JP6434245B2 - Charging rate estimation device and power supply system - Google Patents

Description

  The present invention relates to a charging rate estimation device that estimates a charging rate of a battery pack including a plurality of battery cells, and a power supply system including the same.

  In various vehicles such as an electric vehicle (EV) that runs using an electric motor and a hybrid vehicle (HEV) that runs using both an engine and an electric motor, a lithium ion battery or nickel is used as a power source for the electric motor. A battery module including an assembled battery having a plurality of battery cells (unit cells) made of a secondary battery such as a hydrogen rechargeable battery is mounted.

  In some battery cells of such a battery module, deterioration of some battery cells may proceed faster than other battery cells due to individual differences, ambient temperature deviations, and the like. And since the capacity | capacitance (current capacity | capacitance, electric power capacity | capacitance) which deteriorated battery cell will decrease, charge may expire before charge of the other battery cell which has not progressed. The other battery cells are completely discharged before they are fully discharged. And since a battery module is performed according to the deteriorated battery cell about the charge / discharge, the other battery cell which has not deteriorated cannot fully be used up, and the whole battery module is adjusted according to the deteriorated battery cell. Will substantially reduce the capacity.

  Therefore, a battery module including such a deteriorated battery cell can be used for the entire battery module when the charge of the deteriorated battery cell has expired (charging rate 100%) even if the charge of other battery cells has not expired. When it is assumed that charging has expired and the deteriorated battery cell has been completely discharged (charge rate 0%), it is assumed that the entire battery module has been completely discharged even if other battery cells have not been fully discharged. Could not be used enough. And in such a structure, the charging rate of the deteriorated battery cell was estimated as a charging rate of the whole battery module.

  Therefore, for example, in the technique described in Patent Document 1, an arbitrary battery cell among a plurality of battery cells is selectively connected to an inductor, energy of a battery cell having a high voltage is stored in the inductor, By transferring the stored energy to a battery cell having a low voltage, the voltage of each battery cell is made uniform efficiently. As a result, when the charging rate of the battery module varies, energy is transferred from a battery cell having a high voltage to a battery cell having a low voltage, thereby leveling (balancing) the charging rates of a plurality of battery cells. Can do.

JP2013-13292A

  However, by using the technique described in Patent Document 1, it is impossible to accurately estimate the charging rate of the entire battery module in a configuration in which the charging rates of a plurality of battery cells are leveled and uniform.

  The present invention aims to solve this problem. That is, the present invention provides a charging rate estimation device capable of more accurately estimating the charging rate of the entire assembled battery in a configuration for leveling the charging rates of a plurality of battery cells included in the assembled battery, and the charging rate estimation. It aims at providing the power supply system provided with the apparatus.

The invention described in claim 1 is a charge rate estimation device that estimates the charge rate of the entire assembled battery having a plurality of battery cells whose charge rate is leveled in order to achieve the above object,
The number of the plurality of battery cells is n, the current chargeable capacity of each of the plurality of battery cells is C1 to Cn, and the plurality of batteries corresponding to the product of the current chargeable capacity and the charge rate of each of the plurality of battery cells. and E1~En each remaining power amount of the cell, Ea an average value of each of the remaining power amount E1~En of the plurality of battery cells, the loss factor of the remaining power amount with the leveling of the charging rate L Then, the charging rate estimation device has charging rate estimation means for estimating the charging rate SOCall of the entire assembled battery using the following formula.
SOCall = [(E1 +... + En)
−L × (| E1−Ea | +... + | En−Ea |) / 2]
/(C1+...+Cn)

  According to a second aspect of the present invention, in the first aspect of the present invention, the charging rate estimation unit may determine a current chargeable capacity of each of the plurality of battery cells, and an initial value of each of the plurality of battery cells. The storage capacity and the degree of deterioration are calculated by multiplying each other, and the remaining power storage capacity of each of the plurality of battery cells is calculated by multiplying the current storage capacity and charge rate of each of the plurality of battery cells by each other. It is characterized by being.

  In order to achieve the above object, the invention described in claim 3 is a battery pack, a charge rate leveling device for leveling the charge rates of a plurality of battery cells included in the battery pack, and the entire battery pack. A power supply system comprising a charging rate estimation device for estimating a charging rate, wherein the charging rate estimation device comprises the charging rate estimation device according to claim 1 or 2. It is.

  According to the present invention, the charging rate of the entire assembled battery is estimated in consideration of the loss associated with the leveling of the charging rate in the remaining amount of charge (the amount of charge stored in the battery cell) of each of the plurality of battery cells. The charge rate of the entire assembled battery can be estimated with higher accuracy.

It is a figure which shows schematic structure of the power supply system of one Embodiment of this invention. It is a figure which shows typically an example of the relationship between the voltage between the both electrodes of the battery cell with which the assembled battery of the power supply system of FIG. 1 is equipped, and a charging rate. It is a flowchart which shows an example of the charge rate leveling process which the control part of the control apparatus of the power supply system of FIG. 1 performs. It is a figure which shows typically the transfer of the electric charge from the battery cell in the power supply system of FIG. 1 to an auxiliary battery. It is a figure which shows typically the transfer of the electric charge from the auxiliary | assistant battery to a battery cell in the power supply system of FIG. It is a flowchart which shows an example of the charging rate estimation process which the control part of the control apparatus of the power supply system of FIG. 1 performs. It is a figure which shows typically the state of the some battery cell which an assembled battery has. It is a figure which shows typically the other state of the some battery cell which an assembled battery has.

  Hereinafter, a charging rate estimation apparatus according to an embodiment of the present invention and a power supply system including the same will be described with reference to FIGS.

  FIG. 1 is a diagram showing a schematic configuration of a power supply system according to a first embodiment of the present invention. FIG. 2 is a diagram schematically illustrating an example of a relationship between a voltage between both electrodes of a battery cell included in the battery pack of the power supply system of FIG. 1 and a charging rate. FIG. 3 is a flowchart showing an example of the charge rate leveling process performed by the control unit of the charge rate leveling device of the power supply system of FIG. FIG. 4 is a diagram schematically showing charge transfer from the battery cell to the auxiliary battery in the power supply system of FIG. FIG. 5 is a diagram schematically showing charge transfer from the auxiliary battery to the battery cell in the power supply system of FIG. 1. FIG. 6 is a flowchart illustrating an example of a charging rate estimation process performed by the control unit of the control device of the power supply system of FIG. 7 and 8 are diagrams schematically showing a state of a plurality of battery cells included in the assembled battery.

  The power supply system of the present embodiment is mounted on a vehicle such as an electric vehicle, for example, and supplies power to high-voltage electrical components such as an electric motor of the vehicle and charges a plurality of battery cells included in an assembled battery of the power supply system. The rate is leveled (balanced) so that more power can be output. Moreover, the charging rate of the whole assembled battery is estimated. Of course, the present invention may be applied to devices and systems other than vehicles such as electric vehicles.

  The state of charge (SOC) of the battery cell includes a current storage current amount ratio (SOCi) to a chargeable current capacity, a current storage power ratio to a chargeable power capacity (SOCp), and the like. However, any charging rate may be used, and in this embodiment, the charging rate (SOC) is simply used. The same applies to the charging rate SOCall of the assembled battery. Moreover, the deterioration degree (SOH; State of Health) of a battery cell is the ratio of the current chargeable capacity to the initial chargeable capacity.

  As shown in FIG. 1, the power supply system of this embodiment (indicated by reference numeral 1 in the figure) includes a battery module 10, an auxiliary battery 17, a control device 20 as a charge rate leveling device and a charge rate estimating device, and It is equipped with.

  The battery module 10 includes an assembled battery 11 and a circuit breaker 15 connected in series between the assembled battery 11 and the high-voltage electrical component L1. The assembled battery 11 has a plurality of battery cells 12, and each of the plurality of battery cells 12 is connected in series. As the battery cell 12, for example, a secondary battery such as a lithium ion battery or a nickel metal hydride battery is used. The battery cell 12 may be a single cell, or may be a combination of a plurality of single cells connected in parallel or in series.

  Such a battery cell 12 has an electromotive force portion e that generates a voltage and an internal resistance r. The battery cell 12 generates a voltage v between both electrodes, and this voltage v is determined by a voltage ve generated by electromotive force by the electromotive force unit e and a voltage vr generated by current flowing through the internal resistance r (v = Ve + vr). In the battery cell 12, the internal resistance r changes according to the deterioration degree SOH, that is, the deterioration degree SOH of the battery cell 12 can be estimated by the internal resistance r.

  The auxiliary battery 17 is composed of a lead storage battery that supplies power to the low-voltage electrical component L2 of the vehicle. The auxiliary battery 17 also supplies power to the control device 20 described later. As the auxiliary battery 17, a secondary battery such as a lithium ion battery or a nickel metal hydride battery may be used in addition to the lead storage battery.

  The control device 20 includes a cell monitoring unit 21, a switch array 22, a bidirectional DC-DC converter 23, and a control unit 30.

  The cell monitoring unit 21 includes, for example, a plurality of analog switches and relay devices, and is provided so that each of the plurality of battery cells 12 included in the assembled battery 11 can be selectively connected to a control unit 30 described later. The cell monitoring unit 21 switches connection by a control signal from the control unit 30 and connects one battery cell 12 specified by the control signal among the plurality of battery cells 12 to the control unit 30. The control unit 30 detects a voltage between both electrodes of the connected battery cell 12.

  The switch array 22 includes, for example, a plurality of analog switches and relay devices, and is provided so that each of the plurality of battery cells 12 included in the assembled battery 11 can be selectively connected to a bidirectional DC-DC converter 23 described later. ing. The switch array 22 switches connection according to a control signal from the control unit 30 and connects one battery cell 12 designated by the control signal among the plurality of battery cells 12 to the bidirectional DC-DC converter 23. The switch array 22 can be energized in both directions between the battery cell 12 and the bidirectional DC-DC converter 23.

  The bidirectional DC-DC converter 23 converts a DC voltage input from one terminal and outputs it as a different DC voltage from the other terminal, and converts a DC voltage input from the other terminal to convert the DC voltage from one terminal. It is a voltage converter that outputs as a different DC voltage. In the bidirectional DC-DC converter 23, one terminal is selectively connected to the plurality of battery cells 12 included in the assembled battery 11 via the switch array 22, and the other terminal is connected to the auxiliary battery 17. The bidirectional DC-DC converter 23 charges the auxiliary battery 17 with electric power from the battery cell 12 and charges the battery cell 12 with electric power from the auxiliary battery 17. In the present embodiment, the auxiliary battery 17 is connected to the bidirectional DC-DC converter 23 and the low-voltage electrical component L2, but is not limited thereto. For example, the auxiliary battery 17 is connected only to the bidirectional DC-DC converter 23 and configured to charge and discharge with the battery cell 12 via the bidirectional DC-DC converter 23 and the switch array 22. It may be.

  The control unit 30 includes a microcomputer having a CPU, ROM, RAM, and the like, and controls the entire power supply system 1. The ROM stores in advance a control program for causing the CPU to function as various means such as a charging rate estimating means. The CPU functions as the various means by executing the control program. Further, the ROM includes various parameters (reference charge rate range, difference upper limit value, number n of the plurality of battery cells 12, each of the plurality of battery cells 12 used in the charge rate leveling process and the charge rate estimation process described later. An initial chargeable capacity Cp (common to all of the plurality of battery cells 12) is stored.

  The control unit 30 includes a plurality of output ports, and these output ports are connected to the cell monitoring unit 21, the switch array 22, and the bidirectional DC-DC converter 23. The control unit 30 outputs a control signal from the output port, switches the connection between the cell monitoring unit 21 and the switch array 22, and controls the operation of the bidirectional DC-DC converter 23. The output port of the control unit 30 is also connected to the circuit breaker 15 of the battery module 10 and outputs a control signal from the output port to control the operation of the circuit breaker 15.

  The control unit 30 includes an input port, and this input port is connected to the battery cell 12 via the cell monitoring unit 21. The control unit 30 performs analog-digital conversion on the voltage input to the input port, and acquires a value indicating the voltage between both electrodes of the battery cell 12.

  The control unit 30 includes another input port, and this input port is connected to a current detection circuit (not shown) that outputs a signal having a voltage corresponding to the current flowing through the assembled battery 11 (that is, the battery cell 12). Yes. The control unit 30 performs analog-digital conversion on the signal input to the other input port, and acquires a value indicating the current flowing through the battery cell 12.

  The control unit 30 acquires the voltage between both electrodes of the battery cell 12 and the current flowing at that time, and estimates the deterioration degree SOH of the battery cell 12 based on a plurality of combinations of these voltage and current. Specifically, in a system in which voltage and current are orthogonal to each other, two points with the combination of voltage and current as coordinates are plotted (the voltages differ in each combination), and the slope of the straight line connecting these two points Can be obtained as the internal resistance r. Then, an SOH conversion table corresponding to the internal resistance r is stored in the ROM in advance, and the SOH is estimated by applying the internal resistance r to the conversion table.

  The control unit 30 detects the charging rate SOCk (k = 1 to n) of the battery cell 12 based on the voltage between both electrodes of the battery cell 12. In the present embodiment, with respect to the voltage between both electrodes of the battery cell 12, the charge upper limit voltage Vth is 4.0 V and the discharge lower limit voltage Vtl is 3.0 V, and the voltage between the charge upper limit voltage Vth and the discharge lower limit voltage Vtl Changes with respect to the charging rate SOCk as shown in the graph of FIG. Charging rate relationship information indicating the relationship between the voltage between both electrodes of the battery cell 12 and the charging rate SOCk is acquired in advance by preliminary measurement, simulation, or the like and stored in the ROM in an information table format or the like. The charging rate SOCk is detected by applying a voltage to. Of course, this is merely an example. In addition to this, when the voltage of the battery cell 12 and the charging rate SOCk change linearly, the charging rate SOCk is set to be 4.0V when the voltage of the battery cell 12 is 4.0V. The charging rate SOCk may be 50% when the voltage is 3.5V, and the charging rate SOCk may be 0% when the voltage is 3.0V. By using the open-circuit voltage of the battery cell 12 (the voltage between the electrodes when the electrodes are open (or close to it)) as the voltage for detecting the charge rate SOCk, the charge rate SOCk can be obtained with high accuracy. Can be detected.

  The communication port of the control unit 30 is connected to an in-vehicle network (not shown) (for example, a controller area network (CAN)) and is connected to a display device such as a combination meter of the vehicle through the in-vehicle network. The CPU of the control unit 30 transmits the state and the like of the assembled battery 11 to the display device through the communication port and the in-vehicle network, and displays the state and the like of the assembled battery 11 on the display device based on the signal.

  The control unit 30 also detects the charging rate of the auxiliary battery 17. As an example, the control unit 30 detects the charging rate of the auxiliary battery 17 by receiving a signal indicating the charging rate of the auxiliary battery 17 from an electronic control device or the like that controls the auxiliary battery 17 through the in-vehicle network. .

  Next, an example of processing (charging rate leveling processing) executed by the control unit 30 of the control device 20 described above will be described with reference to the flowchart of FIG.

  In step S110, the battery cell 12 having the highest voltage between both electrodes among the plurality of battery cells 12 of the assembled battery 11 (hereinafter referred to as “highest voltage battery cell 12H”) and the battery cell having the lowest voltage between both electrodes. 12 (hereinafter referred to as “minimum voltage battery cell 12L”). Specifically, the control unit 30 outputs a control signal to the cell monitoring unit 21 to connect the plurality of battery cells 12 to the control unit 30 in order, and the voltage between both electrodes of the plurality of battery cells 12. Is detected. And after the control part 30 detects the voltage between the both electrodes of all the some battery cells 12, it detects the battery cell 12 with the said highest voltage as the highest voltage battery cell 12H, and the battery cell with the lowest said voltage 12 is detected as the lowest voltage battery cell 12L. Then, the process proceeds to step S120.

  In step S120, the charging rate SOCH of the highest voltage battery cell 12H and the charging rate SOCL of the lowest voltage battery cell 12L are detected. Specifically, the control unit 30 detects the charging rate SOCH based on the voltage between both electrodes of the highest voltage battery cell 12H, and similarly, the charging rate based on the voltage of the lowest voltage battery cell 12L. Detect SOCL. Then, the process proceeds to step S130.

  In step S130, control unit 30 determines whether or not at least one of charging rate SOCH of highest voltage battery cell 12H and charging rate SOCL of lowest voltage battery cell 12L is out of the reference charging rate range. In the present embodiment, as an example, the upper limit of the reference charge rate range is set to 90% and the lower limit is set to 10%. If at least one of the charging rate SOCH and the charging rate SOCL is out of the reference charging rate range, the process proceeds to step S140 (Y in S130), and both the charging rate SOCH and the charging rate SOCL are within the reference charging rate range. If there is, the process returns to step S110 (N in S130).

  In step S140, control unit 30 determines whether or not difference value ΔSOC between charging rate SOCH and charging rate SOCL exceeds a difference upper limit value. In the present embodiment, the upper limit difference is set to 2% as an example. If the difference value ΔSOC exceeds the difference upper limit value, the process proceeds to step S150 (Y in S140), and if the difference value ΔSOC is equal to or less than the difference upper limit value, the process returns to step S110 (N in S140).

  In step S150, the control unit 30 outputs a control signal to the switch array 22 to connect the highest voltage battery cell 12H to the bidirectional DC-DC converter 23. Then, the process proceeds to step S160.

  In step S160, the control unit 30 outputs a control signal to the bidirectional DC-DC converter 23 to operate the bidirectional DC-DC converter 23 so as to charge the auxiliary battery 17 with the power of the highest voltage battery cell 12H. . Then, the process proceeds to step S170.

  In step S170, it is determined whether or not the auxiliary battery 17 has been charged by a predetermined amount. Specifically, the control unit 30 outputs a control signal to the cell monitoring unit 21, connects the highest voltage battery cell 12H to the control unit 30, and detects the voltage between both electrodes of the highest voltage battery cell 12H. Based on this voltage, the charging rate SOCH of the highest voltage battery cell 12H is detected. Then, the control unit 30 determines whether or not the charging rate SOCH has decreased by a predetermined value (for example, 1%) from the start of charging. If the charging rate SOCH has not decreased by the predetermined value, the auxiliary battery 17 is charged by a predetermined amount. If it is determined that the auxiliary battery 17 has not been charged (N in S170) and has decreased by a predetermined value, it is determined that the auxiliary battery 17 has been charged by a predetermined amount, and the process proceeds to step S180. (Y in S170). In step S170, the control unit 30 also detects the charging rate of the auxiliary battery 17, and the charging of the auxiliary battery 17 should be stopped even when the charging rate of the auxiliary battery 17 increases and reaches 100%. The process proceeds to step S180.

  In step S180, the control unit 30 outputs a control signal to the bidirectional DC-DC converter 23 to stop the bidirectional DC-DC converter 23. Then, the process proceeds to step S190.

  In step S <b> 190, the control unit 30 outputs a control signal to the switch array 22 to connect the lowest voltage battery cell 12 </ b> L to the bidirectional DC-DC converter 23. Then, the process proceeds to step S200.

  In step S200, the control unit 30 outputs a control signal to the bidirectional DC-DC converter 23, and operates the bidirectional DC-DC converter 23 so as to charge the lowest voltage battery cell 12L with the power of the auxiliary battery 17. . Then, the process proceeds to step S210.

  In step S210, it is determined whether or not the minimum voltage battery cell 12L has been charged by a predetermined amount. Specifically, the control unit 30 outputs a control signal to the cell monitoring unit 21, connects the lowest voltage battery cell 12L to the control unit 30, and detects the voltage between both electrodes of the lowest voltage battery cell 12L. Based on this voltage, the charging rate SOCL of the lowest voltage battery cell 12L is detected. Then, the control unit 30 determines that the charging rate SOCL is a predetermined value from the start of charging (for a charging rate corresponding to the same capacity as the capacity (charge) transferred from the highest voltage battery cell 12H to the auxiliary battery 17 in S160 to S180). It is determined whether or not it has increased, and if it has not increased by a predetermined value, the determination is repeated assuming that the minimum voltage battery cell 12L is not charged by a predetermined amount (N in S210), and if it has increased by a predetermined value, It is determined that the minimum voltage battery cell 12L has been charged by a predetermined amount, and the process proceeds to step S220 (Y in S210). In other words, in step S210, the charging operation is continued until the same capacity as that charged from the highest voltage battery cell 12H to the auxiliary battery 17 is charged from the auxiliary battery 17 to the lowest voltage battery cell 12L. In step S210, the control unit 30 also detects the charging rate of the auxiliary battery 17, and even when the charging rate of the auxiliary battery 17 decreases and reaches a predetermined lower limit (for example, 90%), the minimum voltage Proceed to step S220 to stop charging the battery cell 12L.

  In step S220, the control unit 30 outputs a control signal to the bidirectional DC-DC converter 23 to stop the bidirectional DC-DC converter 23. And in order to perform a charging rate leveling process again, it returns to step S110.

  The control unit 30 functions as a battery cell detection unit by executing step S110 described above, functions as a charge rate detection unit by executing step S120 described above, and executes steps S150 and S190 described above. It functions as connection switching control means.

  Next, an example of the operation for leveling the charging rate of the plurality of battery cells 12 of the power supply system 1 (control device 20) described above will be described.

  The control device 20 detects the voltage between the electrodes of each of the plurality of battery cells 12 included in the assembled battery 11 of the battery module 10, and the charging rate SOCH of the highest voltage battery cell 12H having the highest voltage and the highest voltage of this voltage. The charge rate SOCL of the low minimum voltage battery cell 12L is detected (S110, S120).

  For example, when the charging rate SOCH is 91% and the charging rate SOCL is 87%, the charging rate SOCH is out of the reference charging rate range (Y in S130), and the difference between the charging rate SOCH and the charging rate SOCL Since the value exceeds the difference upper limit value (Y in S140), the auxiliary battery 17 is charged with the power of the highest voltage battery cell 12H to decrease the charging rate SOCH (91% → 90%) (S150 to S180, FIG. 4) After that, the lowest voltage battery cell 12L is charged by the power of the auxiliary battery 17 to increase the charging rate SOCL (S190 to S220, FIG. 5). At this time, the charging rate SOCL of the lowest voltage battery cell 12L increases by the charging rate corresponding to the same capacity as the capacity (charge) transferred from the highest voltage battery cell 12H to the auxiliary battery 17.

  Or, for example, when the charging rate SOCH is 13% and the charging rate SOCL is 9%, the charging rate SOCL is out of the reference charging rate range (Y in S130), and the difference between the charging rate SOCH and the charging rate SOCL Since the value exceeds the difference upper limit value (Y in S140), the auxiliary battery 17 is charged with the power of the highest voltage battery cell 12H to decrease the charging rate SOCH (13% → 12%) (S150 to S180, FIG. 4) After that, the lowest voltage battery cell 12L is charged by the power of the auxiliary battery 17 to increase the charging rate SOCL (S190 to S220, FIG. 5). At this time, the charging rate SOCL of the lowest voltage battery cell 12L increases by the charging rate corresponding to the same capacity as the capacity (charge) transferred from the highest voltage battery cell 12H to the auxiliary battery 17.

  By doing in this way, the charging rate of the some battery cell 12 which the assembled battery 11 has can be equalized.

  Next, an example of processing (charge rate estimation processing) executed by the control unit 30 of the control device 20 described above will be described with reference to the flowchart of FIG. This charging rate estimation process is executed independently of the above-described charging rate leveling process.

  In step T110, the charging rate SOCk (k = 1 to n; n is the number of battery cells 12) of each of the plurality of battery cells 12 is detected. Specifically, the control unit 30 outputs a control signal to the cell monitoring unit 21 to connect the plurality of battery cells 12 to the control unit 30 in order, and the voltage between both electrodes of the plurality of battery cells 12. Is detected. And control part 30 detects those charge rates SOCk based on the voltage between both electrodes, after detecting the voltage between both electrodes of all the plurality of battery cells 12. FIG. Then, the process proceeds to Step T120.

  In step T120, the deterioration degree SOHk (k = 1 to n; n is the number of battery cells 12) of each of the plurality of battery cells 12 is detected. Specifically, the control unit 30 outputs a control signal to the cell monitoring unit 21 to sequentially connect each battery cell 12 to the control unit 30, and to detect the voltage between both electrodes of each battery cell 12 and the voltage detection. Current is detected twice in a short time during which the charging rate SOC does not change (however, the voltage is different in each detection), and the internal resistance r of each battery cell 12 is obtained from these voltages and currents. The degree of degradation SOHk is detected based on the resistance r. Since the deterioration degree SOH of the battery cell 12 does not change abruptly, for example, the deterioration degree SOHk of each of the plurality of battery cells 12 is detected at the timing when the ignition of the vehicle is turned on. The deterioration degree SOH stored in the RAM may be used while the ignition is ON. Then, the process proceeds to Step T130.

In step T130, the charging rate SOCall of the entire assembled battery 11 is estimated. Specifically, the control unit 30 estimates the charging rate SOCall of the entire assembled battery 11 using the following equation. In the following formula, L is a loss coefficient of the remaining amount Ek of electricity storage accompanying leveling of the charge rate SOCk, that is, a coefficient representing the degree of loss of electric charge transferred along with leveling, for example, L is 0 .1 indicates that 10% of the total charge transferred with leveling is lost.
Current storage capacity Ck of battery cell (k = 1 to n)
= Initial chargeable capacity Cp x Degradation degree SOHk
Remaining power Ek of battery cell (k = 1 to n)
= Current chargeable capacity Ck × Charge rate SOCk
Average value Ea = (E1 +... + En) / n of the remaining power levels E1 to En of the battery cells
Charging rate of the entire assembled battery SOCall = [(E1 +... + En)
−L × (| E1−Ea | +... + | En−Ea |) / 2]
/(C1+...+Cn)

  And after estimating charge rate SOCall, it returns to step T110 and performs charge rate estimation processing again.

  The control unit 30 functions as a charging rate estimation unit by executing the above-described steps T110 to T130.

  Next, an example of the operation of estimating the charging rate of the assembled battery 11 of the power supply system 1 (control device 20) described above will be described. Here, a description will be given assuming that the assembled battery 11 has five battery cells 12 (n = 5) and the loss coefficient L is 0.1.

  The control device 20 detects the voltage between the electrodes of each of the plurality of battery cells 12 included in the assembled battery 11 of the battery module 10, and detects the charge rate SOCk of each of the plurality of battery cells 12 based on this voltage. (T110). And control device 20 detects each voltage and current of a plurality of battery cells 12, and detects each degree of degradation SOHk of a plurality of battery cells 12 based on this voltage and current (T120).

For example, as shown in FIG. 7, it is assumed that the current chargeable capacity Ck, the deterioration degree SOHk, the charge rate SOCk, and the remaining charge Ek of each battery cell have the values shown below.
C1 = 100 Ah, SOH1 = 100%, SOC1 = 30%, E1 = 30 Ah
C2 = 100 Ah, SOH2 = 100%, SOC2 = 30%, E2 = 30 Ah
C3 = 100 Ah, SOH3 = 100%, SOC3 = 30%, E3 = 30 Ah
C4 = 100 Ah, SOH4 = 100%, SOC4 = 30%, E4 = 30 Ah
C5 = 40Ah, SOH5 = 40%, SOC5 = 0%, E5 = 0Ah

These values are applied to the above formula.
Ea = (30 + 30 + 30 + 30 + 0) / 5 = 24
SOCall = [(30 + 30 + 30 + 30 + 0)
−0.1 × (| 30-24 | + | 30-24 | + | 30-24 |
+ | 30-24 | + | 0-24 |) / 2]
/(100+100+100+100+40)=26.7%

  Therefore, 26.7% is obtained as the charging rate SOCall of the assembled battery 11 as a whole.

Alternatively, for example, as shown in FIG. 8, it is assumed that the current chargeable capacity Ck, the deterioration degree SOHk, the charge rate SOCk, and the remaining charge Ek of each battery cell have the following values.
C1 = 100 Ah, SOH1 = 100%, SOC1 = 70%, E1 = 70 Ah
C2 = 100 Ah, SOH2 = 100%, SOC2 = 70%, E2 = 70 Ah
C3 = 100 Ah, SOH3 = 100%, SOC3 = 70%, E3 = 70 Ah
C4 = 100 Ah, SOH4 = 100%, SOC4 = 70%, E4 = 70 Ah
C5 = 40Ah, SOH5 = 40%, SOC5 = 100%, E5 = 40Ah

These values are applied to the above formula.
Ea = (70 + 70 + 70 + 70 + 40) / 5 = 64
SOCall = [(70 + 70 + 70 + 70 + 40)
−0.1 × (| 70−64 | + | 70−64 | + | 70−64 |
+ | 70-64 | + | 40-64 |) / 2]
/(100+100+100+100+40)=72.2%

  Therefore, 72.2% is obtained as the charging rate SOCall of the assembled battery 11 as a whole.

  As described above, according to the present embodiment, the charging rate SOCall of the entire assembled battery 11 is estimated in consideration of the loss associated with the leveling of the charging rate SOCk in each of the remaining power levels Ek of the plurality of battery cells 12. The charging rate SOCall of the entire assembled battery 11 can be estimated with higher accuracy.

  Although the present invention has been described with reference to the preferred embodiments, the charging rate estimation device and the power supply system of the present invention are not limited to the configurations of these embodiments. The above-described embodiments are merely representative examples of the present invention, and those skilled in the art can implement various modifications in accordance with conventionally known knowledge without departing from the scope of the present invention. Of course, such modifications are also included in the scope of the present invention as long as the configuration of the charging rate estimation device and the power supply system of the present invention are provided.

DESCRIPTION OF SYMBOLS 1, 2 Power supply system 10 Battery module 11 Battery assembly 12 Battery cell 12H Maximum voltage battery cell 12L Minimum voltage battery cell 15 Circuit breaker 17 Auxiliary battery 18 Alternator 20, 20A Control device (charge rate leveling device, charge rate estimation device)
21 Cell monitoring unit 22 Switch array 23 Bidirectional DC-DC converter 30, 30A Control unit (charging rate estimation means)
L1 High-voltage electrical component L2 Low-voltage electrical component Ck Initial chargeable capacity of battery cell Ek Battery charge remaining amount Ea Average value of charge remaining of each of a plurality of battery cells SOHk Battery cell deterioration degree SOCk Battery cell charge Rate SOCall The total battery charge rate L Loss factor

Claims (3)

A charging rate estimation device for estimating a charging rate of an entire assembled battery having a plurality of battery cells whose charging rate is leveled,
The number of the plurality of battery cells is n, the current chargeable capacity of each of the plurality of battery cells is C1 to Cn, and the plurality of batteries corresponding to the product of the current chargeable capacity and the charge rate of each of the plurality of battery cells. and E1~En each remaining power amount of the cell, Ea an average value of each of the remaining power amount E1~En of the plurality of battery cells, the loss factor of the remaining power amount with the leveling of the charging rate L Then, the charging rate estimation device has charging rate estimation means for estimating the charging rate SOCall of the entire assembled battery using the following formula.
SOCall = [(E1 +... + En)
−L × (| E1−Ea | +... + | En−Ea |) / 2]
/(C1+...+Cn) The charging rate estimation means is
Calculate the current chargeable capacity of each of the plurality of battery cells by multiplying the initial chargeable capacity and the degree of deterioration of each of the plurality of battery cells,
The power storage remaining amount of each of the plurality of battery cells is calculated by multiplying the current chargeable capacity and charge rate of each of the plurality of battery cells by each other. Charging rate estimation device. A power supply system comprising: an assembled battery; a charging rate leveling device for leveling a charging rate of a plurality of battery cells included in the assembled battery; and a charging rate estimation device for estimating a charging rate of the entire assembled battery. ,
The power supply system, wherein the charging rate estimation device is configured by the charging rate estimation device according to claim 1.

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