On-orbit charging and discharging management method of lithium ion storage battery for low-orbit aircraft

Abstract

The invention provides an on-orbit charge and discharge management method of a lithium ion storage battery for a low-orbit aircraft, which comprises the following steps: S1, according to power requirements of the aircraft under different working conditions, carrying out a discharge test according to a superposed maximum power P1; s2, performing dQ / dV processing on the discharge curve to obtain a corresponding curve, and calculating a voltage V1 corresponding to the maximum peak; s3, taking V1 as a judgment condition of discharge termination voltage, carrying out a discharge test according to the on-orbit maximum discharge depth DoD, and obtaining the lowest charge termination voltage V2; s4, delta V is superposed on V2 to serve as the charging termination voltage of the lithium ion storage battery in the initial on-orbit stage; s5, increasing delta V on the basis of the last charging termination voltage every time the discharging termination voltage drops to V1 in the long-term circulation process; and S6, when the charging termination voltage reaches the allowable maximum charging termination voltage V, the charging termination voltage is not increased any more, and circulation is continued until the service life of the lithium ion storage battery is ended. According to the invention, the on-orbit charging and discharging mode of the lithium ion storage battery pack of the low-orbit aircraft can be effectively managed, so that the on-orbit cycle life of the lithium ion storage battery pack is prolonged.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion batteries for low Earth orbit vehicles, and particularly to an on-orbit charging and discharging management method for lithium-ion battery packs. Background Technology

[0002] Lithium-ion batteries, with their superior performance in energy density and cycle life, are widely used in aerospace, electric vehicles, and new energy fields. However, prolonged charging at excessively high final voltages can cause irreversible chemical reactions within the lithium-ion battery, impacting its cycle life. Therefore, effective on-orbit charging management can significantly extend the on-orbit cycle life of lithium-ion battery packs. The peak value of the dQ / dV discharge curve of a lithium-ion battery pack corresponds to the occurrence of electrochemical reactions. By analyzing the voltage differential dQ / dV curve of the discharge curve, the optimal voltage range for on-orbit charging and discharging of the lithium-ion battery pack can be effectively assessed, thus providing methods for on-orbit charging management of lithium-ion battery packs.

[0003] Currently, there is a lack of systematic management measures for the on-orbit charging and discharging of lithium-ion batteries used in low Earth orbit spacecraft. Simply using a fixed final charging voltage mode makes it difficult to achieve the optimal on-orbit cycle life of lithium-ion battery packs.

[0004] Therefore, a standardized on-orbit charging and discharging management method for lithium-ion battery packs is needed. Based on the actual on-orbit usage of lithium-ion battery packs, specific on-orbit charging and discharging modes should be developed to extend the on-orbit cycle life of lithium-ion battery packs. Summary of the Invention

[0005] The present invention aims to provide an on-orbit charging and discharging management method for lithium-ion batteries used in low Earth orbit vehicles. By combining the actual on-orbit usage of lithium-ion battery packs, the on-orbit charging final voltage of lithium-ion battery packs is set and adjusted, thereby extending the on-orbit cycle life of lithium-ion battery packs.

[0006] The present invention provides an on-orbit charging and discharging management method for lithium-ion batteries used in low Earth orbit vehicles, comprising:

[0007] Based on the power requirements of the aircraft under different operating conditions, discharge tests were conducted according to the superimposed maximum power P1 to obtain the discharge curve of voltage versus capacity.

[0008] The discharge curve is subjected to voltage differentiation to obtain a voltage differentiation capacity curve. The voltage V1 corresponding to the maximum peak is then determined based on the voltage differentiation capacity curve.

[0009] Using voltage V1 as the criterion for determining the discharge termination voltage, discharge tests are conducted according to the maximum depth of discharge (DoD) in orbit to obtain the lowest charging termination voltage V2.

[0010] δV is superimposed on V2 as the initial charging termination voltage for the lithium-ion battery in orbit. The lithium-ion battery undergoes charge-discharge cycles according to the discharge termination voltage and the charging termination voltage in orbit. During the cycle, whenever the discharge termination voltage drops to V1, δV is added to the previous charging termination voltage to obtain a new charging termination voltage. When the charging termination voltage reaches the maximum allowable charging termination voltage V, the charging termination voltage is no longer increased, and the charge-discharge cycle continues until the end of the lithium-ion battery's life.

[0011] Preferably, the maximum power P1 is the maximum discharge power after the superposition of different operating conditions of the spacecraft in orbit.

[0012] Preferably, the maximum discharge depth DoD is the maximum discharge depth in orbit for a low Earth orbit spacecraft mission, and it is calculated as DoD = maximum discharge capacity in orbit C1 / rated capacity of lithium-ion battery pack C0.

[0013] Preferably, the charging termination voltage V2 is the discharge initiation voltage when the discharge final voltage is V1 after the lithium-ion battery pack has reached its depth of discharge DoD.

[0014] Preferably, the superimposed voltage δV is not greater than 0.1V.

[0015] Preferably, it is not required that the value of δV be the same in each charge-discharge cycle.

[0016] Preferably, the maximum allowable charging termination voltage V is the upper limit of the on-orbit operating voltage specified for the low Earth orbit spacecraft mission.

[0017] Preferably, the maximum allowable charging termination voltage V is 4.2 × n V, where n is the number of lithium-ion battery packs connected in series.

[0018] A power controller controls the charging and discharging of an on-orbit lithium-ion battery by sending corresponding commands through the aforementioned on-orbit charging and discharging management method for lithium-ion batteries used in low-Earth orbit spacecraft.

[0019] The present invention provides an on-orbit charging and discharging management method for lithium-ion batteries used in low-Earth orbit vehicles. This method can customize specific on-orbit charging and discharging modes based on the actual on-orbit usage of lithium-ion battery packs. By effectively managing the on-orbit charging and discharging modes of lithium-ion battery packs in low-Earth orbit vehicles, the on-orbit cycle life of lithium-ion battery packs can be extended. Attached Figure Description

[0020] Figure 1 This is a flowchart of an on-orbit charging and discharging management method for lithium-ion batteries used in low-Earth orbit vehicles according to the present invention;

[0021] Figure 2 The discharge curve of a certain type of lithium-ion battery pack at its maximum on-orbit power is shown.

[0022] Figure 3 The QV curve of a certain type of lithium-ion battery pack at its maximum on-orbit power.

[0023] Figure 4 The discharge curve dQ / dV of a certain type of lithium-ion battery pack under maximum on-orbit power is processed. Detailed Implementation

[0024] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a method for on-orbit charging and discharging management of lithium-ion batteries for low-Earth orbit vehicles proposed in this invention.

[0025] Figure 1 This is a flowchart illustrating an on-orbit charging and discharging management method for a lithium-ion battery used in a low-Earth orbit spacecraft, according to the present invention. Figure 1 As shown, the technical solution of the present invention provides an on-orbit charging and discharging management method for lithium-ion batteries used in low Earth orbit vehicles, comprising the following steps:

[0026] S1. Based on the power requirements of the spacecraft under different operating conditions, conduct a discharge test according to the superimposed maximum power P1. In step S1, the maximum power P1 is the maximum discharge power of the spacecraft under different operating conditions in orbit, in W.

[0027] S2. Process the discharge curve with dQ / dV to obtain the corresponding curve, and calculate the voltage V1 corresponding to the maximum peak.

[0028] S3. Using V1 as the criterion for determining the discharge termination voltage, conduct a discharge test according to the maximum discharge depth DoD in orbit to obtain the lowest charging termination voltage V2. The maximum discharge depth DoD is the maximum discharge depth in orbit for the low Earth orbit spacecraft mission, and its calculation method is DoD = maximum discharge capacity in orbit C1 / rated capacity of lithium-ion battery pack C0. The charging termination voltage V2 is the discharge starting voltage when the lithium-ion battery pack discharges to the above-mentioned DoD depth and the final discharge voltage is V1.

[0029] S4. Add δV to V2 as the charging termination voltage for the lithium-ion battery during the initial on-orbit period; the added voltage δV is (0V, 0.1V); there is no restriction on the value of the added voltage in each charge-discharge cycle, it can be the same or different.

[0030] S5. During long-term charge-discharge cycles, whenever the discharge termination voltage drops to V1, δV is added to the previous charge termination voltage. When the charge termination voltage reaches the maximum allowable charge termination voltage, the charge termination voltage is no longer increased, and the cycle continues until the lithium-ion battery life ends.

[0031] The maximum allowable charging termination voltage V is the upper limit of the on-orbit operating voltage specified for low Earth orbit spacecraft missions, typically 4.2 × n V, where n is the number of lithium-ion battery packs connected in series.

[0032] Example

[0033] The following steps will be followed to formulate an on-orbit charging and discharging management method for lithium-ion batteries used in low Earth orbit vehicles:

[0034] Step 1: Take a 45Ah single-cell 3-parallel 9-series 135Ah lithium-ion battery pack and conduct a discharge test simulating maximum power under on-orbit conditions; the discharge curve of the lithium-ion battery pack under maximum on-orbit power is shown below. Figure 2 As shown; the QV curve of the lithium-ion battery pack at its maximum on-orbit power is as follows. Figure 3 As shown;

[0035] Step 2: Perform dQ / dV processing on the discharge curve from Step 1 to obtain the corresponding curve, such as... Figure 4 As shown, find the voltage V1 corresponding to the maximum peak, which is 32V.

[0036] Step 3: Using V1 as the criterion for determining the discharge termination voltage, conduct a discharge test according to the maximum depth of discharge in orbit of 30% DoD, and obtain the lowest charging termination voltage V2 = 34.5V.

[0037] Step 4: Add δV = 0.1V to V2 as the charging termination voltage for the lithium-ion battery during the initial on-orbit period, i.e., 34.6V.

[0038] Step 5: During the long-term cycle, whenever the discharge termination voltage drops to V1, increase δV = 0.1V, i.e. 34.7V, based on the previous charge termination voltage.

[0039] Step 6: When the charging termination voltage reaches the maximum allowable charging termination voltage of 4.2V×9=37.8V, the charging termination voltage will no longer be increased, and the cycle will continue until the lithium-ion battery life ends.

[0040] The results show that by calculating the initial value of the on-orbit charging voltage of the battery pack and managing the subsequent charging and discharging according to this method, the on-orbit cycle life of the lithium-ion battery pack can be effectively extended, which has excellent guiding significance for improving the on-orbit cycle life of lithium-ion battery packs.

[0041] The present invention provides an on-orbit charging and discharging management method for lithium-ion batteries used in low-orbit vehicles. By customizing specific on-orbit charging and discharging modes according to the actual on-orbit usage of lithium-ion battery packs, the on-orbit cycle life of lithium-ion battery packs can be effectively extended.

[0042] Furthermore, the present invention also provides a power controller, wherein the software in the power controller runs the above-described on-orbit charging and discharging management method for lithium-ion batteries used in low-Earth orbit spacecraft, and sends corresponding instructions in the charging and discharging cycle to control the charging and discharging of the on-orbit lithium-ion batteries.

[0043] 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 and their equivalents, this invention also intends to include these modifications and variations.

[0044] The parts of this invention not described in detail are common knowledge to those skilled in the art.

Claims

1. A method for on-orbit charging and discharging management of lithium-ion batteries for low-Earth orbit spacecraft, characterized in that, include: Based on the power requirements of the aircraft under different operating conditions, discharge tests were conducted according to the superimposed maximum power P1 to obtain the discharge curve of voltage versus capacity. The discharge curve is subjected to voltage differentiation to obtain a voltage differentiation capacity curve. The voltage V1 corresponding to the maximum peak is then determined based on the voltage differentiation capacity curve. Using voltage V1 as the criterion for determining the discharge termination voltage, discharge tests are conducted according to the maximum depth of discharge (DoD) in orbit to obtain the lowest charging termination voltage V2. δV is superimposed on V2 as the initial charging termination voltage for the lithium-ion battery in orbit. The lithium-ion battery undergoes charge-discharge cycles according to the discharge termination voltage and the charging termination voltage in orbit. During the cycle, whenever the discharge termination voltage drops to V1, δV is added to the previous charging termination voltage to obtain a new charging termination voltage. When the charging termination voltage reaches the maximum allowable charging termination voltage V, the charging termination voltage is no longer increased, and the charge-discharge cycle continues until the end of the lithium-ion battery's life.

2. The on-orbit charging and discharging management method for lithium-ion batteries used in low-Earth orbit spacecraft as described in claim 1, characterized in that, The maximum power P1 is the maximum discharge power of the spacecraft after superimposing different operating conditions in orbit.

3. The on-orbit charging and discharging management method for lithium-ion batteries used in low-Earth orbit spacecraft as described in claim 1, characterized in that, Maximum Discharge Depth (DoD) is the maximum on-orbit discharge depth of a low Earth orbit spacecraft mission. It is calculated as: DoD = Maximum On-orbit Discharge Capacity C1 / Rated Capacity of Lithium-ion Battery Pack C0.

4. The on-orbit charging and discharging management method for lithium-ion batteries used in low-Earth orbit spacecraft as described in claim 1, characterized in that, The charging termination voltage V2 is the discharge initiation voltage when the final discharge voltage is V1 after the lithium-ion battery pack has reached its depth of discharge (DoD).

5. The on-orbit charging and discharging management method for lithium-ion batteries used in low-Earth orbit spacecraft as described in claim 1, characterized in that, The superimposed voltage δV is no greater than 0.1V.

6. The on-orbit charging and discharging management method for lithium-ion batteries used in low-Earth orbit spacecraft as described in claim 5, characterized in that, There is no requirement that the value of δV be the same in each charge-discharge cycle.

7. The on-orbit charging and discharging management method for lithium-ion batteries used in low-Earth orbit spacecraft as described in claim 1, characterized in that, The maximum allowable charging termination voltage V is the upper limit of the on-orbit operating voltage specified for low Earth orbit spacecraft missions.

8. The on-orbit charging and discharging management method for lithium-ion batteries used in low-Earth orbit spacecraft as described in claim 7, characterized in that, The maximum allowable charging termination voltage V is 4.2 × n V, where n is the number of lithium-ion battery packs connected in series.

9. A power controller, characterized in that... The on-orbit charging and discharging management method for lithium-ion batteries used in low-orbit vehicles, as described in any one of claims 1-8, sends corresponding commands to control the charging and discharging of the on-orbit lithium-ion batteries.

Images