Method for optimizing electrochemical performance of battery by external pressure and experimental platform

Abstract

The invention provides a method for optimizing electrochemical performance of a battery by external pressure and an experimental platform. According to the method, the battery structure of the lithium battery is adjusted by applying a certain external pressure, so that the electrochemical performance of the lithium battery is improved, and the capacity, cycling stability and safety of the battery are improved. The method comprises the following steps: firstly, placing a lithium battery in a pressurizing device, and applying a certain external pressure by accurately controlling a pressurizing system; then, performing a charge-discharge cycle test on the lithium battery while applying pressure, and monitoring electrochemical parameters such as pressure, voltage, capacity, internal resistance and the like of the battery in real time; and the optimal pressure range is determined by comparing the change of the battery performance under different external pressures. According to the method, the cycle performance of the lithium battery and the lithium ion hybrid capacitor can be effectively optimized, the capacity fading of the battery is reduced, the safety of the battery is improved, and the method has remarkable technical advantages and application prospects and is particularly suitable for development and application of the high-energy-density lithium battery and the lithium ion hybrid capacitor.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium batteries, and particularly to a method for optimizing the electrochemical performance of batteries (such as lithium batteries, lithium-ion hybrid capacitors (lithium-ion hybrid)) under external pressure and an experimental platform. Background Art

[0002] With the rapid development of new energy technologies, lithium batteries, as a new type of energy storage device, have been widely used in fields such as electric vehicles, portable electronic devices, and renewable energy storage systems due to their advantages in energy density and power density. However, in actual applications, existing lithium batteries still face challenges in aspects such as energy density, cycle stability, and charge-discharge efficiency. Especially under high power density and long-term use conditions, the electrochemical performance of the battery is often significantly affected, restricting its widespread application.

[0003] In recent years, researchers have begun to explore ways to improve the performance of lithium batteries and lithium-ion hybrids by changing electrode materials, optimizing electrolyte formulations, and designing new capacitor structures. However, although certain progress has been made, most of these methods focus on material-level optimization and have not fully explored the influence of external factors (such as external pressure) on the electrochemical performance of lithium batteries. For example, appropriate pressure in the formation process can reduce the internal stress during the charge and discharge of lithium batteries, slow down the expansion and contraction of electrode materials, and prevent material rupture and electrolyte failure inside the battery, thereby extending the service life of the battery.

[0004] Therefore, the object of the present invention is to propose a method for optimizing the electrochemical performance of batteries under external pressure. Within a certain range, moderate external pressure can promote the migration of lithium ions, enhance the electrochemical reaction of the battery, and thus improve the capacity and cycle life of the battery. The present invention is simple, efficient, and controllable, improving the safety, stability, and cycle life of lithium batteries. Summary of the Invention

[0005] The object of the present invention is to provide a method for optimizing the electrochemical performance of batteries under external pressure and an experimental platform. This method optimizes the performance of lithium batteries by applying appropriate external pressure, and regulates the capacity of lithium batteries and improves the cycle life based on external pressure. By applying a certain degree of external pressure during the operation of lithium batteries, the electrochemical performance of the battery is effectively improved, thereby increasing the capacity and cycle life of the battery. According to the technical solution of the present invention, the magnitude of external pressure has an important influence on battery performance. Appropriate pressure can improve the electrochemical reaction process of the battery without damaging the structure of the lithium battery, while excessive pressure may have a negative impact on the cycle life and capacity of the battery.

[0006] To achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is:

[0007] In a first aspect, the present invention provides a method for optimizing the electrochemical performance of a battery by external pressure, and the method includes the following:

[0008] Obtain batteries after formation processes with different nominal capacity sizes and different types;

[0009] Gradually apply an external pressure to each battery during the battery cycling process, obtain the change curve of the capacity under different external pressures with respect to the battery cycling process, find the external pressure value corresponding to the curve with a larger capacity and smaller fluctuations, and obtain the optimal pressure range and the optimal pressure for this type of battery;

[0010] Each type of battery corresponds to an optimal pressure range, and all types of batteries and their corresponding optimal pressure ranges constitute an optimization database;

[0011] Train an intelligent algorithm model with the optimization database, where the input of the intelligent algorithm model is the nominal capacity and the battery type, and the output is the optimal pressure range;

[0012] Input the nominal capacity and the battery type of the battery to be optimized into the trained intelligent algorithm model, determine the optimal pressure range of the battery to be optimized, and apply an external pressure within the optimal pressure range to the battery to be optimized to promote the migration of ions inside the battery, thereby achieving the optimization of the high battery capacity and cycle life of the battery.

[0013] Further, set a capacity decay threshold and a capacity change amount threshold. If the capacity value of each cycle during the battery cycling process is not less than the capacity decay threshold and the capacity change amount of each cycle is not greater than the capacity change amount threshold, then this external pressure value is within the optimal pressure range; otherwise, it is not within the optimal pressure range. At the same time, it is possible to determine that the external pressure corresponding to the capacity change curve with the smallest fluctuations and a larger capacity is the optimal pressure.

[0014] The curve with a larger capacity and smaller fluctuations is: a curve with a capacity decay relative to the nominal capacity within 5% and a capacity change amount of each cycle controlled within 1%.

[0015] Further, the battery is at least one of a lithium battery, a lithium-ion hybrid capacitor, a solid-state battery, and a sodium-ion battery; the different types refer to different raw materials for synthesizing the battery.

[0016] Further, the intelligent algorithm model is at least one of a neural network model, a regression model, etc.

[0017] In a second aspect, the present invention provides a method for optimizing the electrochemical performance of a battery by external pressure. By introducing an external pressure control device during the battery cycling process, the external pressure is precisely applied according to the working state of the battery, thereby improving the ionic conductivity of the battery, reducing the internal impedance of the battery, and enhancing the cycle stability and capacity of the battery.

[0018] In a third aspect, the present invention provides an experimental platform for implementing the optimization method. The experimental platform includes a constant-temperature explosion-proof box, a pressure acquisition card, a paperless recorder, a host computer, a battery test system, a thin-film pressure sensor, and a metal fixture. A thin-film pressure sensor is attached to the surface of the battery to be tested, and then the battery with the attached thin-film pressure sensor is fixed at the central position of the metal fixture. The metal fixture holds the battery without affecting the testing of the mechanical and electrochemical properties of the battery; the thin-film pressure sensor is electrically connected to the pressure acquisition card, the battery to be tested is electrically connected to the battery test system, the pressure acquisition card communicates with the host computer through the paperless recorder, and the battery test system also communicates with the host computer; the metal fixture is placed in the constant-temperature explosion-proof box; the metal fixture is connected to an external pressure device capable of uniformly applying an external pressure to the battery, and the external pressure device communicates with the host computer, and the display of the host computer can display the surface pressure value.

[0019] The battery test system can test the voltage, internal resistance, and capacity of the battery, and can also provide different current and voltage environments to simulate the working state of the battery in actual use; the pressure acquisition card is used to collect the surface pressure data of each cycle of the battery in real time through the thin-film pressure sensor.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] Scope of application: The present invention is applicable not only to lithium batteries but also to lithium-ion hybrids, and also to other types of batteries such as solid-state batteries and sodium-ion batteries. Whether in the fields of consumer electronics, energy storage devices, or electric vehicles, the technical solution of the present invention can be adopted to improve the performance and service life of the battery.

[0022] The present invention adopts pressure regulation to obtain the optimal pressure range, and can ensure that the pressure applied to the battery during battery use is maintained within the optimal pressure range. Appropriate pressure can not only effectively improve the capacity of lithium batteries, but also delay the attenuation of battery capacity during long-term use, thereby improving the cycle life of the battery.

[0023] By optimizing the pressure, the present invention enables the materials of the battery to better exert their maximum capacity, thereby improving the overall energy density of the battery. The present invention can maintain a reasonable pressure and enable the battery to maintain a high-capacity output during each charge and discharge process. Compared with the situation of rapid capacity decay or unstable performance that may occur in the prior art, the technology of the present invention has significant advantages.

[0024] The present invention uses external pressure to regulate the process of lithium batteries, thereby improving the capacity, cycle life, and safety of lithium batteries, and is applicable to the application of various lithium batteries and lithium-ion hybrids in the fields of consumer electronics, electric vehicles, energy storage devices, etc. Description of the Drawings

[0025] Figure 1 It is a schematic structural diagram of an experimental platform of an embodiment of the present invention.

[0026] Figure 2 It is a capacity comparison diagram of optimizing the performance of a lithium battery by external pressure in an embodiment of the present invention.

[0027] Figure 3 It is a surface pressure diagram of optimizing the performance of a lithium battery by external pressure in an embodiment of the present invention.

[0028] Figure 4 It is an impedance comparison diagram of optimizing the performance of a lithium battery by external pressure in an embodiment of the present invention.

[0029] In the figure, 1 is a pressure acquisition card, 2 is a paperless recorder, 3 is a host computer, 4 is a battery test system, 5 is a constant temperature explosion-proof box, 6 is a metal fixture, 7 is a thin film pressure sensor, and 8 is a battery. Detailed Embodiments

[0030] The present invention will be further described below in conjunction with the drawings and embodiments, but the scope claimed by the present invention is not limited to the scope described in the embodiments.

[0031] A method for optimizing the electrochemical performance of a lithium battery and a lithium-ion hybrid battery by external pressure according to the present invention can accurately apply external pressure according to the working state of the battery by introducing an external pressure control device during the lithium battery cycle; within a certain range, the application of external pressure helps to improve the ionic conductivity of the battery, reduce the internal impedance of the battery, and thus improve the capacity and charge-discharge efficiency of the battery; the selection of the pressure value is based on specific requirements such as battery type and electrode material, and the electrochemical performance of the lithium battery can be optimized by adjusting the pressure magnitude.

[0032] Preferably, prepare several soft-pack batteries, which must be brand-new batteries that have just completed the formation process and have been aged. The formation process refers to forming a stable electrochemical reaction structure by initially charging the battery to ensure the normal use performance of the battery.

[0033] Further, place the prepared batteries in a battery fixture that can apply pressure. The fixture is designed to be able to apply external pressure evenly and allow adjustment at different charge-discharge stages.

[0034] Further, attach a thin film pressure sensor to the surface of the battery. The thin film pressure sensor is connected to a display through a signal transmission line to display the pressure value received by the battery in real time.

[0035] Preferably, the battery is connected to a battery test system through a wire for charge and discharge operations. The test system can provide different current and voltage environments to simulate the working state of the battery in actual use. The battery test system can charge and discharge according to a set cycle mode, and during the process, the thin-film pressure sensor will continuously monitor the change in the surface pressure borne by the battery.

[0036] Furthermore, set an initial pressure value, adjust the pressurizing device so that the display shows the initial pressure value. After the initial pressure value is stable, start the battery test system to perform charge and discharge operations on the battery. The set value of the external pressure is the initial value, and different pressure values can be selected as the initial value. Under an appropriate initial pressure, it helps to improve the ionic conductivity of the battery, reduce the internal impedance of the battery, and thus enhance the capacity and charge-discharge efficiency of the battery.

[0037] The present invention can adjust the externally applied pressure in real time according to the actual working state of the battery, and can adjust the external pressure to the optimal pressure so that the battery is in the optimal performance state. Using the intelligent algorithm model can ensure that the pressure applied to the battery is maintained within the optimal pressure range, thereby delaying the attenuation of the battery capacity and increasing the cycle life of the battery.

[0038] Example 1

[0039] This example aims to explore the effects of different initial pressures on the capacity, stability and battery impedance change of a soft-pack lithium battery, providing experimental data support for optimizing the battery performance.

[0040] The method for optimizing the electrochemical performance of a lithium battery and a lithium-ion battery hybrid by external pressure includes the following steps:

[0041] Select 7 soft-pack batteries with a nominal capacity of 2000 mAh. In this example, ternary lithium-ion batteries are used, and each battery is made in the same batch to ensure performance consistency.

[0042] Control group: Do not apply an initial pressure of 0 N;

[0043] Experimental group 1: Apply an initial pressure of 40 N;

[0044] Experimental group 2: Apply an initial pressure of 60 N;

[0045] Experimental group 3: Apply an initial pressure of 80 N;

[0046] Experimental group 4: Apply an initial pressure of 100 N;

[0047] Experimental group 5: Apply an initial pressure of 120 N;

[0048] Experimental group 6: Apply an initial pressure of 140 N;

[0049] All battery samples were tested through 130 charge-discharge cycles under the charge-discharge conditions of conventional 1C charging and 1C discharging modes, and the above-set initial pressure was applied during the charge-discharge cycle test. After each cycle ended, the capacity of the battery and the change in surface pressure were recorded.

[0050] As Figure 2 shown, when an initial pressure of 60 N was applied, the capacity attenuation of the battery was the smallest and the cycle performance was the best. After 130 cycles, the battery had the smallest capacity loss and showed good stability. In contrast, the battery with an initial pressure of 140 N showed significant capacity attenuation during the cycle and had a relatively serious capacity loss, indicating that too high an initial pressure may have a negative impact on the performance of the battery. In this embodiment, the optimal pressure range is preferably 40 - 80 N, the optimal pressure is 60 N, and the number of charge-discharge cycle test turns is 130.

[0051] As Figure 3 shown, it is the real-time acquisition data of the surface pressure of the battery for each cycle during the charge-discharge cycle test when an initial pressure of 60 N was applied, achieving precise acquisition.

[0052] As Figure 4 shown, it is a comparison chart of impedance changes between applying an external initial pressure of 60 N and the control group without applying an external pressure. Figure 4 In it, the arc radius decreases under the application of an external initial pressure, indicating that the ion migration rate is fast and the internal resistance of the battery decreases. The decrease in the internal resistance of the battery shows that applying an appropriate pressure can improve the ion conductivity of the battery and enhance the charge-discharge efficiency of the battery.

[0053] Example 2

[0054] The experimental platform of this embodiment, as Figure 1 shown, the experimental platform includes a constant temperature explosion-proof box 5, a pressure acquisition card 1, a paperless recorder 2, a host computer 3, a battery test system 4, a thin film pressure sensor 7, and a metal fixture 6. A thin film pressure sensor is attached to the surface of the soft-pack battery to be tested, and then the soft-pack battery with the attached thin film pressure sensor is fixed at the center position of the metal fixture. The clamping of the metal fixture does not affect the mechanical performance and electrochemical performance tests of the soft-pack battery. The thin film pressure sensor is electrically connected to the pressure acquisition card, the soft-pack battery to be tested is electrically connected to the battery test system, the pressure acquisition card communicates with the host computer through the paperless recorder, and the battery test system also communicates with the host computer; the metal fixture is placed in the constant temperature explosion-proof box. The metal fixture is connected to an external pressurizing device and can uniformly apply an external pressure to the battery 8. The pressurizing device communicates with the host computer, and the display of the host computer can display the pressure value.

[0055] During the experiment, first, the thin-film pressure sensor was precisely attached to the surface of the soft-pack battery to ensure that it could monitor the battery pressure changes in real time. Then, the battery was placed at the center of the metal fixture to fix the battery and prevent it from displacing during the experiment. Next, the battery test system was docked with the battery through the connection interface to complete the charge and discharge tests of the battery. To ensure the safety and stability of the battery during the test, the battery was placed in a constant-temperature explosion-proof box, which had an explosion-proof function. This could not only provide a suitable temperature environment but also effectively prevent possible dangerous situations. Next, the pressure acquisition card was connected to the thin-film pressure sensor to collect pressure data in real time. At the same time, the paperless recorder was connected to the pressure acquisition card to ensure that all data during the test could be accurately recorded. The battery test system and the paperless recorder were controlled by the upper computer, which could conveniently adjust the test parameters and monitor the experimental data in real time, providing data support for subsequent analysis and processing.

[0056] Example 3

[0057] In this example, the battery structure of the lithium battery was adjusted by applying a certain external pressure to improve its electrochemical performance, enhance the battery's capacity, cycle stability, and safety. The lithium battery was placed in the metal fixture of the pressurizing device, and a certain external pressure was applied to the battery by precisely controlling the pressurizing device; while applying pressure, a charge and discharge cycle test was carried out on the lithium battery, and electrochemical parameters such as the pressure, voltage, capacity, and internal resistance of the battery were monitored in real time; by comparing the changes in battery performance under different external pressures, the optimal pressure range was determined. The present invention can effectively optimize the cycle performance of lithium batteries and lithium-ion hybrid capacitors, reduce the capacity attenuation of the battery, and improve its safety. It has significant technical advantages and application prospects, and is particularly suitable for the development and application of high-energy-density lithium batteries and lithium-ion hybrid capacitors.

[0058] Example 4

[0059] The process of the optimization method in this example is as follows: Obtain batteries processed by formation processes with different nominal capacity sizes and different types;

[0060] Gradually apply external pressure to each battery during the battery cycle to obtain the change curve of the capacity with the battery cycle under different external pressures, find the external pressure value corresponding to the curve with a larger capacity and smaller fluctuations, and obtain the optimal pressure range and optimal pressure for this type of battery;

[0061] Each type of battery corresponds to an optimal pressure range, and all types of batteries and their corresponding optimal pressure ranges form an optimization database;

[0062] Train the intelligent algorithm model with the optimization database. The input of the intelligent algorithm model is the nominal capacity and battery type, and the output is the optimal pressure range;

[0063] Input the nominal capacity and battery type of the battery to be optimized into the trained intelligent algorithm model to determine the optimal pressure range of the battery to be optimized, and apply an external pressure within the optimal pressure range to the battery to be optimized to promote the migration of ions inside the battery, so as to optimize the high battery capacity and cycle life of the battery.

[0064] The intelligent algorithm model is loaded in the host computer. According to the input parameters of the battery to be optimized, its optimal pressure range can be determined, and the optimal pressure value can also be determined. The host computer feeds back to the external pressure applying device to apply an initial pressure to the battery with the optimal pressure value to complete the charge and discharge cycle test of the battery, so as to optimize its electrochemical performance.

[0065] For any person skilled in the art, without departing from the scope of the technical solution of the present invention, many possible changes and modifications can be made to the technical solution of the present invention by using the technical content disclosed above, or it can be modified into an equivalent embodiment with equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall still fall within the scope of protection of the technical solution of the present invention. Finally, the scope of protection of the patent of this application shall be subject to the appended claims.

[0066] Matters not described in the present invention are applicable to the prior art.

Claims

1. A method for optimizing the electrochemical performance of a battery by applying external pressure, characterized in that: The method comprises the following: Obtain batteries with different nominal capacities and different types of formation processes; Gradually apply external pressure to each battery during the battery cycle process, obtain the capacity change curve under different external pressures during the battery cycle process, find the external pressure value corresponding to the curve with larger capacity and smaller fluctuation, and obtain the optimal pressure range and optimal pressure of the battery; Each type of battery corresponds to an optimal pressure range, and all types of batteries and their corresponding optimal pressure ranges constitute an optimization database; An intelligent algorithm model is trained with an optimized database, wherein the input of the intelligent algorithm model is the nominal capacity and the battery type, and the output is the optimal pressure range; The nominal capacity and battery type of the battery to be optimized are input into the trained intelligent algorithm model to determine the optimal pressure range of the battery to be optimized. External pressure within the optimal pressure range is applied to the battery to be optimized to promote the migration of ions inside the battery and optimize the battery's high battery capacity and cycle life.

2. The optimization method according to claim 1, characterized in that: The capacity decay threshold and the capacity change threshold are set. If the capacity value of each cycle in the battery cycle is not less than the capacity decay threshold, and the capacity change of each cycle is not greater than the capacity change threshold, then the external pressure value is within the optimal pressure range, otherwise it is not within the optimal pressure range; at the same time, the external pressure corresponding to the capacity change curve with the smallest fluctuation and the largest capacity can be determined as the optimal pressure.

3. The optimization method according to claim 2, characterized in that: The curve with larger capacity and smaller fluctuation is a curve in which the capacity decay relative to the nominal capacity is within 5%, and the capacity change per cycle is controlled within 1%.

4. The optimization method according to claim 1, characterized in that: The battery is at least one of a lithium battery, a lithium-ion hybrid capacitor, a solid-state battery, and a sodium-ion battery; the different types refer to different raw materials for synthesizing the battery.

5. The optimization method according to claim 1, characterized in that: The intelligent algorithm model is at least one of a neural network model and a regression model.

6. A method for optimizing the electrochemical performance of a battery by applying external pressure, characterized in that: By introducing an external pressure control device during the battery cycle process, external pressure can be accurately applied according to the working state of the battery, thereby improving the battery's ionic conductivity, reducing the battery's internal impedance, and improving the battery's cycle stability and capacity.

7. The method according to claim 6, wherein: The range of external pressure applied is based on the specific requirements of the battery type and electrode material, and the magnitude of the external pressure is adjusted to optimize the electrochemical performance of the battery.

8. An experimental platform for executing the optimization method according to any one of claims 1 to 7, characterized in that: The experimental platform includes a constant temperature explosion-proof box, a pressure acquisition card, a paperless recorder, a host computer, a battery testing system, a thin film pressure sensor and a metal clamp. The thin film pressure sensor is attached to the surface of the battery to be tested, and then the battery with the thin film pressure sensor attached is fixed at the center of the metal clamp. The clamping of the metal clamp does not affect the test of the mechanical properties and electrochemical properties of the battery; the thin film pressure sensor is electrically connected to the pressure acquisition card, the battery to be tested is electrically connected to the battery testing system, the pressure acquisition card communicates with the host computer through the paperless recorder, and the battery testing system also communicates with the host computer; the metal clamp is placed in the constant temperature explosion-proof box; the metal clamp is connected to an external pressurizing device, which can evenly apply external pressure to the battery, the external pressurizing device communicates with the host computer, and the display of the host computer can display the surface pressure value.

9. The experimental platform according to claim 8, characterized in that: The battery testing system can test the voltage, internal resistance and capacity of the battery, and can also provide different current and voltage environments to simulate the working state of the battery in actual use; the pressure acquisition card is used to collect the surface pressure data of each cycle of the battery in real time through a thin film pressure sensor.

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