All solid state battery

Abstract

Regarding an all-solid-state battery, one embodiment of the all-solid-state battery includes a positive electrode plate having an active material on a positive electrode current collector, a solid electrolyte layer disposed on one side of the positive electrode plate, and a negative electrode plate disposed on one side of the solid electrolyte layer, the positive electrode plate including an activated region of the active material and a non-activated region that is laser-treated on an outer edge of the activated region.

Description

[Technical field]

[0001] The present invention relates to an all-solid-state battery, and more particularly, to an all-solid-state battery having an electrode structure that prevents an internal short circuit for stable operation of the cell. [Background technology]

[0002] An all-solid-state battery includes a positive electrode plate, a solid electrolyte layer, and a negative electrode plate. The solid electrolyte layer is a medium that conducts lithium ions. In the case of a lithium deposition type all-solid-state battery, lithium ions that move from the positive electrode plate are deposited as metal on the negative electrode plate and accumulated, and lithium metal is deposited on the negative electrode plate during charging, regardless of the presence or absence of active material on the negative electrode plate.

[0003] In an all-solid-state battery with a deposition-type negative electrode plate, there is no housing, and lithium ions that migrate from the positive electrode plate during charging are deposited from the negative electrode plate, and lithium ions that have accumulated in the negative electrode plate during discharging dissociate from the negative electrode plate and migrate back to the positive electrode plate.

[0004] During charging, lithium is deposited on the negative electrode plate, causing the volume of the all-solid-state battery to expand, and in a free state where no pressure is applied to the all-solid-state battery, lithium deposition becomes non-uniform. As charging and discharging proceed, the non-uniform lithium deposition increases, causing the solid electrolyte layer to crack partially, which may cause an internal short circuit. To solve the non-uniform lithium deposition, pressure is applied to the outside of the all-solid-state battery.

[0005] Meanwhile, positive and negative plates are formed by punching continuously supplied plates into unit plates of the correct shape mainly using a physical blade. The positive and negative plates formed by punching can be damaged by burrs on the edges of the plates. In other words, the active material can fall off from the edges, causing a short circuit in the cell.

[0006] In addition, the edges of the positive plate are abnormally activated by high pressure during cell manufacturing, which can easily cause a short circuit in the cell. The edges of the positive plate have a higher current density than other parts. Therefore, since the edges are more likely to short circuit, it is necessary to manage the edges of the positive plate, which are vulnerable to pressure. Summary of the Invention [Problem to be solved by the invention]

[0007] One embodiment is to provide an all-solid-state battery that prevents short circuits caused by damage to the edge of the positive electrode plate. Another embodiment is to provide an all-solid-state battery that prevents short circuits at the edge of the positive electrode plate under high pressure conditions. [Means for solving the problem]

[0008] An all-solid-state battery according to an embodiment includes a positive electrode plate having an active material on a positive electrode current collector, a solid electrolyte layer disposed on one side of the positive electrode plate, and a negative electrode plate disposed on one side of the solid electrolyte layer, the positive electrode plate including an activated region of the active material and a non-activated region that is laser-treated on an outer edge of the activated region.

[0009] The positive electrode plate may be formed by laser cutting a positive electrode current collector, which is continuously coated with an active material, together with an active material layer.

[0010] The non-activated region can block the entry and exit of lithium ions.

[0011] The non-activated region can block the entry and exit of lithium ions due to deformation of the active material crystal structure in the positive electrode plate.

[0012] The non-activated region can block the entry and exit of lithium ions by denaturing the solid electrolyte in the solid electrolyte layer.

[0013] The non-activated region may be comprised of the active material that is melted and deformed from the positive electrode current collector.

[0014] The positive electrode plate may be formed by cutting the positive electrode current collector, on which the active material is pattern-coated, using a laser.

[0015] The non-activated region may be formed in a convex portion on the outer edge. The non-activated region can be formed to have a width of 0.1 to 1 mm. Effect of the Invention

[0016] In an all-solid-state battery according to an embodiment, a positive plate is cut with a laser and an active material is removed from an outer edge of the positive plate by laser processing, thereby providing a non-activated region of a set range, and therefore, it is possible to prevent short circuits due to damage to the edge of the positive plate and short circuits due to high pressure conditions. [Brief description of the drawings]

[0017] [Figure 1] FIG. 2 is a cross-sectional view of an all-solid-state battery in a charged state according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a plan view of the positive electrode plate applied to FIG. 1. [Diagram 3] 3 is a cross-sectional view taken along line III-III in FIG. 2. [Figure 4] 1 is a comparative example showing an energy dispersive X-ray spectroscopy (EDS) image of a cross section of a physically cut positive electrode plate. [Diagram 5] 1 is an example of a scanning electron microscope (SEM) image of a cross section of a positive electrode plate cut with a laser. [Figure 6] 1 is an example of an energy dispersive X-ray spectroscopy (EDS) image of a cross section of a positive electrode plate cut with a laser. [Figure 7]7 is a graph showing the results of EDS analysis of a first selected area of ​​the cross section of the laser-cut positive electrode plate of FIG. 6. [Figure 8] 7 is a graph showing the results of EDS analysis of a second selected area of ​​the cross section of the laser-cut positive electrode plate of FIG. 6. [Figure 9] 7 is a graph showing the results of EDS analysis of a third selected area of ​​the cross section of the laser-cut positive electrode plate of FIG. 6. [Figure 10] 7 is a graph showing the results of EDS analysis of a fourth selected area of ​​the cross section of the laser-cut positive electrode plate of FIG. 6. [Figure 11] 7 is a graph showing the results of EDS analysis of a fifth selected area of ​​the cross section of the positive electrode plate cut by the laser in FIG. 6. [Figure 12] This is an image of the cross section of a positive plate cut with a laser. [Figure 13] FIG. 13 is a Raman mapping image of the cross section of the laser-cut positive electrode plate of FIG. 12. [Figure 14] 1 is a graph showing the results of Raman spectroscopy of a cross section of a physically cut positive electrode plate as a comparative example. [Figure 15] 1 is a graph showing a Raman spectrum analysis result of a cross section of a positive electrode plate cut by a laser in accordance with an embodiment of the present invention. [Figure 16] FIG. 11 is a cross-sectional view showing another example of a positive electrode plate applied to an all-solid-state battery according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, with reference to the accompanying drawings, an embodiment of the present invention will be described in detail so that a person having ordinary skill in the art to which the present invention belongs can easily carry out the embodiment. However, the present invention can be embodied in various different forms and is not limited to the embodiments described herein. In order to clearly explain the present invention in the drawings, parts that are not related to the description are omitted, and the same reference numerals are used to refer to the same or similar components throughout the specification.

[0019] 1 is a cross-sectional view of an all-solid-state battery in a charged state according to an embodiment of the present invention. Referring to FIG. 1, the all-solid-state battery of the embodiment includes a positive electrode plate 11, a solid electrolyte layer 12 disposed on one side of the positive electrode plate 11, a negative electrode plate 13 disposed on one side of the solid electrolyte layer 12, and a buffer film 20 disposed on one side of the negative electrode plate 13.

[0020] A stacked structure of the positive electrode plate 11, the solid electrolyte layer 12, and the negative electrode plate 13 forms a unit cell. The unit cell may be formed as a mono-cell (not shown) that charges and discharges on one side of the positive electrode plate 11.

[0021] 1, the unit cell may be formed as a bi-cell that charges and discharges on both sides of the positive electrode plate 11. The positive electrode plate 11 may be formed by laser cutting a positive electrode current collector 111, which is continuously coated with a positive electrode active material, together with positive electrode active material layers 112 and 114.

[0022] Fig. 2 is a plan view of the positive electrode plate applied in Fig. 1, and Fig. 3 is a cross-sectional view taken along line III-III in Fig. 2. Meanwhile, referring to Figs. 1 to 3, positive electrode plate 11 includes active material layers 112 and 114 formed by applying a positive electrode active material to both sides of a positive electrode current collector 111 made of aluminum.

[0023] The positive electrode active material layers 112, 114 include an activated region 112 of the positive electrode active material and a non-activated region 114 of the positive electrode active material. The non-activated region 114 is a laser-treated portion on the outer edge of the activated region 112, and is formed by irradiating the positive electrode active material on the outer edge of the activated region 112 with a laser after forming an active material layer on the positive electrode active material.

[0024] That is, unlike the active region 112 which allows the inflow and outflow of lithium ions during charging and discharging, the non-active region 114 is formed in a range set to block the inflow and outflow of lithium ions.

[0025] In the non-activated region 114, a laser is irradiated onto the active material layer from the positive electrode plate 11, and the active material crystal structure is deformed to block the movement of lithium ions. In addition, when the focus of the laser is brought close to the positive electrode collector 111, the positive electrode collector 111 melts and deforms, and the components of the positive electrode collector 111 are included in the positive electrode active material, so that the movement of lithium ions can be controlled.

[0026] For example, the non-activated region 114 may be formed with a width of 0.1 to 1 mm. If the width is less than 0.1 mm, the non-activated region 114 may be insufficient to function as a non-activated region due to its too small area, and if the width is more than 1 mm, the non-activated region 114 may be too large, which may reduce the capacity of the battery.

[0027] The non-activated region can also block the inflow and outflow of lithium ions by denaturing the solid electrolyte in the solid electrolyte layer. In this case, the solid electrolyte can be denatured by irradiating the outer periphery of the solid electrolyte layer with a laser, and the solid electrolyte can be denatured by irradiating the outer periphery of the solid electrolyte layer with a laser while the solid electrolyte film is renation-bonded to the active material layer of the negative electrode plate.

[0028] Such a non-activated region 114 can prevent a short circuit caused by the edge of the positive electrode plate 11 even under high pressure conditions of an all-solid-state battery. Also, in order to prevent a short circuit caused by damage to the edge of the positive electrode plate 11, the positive electrode plate 11 is manufactured by laser cutting, which will be described below in comparison with physical cutting.

[0029] When the positive electrode plate 11 is manufactured by laser cutting, it is possible to minimize the generation of burrs on the edge of the positive electrode plate 11 and to minimize short circuits caused by damage to the edge of the positive electrode plate 11.

[0030] FIG. 4 is an energy dispersive X-ray spectroscopy (EDS) image of a cross section of a physically cut positive plate as a comparative example. Table 1 shows the EDS analysis results of the cross section of the positive plate of FIG. 4 that was physically cut using a blade. The unit is atomic %.

[0031] K indicates the K edge of an element. The K edge is due to the electron transition of the K shell of an atom. K is the band of energy that is emitted when an element is activated by energy applied to it in spectroscopy, and this specific signal is used to determine the type of element. Therefore, K indicates a specific position value for finding the quantitative value of an element in an energy dispersive spectrometer (EDS).

[0032] [Table 1]

[0033] FIG. 5 is an example of an image of a scanning electron microscope (SEM, electron microscopy) of a cross section of a laser-cut positive plate, and FIG. 6 is an example of an image of an energy dispersive X-ray spectroscopy (EDS) of a cross section of a laser-cut positive plate. Table 2 shows the EDS analysis results of the cross sections of the laser-cut positive plate 11 of FIG. 5 and FIG. 6. The unit is atomic %.

[0034] [Table 2]

[0035] 7 to 11 are graphs showing the results of EDS analysis of the first to fifth selected regions of the cross section of the positive electrode plate cut with a laser. The results of the EDS analysis are shown as a relative value of intensity (au) with respect to energy (eV).

[0036] 5 to 11, the positive electrode active material formed on the cross section of the laser-cut positive electrode plate 11 changes due to laser irradiation. That is, the laser-cut cross section may include the positive electrode active material that is deformed by melting the positive electrode current collector 111. That is, the positive electrode active material on the cut cross section may be formed including an aluminum composite of the positive electrode current collector 111.

[0037] Comparing Table 2 and FIG. 5 with Table 1 and FIG. 4, the laser cut cross section shows a melted and pressed shape (MPS) of the positive active material, which is not observed in the physically cut cross section.

[0038] The pressed shape (MPS) prevents damage to the edge of the laser-cut cross section of the positive electrode plate 11, that is, the positive electrode active material from falling off, and prevents an internal short circuit caused by the fallen positive electrode active material.

[0039] Referring to FIG. 6, in a fourth selected area 4 and a fifth selected area 5 of the laser-cut cross section of the positive electrode plate 11, the aluminum composite of the positive electrode current collector 111 appears high due to heat.

[0040] That is, in the positive electrode plate 11, the aluminum compound was found to be 10% or less in the first to third selected areas (Selected Area 1 to Selected Area 3) located far from the positive electrode current collector 111, while the aluminum compound was found to be 20% or more in the fourth selected area (Selected Area 4) and the fifth selected area (Selected Area 5) adjacent to the positive electrode current collector 111. That is, the aluminum compound was found to be 40.4% in the fourth selected area (Selected Area 4) and 42.7% in the fifth selected area (Selected Area 5) of the laser-cut cross section of the positive electrode plate 11.

[0041] Figure 12 is an image of a cross section of a positive electrode plate cut with a laser, and Figure 13 is a Raman mapping image of the cut cross section of the positive electrode plate cut with a laser in Figure 12. From Figures 12 and 13, the same melted and pressed shape (MPS) of the positive active material was observed on the laser cut cross section of the positive electrode plate 11.

[0042] The pressed shape (MPS) prevents damage to the edge of the laser-cut cross section of the positive electrode plate 11, i.e., the positive electrode active material from falling off, and prevents an internal short circuit caused by the fallen positive electrode active material.

[0043] Fig. 14 is a graph showing the results of Raman spectrum analysis of a cross section of a physically cut positive electrode plate as a comparative example, and Fig. 15 is a graph showing the results of Raman spectrum analysis of a cross section of a laser cut positive electrode plate as an example. The results of the Raman spectrum analysis are shown as a relative value (au) of intensity with respect to the Raman shift.

[0044] 12 to 15, FIG. 14 is a comparative example and is a graph showing the results of Raman spectrum analysis of a cross section of a physically cut positive electrode plate, and FIG. 15 is an example and is a graph showing the results of Raman spectrum analysis of a cross section of a laser cut positive electrode plate 11.

[0045] Raman spectrum analysis shows that, unlike the physically cut cross section (see Figure 14), the laser cut cross section (see Figure 15) has a new peak at a Raman shift of 1100 cm-1, which is related to the aluminum composite.

[0046] It can also be seen that after laser cutting, aluminum composite is generated in a large amount in the middle of the thickness direction (vertical direction in FIG. 12) of the positive active material. The aluminum composite observed in the positive active material prevents damage to the edge of the cross section of the positive plate 11, i.e., the positive active material from falling off, and can prevent a short circuit caused by the fallen positive active material.

[0047] Meanwhile, the non-activated region 114 provided on the edge of the positive electrode plate 11 can be formed in the positive electrode active material layer in the same structure as that formed on the cut section during laser cutting by irradiating the edge with a laser. This non-activated region 114 plays a role of non-activating the movement of lithium ions during charging and discharging of the all-solid-state battery.

[0048] 1 again, the lithium deposit layer 135 is not formed in a discharged state, but is formed in a charged state by lithium ions passing through the solid electrolyte 12 in the activated region 112 of the positive electrode plate 11 and depositing from one surface of the negative electrode current collector 131. During discharge, the lithium ions in the lithium deposit layer 135 dissociate and move through the solid electrolyte layer 12 to the activated region 112 of the positive electrode plate 11, and the lithium deposit layer 135 disappears.

[0049] During charging, lithium ions do not move to the negative electrode plate 13 in the non-activated region 114, and lithium ions dissociated from the lithium deposit layer 135 during discharging do not move to the non-activated region 114 of the positive electrode plate 11. That is, the non-activated region 114 does not affect charging and discharging. Therefore, the non-activated region 114 does not contribute to an internal short circuit in the all-solid-state battery.

[0050] 16 is a cross-sectional view showing another embodiment of a positive electrode plate applied to an all-solid-state battery according to an embodiment of the present invention. Referring to FIG 16, the positive electrode plate 21 may be formed by cutting a positive electrode current collector 211, which is pattern-coated with a positive electrode active material, using a laser.

[0051] In this case, the positive electrode active material layer has an activated region 212 formed in a pattern and its outer periphery, i.e., the edge of the pattern that is raised in a convex shape. In this case, the non-activated region 214 is formed by irradiating the raised outer edge with a laser, and can block the movement of lithium ions during charging and discharging.

[0052] Referring again to FIG. 1, the negative electrode plate 13 includes a negative electrode active material layer 132 formed by applying a negative electrode active material to a cross section of a negative electrode current collector 131 made of stainless steel (SUS) or nickel-coated copper (Ni-coated Cu).

[0053] For convenience, the negative electrode active material layer 132 is shown here, but there may be cases where the negative electrode active material layer 132 is not present. In this case, the deposited lithium deposit layer 135 acts as the negative electrode active material layer. Also, only a polymer layer such as a polyvinylidene fluoride layer may be formed on the cross section of the negative electrode current collector 131.

[0054] A solid electrolyte layer (SE) 12 is laminated on the negative electrode active material layer 132. This lamination can be performed by direct coating of a solid electrolyte slurry, by transferring a solid electrolyte film, or by lamination bonding of a self-supporting solid electrolyte film and the negative electrode active material layer.

[0055] The buffer film 20 is disposed on the rear surface of the negative electrode current collector 131 of the negative electrode plate 13 in the unit cell, and is configured to provide elastic force in response to the lithium deposition layer 135 formed by deposition and dissociation of lithium on the negative electrode active material layer 132 and the negative electrode current collector 131 during charging and discharging.

[0056] In addition, the positive electrode plate 11 has a non-coated portion 113 protruding from the outer periphery of one side, and the negative electrode plate 13 has a non-coated portion 133 protruding from the outer periphery of the other side. When the unit cells are stacked to form an all-solid-state battery module, the non-coated portions 113 of the positive electrode plates 11 are stacked and electrically connected to each other, and the non-coated portions 113 of the negative electrode plates 13 are stacked and electrically connected to each other.

[0057] Although the above describes a preferred embodiment of the present invention, the present invention is not limited thereto, and various modifications can be made within the scope of the claims, the description of the invention, and the accompanying drawings, and it is to be understood that these also fall within the scope of the present invention. [Explanation of symbols]

[0058] 11, 21 Positive plate 12 Solid electrolyte layer 13 Negative plate 20 Buffer film 111, 211 Positive electrode current collector 112, 212 activation region 114, 214 non-activated region 131 Negative electrode current collector 132 Negative electrode active material layer 135 Lithium Deposit Layer

Claims

1. a positive electrode plate having an active material on a positive electrode current collector; a solid electrolyte layer disposed on one side of the positive electrode plate; and a negative electrode plate disposed on one side of the solid electrolyte layer, The positive electrode plate is an activation region of the active material; and A non-activated area is laser-treated at the outer edge of the activated area. Including solid-state batteries.

2. The positive electrode plate is 2. The all-solid-state battery according to claim 1, which is formed by laser cutting a positive electrode current collector on which the active material is continuously coated together with an active material layer.

3. The all-solid-state battery according to claim 1 , wherein the non-activated region blocks the inflow and outflow of lithium ions.

4. The all-solid-state battery according to claim 1 , wherein the non-activated region blocks the inflow and outflow of lithium ions by deformation of the active material crystal structure in the positive electrode plate.

5. 2. The all-solid-state battery according to claim 1, wherein the non-activated region blocks the entry and exit of lithium ions by transformation of a solid electrolyte in the solid electrolyte layer.

6. The all-solid-state battery according to claim 1 , wherein the non-activated region is included in the active material that is deformed by melting the positive electrode current collector.

7. The all-solid-state battery according to claim 1 , wherein the positive electrode plate is formed by cutting a positive electrode current collector on which the active material is pattern-coated with a laser.

8. The solid-state battery according to claim 7 , wherein the non-activated region is formed in a convex portion on an outer edge.

9. The all-solid-state battery according to claim 1, wherein the non-activated region is formed to have a width of 0.1 to 1 mm.

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