An electrochemical formation method and apparatus for all-solid-state pouch batteries

Abstract

This invention provides an electrochemical formation method and apparatus for all-solid-state pouch batteries, belonging to the field of solid-state battery technology. The formation method includes: placing the all-solid-state pouch battery to be formed in an elastic pressure-bearing bag, venting the air from the bag and sealing it, then placing it in an isostatic chamber, injecting a pressure medium, raising the pressure in the isostatic chamber to 50-300 MPa, and maintaining it for 5-15 minutes; maintaining pressure stability, performing electrochemical formation on the all-solid-state pouch battery using a constant current-constant voltage charging mode; after completion, lowering the temperature of the pressure medium to 20-25°C and holding it at that temperature for 10-30 minutes to stabilize the interface layer; finally, lowering the pressure in the isostatic chamber to atmospheric pressure to obtain the formed all-solid-state pouch battery. This method can effectively improve the solid-solid interface stability of all-solid-state pouch batteries, suppress lithium dendrites, and effectively improve the overall performance of all-solid-state pouch batteries.

Description

Technical Field

[0001] This invention belongs to the field of solid-state battery technology, and specifically relates to an electrochemical formation method and apparatus for an all-solid-state pouch cell. Background Technology

[0002] All-solid-state lithium batteries are considered a key development direction for next-generation energy storage devices due to their high safety and high energy density. However, their core challenge lies in the instability of the solid-solid interface, including the interface between the positive electrode active material and the solid electrolyte, and the interface between the negative electrode and the solid electrolyte. In particular, during the first charge (formation) process, lithium ions are released from the positive electrode and undergo a reduction reaction on the negative electrode side.

[0003] In traditional liquid batteries, the liquid electrolyte wets the electrodes, forming good ion contact. However, in all-solid-state batteries, the contact between the solid electrolyte and electrode particles is rigid. During formation, the negative electrode material (such as lithium metal, graphite, silicon-based materials, etc.) undergoes volume expansion / contraction, easily generating micropores and cracks at the interface, leading to interface contact failure and a sharp increase in interface impedance. More seriously, uneven interface contact can cause uneven distribution of lithium ion flow, resulting in concentrated deposition at certain contact points, forming lithium dendrites, which can eventually pierce the solid electrolyte, causing an internal short circuit and posing a safety hazard.

[0004] In existing technologies, a static initial pressure is typically applied during battery assembly, or a rigid clamp is used on the outside of the battery. However, this method cannot adapt to the dynamic volume changes of the electrode materials during formation, and the pressure distribution is uneven, easily causing stress concentration at the edges of the pouch cell, failing to fundamentally solve the problem of interface contact deterioration. Therefore, there is an urgent need for a new method that can dynamically and uniformly maintain tight interface contact during the electrochemical formation of all-solid-state pouch cells. Summary of the Invention

[0005] To address the issue of interface instability in all-solid-state lithium batteries, this invention provides an electrochemical formation method for all-solid-state pouch batteries. This method can effectively improve the solid-solid interface stability of all-solid-state pouch batteries, suppress lithium dendrites, and effectively enhance the overall performance of all-solid-state pouch batteries.

[0006] The present invention also provides an electrochemical formation device for all-solid-state pouch batteries.

[0007] This invention is achieved through the following technical solution:

[0008] This invention provides an electrochemical formation method for an all-solid-state pouch cell, the formation method comprising:

[0009] The soft-pack battery to be converted into an all-solid-state battery is placed in an elastic pressure-bearing bag. After the air inside the elastic pressure-bearing bag is expelled, it is sealed so that the elastic pressure-bearing bag and the soft-pack battery to be converted into an all-solid-state battery are tightly fitted together to obtain a sealed battery assembly.

[0010] The sealed battery assembly is placed in an isostatic chamber, and a pressure medium is injected into the isostatic chamber to raise the pressure in the isostatic chamber to 50-300 MPa at a rate of 5-100 MPa / min and maintain it for 5-15 min.

[0011] Maintaining stable pressure within the isostatic chamber, the electrochemical formation of the all-solid-state soft-pack battery to be formed is carried out using a constant current-constant voltage charging mode.

[0012] After the electrochemical formation is completed, the pressure inside the isostatic chamber is kept stable, the temperature of the pressure medium is reduced to 20-25 °C, and kept at that temperature for 10-30 min to complete the interface layer stabilization.

[0013] After the heat preservation is completed, the pressure inside the isostatic chamber is reduced to atmospheric pressure at a rate of 5-100 MPa / min to obtain a fully solid-state pouch cell that has been formed.

[0014] Preferably, the elastic pressure-bearing bag is made of fluororubber or polytetrafluoroethylene composite material, and the thickness of the elastic pressure-bearing bag is 0.1 to 0.5 mm.

[0015] Preferably, the polytetrafluoroethylene composite material comprises reinforcing fibers (selected from glass fiber, carbon fiber, polyimide fiber, etc.) and high-temperature resistant fillers (selected from silica, alumina, etc.). The mass ratio of reinforcing fibers to high-temperature resistant fillers is specifically determined according to the material type to improve its mechanical strength and corrosion resistance.

[0016] Furthermore, placing the sealed battery assembly within an isostatic chamber and injecting a pressure medium into the isostatic chamber specifically includes:

[0017] The sealed battery assembly is placed in an isostatic chamber, and a pressure medium is injected into the isostatic chamber.

[0018] The pressure medium includes silicone oil or fluorinated liquid, and the temperature of the pressure medium is controlled between 20 and 60 °C.

[0019] Furthermore, maintaining the pressure stability within the isostatic chamber and performing electrochemical formation of the all-solid-state pouch battery to be formed using a constant current-constant voltage charging mode specifically includes: maintaining the pressure stability within the isostatic chamber, performing electrochemical formation of the all-solid-state pouch battery to be formed using a constant current-constant voltage charging mode, and controlling the temperature of the pressure medium at 25–30 °C.

[0020] Furthermore, the electrochemical formation of the all-solid-state pouch battery to be formed using a constant current-constant voltage charging mode specifically includes:

[0021] Constant current stage: The battery to be converted into a solid-state soft-pack battery is charged to the battery charging cut-off voltage with a current of 0.05~0.1 C;

[0022] Constant voltage stage: Maintain the cutoff voltage until the current drops to 0.05 C;

[0023] Discharge stage: Discharge the all-solid-state pouch cell to the discharge cutoff voltage using a current of 0.05 to 0.1 C.

[0024] Furthermore, after the heat preservation is completed, the pressure inside the isostatic chamber is reduced to atmospheric pressure at a rate of 5–100 MPa / min to obtain a fully solid-state pouch battery that has completed formation, specifically including:

[0025] After the heat preservation is completed, the pressure inside the isostatic chamber is reduced to below 0.1 MPa at a rate of 5-100 MPa / min. The elastic pressure-bearing bag is then removed and opened to obtain the fully solid-state soft-pack battery that has been formed.

[0026] Furthermore, the all-solid-state soft-pack battery to be formed is assembled from a positive electrode, a negative electrode, a solid electrolyte layer, and an aluminum-plastic composite film.

[0027] Based on the same inventive concept, this invention provides an application of an electrochemical formation method for all-solid-state pouch cells in the preparation of all-solid-state or semi-solid-state cells.

[0028] Furthermore, when preparing a semi-solid-state battery using the above-mentioned electrochemical formation method for all-solid-state pouch batteries, simply replace the all-solid-state pouch battery to be formed with the semi-solid-state pouch battery to be formed, while keeping the other steps and process parameters unchanged.

[0029] Based on the same inventive concept, the present invention also provides an electrochemical formation device for an all-solid-state soft-pack battery, the electrochemical formation device comprising an isostatic chamber, a pressure control system, a temperature control system, an electrochemical formation module, and an elastic pressure-bearing component.

[0030] The pressure control system includes an inlet pipe, an outlet pipe, a pressure sensor, and a PLC controller. The pressure sensor is installed inside the isostatic chamber. Both the inlet pipe and the outlet pipe are connected to the cavity of the isostatic chamber. A high-pressure pump is installed on the inlet pipe, and a pressure relief valve is installed on the outlet pipe. The PLC controller controls the opening and closing of the high-pressure pump and the pressure relief valve based on the monitoring data of the pressure sensor.

[0031] The temperature control system includes a heating tube, a cooling coil, a temperature sensor, and a temperature controller. The temperature sensor is installed inside the isostatic chamber. The heating tube and the cooling coil are attached to the outer wall of the isostatic chamber. The temperature controller controls the operation of the heating tube and the cooling coil based on the monitoring data of the temperature sensor.

[0032] The electrochemical formation module includes a DC power supply, electrode clamps, and a data acquisition unit.

[0033] The elastic pressure-bearing assembly includes an elastic pressure-bearing bag and a sealing joint. The sealing joint is connected to one end of the elastic pressure-bearing bag and has an exhaust hole and an electrode lug outlet hole.

[0034] Furthermore, the exhaust port is equipped with a closable valve, and the electrode lead-out hole is equipped with an insulating sealing ring;

[0035] The inner wall of the isostatic chamber is coated with a corrosion-resistant coating.

[0036] One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

[0037] 1. This invention discloses an electrochemical formation method for all-solid-state pouch batteries. This method involves simultaneously applying uniform isostatic pressure during the electrochemical formation process of the solid-state battery. On one hand, the simultaneously applied isostatic pressure can adapt to the dynamic volume changes of the electrode materials during formation, avoiding interfacial contact failure caused by volume changes of the negative electrode material. On the other hand, compared with traditional rigid clamps, uniform isostatic pressure enables a more uniform pressure distribution in the solid-state battery, which is more conducive to maintaining tight interfacial contact. This method effectively improves the interfacial stability of the solid-state battery and suppresses lithium dendrite formation by dynamically and uniformly optimizing the solid-solid interface during formation, thereby enhancing the overall performance of the battery.

[0038] 2. The present invention discloses an electrochemical formation device for an all-solid-state soft-pack battery. This device dynamically controls the medium pressure and temperature inside the isostatic chamber through a pressure control system and a temperature control system, so that the solid-state battery in the elastic pressure-bearing bag is simultaneously subjected to uniform isostatic pressure during the electrochemical formation process. The device uses an electrochemical formation module to realize the electrochemical formation of the solid-state battery. The elastic pressure-bearing bag in the elastic pressure-bearing assembly is used to seal the solid-state battery, and the sealing joint is used to discharge the air inside the elastic pressure-bearing bag and realize the connection between the electrode clamp of the electrochemical formation module and the electrode of the solid-state battery. Attached Figure Description

[0039] 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.

[0040] Figure 1 This is a schematic diagram of the electrochemical formation device for the all-solid-state soft-pack battery of the present invention.

[0041] Figure 2 This is a schematic diagram of the sealing joint of the electrochemical formation device for the all-solid-state soft-pack battery of the present invention.

[0042] Figure 3 This is a comparison diagram of the electrochemical impedance of Example 2 and the comparative example of the present invention.

[0043] Figure 4 This is a comparison chart of the battery cycle performance of Embodiment 2 and the comparative example of the present invention.

[0044] Reference numerals: 1-Isostatic chamber, 2-All-solid-state soft-pack battery, 2-1-Positive electrode tab, 2-2-Negative electrode tab, 2-3-Positive electrode tab clamp and connecting wire, 2-4-Negative electrode tab clamp and connecting wire, 3-Inlet pipe, 31-High-pressure pump, 4-Outlet pipe, 41-Pressure relief valve, 5-Pressure sensor, 6-PLC controller, 7-Temperature sensor, 8-Heating tube and cooling coil, 9-Temperature controller, 10-Elastic pressure-bearing bag, 11-Sealing joint, 12-Electrochemical formation and testing system. Detailed Implementation

[0045] 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.

[0046] 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.

[0047] 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.

[0048] The technical principle of this invention is as follows:

[0049] This invention provides an electrochemical formation method for an all-solid-state pouch cell, the formation method comprising:

[0050] S1. Place the soft-pack battery to be converted into an all-solid-state battery in an elastic pressure-bearing bag, expel the air from the elastic pressure-bearing bag and seal it, so that the elastic pressure-bearing bag and the soft-pack battery to be converted into an all-solid-state battery are tightly fitted together to obtain a sealed battery assembly.

[0051] S2. Place the sealed battery assembly in an isostatic chamber, inject a pressure medium into the isostatic chamber, and raise the pressure in the isostatic chamber to 50-300 MPa at a rate of 5-100 MPa / min, and maintain it for 5-15 min.

[0052] S3. Maintain the pressure inside the isostatic chamber and perform electrochemical formation of the all-solid-state soft-pack battery to be formed using a constant current-constant voltage charging mode.

[0053] S4. After the electrochemical formation is completed, maintain the pressure inside the isostatic chamber and reduce the temperature of the pressure medium to 20-25°C, keep it at that temperature for 10-30 minutes to complete the interface layer stabilization.

[0054] S5. After the heat preservation is completed, the pressure inside the isostatic chamber is reduced to atmospheric pressure at a rate of 5-100 MPa / min to obtain a fully solid-state pouch battery that has been formed.

[0055] The elastic pressure-bearing bag is made of fluororubber or polytetrafluoroethylene composite material that is resistant to electrolyte corrosion, and the thickness of the elastic pressure-bearing bag is 0.1 to 0.5 mm.

[0056] Furthermore, placing the sealed battery assembly within an isostatic chamber and injecting a pressure medium into the isostatic chamber specifically includes:

[0057] The sealed battery assembly is placed in an isostatic chamber, and a pressure medium is injected into the isostatic chamber.

[0058] The pressure medium comprises insulating and chemically inert silicone oil or fluorinated liquid, and the temperature of the pressure medium is controlled at 20–60 °C. In step S2 of this invention, the pressure inside the isostatic chamber is increased to 50–300 MPa at a rate of 5–100 MPa / min and maintained for 5–15 minutes to allow the solid electrolyte to initially adhere to the electrode.

[0059] In this invention, the temperature of the pressure medium is controlled between 20 and 60 °C. Within this temperature range, the viscosity of the pressure medium (silicone oil / fluorinated liquid) is moderate, and its fluidity is good, which is conducive to uniform pressure transmission. At the same time, it avoids thermal runaway of the battery due to high temperature or solidification of the medium due to low temperature. If the temperature is too high: the viscosity of the medium decreases, which may lead to leakage; the side reactions at the battery interface are aggravated; if the temperature is too low: the viscosity of the medium increases, resulting in uneven pressure transmission; the battery interface impedance increases.

[0060] Step S3 specifically includes: maintaining the pressure inside the isostatic chamber stable, using a constant current-constant voltage charging mode to electrochemically form the all-solid-state soft-pack battery to be formed, and controlling the temperature of the pressure medium at 25-30 ℃.

[0061] In this invention, the temperature of the pressure medium is controlled at 25-30°C, which is close to room temperature. This temperature is beneficial to the stability of the battery interface and reduces thermal stress. At the same time, it facilitates the energy-saving operation of the temperature control system. If the temperature is too high, it may cause interfacial side reactions; if the temperature is too low, the interfacial ion conduction rate will decrease.

[0062] Furthermore, the electrochemical formation of the all-solid-state pouch battery to be formed using a constant current-constant voltage charging mode specifically includes:

[0063] Constant current stage: The battery to be converted into a solid-state soft-pack battery is charged to the battery charging cut-off voltage with a current of 0.05~0.1 C;

[0064] Constant voltage stage: Maintain the cutoff voltage until the current drops to 0.05 C;

[0065] Discharge stage: Discharge the all-solid-state pouch cell to the discharge cutoff voltage using a current of 0.05 to 0.1 C.

[0066] In this invention, the "constant current-constant voltage charging" method is an existing method, with a total duration of approximately 22-24 hours for the three stages. However, this invention performs constant current-constant voltage charging simultaneously under high voltage isostatic pressure, which can effectively suppress the generation of interface porosity and improve interface stability.

[0067] In this invention, the specific values ​​of the charging cut-off voltage and the discharging cut-off voltage are set according to the positive / negative electrode materials of the battery.

[0068] After electrochemical formation in step S4, the pressure inside the isostatic chamber is maintained stable, and the temperature of the pressure medium is reduced to 20–25 °C and held for 10–30 min. The principle behind this interface layer stabilization is that during the pressure holding and cooling process, the stress at the interface gradually relaxes, resulting in a tighter contact between the solid electrolyte and the electrode, forming a stable interface layer. The benefits include improved interfacial mechanical strength and chemical stability, and extended cycle life.

[0069] Step S5 specifically includes:

[0070] After the heat preservation is completed, the pressure inside the isostatic chamber is reduced to below 0.1 MPa at a rate of 5-100 MPa / min. The elastic pressure-bearing bag is then removed and opened to obtain the fully solid-state soft-pack battery that has been formed.

[0071] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0072] The following will provide a detailed description of the electrochemical formation method and apparatus for an all-solid-state soft-pack battery according to the present invention, in conjunction with embodiments and experimental data.

[0073] Example 1

[0074] This embodiment provides an electrochemical formation device for an all-solid-state pouch battery, such as... Figure 1 , 2 As shown, the electrochemical formation device includes an isostatic chamber 1, a pressure control system, a temperature control system, an electrochemical formation module, and an elastic pressure-bearing component.

[0075] The pressure control system includes an inlet pipe 3, an outlet pipe 4, a pressure sensor 5, and a PLC controller 6. The pressure sensor 5 is installed inside the isostatic pressure chamber 1. The inlet pipe 3 and the outlet pipe 4 are both connected to the inner cavity of the isostatic pressure chamber 1. A high-pressure pump 31 is installed on the inlet pipe 3, and a pressure relief valve 41 is installed on the outlet pipe 4. The PLC controller 6 controls the opening and closing of the high-pressure pump 31 and the pressure relief valve 41 based on the monitoring data of the pressure sensor 5.

[0076] The temperature control system includes a heating tube, a cooling coil 8, a temperature sensor 7, and a temperature controller 9. The temperature sensor 7 is installed inside the isostatic chamber 1. The heating tube and the cooling coil are attached to the outer wall of the isostatic chamber 1. The temperature controller 9 controls the operation of the heating tube and the cooling coil based on the monitoring data of the temperature sensor 7.

[0077] The electrochemical formation module includes a DC power supply, a tab clamp, and a data acquisition unit; the elastic pressure-bearing assembly includes an elastic pressure-bearing bag 10 and a sealing joint 11, the sealing joint 11 being connected to one end of the elastic pressure-bearing bag 10, and the sealing joint 11 having an exhaust hole and a tab outlet hole.

[0078] The electrode clamp includes a positive electrode clamp and a negative electrode clamp. The positive electrode clamp and the negative electrode clamp are used to connect the positive electrode 2-1 and the negative electrode 2-2 of the all-solid-state soft-pack battery 2, respectively. The positive electrode clamp and the negative electrode clamp are connected to the electrochemical formation and testing system 12 via connecting wires, which pass through the electrode lead-out holes in the sealing connector 11. The positive electrode clamp and the connecting wires are shown in the attached figure. Figure 2 As shown in Figure 2-3, the negative electrode tab clamp and connecting wire are as follows. Figure 2 As shown in Figure 2-4.

[0079] The vent is equipped with a closable valve, and the tab outlet is equipped with an insulating sealing ring.

[0080] In this embodiment, the isostatic pressure chamber 1 is made of stainless steel with a corrosion-resistant coating on the inner wall, and has a volume of 0.05 m³. 3 It is equipped with a pressure sensor 5 (accuracy ±0.005 MPa) and a temperature sensor 7 (accuracy ±0.5 ℃).

[0081] Pressure control system: can achieve precise adjustment within a pressure range of 50-300 MPa, with an adjustment accuracy of ±0.01 MPa.

[0082] Temperature control system: can adjust the medium temperature within the range of 20-60 ℃.

[0083] Electrochemical formation module: includes DC power supply (output current 0.001-10 A, voltage 0-5 V), electrode clamp (copper material, gold-plated surface) and data acquisition unit, which can monitor charging current, voltage and battery temperature in real time.

[0084] Flexible pressure-bearing components: ensure uniform pressure transmission without affecting electrochemical connections.

[0085] In this embodiment, the isostatic pressure chamber 1, PLC controller 6, temperature controller 9, DC power supply, pressure sensor 5, temperature sensor 7, and heating / cooling pipe all adopt existing structures or equipment, and their structures and working principles are also existing, so they will not be described in detail here.

[0086] Example 2

[0087] This embodiment provides an electrochemical formation method for an all-solid-state pouch cell.

[0088] Cell to be formed: Positive electrode LiNi 0.8 Co 0.1 Mn 0.1 O2, graphite as the negative electrode, and Li6PS5Cl as the solid electrolyte, all of which are soft-pack batteries are encapsulated with aluminum-plastic film, and the battery size is 3cm×4cm.

[0089] Elastic pressure-bearing bag: made of fluororubber, 0.4 mm thick;

[0090] Pressure medium: silicone oil, initial temperature 30 ℃.

[0091] Process parameters:

[0092] Pre-pressurization: Silicone oil is injected into the isostatic chamber in Example 1. The PLC controller controls the high-pressure pump to increase the pressure to 200 MPa at a rate of 50 MPa / min and maintain it for 10 min.

[0093] Formation: Maintaining stable pressure, the electrochemical formation module charges the battery to be formed to 4.2 V at a constant current of 0.1 C, then maintains constant voltage until the current drops to 0.05 C, and discharges to 2.5 V at a current of 0.1 C;

[0094] Pressure holding and cooling: Maintain a pressure of 200 MPa, and use the temperature controller to control the cooling coil to cool the medium to 25 ℃ and hold for 20 minutes;

[0095] Depressurization and removal: Open the pressure relief valve and slowly depressurize to atmospheric pressure (below 0.1 MPa) at a rate of 50 MPa / min. Remove the elastic pressure-bearing bag and open it to obtain the fully formed solid-state soft-pack battery 2.

[0096] The performance of the battery after formation in this embodiment was tested. Interface impedance: Electrochemical impedance spectroscopy (EIS) was used, with a frequency range of 0.1 Hz to 7 MHz and an amplitude of 5 mV. Cycle performance: At 25°C, the battery was charged and discharged at 1 C for 100 to 200 cycles, and the capacity retention rate was recorded. Test instruments: Electrochemical workstation and battery test system.

[0097] Performance test results: interface impedance 7.6 Ω, capacity retention of 92% after 150 cycles at 1 C, and package integrity of 100%.

[0098] Example 3

[0099] This embodiment provides an electrochemical formation method for an all-solid-state pouch cell.

[0100] Battery to be formed: Positive electrode LiCoO2, negative electrode Si-C composite material, solid electrolyte Li 10 GeP2S 12 All of their soft-pack batteries are encapsulated in aluminum-plastic film, and the battery size is 3cm × 4cm.

[0101] Elastic pressure-bearing bag: polytetrafluoroethylene composite material, 0.5 mm thick;

[0102] Pressure medium: fluorinated liquid, initial temperature 30 ℃.

[0103] Process parameters:

[0104] Pre-pressurization: Increase pressure from 50 MPa / min to 300 MPa and maintain for 10 min;

[0105] Formation: Maintain stable pressure, charge at a constant current of 0.1 C to 4.5 V, then maintain constant voltage until the current drops to 0.05 C, and discharge at a current of 0.1 C to 2.5 V;

[0106] Pressure holding and cooling: Maintain a pressure of 300 MPa, cool down to 25 ℃, and hold for 15 min;

[0107] Depressurization and removal: Slowly depressurize to below 0.1 MPa at a rate of 50 MPa / min, remove the elastic pressure-bearing bag, and open it to obtain the fully formed solid-state soft-pack battery 2.

[0108] The battery prepared in this embodiment was subjected to performance tests: interface impedance 5.2 Ω, capacity retention of 95% after 150 cycles at 1 C, and package integrity of 100%.

[0109] Comparative Example 1

[0110] This comparative example provides a formation method for an all-solid-state pouch cell (traditional rigid platen pressing).

[0111] The same solid-state battery as in Example 2 was used, and pressure was applied by upper and lower rigid plates (pressure 200 MPa). Except for the different pressure application method, the other parameters, including formation temperature, time (pre-pressurization, pressure holding and cooling, and pressure release), battery size, and test method, were all consistent with those in Example 2.

[0112] The performance of the battery prepared in this comparative example was tested: the interface impedance was 265 Ω, lithium plating occurred after 10 cycles at 1 C, and the package breakage rate was 50%.

[0113] Comparative Example 2

[0114] This comparative example uses the same solid-state battery as Example 2, which undergoes pre-pressurization, pressure holding, and pressure release under isostatic pressure conditions. The battery is removed from the isostatic pressure chamber only during electrochemical formation. No further pressurization is applied during the formation process. All other process parameters, such as formation temperature, current, time (pre-pressurization, pressure holding and cooling, and pressure release), pressure, battery size, and testing methods, remain the same as in Example 2.

[0115] The performance of the battery prepared in this comparative example was tested: the interface impedance was 145 Ω, lithium plating occurred after 10 cycles at 1 C, and the package breakage rate was 30%.

[0116] Figure 3 This is a comparison graph of the electrochemical impedance spectroscopy of Example 2 of the present invention with Comparative Examples 1 and 2. Figure 3 It can be seen that the impedance of Example 2 is significantly lower than that of Comparative Example 1 and Comparative Example 2, indicating that isostatic pressure formation can effectively improve the interfacial contact between battery electrodes and reduce interfacial impedance.

[0117] Figure 4 This is a comparison chart of the battery cycle performance of Example 2 of the present invention with Comparative Examples 1 and 2. Figure 4 It can be seen that the cycle stability of Example 2 is much higher than that of Comparative Example 1 and Comparative Example 2, and the capacity decay is slower, indicating that the interface stabilization effect of the battery is significant.

[0118] 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.

[0119] 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.

[0120] 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 electrochemical formation of an all-solid-state pouch cell, characterized in that, The formation method includes: The soft-pack battery to be converted into an all-solid-state battery is placed in an elastic pressure-bearing bag. After the air inside the elastic pressure-bearing bag is expelled, it is sealed so that the elastic pressure-bearing bag and the soft-pack battery to be converted into an all-solid-state battery are tightly fitted together to obtain a sealed battery assembly. The sealed battery assembly is placed in an isostatic chamber, and a pressure medium is injected into the isostatic chamber to raise the pressure in the isostatic chamber to 50-300 MPa at a rate of 5-100 MPa / min and maintain it for 5-15 min. Maintaining stable pressure within the isostatic chamber, the electrochemical formation of the all-solid-state soft-pack battery to be formed is carried out using a constant current-constant voltage charging mode. After the electrochemical formation is completed, the pressure inside the isostatic chamber is kept stable, the temperature of the pressure medium is reduced to 20-25 °C, and kept at that temperature for 10-30 min to complete the interface layer stabilization. After the heat preservation is completed, the pressure inside the isostatic chamber is reduced to atmospheric pressure at a rate of 5-100 MPa / min to obtain a fully solid-state pouch cell that has been formed.

2. The electrochemical formation method for an all-solid-state pouch cell according to claim 1, characterized in that, The elastic pressure-bearing bag is made of fluororubber or polytetrafluoroethylene composite material, and the thickness of the elastic pressure-bearing bag is 0.1 to 0.5 mm.

3. The electrochemical formation method for an all-solid-state pouch cell according to claim 1, characterized in that, The step of placing the sealed battery assembly in an isostatic chamber and injecting a pressurized medium into the isostatic chamber specifically includes: The sealed battery assembly is placed in an isostatic chamber, and a pressure medium is injected into the isostatic chamber. The pressure medium includes silicone oil or fluorinated liquid, and the temperature of the pressure medium is controlled between 20 and 60 °C.

4. The electrochemical formation method for an all-solid-state pouch cell according to claim 1, characterized in that, Maintaining pressure stability within the isostatic chamber and employing a constant current-constant voltage charging mode to electrochemically form the all-solid-state pouch battery to be formed specifically includes: Maintaining stable pressure within the isostatic chamber, the electrochemical formation of the all-solid-state soft-pack battery to be formed is carried out using a constant current-constant voltage charging mode, while controlling the temperature of the pressure medium at 25–30 °C.

5. The electrochemical formation method for an all-solid-state pouch cell according to claim 4, characterized in that, The electrochemical formation of the all-solid-state pouch cell to be formed using a constant current-constant voltage charging mode specifically includes: Constant current stage: The battery to be converted into a solid-state soft-pack battery is charged to the battery charging cut-off voltage with a current of 0.05~0.1 C; Constant voltage stage: Maintain the cutoff voltage until the current drops to 0.05 C; Discharge stage: Discharge the all-solid-state pouch cell to the discharge cutoff voltage using a current of 0.05 to 0.1 C.

6. The electrochemical formation method for an all-solid-state pouch cell according to claim 1, characterized in that, After the heat preservation process is completed, the pressure inside the isostatic chamber is reduced to atmospheric pressure at a rate of 5–100 MPa / min to obtain a fully solid-state pouch battery that has completed formation, specifically including: After the heat preservation is completed, the pressure inside the isostatic chamber is reduced to below 0.1 MPa at a rate of 5-100 MPa / min. The elastic pressure-bearing bag is then removed and opened to obtain the fully solid-state soft-pack battery that has been formed.

7. The electrochemical formation method for an all-solid-state pouch cell according to claim 1, characterized in that, The all-solid-state soft-pack battery to be formed is assembled from a positive electrode, a negative electrode, a solid electrolyte layer, and an aluminum-plastic composite film.

8. The application of the electrochemical formation method for all-solid-state pouch cells according to any one of claims 1-7 in the preparation of all-solid-state cells or semi-solid-state cells.

9. An electrochemical formation apparatus for an all-solid-state pouch cell, used to perform the electrochemical formation method for an all-solid-state pouch cell as described in claim 1, characterized in that, The electrochemical formation device includes an isostatic chamber, a pressure control system, a temperature control system, an electrochemical formation module, and an elastic pressure-bearing component. The pressure control system includes an inlet pipe, an outlet pipe, a pressure sensor, and a PLC controller. The pressure sensor is installed inside the isostatic chamber. Both the inlet pipe and the outlet pipe are connected to the cavity of the isostatic chamber. A high-pressure pump is installed on the inlet pipe, and a pressure relief valve is installed on the outlet pipe. The PLC controller controls the opening and closing of the high-pressure pump and the pressure relief valve based on the monitoring data of the pressure sensor. The temperature control system includes a heating tube, a cooling coil, a temperature sensor, and a temperature controller. The temperature sensor is installed inside the isostatic chamber. The heating tube and the cooling coil are attached to the outer wall of the isostatic chamber. The temperature controller controls the operation of the heating tube and the cooling coil based on the monitoring data of the temperature sensor. The electrochemical formation module includes a DC power supply, electrode clamps, and a data acquisition unit. The elastic pressure-bearing assembly includes an elastic pressure-bearing bag and a sealing joint. The sealing joint is connected to one end of the elastic pressure-bearing bag and has an exhaust hole and an electrode lug outlet hole.

10. The electrochemical formation apparatus for an all-solid-state pouch battery according to claim 9, characterized in that, The exhaust port is equipped with a closable valve, and the electrode lead-out hole is equipped with an insulating sealing ring; The inner wall of the isostatic chamber is coated with a corrosion-resistant coating.

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