Collaborative energy storage type battery charging and discharging equalization circuit, system and method

Abstract

The invention discloses a collaborative energy storage type battery charging and discharging equalization circuit, system and method, and relates to the technical field of energy storage power station battery charging and discharging, the collaborative energy storage type battery charging and discharging equalization circuit comprises an NMOS tube and a capacitor C1, the drain electrode of the NMOS tube is connected with one end of the capacitor C1; the other end of the capacitor C1 is connected with the positive electrode of the battery; the grid electrode of the NMOS tube and the source electrode of the NMOS tube are both connected with the negative electrode of the battery, redundant electric quantity in the battery is stored in the capacitor C1 or the electric quantity stored in the capacitor C1 is transmitted to the battery by controlling opening and closing of the NMOS tube, and electric quantity waste during charge and discharge balance of the collaborative energy storage type battery can be avoided.

Description

Technical Field

[0001] The present application relates to the technical field of battery charging and discharging in energy storage power stations, and in particular to a coordinated energy storage battery charging and discharging balancing circuit, system and method. Background Art

[0002] As the power of energy storage power sources is increased, battery cost will be the main problem of this type of power source. During the use of the battery, a battery performance degradation process corresponding to a cooperative energy storage battery charge and discharge balancing circuit occurs. In particular, the voltage imbalance of the battery series assembly corresponding to a cooperative energy storage battery charge and discharge balancing circuit during charging and discharging may be caused by different initial states, that is, before the combination, some batteries have different charges from other batteries, resulting in different voltages of each battery in the battery series group, but it may also be due to different battery capacities, resulting in voltage differences when the same energy is charged or discharged during the charging and discharging process. The problem caused by the voltage difference is that during charging, only the high voltage can be accommodated, otherwise the high voltage will be overcharged and damaged, and during discharging, only the low voltage can be accommodated. Once the lower limit is reached, the voltage can only stop discharging. At this time, some batteries may still have undischarged energy, resulting in inconsistent charging and discharging states of the cooperative energy storage battery.

[0003] The existing cooperative energy storage battery charge and discharge balancing circuit used to balance the inconsistent charge and discharge states will waste excess power during use, so a cooperative energy storage battery charge and discharge balancing circuit that solves the problem of wasting excess power is very important. Summary of the invention

[0004] The purpose of the present application is to provide a cooperative energy storage battery charge and discharge balancing circuit, system and method, which can avoid power waste when balancing the charge and discharge of the cooperative energy storage battery.

[0005] To achieve the above objectives, this application provides the following solutions:

[0006] In a first aspect, the present application provides a coordinated energy storage battery charge and discharge balancing circuit, which is applied to a battery series group, wherein the battery series group includes a plurality of batteries connected in series, and the coordinated energy storage battery charge and discharge balancing circuit includes:

[0007] NMOS tube and capacitor C 1 , the drain of the NMOS tube and the capacitor C 1 One end of the capacitor C 1 The other end is connected to the positive electrode of the battery; the gate of the NMOS tube and the source of the NMOS tube are connected to the negative electrode of the battery, and the excess power in the battery is stored in the capacitor C by controlling the opening and closing of the NMOS tube. 1 or put capacitor C 1 The energy stored in the device is transferred to the battery.

[0008] In a second aspect, the present application provides a collaborative energy storage battery charge and discharge balancing system, comprising: a BMS battery management system and n of the above-mentioned collaborative energy storage battery charge and discharge balancing circuits;

[0009] i-th 2 The positive electrode of the battery corresponding to the coordinated energy storage battery charge and discharge balancing circuit is connected to the i-th 2 -1 The negative electrode of the battery corresponding to the coordinated energy storage battery charge and discharge equalization circuit is connected; 1<i 2 ≤n and i 2 is an even number; the i-th 1 The positive electrode of the battery corresponding to the coordinated energy storage battery charge and discharge balancing circuit is connected to the i-th 1 -1 coordinated energy storage battery charge and discharge equalization circuit corresponding to the negative electrode of the battery is connected, 1<i 1 ≤n and i 1 is an odd number; the positive electrode of the battery corresponding to the nth collaborative energy storage battery charge and discharge balancing circuit, the positive electrode of the battery corresponding to the ith collaborative energy storage battery charge and discharge balancing circuit and the negative electrode of the battery corresponding to the ith collaborative energy storage battery charge and discharge balancing circuit are all connected to the positive terminal of the battery cell connection of the BMS battery management system, 1≤i<n; the negative electrode of the battery corresponding to the nth collaborative energy storage battery charge and discharge balancing circuit is connected to the negative terminal of the battery cell connection of the BMS battery management system; the negative electrode of the battery corresponding to the nth collaborative energy storage battery charge and discharge balancing circuit and the negative electrode of the battery corresponding to the n-1th collaborative energy storage battery charge and discharge balancing circuit are all connected to the current collection terminal and the control terminal of the BMS battery management system.

[0010] In a third aspect, the present application provides a collaborative energy storage battery charge and discharge balancing method, which is applied to the collaborative energy storage battery charge and discharge balancing circuit described above. The collaborative energy storage battery charge and discharge balancing method includes:

[0011] When charging the battery series group, if the voltage difference between two adjacent batteries is greater than a set threshold, the NMOS tube in the cooperative energy storage battery charge and discharge balancing circuit corresponding to the first target battery is controlled to be turned on, until the voltage difference between the two adjacent batteries is equal to the set threshold, then the NMOS tube in the cooperative energy storage battery charge and discharge balancing circuit corresponding to the first target battery is controlled to be turned off; the first target battery is the battery with the larger voltage among the two adjacent batteries;

[0012] When the battery series group is not charging, if the voltage difference between two adjacent batteries is greater than a set threshold, the NMOS tube in the cooperative energy storage battery charge and discharge balancing circuit corresponding to the second target battery is controlled to be turned on, until the voltage difference between the two adjacent batteries is equal to the set threshold, then the NMOS tube in the cooperative energy storage battery charge and discharge balancing circuit corresponding to the second target battery is controlled to be turned off; the second target battery is the battery with the smaller voltage among the two adjacent batteries.

[0013] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0014] The present application provides a coordinated energy storage battery charge and discharge balancing circuit, system and method, which controls the capacitor C by controlling the opening and closing of the NMOS tube. 1 The connection and disconnection of the high voltage battery stores the power in the capacitor C 1 Or through the capacitor C 1 Charging the low-voltage battery and collecting the excess power through the capacitor and using it in the subsequent low-voltage battery can avoid wasting power when balancing the charge and discharge of the collaborative energy storage battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 A circuit diagram of a coordinated energy storage battery charge and discharge balancing system provided in one embodiment of the present application;

[0017] Figure 2 A coordinated energy storage battery charge and discharge balancing circuit diagram provided in one embodiment of the present application;

[0018] Figure 3 A flow chart of a collaborative energy storage battery charging and discharging balancing method provided in one embodiment of the present application. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0020] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0021] In an exemplary embodiment, Figure 2 As shown, a coordinated energy storage type battery charge and discharge balancing circuit is provided, which is applied to a battery series group, wherein the battery series group includes a plurality of batteries connected in series, and the coordinated energy storage type battery charge and discharge balancing circuit includes:

[0022] NMOS tube and capacitor C 1 , the drain of the NMOS tube and the capacitor C 1 One end of the capacitor C 1 The other end is connected to the positive electrode of the battery; the gate of the NMOS tube and the source of the NMOS tube are connected to the negative electrode of the battery, and the excess power in the battery is stored in the capacitor C by controlling the opening and closing of the NMOS tube. 1 or put capacitor C 1 The energy stored in the device is transferred to the battery.

[0023] The working principle of this circuit is as follows: the circuit will detect the battery with higher voltage in the battery. In order to avoid overcharging of the battery with higher voltage, the NMOS tube is turned on at this time, and the excess electricity is put into the capacitor. When the capacity of the battery decreases, the battery will charge and discharge too quickly. At this time, the parallel capacitor will send the stored electricity to the battery to form capacitor compensation, thereby achieving voltage balance. In addition, the capacitor can also transfer the electricity stored in the capacitor to the battery with lower voltage to achieve battery balance.

[0024] Using a resistor method to balance the inconsistent discharge state is only a stopgap measure. If the voltage imbalance is caused by different initial states, it will reach a balance after one discharge, and balanced discharge will not occur again for a considerable period of time. This energy waste is acceptable. However, if the voltage imbalance of the series battery group is caused by inconsistent battery capacity, it will cause the problem of the battery capacity of the entire energy storage system not being fully utilized during use, which is a great waste. The cooperative energy storage battery charge and discharge balancing circuit provided in this embodiment controls the capacitor C by controlling the opening and closing of the NMOS tube. 1 The connection and disconnection of the high voltage battery stores the power in the capacitor C 1 Or through the capacitor C 1 To charge the low voltage battery, through the capacitor C 1 Collecting excess electricity and using it in subsequent low-voltage batteries can avoid wasting electricity when balancing the charge and discharge of the collaborative energy storage battery, extend the service life of the battery pack, and increase the utilization efficiency of the battery pack.

[0025] In practical applications, the NMOS tube is an N-channel enhancement MOSFET transistor. It is relatively convenient to use an N-channel enhancement MOSFET transistor to control the gate. If a depletion MOSFET transistor is used, a negative gate voltage is required when turning off, which is inconvenient.

[0026] In practical applications, the cooperative energy storage battery charge and discharge equalization circuit further includes: a resistor R 1 The capacitor C 1 The other end of the resistor R 1 one end of the resistor R 1 The other end is connected to the positive electrode of the battery. In order to protect the capacitor C 1 and the battery are not affected by pulse current, set the resistor R 1 Limit the inrush current to avoid large power loss, resistor R 1 The value only needs to be a very small value of 0.1Ω~0.5Ω, because the capacitor C 1 Both NMOS tubes can withstand voltages of more than tens of V.

[0027] In practical applications, the cooperative energy storage battery charge and discharge balancing circuit also includes: a Zener diode V D ; The Zener diode V D The cathode of the diode is connected to the gate of the NMOS tube, and the Zener diode V D The positive electrode is connected to the source of the NMOS tube. The Zener diode V D It is used to protect the gate safety of the NMOS tube when it is working. As long as there is 6V-7V to ensure that the NMOS tube is fully turned on, it is enough.

[0028] In practical applications, the cooperative energy storage battery charge and discharge equalization circuit further includes: a resistor R 2 The gate of the NMOS tube and the Zener diode V D The negative electrode is connected to the resistor R 2 One end of the resistor R 2 The other end of the Zener diode V D The positive terminal of the resistor R 2 is to avoid capacitor C 1 The bleeder resistor with long-term charge storage is used to limit the Zener diode V D Current, because the Zener diode V D A breakdown conduction current of a few tenths of a milliampere is enough.

[0029] In practical applications, the cooperative energy storage battery charge and discharge equalization circuit further includes: a resistor R 3 The resistor R 3 One end of each resistor R 2one end, the gate of the NMOS tube and the Zener diode V D The negative pole of the resistor R 3 The other end of the Zener diode V D The positive terminal and the resistor R 2 The other end of the resistor R 3 Used to release the NMOS gate and store it in capacitor C 1 Since the NMOS tube does not need high-speed switching here, only a resistor R ranging from tens of kilohms to hundreds of kilohms is needed. 3 Just release the gate charge.

[0030] In practical applications, the cooperative energy storage battery charge and discharge equalization circuit further includes: a resistor R 4 The drain of the NMOS tube and the resistor R 4 One end of the resistor R 4 The other end is connected to the positive electrode of the battery and the resistor R 1 The other end of the resistor R 4 To avoid the capacitor C 1 The discharge resistor that carries the charge for a long time can have a resistance of several hundred kilo-ohms, which is equivalent to artificially generating a leakage current. If the appliance does not discharge after a period of time, it will slowly discharge the capacitor C. 1 The electricity stored in the capacitor C 1 Normal energy storage operation.

[0031] like Figure 1 As shown, the present application also provides a coordinated energy storage battery charge and discharge balancing system, including: a BMS battery management system and n coordinated energy storage battery charge and discharge balancing circuits as described above. n is the total number of batteries in the battery series group.

[0032] i-th 2 The positive electrode of the battery corresponding to the coordinated energy storage battery charge and discharge balancing circuit is connected to the i-th 2 -1 The negative electrode of the battery corresponding to the coordinated energy storage battery charge and discharge equalization circuit is connected; 1<i 2 ≤n and i 2 is an even number; the i-th 1 The positive electrode of the battery corresponding to the coordinated energy storage battery charge and discharge balancing circuit is connected to the i-th 1 -1 coordinated energy storage battery charge and discharge equalization circuit corresponding to the negative electrode of the battery is connected, 1<i 1 ≤n and i 1is an odd number; the positive electrode of the battery corresponding to the nth collaborative energy storage battery charge and discharge balancing circuit, the positive electrode of the battery corresponding to the ith collaborative energy storage battery charge and discharge balancing circuit and the negative electrode of the battery corresponding to the ith collaborative energy storage battery charge and discharge balancing circuit are all connected to the positive terminal of the battery cell connection of the BMS battery management system, 1≤i<n; the negative electrode of the battery corresponding to the nth collaborative energy storage battery charge and discharge balancing circuit is connected to the negative terminal of the battery cell connection of the BMS battery management system; the negative electrode of the battery corresponding to the nth collaborative energy storage battery charge and discharge balancing circuit and the negative electrode of the battery corresponding to the n-1th collaborative energy storage battery charge and discharge balancing circuit are all connected to the current collection terminal and the control terminal of the BMS battery management system.

[0033] In practical applications, the collaborative energy storage battery charge and discharge balancing system includes: n+1 fifth resistors, the positive electrode of the battery corresponding to the first collaborative energy storage battery charge and discharge balancing circuit is connected to the positive terminal of the battery cell connection of the BMS battery management system through the first fifth resistor; the negative electrode of the battery corresponding to the nth collaborative energy storage battery charge and discharge balancing circuit is connected to the negative terminal of the battery cell connection, the current collection terminal and the control terminal of the BMS battery management system through the n+1th resistor; the negative electrode of the battery corresponding to the i-th collaborative energy storage battery charge and discharge balancing circuit is connected to the positive terminal of the battery cell connection of the BMS battery management system through the i+1th fifth resistor; the negative electrode of the battery corresponding to the n-1th collaborative energy storage battery charge and discharge balancing circuit is connected to the current collection terminal and the control terminal of the BMS battery management system through the nth fifth resistor, and the negative electrode of the battery corresponding to the nth collaborative energy storage battery charge and discharge balancing circuit is connected to the current collection terminal and the control terminal of the BMS battery management system through the n+1th fifth resistor.

[0034] In practical applications, the collaborative energy storage battery charge and discharge balancing system also includes: n+1 second capacitors, the positive electrode of the battery corresponding to the t-th collaborative energy storage battery charge and discharge balancing circuit is connected to the negative electrode of the battery corresponding to the t-th collaborative energy storage battery charge and discharge balancing circuit through the t-th second capacitor, 1≤t≤n, and the negative electrode of the battery corresponding to the n-th collaborative energy storage battery charge and discharge balancing circuit is connected to the current collection end and the control end of the BMS battery management system through the n+1-th second capacitor.

[0035] The basic battery voltage balancing logic in the BMS battery management system is as follows: 1. Detect the voltage of each battery; 2. Detect that the battery voltage corresponding to a certain cooperative energy storage battery charge and discharge balancing circuit is too high; 3. Open the discharge circuit to discharge so that the battery reaches balance; 4. If the battery voltage corresponding to a certain cooperative energy storage battery charge and discharge balancing circuit is too high in advance during charging multiple times, and the battery voltage drops faster than other battery voltages during discharge, it can be judged that the battery capacity has decreased. The specific process is: analyze the battery voltage, and when the voltage is too high, the battery is connected to the capacitor balancing circuit, that is, the cooperative energy storage battery charge and discharge balancing circuit provided in the above embodiment. At this time, the battery stores excess electricity in the capacitor C 1 After the voltage returns to normal, disconnect the capacitor C 1 Circuit, after the battery capacity is detected to be normal, until all battery voltages reach a balance, the battery pack can be used normally; if the battery capacity detection is abnormal, the discharge efficiency of the battery is judged. If the battery capacity decreases and the temperature rise is too high, the BMS battery management system will alarm, the battery pack will quit working and be replaced with a new battery pack. If the battery capacity decreases too low and does not reach the minimum use condition of the battery, the battery parallel circuit is turned on, and the capacitor C 1 Discharge the battery.

[0036] like Figure 3 As shown, the present application also provides a collaborative energy storage battery charge and discharge balancing method, which is applied to the collaborative energy storage battery charge and discharge balancing circuit described above, and the collaborative energy storage battery charge and discharge balancing method includes:

[0037] When charging the battery series group, if the voltage difference between two adjacent batteries (which can be 0.01) is greater than a set threshold, the NMOS tube in the collaborative energy storage battery charge and discharge balancing circuit corresponding to the first target battery is controlled to be turned on, until the voltage difference between the two adjacent batteries is equal to the set threshold, then the NMOS tube in the collaborative energy storage battery charge and discharge balancing circuit corresponding to the first target battery is controlled to be turned off; the first target battery is the battery with the larger voltage among the two adjacent batteries.

[0038] When the battery series group is not charging, if the voltage difference between two adjacent batteries is greater than a set threshold, the NMOS tube in the cooperative energy storage battery charge and discharge balancing circuit corresponding to the second target battery is controlled to be turned on, until the voltage difference between the two adjacent batteries is equal to the set threshold, then the NMOS tube in the cooperative energy storage battery charge and discharge balancing circuit corresponding to the second target battery is controlled to be turned off; the second target battery is the battery with the smaller voltage among the two adjacent batteries.

[0039] In practical applications, the collaborative energy storage battery charge and discharge balancing method also includes:

[0040] For any battery corresponding to a cooperative energy storage battery charge and discharge balancing circuit in the battery series group, the capacity of the battery at the current number of times is calculated, and it is determined whether the capacity of the battery at the current number of times is within a first set interval (80%-100%) to obtain a first judgment result.

[0041] If the first judgment result is yes, it is determined that the battery is normal and can continue to be used.

[0042] If the first judgment result is no, the discharge efficiency of the battery at the current number of times is calculated, and it is determined whether the discharge efficiency of the battery at the current number of times is within a second set interval to obtain a second judgment result.

[0043] If the second judgment result is yes, and the battery has only decreased in capacity, it can continue to be used.

[0044] If the second judgment result is no, and the capacity of the battery at the current number of times is lower than that of the battery at the previous number of times, and the temperature of the battery at the current number of times is higher than that of the battery at the previous number of times, an alarm is issued, the BMS battery management system issues an alarm, and the battery stops working.

[0045] In actual applications, the balancing circuit is connected in parallel to the battery for a long time. If the battery capacity increases by 5% to 10% and then returns to normal, it can continue to be used. If it does not increase to 5% to 10%, and the problem still exists after two or three charge and discharge judgments and tests, it is judged as a battery failure, an alarm is issued, and the battery pack stops working.

[0046] In practical applications, the capacity formula is: (battery actual capacity / rated capacity)*100%, actual capacity = power / SOC. Charge and discharge rate = charge and discharge current / rated capacity.

[0047] In practical applications, the steps for calculating battery capacity are explained using lithium iron phosphate batteries as an example:

[0048] The upper limit of the charging voltage of lithium iron phosphate battery is 3.7V, the lower limit of the discharge voltage is 2.7V, and the nominal voltage is 3.2V. Based on the capacitor storing about 5% of the electrical energy, we can get: E = 5% * 3.2 * 4.8Ah = 0.768Wh = 2764J. At this time, the required capacitor capacity is: The capacitor capacity required at this time can be achieved based on the capacitor size in the current market.

[0049] In the collaborative energy storage battery charge and discharge balancing method provided in this embodiment, the basic logic is not much different from the resistance balancing method, but in terms of logic and battery capacity judgment, when it is judged that the battery capacity has decreased, the capacitor and the battery are connected to each other with a MOSFET transistor, and they charge and discharge together, which is equivalent to using a capacitor on a battery with degraded capacity, which is equivalent to using a capacitor to expand a portion of the battery capacity, and the expanded capacity depends on the size of the capacitor.

[0050] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0051] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A coordinated energy storage battery charge and discharge equalization circuit, applied to a battery series group, wherein the battery series group comprises a plurality of batteries connected in series, characterized in that: The collaborative energy storage battery charge and discharge equalization circuit comprises: An NMOS tube and a capacitor C1, wherein the drain of the NMOS tube is connected to one end of the capacitor C1; the other end of the capacitor C1 is connected to the positive electrode of the battery; the gate of the NMOS tube and the source of the NMOS tube are both connected to the negative electrode of the battery, and by controlling the opening and closing of the NMOS tube, the excess power in the battery is stored in the capacitor C1 or the power stored in the capacitor C1 is transmitted to the battery.

2. The cooperative energy storage battery charge and discharge equalization circuit according to claim 1, characterized in that: The NMOS tube is an N-channel enhancement type MOSFET transistor.

3. The cooperative energy storage battery charge and discharge equalization circuit according to claim 1, characterized in that: The cooperative energy storage battery charge and discharge equalization circuit further includes: a resistor R1; the other end of the capacitor C1 is connected to one end of the resistor R1; and the other end of the resistor R1 is connected to the positive electrode of the battery.

4. The cooperative energy storage battery charge and discharge equalization circuit according to claim 1, characterized in that: The coordinated energy storage battery charge and discharge equalization circuit also includes a Zener diode V D ; The Zener diode V D The cathode of the diode is connected to the gate of the NMOS tube, and the Zener diode V D The positive electrode is connected to the source of the NMOS tube.

5. The cooperative energy storage battery charge and discharge equalization circuit according to claim 4, characterized in that: The cooperative energy storage battery charge and discharge balancing circuit also includes: a resistor R2; a gate of the NMOS tube and a Zener diode V D The negative electrode of each of the resistors R2 is connected to one end of the resistor R2, and the other end of the resistor R2 is connected to the Zener diode V D positive connection.

6. The cooperative energy storage battery charge and discharge equalization circuit according to claim 5, characterized in that: The cooperative energy storage battery charge and discharge balancing circuit also includes: a resistor R3; one end of the resistor R3 is respectively connected to one end of the resistor R2, the gate of the NMOS tube and the Zener diode V D The other end of the resistor R3 is connected to the negative electrode of the Zener diode V D The positive electrode of and the other end of the resistor R2 are connected.

7. The cooperative energy storage battery charge and discharge equalization circuit according to claim 1, characterized in that: The cooperative energy storage battery charge and discharge balancing circuit also includes: a resistor R4; the drain of the NMOS tube is connected to one end of the resistor R4, and the other end of the resistor R4 is respectively connected to the positive electrode of the battery and the other end of the resistor R1.

8. A coordinated energy storage battery charge and discharge balancing system, characterized in that: The collaborative energy storage battery charge and discharge balancing system comprises: a BMS battery management system and n collaborative energy storage battery charge and discharge balancing circuits according to any one of claims 1 to 7 above; The positive electrode of the battery corresponding to the i2th cooperative energy storage battery charge and discharge balancing circuit is connected to the negative electrode of the battery corresponding to the i2-1th cooperative energy storage battery charge and discharge balancing circuit; 1<i2≤n and i2 is an even number; the positive electrode of the battery corresponding to the i1th cooperative energy storage battery charge and discharge balancing circuit is connected to the negative electrode of the battery corresponding to the i1-1th cooperative energy storage battery charge and discharge balancing circuit, 1<i1≤n and i1 is an odd number; the positive electrode of the battery corresponding to the nth cooperative energy storage battery charge and discharge balancing circuit and the i-th cooperative energy storage battery charge and discharge balancing circuit are connected. The positive electrode of the corresponding battery and the negative electrode of the battery corresponding to the i-th collaborative energy storage battery charge and discharge balancing circuit are both connected to the positive terminal of the battery cell connection of the BMS battery management system, 1≤i<n; the negative electrode of the battery corresponding to the n-th collaborative energy storage battery charge and discharge balancing circuit is connected to the negative terminal of the battery cell connection of the BMS battery management system; the negative electrode of the battery corresponding to the n-th collaborative energy storage battery charge and discharge balancing circuit and the negative electrode of the battery corresponding to the n-1-th collaborative energy storage battery charge and discharge balancing circuit are both connected to the current collection terminal and control terminal of the BMS battery management system.

9. A collaborative energy storage battery charge and discharge balancing method, characterized in that: The cooperative energy storage battery charge and discharge balancing circuit is applied to any one of claims 1 to 7, and the cooperative energy storage battery charge and discharge balancing method includes: When charging the battery series group, if the voltage difference between two adjacent batteries is greater than a set threshold, the NMOS tube in the cooperative energy storage battery charge and discharge balancing circuit corresponding to the first target battery is controlled to be turned on, until the voltage difference between the two adjacent batteries is equal to the set threshold, then the NMOS tube in the cooperative energy storage battery charge and discharge balancing circuit corresponding to the first target battery is controlled to be turned off; the first target battery is the battery with the larger voltage among the two adjacent batteries; When the battery series group is not charging, if the voltage difference between two adjacent batteries is greater than a set threshold, the NMOS tube in the cooperative energy storage battery charge and discharge balancing circuit corresponding to the second target battery is controlled to be turned on, until the voltage difference between the two adjacent batteries is equal to the set threshold, then the NMOS tube in the cooperative energy storage battery charge and discharge balancing circuit corresponding to the second target battery is controlled to be turned off; the second target battery is the battery with the smaller voltage among the two adjacent batteries.

10. The coordinated energy storage battery charge and discharge balancing method according to claim 9, characterized in that: The collaborative energy storage battery charge and discharge balancing method also includes: For any battery corresponding to the cooperative energy storage battery charge and discharge balancing circuit in the battery series group, calculate the capacity of the battery at the current number of times, and determine whether the capacity of the battery at the current number of times is within a first set interval to obtain a first determination result; If the first judgment result is no, calculating the discharge efficiency of the battery at the current number of times, and judging whether the discharge efficiency of the battery at the current number of times is within a second set interval, to obtain a second judgment result; If the second judgment result is no, and the capacity of the battery at the current number of times is lower than that of the battery at the previous number of times, and the temperature of the battery at the current number of times is higher than that of the battery at the previous number of times, an alarm is issued.

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