All-solid battery module and manufacturing method therefor

Abstract

Provided are an all-solid battery module and a manufacturing method therefor. The manufacturing method for the all-solid battery module comprises: a first step for preparing an all-solid battery cell in which a positive electrode plate, a solid electrolyte layer, and a negative electrode plate are stacked; a second step for placing a first pressing plate and a second pressing plate on both sides of the all-solid battery cell; a third step for pressing the all-solid battery cell to a maximum pressure using the first pressing plate and the second pressing plate; and a fourth step for reducing the pressure on the all-solid state battery cell to a final pressure lower than the maximum pressure after the third step, and then performing charging and discharging while maintaining the final pressure.

Description

All-solid-state battery module and manufacturing method thereof

[0001] The present invention relates to an all-solid-state battery module and a method for manufacturing the same, and more particularly, to an all-solid-state battery module and a method for manufacturing the same, wherein cell performance is improved through a pressurization process.

[0002] All-solid-state batteries comprise a cathode, a solid electrolyte, and an anode. The solid electrolyte layer acts as a medium for conducting lithium ions. In lithium deposition-type all-solid-state batteries, lithium ions migrate from the cathode and deposit metal on the anode. Regardless of the presence or absence of a cathode composite layer, lithium metal is deposited on the anode during charging.

[0003] In an all-solid-state battery with a precipitated negative electrode, lithium ions that migrate from the positive electrode are precipitated on the negative electrode during charging, and lithium ions that accumulate on the negative electrode are dissociated from the negative electrode and re-moved to the positive electrode during discharge. Thus, by employing a solid electrolyte layer, all-solid-state batteries can reduce the risk of fire and explosion compared to lithium secondary batteries that use liquid electrolytes, and can increase battery capacity.

[0004] However, due to the characteristics of the solid electrolyte layer, lithium ion conductivity is low, and resistance is high at each interface where the positive electrode plate, solid electrolyte layer, and negative electrode plate are in contact. Therefore, the pressure applied to the all-solid-state battery cell can induce uniform interfacial contact and cause forced deformation of lithium, which can affect the performance of the all-solid-state battery cell. In other words, the pressure applied to the all-solid-state battery cell can lower the interfacial resistance and improve the movement of lithium ions.

[0005] When manufacturing an all-solid-state battery cell, the stack pressure of the all-solid-state battery cell and the plate fastening pressure immediately before evaluating the all-solid-state battery cell for smooth lithium plating during charge and discharge also affect the performance of the all-solid-state battery cell.

[0006] One embodiment of the present invention provides a method for manufacturing an all-solid-state battery module that prevents internal short circuits by facilitating internal interface contact of an all-solid-state battery cell and improves cell life (capacity retention rate) and cell performance.

[0007] One embodiment of the present invention provides a method for manufacturing an all-solid-state battery module that improves the charge / discharge life of an all-solid-state battery cell.

[0008] One embodiment of the present invention provides an all-solid-state battery module manufactured by the above-described manufacturing method.

[0009] A method for manufacturing an all-solid-state battery module according to one embodiment of the present invention includes a first step of preparing an all-solid-state battery cell in which a positive electrode plate, a solid electrolyte layer, and a negative electrode plate are laminated, a second step of arranging a first pressure plate and a second pressure plate on both sides of the all-solid-state battery cell, a third step of pressurizing the all-solid-state battery cell to a maximum pressure through the first pressure plate and the second pressure plate, and a fourth step of performing charge and discharge while maintaining the pressure on the all-solid-state battery cell by reducing it to a final pressure lower than the maximum pressure after the third step.

[0010] The third step can gradually increase the pressure on the all-solid-state battery cell to reach the maximum pressure.

[0011] The third step may include a first pressurizing step of pressurizing to a first pressure higher than the final pressure, and a second pressurizing step of pressurizing to a maximum pressure higher than the first pressure.

[0012] The above final pressure may be 900 kgf, the above first pressure may be 1600 to 2000 kgf, and the above maximum pressure may be 2100 to 2500 kgf.

[0013] The third step may gradually increase the pressure on the all-solid-state battery cell until the maximum pressure is reached, and then gradually decrease the pressure.

[0014] The third step may include a first decompression step that gradually reduces the pressure to a second pressure higher than the final pressure, and a second decompression step that gradually reduces the pressure from the second pressure to the final pressure.

[0015] The above final pressure may be 900 kgf, the above maximum pressure may be 2200 kgf, and the above second pressure may be 1900 kgf.

[0016] An all-solid-state battery module according to one embodiment of the present invention includes an all-solid-state battery cell in which a positive electrode plate, a solid electrolyte layer, and a negative electrode plate are laminated, a first pressure plate and a second pressure plate arranged on both sides of the all-solid-state battery cell, and a first end plate and a second end plate arranged on each side of the first pressure plate and the second pressure plate to provide a pressure, wherein the first pressure plate and the second pressure plate pressurize the all-solid-state battery cell to a maximum pressure and then decompress and maintain the pressure on the all-solid-state battery cell to a final pressure lower than the maximum pressure.

[0017] The first pressure plate and the second pressure plate can maintain a minimum static friction coefficient of 0.3 between themselves and the outer material of the all-solid-state battery cell.

[0018] The first pressure plate and the second pressure plate may be formed with a Young's modulus of less than 80 GPa, which is the elastic modulus of the outer material of the all-solid-state battery cell.

[0019] The first pressure plate and the second pressure plate may include a flat portion that supports both sides of the all-solid-state battery cell, a long-side fixing portion that protrudes from both long sides of the flat portion and supports both long side surfaces of the all-solid-state battery cell, and a short-side fixing portion that protrudes from one short side of the flat portion and supports one short side.

[0020] The long side fixing portion and the short side fixing portion can protrude toward the first end plate and the second end plate to further support the side surfaces of the first end plate and the second end plate.

[0021] One embodiment of the present invention performs charging and discharging by pressurizing an all-solid-state battery cell to a maximum pressure using first and second pressurizing plates and then maintaining the pressure by reducing it to a final pressure lower than the maximum pressure, thereby facilitating interface contact within the all-solid-state battery cell. Accordingly, one embodiment can prevent internal short circuits, i.e., micro-shorts, in the all-solid-state battery cell, thereby improving cell life (capacity retention rate) and cell performance.

[0022] FIG. 1 is a cross-sectional view illustrating an all-solid-state battery module according to one embodiment of the present invention.

[0023] Figure 2 is a flowchart illustrating a method for manufacturing an all-solid-state battery according to a first embodiment of the present invention.

[0024] Figure 3 is a graph comparing the first to third embodiments and the first to fourth comparative examples of the present invention with the pressurization method of the prior art.

[0025] Figure 4 is a graph comparing the life characteristics according to the pressurizing method of the first to third embodiments and the first to fourth comparative examples of the present invention.

[0026] FIG. 5 is a cross-sectional view illustrating an all-solid-state battery module according to another embodiment of the present invention.

[0027] FIG. 6 is a plan view showing the bonding relationship between the all-solid-state battery cell, the first and second pressure plates, and the first and second end plates in FIG. 5.

[0028] Figure 7 is a plan view showing the bonding relationship between the all-solid-state battery cell and the first and second pressure plates.

[0029] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein. In the drawings, parts irrelevant to the description have been omitted to clearly explain the present invention, and the same reference numerals have been used throughout the specification to refer to identical or similar components.

[0030] FIG. 1 is a cross-sectional view illustrating an all-solid-state battery module according to one embodiment of the present invention. Referring to FIG. 1, an all-solid-state battery module (1) of one embodiment includes an all-solid-state battery cell (30), a first pressure plate (11), a second pressure plate (12), a first end plate (21), and a second end plate (22).

[0031] An all-solid-state battery cell (30) includes a positive electrode plate (31), a solid electrolyte layer (33), and a negative electrode plate (32) disposed on one side of the solid electrolyte layer (33). In the all-solid-state battery cell (30), a solid electrolyte layer (33) is disposed on one side of the positive electrode plate (31), and a negative electrode plate (32) is disposed on one side of the solid electrolyte layer (33).

[0032] The all-solid-state battery cell (30) is formed by a laminated structure of a positive electrode plate (31), a solid electrolyte layer (33), and a negative electrode plate (32), and although not shown, a plurality of unit cells using this as a unit cell may be formed by a laminated structure.

[0033] Although not specifically illustrated, the positive electrode plate (31) is formed by applying a positive electrode composite layer to a positive electrode current collector. The positive electrode plate (31) includes a positive electrode current collector made of aluminum and a positive electrode composite layer formed by applying slurry to both sides thereof. That is, during charging and discharging, the positive electrode composite layer allows lithium ions to enter and exit.

[0034] The negative electrode plate (32) includes a negative electrode current collector made of stainless steel or nickel-coated copper (Ni-coated Cu) and a negative electrode composite layer formed by applying slurry to one surface thereof. The negative electrode plate (32) may not have a negative electrode composite layer, in which case the deposited lithium deposition layer acts as the negative electrode composite layer.

[0035] The all-solid-state battery cell (30) further includes an outer shell (34). The outer shell (34) accommodates a unit cell or a plurality of stacked unit cells of a positive electrode plate (31), a solid electrolyte layer (33), and a negative electrode plate (32) formed in a laminated structure.

[0036] The first pressure plate (11) and the second pressure plate (12) are arranged on both sides of the all-solid-state battery cell (30). The first end plate (21) and the second end plate (22) are arranged on each side of the first pressure plate (11) and the second pressure plate (12) to provide a pressure force.

[0037] The first pressure plate (11) and the first end plate (21) provide a pressure force to the solid-state battery cell (30) on one side of the solid-state battery cell (30), and the second pressure plate (12) and the second end plate (22) provide a pressure force to the solid-state battery cell (30) on the other side of the solid-state battery cell (30).

[0038] The first pressure plate (11) and the second pressure plate (12) pressurize the all-solid-state battery cell (30) to the maximum pressure, and then reduce the pressure on the all-solid-state battery cell (30) to a final pressure (Pend) lower than the maximum pressure and maintain it.

[0039] The first pressure plate (11) and the second pressure plate (12) maintain a minimum coefficient of static friction between themselves and the outer material (34) of the all-solid-state battery cell (30). As an example, the minimum coefficient of static friction may be 0.3.

[0040] In addition, the first pressure plate (11) and the second pressure plate (12) may be formed to have a modulus of elasticity (Young's modulus) lower than that of the outer material (34) of the all-solid-state battery cell (30). For example, the modulus of elasticity (Young's modulus) of the outer material (34) may be 80 GPa. Accordingly, the modulus of elasticity of the first and second pressure plates (11, 12) is formed to be lower than 80 GPa.

[0041] An all-solid-state battery module (1) of one embodiment can be manufactured by the all-solid-state battery manufacturing method of the first to third embodiments (C1, C2, C3) described in FIGS. 2 to 4, and by applying a pressurization process, the effect of improving cell performance can be obtained.

[0042] FIG. 2 is a flowchart illustrating a method for manufacturing an all-solid-state battery according to a first embodiment of the present invention, and FIG. 3 is a graph comparing the first to third embodiments and the first to fourth comparative examples of the present invention with a pressurization method of the prior art.

[0043] Referring to FIGS. 2 and 3, the method for manufacturing an all-solid-state battery of the first embodiment includes a first step (ST1), a second step (ST2), a third step (ST3), and a fourth step (ST4). The first step (ST1) prepares an all-solid-state battery cell (30) as illustrated in FIG. 1.

[0044] The second step (ST2) places the first and second pressure plates (11, 12) on both sides of the all-solid-state battery cell (30). That is, the second step (ST2) places the first and second pressure plates (11, 12) on both sides of the outer surface of the outer material (34) of the all-solid-state battery cell (30).

[0045] Step 3 (ST3) pressurizes the all-solid-state battery cell (30) to the maximum pressure through the first and second pressure plates (11, 12). At this time, the first end plate (21) and the second end plate (22) provide a pressing force to each side of the first pressure plate (11) and the second pressure plate (12). Therefore, the pressing force provided to the first and second pressure plates (11, 12) through the first and second end plates (21, 22) pressurizes the all-solid-state battery cell (30).

[0046] Step 4 (ST4) performs charging and discharging while reducing or maintaining the pressure on the all-solid-state battery cell (10) to a final pressure (Pend) lower than the maximum pressure after Step 3 (ST3). At this time, the first end plate (21) and the second end plate (22) reduce the pressure from the maximum pressure on each side of the first pressure plate (11) and the second pressure plate (12). Therefore, the reduced pressure provided to the first and second pressure plates (11, 12) through the first and second end plates (21, 22) reduces and maintains the all-solid-state battery cell (30) to the final pressure (Pend). In this state, Step 4 (ST4) charges and discharges the all-solid-state battery cell (30).

[0047] Classification 1st pressure 2nd pressure Final pressure Remarks Conventional technology 500 800 900 Progressive pressurization 1st embodiment 1 600 2 100 Stabilization after pressurization above target pressure 2nd embodiment 2 000 2 500 3rd embodiment 2 200 1 900 Maximization of 1st pressure 1st Comparative example 800 1 200 Applying the pressure based on the conventional technology 2nd Comparative example 1 200 1 200 3rd Comparative example 1 500 900 4th Comparative example 2 500 3 500 Applying 1.5 times the pressure of the 1st embodiment

[0048] Referring to FIG. 3 and Table 1, the third stage (ST3) includes a first pressurization stage (ST31) and a second pressurization stage (ST32). The first pressurization stage (ST31) gradually pressurizes to a first pressure (P11, P12) higher than the final pressure (Pend). The second pressurization stage (ST32) gradually pressurizes from the first pressure (P11, P12) to a second pressure, which is a higher maximum pressure (Pmax1). As an example, the final pressure (Pend) may be 900 kgf, the first pressure (P11, P12) may be 1600 to 2000 kgf, and the second pressure, which is a maximum pressure (Pmax1, Pmax2), may be 2100 to 2500 kgf. In the first embodiment (S1), the first pressure (P11) is 2000 kgf, and the second pressure, which is the maximum pressure (Pmax1), is 2500 kgf. In the second embodiment (S2), the first pressure (P12) is 1600 kgf, and the second pressure, which is the maximum pressure (Pmax2), is 2100 kgf.

[0049] In comparison, in the prior art (C5), the first pressure is 500 kgf, and the maximum pressure is 800 kgf. The prior art (C5) gradually applies pressure from 0 to the first pressure, from the first pressure to the maximum pressure, and from the maximum pressure to the final pressure.

[0050] In the first and second comparative examples (C1, C2), the first pressure is 800 and 1200 kgf, and the second pressure, which is the maximum pressure, is 1200 and 1200 kgf. As in the prior art, the first and second comparative examples (C1, C2) are gradually pressurized from 0 to the first pressure, and from the first pressure to the second pressure, which is the maximum pressure, and are gradually depressurized from the maximum pressure to the final pressure (Pend).

[0051] Referring to FIG. 3 and Table 1, the third step (ST3) gradually increases the pressure on the all-solid-state battery cell (30) to reach the first pressure, which is the maximum pressure (Pmax3), and then gradually reduces it. The third step (ST3) includes a first depressurization step (ST33) and a second depressurization step (ST34). The first depressurization step (ST33) gradually reduces the pressure to a second pressure (P2) higher than the final pressure (Pend). The second depressurization step (ST34) gradually reduces the pressure from the second pressure (P2) to the final pressure (Pend).

[0052] As an example, the final pressure (Pend) is 900 kgf, the first pressure, which is the maximum pressure (Pmax3) in the third embodiment (S3), is 2200 kgf, and the second pressure (P2) is 1900 kgf.

[0053] In contrast, in the third comparative example (C3), the first pressure, which is the maximum pressure, is 1500 kgf, and the second pressure is 900 kgf. As in the prior art, the third comparative example (C3) gradually increases pressure from 0 to the maximum pressure, and then gradually reduces pressure from the maximum pressure to the second pressure, thereby maintaining the second pressure as the same as the final pressure.

[0054] In the fourth comparative example (C4), the first pressure is 2500 kgf, and the second pressure, which is the maximum pressure, is 3500 kgf. In the fourth comparative example (C4), 1.5 times the pressure of the first embodiment was applied. In the fourth comparative example (C4), the pressure is gradually increased from 0 to the first pressure, and from the first pressure to the second pressure, which is the maximum pressure, and the pressure is gradually reduced from the maximum pressure to the final pressure.

[0055] Figure 4 is a graph comparing the life characteristics according to the pressurization method of the first to third embodiments and the first to fourth comparative examples of the present invention. As in the first to third embodiments and the first to fourth comparative examples, various pressurization conditions were provided, and the life characteristics of each were examined.

[0056] Referring to Fig. 4 and Table 2, the capacity retention rate (%) at 200 cycles, which represents the life characteristics of the first to third embodiments, is 82.7 to 82.6%, and the capacity retention rate at 200 cycles, which represents the life characteristics of the first to third comparative examples, is 62.2 to 82.3%. In the fourth comparative example, an initial internal short occurred due to excessive pressurization, and the life evaluation could not be performed due to the internal short.

[0057] In Examples 1 to 3 and Comparative Examples 1 to 4, the initial capacities of the all-solid-state battery cells were at similar levels. However, it was found that the dispersion in the capacity retention rate of the all-solid-state battery cells of Examples 1 to 3 was smaller than that of Comparative Examples 1 to 4. Therefore, it can be seen that the life characteristics, i.e., the capacity retention rate, of Examples 1 to 3 are superior to those of Comparative Examples 1 to 4.

[0058] Classification Initial capacity (mAh / g) Lifetime characteristics (capacity retention rate) (%@200 cycles) First embodiment 2 35.06 8 2.7 Second embodiment 2 34.05 8 3.1 Third embodiment 2 35.49 8 2.6 First comparative example 2 32.05 7 2.1 Second comparative example 2 35.90 6 2.2 Third comparative example 2 29.80 8 2.3 Fourth comparative example 1 87.22 Lifetime evaluation is not possible due to initial short circuit

[0059] Hereinafter, an all-solid-state battery module (2) according to another embodiment of the present invention will be described. The all-solid-state battery module (2) according to another embodiment can be manufactured by the all-solid-state battery manufacturing method of the first to third embodiments disclosed in FIGS. 2 to 4, and can obtain the effect of improving cell performance by applying a pressurizing process. FIG. 5 is a cross-sectional view illustrating an all-solid-state battery module according to another embodiment of the present invention, FIG. 6 is a plan view illustrating a coupling relationship between an all-solid-state battery cell, first and second pressurizing plates, and first and second end plates in FIG. 5, and FIG. 7 is a plan view illustrating a coupling relationship between an all-solid-state battery cell and the first and second pressurizing plates.

[0060] Referring to FIGS. 5 to 7, the first pressure plate (41) and the second pressure plate (42) include a flat portion (431), a long-side fixing portion (432), and a short-side fixing portion (433). The flat portion (431) is arranged on both sides of the all-solid-state battery cell (30) to support both sides flatly.

[0061] The long-side fixing portion (432) protrudes from both long sides of the flat portion (431) and supports both long side surfaces of the all-solid-state battery cell (30). The short-side fixing portion (433) protrudes from one short side of the flat portion (431) and supports one short side.

[0062] The long-side fixing portion (432) and the short-side fixing portion (433) protrude toward the first end plate (51) and the second end plate (52) to further support the side surfaces (511, 521) of the first end plate (51) and the second end plate (52). The long-side fixing portion (432) and the short-side fixing portion (433) prevent slipping between the flat portion (431) and the solid-state battery cell (30) when pressing the solid-state battery cell (30) toward the flat portion (431).

[0063] Accordingly, in the all-solid-state battery module (1) of one embodiment, slippage between the flat portion (431) and the all-solid-state battery cell (30) can be sufficiently prevented without requiring the minimum required static friction coefficient between the first and second pressure plates (11, 12) and the all-solid-state battery cell (30), or even with a lower static friction coefficient.

[0064] Although the preferred embodiments of the present invention have been described above, 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 attached drawings, and it is obvious that this also falls within the scope of the present invention.

[0065] - Explanation of symbols -

[0066] 1, 2: All-solid-state battery module 11: First pressurized plate

[0067] 12: Second pressure plate 21: First end plate

[0068] 22: Second end plate 30: All-solid-state battery cell

[0069] 31: Bipolar plate 33: Solid electrolyte layer

[0070] 32: Negative electrode plate 34: Outer shell

[0071] 41: First pressure plate 42: Second pressure plate

[0072] 51: First and last plate 52: Second and last plate

[0073] P11, P12: First pressure P2: Second pressure

[0074] Pend: Final pressure Pmax1: Maximum pressure

[0075] Pmax2, Pmax3: Maximum pressure 431: Flat surface

[0076] 432: Long side fixing part 433: Short side fixing part

[0077] 511, 521: Side

Claims

1. The first step is to prepare an all-solid-state battery cell in which a positive electrode plate, a solid electrolyte layer, and a negative electrode plate are laminated; A second step of placing a first pressure plate and a second pressure plate on both sides of the above-mentioned all-solid-state battery cell; A third step of pressurizing the all-solid-state battery cell to the highest pressure through the first pressurizing plate and the second pressurizing plate; and After the above third step, a fourth step is performed to perform charging and discharging while maintaining the pressure on the all-solid-state battery cell at a final pressure lower than the maximum pressure. A method for manufacturing an all-solid-state battery module comprising:

2. In paragraph 1, The third step above is A method for manufacturing an all-solid-state battery module, wherein the pressure on the all-solid-state battery cell is gradually increased to reach the maximum pressure.

3. In paragraph 1, The third step above is A first pressurizing step for pressurizing to a first pressure higher than the final pressure, and A method for manufacturing an all-solid-state battery module, comprising a second pressurizing step of pressurizing from the first pressure to a higher maximum pressure.

4. In paragraph 3, A method for manufacturing an all-solid-state battery module, wherein the final pressure is 900 kgf, the first pressure is 1600 to 2000 kgf, and the maximum pressure is 2100 to 2500 kgf.

5. In paragraph 1, The third step above is A method for manufacturing an all-solid-state battery module, wherein the pressure on the all-solid-state battery cell is gradually increased until the maximum pressure is reached, and then gradually decreased.

6. In paragraph 1, The third step above is A first decompression step that gradually reduces the pressure to a second pressure higher than the final pressure, and A method for manufacturing an all-solid-state battery module, comprising a second depressurization step of gradually reducing the pressure from the second pressure to the final pressure.

7. In paragraph 6, A method for manufacturing an all-solid-state battery module, wherein the final pressure is 900 kgf, the maximum pressure is 2200 kgf, and the second pressure is 1900 kgf.

8. All-solid-state battery cell in which a positive electrode plate, a solid electrolyte layer, and a negative electrode plate are laminated; The first pressure plate and the second pressure plate arranged on both sides of the solid-state battery cell; and It includes a first end plate and a second end plate arranged on each side of the first pressure plate and the second pressure plate to provide a pressure force, The above first pressure plate and the above second pressure plate An all-solid-state battery module that pressurizes the above-mentioned all-solid-state battery cell to the maximum pressure, and then reduces the pressure on the above-mentioned all-solid-state battery cell to a final pressure lower than the maximum pressure and maintains it.

9. In paragraph 8, The above first pressure plate and the above second pressure plate An all-solid-state battery module that maintains a minimum coefficient of static friction of 0.3 between the outer material of the above-mentioned all-solid-state battery cell.

10. In paragraph 8, The above first pressure plate and the above second pressure plate An all-solid-state battery module formed with an outer material of the above-mentioned all-solid-state battery cell having an elastic modulus (young's modulus) of less than 80 GPa.

11. In paragraph 8, The above first pressure plate and the above second pressure plate A flat surface supporting both sides of the above solid-state battery cell, Long side fixing parts that protrude from both long sides of the above-mentioned flat portion and support both long side surfaces of the above-mentioned all-solid-state battery cell, and An all-solid-state battery module comprising a short-side fixing portion that protrudes from one side of a short side of the above-mentioned flat portion and supports one side of the short side.

12. In paragraph 8, The above long side fixing part and the above short side fixing part An all-solid-state battery module that protrudes toward the first and second end plates to further support the side surfaces of the first and second end plates.

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