Equipment and method for improving capacity of lithium ion battery

Abstract

The invention belongs to the technical field of lithium ion batteries, and particularly relates to equipment and a method for improving the capacity of a lithium ion battery. Comprising a working cavity, a working cabin cover, a pressure control system and a charging and discharging system, the working cabin cover is detachably mounted on the working cavity; a fixing assembly is mounted on the inner wall of the working cavity, and a lithium battery is mounted on the fixing assembly; the pressure control system is used for controlling the pressure and temperature in the working cavity, and the pressure control system is communicated with the interior of the working cavity through a pressure-resistant hose; a temperature controller and a pressure controller are arranged on the pressure control system; the charging and discharging system is used for charging and discharging the lithium battery; the pressure and the temperature in the working cavity are controlled through the pressure control system, then the lithium battery is charged and discharged through the charging and discharging system, and the capacity of the lithium battery is improved while the pole piece deformation condition caused by existing flat plate pressing is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium ion batteries, and in particular relates to a device and method for increasing the capacity of a lithium ion battery. Background Art

[0002] Lithium-ion batteries have achieved vigorous development in new energy electric vehicles. With the rapid expansion of application fields such as low-altitude economy, large-scale energy storage and household energy storage, the demand for lithium-ion batteries is growing rapidly, and the requirements for the electrochemical performance of lithium-ion batteries are gradually increasing. The capacity of lithium-ion batteries is one of the main indicators of their electrochemical performance, which directly determines the endurance of new energy electric vehicles, aircraft and energy storage stations.

[0003] The capacity of lithium-ion batteries is determined by active materials. Due to problems such as ion diffusion, transmission and insufficient electrolyte infiltration, it is difficult for lithium ions in active materials to fully participate in the reaction. Although the existing lithium-ion battery production will go through the hot pressing process to form the SEI film and improve the capacity release of the battery, the ordinary hot pressing process uses flat plate pressure, which still has the defects of uneven pressure, resulting in easy deformation of the pole piece and damage to the electrode structure during the charge and discharge process. Summary of the invention

[0004] In view of the above problems, the present invention proposes a device for improving the capacity of a lithium-ion battery, comprising a working chamber, a working cabin cover, a pressure control system and a charging and discharging system; the working cabin cover is detachably mounted on the working chamber; a fixing assembly is mounted on the inner wall of the working chamber, and a lithium battery is mounted on the fixing assembly;

[0005] The pressure control system is used to control the pressure and temperature inside the working cavity. The pressure control system is connected to the inside of the working cavity through a pressure-resistant hose. The pressure control system is provided with a temperature controller and a pressure controller.

[0006] The charging and discharging system is used to perform charging and discharging operations on the lithium battery;

[0007] The pressure control system and the charge and discharge system are both connected to the control terminal;

[0008] The capacity of the lithium battery can be increased by pressurizing, heating, charging and discharging the lithium battery inside the working chamber.

[0009] Furthermore, a fixing block is provided on the inner wall of the working chamber, and a No. 1 fixing hole is provided on the fixing block; a No. 2 fixing hole is provided on the working cabin cover; and fixing parts are detachably connected to the No. 1 fixing hole and the No. 2 fixing hole.

[0010] Furthermore, the fixing assembly comprises a main frame, which is fixedly mounted on the inner wall of the working chamber; a plurality of groups of spacing frames are slidably mounted on the main frame; and a plurality of the lithium batteries are respectively placed between adjacent spacing frames.

[0011] Furthermore, a high-voltage resistant connector is provided on the working cabin cover; and the charging and discharging system is connected to the lithium battery via the high-voltage resistant connector.

[0012] Furthermore, the pressure control system transports the working medium into the working cavity through a pressure-resistant hose; the working medium is insulating oil, nitrogen, air or inert gas.

[0013] Furthermore, a temperature and pressure sensor is provided on the working cabin cover, and the temperature and pressure sensor is connected to the control terminal.

[0014] Furthermore, an air relief valve and a high-pressure protection valve are provided on the working cabin cover.

[0015] Furthermore, a sealing ring is embedded on the side wall of the fixing block.

[0016] The present invention provides a method for increasing the capacity of a lithium-ion battery, based on any of the above-mentioned devices for increasing the capacity of a lithium-ion battery, and specifically comprises the following steps:

[0017] Place the lithium battery on the fixed assembly, and connect the high-voltage connector to the positive and negative electrodes of the lithium battery;

[0018] Fixing the working cabin cover on the working chamber to close the working chamber;

[0019] Use the pressure control system to set the temperature T1, pressure V1, pressure increase rate S1 and time; use the charge and discharge system to set the voltage U1, current L1 and time;

[0020] Run the pressure control system, then run the charge and discharge system;

[0021] The pressure control system maintains the temperature, pressure and time in the working chamber;

[0022] Test the capacity of lithium batteries and compare it with the initial capacity of lithium batteries.

[0023] Further, V1 is 0.1MPa-200MPa, T1 is -25℃-100℃, S1 is 0.001Mpa / s-5MPa / s, U1 is 0V-5V, and L1 is 0.001A-100A;

[0024] The pressure control system maintains the pressure change in the working chamber to be ≤1 MPa.

[0025] Beneficial Effects

[0026] The beneficial effects of the present invention compared to the prior art are as follows:

[0027] 1. This application places the lithium battery in a working chamber after the lithium battery has undergone a formation process, controls the pressure and temperature in the working chamber through a pressure control system, and then charges and discharges the lithium battery through a charge and discharge system, thereby reducing the deformation of the electrode caused by the existing flat plate press and improving the capacity of the lithium battery.

[0028] 2. The present application delivers working medium into the working chamber through a pressure control system, and the working medium transmits heating and pressurization to achieve the functional effects of pressurization, heating, pressure relief and temperature reduction in the working chamber.

[0029] 3. The present application fixes the lithium battery by means of the spacer frames on both sides. The spacer frames move on the main frame to adjust the distance between two adjacent spacer frames, so that lithium batteries of different sizes and thicknesses can be placed and fixed.

[0030] 4. The present application uses a sealing ring on the inner wall of the fixed block, and adopts an O-shaped sealing ring with wear-resistant treatment to fit tightly with the lower part of the working cabin cover, thereby further improving the sealing between the working cabin cover and the working cavity.

[0031] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 The device structure diagram in the embodiment of the present invention is shown.

[0034] Figure 2 A flow chart of a method in an embodiment of the present invention is shown.

[0035] Figure 3 A comparative curve diagram of charge and discharge in the fourth embodiment of the present invention is shown.

[0036] In the figure, 1. working chamber; 2. sealing ring; 3. fixing hole No. 1; 4. fixing assembly; 5. working cabin cover; 6. fixing hole No. 2; 7. high-pressure protection valve; 8. temperature and pressure sensor; 9. air relief valve; 10. high-pressure resistant connector; 11. charging and discharging system; 12. control terminal; 13. pressure control system; 14. temperature controller; 15. pressure controller; 16. pressure-resistant hose; 17. fixing block. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] The present application provides a device for increasing the capacity of a lithium-ion battery, comprising a working chamber 1, a working chamber cover 5, a pressure control system 13 and a charging and discharging system 11; the working chamber cover 5 is detachably mounted on the working chamber 1; a fixing assembly 4 is mounted on the inner wall of the working chamber 1, and a lithium battery is mounted on the fixing assembly 4;

[0039] The pressure control system 13 is used to control the pressure and temperature inside the working chamber 1. The pressure control system 13 is connected to the inside of the working chamber 1 through a pressure-resistant hose 16. The pressure control system 13 is provided with a temperature controller 14 and a pressure controller 15. The pressure control system 13 realizes the functions of pressurizing, heating, depressurizing and cooling the working chamber 1 through the working medium. The temperature controller 14 has heating and cooling functions to control the temperature of the working medium.

[0040] The charging and discharging system 11 is used to perform charging and discharging operations on the lithium battery;

[0041] The pressure control system 13 and the charge and discharge system 11 are both connected to the control terminal 12;

[0042] The capacity of the lithium battery is increased by pressurizing, heating, charging and discharging the lithium battery in the working chamber 1. The temperature, pressure and charging and discharging parameters of the lithium battery are jointly adjusted by the control terminal 12 to further increase the capacity of the lithium battery;

[0043] The inner wall of the working chamber 1 is provided with a fixing block 17, and a No. 1 fixing hole 3 is provided on the fixing block 17; the working chamber cover 5 is provided with a No. 2 fixing hole 6; the No. 1 fixing hole 3 and the No. 2 fixing hole 6 are detachably connected with fixing parts. The thickness between the upper end surface of the fixing block 17 and the working chamber 1 is the thickness of the upper end of the working chamber cover 5; and the thickness of the lower end surface of the fixing block 17 almost reaches the bottom of the working chamber 1, and the fixing block 17 can also be integrally formed with the working chamber 1;

[0044] The fixing assembly 4 comprises a main frame, which is fixedly mounted on the inner wall of the working chamber 1; a plurality of groups of spacing frames are slidably mounted on the main frame; and a plurality of lithium batteries are respectively placed between two adjacent spacing frames.

[0045] The working cabin cover 5 is provided with a high-voltage resistant connector 10 ; the charging and discharging system 11 is connected to the lithium battery via the high-voltage resistant connector 10 .

[0046] The pressure control system 13 delivers the working medium to the working chamber 1 through the pressure-resistant hose 16; the working medium is insulating oil, nitrogen, air or inert gas.

[0047] The working cabin cover 5 is provided with a temperature and pressure sensor 8 , which is connected to the control terminal 12 .

[0048] The working cabin cover 5 is provided with an air release valve 9 and a high-pressure protection valve 7. The air release valve 9 discharges the excess gas in the working chamber 1 before the pressure control system 13 is pressurized; when an accident occurs and the pressure inside the working chamber 1 exceeds the maximum pressure value, the high-pressure protection valve 7 timely discharges the working medium inside the working chamber 1 through the high-pressure protection valve 7.

[0049] During the implementation process, multiple groups of lithium batteries are placed on the main frame, and the lithium batteries can be selected from ternary system, lithium iron phosphate system, lithium sulfur battery system and lithium cobalt oxide system; the lithium batteries are fixed by the spacer frames on both sides, and the spacer frames are moved on the main frame to adjust the distance between two adjacent spacer frames, so that lithium batteries of different sizes and thicknesses can be placed and fixed; then the multiple wiring harnesses on the high-voltage connector 10 are connected to the positive and negative electrodes of the lithium battery, so that the charging and discharging system 11 is connected to the lithium battery; then the working cabin cover 5 is installed on the working cavity 1, and the working cabin cover 5 is fixed to the fixing block 17 of the working cavity 1 by bolts through the No. 1 fixing hole 3 and the No. 2 fixing hole 6 through the fixing parts, so as to achieve fixed sealing between the working cabin cover 5 and the working cavity 1;

[0050] Before pressurization, the excess gas inside the working chamber 1 is discharged through the pressure relief valve; the set temperature, pressure, pressure increase rate and time parameters of the pressure control system 13 are set; the voltage and current parameters of the charge and discharge system 11 are set; then the pressure control system 13 is started, and the pressure control system 13 pressurizes the inside of the working chamber 1 through the pressure-resistant hose 16, and controls the required temperature and pressure through the working medium, so that the inside of the working chamber 1 reaches the required pressure and temperature conditions; then the charge and discharge system 11 is operated to charge and discharge the lithium battery; in this process, the temperature and pressure sensor 8, that is, the temperature sensor and the pressure sensor, monitors the pressure and temperature inside the pressure-resistant Zen, and transmits the monitored temperature and pressure data to the control terminal 12, and the control terminal 12 has a display screen to display the monitoring data; the pressure control system 13 maintains the temperature and pressure in the working chamber 1 within the set time;

[0051] Compared with the traditional hot pressing formation process, the pressure on the lithium battery of the present application is changed from flat plate pressing to isostatic pressing, and the force on the lithium battery is more uniform; after the lithium battery has undergone the formation process, the lithium battery is placed in the working chamber 1, and the pressure and temperature in the working chamber 1 are controlled by the pressure control system 13, and then the lithium battery is charged and discharged by the charging and discharging system 11. The charging and discharging of the lithium battery under appropriate pressurization and heating conditions can enhance the electrolyte infiltration and promote the formation of a stable SEI film; reduce the deformation of the pole piece caused by the existing flat plate pressing while improving the capacity of the lithium battery.

[0052] The present application can be used as a substitute for the existing formation process to avoid the deformation of the pole piece caused by the flat plate pressure in the existing formation process; the present application can also be used as a subsequent process of the existing formation process to reduce the deformation of the pole piece while further improving the capacity of the lithium battery.

[0053] In one embodiment of the present invention, a sealing ring 2 is embedded on the side wall of the fixing block 17. After the working cabin cover 5 is installed in the working chamber 1, the lower part of the working cabin cover 5 is attached to the inner wall of the fixing block 17. Through the sealing ring 2 on the inner wall of the fixing block 17, the wear-resistant O-shaped sealing ring 2 is tightly attached to the lower part of the working cabin cover 5, further improving the sealing between the working cabin cover 5 and the working chamber 1;

[0054] The present application provides a method for increasing the capacity of a lithium-ion battery, based on the above-mentioned device for increasing the capacity of a lithium-ion battery, such as Figure 2 As shown, the specific steps include:

[0055] Place the lithium battery on the fixing assembly 4, and connect the high-voltage connector 10 to the positive and negative electrodes of the lithium battery;

[0056] Fixing the working cabin cover 5 on the working chamber 1 to close the working chamber 1;

[0057] Use the pressure control system 13 to set the temperature T1, pressure V1, pressure increase rate S1 and time; the charge and discharge system 11 to set the voltage U1, current L1 and time;

[0058] Run the pressure control system 13, and then run the charge and discharge system 11;

[0059] The pressure control system 13 maintains the temperature, pressure and time in the working chamber 1;

[0060] Test the capacity of lithium batteries and compare it with the initial capacity of lithium batteries.

[0061] The V1 is 0.1MPa-200MPa, T1 is -25℃-100℃, S1 is 0.001Mpa / s-5MPa / s, U1 is 0V-5V, and L1 is 0.001A-100A;

[0062] The pressure control system 13 maintains the pressure change in the working chamber 1 to be ≤1MPa. The pressure control system 13 has a real-time pressure compensation function to keep the pressure inside the working chamber 1 stable; it is used to change the interface contact in the solid-state lithium battery, promote the formation of a stable intermediate phase, and thus increase the capacity of the solid-state lithium battery;

[0063] Embodiment 1

[0064] A method for increasing the capacity of a lithium-ion battery; select five lithium batteries to be processed (battery 1, battery 2, battery 3, battery 4 and battery 5) and fix them on a fixing component 4; the five lithium batteries have all undergone a formation process and the over-discharge capacity has been measured; set the pressure of a pressure control system 13 to 60 MPa, the temperature to 40°C, and the time to 100 hours; set the charging current of a charge-discharge system 11 to 0.1C (0.2A) and the discharging current to 0.1C (0.2A); then operate the pressure control system 13, and introduce insulating oil into a working cavity 1 through a pressure-resistant hose 16, so that the inside of the working cavity 1 reaches the required pressure and temperature conditions; then operate the charge-discharge system 11 to charge and discharge the lithium battery, and perform five charge-discharge cycles (the number of charge-discharge cycles corresponds to the charge-discharge time); in this process, the required temperature, pressure and time inside the working cavity 1 must be maintained;

[0065] The capacities of the five treated lithium batteries were calibrated to obtain the capacities of the treated lithium batteries. The capacities of the five lithium batteries before and after treatment were summarized in Table 1.

[0066] Table 1

[0067] Battery 1 Battery 2 Battery 3 Battery 4 Battery 5 Capacity before treatment (Ah) 2.0582 2.0696 2.0846 2.0601 2.0629 Capacity after treatment (Ah) 2.1089 2.1264 2.1342 2.1127 2.1151

[0068] As can be seen from Table 1, the capacities of all five lithium batteries have increased.

[0069] Embodiment 2:

[0070] A method for increasing the capacity of a lithium-ion battery; three lithium batteries to be processed (battery 1, battery 2 and battery 3) are selected and placed in a working chamber and fixed on a fixing component 4; the three lithium batteries have all undergone a formation process and the over-discharge capacity is measured; the pressure of a pressure control system 13 is set to 40 MPa, the temperature is set to 25° C., and the time is 120 hours; the charging current of a charge-discharge system 11 is set to 0.05 C (50 mA), and the discharging current is set to 0.05 C (50 mA); the pressure control system 13 is then operated to make the working chamber 1 reach the required pressure and temperature conditions; the charge-discharge system 11 is then operated to charge and discharge the lithium battery, and three charge-discharge cycles are performed; in this process, the required temperature, pressure and time inside the working chamber 1 are maintained;

[0071] refer to Figure 3 , the capacity of the three processed lithium-ion batteries is calibrated, and finally the capacity of the processed lithium-ion batteries is obtained.

[0072] The capacities of the three lithium-ion batteries before and after treatment are summarized to form Table 2;

[0073] Table 2:

[0074] Battery 1 Battery 2 Battery 3 <![CDATA[Capacity before treatment (mAhg -1 )]]> 1188.62 1160.80 1078.27 <![CDATA[Processed capacity (mAhg -1 )]]> 1257.46 1230.25 1223.52

[0075] It can be seen from Table 2 that the capacities of the three lithium-ion batteries have all increased.

[0076] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A device for increasing the capacity of a lithium-ion battery, characterized in that: The invention comprises a working chamber (1), a working chamber cover (5), a pressure control system (13) and a charging and discharging system (11); the working chamber cover (5) is detachably mounted on the working chamber (1); a fixing component (4) is mounted on the inner wall of the working chamber (1), and a lithium battery is mounted on the fixing component (4); The pressure control system (13) is used to control the pressure and temperature inside the working chamber (1); the pressure control system (13) is connected to the inside of the working chamber (1) through a pressure-resistant hose (16); a temperature controller (14) and a pressure controller (15) are provided on the pressure control system (13); The charging and discharging system (11) is used to perform charging and discharging operations on the lithium battery; The pressure control system (13) and the charge and discharge system (11) are both connected to the control terminal (12); By pressurizing, heating, charging and discharging the lithium battery inside the working chamber (1), the capacity of the lithium battery can be increased.

2. The device for increasing the capacity of a lithium-ion battery according to claim 1, characterized in that: A fixing block (17) is provided on the inner wall of the working chamber (1), and a first fixing hole (3) is provided on the fixing block (17); a second fixing hole (6) is provided on the working cabin cover (5); and fixing parts are detachably connected to the first fixing hole (3) and the second fixing hole (6).

3. The device for increasing the capacity of a lithium-ion battery according to claim 2, characterized in that: The fixing assembly (4) comprises a main frame, which is fixedly mounted on the inner wall of the working chamber (1); a plurality of groups of spacing frames are slidably mounted on the main frame; and a plurality of the lithium batteries are respectively placed between adjacent spacing frames.

4. The device for increasing the capacity of a lithium-ion battery according to claim 3, characterized in that: The working cabin cover (5) is provided with a high-voltage resistant connector (10); the charging and discharging system (11) is connected to the lithium battery via the high-voltage resistant connector (10).

5. The device for increasing the capacity of a lithium-ion battery according to claim 4, characterized in that: The pressure control system (13) transports a working medium into the working chamber (1) via a pressure-resistant hose (16); the working medium is insulating oil, nitrogen, air or inert gas.

6. The device for increasing the capacity of a lithium-ion battery according to claim 5, characterized in that: The working cabin cover (5) is provided with a temperature and pressure sensor (8), and the temperature and pressure sensor (8) is connected to the control terminal (12).

7. The device for increasing the capacity of a lithium-ion battery according to claim 6, characterized in that: The working cabin cover (5) is provided with an air release valve (9) and a high-pressure protection valve (7).

8. The device for increasing the capacity of a lithium-ion battery according to claim 7, characterized in that: A sealing ring (2) is embedded on the side wall of the fixing block (17).

9. A method for increasing the capacity of a lithium-ion battery, based on the device for increasing the capacity of a lithium-ion battery as claimed in any one of claims 1 to 8, characterized in that: The specific steps include: The lithium battery is placed on the fixing assembly (4), and the high-voltage resistant connector (10) is connected to the positive and negative electrodes of the lithium battery; Fixing the working cabin cover (5) on the working chamber (1) to close the working chamber (1); The pressure control system (13) is used to set the temperature T1, the pressure V1, the pressure increase rate S1 and the time; the charge and discharge system (11) is used to set the voltage U1, the current L1 and the time; operating the pressure control system (13), and then operating the charge and discharge system (11); The pressure control system (13) maintains the temperature, pressure and time in the working chamber (1); Test the capacity of lithium batteries and compare it with the initial capacity of lithium batteries.

10. A method for increasing the capacity of a lithium-ion battery according to claim 9, characterized in that: The V1 is 0.1MPa-200MPa, T1 is -25℃-100℃, S1 is 0.001Mpa / s-5MPa / s, U1 is 0V-5V, and L1 is 0.001A-100A; The pressure control system (13) maintains the pressure change in the working chamber (1) to be ≤1 MPa.

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