Limiting mold for cycle test of thick laminated battery core of sulfide solid-state battery

Abstract

The utility model provides a limit mould for sulfide solid-state battery thick laminated cell cycle test, which comprises a pressing module and a frame body, the pressing module is embedded in the frame body, the frame body is provided with a plurality of adjusting grooves, fasteners are in sliding fit with the groove walls of the adjusting grooves, and the pressing module and the fasteners can move up and down along the vertical direction; multiple layers of battery cells are stacked in the accommodating cavity, and avoiding grooves matched with tabs of the battery cells are formed in the sides, close to each other, of the two frame bodies. According to the utility model, the rigid mold is used for applying inward binding force to the battery cell, counteracting extension stress, contacting the inner wall of the mold with the edge of the battery cell, applying uniform lateral pressure and constraining the deformation direction, so that the tearing rate of the pole piece is greatly reduced, the structural integrity of the battery cell is improved, and the interface impedance after circulation is reduced; the pressing module and the frame body are matched to form an adjustable limiting structure, the size of the mold can be adjusted according to the number of layers or the thickness of the battery cells, and the mold can adapt to the battery cells with different thicknesses and different specifications.

Description

Technical Field

[0001] This utility model relates to the field of battery testing technology, specifically to a limiting mold for cycle testing of thick-layer sulfide solid-state battery cells. Background Technology

[0002] As the next generation of energy storage technology, all-solid-state lithium-ion batteries are revolutionizing the energy storage field due to their groundbreaking performance advantages. Compared to traditional liquid lithium-ion batteries, this technology completely replaces flammable and volatile organic electrolytes with a solid-state electrolyte system. This structural change not only increases the energy density to a theoretical level of 400-500 Wh / kg (approximately twice that of current liquid batteries), but also achieves a breakthrough in battery intrinsic safety by eliminating potential hazards such as electrolyte leakage and thermal runaway. Simultaneously, thanks to the effective suppression of lithium dendrite growth by the solid-state system, the battery cycle life can exceed tens of thousands of cycles, providing a reliable solution for long-term use in electric vehicles and grid-scale energy storage systems.

[0003] In solid-state electrolyte material systems, sulfide-based electrolytes have become a research hotspot due to their unique performance advantages. These materials can achieve 10⁻⁶ ppm at room temperature. -2 -10 -3 With ultra-high lithium-ion conductivity on the order of S / cm, comparable to liquid electrolytes, and excellent ductility (Young's modulus of approximately 10 GPa), it can form a low-impedance interface with electrode materials through cold pressing. Notably, the sulfide electrolyte exhibits significantly better chemical compatibility with high-nickel cathodes and silicon-carbon anodes than oxide systems. In-situ interface modification technology can further reduce interfacial side reactions by more than 80%, but its cycle testing requires a high-pressure environment. When the number of layers in a pouch cell is large (e.g., >10 layers) and its thickness is large (e.g., >5 mm), the battery electrodes will extend outwards under pressure during testing, leading to the following problems:

[0004] (1) Electrode tearing: The epitaxial force exceeds the mechanical strength of the electrode, causing cracks or even breakage;

[0005] (2) Cell structure damage: internal interface delamination, ion transport path obstructed;

[0006] (3) Performance and safety decline: capacity decay accelerates, internal resistance increases, and the risk of thermal runaway increases.

[0007] Existing solutions often circumvent the problem by reducing testing pressure or decreasing the number of stacks, but at the expense of cell capacity and practical application value.

[0008] A Chinese patent with publication number CN220137334U discloses a testing fixture for soft-pack battery cells, including a base plate, a lower clamping plate, a movable plate, a top plate, a connecting rod, a nut, a limiting post, a pressure sensor, a first displacement sensor, and a second displacement sensor. The probe of the first displacement sensor passes through the movable plate and the elastic filling medium and abuts against the upper surface of the battery cell, while the probe of the second displacement sensor abuts against the upper surface of the movable plate.

[0009] Existing testing fixtures are prone to electrode tearing and structural damage under high voltage, and thick-layer cells cannot achieve high-capacity designs. Therefore, there is a need for a limiting mold for cycle testing of thick-layer sulfide solid-state battery cells. This mold applies an inward binding force to the cell to counteract the epitaxial stress, thereby reducing the electrode tearing rate, ensuring the structural integrity of the cell, and allowing the mold size to be adjusted according to the number or thickness of the cell layers to accommodate different cell specifications. Utility Model Content

[0010] To address the shortcomings of existing technologies, the purpose of this invention is to provide a limiting mold for cycle testing of thick-layer tandem cells in sulfide solid-state batteries.

[0011] According to the present invention, a limiting mold for cycle testing of thick stacked sulfide solid-state battery cells includes: a clamping module and a frame. The clamping module is embedded in the frame, and the four sides of the clamping module are fitted to the inner side of the frame. The frame is provided with multiple adjustment slots. The frame is connected to the clamping module through the adjustment slots by fasteners to form a semi-mold. The fasteners slide with the slot walls of the adjustment slots. The clamping module and the fasteners can move up and down in the vertical direction.

[0012] The upper and lower half molds are mirror images of each other and close to each other to form a cavity that matches the size of the battery cell. Multiple battery cells are stacked in the cavity. The two frames are provided with clearance grooves that match the tabs of the battery cells on their close sides. The tabs are placed in the through holes formed by the two clearance grooves.

[0013] Two half-molds containing the battery cell are fastened together by connectors to form a limiting mold. The limiting mold is placed on a pressurizing device, and the pressing module is driven by the pressurizing device to move vertically to press the battery cell.

[0014] Preferably, there is a gap between the inner sidewall of the frame and the edge of the battery cell, and the gap does not exceed 0.5 mm.

[0015] Preferably, a plurality of fastening holes are evenly provided on the two long sidewalls of the clamping module, and the fastening holes are provided in a one-to-one correspondence with the adjustment grooves. The fasteners pass through the adjustment grooves and are fixedly connected to the fastening holes.

[0016] Preferably, the center of the clearance groove has a protrusion that matches the gap in the center of the electrode lug. The protrusion is arc-shaped, and when the two frames are fastened together, the two protrusions abut against each other.

[0017] Preferably, a fastening hole is provided at the center of the two short sidewalls of the clamping module, and the fastening hole is provided in correspondence with the adjustment groove. The diameter of the fastening hole and the adjustment groove located on the side of the clearance groove does not exceed the width of the protrusion.

[0018] Preferably, when the fastener moves to any position in the adjustment groove, the clamping module and the frame remain inseparable.

[0019] Preferably, each of the four corners of the frame is provided with a connecting lug, and two of the connecting lugs are fastened together by bolts.

[0020] Preferably, the clamping module comprises a stainless steel module.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] This invention applies an inward binding force to the battery cell using a rigid mold to counteract the epitaxial stress. The inner wall of the mold contacts the edge of the battery cell, applying uniform lateral pressure to constrain the deformation direction, which significantly reduces the electrode tearing rate, improves the structural integrity of the battery cell, and reduces the interface impedance after cycling. This effectively solves the problem of electrode tearing and structural damage caused by the epitaxial growth of the battery cell under high voltage. An adjustable limiting structure is formed by the clamping module and the frame, and the mold size can be adjusted according to the number of battery cell layers or thickness, which can accommodate battery cells of different thicknesses and specifications. Attached Figure Description

[0023] Other features, objects, and advantages of this invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0024] Figure 1 This utility model mainly embodies the exploded view of the limiting mold used for cycle testing of thick stacked cells of sulfide solid-state batteries;

[0025] Figure 2 This utility model mainly illustrates the structure of the limiting mold used in the cycle testing of thick-layer tandem cells for sulfide solid-state batteries.

[0026] Figure label:

[0027] Detailed Implementation

[0028] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0029] like Figure 1 and 2 As shown, a limiting mold for cycle testing of thick-layer sulfide solid-state battery cells according to this utility model includes: a clamping module 3 and a frame 4. The clamping module 3 is embedded in the frame 4, and the four sides of the clamping module 3 are fitted to the inner sidewalls of the frame 4. The frame 4 is provided with multiple adjustment grooves 5. The frame 4 is connected to the clamping module 3 through the adjustment grooves 5 by fasteners to form a semi-mold. The fasteners slide against the groove walls of the adjustment grooves 5, and the clamping module 3 and the fasteners can move up and down in the vertical direction. The two half-molds are mirror images of each other and are close to each other to form a cavity that matches the size of the battery cell 6. The multi-layer battery cells 6 are stacked in the cavity. The two frames 4 are provided with clearance grooves 8 that match the tabs 7 of the battery cell 6 on their close sides. The tabs 7 are placed in the through holes formed by the two clearance grooves 8. The two half-molds containing the battery cells 6 are fastened together by connectors to form a limiting mold. The limiting mold is placed on a pressurizing device. The pressing module 3 is driven by the pressurizing device to move vertically to press the battery cell 6.

[0030] The frame 4 is the core component providing lateral restraint and is typically made of a high-rigidity, corrosion-resistant alloy. The frame 4 and the clamping module 3 are secured together with fasteners to provide even stronger lateral restraint. The adjustment slot 5 is a long, circular slot that, when used with fasteners, allows for vertical adjustment of the clamping module 3 to accommodate cells 6 with different layer counts (thicknesses).

[0031] There is a gap between the inner wall of the frame 4 and the edge of the battery cell 6, which does not exceed 0.5mm. The inner cavity size of the frame 4 is slightly larger than the size of the battery cell 6 (generally a 0.5mm gap is reserved on one side), and the inner wall is smooth so that it can fit the battery cell 6 evenly. For example, if the size of the battery cell 6 is 53*108mm, then the inner cavity size of the limiting mold is 54*109mm.

[0032] Multiple fastening holes 2 are evenly arranged on the two long side walls of the clamping module 3. The fastening holes 2 are arranged one-to-one with the adjustment grooves 5. The fasteners pass through the adjustment grooves 5 and are fixedly connected to the fastening holes 2.

[0033] The clearance groove 8 is used to prevent the electrode lug 7 from being crushed when the upper and lower frames 4 are joined. The middle of the clearance groove 8 has a protrusion that matches the gap in the middle of the electrode lug 7. The protrusion is arc-shaped, and the two protrusions abut against each other when the two frames 4 are fastened together.

[0034] Fastening holes 2 are provided at the center of the two short side walls of the clamping module 3. The fastening holes 2 are corresponding to the adjustment grooves 5. The diameters of the fastening holes 2 and the adjustment grooves 5 located on the side of the clearance groove 8 do not exceed the width of the protrusion.

[0035] When the fastener moves to any position in the adjustment slot 5, the clamping module 3 and the frame 4 will never separate.

[0036] Each of the four corners of the frame 4 is provided with a connecting lug 1. The two connecting lugs 1 are fastened together by bolts, which are used to fix the upper frame, the battery cell 6 and the lower frame together after assembly.

[0037] The clamping module 3 is made of 316 stainless steel with a polished surface. Its size is the same as the inner wall size of the frame 4, and the two fit together as precisely as possible.

[0038] The loop testing method of this application includes the following steps:

[0039] Step S1: Insert the thick-layer battery cell 6 to be tested into the inner cavity of the limiting mold to ensure uniform contact around the perimeter.

[0040] Step S2: Fasteners are used to make the clamping module 3 and the inner wall of the frame 4 tightly adhere to the battery cell 6;

[0041] Step S3: Place the entire assembly on a tablet press and apply positive pressure;

[0042] Step S4: Start the cyclic testing equipment; 0.1C rate, 3 cycles; 0.5C rate, 100 cycles; 2.5-4.3V voltage range.

[0043] Step S5: After the test is completed, disassemble the mold and check the deformation and performance indicators of the battery cell.

[0044] This application is further illustrated by the following two sets of experiments.

[0045] Group 1: Limiting mold vs. moldless group:

[0046] Test conditions: 9-layer laminated battery cell (6mm thickness), test pressure 30MPa, 100 cycles.

[0047] Result comparison:

[0048] index Limiting mold assembly moldless assembly Electrode tear rate 5％ 85％ Capacity retention (100 weeks) 92％ 65％ Interfacial impedance growth +15％ +50％

[0049] The second group, verification of thick-layer battery cells;

[0050] Cell specifications: 15-layer lamination (5mm thickness), fixed using a limiting mold.

[0051] Cyclic performance: Capacity retention >88% after 200 cycles, with no visible cracks on the electrode.

[0052] This application applies an inward binding force to the battery cell 6 using a rigid mold to counteract the epitaxial stress. The inner wall of the mold contacts the edge of the battery cell, applying uniform lateral pressure to constrain the deformation direction. This reduces the electrode tearing rate to >80%, improves the structural integrity of the battery cell 6, and reduces the interface impedance by 30% after cycling. This effectively solves the problem of electrode tearing and structural damage caused by the epitaxy of the battery cell under high voltage.

[0053] This application forms an adjustable limiting structure by using the clamping module 3 and the frame 4 together. The mold size can be adjusted according to the number of layers or thickness of the battery cell 6, which can adapt to battery cells 6 of different thicknesses and specifications, and supports the stacking number to be increased to 20 layers (thickness > 8mm).

[0054] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0055] The specific embodiments of this utility model have been described above. It should be understood that this utility model is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the substantive content of this utility model. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A limiting mold for cycle testing of thick-layer sulfide solid-state battery cells, characterized in that, include: A clamping module (3) and a frame (4) are provided. The clamping module (3) is embedded in the frame (4), and the four sides of the clamping module (3) are fitted to the inner side of the frame (4). The frame (4) is provided with multiple adjustment slots (5). The frame (4) is connected to the clamping module (3) through the adjustment slots (5) by fasteners to form a semi-mold. The fasteners slide with the slot walls of the adjustment slots (5). The clamping module (3) and the fasteners can move up and down in the vertical direction. The upper and lower half molds are mirror images of each other and close to each other to form a cavity that matches the size of the battery cell (6). Multiple battery cells (6) are stacked in the cavity. The two frames (4) are provided with clearance grooves (8) that match the tabs (7) of the battery cell (6) on their close sides. The tabs (7) are placed in the through holes formed by the two clearance grooves (8). Two half molds containing the battery cell (6) are fastened together by connectors to form a limiting mold. The limiting mold is placed on a pressurizing device. The pressing module (3) is driven by the pressurizing device to move vertically to press the battery cell (6).

2. The limiting mold for cycle testing of thick-layer sulfide solid-state battery cells as described in claim 1, characterized in that, There is a gap between the inner wall of the frame (4) and the edge of the battery cell (6), and the gap does not exceed 0.5 mm.

3. The limiting mold for cycle testing of thick-layer sulfide solid-state battery cells as described in claim 1, characterized in that, Multiple fastening holes (2) are evenly arranged on the two long side walls of the clamping module (3). The fastening holes (2) are arranged in a one-to-one correspondence with the adjustment groove (5). The fastener passes through the adjustment groove (5) and is fixedly connected to the fastening hole (2).

4. The limiting mold for cycle testing of thick-layer sulfide solid-state battery cells as described in claim 1, characterized in that, The center of the clearance groove (8) has a protrusion that matches the gap in the center of the tab (7). The protrusion is arc-shaped and the two protrusions abut against each other when the two frames (4) are fastened together.

5. The limiting mold for cycle testing of thick-layer sulfide solid-state battery cells as described in claim 4, characterized in that, Fastening holes (2) are provided at the center of the two short side walls of the clamping module (3). The fastening holes (2) are provided in correspondence with the adjustment grooves (5). The diameters of the fastening holes (2) and the adjustment grooves (5) located on the side of the clearance groove (8) do not exceed the width of the protrusion.

6. The limiting mold for cycle testing of thick-layer sulfide solid-state battery cells as described in claim 1, characterized in that, When the fastener moves to any position of the adjustment groove (5), the clamping module (3) and the frame (4) remain inseparable.

7. The limiting mold for cycle testing of thick-layer sulfide solid-state battery cells as described in claim 1, characterized in that, The frame (4) is provided with connecting ears (1) at each of its four corners, and the two connecting ears (1) are fastened together by bolts.

8. The limiting mold for cycle testing of thick-layer sulfide solid-state battery cells as described in claim 1, characterized in that, The clamping module (3) includes a stainless steel module.

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