EMS control type special-shaped battery charging and discharging balancing method

Abstract

The application discloses an EMS-controlled special-shaped battery charging and discharging balancing method, which is applied to the field of battery charging and discharging balancing, and aims at the problem of charging and discharging imbalance of the existing energy storage equipment with different battery models, capacities and powers. The application calculates the charging and discharging time of each battery based on the existing capacity of each battery, allocates new charging and discharging power to each battery based on the calculated charging and discharging time, and thus the function of simultaneous start and end of battery charging and discharging can be realized.

Description

Technical Field

[0001] This invention belongs to the field of battery charge-discharge balancing, and specifically relates to a charge-discharge balancing technology for irregularly shaped batteries. Background Technology

[0002] Chemical battery energy storage is already widely used. In energy storage systems where battery storage has already been deployed, it is necessary to add more storage batteries. These energy storage systems need to be uniformly managed, which means that the old batteries and the new batteries may have different models, capacities, and power ratings. If they are charged and discharged according to the rated power of a single battery, some batteries will have finished discharging while others still have power. The same applies to charging. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention proposes an EMS-controlled method for balancing the charging and discharging of heterogeneous batteries, which enables all battery packs to be fully charged and discharged simultaneously.

[0004] The technical solution adopted in this invention is: an EMS-controlled method for balancing the charging and discharging of irregularly shaped batteries, comprising:

[0005] Calculate the current capacity C of each battery based on SOH and the battery's rated capacity. n C n This represents the current capacity of the nth battery;

[0006] When the system is charging:

[0007] According to C n Calculate the time T required to charge each battery at rated power based on its remaining capacity and SOC. cn ;T cn This represents the time required to charge the remaining capacity of the nth battery at its rated power.

[0008] Based on the remaining capacity of each battery and T n The maximum value is used to calculate the new charging power corresponding to each battery.

[0009] If the system charging power required by the power grid is greater than or equal to the sum of the new charging power of each battery, then all batteries are charged according to their respective new charging power; otherwise, the charging power is allocated to each battery according to the ratio of the new charging power of each battery to the sum of the new charging power of each battery.

[0010] When the system discharges:

[0011] According to C n Calculate the time T required for each battery to discharge at its rated power based on its current charge and SOC. fn ;T fn This represents the time required for the nth battery to discharge at its rated power with its current charge.

[0012] Based on the current charge of each battery and T fn The maximum value is used to calculate the new discharge power corresponding to each battery.

[0013] If the system discharge power required by the power grid is greater than or equal to the sum of the new discharge power of each battery, then all batteries discharge according to their respective new discharge power; otherwise, the discharge power of each battery is allocated according to the ratio of the new discharge power of each battery to the sum of the new discharge power of each battery.

[0014] The beneficial effects of this invention are as follows: Based on the existing capacity of each battery, this invention calculates the full charging time for each battery and calculates the new charging power for each battery group based on the longest charging time. When the charging power required by the power grid is less than the sum of the new charging powers, charging is performed according to the new charging power ratio; when the charging power required by the power grid is greater than or equal to the sum of the new charging powers, charging is performed according to the new charging power. This achieves synchronous charging, with simultaneous start and finish.

[0015] Similarly, the discharge process can also achieve synchronous battery discharge, with the batteries starting and ending at the same time. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the present invention. Detailed Implementation

[0017] To facilitate understanding of the technical content of this invention by those skilled in the art, the following description, in conjunction with the accompanying drawings, further illustrates the invention.

[0018] like Figure 1 As shown, each battery, with different models, capacities, and power ratings, corresponds to a power storage converter (PCS) and a battery management system (BMS). Each PCS and BMS is connected to an energy management system (EMS). The PCS stores and releases electrical energy by controlling the switching on and off of transistors. The BMS monitors battery status, temperature, current, voltage, and other parameters, and adjusts the charging and discharging processes in real time based on this data. The EMS monitors the status of the entire energy storage system via a network. The power grid is connected to each PCS.

[0019] In this embodiment, four sets of batteries are included.

[0020] Battery 1 has a health status of 100% (SOH1), Battery 2 has a health status of 90% (SOH2), Battery 3 has a health status of 70% (SOH3), and Battery 4 has a health status of 50% (SOH4).

[0021] The state of charge (SOC) of battery 1 is 20%, the state of charge (SOC) of battery 2 is 40%, the state of charge (SOC) of battery 3 is 10%, and the state of charge (SOC) of battery 4 is 50%.

[0022] The rated capacity of battery 1 is 200 kWh (C1), the rated capacity of battery 2 is 300 kWh (C2), the rated capacity of battery 3 is 260 kWh (C3), and the rated capacity of battery 4 is 120 kWh (C4).

[0023] The rated power of PCS1 is 32kW, the rated power of PCS2 is 40kW, the rated power of PCS3 is 15kW, and the rated power of PCS4 is 18kW.

[0024] The method of the present invention will be described in detail below using the charging process as an example:

[0025] Step 1: EMS calculates the current capacity of each battery based on the obtained State of Health (SOH) and rated capacity.

[0026] The current capacity of battery 1 is: C 11 =SOH1*C1=200*100%=200kWH

[0027] The current capacity of battery 2 is: C 21 =SOH2*C2=300*90%=270kWH

[0028] The current capacity of battery 3 is: C 31 =SOH3*C3=260*70%=182kWH

[0029] The current capacity of battery 4 is: C 41 =SOH4*C4=120*50%=60kWH

[0030] Step 2, calculate the remaining capacity of each battery:

[0031] The remaining capacity of battery 1 is: C 12 =C 11 *(1-SOC1)=200*80%=160kWH

[0032] The remaining capacity of battery 2 is: C 22 =C 21 *(1-SOC2)=270*60%=182kWH

[0033] The remaining capacity of battery 3 is: C 32 =C 31 *(1-SOC3)=182*90%=163.8kWH

[0034] The remaining capacity of battery 4 is: C 42 =C 41 *(1-SOC4)=60*50%=30kWH

[0035] Step 3: Based on the current capacity and state of charge of each battery, calculate the time T required to charge all remaining capacity at rated power. cn

[0036] The time required for battery 1 to charge at its rated power is: T c1 =C 12 / P1=160 / 32=5h

[0037] The time required for battery 2 to charge at its rated power is: T c2 =C 22 / P2=182 / 40=4.55h

[0038] The time required for battery 3 to charge at rated power is: T c3 =C 32 / P3=163.8 / 15=10.92h

[0039] The time required for battery 4 to charge at rated power is: T c4 =C 42 / P4=30 / 18=1.67h

[0040] Step 4: Find the battery pack corresponding to the maximum charging time calculated in Step 3. This value is the maximum charging time required for the entire system at rated power. In this embodiment, the maximum charging time is: T c3 =10.92h.

[0041] Step 5: Calculate the charging power for the three battery packs other than T3. Specifically, calculate a new power based on the maximum charging time. This results in the battery pack with the longest charging time being charged at its rated power, while the other battery packs are charged at the newly calculated power.

[0042] The new charging power of battery 1 is: P 11 =C 12 / T c3 =160 / 10.92 = 14.65kW

[0043] The new charging power of battery 2 is: P 21 =C 22 / T c3 =182 / 10.92 = 16.67kW

[0044] The new charging power of battery 4 is: P 41 =C 42 / Tc3 =30 / 10.92 = 2.74kW

[0045] Step 6: Calculate the sum of the new charging power p calculated in Step 5. c_total =P 11 +P 21 +P 31 +P 41 =14.65+16.67+15+2.74=49.06kW. P 31 =P3=15kW.

[0046] Step 7, if the system charging power from the grid is greater than or equal to p c_total If the battery pack is charged, then charge it according to the new charging power calculated in step 5; otherwise, charge it according to the new charging power calculated in step 5 and p. c_total The charging power is allocated proportionally to ensure that all battery packs are fully charged simultaneously.

[0047] The method of the present invention will be described in detail below using the discharge process as an example:

[0048] Step 1: EMS calculates the current capacity of each battery based on the obtained State of Health (SOH) and rated capacity.

[0049] The current capacity of battery 1 is: C 11 =SOH1*C1=200*100%=200kWH

[0050] The current capacity of battery 2 is: C 21 =SOH2*C2=300*90%=270kWH

[0051] The current capacity of battery 3 is: C 31 =SOH3*C3=260*70%=182kWH

[0052] The current capacity of battery 4 is: C 41 =SOH4*C4=120*50%=60kWH

[0053] Step 2, calculate the remaining capacity of each battery:

[0054] The current charge of battery 1 is: C 13 =C 11 *(SOC1)=200*20%=40kWH

[0055] Battery 2 currently has the following charge: C 23 =C 21 *(SOC2)=270*40%=108kWH

[0056] The current charge level of battery 3 is: C 33 =C 31 *(SOC3)=182*10%=18.2kWH

[0057] Battery 4 currently has the following charge: C 43 =C 41 *(SOC4)=60*50%=30kWH

[0058] Step 3: Based on the current state of charge of each battery, calculate the time T required for all remaining charge to discharge at rated power. fn

[0059] The time required for battery 1 to discharge at its rated power is: T f1 =C 13 / P1=40 / 32=1.25h

[0060] The time required for battery 2 to discharge at rated power is: T f2 =C 23 / P2=108 / 40=2.7h

[0061] The time required for battery 3 to discharge at rated power is: T f3 =C 33 / P3=18.2 / 15=1.21h

[0062] The time required for battery 4 to discharge at rated power is: T f4 =C 43 / P4=30 / 18=1.67h

[0063] Step 4: Find the battery pack corresponding to the maximum value among the discharge times calculated in Step 3. This value is the maximum discharge time required for the entire system at rated power. In this embodiment, the maximum discharge time is: T f2 =2.7h.

[0064] Step 5, calculate the remainder T f2 For the battery pack not included in the corresponding battery pack, the discharge power of the other three battery packs is calculated as follows: a new power is calculated based on the maximum discharge time. This results in the battery pack with the longest discharge time being discharged at its rated power, while the other battery packs are discharged at the newly calculated power.

[0065] The new discharge power of battery 1 is: P 12 =C 13 / T f3 =40 / 2.7 = 14.81kW

[0066] The new discharge power of battery 3 is: P 32 =C 33 / T f3=18.2 / 2.7=6.74kW

[0067] The new discharge power of battery 4 is: P 42 =C 43 / T f3 =30 / 2.7 = 11.11kW

[0068] Step 6: Calculate the sum of the new discharge powers p calculated in Step 5. f_total =P 12 +P 22 +P 32 +P 42 =14.81+40+6.74+11.11=72.66kW. P 22 =P2=40kW.

[0069] Step 7, if the system discharge power required by the power grid is greater than or equal to p f_total If the discharge power is calculated according to the new discharge power of each battery pack obtained in step 5, then discharge is performed; otherwise, discharge is performed according to the new discharge power of each battery pack obtained in step 5 and p. f_total The discharge power is distributed proportionally, thus ensuring that all battery packs are discharged simultaneously.

[0070] In summary, the method of this invention can achieve synchronous charging of batteries with different models, capacities, and power, with simultaneous start and end; similarly, the method of this invention can also achieve synchronous discharging of batteries with different models, capacities, and power, with simultaneous start and end.

[0071] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the principles of the invention, and should be understood that the scope of protection of the invention is not limited to such specific statements and embodiments. Various modifications and variations can be made to the invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the scope of the claims of the invention.

Claims

1. A method for balancing the charging and discharging of irregularly shaped batteries under EMS control, characterized in that, According to SOH n Calculate the current capacity C of each battery according to its rated capacity. n C n This represents the current capacity of the nth battery; SOH n This indicates the health status of the nth battery; When the system is charging: According to C n and SOC n Calculate the time T required to charge each battery at its rated power based on its remaining capacity. cn ;T cn This represents the time required to fully charge the remaining capacity of the nth battery at its rated power. SOC n This represents the proportion of the current charge of the nth battery to the total rechargeable charge. Based on the remaining capacity of each battery and T cn The maximum value is used to calculate the new charging power corresponding to each battery. If the system charging power required by the power grid is greater than or equal to the sum of the new charging power of each battery, then all batteries are charged according to their respective new charging power; otherwise, the charging power is allocated to each battery according to the ratio of the new charging power of each battery to the sum of the new charging power of each battery. When the system discharges: According to C n and SOC n Calculate the time T required for each battery to discharge at its rated power with its current charge. fn ;T fn This represents the time required for the nth battery to discharge at its rated power with its current charge. Based on the current charge of each battery and T fn The maximum value is used to calculate the new discharge power corresponding to each battery. If the system discharge power required by the power grid is greater than or equal to the sum of the new discharge power of each battery, then all batteries discharge according to their respective new discharge power; otherwise, the discharge power of each battery is allocated according to the ratio of the new discharge power of each battery to the sum of the new discharge power of each battery.

2. The EMS-controlled charging and discharging balancing method for irregularly shaped batteries according to claim 1, characterized in that, T cn The formula for calculation is: Among them, C n *(1-SOC n P represents the remaining capacity of the nth battery. n This represents the rated power of the nth battery.

3. The EMS-controlled charging and discharging balancing method for irregularly shaped batteries according to claim 1, characterized in that, T fn The formula for calculation is: Among them, C n *SOC n P represents the current charge of the nth battery. n This represents the rated power of the nth battery.

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