Battery cell pressing pad and battery cell pressing apparatus comprising same

Abstract

The present invention relates to a battery cell pressing pad for pressing a battery cell including an electrode and a solid electrolyte stacked together, the battery cell pressing pad comprising: a first pressing pad which is brought into contact with one surface of the battery cell and presses the one surface of the battery cell; and a second pressing pad which is stacked on the first pressing pad and is brought into contact with one surface of a pressing jig. More specifically, the present invention relates to a battery cell pressing pad for improving the performance of an all-solid-state battery cell.

Description

Battery cell pressurizing pad and battery cell pressurizing device including the same

[0001] The present invention relates to a battery cell pressurizing pad and a battery cell pressurizing device including the same, and more particularly, to a battery cell pressurizing pad for improving the performance of an all-solid-state battery cell.

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0146536, filed October 30, 2023, and Korean Patent Application No. 10-2024-0134545, filed October 4, 2024, the entire contents of which are incorporated herein by reference.

[0003] As technological development and demand for mobile devices increase, rechargeable secondary batteries are being widely used as a power source for various mobile devices. Furthermore, secondary batteries are also attracting attention as an energy source for electric and hybrid vehicles, which are being proposed as a solution to address air pollution caused by existing gasoline and diesel vehicles.

[0004] Secondary batteries are classified into coin-type batteries, cylindrical batteries, square batteries, and pouch-type batteries depending on the shape of the battery case. Among these, pouch-type batteries are garnering much attention because their exterior is constructed using a pouch outer material composed of a multilayer film of a metal layer (foil) and synthetic resin layers coated on the upper and lower surfaces of the metal layer. This significantly reduces the weight of the battery compared to cylindrical or square batteries that use metal cans, enabling lightweight batteries and allowing for various changes in shape.

[0005] Pouch-type batteries are typically manufactured through a process of activating the battery cells after the battery assembly process. This activation process typically involves pressing the battery cells with a jig and applying current to the cells to charge and discharge them to a predetermined voltage.

[0006] In the manufacture of pouch-type batteries, it is important to apply uniform pressure during the cell assembly process. In particular, it is crucial to ensure a good contact interface between the positive and negative electrodes and the solid electrolyte during the all-solid-state battery manufacturing process.

[0007] However, in order to improve the contact between the positive and negative electrodes and the solid electrolyte, charging or discharging is performed while applying a clamping pressure to the battery cell. At this time, uneven pressure is applied to the battery cell area, which reduces the cell life performance and affects the initial charge / discharge efficiency, etc.

[0008] Therefore, it is necessary to develop a pressurized pad to ensure excellent initial charge / discharge efficiency and performance of all-solid-state batteries and to ensure smooth charge / discharge cycles.

[0009] [Previous literature]

[0010] (Patent Document 1) Japanese Patent No. 6912658 (July 12, 2021)

[0011] One of the objects of the present invention is to provide a battery cell pressurizing pad that allows uniform pressure to be applied when a battery cell is fastened to a jig in the manufacture of an all-solid-state battery.

[0012] Another object of the present invention is to provide a battery cell pressurizing pad that enables the manufacture of a battery having excellent initial charge / discharge efficiency and improved performance.

[0013] Another object of the present invention is to provide a battery cell pressurizing pad that improves the charge / discharge cycle performance of an all-solid-state battery.

[0014] As one embodiment of the present invention, a battery cell pressing pad for pressing a battery cell having an electrode and a solid electrolyte laminated therein is provided, the battery cell pressing pad including a first pressing pad that contacts one side of the battery cell and presses the one side of the battery cell, and a second pressing pad laminated on the first pressing pad and contacting one side of a pressing jig.

[0015] As one embodiment of the present invention, the first pressing pad presses both sides of the battery cell, and a battery cell pressing pad is provided including a first pressing pad pressing one side of the battery cell and a first pressing pad pressing the other side of the battery cell.

[0016] As one embodiment of the present invention, the second pressure pad includes a second-first pressure pad laminated on the first-first pressure pad and a second-second pressure pad laminated on the first-second pressure pad, and the second-first pressure pad and the second-second pressure pad provide battery cell pressure pads that each contact one side of a pressure jig facing each other.

[0017] As one embodiment of the present invention, a battery cell pressurizing pad is provided in which the CFD (Compression Force Deflection) 60% value of the first pressurizing pad and the second pressurizing pad is 4,000 kPa or more.

[0018] As one embodiment of the present invention, a battery cell pressurizing pad is provided in which a CFD 60% value of the first pressurizing pad is greater than a CFD 60% value of the second pressurizing pad.

[0019] As one embodiment of the present invention, a battery cell pressurizing pad is provided in which a CFD 60% value of the first pressurizing pad is 7,000 kPa or more.

[0020] As one embodiment of the present invention, a battery cell pressing pad is provided in which a ratio of the thickness (Tc) of the battery cell and the thickness (T1) of the first pressing pad is 1:0.01 to 0.5.

[0021] As one embodiment of the present invention, a battery cell pressure pad is provided in which the thickness of the first pressure pad satisfies the following equation 1:

[0022] [Formula 1]

[0023] T1> T p - T u

[0024] In the above equation 1,

[0025] T p is the thickness of the positive electrode within the battery cell,

[0026] T u is the thickness of the pouch film inside the battery cell.

[0027] As one embodiment of the present invention, a battery cell pressure pad is provided in which, when the first pressure pad is compressed multiple times at a strain of 80% based on the initial thickness, the thickness of the first pressure pad is reduced by 60% or more based on the initial thickness.

[0028] As one embodiment of the present invention, a battery cell pressurizing pad is provided in which the CFD 50% value of the first pressurizing pad and the second pressurizing pad is 2,000 kPa or more.

[0029] As one embodiment of the present invention, a battery cell pressurizing pad is provided in which a CFD 50% value of the first pressurizing pad is greater than a CFD 50% value of the second pressurizing pad.

[0030] As one embodiment of the present invention, a battery cell pressurizing pad is provided in which the value of 50% of the CFD (Compression Force Deflection) of the first pressurizing pad is 3,000 kPa or more.

[0031] As one embodiment of the present invention, a battery cell pressurizing device including the battery cell pressurizing pad is provided.

[0032] As one embodiment of the present invention, a battery cell pressurizing device is provided in which a battery cell is placed between the battery cell pressurizing pads.

[0033] As one embodiment of the present invention, a battery cell pressurizing device for uniaxially or isotropically pressurizing the battery cell is provided.

[0034] The battery cell pressurizing pad according to the present invention can ensure that uniform pressure is applied when fastening a battery cell to a jig.

[0035] The battery cell pressurizing pad according to the present invention can manufacture an all-solid-state battery with excellent initial charge / discharge efficiency and improved performance.

[0036] The battery cell pressurizing pad according to the present invention can improve the charge / discharge cycle performance of an all-solid-state battery.

[0037] FIG. 1 is a schematic diagram showing a battery cell pressurizing pad according to one embodiment of the present invention.

[0038] Figure 2 is a schematic diagram showing a battery cell pressurizing pad according to one embodiment of the present invention.

[0039] FIG. 3 is a diagram showing the charge / discharge rate of a battery cell pressed using a battery cell pressurizing pad according to Example 1, Comparative Examples 1 and 2 of the present invention.

[0040] FIG. 4 is a diagram showing the cycle maintenance rate of a battery cell pressed using a battery cell pressurizing pad according to Example 1, Comparative Examples 1 and 2 of the present invention.

[0041] FIG. 5 is a diagram showing the charge / discharge rate of a battery cell pressed using a battery cell pressurizing pad according to Example 1, Comparative Examples 3 and 4 of the present invention.

[0042] FIG. 6 is a diagram showing the cycle maintenance rate of a battery cell pressed using a battery cell pressurizing pad according to Example 1, Comparative Examples 3 and 4 of the present invention.

[0043] FIG. 7 is a diagram showing the charge / discharge rate of a battery cell pressed using a battery cell pressurizing pad according to Example 1 and Comparative Example 5 of the present invention.

[0044] FIG. 8 is a diagram showing the cycle maintenance rate of a battery cell pressed using a battery cell pressurizing pad according to Example 1 and Comparative Example 5 of the present invention.

[0045] Figure 9 is a drawing showing a compression curve of a pressurized pad according to Comparative Example 6 of the present invention.

[0046] FIG. 10 is a diagram showing the charge / discharge rate of a battery cell pressed using a battery cell pressurizing pad according to Example 2 and Comparative Example 6 of the present invention.

[0047] FIG. 11 is a diagram showing the cycle maintenance rate of a battery cell pressed using a battery cell pressurizing pad according to Example 2 and Comparative Example 6 of the present invention.

[0048] FIG. 12 is a diagram showing the charge / discharge rate of a battery cell pressed using a battery cell pressurizing pad according to Example 1 and Comparative Example 7 of the present invention.

[0049] FIG. 13 is a diagram showing the cycle maintenance rate of a battery cell pressed using a battery cell pressurizing pad according to Example 1 and Comparative Example 7 of the present invention.

[0050] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. For convenience of explanation, the drawings may show exaggerated representations of all or part of the components.

[0051] In addition, it will be apparent to those skilled in the art that the present invention is not limited to the attached drawings or the contents described in this specification, and that the present invention can be implemented in various forms without departing from the technical spirit of the present invention.

[0052] During the manufacturing process of all-solid-state batteries, interfacial contact between the electrodes and the solid electrolyte is crucial for improving battery performance, including initial charge-discharge efficiency, and for improving charge-discharge cycles. To achieve this interfacial contact, the battery cell must be pressurized at high pressure. In other words, during the pressurization process of all-solid-state battery manufacturing, uniform pressure must be applied to the battery cell to facilitate lithium ion movement.

[0053] However, in order to improve contact between the positive and negative electrodes and the solid electrolyte, charging or discharging is performed while applying a clamping pressure to the battery cell. However, if uneven pressure is applied to the battery cell area, this causes a problem in that the cell life performance deteriorates and the initial charge / discharge efficiency deteriorates.

[0054] To solve these problems, the inventors of the present invention have completed a battery cell pressurizing pad that can improve contact between an electrode and a solid electrolyte during a pressurizing process and apply uniform pressure to a battery cell.

[0055]

[0056] Before going into a specific description of a battery cell pressurizing pad according to one embodiment of the present invention, the configuration of a battery cell pressurized by the pressurizing pad will first be briefly described.

[0057] A battery cell according to the present invention may include a first electrode, an electrolyte layer, and a second electrode, which are sequentially stacked. Here, the first electrode may be a positive electrode or a negative electrode. The second electrode may be a negative electrode or a positive electrode. The first electrode and the second electrode may be different electrodes.

[0058] The electrolyte layer is disposed between the first electrode and the second electrode, and may have an area equal to or larger than the first electrode and the second electrode. Here, the electrolyte layer may be a solid electrolyte, but is not limited to these examples.

[0059] The above battery cell may include a pouch film on the outermost surface.

[0060] FIG. 1 is a schematic diagram showing a battery cell pressurizing pad according to one embodiment of the present invention.

[0061] Referring to FIG. 1, a battery cell pressurizing pad according to one embodiment of the present invention may include a first pressurizing pad (101) that presses a battery cell (10) in which an electrode and a solid electrolyte are laminated, contacts one side of the battery cell (10), and presses one side of the battery cell, and a second pressurizing pad (102) that is laminated on the first pressurizing pad and contacts one side of a pressurizing jig (20).

[0062] Figure 2 is a schematic diagram showing a battery cell pressurizing pad according to one embodiment of the present invention.

[0063] Referring to FIG. 2, in a battery cell pressurizing pad according to one embodiment of the present invention, a first pressurizing pad (101) presses both sides of a battery cell with a battery cell (10) interposed therebetween, and may include a 1-1 pressurizing pad (101-1) pressing one side of the battery cell and a 1-2 pressurizing pad (101-2) pressing the other side of the battery cell. The one side and the other side of the battery cell may be sides facing each other.

[0064] In addition, in the battery cell pressurizing pad according to one embodiment of the present invention, the second pressurizing pad includes a second-first pressurizing pad (102-1) laminated on the first-first pressurizing pad and a second-second pressurizing pad (102-2) laminated on the first-second pressurizing pad, and the second-first pressurizing pad (102-1) and the second-second pressurizing pad (102-2) can each contact one side of a pressurizing jig (20, 20') facing each other.

[0065] A battery cell pressurizing pad according to one embodiment of the present invention includes a first pressurizing pad and a second pressurizing pad, thereby enabling uniform pressure to be applied to the battery cell due to the pressurizing pads having different physical properties.

[0066] According to one embodiment of the present invention, the battery cell pressurizing pad may have a CFD (Compression Force Deflection) 60% value of the first pressurizing pad and the second pressurizing pad of 4,000 kPa or more. Here, CFD (Compression Force Deflection) means a compression force deflection, which is a measure of the force required to compress the pressurizing pad to a specific strain (e.g., 50%, 60%). The CFD value is a method of characterizing the firmness and softness of a material, and is used to measure the physical properties of the material. In addition, in terms of the relationship between stress and strain for a material, compression represents a type of force, and deflection represents an amount of movement based on a starting value (thickness).

[0067] Specifically, the CFD 60% values ​​of the first pressurized pad and the second pressurized pad are 4,000 kPa or more, 4,100 kPa or more, 4,200 kPa or more, 4,300 kPa or more, 4,400 kPa or more, 4,500 kPa or more, 4,600 kPa or more, 4,700 kPa or more, 4,800 kPa or more, 4,900 kPa or more, 5,000 kPa or more, 5,100 kPa or more, 5,200 kPa or more, 5,300 kPa or more, 5,400 kPa or more, 5,500 kPa or more, 5,600 kPa or more, 5,700 kPa or more, 5,800 kPa or more, 5,900 kPa or more, 6,000 kPa or more, 6,100 kPa or more, It can be 6,200 kPa or more, 6,300 kPa or more, 6,400 kPa or more, 6,500 kPa or more, 6,600 kPa or more, 6,700 kPa or more, 6,800 kPa or more, 6,900 kPa or more, or 7,000 kPa or more.

[0068] In a battery cell pressurizing pad according to one embodiment of the present invention, a value of CFD 60% of the first pressurizing pad may be greater than a value of CFD 60% of the second pressurizing pad.

[0069] According to one embodiment of the present invention, the battery cell pressurizing pad may have a CFD 60% value of the first pressurizing pad of 7,000 kPa or more.

[0070] In a battery cell pressurizing pad according to one embodiment of the present invention, a ratio of a thickness (Tc) of the battery cell and a thickness (T1) of the first pressurizing pad may be 1:0.01 to 0.5. The thickness of the first pressurizing pad may be 1% to 50% smaller than the thickness of the battery cell. Here, when the thickness of the first pressurizing pad is less than 1% or greater than 50% of the thickness of the battery cell, it may be difficult to apply a uniform pressure when pressing the battery cell.

[0071] In a battery cell pressurizing pad according to one embodiment of the present invention, the thickness (T1) of the first pressurizing pad can satisfy the following equation 1:

[0072] [Formula 1]

[0073] T1> T p - T u

[0074] In the above equation 1,

[0075] T p is the thickness of the positive electrode within the battery cell,

[0076] T u is the thickness of the pouch film inside the battery cell.

[0077] In the above equation 1, T p represents the thickest part within the battery cell, and T u may represent the thinnest part within a battery cell.

[0078] The thickness (T1) of the first pressure pad is T p - Tu If the value is less than or equal to the value, it may be difficult to apply uniform pressure when pressing the battery cell with the first pressurizing pad.

[0079] In a battery cell pressurizing pad according to one embodiment of the present invention, when the first pressurizing pad is compressed multiple times at a strain of 80% based on the initial thickness, the thickness of the first pressurizing pad can be reduced by 60% or more based on the initial thickness.

[0080] The stiffness of the first pressure pad can increase as it is compressed multiple times at a high strain rate based on the initial thickness. This indicates that the first pressure pad has excellent elastic restoring force.

[0081] In a battery cell pressurizing pad according to one embodiment of the present invention, the CFD 50% value of the first pressurizing pad and the second pressurizing pad may be 2,000 kPa or more.

[0082] Specifically, the CFD 50% values ​​of the first pressurized pad and the second pressurized pad may be 2,000 kPa or more, 2,100 kPa or more, 2,200 kPa or more, 2,300 kPa or more, 2,400 kPa or more, 2,500 kPa or more, 2,600 kPa or more, 2,700 kPa or more, 2,800 kPa or more, 2,900 kPa or more, 3,000 kPa or more, 3,100 kPa or more, 3,200 kPa or more, 3,300 kPa or more, 3,400 kPa or more, 3,500 kPa or more, 3,600 kPa or more, 3,700 kPa or more, 3,800 kPa or more, 3,900 kPa or more, and 4,000 kPa or more.

[0083] In a battery cell pressurizing pad according to one embodiment of the present invention, a CFD 50% value of the first pressurizing pad may be greater than a CFD 50% value of the second pressurizing pad.

[0084] According to one embodiment of the present invention, the battery cell pressurizing pad may have a CFD 50% value of the first pressurizing pad of 3,000 kPa or more.

[0085] The fact that the CFD 50% value or the CFD 60% value of the first pressure pad is greater than the CFD 50% value or the CFD 60% value of the second pressure pad may mean that the first pressure pad has higher firmness and lower softness than the second pressure pad.

[0086] In a battery cell pressurizing pad according to one embodiment of the present invention, the first pressurizing pad and the second pressurizing pad may be any one of polytetrafluoroethylene (PTFE), silicone, organic rubber, polyurethane, polystyrene, polyethylene, polypropylene, ethylene vinyl acetate (EVA), and polyethylene terephthalate (PET), but are not limited to these examples.

[0087] A battery cell pressurizing pad according to one embodiment of the present invention may be used by being attached to one surface of a pressurizing jig for pressing a battery cell. In addition, the battery cell pressurizing pad may be used by contacting the surface of the battery cell with the battery cell pressurizing pad before pressing the battery cell, and then being pressed by the pressurizing jig. Therefore, there is no limitation on the form of use of the battery cell pressurizing pad, and there is also no limitation on the type of jig for pressing the battery cell.

[0088] One embodiment of the present invention can provide a battery cell pressurizing device including the battery cell pressurizing pad. There is no limitation on the shape of the battery cell pressurizing device.

[0089] The above battery cell pressurizing device can allow the battery cells to be placed between the battery cell pressurizing pads. Accordingly, when pressurizing the battery cells, uniform pressure can be applied to the battery cells by the battery cell pressurizing pads according to an embodiment of the present invention.

[0090] Additionally, the battery cell pressurizing device can uniaxially pressurize or isotropically pressurize the battery cell.

[0091] Hereinafter, preferred examples are presented to help understand the present invention, but the following examples are only illustrative of the present invention, and it is obvious to those skilled in the art that various changes and modifications are possible within the scope and technical idea of ​​the present invention, and it is also natural that such changes and modifications fall within the scope of the appended patent claims.

[0092]

[0093] Example 1

[0094] A pressure pad was manufactured by laminating a 0.5 mm polytetrafluoroethylene (PTFE) layer and a 0.3 mm silicone layer.

[0095] Example 2

[0096] A pressurized pad was manufactured by laminating a 0.5 mm polytetrafluoroethylene (PTFE) layer and a 0.3 mm silicone layer, and each pressurized pad was manufactured so that the CFD 60% value was 4,000 kPa or more.

[0097] Comparative Example 1

[0098] A pressure pad was manufactured using only 0.5 mm polytetrafluoroethylene (PTFE).

[0099] Comparative Example 2

[0100] A pressure pad was manufactured using only a 0.3 mm silicone layer.

[0101] Comparative Example 3

[0102] A pressure pad was manufactured using only 0.5 mm polyurethane (PU).

[0103] Comparative Example 4

[0104] A pressure pad was manufactured using only 1.0 mm polyurethane (PU).

[0105] Comparative Example 5

[0106] A pressure pad was manufactured using a 0.5 mm polytetrafluoroethylene (PTFE) layer and a 0.3 mm silicone layer, but the pressure pad was manufactured using a different lamination order from that manufactured in the above example.

[0107] Comparative Example 6

[0108] A pressurized pad was manufactured using 0.5 mm polytetrafluoroethylene (PTFE) and 0.2 mm polyurethane (PU), and each pressurized pad was manufactured so that the CFD 60% value was 4,000 kPa or more.

[0109] Comparative Example 7

[0110] A pressure pad was manufactured using a 1.0 mm polytetrafluoroethylene (PTFE) layer and a 0.3 mm silicone layer.

[0111]

[0112] Experimental Example 1: Battery Cell Performance Evaluation

[0113] The battery cell was pressurized using the pressurizing pad, spring jig, and torque wrench manufactured in Example 1, Comparative Examples 1, and 2 above. At this time, the battery cell performance, such as the cell charge / discharge rate and cycle maintenance rate, was evaluated when the cell was fastened. The battery cell performance is shown in FIGS. 3 and 4.

[0114] Figure 3 is a diagram showing the charge / discharge rate of a battery cell pressed using a battery cell pressurizing pad according to one embodiment of the present invention and comparative examples 1 and 2. Here, C-rate is a value indicating the speed at which a battery is charged or discharged, and means the charge / discharge rate.

[0115] Referring to FIG. 3, it was confirmed that the charge / discharge rate of the battery cell pressed using the battery cell pressurizing pad according to Example 1 was lower than the charge / discharge rate at high rate (1C) of the battery cell pressed using the battery cell pressurizing pad according to Comparative Example 1, and higher than the charge / discharge rate of the battery cell pressed using the battery cell pressurizing pad according to Comparative Example 2.

[0116] FIG. 4 is a diagram showing the cycle maintenance rate of a battery cell pressed using a battery cell pressurizing pad according to Example 1 and Comparative Examples 1 and 2 of the present invention.

[0117] Referring to FIG. 4, it was confirmed that the cycle retention rate of the battery cell pressed using the battery cell pressurizing pad according to Example 1 decreased at a constant rate as the cycle was repeated multiple times, while the cycle retention rate of the battery cell pressed using the battery cell pressurizing pad according to Comparative Example 1 showed an unstable retention rate, with a short occurring in the initial cycle, and the cycle retention rate of the battery cell pressed using the battery cell pressurizing pad according to Comparative Example 2 increased and then decreased again as the cycle was repeated multiple times.

[0118] Therefore, it was found that using two types of pressurizing pads, such as the battery cell pressurizing pad according to Example 1, compared to using only one pressurizing pad, such as the battery cell pressurizing pad according to Comparative Examples 1 and 2, improved the charge / discharge rate and cycle maintenance rate of the cell by applying a uniform pressure when pressing the battery cell.

[0119] Experimental Example 2: Battery Cell Performance Evaluation

[0120] The battery cell was pressurized using the pressurizing pad, spring jig, and torque wrench manufactured in Example 1, Comparative Examples 3, and 4. At this time, the battery cell performance, such as the cell charge / discharge rate and cycle maintenance rate, was evaluated when the cell was fastened. The battery cell performance is shown in FIGS. 5 and 6.

[0121] Figure 5 is a diagram showing the charge / discharge rate of a battery cell pressed using a battery cell pressurizing pad according to Example 1, Comparative Examples 3 and 4 of the present invention. Here, C-rate is a value indicating the speed at which a battery is charged or discharged, and means the charge / discharge rate.

[0122] Referring to FIG. 5, it was confirmed that the charge / discharge rate of the battery cell pressed using the battery cell pressurizing pad according to Example 1 was somewhat lower than the charge / discharge rate at high rate (1C) of the battery cell pressed using the battery cell pressurizing pad according to Comparative Example 3, and higher than the charge / discharge rate of the battery cell pressed using the battery cell pressurizing pad according to Comparative Example 4.

[0123] FIG. 6 is a diagram showing the cycle maintenance rate of a battery cell pressed using a battery cell pressurizing pad according to Example 1, Comparative Examples 3 and 4 of the present invention.

[0124] Referring to FIG. 6, it was confirmed that the cycle life of a battery cell pressed using a battery cell pressurizing pad according to Example 1 decreased at a constant rate as multiple cycles were repeated, whereas the cycle life of a battery cell pressed using a battery cell pressurizing pad according to Comparative Example 3 showed a short circuit at about 50 cycles, and the cycle life of a battery cell pressed using a battery cell pressurizing pad according to Comparative Example 4 showed a large deviation as multiple cycles were repeated.

[0125] Therefore, it was found that using two types of pressure pads with different softness and firmness, such as the battery cell pressure pad according to Example 1, rather than using only a pressure pad with low softness, such as the battery cell pressure pad according to Comparative Examples 3 and 4, allows for uniform pressure to be applied when pressing the battery cell, thereby improving the charge / discharge rate and cycle maintenance rate of the cell.

[0126] Experimental Example 3: Battery Cell Performance Evaluation

[0127] The battery cell was pressurized using the pressurizing pad, spring jig, and torque wrench manufactured in Example 1 and Comparative Example 5. At this time, the battery cell performance, such as the cell charge / discharge rate and cycle maintenance rate, was evaluated when the cell was fastened. The battery cell performance is shown in FIGS. 7 and 8.

[0128] Figure 7 is a diagram showing the charge / discharge rate of a battery cell pressed using a battery cell pressurizing pad according to Example 1 and Comparative Example 5 of the present invention. Here, C-rate is a value indicating the speed at which a battery is charged or discharged, and means the charge / discharge rate.

[0129] Referring to FIG. 7, it was confirmed that the charge / discharge rate of the battery cell pressed using the battery cell pressurizing pad according to Comparative Example 5 was significantly lower than the charge / discharge rate at high rate (1C) of the battery cell pressed using the battery cell pressurizing pad according to Example 1.

[0130] FIG. 8 is a diagram showing the cycle maintenance rate of a battery cell pressed using a battery cell pressurizing pad according to Example 1 and Comparative Example 5 of the present invention.

[0131] Referring to FIG. 8, it was confirmed that the cycle maintenance rate of the battery cell pressed using the battery cell pressurizing pad according to Example 1 had a somewhat smaller deviation from the cycle maintenance rate of the battery cell pressed using the battery cell pressurizing pad according to Comparative Example 5 over the course of multiple cycles.

[0132] Therefore, it was found that when the stacking order of the first pressure pad and the second pressure pad was changed, such as in the battery cell pressure pad according to Comparative Example 5, the charge / discharge rate of the battery cell at high rate (1C) was significantly reduced.

[0133] Experimental Example 4: CFD (Compression Force Deflection) Measurement of Battery Cell Pressurized Pads

[0134] Among the pressure pads manufactured in Example 1, samples of polytetrafluoroethylene used as the first pressure pad and the silicone layer used as the second pressure pad, and 50 mm x 50 mm samples of the pressure pads according to Comparative Examples 3 and 4 were prepared. The samples were placed on the lower compression plate of a compression tester, and the stress according to the degree of compression was measured at a speed of 50 mm per minute. That is, the CFD values ​​of the pressure pads were measured through the ASTM D3574 standard test. The measured CFD values ​​of the pressure pads are shown in Table 1 below.

[0135] Peak Stress(kPa)CFD 10%(kPa)CFD 20%(kPa)CFD 30%(kPa)CFD 40%(kPa)CFD 50%(kPa)CFD 60%(kPa)CFD 70%(kPa)CFD 80%(kPa)First pressure pad17,7821683867911,5703,2567,447--Second pressure pad17,5521954407721,2852,2414,2789,211-Comparative example37,754243548701162377236,211Comparative example45,773.546721021472223838784,430

[0136] Experimental Example 5: Battery Cell Performance Evaluation The battery cell was pressurized using the pressurizing pads manufactured in Example 2 and Comparative Example 6. At this time, the battery cell performance, such as the cell charge / discharge rate and cycle maintenance rate, was evaluated when the cell was fastened. The battery cell performance is shown in FIGS. 10 and 11.

[0137] FIG. 9 is a diagram showing a compression curve of a pressurized pad according to Comparative Example 6 of the present invention. The compression curve graph of the PU PAD used in Comparative Example 2 shows that the stress increases as the compression ratio increases. In particular, when the compression ratio is 40% or less, the stress is 2 MPa or less, but it increases sharply to 10 MPa around 50%.

[0138] Figure 10 is a diagram showing the charge / discharge rate of a battery cell pressed using a battery cell pressurizing pad according to Example 2 and Comparative Example 6 of the present invention. Here, C-rate is a value indicating the speed at which a battery is charged or discharged, and means the charge / discharge rate.

[0139] Referring to FIG. 10, it was confirmed that the charge / discharge rate of the battery cell pressed using the battery cell pressurizing pad according to Example 2 was about 4% higher than the charge / discharge rate at high rate (1C) of the battery cell pressed using the battery cell pressurizing pad according to Comparative Example 6.

[0140] FIG. 11 is a diagram showing the cycle maintenance rate of a battery cell pressed using a battery cell pressurizing pad according to Example 2 and Comparative Example 6 of the present invention.

[0141] Referring to FIG. 11, the cycle retention rate of the battery cell pressed using the battery cell pressurizing pad according to Example 2 decreased at a constant rate as the cycles were repeated multiple times, whereas the cycle retention rate of the battery cell pressed using the battery cell pressurizing pad according to Comparative Example 6 showed a similar pattern in the initial cycles, but it was confirmed that there was a difference of about 5% or more as the cycles increased.

[0142] Therefore, even when the value of CFD 60% is used to be 4,000 kPa or more under the same conditions as Comparative Example 6, it was found that using the battery cell pressurizing pad according to Example 2 improved the charge / discharge rate and cycle maintenance rate of the cell by applying a uniform pressure when pressurizing the battery cell.

[0143] Experimental Example 6: Battery Cell Performance Evaluation

[0144] A 0.5 mm battery cell was pressed using the pressurizing pad manufactured in Example 1 and Comparative Example 7. At this time, the battery cell performance, such as the cell charge / discharge rate and cycle maintenance rate, was evaluated when the cell was fastened. The battery cell performance is shown in FIGS. 12 and 13.

[0145] Figure 12 is a diagram showing the charge / discharge rate of a battery cell pressed using a battery cell pressurizing pad according to Example 1 and Comparative Example 7 of the present invention. Here, C-rate is a value indicating the speed at which a battery is charged or discharged, and means the charge / discharge rate.

[0146] Referring to FIG. 12, it was confirmed that the charge / discharge rate of the battery cell pressed using the battery cell pressurizing pad according to Example 7 was significantly lower than the charge / discharge rate at high rate (1C) of the battery cell pressed using the battery cell pressurizing pad according to Example 1.

[0147] FIG. 13 is a diagram showing the cycle maintenance rate of a battery cell pressed using a battery cell pressurizing pad according to Example 1 and Comparative Example 7 of the present invention.

[0148] Referring to FIG. 13, it was confirmed that the cycle maintenance rate of the battery cell pressed using the battery cell pressurizing pad according to Example 1 decreased at a constant rate as the cycles were repeated multiple times, whereas the cycle maintenance rate of the battery cell pressed using the battery cell pressurizing pad according to Comparative Example 7 decreased rapidly within 10 cycles.

[0149] Therefore, it was found that when the thickness of the first pressure pad exceeds a certain thickness, such as the battery cell pressure pad according to Comparative Example 7, the charge / discharge rate and cycle maintenance rate of the battery cell decrease.

[0150] Hereinafter, an embodiment of the present invention has been described by way of example, but the present invention is not intended to be limited to the above-described embodiment. Those skilled in the art will be able to appropriately modify an embodiment of the present invention by omitting, changing, replacing all or part of the configuration of the present invention, or adding other configurations, with reference to this specification and the attached drawings, without departing from the technical spirit of the present invention. The terms and expressions of this specification should be interpreted broadly and not in a limiting sense. In this specification, the expression "include" does not exclude the presence or addition of one or more other components in addition to the mentioned components.

[0151] In this specification, expressions in the singular include the plural unless explicitly excluded by context.

[0152] Each of the embodiments exemplarily described herein can be combined with one another, and unless contradictory, the content described in a particular embodiment can be equally applied to other embodiments even if not described in the other embodiments.

[0153] [Explanation of symbols]

[0154] 10: Battery cell

[0155] 20: Pressurized jig

[0156] 101: First pressure pad

[0157] 101-1: No. 1-1 pressurized pad

[0158] 101-2: 1-2 pressurized pad

[0159] 102: Second pressure pad

[0160] 102-1: No. 2-1 pressurized pad

[0161] 102-2: No. 2-2 pressurized pad

Claims

1. In a battery cell pressurizing pad that pressurizes a battery cell in which an electrode and a solid electrolyte are laminated, A first pressure pad that contacts one side of the battery cell and presses the one side of the battery cell; and A battery cell pressing pad, comprising: a second pressing pad laminated on the first pressing pad and in contact with one side of a pressing jig; 2. In paragraph 1, The above first pressure pad, Pressurize both sides with the above battery cells in between, A first-first pressing pad for pressing one side of the battery cell; and A battery cell pressurizing pad, comprising a first and second pressurizing pads for pressing the other side of the battery cell.

3. In paragraph 2, The above second pressure pad, A 2-1 pressure pad laminated on the 1-1 pressure pad; and including a second-second pressing pad laminated on the first-second pressing pad; The above 2-1 pressure pad and the 2-2 pressure pad are battery cell pressure pads that each contact one side of a pressure jig facing each other.

4. In paragraph 1, A battery cell pressurizing pad, wherein the CFD (Compression Force Deflection) 60% value of the first pressurizing pad and the second pressurizing pad is 4,000 kPa or more.

5. In paragraph 1, A battery cell pressurizing pad, wherein the CFD 60% value of the first pressurizing pad is greater than the CFD 60% value of the second pressurizing pad.

6. In paragraph 1, A battery cell pressurizing pad, wherein the CFD 60% value of the first pressurizing pad is 7,000 kPa or more.

7. In paragraph 1, The thickness of the above battery cell (T c ) and the thickness (T1) of the first pressing pad is 1: 0.01 to 0.5, a battery cell pressing pad.

8. In paragraph 1, The thickness (T1) of the first pressure pad satisfies the following equation 1: [Formula 1] T1> T p - T u In the above equation 1, T p is the thickness of the positive electrode within the battery cell, T u is the thickness of the pouch film inside the battery cell.

9. In paragraph 1, A battery cell pressurizing pad, wherein when the first pressurizing pad is compressed multiple times at a strain of 80% based on the initial thickness, the thickness of the first pressurizing pad is reduced by 60% or more based on the initial thickness.

10. In paragraph 1, A battery cell pressurizing pad, wherein the CFD 50% value of the first pressurizing pad and the second pressurizing pad is 2,000 kPa or more.

11. In paragraph 1, A battery cell pressurizing pad, wherein the CFD 50% value of the first pressurizing pad is greater than the CFD 50% value of the second pressurizing pad.

12. In paragraph 1, A battery cell pressurizing pad, wherein the CFD (Compression Force Deflection) 50% value of the first pressurizing pad is 3,000 kPa or more.

13. A battery cell pressurizing device comprising a battery cell pressurizing pad according to any one of claims 1 to 12.

14. In paragraph 13, A battery cell pressurizing device, wherein battery cells are placed between the above battery cell pressurizing pads.

15. In paragraph 14, A battery cell pressurizing device that uniaxially or isotropically pressurizes the above battery cell.

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