EMS-controlled special-shaped battery charging and discharging balancing method

Abstract

The invention 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 to solve the problem of unbalanced charging and discharging caused by the fact that batteries with different battery models, capacities and powers exist in existing energy storage equipment at the same time. The charging and discharging time of each battery is calculated on the basis of the existing capacity of each battery, and new charging and discharging power is distributed to each battery on the basis of the calculated charging and discharging time; therefore, the function of simultaneously starting and ending charging and discharging of the battery can be realized.

Description

Technical Field

[0001] The invention belongs to the field of battery charge and discharge balance, and in particular relates to a special-shaped battery charge and discharge balance technology. Background Art

[0002] Chemical battery energy storage has been widely used. In the energy storage system that has already deployed battery energy storage, it is necessary to add energy storage batteries. These energy storages need to be uniformly dispatched, so there will be different models, capacities and powers of the old and new batteries. If the battery is charged and discharged according to the rated power of one battery, some batteries will be discharged and some batteries will still have power. The same is true for charging. Summary of the invention

[0003] In order to solve the above technical problems, the present invention proposes an EMS-controlled special-shaped battery charge and discharge balancing method, which can realize that all battery packs are fully charged and discharged at the same time.

[0004] The technical solution adopted by the present invention is: an EMS-controlled special-shaped battery charging and discharging balancing method, comprising:

[0005] Calculate the current capacity C of each battery according to SOH and battery rated capacity n ; C n Indicates the current capacity of the nth battery;

[0006] While the system is charging:

[0007] According to C n The remaining capacity of each battery and the time T required to charge at rated power are calculated by SOC and cn ; T cn Indicates the time required to charge the remaining capacity of the nth battery at rated power;

[0008] According to the remaining capacity of each battery and T n The new charging power corresponding to each battery is calculated based on the maximum value of

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

[0010] When the system is discharged:

[0011] According to C n and SOC to calculate the time T required for each battery to discharge at rated power. fn ; T fn Indicates the time required for the current capacity of the nth battery to be discharged at rated power;

[0012] According to the current power of each battery and T fn The new discharge power corresponding to each battery is calculated based on the maximum value of

[0013] If the system discharge power required by the power grid is greater than or equal to the sum of the new discharge powers of each battery, all batteries are discharged according to their new discharge powers; 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 powers of each battery.

[0014] Beneficial effects of the present invention: The present invention calculates the time required to fully charge each battery based on its existing capacity, and calculates the new charging power of 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. Synchronous charging is achieved, with the effect of starting and ending at the same time;

[0015] The discharging process is similar, and the present invention can also achieve the effect of synchronous discharging of the batteries, starting and ending at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the present invention. DETAILED DESCRIPTION

[0017] To facilitate those skilled in the art to understand the technical content of the present invention, the present invention is further explained below with reference to the accompanying drawings.

[0018] like Figure 1 As shown in the figure, these batteries of different models, capacities and powers each correspond to a power storage converter (PCS) and a battery management system (BMS); each power storage converter (PCS) and battery management system (BMS) are connected to the energy management system (EMS) respectively; the PCS realizes the storage and release of electric energy by controlling the conduction and disconnection of the switch tube. The BMS is responsible for monitoring the battery status, temperature, current, voltage and other parameters, and adjusts the charging and discharging process in real time based on these data. The EMS monitors the status of the entire energy storage system through the network. The power grid is connected to each PCS.

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

[0020] The state of health SOH1 of battery 1 is 100%, the state of health SOH2 of battery 2 is 90%, the state of health SOH3 of battery 3 is 70%, and the state of health SOH4 of battery 4 is 50%.

[0021] The state of charge SOC1 of the battery 1 is 20%, the state of charge SOC2 of the battery 2 is 40%, the state of charge SOC3 of the battery 3 is 10%, and the state of charge SOC4 of the battery 4 is 50%.

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

[0023] The rated power P1 of PCS1 is 32kW, the rated power P2 of PCS2 is 40kW, the rated power P3 of PCS3 is 15kW, and the rated power P4 of PCS4 is 18kW.

[0024] The method of the present invention is described in detail below by taking the charging process as an example:

[0025] Step 1: EMS calculates the current capacity of each battery based on the acquired health status SOH and rated capacity of each battery;

[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: Calculate the time T required to charge all remaining capacity at rated power based on the current capacity and state of charge of each battery. cn

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

[0037] The time required for battery 2 to charge at 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 value of the charging time calculated in step 3, and this value is the maximum time required for the entire system to charge at rated power. In this embodiment, the maximum time required for charging is: T c3 =10.92h.

[0041] Step 5, calculate the charging power of the other three battery groups except the battery group corresponding to T3, specifically: calculate a new power according to the maximum value time to be fully charged. In this way, the battery group with the longest time is charged with the rated power, and the other battery groups are charged with 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 new sum of 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 , then the new charging power of each battery pack calculated in step 5 is used for charging, otherwise the new charging power of each battery pack calculated in step 5 is equal to p c_total The charging power is distributed in proportion to the battery packs. This ensures that all battery packs are fully charged at the same time.

[0047] The method of the present invention is described in detail below by taking the discharge process as an example:

[0048] Step 1: EMS calculates the current capacity of each battery based on the acquired health status SOH and rated capacity of each battery;

[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] The current charge of battery 2 is: C 23 =C 21 *(SOC2)=270*40%=108kWH

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

[0057] The current charge of battery 4 is: C 43 =C 41 *(SOC4)=60*50%=30kWH

[0058] Step 3: Calculate the time T required to discharge all the remaining power at rated power based on the current power status of each battery. fn

[0059] The time required for battery 1 to discharge at 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 of the discharge time calculated in step 3, and this value is the maximum time required for the entire system to discharge at rated power. In this embodiment, the maximum time required for discharge is: T f2 =2.7h.

[0064] Step 5, calculate the difference between T f2 In addition to the corresponding battery pack, the discharge power of the other three battery packs is specifically: a new power is calculated according to the maximum value of the discharge time. In this way, the battery pack with the longest time is discharged at the rated power, and 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 new discharge power sum 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 grid is greater than or equal to p f_total , then discharge according to the new discharge power of each battery group calculated in step 5, otherwise the new discharge power of each battery group calculated in step 5 is equal to p f_total The discharge power is distributed in proportion to the power consumption. This ensures that all battery packs are discharged at the same time.

[0070] In summary, the method of the present invention can achieve synchronous charging, starting and ending at the same time during the charging process of batteries with different models, capacities and powers; similarly, the present invention can also achieve synchronous discharging of batteries with different models, capacities and powers, starting and ending at the same time.

[0071] Those skilled in the art will appreciate that the embodiments described herein are intended to help readers understand the principles of the present invention, and should be understood that the scope of protection of the present invention is not limited to such specific statements and embodiments. For those skilled in the art, the present invention may have various changes and variations. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A charging and discharging balancing method for special-shaped batteries controlled by EMS, characterized in that: According to SOH n Calculate the current capacity C of each battery using the rated capacity of the battery n ; C n Indicates the current capacity of the nth battery; SOH n Indicates the health status of the nth battery; While the system is charging: According to C n and SOC n Calculate the remaining capacity of each battery and the time T required to charge at rated power cn ; T cn Indicates the time required to fully charge the remaining capacity of the nth battery at rated power; SOC n Indicates the ratio of the current charge of the nth battery to the total charge that can be charged; According to the remaining capacity of each battery and T cn The new charging power corresponding to each battery is calculated based on the maximum value of If the system charging power required by the power grid is greater than or equal to the sum of the new charging powers of each battery, all batteries are charged according to their new charging powers; 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 powers of each battery; When the system is discharged: According to C n and SOC n Calculate the time T required for each battery to discharge at rated power. fn ; T fn Indicates the time required for the current capacity of the nth battery to be discharged at rated power; According to the current power of each battery and T fn The new discharge power corresponding to each battery is calculated based on the maximum value of If the system discharge power required by the power grid is greater than or equal to the sum of the new discharge powers of each battery, all batteries are discharged according to their new discharge powers; 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 powers of each battery.

2. The EMS-controlled special-shaped battery charge and discharge balancing method according to claim 1, characterized in that: T cn The calculation formula is: Among them, C n *(1-SOC n ) represents the remaining capacity of the nth battery, P n Indicates the rated power corresponding to the nth battery.

3. The EMS-controlled special-shaped battery charge and discharge balancing method according to claim 1, characterized in that: T fn The calculation formula is: Among them, C n *SOC n Indicates the current power of the nth battery, P n Indicates the rated power corresponding to the nth battery.

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