pressurize a portion between the receiving space 110p1 and the injection space 110p2 by using a separate blocking member. The blocking member may temporarily form a blocking portion 113 in the pouch 114 so that the curable electrolyte composition 155 does not move from the accommodation space 110p1 to the injection space 110p2. For example, as shown in FIG. 15, a portion of the pouch 114 between the accommodation space 110p1 and the injection space 110p2 is pressed using a tongs member as the blocking member 180, thereby blocking the blocking portion 113. can be temporarily formed.

On the other hand, as the blocking member 180 for forming the blocking portion 113, a tong member in the form of a pin shown in FIG. 14 may be used. For example, as shown in FIG. 15 between the two fingers 181 of the tongs, after interposing a part between the receiving space 110p1 and the injection space 110p2 of the pouch 114, 2 The blocking portion 113 may be formed by closing the dog's fingers 181 and pressurizing a portion between the receiving space 110p1 and the injection space 110p2 .

Therefore, according to this configuration of the present invention, in the manufacturing method of the present invention, the step of forming the blocking portion 113 forms a portion between the receiving space 110p1 and the injection space 110p2 of the pouch 114. By including the step of pressing and blocking, the blocking portion 113 can be easily formed without heat-sealing a portion of the pouch 114, thereby effectively increasing manufacturing efficiency.

Meanwhile, referring again to FIGS. 8 and 9 together with FIG. 2, in the manufacturing method according to another embodiment of the present invention, the electrode tab 121 performed after the injection of the curable electrolyte composition 155 is the electrode ( The method may further include rotating the pouch 114 so as to be positioned below the 122s. In this case, the pouch 114 may be disposed such that the relatively wide surfaces of the cell sheets 114T and 114P are placed in the front-back direction (Y-axis direction). That is, the pouch 114 may be arranged to stand vertically with respect to the ground. For example, as shown in FIG. 9, the pouch 114 rotates clockwise or clockwise based on a view from the front (viewed in the Y-axis direction) of the pouch 114 after the injection of the curable electrolyte composition 155. By rotating at an angle of 90 degrees in a counterclockwise direction, the electrode tab 121 may be positioned below the electrode assembly 120 . That is, the pouch 114 may be rotated so that the electrode tab 121 is positioned toward the direction of gravity after the injection of the curable electrolyte composition 155 . At this time, the injected curable electrolyte composition 155 may be located in the lower part of the accommodation space 110p1 where the electrode tab 121 is located by gravity.

8, in the step of injecting the curable electrolyte composition 155, the injected curable electrolyte composition 155 is dispersed in the receiving space 110p1 of the pouch 114, and then the pouch 114 In the rotating arrangement step, the pouch 114 is rotated so that the electrode tab 121 is located at the bottom, so that the curable electrolyte composition 155 can cover the electrode tab 121 in the accommodation space 110p1. can be gathered at the bottom of

Therefore, according to this configuration of the present invention, the manufacturing method of the present invention is such that the electrode tab 121 performed after the injection of the curable electrolyte composition 155 is located under the electrode assembly 120 so that the pouch 114 ) By further including the step of disposing, the curable electrolyte composition 155 can be well collected in the lower part of the accommodation space 110p1 of the pouch 114 so as to cover the electrode tab 121, and the gel It is possible to effectively reduce the manufacturing defect rate of the battery cell 100 by preventing the electrolyte 150 from being disposed at a location other than the intended location. That is, since the amount of the curable electrolyte composition 155 collected on the first side 120a of the electrode assembly 120 is reduced, the effect of improving durability of the electrode tab 121 may deteriorate.

Moreover, when a portion of the gel electrolyte 150 remains between the electrodes 122, the gel electrolyte 150 has higher ion conduction resistance than the liquid electrolyte 160, so that only the liquid electrolyte 160 can be used. Compared to the battery cell, the performance of the battery cell may be relatively low. However, the manufacturing method of the present invention can minimize the remaining of the gel electrolyte 150 in the electrode assembly 120, thereby preventing the occurrence of defects in durability or poor performance of the manufactured battery cell.

16 is a perspective view showing the inside of the pouch 114 in which the liquid electrolyte 160 is injected into the accommodation space 110p1 in the battery cell manufacturing method according to another embodiment of the present invention.

Meanwhile, the composition of the liquid electrolyte may be the same as or different from that of the liquid electrolyte used in preparing the curable electrolyte composition.

Referring again to FIGS. 2, 4, 9, and 16, in the method of manufacturing a battery cell according to an embodiment of the present invention, the electrode tab 121 is the electrode assembly before the liquid electrolyte 160 injection step. Positioning in the X-axis direction of (120) may be further included. At this time, the pouch 114 may be erected in a vertical direction (Z-axis direction) with respect to the ground so that the accommodation space 110p1 can be seen from the front. At this time, since the curable electrolyte composition 155 has already undergone a phase change to form the gel electrolyte 150, the electrode tab 121 is located on the side (X-axis direction) of the electrode assembly 120. Even when the pouch 114 is rotated, the gel electrolyte 150 may not be moved to another location in the accommodation space 110p1. Also, the liquid electrolyte 160 may fill the remaining space of the accommodation space 110p1 where the gel electrolyte 150 is not located.

In detail, in the injection of the liquid electrolyte 160, the injection space 110p2 is injected through the open second outer peripheral portions 114b of the first and second cell sheets 114T and 114P. ) and injecting into the accommodation space 110p1. At this time, the liquid electrolyte 160 may be positioned between the electrodes 122 and surrounding the other side of the electrodes 1220 on which the electrode tabs 121 are not positioned. For example, the liquid electrolyte 160 may be located between the electrodes 122 and on the outermost side of the electrodes 122 . Also, as shown in FIG. 16 , the liquid electrolyte 160 may be positioned to surround the second side 120b, the third side 120c, and the fourth side 120d of the electrode assembly 120. .

Therefore, according to this configuration of the present invention, when the liquid electrolyte 160 located between the electrodes 122 is consumed during charging and discharging of the manufactured battery cell 100, the liquid electrolyte 160 located on the other side The liquid electrolyte 160 can be replenished by moving between the electrodes 122 by the amount of the consumed liquid electrolyte 160, so after a plurality of charge and discharge cycles of the battery cell 100, the liquid electrolyte 160 decreases. Even if it is possible to manufacture a battery cell 100 that can minimize the decrease in lifespan.

17 is a front view showing a state in which one side of the accommodation space 110p1 of the pouch 114 is additionally sealed in the manufacturing method of the battery cell 100 according to another embodiment of the present invention. And, FIG. 18 is a front view showing a state in which the injection space 110p2 of the pouch 114 is removed in the manufacturing method of the battery cell 100 according to another embodiment of the present invention.

Referring back to FIGS. 17 and 18 together with FIG. 4 , a method of manufacturing a battery cell 100 according to another embodiment of the present invention includes the steps of sealing the receiving space 110p1 of the pouch 114, and injection A step of cutting a region of the space 110p2 may be further included. Specifically, in the step of sealing the accommodating space 110p1 of the pouch 114, both the boundary between the accommodating space 110p1 and the injection space 110p2 of the pouch 114 may be heat-sealed. For example, as shown in FIG. 17 , the first outer circumferential portion 114a to the third outer circumferential portion 114c of the pouch 114 along the boundary between the receiving space 110p1 and the injection space 110p2 of the pouch 114 ), the sealing portion 111 may be formed by thermal fusion. For example, as in the manufacturing method of the battery cell 100 of FIG. 8 described above, a portion between the injection space 110p2 and the accommodation space 110p1 of the pouch 114 is thermally fused to form the blocking portion 113. , in order to additionally form the sealing portion 111, heat sealing may be performed from the blocking portion 113 to the third outer circumferential portion 114c of the pouch 114.

In addition, a cutting line (L) may be set outside the sealing part 111 . Then, as shown in FIG. 18 , the area of the injection space 110p2 of the pouch 114 may be removed by cutting along the cutting line L.

Furthermore, in the manufacturing method according to another embodiment of the present invention, a battery activation process may be performed before the step of sealing the accommodating space 110p1 of the pouch 114 performed in FIG. 17 . Here, the battery activation process is a process of first performing a charge/discharge operation in the battery cell 100 . During the charge/discharge operation of the battery cell 100, a large amount of gas is generated. The generated gas may move from the accommodation space 110p1 to the injection space 110p2 and be discharged to the outside through the open second outer peripheral portion 114b of the pouch 114 . In this battery activation process, the magnitude of the charging current and the charge/discharge time may vary depending on the materials of the positive electrode 122p and the negative electrode 122n.

In addition, in the manufacturing method according to another embodiment of the present invention, a battery aging process may be performed after the step of sealing the accommodating space 110p1 of the pouch 114 . At this time, the temperature may be, for example, 45 to 70 degrees Celsius and the aging time may be 1 to 3 days.

Therefore, according to this configuration of the present invention, the manufacturing method of the battery cell 100 of the present invention is to inject the curable electrolyte composition 155 so as to be disposed in a form surrounding the electrode tab 121, and then harden it to form a gel electrolyte. By forming 150, compared to the case where the liquid electrolyte 160 of the prior art battery cell 100 surrounds the electrode tab 121, when an external impact is applied to the manufactured battery cell 100, the above It surrounds the electrode tab 121 and can prevent deformation of the electrode tab 121 by the gel electrolyte 150 . Accordingly, even if frequent shocks and vibrations generated during movement are transmitted to the battery cell 100, such as in a car, the flow of the electrode tab 121 can be minimized by the gel electrolyte 150. Accordingly, the present invention can prevent electric charge and discharge of the electrode 122 from being deactivated due to disconnection of the electrode tab 121 due to frequent movement of the electrode tab 121 .

That is, the battery cell 100 manufactured by the manufacturing method of the present invention forms the gel electrolyte 150 in the accommodation space 110p1 so as to surround the electrode tab 121, so that the electrode tab 121 It is possible to manufacture a battery cell 100 having an increased lifespan by reducing damage. In addition, the manufacturing method of the present invention can manufacture the battery cell 100 that can prevent the battery capacity from decreasing during use by preventing disconnection of the electrode tab 121 of the battery cell 100.

In addition, the liquid electrolyte 160 between the electrodes 122 is reduced after a plurality of charge and discharge cycles by maximally securing the liquid electrolyte 160 with fluidity in the space between the accommodation space 110p1 and the electrode assembly 120. Even if it is possible to manufacture a battery cell 100 that can minimize the reduction in lifespan.

Meanwhile, FIGS. 19 to 22 show a method of manufacturing a battery cell according to another embodiment of the present invention. Specifically, FIG. 19 is a front view illustrating a step of primarily injecting a curable electrolyte composition 155 in a method of manufacturing a battery cell in which electrode tabs are led out in opposite directions. 20 is a front view showing a step of primary curing a curable electrolyte composition in a method for manufacturing a battery cell according to another embodiment of the present invention. 21 is a front view showing a step of secondary injecting a curable electrolyte composition 155 in a method for manufacturing a battery cell according to another embodiment of the present invention. 22 is a front view showing a step of secondary curing the curable electrolyte composition 155 in a method for manufacturing a battery cell according to another embodiment of the present invention. For reference, in FIGS. 19 to 22 , for convenience of explanation of the drawings, the inside of the pouch 114 is shown transparently so as to be visible from the outside.

19 to 22, in the manufacturing method according to another embodiment of the present invention, unlike the battery cell 100 of FIG. 3 in which the electrode tab 121 is formed only on one side of the electrode 122 plates, The electrode tabs 121 of the manufactured battery cell may be formed to face each other on at least two or more sides of each of the electrode plates (not shown). For example, as shown in FIG. 19, in the method of manufacturing a battery cell according to another embodiment of the present invention, positive electrode tabs 121a and negative electrode tabs 121b are formed on opposite sides of each of the electrodes 122. are formed one by one. Accordingly, as shown in FIG. 19 , the positive electrode tab 121a and the negative electrode tab 121b may be positioned on both sides 120a and 121c of the electrode assembly 120, respectively. In addition, compared to the pouch 114 of FIG. 9 , an additional blocking portion 113a may be further formed in the pouch 114 of FIG. 19 .

In addition, in the manufacturing method according to another embodiment of the present invention, the curable electrolyte composition 155 is added to each space of the side of the electrode assembly 120 where the electrode tab 121 is located in the accommodation space 110p1. The injection step and the curing step may be repeatedly performed. For example, as shown in FIG. 19, when the electrode tabs 121 are formed on both sides of the electrodes 122, in the step of injecting the curable electrolyte composition 155, the electrodes are placed in the accommodation space 110p1. The step of firstly injecting the curable electrolyte composition 155 into the space of one side 120a of the electrode assembly 120 where the tab 121 is located may be performed. In the curing step, the curable electrolyte composition 155 filled in the accommodation space 110p1 of one side 120a of the electrode assembly 120 of the pouch 114 may be cured first. After the primary curing step, the curable electrolyte composition is placed in the accommodation space 110p1 of the other side 120c of the electrode assembly 120 where the electrode tab 121 is located. Secondary curable electrolyte composition 155 injection step of secondly injecting (155), and 2 curing the curable electrolyte composition 155 filled in the accommodation space 110p1 of the other side 120c of the electrode assembly 120 The secondary curing step may be performed sequentially.

For example, as shown in FIG. 19, in the battery cell manufactured by the manufacturing method according to another embodiment of the present invention, the electrode tabs 121a and 121b are on both sides 120a and 120c of the electrode assembly 120, respectively. can be located In this case, in the manufacturing method of the present invention, in the step of injecting the curable electrolyte composition 155, the first side ( 120a), the curable electrolyte composition 155 may be primarily injected into the space facing the space. After primary injection of the curable electrolyte composition 155, as shown in FIG. The pouch 114 may be rotated so as to be located at the bottom. At this time, the curable electrolyte composition 155 may be blocked from moving from the accommodation space 110p1 to the injection space 110p2 by the blocking part 113 . Then, the curable electrolyte composition 155 filled in the space facing the first side 120a of the electrode assembly 120 may be cured until it becomes a gel state (primary curing step). Then, as shown in FIG. 20, after the primary curing step, the electrode tab 121 located on the first side 120a is located on one side of the X-axis direction with respect to the electrode assembly 120, the pouch (114) can be rotated. Then, in the receiving space 110p1 of the pouch 114, the curable electrolyte composition 155 is secondarily injected into the space facing the third side 120c of the electrode assembly 120 where the positive electrode tab 121b is located. can do. Furthermore, as shown in FIG. 22 , the pouch 114 may be rotated so that the electrode tab 121 located on the third side 120c is positioned below the electrode assembly 120 . At this time, the curable electrolyte composition 155 may be blocked from moving from the accommodation space 110p1 to the injection space 110p2 by the additional blocking part 113a. In addition, by raising the temperature of the curable electrolyte composition 155 filled in the space located on the third side 120c of the electrodes 122, the secondary injected curable electrolyte composition 155 is secondary cured until it becomes a gel state. can make it The secondly injected curable electrolyte composition 155 may be transformed into a gel electrolyte 150 .

In the manufacturing method according to another embodiment of the present invention, the secondly injected curable electrolyte composition 155 is secondarily cured until it becomes a gel state to form a gel electrolyte 150, and then a liquid electrolyte 160 is injected. The steps of removing the injection space 110p2 of the pouch 114 and sealing the pouch 114 may be further performed.

Except for the steps described in FIGS. 19 to 22 described above, the remaining manufacturing steps may be performed similarly to the steps of the manufacturing method according to another embodiment of the present invention described in FIGS. 7 to 18 . Therefore, the remaining processes for manufacturing the battery cell of the manufacturing method according to another embodiment of the present invention will be omitted.

23 is a perspective view showing a battery module 1000 according to an embodiment of the present invention.

Referring to FIG. 23 together with FIG. 1 , the present invention may provide a battery module 1000 including at least one battery cell 100 . The battery module 1000 includes a module housing 1100 accommodating the battery cell (not shown in FIG. 23) therein, external output terminals 1200 provided at the front end of the module housing 1100, and the A control unit 1300 controlling charging and discharging of the battery cell 100 may be included. In addition, when two or more battery cells 100 are provided, the battery module 1000 may further include a bus bar (not shown) electrically connecting the two or more battery cells 100 . The bus bar may be electrically connected to the electrode lead 130 of each of the battery cells 100 . In the battery module 1000 of the present invention, essential components other than the battery cell 100 can be applied as well-known configurations, and thus descriptions of these configurations will be omitted.

Example

Example 1.

(Preparation of liquid electrolyte composition)

LiPF ₆ was dissolved in a non-aqueous organic solvent in which ethylene carbonate (EC):ethylmethyl carbonate (EMC) was mixed in a volume ratio of 30:70 to a concentration of 1.0 M, and then vinylene carbonate (VC) was added in 1 wt of the total weight of the solvent. %, to prepare a liquid electrolyte.

(Preparation of Curable Electrolyte Composition)

After dissolving LiPF ₆ to a concentration of 1.0M in a non-aqueous organic solvent in which ethylene carbonate (EC):ethylmethyl carbonate (DMC) was mixed in a volume ratio of 30:70, trimethylolpropane triacrylate was used as a curing compound. A curable electrolyte composition (E1 ) was prepared.

(manufacture of electrode assembly)

Cathode active material (Li(Ni _0.8 Co _0.1 Mn _0.1 )O ₂ ), conductive material (carbon black), and binder (polyvinylidene fluoride: PVDF) were mixed in a 94:3:3 weight ratio of N-methyl-2- It was added to pyrrolidone (NMP) to prepare a slurry of a positive electrode active material (solid content: 48% by weight). The positive electrode active material slurry was applied to a positive electrode current collector (Al thin film) having a thickness of 15 μm, dried, and then subjected to a roll press to prepare a positive electrode. An anode active material slurry (solid content: 70% by weight) was prepared by adding a negative electrode active material (carbon powder), a binder (PVDF), and a conductive material (carbon black) to NMP as a solvent in a weight ratio of 96:3:1. After applying and drying the negative active material slurry on a negative electrode current collector (Cu thin film) having a thickness of 10 μm, a roll press was performed to prepare a negative electrode. An electrode assembly was prepared by sequentially stacking the positive electrode, the separator consisting of three layers of polypropylene/polyethylene/polypropylene (PP/PE/PP), and the negative electrode.

(Secondary battery manufacturing)

The prepared electrode assembly is accommodated in a pouch, and the curable electrolyte composition (E1) prepared above is first injected into a partial accommodation space to cover the electrode tab, and then used inside a thermostat and stored at a high temperature at 60 ° C. for 5 hours , the curable electrolyte composition was gelled. Subsequently, a second injection of the liquid electrolyte prepared above was injected into the remaining accommodation space of the pouch to impregnate the electrode assembly, and then the pouch was sealed to prepare a battery cell.

Example 2.

(Preparation of Curable Electrolyte Composition)

After dissolving LiPF ₆ to a concentration of 1.0M in a non-aqueous organic solvent in which ethylene carbonate (EC):ethylmethyl carbonate (DMC) was mixed in a volume ratio of 30:70, trimethylolpropane triacrylate was used as a curing compound. A curable electrolyte composition (E2) was prepared by adding 33 wt%, adding 0.06 wt% of AIBN (2,2'-azobis (iso-butyronitrile)) as a polymerization initiator and 1 wt% of vinylene carbonate (VC) as other additives did

(Secondary battery manufacturing)

A battery cell was manufactured in the same manner as in Example 1, except that the curable electrolyte composition (E2) prepared above was injected when the first curable electrolyte composition was injected.

Example 3.

A curable electrolyte composition (E3) was prepared in the same manner as in Example 1, except that PVDF-HFP (polyvinylidene-co-hexafluoropropylene) was used as the curable compound instead of trimethylolpropane triacrylate. did

Then, a battery cell was manufactured in the same manner as in Example 1, except that the curable electrolyte composition (E3) prepared above was injected when the first curable electrolyte composition was injected.

Comparative Example 1. (curable compound not added)

(Preparation of liquid electrolyte composition)

LiPF ₆ was dissolved in a non-aqueous organic solvent in which ethylene carbonate (EC):ethylmethyl carbonate (EMC) was mixed in a volume ratio of 30:70 to a concentration of 1.0 M, and then vinylene carbonate (VC) was added in 1 wt of the total weight of the solvent. %, to prepare a liquid electrolyte.

(Secondary battery manufacturing)

A battery cell was manufactured in the same manner as in Example 1 except that the electrode assembly prepared in Example 1 was stored in a pouch and then only the prepared liquid electrolyte was injected into the entire accommodation space inside the pouch. Specifically, a battery containing an amount of liquid electrolyte in an accommodation space where an electrode tab is formed, instead of not injecting the curable electrolyte composition and not carrying out the step of storing the pouch at a high temperature to cure the curable electrolyte composition. cell was made.

Comparative Example 2. (Including gel electrolyte in the entire accommodation space)

A battery cell was manufactured in the same manner as in Example 1, except that the curable electrolyte composition was injected into the entire receiving space including the electrode tab and the electrode assembly when manufacturing the secondary battery. Specifically, the battery in the same manner as in Example 1 except that the curable electrolyte composition (E1) was injected into the entire inner space of the pouch including the electrode tab and the electrode assembly during the first injection, and the liquid electrolyte was not injected. cell was made.

Experimental example

Experimental Example 1. Physical stability and capacity retention rate evaluation

The battery cells prepared in Examples 1 to 3 and the battery cells prepared in Comparative Examples 1 and 2 were each subjected to CC-CV (constant current-constant voltage) conditions at 25 ° C. until reaching 4.2V at 0.33C C-rate. After charging, 1/20 C cut-off, and then discharging under CC conditions up to 2.5V at a 0.33C C-rate, 3 cycles were performed, and then the initial discharge capacity was measured.

Then, each of the battery cells prepared in Examples 1 to 3 and the battery cells prepared in Comparative Examples 1 and 2 was dropped from a height of 1 m to a concrete floor a total of three times. After a total of three free falls, the battery cell was disassembled, and the number of disconnected electrode tabs among the electrode tabs was confirmed and shown in Table 1 below.

In addition, the battery cells prepared in Examples 1 to 3 and the battery cells prepared in Comparative Examples 1 and 2 subjected to the free fall CC-CV (constant current) until reaching 4.2V at 0.33C C-rate at 25 ° C. -Constant voltage) conditions, 1/20 C cut-off, and then discharged under CC conditions up to 2.5V at 0.33C C-rate, and then the discharge capacity was measured after free fall. The capacity retention rate (%) was calculated using Equation 1 below, and the results are shown in Table 1 below.

[Equation 1]

Capacity retention rate (%) = (discharge capacity after free fall / initial discharge capacity) × 100

Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 total number of electrode taps 7 7 7 7 7 Number of disconnected electrode tabs after free fall 0 0 0 3 0 Capacity rate (%) 99.8 99.9 99.8 56.9 99.8

Looking at Table 1, in the case of the battery cells prepared in Examples 1 to 3 and Comparative Example 2 in which the gel electrolyte was formed around the electrode tab, the battery cell of Comparative Example 1 not containing the gel electrolyte In comparison, it can be seen that the physical stability of the tab region is improved, so that disconnection of the electrode tab does not occur even after the battery cell is free-falling.

On the other hand, as a result of cell capacity evaluation conducted after free fall, in the case of the battery cells prepared in Examples 1 to 3 and the battery cells prepared in Comparative Example 2 in which disconnection of the electrode tab did not occur, most of the existing capacity was expressed, In the case of the battery cell manufactured in Comparative Example 1 in which the disconnection of the electrode tab occurred, it can be confirmed that a significant decrease in capacity is caused.

Experimental Example 2. Internal resistance evaluation

For electrochemical evaluation (internal resistance), after charging the battery cells prepared in Examples 1 to 3 and the battery cells prepared in Comparative Examples 1 and 2 at 0.33 C C-rate CC degree to SOC 50%, respectively, The voltage drop caused by applying a current of 2.5 C for 10 seconds was measured, and the internal resistance was calculated using Equation 2 below. And, based on the internal resistance value of the battery cell of Comparative Example 1 (100%), the internal resistance increase rate (%) of the battery cell prepared in Examples 1 to 3 and the battery cell prepared in Comparative Example 2 is calculated, The results are shown in Table 2.

[Equation 2]

R = V/I,

where R is the resistance, V is the voltage (potential difference), and I is the current.

Experimental Example 3. Evaluation of high-temperature cycle characteristics

The battery cells prepared in Examples 1 to 3 and the battery cells prepared in Comparative Example 2 were charged under CC-CV (constant current-constant voltage) conditions up to 4.2V at a rate of 0.33 C at 25 ° C, respectively, and 1/20 C After cut-off, it was discharged under CC conditions up to 2.5V at 033 C rate. The initial charge and discharge (activation) process of 3 cycles was performed with the charge and discharge as one cycle.

Subsequently, each of the lithium secondary batteries initially charged and discharged at a high temperature (45° C.) was charged under CC-CV conditions up to 4.2V at a rate of 0.33 C, cut-off at 1/20 C, and then charged at 2.5V at a rate of 0.33 C. 100 cycles were carried out with discharging under CC conditions up to 1 cycle.

The capacity retention rate was calculated by substituting the capacity after the initial charge/reversal and the capacity after the 100th cycle into Equation 3 below, and the results are shown in Table 2 below.

[Equation 3]

Capacity retention rate (%) = (discharge capacity after 100th cycle / discharge capacity after initial charge/discharge) × 100

Example 1 Example 2 Example 3 Comparative Example 2 Internal resistance increase rate (based on the resistance value of Comparative Example 1, %) 100.4 102.3 101.1 123.7 Capacity retention rate (%) after 40 cycles at 45°C 97.3 93.3 96.8 85.0

Looking at Table 2, in the case of the battery cells prepared in Examples 1 to 3, as the gel electrolyte is present only in the electrode tab portion, the resistance is slightly increased compared to the battery cell of Comparative Example 1 having only the liquid electrolyte, It can be seen that the internal resistance is significantly reduced compared to the battery cell of Comparative Example 2 in which the gel electrolyte is formed in the entire accommodation space including the electrode tab and the electrode assembly, other than the electrode tab accommodation area.

In addition, looking at Table 2, in the case of the battery cells prepared in Examples 1 to 3, as the internal resistance decreased, it was found that the capacity retention rate (%) after high temperature cycle characteristics was significantly improved compared to the battery cell of Comparative Example 2. can

Referring to these results, when preparing a battery cell having a curable electrolyte composition in which an appropriate amount of the curable compound of the present invention is added and disposed in a form surrounding an electrode tab, the battery cell while securing the effect of improving the durability of the battery cell It can be confirmed that the deterioration of battery performance can be reduced.

As described above, although the embodiments have been described with limited drawings, those skilled in the art can apply various technical modifications and variations based on the above. For example, the described techniques may be performed in an order different from the method described, and/or components of the described system, structure, device, circuit, etc. may be combined or combined in a different form than the method described, or other components may be used. Or even if it is replaced or substituted by equivalents, appropriate results can be achieved.

Therefore, other implementations, other embodiments, and equivalents of the claims are within the scope of the following claims.

100: battery cell 1000: battery module
110: cell case 110p1, 110p2: accommodation space, injection space
113, 113a: blocking unit, additional blocking unit
114, 114T, 114P: pouch, first cell sheet, second cell sheet
114a, 114b, 114c, 114d: first outer periphery, second outer periphery, third outer periphery, fourth outer periphery
120, 122, 122p, 122n, 170: electrode assembly, electrode, anode, cathode, separator
120a, 120b, 120c, 120d: first side, second side, third side, fourth side
121, 121a, 121b: electrode tab, positive electrode tab, negative electrode tab
130, 130a, 130b: electrode lead, positive lead, negative lead
140: insulating film 111: sealing part
150: gel electrolyte 155: curable electrolyte composition
160: liquid electrolyte
210: fixed jig
211, 212, 213: pedestal, first jig plate, second jig plate
214, 214a, 214b: first support, pillar, connection
215, 215a, 215b: second support, pillar, connection
180: blocking member (claw member)
181: finger of tong member

Claims (15)

A cell case having an accommodation space;
an electrode assembly in which a plurality of electrode plates and separators are alternately stacked and accommodated in the accommodation space;
an electrode tab extending outward from the electrode plate and electrically connecting the electrode plate and an external terminal;
a gel electrolyte accommodated while surrounding the electrode tab in the accommodation space to prevent movement of the electrode tab; and
A battery cell comprising a; liquid electrolyte accommodated in the accommodation space so as to surround the other side of the electrode assembly on which the electrode tab is not formed. According to claim 1,
The gel electrolyte is accommodated only in the peripheral area of the electrode tab,
The battery cell wherein the liquid electrolyte is accommodated in the remaining space not filled with the gel electrolyte among the accommodation spaces. According to claim 1,
The gel electrolyte is a battery cell containing a cured polymer in an amount of 3wt% to 30wt%. According to claim 1,
The gel electrolyte is accommodated in the accommodation space to impregnate one side of each of the electrode plates to which the electrode tab is connected, and the depth of one side of the electrode assembly impregnated with the gel electrolyte is 10 mm or less. A battery module comprising at least one battery cell according to claim 1 . As a battery cell manufacturing method,
preparing an electrode assembly having a plurality of electrode plates having an electrode tab formed on at least one side thereof, and a separator interposed between the electrode plates;
disposing the electrode assembly in the receiving space of the pouch;
injecting the curable electrolyte composition into the receiving space of the pouch through the injection space of the pouch so as to surround the electrode tab;
preventing the electrode tab from flowing by changing the curable electrolyte composition into a gel electrolyte; and
The manufacturing method of the battery cell according to claim 1 comprising the step of injecting a liquid electrolyte into the accommodation space so as to surround the other side of the electrode assembly on which the electrode tab is not formed. According to claim 6,
The curable electrolyte composition is a method for producing a battery cell comprising a curable compound in an amount of 3wt% to 30wt%. According to claim 6,
The step of changing the curable electrolyte composition into a gel electrolyte in a gel phase is a method of manufacturing a battery cell comprising the step of thermally curing, ultraviolet curing, or radiation curing the curable electrolyte composition. According to claim 6,
Before the step of injecting the curable electrolyte composition,
The method of manufacturing a battery cell further comprising the step of forming a blocking portion configured to block the curable electrolyte composition from moving from the accommodation space to the injection space. According to claim 9,
The step of forming the blocking part is
The battery cell comprising the step of forming the blocking portion so as to extend from the outer circumference of the pouch along the boundary between the accommodation space and the injection space and protrude further into the electrode assembly than one side end of the electrode assembly where the electrode tab is located. Manufacturing method of. According to claim 9,
The step of forming the blocking part is
A method of manufacturing a battery cell comprising the step of forming a part between the injection space and the accommodation space of the pouch by melting bonding or pressurizing a part between the accommodation space and the injection space of the pouch. According to claim 6,
Before the step of preventing the flow of the electrode tab by changing the curable electrolyte composition into a gel electrolyte,
The method of manufacturing a battery cell further comprising the step of fixing the shape of the curable electrolyte composition by pressing and fixing the pouch and the electrode assembly using a jig plate from outside the pouch. According to claim 6,
The step of preventing the flow of the electrode tab by changing the curable electrolyte composition into a gel electrolyte is performed in a state in which the pouch and the electrode assembly are pressurized and fixed. According to claim 6,
Injecting the curable electrolyte composition
Disposing the pouch and the electrode assembly so that the electrode tab is located under the electrode assembly, and accommodating the curable electrolyte composition so as to surround the electrode tab using gravity. According to claim 6,
The method of manufacturing a battery cell further comprising the step of rotating the pouch so that the electrode tab is located on the side of the electrode assembly before the step of injecting the liquid electrolyte.

Images