A method and equipment for pressing all-solid-state battery cells

Abstract

This invention provides a method and equipment for pressing all-solid-state battery cells, belonging to the field of solid-state battery manufacturing technology. The method includes: a pressurization stage: applying pressure to the cell stack to a reference pressure; a pre-pressurization stage: maintaining a constant temperature and applying a first pulsed pressurization to the cell stack based on the reference pressure; a main pressurization stage: maintaining a constant temperature and applying a second pulsed pressurization to the cell stack based on the reference pressure to achieve close contact between the positive electrode, solid electrolyte membrane, and negative electrode of the cell stack; a holding pressure stage: maintaining a constant temperature and applying a third pulsed pressurization to the cell stack based on the reference pressure; and a depressurization stage: maintaining a constant temperature and linearly reducing the pressure to 0 MPa. This method avoids damage to the electrolyte and electrode materials while achieving uniform and close contact at the interface, improving the electrochemical performance and manufacturing yield of the cell.

Description

Technical Field

[0001] This invention belongs to the field of solid-state battery manufacturing technology, and specifically relates to a method and equipment for pressing all-solid-state battery cells. Background Technology

[0002] Sulfide solid-state batteries, with their advantages such as high ionic conductivity and excellent mechanical properties, have become an important development direction for next-generation high-energy-density energy storage devices. In the manufacturing process of sulfide solid-state battery cells, the stacking or hot-pressing process is a crucial step that determines the cell's performance—this process requires achieving tight contact between the electrolyte sheet and the positive and negative electrode sheets to reduce solid-solid interface impedance and ensure ion transport efficiency.

[0003] In existing technologies, cell compaction often employs a continuous pressure mode (such as constant hydraulic pressure or mechanical pressurization), but this method has the following technical drawbacks:

[0004] 1. High risk of material damage: Sulfide electrolytes (such as Li6PS5Cl, Li 10 GeP2S 12 The electrolyte has high mechanical brittleness, and continuous high pressure can easily cause cracks or breakage of the electrolyte sheet, damaging the ion transport channels. At the same time, continuous pressure may cause the active material of the electrode sheet to fall off or the current collector to deform, reducing the cycle stability of the cell.

[0005] 2. Poor interface contact uniformity: Continuous pressure can cause excessive compression in local areas of the stacked structure (such as edges or protrusions), and the local areas cannot make sufficient contact due to the remaining gaps, resulting in uneven interface impedance distribution, which affects the rate performance and life of the cell.

[0006] 3. Poor process adaptability: When sulfide electrolyte sheets of different thicknesses are combined with electrode sheets of different compaction densities, the continuous pressure is difficult to match the diverse interface contact requirements, which can easily lead to problems such as "overpressure damage" or "underpressure poor contact".

[0007] Therefore, there is an urgent need to develop a cell compaction technology that can precisely control pressure output and take into account both interface tightness and material integrity, in order to solve the shortcomings of the existing continuous pressure process and promote the industrial application of sulfide solid-state batteries. Summary of the Invention

[0008] To address the issues of material damage and poor interface contact uniformity in existing cell compaction processes, this invention provides a method for compacting all-solid-state battery cells. This method avoids damage to the electrolyte and electrode materials while achieving uniform and tight interface contact, thereby improving the electrochemical performance and manufacturing yield of the cell.

[0009] The present invention also provides an all-solid-state battery cell pressing device.

[0010] This invention is achieved through the following technical solution:

[0011] This invention provides a method for pressing all-solid-state battery cells, the pressing method comprising:

[0012] S1. Pressurization stage: The battery cell stack is placed in a pressing device and pressure is applied to the battery cell stack. The pressure is linearly increased to the reference pressure to achieve initial contact between the positive electrode, solid electrolyte membrane and negative electrode of the battery cell stack.

[0013] S2. Pre-pressurization stage: After the pressurization stage is completed, the temperature is kept constant, and the cell stack is subjected to the first pulse pressurization on the basis of the reference pressure to initially eliminate the voids in the cell stack;

[0014] S3. Main pressure stage: After the pre-pressure stage is completed, the temperature is kept constant, and the cell stack is subjected to a second pulse pressurization on the basis of the reference pressure to achieve close contact between the positive electrode, solid electrolyte membrane and negative electrode of the cell stack;

[0015] S4. Pressure Holding Stage: After the main pressure stage is completed, the temperature is kept constant, and the cell stack is subjected to a third pulse pressurization on the basis of the reference pressure to stabilize the interface contact state of the cell stack.

[0016] S5. Pressure relief stage: After the pressure holding stage is completed, the temperature is kept constant and the pressure is linearly reduced to 0 MPa;

[0017] After the pressure relief phase is completed, repeat steps S1 to S5 until the interface resistance is ≤100 Ω·cm. 2 To obtain finished battery cells.

[0018] Furthermore, the pressurization stage specifically includes: placing the battery cell stack in a pressing device, applying pressure to the battery cell stack at 40-60 ℃, linearly increasing the pressure to a reference pressure of 100-300 MPa, and the linear pressurization time of 2-5 min, so as to achieve initial contact between the positive electrode, solid electrolyte membrane and negative electrode of the battery cell stack;

[0019] The solid electrolyte membrane includes any one of sulfide solid electrolyte membrane, oxide solid electrolyte membrane, polymer solid electrolyte membrane, halide solid electrolyte membrane and composite electrolyte solid electrolyte membrane.

[0020] Furthermore, the pre-compression stage specifically includes:

[0021] After the pressurization stage is completed, the temperature is kept constant, and the cell stack is subjected to the first pulse pressurization based on the reference pressure. The pressure amplitude is ± (5~15) MPa, the frequency is 0.1~1 Hz, the duty cycle is 30-70%, and the duration is 1~3 min, so as to initially eliminate the voids in the cell stack.

[0022] Furthermore, the main pressure stage specifically includes:

[0023] After the pre-pressurization stage is completed, the temperature is kept constant, and the cell stack is subjected to a second pulse pressurization based on the reference pressure. The pressure amplitude is ± (20~40) MPa, the frequency is 0.5~10 Hz, the duty cycle is 30-70%, and the duration is 3~8 min, so as to achieve close contact between the positive electrode, solid electrolyte membrane and negative electrode of the cell stack.

[0024] Furthermore, the pressure holding stage specifically includes:

[0025] After the main pressure stage is completed, the temperature is kept constant, and the cell stack is subjected to a third pulse pressurization on the basis of the reference pressure. The pressure amplitude is ± (15~25) MPa, the frequency is 0.1~2 Hz, the duty cycle is 30-70%, and the duration is 1~3 min, so as to stabilize the interface contact state of the cell stack.

[0026] Furthermore, the depressurization stage specifically includes:

[0027] After the pressure holding phase ends, the temperature remains constant, and the pressure decreases linearly from the reference pressure to 0 MPa, with the pressure relief lasting for 2-5 minutes.

[0028] After the pressure relief phase is completed, repeat steps S1 to S5 until the interface resistance is ≤100 Ω·cm. 2 To obtain finished battery cells, specifically including:

[0029] After the depressurization stage is completed, steps S1 to S5 are repeated ≥0 times. Each time this is repeated, the pressure amplitude of the main pressure stage is increased by 0.5-2 MPa until the measured interfacial impedance is ≤100 Ω·cm. 2 To obtain finished battery cells.

[0030] Based on the same inventive concept, this invention provides an application of a method for pressing all-solid-state battery cells in the preparation of sulfide solid-state batteries, oxide solid-state batteries, polymer solid-state batteries, halide solid-state batteries, or composite electrolyte solid-state batteries.

[0031] Based on the same inventive concept, the present invention also provides an all-solid-state battery cell pressing device, the pressing device including a pressure generating unit, a pressure control unit, a positioning fixture unit and a temperature auxiliary unit;

[0032] The pressure generating unit includes a drive system and an output end. The drive system includes a servo hydraulic system or a piezoelectric drive system, and the drive system drives the output end to move up and down.

[0033] The positioning fixture unit includes an upper pressure plate, a lower pressure plate, and a limiting groove. The limiting groove is disposed in the middle of the lower pressure plate, and the upper pressure plate is connected to the output end of the pressure generating unit.

[0034] The temperature auxiliary unit includes a temperature control module and a heating module. The temperature control module includes a temperature sensor and a temperature controller. The temperature sensor is disposed on the surface of the upper pressure plate and the lower pressure plate. The heating module is integrated inside the upper pressure plate and the lower pressure plate. The temperature control module controls the temperature of the upper pressure plate and the lower pressure plate through the heating module.

[0035] Furthermore, the pressure control unit includes a pressure sensor and a programmable controller;

[0036] The pressure sensor is located at the output end of the upper pressure plate, the lower pressure plate, or the pressure generating unit to monitor the pressure applied to the cell stack in real time.

[0037] The programmable controller is connected to the pressure sensor and the drive system, and controls the operation of the drive system based on the data from the pressure sensor. Furthermore, the heating module includes a heating rod or an infrared heating module.

[0038] One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

[0039] 1. The present invention discloses a method for pressing all-solid-state battery cells. This method replaces traditional continuous pressure with pulsed pressure and combines it with temperature control. While avoiding damage to the electrolyte and electrode materials, it achieves uniform and tight contact at the interface, thereby improving the electrochemical performance and manufacturing yield of the cell.

[0040] 2. The present invention provides an all-solid-state battery cell pressing device. The pressure generating unit of the device is used to output pressure to the battery cell. The pressure generating unit adopts a servo hydraulic system or a piezoelectric drive system and can output periodic pulse pressure. The pressure control unit is used to control the output pressure, frequency and action time of the pressure generating unit. The temperature auxiliary unit is used to control the cell temperature to avoid the electrolyte brittleness from increasing at low temperatures. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a schematic diagram of the all-solid-state battery cell pressing equipment of the present invention.

[0043] Figure 2 The diagram shows the pulse pressure waveforms generated at different stages by the all-solid-state battery cell pressing equipment of this invention.

[0044] Figure 3 This is a comparison diagram of the electrochemical impedance of Example 2 and Comparative Example 1 of the present invention.

[0045] Figure 4 This is a comparison chart of the battery cycle performance of Example 2 and Comparative Example 1 of the present invention.

[0046] Reference numerals: 1-PLC controller, 2-servo hydraulic system or piezoelectric drive system, 21-output end, 3-upper pressure plate, 4-lower pressure plate, 41-limit groove, 5-temperature controller. Detailed Implementation

[0047] The present invention will be described in detail below with reference to specific embodiments and examples, thereby making the advantages and various effects of the present invention more clearly apparent. Those skilled in the art should understand that these specific embodiments and examples are for illustrative purposes only and are not intended to limit the present invention.

[0048] Throughout this specification, unless otherwise specified, the terminology used herein should be understood as having the meaning commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In the event of any conflict, this specification shall prevail.

[0049] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0050] The technical principle of this invention is as follows:

[0051] This invention provides a method for pressing all-solid-state battery cells, the pressing method comprising:

[0052] S1. Pressurization stage: The battery cell stack is placed in a pressing device and pressure is applied to the battery cell stack. The pressure is linearly increased to the reference pressure to achieve initial contact between the positive electrode, solid electrolyte membrane and negative electrode of the battery cell stack.

[0053] S2. Pre-pressurization stage: After the pressurization stage is completed, the temperature is kept constant, and the cell stack is subjected to the first pulse pressurization on the basis of the reference pressure to initially eliminate the voids in the cell stack;

[0054] S3. Main pressure stage: After the pre-pressure stage is completed, the temperature is kept constant, and the cell stack is subjected to a second pulse pressurization on the basis of the reference pressure to achieve close contact between the positive electrode, solid electrolyte membrane and negative electrode of the cell stack;

[0055] S4. Pressure Holding Stage: After the main pressure stage is completed, the temperature is kept constant, and the cell stack is subjected to a third pulse pressurization on the basis of the reference pressure to stabilize the interface contact state of the cell stack.

[0056] S5. Pressure relief stage: After the pressure holding stage is completed, the temperature is kept constant and the pressure is linearly reduced to 0 MPa;

[0057] After the pressure relief phase is completed, repeat steps S1 to S5 until the interface resistance is ≤100 Ω·cm. 2 To obtain finished battery cells.

[0058] Furthermore, the pressurization stage specifically includes: placing the battery cell stack in a pressing device, applying pressure to the battery cell stack at 40-60 ℃, linearly increasing the pressure to a reference pressure of 100-300 MPa, and the linear pressurization time of 2-5 min, so as to achieve initial contact between the positive electrode, solid electrolyte membrane and negative electrode of the battery cell stack.

[0059] In this invention, a reference pressure of 100-300 MPa is applied to the battery cell stack for a linear pressurization time of 2-5 minutes to enable initial contact between the electrodes. If the reference pressure is too high, it can easily lead to electrolyte cracking and electrode active material shedding. If the pressure is too low, the interface contact will be poor and the impedance will increase.

[0060] Furthermore, the pre-compression stage specifically includes:

[0061] After the pressurization stage is completed, the temperature is kept constant, and the cell stack is subjected to the first pulse pressurization based on the reference pressure. The pressure amplitude is ± (5~15) MPa, the frequency is 0.1~1 Hz, the duty cycle is 30-70%, and the duration is 1~3 min, so as to initially eliminate the voids in the cell stack.

[0062] In this invention, the purpose of applying the first pulsed pressure to the battery cell stack based on the reference pressure is to initially eliminate the stack gaps and avoid initial high-pressure damage. If the pressure amplitude and frequency are too low, the gaps cannot be eliminated, and if they are too high, the compaction may occur too early, resulting in less room for subsequent adjustment.

[0063] Furthermore, the main pressure stage specifically includes:

[0064] After the pre-pressurization stage is completed, the temperature is kept constant, and the cell stack is subjected to a second pulse pressurization based on the reference pressure. The pressure amplitude is ± (20~40) MPa, the frequency is 0.5~10 Hz, the duty cycle is 30-70%, and the duration is 3~8 min, so as to achieve close contact between the positive electrode, solid electrolyte membrane and negative electrode of the cell stack.

[0065] In this invention, the pressure amplitude of the second pulse pressurization is increased to ±(20~40)MPa, which is beneficial to further compact the layers and achieve close contact. The frequency is increased to 0.5~10 Hz, which can improve the compaction efficiency. If the pressure amplitude and frequency are too low, the compaction efficiency will be low, and if they are too high, it may cause material fatigue.

[0066] Furthermore, the pressure holding stage specifically includes:

[0067] After the main pressure stage is completed, the temperature is kept constant, and the cell stack is subjected to a third pulse pressurization on the basis of the reference pressure. The pressure amplitude is ± (15~25) MPa, the frequency is 0.1~2 Hz, the duty cycle is 30-70%, and the duration is 1~3 min, so as to stabilize the interface contact state of the cell stack.

[0068] In this invention, the pressure amplitude of the third pulse pressurization is reduced to ±(15~25) MPa, and the frequency is reduced to 0.1~2Hz. Appropriately reducing the pressure and frequency for pressure holding is beneficial to the uniform distribution and relaxation of stress at the interface, making the contact state more stable, 'locking in' a good interface, and at the same time avoiding material creep or damage caused by continuous high stress. Appropriately reducing the amplitude and frequency helps to stabilize the interface and avoid overstress.

[0069] Furthermore, the depressurization stage specifically includes:

[0070] After the pressure holding phase ends, the temperature is kept constant, and the pressure is linearly reduced from the reference pressure to 0 MPa, with the pressure relief lasting for 2-5 minutes.

[0071] In this invention, the advantage of linearly reducing the pressure to 0 MPa is that it relieves external pressure;

[0072] After the pressure relief phase is completed, repeat steps S1 to S5 until the interface resistance is ≤100 Ω·cm.2 To obtain finished battery cells, specifically including:

[0073] After the depressurization stage is completed, steps S1 to S5 are repeated ≥0 times. Each time this is repeated, the pressure amplitude of the main pressure stage is increased by 0.5-2 MPa until the measured interfacial impedance is ≤100 Ω·cm. 2 To obtain finished battery cells.

[0074] In this invention, the temperature of the entire pressing process is controlled at 40-60 ℃, which can help improve the interfacial contact performance of the sulfide electrolyte sheet and avoid the exacerbation of electrolyte brittleness at low temperatures.

[0075] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0076] The following will provide a detailed description of the all-solid-state battery cell pressing method and pressing equipment of the present invention, in conjunction with embodiments and experimental data.

[0077] Example 1

[0078] This embodiment provides an all-solid-state battery cell pressing device, such as... Figure 1 As shown, the pressing device includes a pressure generating unit, a pressure control unit, a positioning fixture unit, and a temperature auxiliary unit;

[0079] The pressure generating unit includes a drive system and an output end 21. The drive system includes a servo hydraulic system or a piezoelectric drive system 2. The drive system drives the output end 21 to move up and down.

[0080] The positioning clamp unit includes an upper pressure plate 3, a lower pressure plate 4, and a limiting groove 41. The limiting groove 41 is disposed in the middle of the lower pressure plate 4, and the upper pressure plate 3 is connected to the output end 21 of the pressure generating unit.

[0081] The temperature auxiliary unit includes a temperature control module and a heating module. The temperature control module includes a temperature sensor and a temperature controller 5 (existing modules such as a PLC integrated temperature control module can be used). The temperature sensor is disposed on the surface of the upper pressure plate 3 and the lower pressure plate 4. The heating module is integrated inside the upper pressure plate 3 and the lower pressure plate 4. The temperature control module controls the temperature of the upper pressure plate 3 and the lower pressure plate 4 through the heating module.

[0082] The temperature controller 5 controls the operation of the heating module based on the data monitored by the temperature sensor, thereby controlling the temperature of the upper pressure plate 3 and the lower pressure plate 4.

[0083] The pressure control unit includes a pressure sensor and a programmable PLC controller 1;

[0084] The pressure sensor is located at the output end 21 of the upper pressure plate 3, the lower pressure plate 4, or the pressure generating unit to monitor the pressure applied to the cell stack in real time.

[0085] The programmable controller is connected to the pressure sensor and the drive system, and controls the operation of the drive system based on the data from the pressure sensor.

[0086] The programmable controller is used to receive the signal from the pressure sensor, compare it with a preset pressure-time program, and output control commands to the drive system to drive the output terminal 21 to accurately execute the preset pressing method.

[0087] The heating module includes a heating rod or an infrared heating module.

[0088] Among them, the pressure generating unit adopts a servo hydraulic system or a piezoelectric drive system 2, which can output periodic pulse pressure, and the pressure amplitude adjustment range is 5-50 MPa;

[0089] Pressure control unit: It can collect pressure signals in real time and provide feedback adjustment to achieve precise control of the amplitude, frequency, and pulse width (duty cycle 30%-70%) of the pulse pressure;

[0090] Positioning clamp unit: The lower pressure plate 4 is fixed, the upper pressure plate 3 is connected to the output end 21 of the pressure generating unit, and the limiting groove 41 is used to limit the horizontal position of the battery cell stack to avoid stack displacement during the compaction process.

[0091] Temperature auxiliary unit: Integrated inside the upper pressure plate 3 and the lower pressure plate 4, it adopts a heating rod or infrared heating module to achieve temperature control of 25-80 ℃, which is used to help improve the interface wettability of the sulfide electrolyte sheet and avoid the electrolyte brittleness from increasing at low temperature.

[0092] In this embodiment, the servo hydraulic system, piezoelectric drive system, temperature sensor, temperature controller, heating module, pressure sensor, and programmable PLC controller can all be existing commercially available equipment or components, and their structure and working principle are already known, so they will not be described in detail here.

[0093] Example 2

[0094] This embodiment provides a method for pressing sulfide solid-state battery cells.

[0095] 1. Cell stacking configuration: The positive electrode is LiNi 0.8 Co 0.1 Mn 0.1O2 (100 μm thick), sulfide solid electrolyte membrane is Li6PS5Cl (70 μm thick), negative electrode is graphite (80 μm thick), and the total thickness of the stack is 200 μm.

[0096] The positive electrode, sulfide solid electrolyte sheet, and negative electrode are stacked in the order of "positive electrode-electrolyte-negative electrode" to form a cell stack. The stack is placed on the lower pressure plate 4 of the positioning fixture unit and fixed by the limiting groove 41.

[0097] 2. Equipment parameter settings (e.g.) Figure 2 ): Linear pressurization, linear depressurization, and pulse pressure parameters are set through the pressure control unit.

[0098] Pressurization phase: pressurize from 0 to 200 MPa in 2 minutes;

[0099] Pre-compression stage: amplitude 5-15 MPa, frequency 0.1 Hz, time 3 min;

[0100] Main pressure stage: amplitude 20-40 MPa, frequency 0.5 Hz, duration 5 min;

[0101] Holding pressure phase: amplitude 15-25 MPa, frequency 0.2 Hz, duration 3 min;

[0102] Depressurization phase: Pressure drops to 0 MPa over 2 minutes;

[0103] Temperature assistance: Platen temperature 50 ℃.

[0104] 3. Performance testing of the pressed battery cells: This is achieved through in-situ electrochemical impedance spectroscopy (IF 10). -2 -10 6 The interface impedance of the cell stack is detected by (Hz), and the cell cycle performance is tested by the Land test system.

[0105] The test results are as follows:

[0106] Interface impedance: 7.8Ω, cell area 3cm×4cm, area ratio interface impedance 93.6Ω·cm 2 ;

[0107] Cell cycle performance: At 25 ℃, 1 C charge and discharge, 80% capacity retention after 500 cycles.

[0108] Example 3

[0109] This embodiment provides a method for pressing sulfide solid-state battery cells.

[0110] 1. Cell layer configuration: The positive electrode is LiCoO2 (80 μm thick), and the sulfide solid electrolyte membrane is Li 10 GeP2S 12 (Thickness 100 μm), the negative electrode is a silicon-carbon composite negative electrode (thickness 60 μm), and the total thickness of the stack is 155 μm.

[0111] 2. Equipment parameter settings:

[0112] Pressurization phase: pressurize from 0 to 250 MPa in 3 minutes;

[0113] Pre-compression stage: amplitude 10-15 MPa, frequency 1 Hz, time 3 min;

[0114] Main pressure stage: amplitude 30-40 MPa, frequency 5 Hz, time 5 min;

[0115] Pressure holding phase: amplitude 15-25 MPa, frequency 1 Hz, duration 3 min;

[0116] Depressurization phase: Pressure drops to 0 MPa over 3 minutes;

[0117] Temperature assistance: Platen temperature 60 ℃.

[0118] 3. Performance test results:

[0119] Interface impedance: 6.2Ω, cell area 3cm×4cm, area ratio interface impedance 74.4Ω·cm 2 ;

[0120] Cell cycle performance: At 25 ℃, 1 C charge and discharge, 85% capacity retention after 500 cycles.

[0121] Comparative Example 1

[0122] This comparative example provides a method for pressing sulfide solid-state battery cells.

[0123] Using the same battery as in Example 2, linear pressurization (the pressurization rate is the same as in Example 2) is performed and the pressure is held for 11 minutes (pressure 200 MPa). All other parameters are the same (the other parameters refer to the linear pressurization rate and time. After the pressure holding period of linear pressurization is completed, the final step of depressurization is performed directly. The depressurization rate, time, and pressure plate temperature during the depressurization process are all the same as in Example 2).

[0124] Performance testing: Interface impedance 5460 Ω·cm 2 After 10 cycles at 1C, lithium plating occurred, and the package breakage rate was 50%.

[0125] Figure 3This is a comparison graph of the electrochemical impedance spectroscopy between Example 2 and Comparative Example 1 of the present invention. Figure 3 It can be seen that the semi-circular diameter of the interface impedance spectrum of the battery cell of Example 2 prepared by the method of the present invention is much smaller than that of Comparative Example 1, indicating that the solid-solid interface impedance is significantly reduced.

[0126] Figure 4 This is a comparison chart of the battery cycle performance of Example 2 and Comparative Example 1 of the present invention. Figure 4 It can be seen that the capacity decay curve of the battery cell in Example 2 is flat, and its cycle stability is much better than that of Comparative Example 1.

[0127] Finally, it should be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0128] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the invention.

[0129] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for pressing all-solid-state battery cells, characterized in that, The suppression method includes: S1. Pressurization stage: The battery cell stack is placed in a pressing device and pressure is applied to the battery cell stack. The pressure is linearly increased to the reference pressure to achieve initial contact between the positive electrode, solid electrolyte membrane and negative electrode of the battery cell stack. S2. Pre-pressurization stage: After the pressurization stage is completed, the temperature is kept constant, and the cell stack is subjected to the first pulse pressurization on the basis of the reference pressure to initially eliminate the voids in the cell stack; S3. Main pressure stage: After the pre-pressure stage is completed, the temperature is kept constant, and the cell stack is subjected to a second pulse pressurization on the basis of the reference pressure to achieve close contact between the positive electrode, solid electrolyte membrane and negative electrode of the cell stack; S4. Pressure Holding Stage: After the main pressure stage is completed, the temperature is kept constant, and the cell stack is subjected to a third pulse pressurization on the basis of the reference pressure to stabilize the interface contact state of the cell stack. S5. Pressure relief stage: After the pressure holding stage is completed, the temperature is kept constant and the pressure is linearly reduced to 0 MPa; After the pressure relief phase is completed, repeat steps S1 to S5 until the interface resistance is ≤100 Ω·cm. 2 To obtain finished battery cells.

2. The method for pressing an all-solid-state battery cell according to claim 1, characterized in that, The pressurization phase specifically includes: The battery cell stack is placed in a pressing device, and pressure is applied to the battery cell stack at 40-60 ℃. The pressure is linearly increased to a reference pressure of 100-300 MPa for 2-5 min to achieve initial contact between the positive electrode, solid electrolyte membrane and negative electrode of the battery cell stack. The solid electrolyte membrane includes any one of sulfide solid electrolyte membrane, oxide solid electrolyte membrane, polymer solid electrolyte membrane, halide solid electrolyte membrane and composite electrolyte solid electrolyte membrane.

3. The method for pressing an all-solid-state battery cell according to claim 1, characterized in that, The pre-compression stage specifically includes: After the pressurization stage is completed, the temperature is kept constant, and the cell stack is subjected to the first pulse pressurization based on the reference pressure. The pressure amplitude is ±5 to 15 MPa, the frequency is 0.1 to 1 Hz, the duty cycle is 30-70%, and the duration is 1 to 3 minutes, so as to initially eliminate the voids in the cell stack.

4. The method for pressing an all-solid-state battery cell according to claim 1, characterized in that, The main pressure stage specifically includes: After the pre-pressurization stage is completed, the temperature is kept constant, and the cell stack is subjected to a second pulse pressurization based on the reference pressure. The pressure amplitude is ±20 to 40 MPa, the frequency is 0.5 to 10 Hz, the duty cycle is 30-70%, and the duration is 3 to 8 minutes, so as to achieve close contact between the positive electrode, solid electrolyte membrane and negative electrode of the cell stack.

5. The method for pressing an all-solid-state battery cell according to claim 1, characterized in that, The pressure holding stage specifically includes: After the main pressure stage is completed, the temperature is kept constant, and the cell stack is subjected to a third pulse pressurization on the basis of the reference pressure. The pressure amplitude is ±15~25MPa, the frequency is 0.1~2 Hz, the duty cycle is 30-70%, and the duration is 1~3 min, so as to stabilize the interface contact state of the cell stack.

6. The method for pressing an all-solid-state battery cell according to claim 1, characterized in that, The depressurization stage specifically includes: After the pressure holding phase ends, the temperature remains constant, and the pressure decreases linearly from the reference pressure to 0 MPa, with the pressure relief lasting for 2-5 minutes. After the pressure relief phase is completed, repeat steps S1 to S5 until the interface resistance is ≤100 Ω·cm. 2 To obtain finished battery cells, specifically including: After the depressurization stage is completed, steps S1 to S5 are repeated ≥0 times. Each time this is repeated, the pressure amplitude of the main pressure stage is increased by 0.5-2 MPa until the measured interfacial impedance is ≤100 Ω·cm. 2 To obtain finished battery cells.

7. The application of the all-solid-state battery cell pressing method according to any one of claims 1-6 in the preparation of sulfide solid-state batteries, oxide solid-state batteries, polymer solid-state batteries, halide solid-state batteries, or composite electrolyte solid-state batteries.

8. A solid-state battery cell pressing apparatus for performing the solid-state battery cell pressing method as described in claim 1, characterized in that, The pressing device includes a pressure generating unit, a pressure control unit, a positioning clamp unit, and a temperature auxiliary unit; The pressure generating unit includes a drive system and an output end. The drive system includes a servo hydraulic system or a piezoelectric drive system, and the drive system drives the output end to move up and down. The positioning fixture unit includes an upper pressure plate, a lower pressure plate, and a limiting groove. The limiting groove is disposed in the middle of the lower pressure plate, and the upper pressure plate is connected to the output end of the pressure generating unit. The temperature auxiliary unit includes a temperature control module and a heating module. The temperature control module includes a temperature sensor and a temperature controller. The temperature sensor is disposed on the surface of the upper pressure plate and the lower pressure plate. The heating module is integrated inside the upper pressure plate and the lower pressure plate. The temperature control module controls the temperature of the upper pressure plate and the lower pressure plate through the heating module.

9. The all-solid-state battery cell pressing equipment according to claim 8, characterized in that, The pressure control unit includes a pressure sensor and a programmable controller; The pressure sensor is located at the output end of the upper pressure plate, the lower pressure plate, or the pressure generating unit to monitor the pressure applied to the cell stack in real time. The programmable controller is connected to the pressure sensor and the drive system, and controls the operation of the drive system based on the data from the pressure sensor.

10. The all-solid-state battery cell pressing equipment according to claim 8, characterized in that, The heating module includes a heating rod or an infrared heating module.

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