A pressurizing device, method, and cylindrical solid-state battery

Abstract

The application provides a pressing device and method of a cylindrical solid-state battery and the cylindrical solid-state battery, and belongs to the technical field of new energy battery manufacturing. The pressing device comprises a rack, a center tube, an internal pressing assembly and an external pressing assembly. The rack is used for bearing the cylindrical battery. The center tube serves as a supporting reel in the winding process of the cylindrical battery roll core and can generate a preset radial deformation. The internal pressing assembly is connected to the rack and can be telescopically extended into the center tube, and is used for applying a radial pressure to the tube wall of the center tube to drive the center tube to generate a first radial pressure on the roll core of the cylindrical battery. The external pressing assembly is connected with the rack and is used for applying a radial pressure to the shell of the cylindrical battery to drive the shell to apply a second radial pressure on the roll core. In this way, the roll core can form a uniform and stable high pressure between the film sheets through internal and external double extrusion, so as to improve the rate performance, cycle stability and service life of the cylindrical battery.

Description

Technical Field

[0001] This application relates to the field of new energy battery manufacturing technology, and in particular to a pressurization device, method and cylindrical solid-state battery. Background Technology

[0002] Cylindrical solid-state batteries offer advantages such as high energy density, high safety, and a wide operating range, making them an important development direction for power batteries. Unlike liquid batteries where the electrolyte can spontaneously wet and fill gaps, solid-state batteries have microscopic roughness at the solid-solid interface. If the contact is not tight, it will lead to extremely high interfacial contact resistance, severely hindering the transport of lithium ions and significantly reducing the battery's rate performance and capacity. In addition, during charge-discharge cycles, the electrode materials also undergo periodic volume expansion and contraction (i.e., the breathing effect). If the initial interfacial bonding force is insufficient or the pressure distribution is uneven, it can easily lead to an increase in interfacial resistance, which in turn causes a sharp increase in the battery's internal resistance or even failure, seriously affecting the battery's cycle life.

[0003] In related technologies, the pressure application approach used in pouch cells ensures the adhesion between the film layers of the core by applying radial pressure to one side of the cylindrical battery casing. However, since the core of a solid-state battery requires higher pressure (10MPa) to charge and discharge, applying unidirectional pressure to the outside of the core can easily cause the core to become eccentric or shifted within the cylindrical casing, resulting in insufficient overall interfacial pressure from the outside to the inside of the core and extremely uneven distribution of interfacial pressure. Summary of the Invention

[0004] This application provides a pressurizing device, method, and cylindrical solid-state battery to at least solve the problems in the prior art.

[0005] To achieve the above objectives, this application provides the following technical solution: a pressurizing device for cylindrical solid-state batteries, used to extrude the core of cylindrical batteries; the pressurizing device includes a frame, a central tube, an internal pressurizing assembly, and an external pressurizing assembly;

[0006] The frame is used to support the cylindrical battery, and the central tube serves as a support shaft for the winding process of the cylindrical battery core and can generate a preset radial deformation.

[0007] The internal pressurization assembly is connected to the frame and extends retractably into the central tube to apply radial pressure to the tube wall of the central tube, thereby driving the central tube to generate a first radial pressure on the core of the cylindrical battery.

[0008] An external pressurization assembly is connected to the frame and is used to apply radial pressure to the casing of the cylindrical battery, driving the casing to apply a second radial pressure to the winding core; wherein,

[0009] The internal and external pressurizing components work together to allow the core to adjust the contact state of the core interface under the bidirectional compression of the first radial pressure and the second radial pressure.

[0010] In one embodiment, the internal pressurization assembly includes a first driving member, a transmission member, and multiple arc-shaped lobes;

[0011] Each arc-shaped petal extends along the axial direction of the central tube. Multiple arc-shaped petals are located inside the central tube and are circumferentially spaced around the central axis of the central tube. Multiple arc-shaped petals surround and form an inner cavity.

[0012] The transmission components are located within the inner cavity and are respectively connected to the first driving component and each arc-shaped petal; wherein,

[0013] The first driving component is used to drive the transmission component to move, so that the transmission component drives multiple arc-shaped petals to move radially in sync. When the multiple arc-shaped petals move radially in sync, they push against the wall of the central tube together to cause a preset deformation, so that the central tube presses against the inner wall of the core with the first radial pressure.

[0014] In one embodiment, the transmission component includes a central rod and multiple sets of connecting rods, the number of sets of connecting rods being the same as the number of arc-shaped lobes;

[0015] The central rod is coaxially arranged with the central tube. Each set of connecting rods is inclined relative to the central rod. One end of each set of connecting rods is close to the first driving member and rotatably connected to the central rod, while the other end is away from the first driving member and rotatably connected to a corresponding arc-shaped petal. The first driving member is connected to one end of the central rod.

[0016] In one embodiment, the transmission component further includes a fixed tube and multiple sets of hinge rods, the number of sets of hinge rods being the same as the number of arc-shaped lobes;

[0017] One end of each set of hinge rods is rotatably connected to the fixed tube, and the other end is rotatably connected to the arc-shaped petal. The hinge rods and connecting rods are symmetrically arranged about a radial plane of the arc-shaped petal.

[0018] The fixed tube is slidably sleeved on the central rod. A stop is provided at one end of the fixed tube near the first driving member. The stop protrudes from the fixed tube in the radial direction and is used to abut against the external pressure assembly or frame.

[0019] In one embodiment, the central tube is made of a ductile metal material, which allows it to undergo plastic deformation when an internal pressure assembly applies a radial expansion force, and retains its expanded shape when the radial expansion force is removed; or...

[0020] The central tube is made of an elastic material. When the internal pressurization component applies a radial expansion force to the central tube, the central tube can undergo elastic deformation. When the radial expansion force applied to the central tube is removed, the central tube returns to its state before expansion.

[0021] In one embodiment, the external pressurization assembly includes a plurality of second drive members and a plurality of segmented blocks;

[0022] The number of second driving components is the same as the number of segmented blocks. Multiple segmented blocks are arranged circumferentially with the central axis of the central tube as the axis. Each second driving component is fixedly connected to the frame and the corresponding segmented block.

[0023] Each segment has an arc-shaped groove on the side facing the central tube, and the radius of the arc-shaped groove is adapted to the outer diameter of the outer shell.

[0024] Multiple segmented blocks can synchronously close inward or open outward under the drive of the corresponding second driving component. When closing inward, the groove wall of each arc-shaped groove jointly presses against the outer peripheral surface of the shell; when opening outward, the groove wall of each arc-shaped groove disengages from the shell.

[0025] In one embodiment, the frame includes a support plate and a plurality of support rods, which are circumferentially spaced about the central axis of the central tube.

[0026] The support plate is fixedly connected to the external pressure assembly. The first driving component and the support plate are spaced apart along the axial direction of the central tube. One end of the support rod is fixedly connected to the first driving component, and the other end is fixedly connected to the support plate.

[0027] In one embodiment, this application also provides a pressurization method for a cylindrical solid-state battery, applied to the aforementioned pressurization device for a cylindrical solid-state battery, the method comprising:

[0028] The prepared positive electrode sheet, negative electrode sheet and solid electrolyte membrane are sequentially wound around the outer periphery of the central tube to prepare the core.

[0029] A casing is fitted onto the core, and positive electrode busbar welding, negative electrode busbar welding, and perimeter sealing welding are performed sequentially to prepare a cylindrical battery.

[0030] The cylindrical battery is placed in the preset position on the frame. The external and internal pressure components work together to apply pressure to the outer circumference of the core through the pressure device and to apply pressure to the inner circumference of the core through the internal pressure component. This allows the core to adjust the contact state of the core interface under bidirectional compression and reduce the contact resistance of the core interface.

[0031] The cylindrical battery is activated by charging and discharging to generate expansion force on the positive and negative electrode plates;

[0032] After the cylindrical battery is activated by charging and discharging, the internal and external pressurization components are deactivated.

[0033] In one embodiment, after the internal pressurization assembly is removed, a solid rod adapted to the inner diameter of the central tube is inserted into the central tube so that the solid rod can fill the central tube after insertion.

[0034] In one embodiment, this application also provides a cylindrical solid-state battery, which is prepared by the above method, with the central tube placed inside the core and a solid rod inserted inside the central tube, so that the central tube and the solid rod both form part of the cylindrical solid-state battery.

[0035] In the aforementioned pressurizing device for cylindrical solid-state batteries, the core is subjected to bidirectional extrusion by the first and second radial pressures generated by the internal and external pressurizing components. This forces the solid electrolyte membrane to adhere tightly to the positive and negative electrode sheets and maintains a high cross-sectional pressure, thereby effectively reducing the contact resistance at the solid-solid interface, decreasing ion transport resistance, and improving the rate performance of the cylindrical battery. Simultaneously, the bidirectional extrusion avoids problems such as eccentricity, offset, or uneven stress that easily occur when the core is extruded from one side, improving the uniformity and consistency of pressure distribution among the film layers of the core. This ensures uniform overall density and structural stability of the core, thereby improving the cycle stability and lifespan of the cylindrical battery. Thus, by performing bidirectional extrusion on the core of the cylindrical battery, a uniform and stable high pressure is formed between the films, thereby improving the rate performance, cycle stability, and lifespan of the cylindrical battery.

[0036] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this application, nor is it intended to limit the scope of this application. Other features of this application will become readily apparent from the following description. Attached Figure Description

[0037] The above and other objects, features, and advantages of exemplary embodiments of this application will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings. Several embodiments of this application are illustrated in the drawings by way of example and not limitation, in which:

[0038] In the accompanying drawings, the same or corresponding reference numerals indicate the same or corresponding parts.

[0039] Figure 1 A schematic diagram of the pressurizing device and cylindrical battery in an embodiment of this application is shown;

[0040] Figure 2 It shows Figure 1 A schematic diagram of the structure of the central tube, transmission components, and arc-shaped petals;

[0041] Figure 3It shows Figure 2 A cross-sectional view of the central tube, transmission components, and arc-shaped petals along the III-III direction.

[0042] Figure 4 It shows Figure 2 An exploded view of the central tube, transmission components, and arc-shaped petals;

[0043] Figure 5 It shows Figure 1 A schematic diagram of the structure of the central bearing plate and external pressure assembly.

[0044] Explanation of the labels in the diagram:

[0045] In the diagram: 10. Pressurizing device; 11. Frame; 111. Bearing plate; 112. Support rod; 12. Central tube; 13. Internal pressurizing assembly; 131. First driving component; 132. Transmission component; 1321. Central rod; 1322. Connecting rod; 1323. Fixed tube; 1324. Hinge rod; 133. Arc-shaped petal; 14. External pressurizing assembly; 141. Second driving component; 142. Split block; 143. Arc-shaped groove; 20. Cylindrical battery. Detailed Implementation

[0046] To make the objectives, features, and advantages of this application more apparent and understandable, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0047] It should be understood that the various forms of processes shown above can be used to rearrange, add, or delete steps. For example, the steps described in this application can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this application can be achieved, and this is not limited herein.

[0048] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0049] Cylindrical solid-state batteries offer advantages such as high energy density, high safety, and a wide operating range, making them an important development direction for power batteries. Unlike liquid batteries where the electrolyte can spontaneously wet and fill gaps, solid-state batteries have microscopic roughness at the solid-solid interface. If the contact is not tight, it will lead to extremely high interfacial contact resistance, severely hindering the transport of lithium ions and significantly reducing the battery's rate performance and capacity. In addition, during charge-discharge cycles, the electrode materials also undergo periodic volume expansion and contraction (i.e., the breathing effect). If the initial interfacial bonding force is insufficient or the pressure distribution is uneven, it can easily lead to an increase in interfacial resistance, which in turn causes a sharp increase in the battery's internal resistance or even failure, seriously affecting the battery's cycle life.

[0050] In related technologies, the pressure application approach used in pouch cells ensures the adhesion between the film layers of the core by applying radial pressure to one side of the cylindrical battery casing. However, since the core of a solid-state battery requires higher pressure (10MPa) to charge and discharge, applying unidirectional pressure to the outside of the core can easily cause the core to become eccentric or shifted within the cylindrical casing, resulting in insufficient overall interfacial pressure from the outside to the inside of the core and extremely uneven distribution of interfacial pressure.

[0051] Therefore, researchers discovered that in pouch solid-state batteries, by setting a central tube that can generate a preset deformation in the central hole of the pouch battery, and by utilizing the slight deformation capability of the pouch battery shell, the core can be subjected to double compression from the inside and outside, so as to apply higher and more uniform pressure to the core, thereby ensuring the reliability and stability of the solid-solid interface pressure of the solid-state battery core.

[0052] The following embodiments, in conjunction with the accompanying drawings, illustrate this application.

[0053] Combination Figure 1-2 This embodiment provides a pressurizing device 10 for a cylindrical solid-state battery, used to compress the core of a cylindrical battery 20. Specifically, the cylindrical battery 20 is a cylindrical soft-pack solid-state battery, including a core, end caps, and a casing. The pressurizing device 10 includes a frame 11, a central tube 12, an internal pressurizing assembly 13, and an external pressurizing assembly 14. The frame 11 is used to support the cylindrical battery 20, and the central tube 12 serves as a support shaft during the winding process of the cylindrical battery 20 core and is capable of generating a preset radial deformation. The internal pressurizing assembly 13 is connected to the frame 11. 1. It can extend retractably into the central tube 12 to apply radial pressure to the tube wall of the central tube 12, thereby driving the central tube 12 to generate a first radial pressure on the core of the cylindrical battery 20; the external pressurizing component 14 is connected to the frame 11 to apply radial pressure to the outer casing of the cylindrical battery 20, thereby driving the outer casing to apply a second radial pressure on the core; wherein, the internal pressurizing component 13 and the external pressurizing component 14 work together to enable the core to adjust the contact state of the core interface under the bidirectional compression of the first radial pressure and the second radial pressure.

[0054] In the pressurizing device 10 of the cylindrical solid-state battery described above, the first radial pressure and the second radial pressure generated by the internal pressurizing component 13 and the external pressurizing component 14 perform bidirectional extrusion of the core, which can force the solid electrolyte membrane to adhere tightly to the positive and negative electrode sheets and maintain a high cross-sectional pressure, thereby effectively reducing the contact resistance of the solid-solid interface, reducing ion transport resistance, and improving the rate performance of the cylindrical battery 20. At the same time, through bidirectional extrusion, problems such as eccentricity, offset, or uneven force that are prone to occur when the core is extruded on one side can be avoided, improving the uniformity and consistency of pressure distribution between the film layers of the core, ensuring uniform overall density and structural stability of the core, and thus improving the cycle stability and life of the cylindrical battery 20. In this way, by performing bidirectional extrusion on the core of the cylindrical battery 20, the core can form a uniform and stable high pressure between the films, thereby improving the rate performance, cycle stability, and life of the cylindrical battery 20.

[0055] It should be noted that rate performance refers to the battery's ability to output capacity normally and maintain stable operation under high current charging and discharging conditions.

[0056] In some preferred embodiments, the first radial pressure is 5-8 MPa and the second radial pressure is 5-8 MPa. During the extrusion operation, both the internal pressurizing component 13 and the external pressurizing component 14 need to enter the 5-8 MPa range and maintain the pressure for a certain period of time.

[0057] Thus, a pressure of 5-8 MPa is moderate, effectively overcoming the microscopic roughness of the solid-solid interface, allowing the solid electrolyte membrane to fully adhere to the positive and negative electrodes and form a dense contact, significantly reducing interfacial contact resistance, improving lithium-ion transport efficiency, and thus improving the battery's rate performance and capacity utilization; at the same time, it can avoid damage, deformation, or short circuits to the electrode sheets or solid electrolyte membrane caused by excessive pressure, ensuring the integrity and safety of the battery structure; at the same time, by holding the pressure for a certain period of time, the solid electrolyte membrane can be fully embedded into the micropores and pits on the electrode surface under pressure, forming microscopic physical interlocking and mechanical interlocking, making the interfacial contact state fully stable and irreversibly dense, avoiding interface rebound and separation after the pressure is removed, so that the battery can maintain low interfacial impedance and good electrochemical performance in subsequent cycles.

[0058] Combination Figure 1 and Figure 2In some embodiments, the internal pressurization assembly 13 includes a first driving member 131, a transmission member 132, and a plurality of arc-shaped petals 133. Each arc-shaped petal 133 extends axially along the central tube 12, and the plurality of arc-shaped petals 133 are disposed within the central tube 12 and are circumferentially spaced about the central axis of the central tube 12, forming an inner cavity. The transmission member 132 is located within the inner cavity and is connected to the first driving member 131 and each arc-shaped petal 133 in a transmission connection. The first driving member 131 drives the transmission member 132 to move, so that the transmission member 132 drives the plurality of arc-shaped petals 133 to move radially synchronously. When the plurality of arc-shaped petals 133 move radially synchronously, they jointly push against the wall of the central tube 12, causing it to undergo a preset deformation, so that the central tube 12 presses against the inner wall of the winding core with a first radial pressure. Exemplarily, the first driving member 131 can be a linear motor, a telescopic cylinder, or a telescopic hydraulic cylinder.

[0059] Thus, by employing multiple axially extending arc-shaped lobes 133 and moving them synchronously radially, the internally applied expansion force is transformed into uniform surface contact across multiple regions. This ensures that the thrust on the central tube 12 is highly consistent in all circumferential directions, avoiding the risk of the central tube 12 breaking or the inner wall of the core being damaged due to localized stress concentration. Simultaneously, the synchronous movement of the arc-shaped lobes 133 ensures the roundness of the core's inner hole expansion, preventing the inner hole from deforming into an ellipse or polygon. This ensures that the first radial pressure is evenly distributed in the inner circumferential direction of the core, further improving the uniformity of the pressure applied to the inner wall of the core and providing a perfect internal support foundation for the tight bonding of the solid electrolyte membrane and the electrode.

[0060] In some preferred embodiments, since the internal assembly space of the central tube 12 is small, it is difficult to arrange pressure sensors for direct online pressure detection. Therefore, by controlling the output shaft of the first driving member 131 to move to a preset position, the arc-shaped petals 133 are simultaneously opened to the target state. At this time, multiple arc-shaped petals 133 enclose a regular cylindrical space, and at the same time, the pressure applied by the central tube 12 to the inner wall of the core is stably placed within the preset range of 5-8 MPa.

[0061] In this way, the method eliminates the need to install pressure sensors in a confined space, thus avoiding the detection difficulties caused by insufficient internal space. It also enables precise and reliable control of interface pressure through stroke control, ensuring that the pressure applied by the central tube 12 to the inner wall of the core is moderate and uniform.

[0062] In some preferred embodiments, the number of arc-shaped lobes 133 can be 2-4.

[0063] Combination Figure 3 and Figure 4In some optional embodiments, the transmission component 132 includes a central rod 1321 and multiple sets of connecting rods 1322, the number of sets of connecting rods 1322 being the same as the number of arc-shaped petals 133; the central rod 1321 is coaxially arranged with the central tube 12, each set of connecting rods 1322 is inclined relative to the central rod 1321, and one end of each set of connecting rods 1322 is close to the first driving component 131 and rotatably connected to the central rod 1321, and the other end is away from the first driving component 131 and rotatably connected to a corresponding arc-shaped petal 133, the first driving component 131 being connected to one end of the central rod 1321.

[0064] During operation, the first driving component 131 drives the central rod 1321 to move linearly along the axial direction. The lower end of the arc-shaped petal 133 first abuts against the frame 11. The bearing plate 111 of the frame 11 axially limits the arc-shaped petal 133 so that the arc-shaped petal 133 can only move radially. At this time, there is still a certain distance between the lower end of the central rod 1321 and the bearing plate 111 of the frame 11. The central rod 1321 drives multiple sets of connecting rods 1322 to swing synchronously, converting the axial driving force into a radially outward thrust, thereby pushing each set of arc-shaped petals 133 to expand outward synchronously along the radial direction. When the first driving component 131 retracts, the central rod 1321 drives the connecting rods 1322 to swing in the opposite direction, and the arc-shaped petal 133 synchronously contracts and resets radially.

[0065] Thus, by setting the central rod 1321 coaxially with the central tube 12, it can be ensured that the force is centered, without eccentric load or lateral offset during transmission, and that the driving angle and driving stroke of each set of connecting rods 1322 are consistent. This enables multiple arc-shaped petals 133 to move radially synchronously, with the same amplitude, and uniformly, avoiding uneven expansion of the central tube 12, local stress concentration, or eccentric deformation of the core caused by asynchronous movement. At the same time, the transmission form with the connecting rods 1322 arranged at an angle is compact, direct, and efficient, and can be adapted to the narrow space inside the central tube 12. It achieves reliable driving without occupying too much installation space. The overall structure is simple, the action is stable, and the response is precise, providing reliable structural support for the precise control of the opening size and internal pressure of the arc-shaped petals 133.

[0066] Combination Figure 3 and Figure 4In some embodiments, the transmission component 132 further includes a fixed tube 1323 and multiple sets of hinge rods 1324, the number of sets of hinge rods 1324 being the same as the number of arc-shaped petals 133; one end of each set of hinge rods 1324 is rotatably connected to the fixed tube 1323, and the other end is rotatably connected to the arc-shaped petal 133, and the hinge rods 1324 and the connecting rods 1322 are symmetrically arranged about a radial plane of the arc-shaped petal 133; the fixed tube 1323 is slidably sleeved on the central rod 1321, and a stop (not shown) is provided at one end of the fixed tube 1323 near the first driving component 131, the stop protruding from the fixed tube 1323 in the radial direction of the fixed tube 1323, and is used to abut against the external pressure assembly 14 or the frame 11.

[0067] At the start of operation, the fixed tube 1323 is axially positioned and stationary by a stop against the external pressure assembly 14 or the frame 11, while providing guiding support for the central rod 1321 fitted inside. After the first driving component 131 is activated, it drives the central rod 1321 to move axially, causing multiple sets of connecting rods 1322 corresponding to the arc-shaped petals 133 to swing synchronously, converting the axial driving force into radial thrust, and pushing each arc-shaped petal 133 to expand radially synchronously. At the same time, the connecting rods 1322 corresponding to the arc-shaped petals 133... The hinge rod 1324 swings synchronously with it. Because it is symmetrically arranged with the connecting rod 1322, it forms a linkage support with the fixed tube 1323 as the hinge base, thereby forming different linkage support points in the axial direction of the arc-shaped petal 133, making the compression of the arc-shaped petal 133 on the central tube 12 more uniform. After the operation is completed, the first driving member 131 drives the central rod 1321 to move in the opposite direction, driving the connecting rod 1322, the hinge rod 1324 and the arc-shaped petal 133 to reset, and the internal pressure assembly 13 returns to its initial state.

[0068] Thus, the center rod 1321 is guided by the fixed tube 1323. After the center rod 1321 is inserted into the fixed tube 1323, the deformation resistance of the fixed tube 1323 is improved, thereby preventing the center rod 1321 and the fixed tube 1323 from bending or shifting when subjected to the forces of the connecting rod 1322 and the hinge rod 1324 respectively. At the same time, the connecting rod 1322 and the hinge rod 1324 are symmetrically arranged to form a double connecting rod 1322 support. Combined with the one-to-one correspondence between the connecting rod 1322 and the arc-shaped petals 133, the driving force can be uniformly converted into radial expansion force, realizing the synchronous and stable expansion of the arc-shaped petals 133, avoiding uneven force and roundness deformation of the center tube 12. The transmission components are compactly laid out, adapted to the narrow space of the center tube 12, and do not require complex additional components.

[0069] In some preferred embodiments, there are multiple hinge rods 1324 in each group, which are spaced apart along the axial direction of the fixed tube 1323. Multiple hinge rods 1324 in each group are parallel to and coplanar with the hinge axis of the fixed tube 1323, and are also parallel to and coplanar with the hinge axis of the arc-shaped petal 133. Similarly, there are multiple connecting rods 1322 in each group, which are spaced apart along the axial direction of the central rod 1321. Multiple connecting rods 1322 in each group are parallel to and coplanar with the hinge axis of the central rod 1321, and are also parallel to and coplanar with the hinge axis of the arc-shaped petal 133.

[0070] Combination Figure 4 Furthermore, the hinge axes of the connecting rods 1322 connected to each arc-shaped petal 133 at the same height are located on the same plane, and the included angle between any two connecting rods 1322 is the same. This layout allows the reverse forces generated by each connecting rod 1322 on the central rod 1321 to cancel each other out, effectively weakening the lateral stress on the central rod 1321 and further reducing the risk of bending and deformation of the central rod 1321. This ensures that the radial pressure applied by each arc-shaped petal 133 to the central tube 12 is uniform and stable, providing a more reliable guarantee for the uniform compaction of the core interface.

[0071] Combination Figure 4 Furthermore, the hinge axes of the hinge rods 1324 connected to each arc-shaped petal 133 at the same height are located on the same plane, and the included angle between any two hinge rods 1324 is the same. This layout allows the reverse forces generated by each hinge rod 1324 on the central rod 1321 to cancel each other out, effectively reducing the lateral stress on the central rod 1321 and further reducing the risk of bending and deformation of the fixed tube 1323. This ensures that the radial pressure applied by each arc-shaped petal 133 to the central tube 12 is uniform and stable, providing a more reliable guarantee for the uniform compaction of the core interface.

[0072] In some alternative embodiments, the central tube 12 is made of a plastic metal material that allows the central tube 12 to undergo plastic deformation when the internal pressure assembly 13 applies a radial expansion force to the central tube 12, and retains the expanded shape when the radial expansion force applied to the central tube 12 is removed; for example, the plastic metal material may be an aluminum alloy.

[0073] Thus, when the central tube 12 is made of a plastic metal material, it can undergo plastic deformation under the radial expansion force of the internal pressure component 13. After the external force is removed, it can still maintain the expanded shape, thereby providing continuous and stable internal support for the core, ensuring that the core structure is stable after pressure molding and that the interface does not spring back, thus improving the battery molding accuracy and structural reliability.

[0074] In some alternative embodiments, the central tube 12 is made of an elastic material that allows it to elastically deform when the internal pressurizing assembly 13 applies a radial expansion force to it, and to return to its pre-expansion state when the radial expansion force is removed. Exemplarily, the elastic material may be spring steel.

[0075] Thus, when the central tube 12 is made of elastic material, it can apply dynamic adaptive pressure compensation to the inner wall of the core by means of the elastic rebound force of the material itself. It can adapt to the volume expansion and contraction (volume breathing effect) generated by the battery during the charge and discharge cycle in real time, and always maintain the tight fit between the solid electrolyte membrane and the electrode interface. It can effectively avoid poor interface contact, increased internal resistance or performance degradation caused by volume changes, and significantly improve the cycle stability and service life of the battery.

[0076] Combination Figure 5 In some embodiments, the external pressurization assembly 14 includes a plurality of second driving members 141 and a plurality of segmented blocks 142; the number of second driving members 141 is the same as the number of segmented blocks 142, and the plurality of segmented blocks 142 are circumferentially spaced about the central axis of the central tube 12. Each second driving member 141 is fixedly connected to the frame 11 and the corresponding segmented block 142; each segmented block 142 has an arc-shaped groove 143 on the side facing the central tube 12, and the radius of the arc-shaped groove 143 is adapted to the outer diameter of the outer shell; the plurality of segmented blocks 142 can synchronously close inward or open outward under the drive of the corresponding second driving member 141. When closing inward, the groove wall of each arc-shaped groove 143 jointly presses against the outer peripheral surface of the outer shell; when opening outward, the groove wall of each arc-shaped groove 143 disengages from the outer shell. Exemplarily, the second driving member 141 can be a linear motor, a telescopic cylinder, or a telescopic hydraulic cylinder.

[0077] Thus, the external pressurization component 14 adopts a structure in which multiple second driving components 141 and multiple segmented blocks 142 are matched one-to-one. The multiple segmented blocks 142 are arranged circumferentially around the central axis of the central tube 12, and can synchronously close inward or open outward under the drive of each second driving component 141, so as to ensure that a uniform and synchronous radial extrusion force is applied to the outer periphery of the shell. Each segmented block 142 is provided with an arc-shaped groove 143 adapted to the outer diameter of the shell on the side facing the central tube 12. The arc-shaped groove 143 can form a surface contact fit with the outer peripheral surface of the shell, effectively increasing the pressure application area and avoiding local stress concentration that causes indentation or deformation to the shell.

[0078] In some preferred embodiments, the number of the second drive element 141 and the number of the segmented blocks 142 are the same, and both are 2-4.

[0079] Combination Figure 1In some embodiments, the frame 11 includes a support plate 111 and a plurality of support rods 112, which are circumferentially spaced about the central axis of the central tube 12. The support plate 111 is fixedly connected to the external pressure assembly 14, and the first drive member 131 is spaced apart from the support plate 111 along the axial direction of the central tube 12. One end of the support rod 112 is fixedly connected to the first drive member 131, and the other end is fixedly connected to the support plate 111.

[0080] Thus, the bearing plate 111 is fixedly connected to the external pressurizing component 14, providing a stable installation base for the external pressurizing component 14; the first driving component 131 and the bearing plate 111 are spaced apart along the axial direction of the central tube 12 and are rigidly connected by the support rod 112, which can effectively ensure the relative positional accuracy and coaxiality between the first driving component 131 and the external pressurizing component 14, and avoid misalignment or shaking during pressurization.

[0081] In some preferred embodiments, each segment block 142 is slidably connected to the support plate 111, and the sliding direction is the radial direction of the central tube 12, so as to improve the moving accuracy and stability of the segment block 142 and avoid the segment block 142 from deflecting due to the squeezing of the cylindrical battery 20.

[0082] Specifically, there are 3-5 support rods 112 to provide multi-point stable support for the first drive member 131.

[0083] In some embodiments, this application also provides a pressurization method for a cylindrical solid-state battery, applied to the pressurization device 10 for the cylindrical battery described above, the method comprising:

[0084] Step S1: The prepared positive electrode sheet, negative electrode sheet and solid electrolyte membrane are sequentially wound around the outer periphery of the central tube 12 to prepare the core;

[0085] Step S2: The outer shell is fitted onto the core, and the positive electrode busbar welding, negative electrode busbar welding and sealing perimeter welding are performed in sequence to prepare the cylindrical battery 20;

[0086] Step S3: Place the cylindrical battery 20 in the preset position on the frame 11. The external pressure component 14 and the internal pressure component 13 work together to apply pressure to the outer peripheral surface of the core through the pressure device 10 and to apply pressure to the inner peripheral surface of the core through the internal pressure component 13, so that the core can adjust the contact state of the core interface under bidirectional compression and reduce the contact resistance of the core interface.

[0087] Step S4: Charge and discharge the cylindrical battery 20 to activate it, so that the positive and negative electrode plates generate expansion force;

[0088] Step S5: After the cylindrical battery 20 is activated by charging and discharging, the internal pressurization component 13 and the external pressurization component 14 are deactivated. Specifically, the cylindrical battery is a cylindrical solid-state battery.

[0089] Thus, in steps S1 to S2, the central tube 12 is used as a spool, and the conventional process flow of core preparation and battery packaging is followed to ensure the basic forming quality of the cylindrical battery 20, laying a good foundation for subsequent pressurization operations. In step S3, the external pressurization component 14 and the internal pressurization component 13 work together to achieve bidirectional synchronous extrusion of the outer and inner circumferential surfaces of the core. Compared with single-direction pressurization, the core can be subjected to uniform radial force, effectively adjusting the interface contact state between the positive electrode sheet, negative electrode sheet and solid electrolyte membrane inside the core, fully compacting the solid-solid interface, significantly reducing interface contact resistance, reducing interface polarization during battery charging and discharging, and providing a guarantee for improving battery rate performance and cycle life. Meanwhile, bidirectional pressurization can prevent problems such as eccentricity and deformation of the core, ensuring the roundness and dimensional stability of the core structure. The charge and discharge activation step S4 causes the positive and negative electrode sheets to generate natural expansion force. This expansion force works synergistically with the force of bidirectional pressurization to further promote tighter bonding of the core interface, consolidate the pressurization effect, and prevent the interface from loosening or peeling during subsequent use. At the same time, it activates the battery active materials, ensuring that the battery can quickly reach stable electrochemical performance. Step S5 removes the internal and external pressurization components after the cylindrical battery 20 is activated. This avoids damage to the battery casing and core caused by excessive pressurization, and allows the battery to maintain a stable interface contact state under natural conditions, adapting to the usage requirements under different working conditions.

[0090] In some embodiments, step S6: after removing the internal pressurization assembly 13, a solid rod adapted to the inner diameter of the central tube 12 is inserted into the central tube 12 so that the solid rod can fill the central tube 12 after insertion.

[0091] Thus, after the internal pressurization assembly 13 is removed, a solid rod that matches the inner diameter of the central tube 12 is inserted into the central tube 12. The solid rod can completely fill the internal space of the central tube 12, providing stable radial support for the central tube 12. This prevents the central tube 12 from shrinking or deforming due to the loss of support from the internal pressurization assembly 13, thereby ensuring that the inner circumference of the core always maintains a stable support state, consolidating the effect of bidirectional pressurization and charge / discharge activation, preventing the core interface from loosening due to deformation of the central tube 12, and further reducing the interface contact resistance.

[0092] In some embodiments, this application also provides a cylindrical solid-state battery, which is prepared by the above method, wherein the central tube 12 is placed inside the core and a solid rod is inserted into the central tube 12, so that the central tube 12 and the solid rod both form part of the cylindrical solid-state battery.

[0093] In this way, there is no need to remove the central tube 12 and the solid rod from the core, simplifying the production process, improving production efficiency, and avoiding material waste. At the same time, the central tube 12 and the solid rod can provide stable radial support for the core for a long time, continuously consolidating the tight contact state of the core interface, avoiding problems such as core loosening and poor interface contact under the volume breathing effect of long-term charge and discharge cycles, further reducing interface contact resistance and reducing interface polarization. In addition, the retained central tube 12 and solid rod can also enhance the overall structural rigidity of the battery, prevent the battery from deforming when subjected to external impact, improve the structural reliability and service life of the battery, and the two have good compatibility with the core and shell, without affecting the electrochemical performance of the battery, achieving a dual improvement in production efficiency and overall battery performance.

[0094] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A pressurizing device of a cylindrical solid-state battery for pressing a jelly-roll of a cylindrical battery; characterized by, The pressurizing device includes a frame, a central tube, an internal pressurizing assembly, and an external pressurizing assembly. The frame supports the cylindrical battery, and the central tube serves as a support shaft for the winding process of the cylindrical battery core and is capable of generating a preset radial deformation. The internal pressurizing assembly is connected to the frame and extends retractably into the central tube, applying radial pressure to the tube wall of the central tube to drive the central tube to generate a first radial pressure on the core of the cylindrical battery. The external pressurizing assembly is connected to the frame and applies radial pressure to the outer casing of the cylindrical battery, driving the outer casing to apply a second radial pressure on the core. The internal and external pressurizing assemblies work together to allow the core to adjust the contact state of the core interface under the bidirectional compression of the first and second radial pressures. The internal pressurization assembly includes a first driving component, a transmission component, and multiple arc-shaped petals; each arc-shaped petal extends along the axial direction of the central tube, and the multiple arc-shaped petals are disposed inside the central tube and are circumferentially spaced around the central axis of the central tube, and the multiple arc-shaped petals surround to form an inner cavity; the transmission component is located in the inner cavity and is respectively connected to the first driving component and each arc-shaped petal; The first driving member is used to drive the transmission member to move, so that the transmission member drives the multiple arc-shaped petals to move radially synchronously; when the multiple arc-shaped petals move radially synchronously, they jointly push against the wall of the central tube to cause a preset deformation, so that the central tube presses against the inner wall of the core with a first radial pressure. The transmission component includes a central rod and multiple sets of connecting rods, the number of sets of connecting rods being the same as the number of arc-shaped petals; the central rod is coaxially arranged with the central tube, each set of connecting rods is inclined relative to the central rod, and one end of each set of connecting rods is close to the first driving component and rotatably connected to the central rod, while the other end is away from the first driving component and rotatably connected to a corresponding arc-shaped petal, and the first driving component is connected to one end of the central rod.

2. The pressurizing device of a cylindrical solid-state battery according to claim 1, characterized by, The transmission component also includes a fixed tube and multiple sets of hinge rods, the number of which is the same as the number of the arc-shaped petals; One end of each set of hinge rods is rotatably connected to the fixed tube, and the other end is rotatably connected to the arc-shaped petal. The hinge rods and the connecting rods are symmetrically arranged about a radial plane of the arc-shaped petal. The fixed tube is slidably sleeved on the central rod. A stop is provided at one end of the fixed tube near the first driving member. The stop protrudes from the fixed tube in the radial direction and is used to abut against the external pressure assembly or the frame.

3. The pressurizing device for the cylindrical solid-state battery according to claim 1, characterized in that, The central tube is made of a ductile metal material. When the internal pressurizing assembly applies a radial expansion force to the central tube, the central tube can undergo plastic deformation. When the radial expansion force is removed, the central tube retains its expanded shape; or... The central tube is made of an elastic material. When the internal pressurization assembly applies a radial expansion force to the central tube, the central tube can undergo elastic deformation. When the radial expansion force applied to the central tube is removed, the central tube returns to its state before expansion.

4. The pressurizing device for a cylindrical solid-state battery according to claim 1, characterized in that, The external pressurization assembly includes multiple second driving elements and multiple segmented blocks; The number of the second driving components is the same as the number of the segmented blocks. The multiple segmented blocks are arranged circumferentially with the central axis of the central tube as the axis. Each second driving component is fixedly connected to the frame and the corresponding segmented block. Each of the segmented blocks has an arc-shaped groove on the side facing the central tube, and the radius of the arc-shaped groove is adapted to the outer diameter of the outer shell; Multiple of the segmented blocks can synchronously close inward or open outward under the drive of the corresponding second driving member. When closing inward, the groove wall of each arc-shaped groove jointly presses against the outer peripheral surface of the outer shell. When it opens outward, the wall of each of the arcuate grooves disengages from the outer shell.

5. The pressurizing device for a cylindrical solid-state battery according to claim 1, characterized in that, The frame includes a bearing plate and multiple support rods, which are circumferentially spaced about the central axis of the central tube. The support plate is fixedly connected to the external pressurization component. The first driving member and the support plate are spaced apart along the axial direction of the central tube. One end of the support rod is fixedly connected to the first driving member, and the other end is fixedly connected to the support plate.

6. A method for pressurizing a cylindrical solid-state battery, characterized in that, The pressurization device applied to the cylindrical solid-state battery as described in any one of claims 1-5, the method comprising: The prepared positive electrode sheet, negative electrode sheet, and solid electrolyte membrane are sequentially wound around the outer periphery of the central tube to prepare a core. The core is fitted with a shell, and positive electrode busbar welding, negative electrode busbar welding and perimeter sealing welding are performed in sequence to prepare a cylindrical battery. The cylindrical battery is placed in a preset position on the frame. The external pressurizing component and the internal pressurizing component work together to apply pressure to the outer peripheral surface of the core through the pressurizing device and to apply pressure to the inner peripheral surface of the core through the internal pressurizing component, so that the core can adjust the contact state of the core interface under bidirectional compression and reduce the contact resistance of the core interface. The cylindrical battery is activated by charging and discharging to generate expansion force in the positive and negative electrode plates. After the cylindrical battery is activated by charging and discharging, the internal pressurization assembly and the external pressurization assembly are deactivated.

7. The pressurization method for a cylindrical solid-state battery according to claim 6, characterized in that, After the internal pressurization assembly is removed, a solid rod that matches the inner diameter of the central tube is inserted into the central tube so that the solid rod can fill the central tube after insertion.

8. A cylindrical solid-state battery, characterized in that, The cylindrical solid-state battery is prepared by the method described in any one of claims 6-7, wherein the central tube is placed inside the winding core, and a solid rod is inserted into the central tube, so that the central tube and the solid rod both form part of the cylindrical solid-state battery.

Images