WO2019093048A1

WO2019093048A1 - Combined electricity storage system

Info

Publication number: WO2019093048A1
Application number: PCT/JP2018/037709
Authority: WO
Inventors: 井上　健士; 茂樹牧野; 大輝小松
Original assignee: 株式会社日立製作所
Priority date: 2017-11-13
Filing date: 2018-10-10
Publication date: 2019-05-16
Also published as: JP2021040354A

Abstract

This combined electricity storage system is configured by connecting a capacity battery pack and a power battery pack in parallel via a capacity battery pack switch and a power battery pack switch, wherein: when charging the combined electricity storage system, charging is started after turning on the capacity battery pack switch and the power battery pack switch; and when the current flowing through either the capacity battery pack or the power battery pack has become the discharge side, the switch of a battery pack, the current flowing through which has become the discharge side, is turned off. This can provide such a control that increases charging power as much as possible in a short time with a configuration in which the capacity battery pack and the power battery pack are in parallel.

Description

Combined storage system

The present invention is a complex system of batteries for supplying power to an electrical load.

Electric vehicles have a quick charge that shortens the charge time. This quick charge charges the battery to a charge rate of 80% in about 30 minutes of charge.

Since the current rapid charging requires as much as 30 minutes, the charging time for the driver is bothersome, which is a factor that hinders the spread of electric vehicles. Even if charging is stopped for only 5 minutes using the current rapid charger, the capacity type battery (kWh-oriented type) currently mounted on electric vehicles has a low charging C rate and at most twice the capacity [kWh]. Only charge power can be provided. A commuter electric vehicle (with a cruising distance of about 100 km after one charge) with a current capacity of 10 kWh will have a maximum charging capacity of 20 kW, and in 5 minutes it can only travel about 16.5 km with 1.65 kWh of charging energy. It can only travel about 1.65 km in one minute. In order to solve this, it is conceivable to mount more battery capacity [kWh], but the battery cost may be high, which may hinder the spread. There is also a measure to increase the charging C rate of the capacity type battery, but it takes time to solve it.

As an operation of the electric car, by charging about 10 km while parking or stopping for less than 5 minutes, even a car with a small battery capacity [kWh] can continue the navigation of the day without making the user aware of the troublesomeness of charging time In order to secure the distance, we want low cost (small installed battery capacity kWh). One possible solution is to install a battery (power type battery) with a large charging power even if the capacity is small, and earn a charge energy [kWh] that can be earned by charging for less than 5 minutes. For example, a system combining 8kWh of capacity type batteries (maximum charge rate 2C) and 2kWh of power type batteries (maximum charge rate 20C) (traveling about 100km by one charge), theoretically up to 16kW + 40kW Charge power can be received, and even if it is 1 minute charge, 0.93 kWh (about 9.3 km traveling) becomes possible. When charging for 5 minutes, the capacity kWh of the power type battery is specified, and the charging energy is 3.33 kWh, but it is still possible to travel about 33.3 km. Also, in the case of a vehicle loaded with a 24kWh capacity battery by a 1.2t car, charging is 4kWh (about 32km traveling) in the first 5 minutes and 0.8kWh (about 6.4km traveling) in the first one minute. When this vehicle is loaded with 2kWh power type batteries, it takes about 6kwh in the first 5 minutes (6kWh for power type batteries to fully charge, approximately 48km travel), 1.47kWh in the first minute (approximately 11.7km travel) It becomes charge.

However, in this example, it is the best case in which the maximum current is charged to each of the two batteries, and it is only an example in which the charger is connected to the two batteries. Connecting a charger to the two batteries is costly. Therefore, assuming a low-cost system in which two batteries are connected in parallel via a switch, consider the case of rapid charging.

When two batteries are connected in parallel, a cross current (circulating current) is generated when the potentials of the respective batteries are different. Since this cross current is likely to cause power loss, there has been a switch control patent for preventing this cross current.

JP 2012-235610 A

Patent Document 1 is a patent focusing on the prevention of circulating current (hereinafter referred to as cross current), and it is difficult to apply it to rapid charging as it is not conscious of rapid charging. This is because even if the battery potential is different, the charging current is further applied, so that the cross flow does not necessarily occur as a circuit equation.

An object of the present invention is to provide a control in which a charging power is increased as much as possible in a short time by a configuration in which a capacitive battery pack and a power battery pack are connected in parallel.

The features of the present invention for solving the above problems are, for example, as follows.

In a composite storage system in which a capacitive battery pack and a power battery pack are connected in parallel via a capacitive battery pack switch and a power battery pack switch, the capacitive battery pack switch and the power are charged when charging the composite storage system. The battery pack switch is turned on to start charging, and when the current flowing to either the capacitive battery pack or the power battery pack is on the discharge side, the composite battery switch switch off on the discharge side Power storage system.

In a complex power storage system in which a capacitive battery pack and a power battery pack are connected in parallel via a capacitive battery pack switch and a power battery pack switch, when charging the complex power storage system with a charger, current is applied to the charger side When sending the command value, estimate the current estimated value when the capacitive battery pack and the power battery pack are connected in parallel by the open circuit voltage value and DC resistance value of the capacitive battery pack and the power battery pack, If it is estimated that the current value estimation and charging of either of the battery pack and the power battery pack are made, turn on the capacity type battery pack switch and the power type battery pack switch, and set the current command value to min (Capacitive type battery pack and power type battery The sum of the pack's current estimates, the maximum charging current of the charger), and the discharge if either the capacitive battery pack or the power battery pack If the estimated current value is higher, the switch on the battery pack side that is estimated to be discharged is turned off and the charging current command value is min (maximum current value on the battery pack side to be on, (maximum voltage on the battery pack to be on The battery pack's open circuit voltage) / the battery pack's DC resistance, which is turned on.

According to the present invention, with the configuration in which the capacitive battery pack and the power battery pack are arranged in parallel, it is possible to provide such control as to increase the charging power as much as possible in a short time. Problems, configurations, and effects other than those described above will be apparent from the description of the embodiments below.

The figure of the system configuration example at the time of applying a compound electricity storage system to an electric vehicle. The block diagram of the battery part of a composite electrical storage system. Control flow diagram of switch only. The principle figure which showed the current range which becomes the maximum charge current. Control flow diagram for both current and switch.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings, but the present invention is not limited to the following embodiments, and various modifications and applications can be made within the technical concept of the present invention. Is included in the range. For example, the embodiments described below are also applicable to building management systems, ships, railways, and electric planes.

In this embodiment, when charging the composite storage system in a composite storage system in which the capacitive battery pack 22 and the power battery pack 21 are connected in parallel via the capacitive battery pack switch 24 and the power battery pack switch 23. Start charging with the capacitive battery pack switch 24 and the power battery pack switch 23 turned on, and discharge when the current flowing to either the capacitive battery pack 22 or the power battery pack 21 becomes the discharge side. The battery pack switch on the side is off. Further, in the present embodiment, in the configuration in which the capacitive battery pack 22 and the power battery pack 21 are connected in parallel to the charger via the switch and the switch is controlled by the controller, the capacitive battery pack 22 and the power battery are An ammeter is provided in the pack 21. When the polarity of each current is reversed, the switch of the battery pack to be discharged is separated. Further, in the present embodiment, the controller instructs the charger to calculate the total charging current, and the current to each battery pack is controlled to be equal to or less than the maximum C rate of the battery.

When charging an electric vehicle or the like with a conventional quick charger, a charging time of 30 minutes is required. For example, if the quick charging is stopped for about 1 minute, the vehicle can only travel for about several kilometers. In order to realize charging of up to 10 km in the first few minutes with the quick charger, the power storage battery pack 21 is connected in parallel to the conventional capacity battery pack 22 and parallel combination of switches is used for cost reduction. When considering the system, it was unclear which charging control would be the maximum charging amount in the first few minutes. On the other hand, by maximizing the charging current in the rapid charging mode, 0.93 kWh charging (about 9.3 km travel) becomes possible even if it is 1 minute by the above, and one full Even an electric car that can only travel 100 km at a charge can travel more than 100 km a day without being aware of the charging time.

FIG. 1 shows an embodiment of the present invention. FIG. 1 shows an electric vehicle 10, which includes a motor generator 11, an inverter 12, a battery unit 13, an ECU 14, a communication line 15 for exchanging information to the ECU 14 with the battery unit 13 and the inverter 12, a quick charger 16, and a charging connector 17. Configured

The electric vehicle 10 supplies electric power from the battery unit 13 to the inverter 12 and rotates by driving the motor generator 11. At the time of regeneration, the electric power generated by the motor generator 11 is rectified by the inverter and charged in the battery unit 13. Although FIG. 1 shows the same motor and generator in the motor generator 11, the motor and the generator may be separate. The quick charger 16 is connected to the electric vehicle 10 through the charging connector 17, and the power line 18 is connected to the battery unit 13. Further, the ECU 14 and the quick charger 16 are connected via the communication line 15, and the ECU 14 instructs the quick charger 16 a current command to charge the battery unit 13. Here, the quick charger 16 and the charging connector 17 may use general-purpose quick charging standards or a wireless power feeding system.

Next, the configuration of the battery unit 13 is shown in FIG. The battery unit 13 includes a power type battery pack 21, a capacity type battery pack 22 for holding a sustaining power, a power type battery pack switch 23, and a capacity type battery pack switch 24. The ECU 14 issues an on / off command of the power type battery pack switch 23 (hereinafter sometimes simply referred to as a switch) and the capacitance type battery pack switch 24 (hereinafter sometimes simply referred to as a switch) The current and voltage information of the capacitive battery pack 22 are read, and a current command value is sent to the quick charger 16. Here, although the configuration is such that the information of both the capacitive battery pack 22 and the power battery pack 21 is obtained by the ECU 14 and the switch control is performed, the controller 14 may be prepared separately from the ECU 14.

The sequence of switches will now be described. The idea here is to be able to charge the power that is the largest in the first 5 minutes or less. Further, as a constraint condition, the charging current of the capacity type battery pack 22 and the power type battery pack 21 should be less than a specified value. Here, the idea of the cross flow described in Patent Document 1 will be described. The cross current is a phenomenon in which a battery with a higher voltage is discharged to a battery with a lower battery voltage when the two battery voltages connected in parallel are not aligned. In this case, the current charged to the low battery voltage is larger than the current charged from the charger. In this case, in terms of heat loss, it means that the calorific value of the battery with low battery voltage, that is, the heat loss is higher than the charge when the battery is alone. And the battery current of low battery voltage is large, and there is also a possibility of exceeding the chargeable C rate. For this reason, when a cross current occurs, it is preferable to interrupt the switch on the battery side to be discharged in terms of charging, which is more efficient and suppresses the maximum charging current.

Next, after the switch is shut off, the connected battery is charged, the battery voltage is increased, and the battery voltage is equalized. If the battery voltages are equalized, no cross current will occur even if they are paralleled, and if the two batteries are charged, the charging power seen in total will be larger, so they will be returned in parallel. The flow of the above thought is explained in FIG.

First, in step 31 (both switch on command steps), both switches are turned on. Next, in step 32 (current measurement step), the current of the capacitive battery pack 22 and the power battery pack 21 is measured. Then, in step 33 (judgement of cross current), it is determined whether or not cross current has occurred. If cross current has not occurred, the process proceeds to step 34 (judgement of charge end). . Here, the definition of the cross current is various, but here, it is defined as "the battery pack is charged while the battery pack is charged, and the other battery is discharged". As determination of the cross flow in step 33, it is assumed that either the power battery pack 21 or the capacity battery pack 22 is discharged. Step 34 ends charging. In this charge end, it is assumed that the driver has stopped charging or is fully charged. If it is determined in step 34 that the charging has not been completed, the process proceeds to step 32. If the charging is completed, the flow of FIG. 3 is ended.

Next, at step 35 (switch-off step of the battery pack to be discharged), based on the current measured at step 32, the battery pack being discharged is switched off, and the process is transferred to step 36. In step 36 (battery current / voltage measurement step), the current and voltage of the capacitive battery pack 22 and the current and voltage of the power battery pack 21 are measured, and the process proceeds to step 37.

In step 37 (judgement of occurrence of cross current), it is determined whether or not cross current is generated when connected in parallel, and if it is determined that cross current is generated, the process is transferred to step 31; Transfer the process. The cross current judgment is made by the difference in the signs of the estimated currents ip (power type battery pack 21) and ic (capacitance type battery pack 22) when connected in parallel. From the circuit equation, ip and ic indicate the direct current resistance rp of the power type battery pack 21, the direct current resistance rc of the capacitive type battery pack 22, the open circuit voltage (with polarization) vp of the power type battery pack 21 and the open type of the capacitive type battery pack 22 It is calculated as Expression 1 from voltage (polarization included) vc.

R = rc × rp / (rc + rp), Vb = (rc × vp + rp × vc) / (rp + rc)
Ic = (Vb-Vc) / rc, Ip = (Vb-Vp) / rc (Equation 1)
Here, rc and rp may be stored in advance in a table or may be values estimated from the current / voltage difference at the previous switch off timing. Since vp and vc are open circuit voltages (including polarization), they may be calculated from the terminal voltage as current × DC resistance.

Next, it is judged at step 38 (judgement of charge end) whether or not the charge is ended. If the charge is ended, the flow of FIG. 3 is ended, otherwise the processing is shifted to step 36.

The order of steps 31 to 34 and steps 35 to 38 may be reversed. The flow of FIG. 3 is implemented as a program of the ECU 14 of FIG. 1 or implemented as a program in a separately prepared controller.

The above flow is the case where the current command to the charger is not restricted, and the flow for actively controlling the current command will be described next. When the current command is narrowed, cross current is easily generated even with a small voltage difference, and switch control is also an important factor. The idea is to maximize the charging current as parallel as possible, and to make the capacitive battery current with a low current limit value the maximum charging current. This concept is described in FIG.

In FIG. 4, when the sum of the estimated current of the capacitive battery pack 22 and the estimated current of the power battery pack 21 exceeds the maximum current of the charger, the open circuit voltage of the capacitive battery pack 22 + the capacitive battery Current of pack 22 × DC resistance of capacitive battery pack 22 = open circuit voltage of power battery pack 21 + current of power battery pack 21 × DC resistance of power battery pack 21 and maximum current = current of power battery pack 21 It is taken as the intersection of the straight line used as the electric current of + capacity type battery pack 22.

In FIG. 4, the horizontal axis represents the current ic 41 of the capacitive battery pack 22, and the vertical axis represents the constraints ic ≦ Icmax 43 and ip ≦ Ipmax 44 with the current ip 42 of the power battery pack 21. Voltage condition Vc + rcic = Vp + in parallel It is a figure which becomes rpip45. 41 is a capacitive battery current axis (+ is the charge side), 42 is a power battery current axis (+ is the charge side), 43 is a maximum current of the

capacitive battery pack

22, 44 is a maximum current of the

power battery pack

21, 45 is a condition straight line where the voltage is equal, 46 is a current total straight line, and 47 is a maximum / crossflow restriction region.

Since the total current I is I = ic + ip 46, the intersection of the hatching rectangle 47 and the voltage condition of the constraint shown in FIG. 4 is the point at which I is maximized. That is, the charging current can be maximized by controlling the current command so as to maximize ic or ip. It may be determined based on the value of the intersection point 48 in FIG. 4 to switch which one is maximized. If the current I of the charger has an upper limit, the intersection of I = ic + ip and Vc + rcic = Vp + rpip is within the bounds of the rectangular maximum / crossflow constraint region 47 of the constraints, both The switch is turned on to charge the maximum current Imax of the charger. When the current is negative (discharge and cross flow), the switch on the current negative side may be disconnected. When the battery voltage is the maximum voltage Vmax, the maximum / crossflow restriction region 47 of the restriction condition rectangle of FIG. 4 may be adjusted to be Vc + rcic ≦ Vmax and Vp + rpip ≦ Vmax.

The above flow will be described with reference to FIG. First, in step 51 (DC resistance / open voltage measurement step), DC resistance and open voltage of each of the capacity type battery pack 22 and the power type battery pack 21 are measured. In this method, first, the voltage of each battery pack is measured, and then the switches of both batteries are turned on to determine the current of the charger from the current and voltage difference after setting the current to a minute value. Here, the DC resistance may use a value set in advance in a table.

Next, in step 52 (each battery pack estimated current calculation step), the estimated current is calculated. First, the charging current estimated values ip_cand and ic_cand calculated as Equation 2 and the charging current estimated values ip_cand2 and ic_cand2 calculated as Equation 3 are used. The value of Expression 2 is a candidate for an intersection of the condition line 45 where the voltage becomes equal to the maximum / crossflow restriction condition area 47 which is the restriction condition of FIG. 4. The value of Equation 3 is the point of intersection of the current total straight line 46 and the condition 45 where the voltage is equal.

ip_cand = (Vc-Vp) / rp + rc x min [Icmax, (Vmax-Vc) / rc] / rp
ic_cand = (Vp-Vc) / rc + rp × min (Ipmax, (Vmax-Vp) / rp) / rc (Equation 2)
Intersection points of Vc + rcic = Vp + rpip, Imax = ic + ip are ic_cand2, ip_cand2 (Equation 3)
If ip_cand + ic_cand max Imax at step 53 (charger maximum current determination), ic_cand> 0 at step 54 (capacitance battery pack 22 cross current determination), ip_cand at step 56 (power type battery pack 21 cross current determination) If> 0, both switches will be turned on with the current command value of the charger as ip_cand + ic_cand. In practice, since Imax is limited, the command in step 58 (charge command step for both batteries) is taken. Up to step 58, when the switch of the battery pack on the discharge side is turned off, the capacitive battery pack 22 and the power battery pack 21 are connected again in parallel again. When it is estimated that both the capacitive battery pack 22 and the power battery pack 21 are charged by the direct current resistance and the voltage 21, the capacitive battery pack 22 and the power battery pack 21 are again used as the capacitive battery pack switch 24 and the power battery It is connected in parallel via a pack switch 23.

In step 53, as the current estimated value when the capacitive battery pack 22 and the power battery pack 21 are connected in parallel, the voltage of the power battery pack 21 ≦ (upper limit of voltage of the complex storage system−open of the power battery pack 21 (Voltage) / restriction of direct current resistance of power type battery pack 21 and voltage of capacitive type battery pack 22 ≦ (upper limit voltage of complex system−open circuit voltage of capacitive type battery pack 22) / direct current resistance of capacitive type battery pack 22) and each Under limit of maximum current of the battery, open capacity of the battery pack 22 + current of the battery pack 22 × DC resistance of the battery pack 22 = open voltage of the battery pack 21 + powered battery pack A current of 21 × a direct current resistance of the power type battery pack 21 and a current of the capacity type battery pack 22 = a straight line which becomes an upper limit current of the capacity type battery pack 22 or a current of the power type battery pack 21 = an upper limit of the power type battery pack 21 Electricity It is an intersection of any of the straight lines that flow.

If ip_cand + ic_cand ≦ Imax in step 53 and if ic_cand ≦ 0 in step 54, the capacitive battery pack 22 in step 55 (the charging step of the power battery pack 21) is turned off, and the power battery pack 21 is On, set the current command of the charger to min (Ipmax, (Vmax-Vp) / rp). If it is determined in step 53 that ip_cand + ic_cand ≦ Imax, and if ic_cand> 0 in step 54 and ip_cand ≦ 0 in step 56, the power type battery pack 21 of step 57 (charging step of capacitive battery pack 22) is turned off. The capacitance type battery pack 22 is turned on, and the current command of the charger is set to min [Icmax, (Vmax-Vc) / rc].

If it is determined in step 53 that ip_cand + ic_cand> Imax, the charger is set with the maximum current Imax, but the cross current determination is necessary, and the cross current is further determined from the charging current candidate in Equation 3. This process corresponds to step 59 (judgement of cross flow of the capacitive battery pack 22), step 501.

If both ic_cand2 and ip_cand2 are within the constraint rectangle 47, turn on both battery packs and let the charger current command be Imax. That is, if Ic_cand2 ≦ 0 in step 58, the capacity type battery pack 22 in step 55 is turned off and the power type battery pack 21 is turned on, and the current command of the charger is min [Ipmax, (Vmax−Vp) / rp]. If ic_cand2> 0 in step 59 and ip_cand2 ≦ 0 in step 501, the power type battery pack 21 is turned off, the capacity type battery pack 22 is turned on, and the current command of the charger is min [Icmax, It is set as Vmax-Vc) / rc].

In steps 57, 58 and 55, in the combined storage system in which the capacitive battery pack 22 and the powered battery pack 21 are connected in parallel via the capacitive battery pack switch 24 and the powered battery pack switch 23, the combined storage system When charging a current command value to the charger when charging with the charger, the capacitive battery pack 22 and the power are determined by the open circuit voltage value and the DC resistance value of the capacitive battery pack 22 and the power battery pack 21. If it is estimated that the current value estimation of either of the capacitive battery pack 22 and the power battery pack 21 can be estimated to be a charge, then the capacitive battery pack switch 24 and the power battery are determined. With the pack switch 23 turned on, let the current command value be min (sum of estimated values of the capacity type battery pack 22 and the power type battery pack 21, the maximum charging current of the charger), If it is an estimated current value that causes discharge in either the capacitive battery pack 22 or the power battery pack 21, the switch on the battery pack side estimated to be discharged is turned off and the charge current command value is min (battery pack turned on The maximum current value on the side is set as (maximum voltage of the battery pack to be turned on-open voltage of the battery pack to be turned on) / battery pack direct current resistance to be turned on.

After completion of step 57, step 58 and step 55, it is determined in step 502 (judgement of charge end) whether or not the charge is ended. If the charging has not ended, the process returns to step 51. If the charging is ended, the flow of FIG. 5 is ended. When measuring DC resistance and open circuit voltage when returning to step 51, only the current voltage is measured without changing the state of the switch. If there is a change in the previous switch, DC resistance is calculated from the current and voltage difference. . Otherwise, the DC resistance is the previous estimated value or the value referred to in the table, and the open circuit voltage is taken as voltage-DC resistance × current.

A concrete method of constant value control in which the current of the power type battery is set to be min [Ipmax, (Vmax-Vp) / rp] in step 55 will be described. This control is to set the value min [Ipmax, (Vmax−Vp) / rp], but this is control to set it to Ipmax or the constant voltage Vmax. In the former case, there is no problem. In the latter case, if the charger does not have a constant voltage command command, feedback control is performed. Current command value = previous current command value + Gain × (Vmax-power type battery voltage). Gain uses a predetermined positive constant which does not become unstable.

Similarly, in step 57, the constant value control in which the current of the capacitive battery pack 22 is min [Icmax, (Vmax-Vc) / rc] is either Ipmax or control to be a constant voltage Vmax. In the former case, there is no problem, but in the latter case, if the charger does not have a constant voltage command command, feedback control is performed. Current command value = previous current command value + Gain × (Vmax-voltage of capacity type battery pack 22) . Gain uses a predetermined positive constant which does not become unstable.

In step 58, control is performed to set min (ip_cand + ic_cand, Imax) in the current command of the charger, but there is also a possibility that each battery current may exceed the maximum value. In this case, “current command value = current command value previous value + Gain 1 × (maximum current of power type battery pack 21−current measured value of power type battery pack 21) + Gain 2 × (−capacity of capacitive type battery pack 22) The feedback control is applied as the current measurement value of the battery pack 22. The values of Gain1 and Gain2 use predetermined positive constants which do not become unstable.

Finally, the definitions of the capacitive battery pack 22 and the power battery pack 21 in the present patent will be described. Here, the maximum current and the total capacity [kWh] are divided. The total battery pack capacity has a relationship of: Capacitive battery pack 22> power battery pack 21 capacity. As the maximum current, the maximum current of the total capacity battery pack 22> the maximum current of the total power battery pack 21. Here, "total" means that if the maximum current of one pack is 100A, it is converted to 200A if two parallel.

The battery in the battery unit 13 mounted in FIG. 1 may be an olivine iron lithium ion battery or a nickel-manganese-cobalt lithium ion mounted on an existing EV, or a separate semi-solid lithium ion A battery, a lead battery, or a nickel hydrogen battery may be used.

10 electric car, 11 motor generator, 12 inverter, 13 battery part
14 ECU, 15 communication lines, 16 quick chargers, 17 charging connectors, 18 power lines
21 power type battery pack, 22 capacity type battery pack
23 Power Battery Pack Switch, 24 Capacity Battery Pack Switch

Claims

In a complex storage system in which a capacitive battery pack and a power battery pack are connected in parallel via a capacitive battery pack switch and a power battery pack switch,
When charging the composite storage system, the capacitive battery pack switch and the power battery pack switch are turned on to start charging, and the current flowing to either the capacitive battery pack or the power battery pack is discharged. A combined storage system that turns off the switch of the battery pack that has become the discharge side when it becomes.
In the combined storage system of claim 1,
When the switch of the battery pack on the discharge side is turned off and the capacitive battery pack and the power battery pack are connected in parallel again, the direct current resistance of the capacitive battery pack and the power battery pack and When it is estimated that both the capacitive battery pack and the power battery pack are charged according to the voltage, the capacitive battery pack and the power battery pack are again used as the capacitive battery pack switch and the power battery pack switch. Complex power storage system connected in parallel through.
In a combined storage system in which a capacitive battery pack and a powered battery pack are connected in parallel via a capacitive battery pack switch and a powered battery pack switch,
When charging the composite storage system with a charger, when sending a current command value to the charger side, the capacity is determined according to the open circuit voltage value and DC resistance value of the capacity type battery pack and the power type battery pack. The current estimated value in the case of connecting the battery pack and the power pack in parallel is obtained, and if it is estimated that the current value estimation of either the capacity battery pack or the power pack is also charging, the capacity pack switch And turn on the power type battery pack switch, and let the current command value be min (sum of estimated current values of the capacity type battery pack and the power type battery pack, maximum charging current of the charger),
If it is an estimated current value to be discharged by either the capacitive battery pack or the power battery pack, the switch on the battery pack side presumed to be discharged is turned off and the charge current command value is min (battery pack turned on Composite power storage system that sets the maximum current value on the side, (maximum voltage of the battery pack to be turned on-open voltage of the battery pack to be turned on) / battery pack direct current resistance to be turned on.
In the combined storage system of claim 3,
As a current estimated value when the capacity type battery pack and the power type battery pack are connected in parallel,
Voltage of the power type battery pack ≦ (upper limit voltage of the complex storage system−open voltage of the power type battery pack) / constraint of direct current resistance of the power type battery pack and voltage ≦ (capacitance of the complex type battery pack) Based on the upper voltage limit of the system-open voltage of the capacitive battery pack / DC resistance of the capacitive battery pack) and the restriction of less than the maximum current of each battery, open voltage of the capacitive battery pack + the capacitive battery pack Current × DC capacity of the capacity type battery pack = open voltage of the power type battery pack + current of the power type battery pack × DC capacity of the power type battery pack and current of the capacity type battery pack = capacity type battery A composite storage in which a straight line which is the upper limit current of the pack, or a current of the power type battery pack = a straight line which is the upper limit current of the power type battery pack System.
In the combined storage system of claim 4,
When the sum of the estimated current of the capacitive battery pack and the estimated current of the power battery pack exceeds the maximum current of the charger, the open circuit voltage of the capacitive battery pack + the capacity of the capacitive battery pack Current x DC resistance of the capacitive battery pack = open voltage of the power battery pack + current of the power battery pack x DC resistance of the power battery pack and maximum current = current of the power battery pack + the capacity Combined storage system, which is the intersection of the straight lines that are the current of the battery pack.