Device and method for regulating and controlling pressure of solid-state battery through isostatic pressing

Abstract

The invention discloses a device and method for regulating and controlling the pressure of a solid-state battery through isostatic pressing, and belongs to the technical field of power batteries for new energy vehicles. The device comprises a gas compression cavity, wherein a piston rod is mounted in each cavity body of the gas compression cavity in a matched manner; a ventilation flange is fixed to the upper end of the gas compression cavity, a battery mounting plate is fixed to the upper end of the ventilation flange, a plurality of battery cavities corresponding to the cavities are formed in the battery mounting plate, and solid-state batteries are placed in the battery mounting plate; the ventilation flange is conducted with the battery mounting plate; a ventilation cover plate is arranged above the battery mounting plate to block the top of the battery cavity; a control circuit unit and a driving motor are installed at the bottom of the rack shell, the control circuit unit controls the speed and torque of the driving motor, and the torque of the driving motor can be transmitted to the piston rod through a torque transmission unit; a pressure sensor is arranged on the ventilation cover plate to monitor the pressure in the battery cavity and feed back pressure data as an input signal to the control circuit unit so as to adjust the torque of the driving motor.

Description

Technical Field

[0001] The present invention belongs to the technical field of power batteries for new energy vehicles, and specifically relates to a device and method for isostatically controlling the pressure of a solid-state battery. Background Art

[0002] All-solid-state batteries are considered to be a strong candidate for the next generation of energy storage technology due to their high energy density and high safety. Inside an all-solid-state battery, all interfaces are solid-solid contacts. Due to the lack of infiltration of liquid electrolyte, interface stability problems are prone to occur. These problems lead to increased interface impedance, reduced lithium ion transmission efficiency, and capacity attenuation, becoming a bottleneck on the road to commercialization of all-solid-state batteries. Studies have shown that applying appropriate stacking pressure to all-solid-state batteries is crucial to ensure the interface contact between the components inside the all-solid-state battery, and ultimately improve battery performance under actual operating conditions. In addition, the commercialization of all-solid-state lithium metal batteries requires the application of lower stacking pressure in actual operation. Excessive stacking pressure may destroy the structural integrity of the component materials and even reduce battery performance. However, conventional uniaxial battery fixtures face some challenges, especially in adapting to electrode volume changes, providing uniform pressure distribution, and maintaining consistent pressure for a long time. Existing fixture designs cannot meet the needs of precise and stable pressure control in battery research to a certain extent. In addition, the rubber and spring materials used in conventional fixtures may be susceptible to material fatigue, which means that the applied force may gradually decrease over time, affecting the performance and test results of the battery. To this end, a device for isostatic pressure regulation of solid-state battery pressure is proposed. Summary of the invention

[0003] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a device and method for isostatically controlling the pressure of solid-state batteries, which solves the problems in the prior art.

[0004] The purpose of the present invention can be achieved through the following technical solutions:

[0005] A device for isostatically regulating the pressure of a solid-state battery comprises a frame shell, a gas compression chamber is arranged on the frame shell, the gas compression chamber comprises a plurality of cavities, and a piston rod is installed in each cavity; a vent flange is fixed to the upper end of the gas compression chamber, a battery mounting plate is fixed to the upper end of the vent flange, a plurality of battery cavities corresponding to the cavities are arranged in the battery mounting plate, and solid-state batteries are placed therein; through holes are provided on the vent flange and the battery mounting plate, and are connected; a ventilation cover is arranged above the battery mounting plate, and can block the top of the battery cavity;

[0006] A control circuit unit and a drive motor are installed at the bottom of the frame housing. The control circuit unit encapsulates an inverter and a rectifier for controlling the speed and torque of the drive motor. A torque transmission unit is installed on the frame housing to transmit the torque of the drive motor to the piston rod and drive the piston tube to rise and fall.

[0007] A pressure sensor is provided on the ventilation cover to monitor the pressure inside the battery cavity and feed back the pressure data as an input signal to the control circuit unit to adjust the torque of the drive motor.

[0008] Furthermore, the ventilation cover is fastened to the ventilation flange and the battery mounting plate by locking bolts.

[0009] Furthermore, a cooling unit is provided at the upper end of the battery mounting plate. The cooling unit includes an annular cooling water channel and a plurality of cooling fins which are arranged on the battery mounting plate and are evenly distributed circumferentially. The cooling water channel runs through the plurality of cooling fins to take away the heat generated when the solid-state battery is working.

[0010] Furthermore, the outer side of the solid-state battery is wrapped with an aluminum-plastic film.

[0011] Furthermore, a compression spring is arranged between the ventilation cover and the battery mounting plate, the compression spring is sleeved on the outside of the locking bolt, and two ends of the compression spring are in contact with the ventilation cover and the battery mounting plate respectively.

[0012] Furthermore, the ventilation flange and each of the cavities are of inlay design.

[0013] Furthermore, the number of the battery cavities and the number of the cavity bodies are both 6.

[0014] Furthermore, the control circuit unit encapsulates ANN to directly perform torque control, and the control process is:

[0015] First, the pressure data fed back by the pressure sensor is converted into the target torque and actual torque required by the drive motor;

[0016] Then, the error between the target torque and the actual torque required in the battery cavity is calculated. After the rotor flux and the stator flux are estimated using ANN, the calculated torque error and flux error are input into ANN to obtain the control signal.

[0017] Finally, the actual torque and flux of the drive motor are fed back to the control circuit unit for error calculation, thereby achieving real-time pressure control.

[0018] Furthermore, the torque transmission unit includes an intermediate gear, a gear pair, a concave roller and a rack; a driving gear is fixed on the driving shaft of the driving motor and meshes with the intermediate gear, the intermediate gear meshes with a gear pair composed of different numbers of teeth, the number of teeth of the intermediate gear is greater than that of the driving gear, the number of teeth at the large end of the gear pair is greater than that of the intermediate gear, the small end is meshed with the rack, and the torque is amplified by different gear ratios; the bottom end of the piston rod is fixedly connected to the rack, and the concave roller cooperates with the convex rod on the outside of the rack.

[0019] A method for isostatic pressure regulation of solid-state battery pressure, using the above-mentioned device for isostatic pressure regulation of solid-state battery pressure, comprises the following steps:

[0020] S1, converts the pressure data fed back by the pressure sensor into the target torque and actual torque required by the drive motor;

[0021] S2, calculating the error between the target torque required in the battery cavity and the actual torque;

[0022] S3, using ANN to estimate the rotor flux and stator flux;

[0023] S4, calculating torque error and flux error;

[0024] S5, input the torque error and flux error into the ANN to obtain the control signal;

[0025] S6, performing space vector modulation according to the control signal to generate a switching signal of the inverter;

[0026] S7, the inverter generates corresponding voltage and current according to the switching signal to drive the drive motor;

[0027] S8, the rectifier converts the AC power into DC power and supplies it to the DC bus;

[0028] S9, the actual torque and magnetic flux of the driving motor are fed back to the control circuit unit for error calculation; the control circuit unit continuously cycles to achieve real-time pressure control.

[0029] Beneficial effects of the present invention:

[0030] 1. The battery pressure control device is different from the traditional uniaxial clamp. It uses gas as the pressurizing medium to achieve uniform pressure on the battery in all directions at 360 degrees.

[0031] 2. The device is designed with multiple battery cavities, each of which works independently and can accommodate different types of batteries. The circuit system can better realize battery pressure regulation under different working conditions at the same time.

[0032] 3. By constructing ANN-based direct torque control, the torque required for the motor to adapt to the pressure inside the battery cavity is obtained, which is more robust than the traditional motor torque control system.

[0033] 4. The battery will generate heat during use. The device uses a combination of cooling plates and water cooling. Compared with natural cooling and forced air cooling, it can more efficiently control the temperature of the battery in the cavity and promptly remove the excess heat generated by the battery during operation.

[0034] 5. The transmission device of the battery device adopts a reduction gear design, which further improves the transmission torque based on the large torque of the motor, and can better push the piston to change the air pressure in the cavity.

[0035] 6. The components used in the whole device have simple structures, and some parts can be purchased directly from the market. There is no special process and the cost is low. It can achieve functional requirements at a low cost and high standard and is easy to realize mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 It is a stereoscopic diagram of the overall structure of the isostatic pressure regulating solid-state battery pressure device of the present invention;

[0038] Figure 2 It is a top view of the cavity for storing the battery and the surrounding cooling device of the present invention;

[0039] Figure 3 is a stereoscopic view of a vent flange connected to a gas compression chamber in the present invention;

[0040] Figure 4 is a three-dimensional diagram of a torque transmission unit in the present invention;

[0041] Figure 5 is a three-dimensional diagram of the pressure sensor of the present invention;

[0042] Figure 6 is a three-dimensional diagram of a solid-state battery in the present invention;

[0043] Figure 7 It is a control flow chart of the control circuit unit in the present invention.

[0044] In the figure: 1-frame housing, 2-control circuit unit, 3-torque transmission unit, 4-gas compression chamber, 5-piston rod, 6-fastening screw, 7-vent flange, 8-battery mounting plate, 9-compression spring, 10-pressure sensor, 11-ventilation cover, 12-solid-state battery, 13-cooling water channel, 14-cooling plate; 15-gear pair, 16-drive motor, 17-concave roller, 18-rack, 19-intermediate gear. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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.

[0046] Example 1

[0047] like Figures 1 to 3 As shown, a device for isostatically regulating the pressure of a solid-state battery comprises a frame shell 1, a gas compression chamber 4 is arranged on the frame shell 1, the gas compression chamber 4 comprises a plurality of cavities, and a piston rod 5 is installed in each cavity; a vent flange 7 is fixed to the upper end of the gas compression chamber 4, a battery mounting plate 8 is fixed to the upper end of the vent flange 7, a plurality of battery cavities are arranged in the battery mounting plate 8, solid-state batteries 12 are placed in the battery cavities, and the battery cavities correspond to the cavities one by one; through holes are provided on the vent flange 7 and the battery mounting plate 8 to ensure that gas can enter and exit the battery cavity when the piston rod 5 is raised or lowered; a ventilation cover plate 11 is arranged above the battery mounting plate 8, the ventilation cover plate 11 is fastened to the vent flange 7 and the battery mounting plate 8 by locking bolts 6, and the ventilation cover plate 11 can block the top of the battery cavity; by controlling the lifting and lowering of the piston rod 5, the internal pressure of the battery cavity can be adjusted, thereby adjusting the pressure on the solid-state battery;

[0048] A control circuit unit 2 and a drive motor 16 are installed at the bottom of the frame housing 1. The internal chip of the control circuit unit 2 is connected to the drive motor 16 for sending and receiving signals to control the speed and torque of the drive motor. A torque transmission unit 3 is also installed on the frame housing 1. The torque transmission unit 3 is a speed reduction mechanism that can transmit the torque of the drive motor to the piston rod 5 and drive the piston tube 5 to move up and down. The control circuit unit 2 can control the lifting speed and lifting pressure of the piston rod 5 by controlling the speed and torque of the bottom drive motor 16.

[0049] The control circuit unit 2 encapsulates an inverter and a rectifier for controlling the speed and torque of the drive motor 16 .

[0050] A plurality of pressure sensors 10 are arranged on the ventilation cover plate 11, such as Figure 5 As shown, the pressure sensor 10 can monitor the pressure inside the battery cavity; the pressure sensor 10 can sensitively respond to the pressure change in the battery cavity, and by combining with the control circuit unit 2, the pressure data in the battery cavity is used as an input signal and fed back to the chip in the control circuit unit 2 to make torque adjustment for the drive motor;

[0051] The control circuit unit 2 encapsulates an artificial neural network (ANN) to directly perform torque control. Unlike the traditional method, this method does not require a speed controller, a commutation table, and a hysteresis comparator, so it can more accurately adapt to the torque during the battery pressure cycle;

[0052] like Figure 7 As shown, the process of the control circuit unit 2 regulating the torque of the drive motor is: first, the pressure data fed back by the pressure sensor 10 is converted into the target torque and actual torque required by the drive motor; then the error between the target torque required in the battery cavity and the actual torque is calculated, and after the rotor flux and stator flux are estimated using the ANN, the calculated torque error and flux error are input into the ANN to obtain a control signal; finally, the actual torque and flux of the drive motor are fed back to the control circuit unit for error calculation, thereby realizing real-time pressure control.

[0053] In this embodiment, if Figure 4 As shown, the torque transmission unit 3 includes an intermediate gear 19, a gear pair 15, a concave roller 17 and a rack 18; a driving gear is fixed on the driving shaft of the driving motor 16 and directly meshes with the intermediate gear 19, and the intermediate gear 19 meshes with the gear pair 15 with different numbers of teeth, the number of teeth of the intermediate gear 19 is greater than that of the driving gear, and the number of teeth at the large end of the gear pair 15 is greater than that of the intermediate gear 19; the small end meshes with the rack 18, and the torque is amplified by different gear ratios; the bottom end of the piston rod 5 is fixedly connected to the rack 18, and the concave roller 17 cooperates with the convex rod on the outside of the rack 18 to achieve the role of precise guidance. Finally, under the driving action of the motor, the piston rod 5 is driven to reciprocate.

[0054] like Figure 2 As shown, a cooling unit is provided at the upper end of the battery mounting plate 8, and the cooling unit includes a ring-shaped cooling water channel 13 and a plurality of cooling fins 14 which are arranged on the battery mounting plate 8 and are evenly distributed circumferentially. The cooling water channel 13 runs through the plurality of cooling fins 14, thereby being able to take away the heat generated by the solid-state battery 12 during operation, thereby ensuring the normal operation of the battery.

[0055] In this embodiment, if Figure 6 As shown, the outside of the solid-state battery 12 is wrapped with an aluminum-plastic film.

[0056] In this embodiment, a plurality of compression springs 9 are arranged between the ventilation cover 11 and the battery mounting plate 8. The compression spring 9 is sleeved on the outside of the locking bolt 6, and the two ends of the compression spring 9 are respectively in contact with the ventilation cover 11 and the battery mounting plate 8. The compression spring 9 can balance the contact between the ventilation cover 11 and the battery cavity, and also play a certain supporting role.

[0057] In this embodiment, the vent flange 7 is inlaid with each cavity and can perfectly match the cavity mouth; the number of battery cavities and cavities is 6; the piston surface of the piston rod 5 is made of rubber material to ensure good sealing in the cavity.

[0058] Example 2

[0059] Based on the device for isostatic pressure regulation of solid-state battery pressure proposed in Example 1, in this embodiment, a method for isostatic pressure regulation of solid-state battery pressure is proposed, such as Figure 7 As shown, the following steps are included:

[0060] S1, converting the pressure signal fed back by the pressure sensor into a digital signal, determining the linear or nonlinear relationship between pressure and torque through experimental calibration, thereby obtaining the target torque and actual torque required by the drive motor;

[0061] S2, calculating the error between the target torque required in the battery cavity and the actual torque;

[0062] There is a linear relationship between pressure and torque: T = k·P + b, where T is torque, P is pressure, k and b are coefficients obtained through experimental calibration, and the error e = target torque - actual torque.

[0063] S3, using ANN nonlinear fitting capability to estimate rotor flux and stator flux from input pressure, motor current, speed, etc.;

[0064] S4, calculating torque error and flux error;

[0065] Calculate the estimated flux value Φ based on the voltage model or current model of the drive motor est , the actual magnetic flux value Φ is obtained by integrating the back electromotive force act , flux error = estimated value Φ est - Actual value Φ act .

[0066] S5, input the torque error and flux error into the ANN to obtain the control signal;

[0067] S6, performing space vector modulation according to the control signal to generate a switching signal of the inverter;

[0068] S7, the inverter generates corresponding voltage and current according to the switching signal to drive the drive motor;

[0069] S8, the rectifier converts the AC power into DC power and supplies it to the DC bus;

[0070] S9, the actual torque and magnetic flux of the driving motor are fed back to the control circuit unit 2 for error calculation; the control circuit unit 2 is continuously cycled to achieve real-time pressure control

[0071] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0072] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A device for isostatically controlling the pressure of a solid-state battery, comprising a frame housing (1), characterized in that: A gas compression chamber (4) is provided on the frame shell (1), the gas compression chamber (4) includes a plurality of cavities, each of which is fitted with a piston rod (5); a vent flange (7) is fixed to the upper end of the gas compression chamber (4), a battery mounting plate (8) is fixed to the upper end of the vent flange (7), a plurality of battery cavities corresponding to the cavities are provided in the battery mounting plate (8), and solid-state batteries (12) are placed thereon; through holes are provided on the vent flange (7) and the battery mounting plate (8), and are connected; a ventilation cover plate (11) is provided above the battery mounting plate (8), and is capable of sealing the top of the battery cavity; A control circuit unit (2) and a drive motor (16) are installed at the bottom of the frame housing (1), wherein the control circuit unit (2) encapsulates an inverter and a rectifier for controlling the speed and torque of the drive motor (16); a torque transmission unit (3) is installed on the frame housing (1) and is capable of transmitting the torque of the drive motor to the piston rod (5) and driving the piston tube (5) to move up and down; A pressure sensor (10) is provided on the ventilation cover plate (11) to monitor the pressure inside the battery cavity and feed back the pressure data as an input signal to the control circuit unit (2) to adjust the torque of the drive motor (16).

2. The device for isostatically controlling solid-state battery pressure according to claim 1, characterized in that: The ventilation cover plate (11) is fastened to the ventilation flange (7) and the battery mounting plate (8) via locking bolts (6).

3. The device for isostatically controlling solid-state battery pressure according to claim 1, characterized in that: A cooling unit is provided at the upper end of the battery mounting plate (8), the cooling unit comprising an annular cooling water path (13) and a plurality of cooling fins (14) arranged on the battery mounting plate (8) and evenly distributed in the circumferential direction, the cooling water path (13) passing through the plurality of cooling fins (14) to take away the heat generated by the solid-state battery (12) when it is working.

4. The device for isostatically controlling solid-state battery pressure according to claim 1, characterized in that: The outer side of the solid-state battery (12) is wrapped with an aluminum-plastic film.

5. The device for isostatically controlling solid-state battery pressure according to claim 1, characterized in that: A compression spring (9) is provided between the ventilation cover (11) and the battery mounting plate (8), the compression spring (9) is sleeved on the outside of the locking bolt (6), and two ends of the compression spring (9) are in contact with the ventilation cover (11) and the battery mounting plate (8) respectively.

6. The device for isostatically controlling solid-state battery pressure according to claim 1, characterized in that: The ventilation flange (7) and each cavity are inlaid.

7. The device for isostatically controlling solid-state battery pressure according to claim 1, characterized in that: The number of the battery chambers and the number of the cavity bodies are both 6.

8. The device for isostatically controlling solid-state battery pressure according to claim 1, characterized in that: The control circuit unit (2) encapsulates an ANN to directly perform torque control, and the control process is as follows: Firstly, the pressure data fed back by the pressure sensor (10) is converted into the target torque and actual torque required by the driving motor; Then, the error between the target torque and the actual torque required in the battery cavity is calculated. After the rotor flux and the stator flux are estimated using ANN, the calculated torque error and flux error are input into ANN to obtain the control signal. Finally, the actual torque and magnetic flux of the driving motor are fed back to the control circuit unit (2) for error calculation, thereby achieving real-time pressure control.

9. The device for isostatically controlling solid-state battery pressure according to claim 1, characterized in that: The torque transmission unit (3) comprises an intermediate gear (19), a gear pair (15), a concave roller (17) and a rack (18); a driving gear is fixed on the driving shaft of the driving motor (16) and meshes with the intermediate gear (19); the intermediate gear (19) meshes with the gear pair (15) composed of different numbers of teeth; the number of teeth of the intermediate gear (19) is greater than that of the driving gear; the number of teeth of the large end of the gear pair (15) is greater than that of the intermediate gear (19); the small end meshes with the rack (18), and the torque is amplified by different gear ratios; the bottom end of the piston rod (5) is fixedly connected to the rack (18); the concave roller (17) cooperates with the convex rod on the outer side of the rack (18).

10. A method for isostatic pressure regulation of solid-state battery pressure, using the device for isostatic pressure regulation of solid-state battery pressure according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1, converts the pressure data fed back by the pressure sensor into the target torque and actual torque required by the drive motor; S2, calculating the error between the target torque required in the battery cavity and the actual torque; S3, using ANN to estimate the rotor flux and stator flux; S4, calculating torque error and flux error; S5, input the torque error and flux error into the ANN to obtain the control signal; S6, performing space vector modulation according to the control signal to generate a switching signal of the inverter; S7, the inverter generates corresponding voltage and current according to the switching signal to drive the drive motor; S8, the rectifier converts the AC power into DC power and supplies it to the DC bus; S9, the actual torque and magnetic flux of the driving motor are fed back to the control circuit unit (2) for error calculation; the control circuit unit (2) continuously cycles to achieve real-time pressure control.

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