WO2013047400A1

WO2013047400A1 - Battery system, state-of-charge estimation device, electric vehicle, mobile body, power storage device, and power supply device

Info

Publication number: WO2013047400A1
Application number: PCT/JP2012/074324
Authority: WO
Inventors: 智哉寺内; 晶彦山田
Original assignee: 三洋電機株式会社
Priority date: 2011-09-27
Filing date: 2012-09-24
Publication date: 2013-04-04
Also published as: JP2014231988A

Abstract

A battery system (500) comprises battery cells (10) and a state-of-charge estimation device (200). A processing unit of the state-of-charge estimation device (200) calculates the states of charge of the battery cells (10) during charging and discharging periods on the basis of the terminal voltages of the battery cells (10) during non-charging and non-discharging periods before and after the charging and discharging periods, calculates the internal impedances of the battery cells (10) during the charging and discharging periods on the basis of the current flowing through the battery cells (10) during the charging and discharging periods, the terminal voltages of the battery cells (10) during the charging and discharging periods, and the calculated state of charge during the charging and discharging periods, and updates internal impedance information to be stored in a storage unit on the basis of the temperatures of the battery cells (10) during the charging and discharging periods and the calculated internal impedances.

Description

BATTERY SYSTEM, CHARGE STATE ESTIMATION DEVICE, ELECTRIC VEHICLE, MOBILE BODY, POWER STORAGE DEVICE, AND POWER SUPPLY DEVICE

The present invention relates to a battery system, a charging state estimation device, an electric vehicle, a moving body, a power storage device, and a power supply device.

A battery system including a chargeable / dischargeable battery cell is used for a moving body driven by electric power such as an electric automobile and a power supply device for storing and supplying electric power. In order to appropriately control charging / discharging of the battery cell, it is required to accurately acquire the charging state of the battery cell.

In the battery state-of-charge estimation device described in Patent Document 1, an actual measurement is performed using a map (hereinafter referred to as an internal resistance map) including information on the correlation between the battery temperature stored in advance and the internal resistance of the battery. The battery internal resistance is estimated from the battery temperature. An estimated charge / discharge current is obtained from the estimated battery internal resistance, the actually measured battery voltage, and the open circuit voltage of the battery based on the previously estimated SOC (charge / discharge state). The SOC is estimated by integrating the obtained estimated charge / discharge current.

When the SOC estimation operation reaches a predetermined number of times, the battery internal resistance is calculated from the measured charge / discharge current and the measured battery voltage, and the internal resistance map is calculated based on the calculated battery internal resistance and the measured battery temperature. It is corrected.

JP 2004-93551 A

In the above battery charge state estimation device, in order to calculate the battery internal resistance used for correcting the internal resistance map, the open circuit voltage of the battery is required. On the other hand, the open circuit voltage of the battery is obtained from the SOC estimated as described above. When estimating the SOC, the battery internal resistance estimated with reference to the internal resistance map is used.

Therefore, if the internal resistance map before correction is not accurate, the battery internal resistance calculated for correction is not accurate. As a result, the internal resistance map cannot be accurately corrected. Further, by repeatedly performing such correction, an error is cumulatively superimposed on the internal resistance map. As a result, the SOC cannot be estimated with high accuracy.

An object of the present invention is to provide a battery system, a charging state estimation device, an electric vehicle, a moving body, a power storage device, and a power supply device that can accurately estimate the charging state of a battery cell.

A battery system according to the present invention includes a battery cell, a voltage detection unit that detects a terminal voltage of the battery cell, a temperature detection unit that detects a temperature of the battery cell, and a charging state estimation device that estimates a charging state of the battery cell. The charging state estimation device includes a storage unit that stores internal impedance information representing a relationship between the internal impedance and temperature of the battery cell, and estimates a charging state of the battery cell based on the internal impedance information stored in the storage unit And a processing unit that updates the internal impedance information. The processing unit is a first non-charge / discharge in which the battery cell is not charged and discharged before the charge / discharge period in which the battery cell is charged or discharged. After the first terminal voltage of the battery cell detected by the voltage detector in the period and the charge / discharge period Calculating the state of charge of the battery cell during the charge / discharge period based on the second terminal voltage of the battery cell detected by the voltage detection unit during the second non-charge period when the battery cell is not being charged or discharged. The internal impedance of the battery cell during the charge / discharge period is calculated based on the current flowing through the battery cell during the discharge period, the terminal voltage of the battery cell detected by the voltage detection unit during the charge / discharge period, and the calculated charge state during the charge / discharge period. The internal impedance information stored in the storage unit is updated based on the temperature detected by the temperature detection unit and the calculated internal impedance during the charge / discharge period.

According to the present invention, the state of charge of the battery cell can be accurately estimated.

It is a block diagram which shows the structure of the battery system which concerns on embodiment. It is a block diagram for demonstrating the detail of a charge condition estimation apparatus. It is a figure which shows an example of an internal resistance table. It is a figure which shows an example of an SOC table. It is a figure which shows the change of the battery current at the time of charge of a battery cell, a battery voltage, and battery temperature. It is a figure which shows the change of the electric current integration value at the time of charge of a battery cell, and the change of SOC. It is a figure for demonstrating the update of an internal resistance table. It is an example of temperature change coefficient information and SOC change coefficient information. It is a flowchart of a SOC estimation process. It is a flowchart of a SOC estimation process. It is a flowchart which shows the other example of a SOC estimation process. It is a flowchart which shows the other example of a SOC estimation process. It is a figure which shows the other example of a change of the battery current in the charging / discharging period, battery voltage, and battery temperature. It is a figure which shows the example of the internal resistance table for charge, and the internal resistance table for discharge. It is a block diagram which shows the structure of the electric vehicle concerning embodiment. It is a block diagram which shows the structure of the power supply device which concerns on embodiment.

Hereinafter, a battery system, a charging state estimation device, an electric vehicle, a moving body, a power storage device, and a power supply device according to embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the internal resistance of the battery cell is used as the internal impedance of the battery cell.

(1) Battery System (1-1) Configuration FIG. 1 is a block diagram showing the configuration of the battery system according to the first embodiment of the present invention. As shown in FIG. 1, the battery system 500 includes a battery cell group 100, a charge state estimation device 200, a current detection unit 201, a voltage detection unit 202, a temperature detection unit 203, and an output unit 205. The battery cell group 100 includes a plurality of battery cells 10. In this example, the plurality of battery cells 10 of the battery cell group 100 are connected in series. As each battery cell 10, secondary batteries, such as a lithium ion battery, are used, for example. Note that some or all of the plurality of battery cells 10 may be connected in parallel. For example, a plurality of battery cell groups 100 (battery cell group 100 in FIG. 1) including a plurality of directly connected battery cells 10 may be provided, and the plurality of battery cell groups 100 may be connected in parallel to each other. . Alternatively, a plurality of battery cell groups 100 ′ including a plurality of battery cells 10 connected in parallel may be provided, and the plurality of battery cell groups 100 ′ may be connected in series with each other. Or such battery cell group 100 and battery cell group 100 'may coexist. Further, the battery cell group 100 may have only one battery cell 10. As the value of the internal impedance of the battery cell 10, the value of the internal resistance of the battery cell 10 can be used without considering the value of the internal reactance of the battery cell 10.

The current detection unit 201 includes, for example, a shunt resistor, a differential amplifier, and an A / D (analog / digital) converter. A current sensor may be used as the current detection unit 201. The current detection unit 201 is connected to the battery cell group 100 in series. The current detection unit 201 detects a current flowing through the plurality of battery cells 10 (hereinafter referred to as a battery current), and supplies the detected current value to the charge state estimation device 200 as current information.

The voltage detection unit 202 is connected to the positive terminal and the negative terminal of each battery cell 10. The voltage detection unit 202 detects a terminal voltage of each battery cell 10 (hereinafter referred to as a battery voltage), and supplies the detected terminal voltage value to the charge state estimation device 200 as voltage information.

The temperature detection unit 203 detects the temperature of each battery cell 10 (hereinafter referred to as the battery temperature), and gives the detected temperature value to the charge state estimation device 200 as temperature information. As the temperature detection unit 203, for example, a plurality of thermistors are used, and as the temperature of the battery cell 10, for example, the surface temperature of the battery cell 10 is detected. In this case, the thermistor may be attached to each battery cell 10, or the thermistor may be attached only to some of the plurality of battery cells 10. When the thermistors are attached only to some of the battery cells 10, for example, the temperatures of the other battery cells 10 are estimated based on the temperatures of the some battery cells 10. The temperature detected by the thermistor is used as the temperature of some battery cells 10, and the estimated temperature is used as the temperature of other battery cells 10.

The charging state estimation device 200 estimates the charging state of each battery cell 10 based on the current information from the current detection unit 201, the voltage information from the voltage detection unit 202, and the temperature information from the temperature detection unit 203. The state of charge refers to information related to the amount of charge of the battery cell 10 such as current, amount of electricity stored, or electric capacity. For example, SOC (charge rate), remaining capacity, depth of discharge (DOD), integrated current value or difference in amount of electricity stored including. In the present embodiment, SOC is used as the state of charge. The SOC means the ratio of the remaining capacity to the full charge capacity of each battery cell 10. The depth of discharge means the ratio of the chargeable capacity (capacity obtained by subtracting the remaining capacity from the full charge capacity of the battery cell 10) to the full charge capacity of the battery cell 10, and is represented by (100−SOC)%. . The difference in the charged amount means a difference between the SOC of the battery cell 10 and a predetermined reference value. The charging state estimation device 200 outputs the estimated charging state (SOC in this example) to the output unit 205 or an external control device. For example, a main control unit 608 (FIG. 15) described later or a controller 712 (FIG. 16) described later corresponds to an external control device.

The output unit 205 includes, for example, a liquid crystal display panel, a plasma display panel, an organic EL (electroluminescence) panel, or a speaker. The output unit 205 includes, for example, at least one of a battery voltage, a battery current, a battery temperature, an internal resistance, an open circuit voltage (OCV), an SOC, an internal resistance table TA (FIG. 3) and an SOC table TB described later, and the like. Display one. Further, the output unit 205 may present an alarm or work instruction to the user or service person when an abnormality occurs in the battery system 500, for example. The abnormality of the battery system 500 includes, for example, overcharge and overdischarge of the battery cell group 100, malfunction and failure of the charge state estimation device 200, and the like.

(1-2) Charging State Estimation Device FIG. 2 is a block diagram for explaining details of the charging state estimation device 200. As shown in FIG. 2, the charging state estimation device 200 includes an internal resistance acquisition unit 211, an SOC acquisition unit 212, a data array storage unit 213, a table update unit 214, and a storage unit 215. The internal resistance acquisition unit 211, the SOC acquisition unit 212, the data array storage unit 213, and the table update unit 214 are examples of processing units.

The internal resistance acquisition unit 211 uses a later-described internal resistance table TA stored in the storage unit 215 to acquire temperature information from the temperature detection unit 203 and an internal resistance corresponding to the SOC acquired by the SOC acquisition unit 212. (FIG. 3 described later). The SOC acquisition unit 212 calculates the open voltage of the battery cell 10 based on the current information from the current detection unit 201, the voltage information from the voltage detection unit 202, and the internal resistance acquired by the internal resistance acquisition unit 211, and a storage unit An SOC corresponding to the calculated open-circuit voltage is acquired using an SOC table TB described later stored in 215 (FIG. 4 described later). The SOC acquisition unit 212 outputs the acquired SOC to the output unit 205 (FIG. 1) or an external control device. Moreover, the SOC acquisition unit 212 calculates a current integrated value that is an integrated value of the current flowing through the battery cell 10 based on the current information from the current detection unit 201.

The data array storage unit 213 associates the current information from the current detection unit 201, the voltage information from the voltage detection unit 202, the temperature information from the temperature detection unit 203, and the current integrated value calculated by the SOC acquisition unit 212 with each other. Save as a data array. The table update unit 214 updates the internal resistance table stored in the storage unit 215 based on the data array stored by the data array storage unit 213. The storage unit 215 stores a control program and various information such as an internal resistance table TA, an SOC table TB, and an integrated current value calculated by the SOC acquisition unit 212.

The function of the charging state estimation device 200 is realized by hardware such as a CPU (Central Processing Unit) and a memory, a computer program (the above control program), and the like. For example, the internal resistance acquisition unit 211, the SOC acquisition unit 212, the data array storage unit 213, and the table update unit 214 correspond to a module (for example, a function) of a computer program. In this case, the functions of the internal resistance acquisition unit 211, the SOC acquisition unit 212, the data array storage unit 213, and the table update unit 214 are realized by the CPU executing the computer program stored in the memory. Note that some or all of the internal resistance acquisition unit 211, the SOC acquisition unit 212, the data array storage unit 213, and the table update unit 214 may be realized by hardware.

In battery system 500 according to the present embodiment, the first terminal voltage of battery cell 10 in the first non-charge / discharge period before the charge / discharge period and the battery cell in the second non-charge / discharge period after the charge / discharge period. The SOC that is the state of charge of the battery cell 10 during the charge / discharge period is calculated based on the 10 second terminal voltage. An internal resistance is calculated as the internal impedance of the battery cell during the charge / discharge period based on the calculated SOC and the battery current and battery voltage during the charge / discharge period. In this case, for example, as described later, the SOC in the charge / discharge period can be calculated based on the integrated current value or the elapsed time. Moreover, an open circuit voltage can be acquired from the calculated SOC, and an internal resistance can be calculated based on the acquired open circuit voltage, battery current, and battery voltage.

The internal resistance table TA, which is internal impedance information stored in the storage unit 215, is updated based on the calculated internal resistance and the temperature of the battery cell 10 during the charge / discharge period. As a result, the SOC of the battery cell 10 can be accurately estimated without being affected by individual differences and deterioration of the battery cell 10.

(1-3) Internal Resistance Table and SOC Table The internal resistance of the battery cell 10 depends on the temperature and SOC of the battery cell 10. In the present embodiment, an internal resistance table TA indicating the relationship between the temperature, SOC, and internal resistance of battery cell 10 is stored in storage unit 215 of charge state estimation device 200. The internal resistance table TA is an example of internal impedance information representing the relationship between the internal resistance of the battery cell and the temperature. Instead of the internal resistance table TA, a function representing the relationship between the temperature of the battery cell and the internal resistance may be used.

FIG. 3 is a diagram showing an example of the internal resistance table TA. In FIG. 3, X11, X12,..., X1m, X21, X22,..., X2m, ..., Xn1, Xn2, ..., Xnm are values of the internal resistance of the battery cell 10. In the example of FIG. 3, the value of the internal resistance is shown every time the battery temperature differs by 5 ° C. and every time the SOC changes by 10%. The internal resistance acquisition unit 211 acquires the internal resistance corresponding to the temperature information from the temperature detection unit 203 and the SOC acquired by the SOC acquisition unit 212 from the internal resistance table TA.

Also, the SOC of the battery cell 10 depends on the open voltage of the battery cell 10. In the present embodiment, SOC table TB indicating the relationship between the open circuit voltage of battery cell 10 and the SOC is stored in storage unit 215 of charge state estimation device 200. The SOC table TB is an example of charge state information representing the relationship between the charge state of the battery cell 10 and the open circuit voltage. Instead of the SOC table TB, a function representing the relationship between the open voltage of the battery cell and the state of charge may be used.

FIG. 4 is a diagram showing an example of the SOC table TB. In FIG. 4, the horizontal axis indicates the SOC, and the vertical axis indicates the open circuit voltage. The SOC acquisition unit 212 calculates the open circuit voltage of the battery cell 10 based on the current information from the current detection unit 201, the voltage information from the voltage detection unit 202, and the internal resistance acquired by the internal resistance acquisition unit 211, and is calculated. The SOC corresponding to the open circuit voltage is obtained from the SOC table TB. Note that the relationship between the SOC of the battery cell 10 and the open circuit voltage does not depend on the temperature and deterioration of the battery cell 10.

(1-4) Estimation of SOC The estimation of the SOC by the state-of-charge estimation device 200 will be described by taking the battery cell 10 as an example. FIG. 5 is a diagram illustrating changes in battery current, battery voltage, and battery temperature when the battery cell 10 is charged. 5A to 5C, the vertical axis indicates the battery current I, the battery voltage V, and the battery temperature T, respectively, and the horizontal axis indicates time. In FIG. 5A, the battery current at the time of charging is represented by a positive value, and the battery current at the time of discharging is represented by a negative value. In this example, as shown in FIG. 5A, the battery cell 10 is charged with a constant current.

The battery voltage (terminal voltage of the battery cell 10) is equal to the open voltage of the battery cell 10 at a time before the time t1 when the charging of the battery cell 10 is started. Therefore, the SOC acquisition unit 212 acquires the battery voltage Va detected by the voltage detection unit 202 at this time as voltage information, and acquires the SOC corresponding to the acquired battery voltage Va from the SOC table TB of FIG.

When charging of the battery cell 10 is started at time t1, the battery voltage rises by the voltage drop due to the internal resistance from the open voltage of the battery cell 10, as shown in FIG. In this case, the internal resistance acquisition unit 211 acquires the internal resistance corresponding to the battery temperature given as temperature information and the SOC acquired by the SOC acquisition unit 212 from the internal resistance table TA. In this case, the SOC acquired by the SOC acquisition unit 212 is the SOC acquired at the time point one cycle before, as will be described later. The internal resistance table TA is the internal resistance table TA updated when the previous charging or discharging is stopped. In this example, as shown in FIG. 5C, when the battery cell 10 is charged, the battery temperature increases from Ta to Tb.

The SOC acquisition unit 212 uses the following equation (1) to provide the internal resistance acquired by the internal resistance acquisition unit 211, the battery current I given as current information (detected by the current detection unit 201), and the voltage information. An open circuit voltage E of the battery cell 10 is calculated from a given battery voltage V (detected by the voltage detection unit 202), and an SOC corresponding to the calculated open circuit voltage E is obtained from the SOC table TB. In the following formula (1), R is an internal resistance of the battery cell 10. In equation (1), the battery current during charging is represented by a positive value, and the battery current during discharging is represented by a negative value.

E = V + IR (1)
After the charging of the battery cell 10 is stopped at the time t2, when a certain time (hereinafter referred to as a transient time) TP elapses, the battery voltage is released from the battery cell 10 as before the charging of the battery cell 10 is started. Equal to the voltage. Here, the open circuit voltage of the battery cell 10 is equal to the terminal voltage of the battery cell 10 when the battery cell 10 is not charged or discharged and is in a steady state. That is, the transient time TP is a time from when charging / discharging of the battery cell 10 is stopped until the terminal voltage of the battery cell 10 is stabilized (becomes a steady state). Therefore, after time t3 when the transition time TP has elapsed from time t2, the SOC acquisition unit 212 acquires the battery voltage Vb detected by the voltage detection unit 202 at that time as voltage information, and obtains the acquired battery voltage Vb. The corresponding SOC is acquired from the SOC table TB.

Thus, the SOC of the battery cell 10 is estimated in the charge / discharge period in which the battery cell 10 is charged or discharged and in the non-charge / discharge period in which the battery cell 10 is not charged or discharged.

(1-5) Update of Internal Resistance Table As described above, in order to estimate the SOC of the battery cell 10, the value of the internal resistance of the battery cell 10 is required. In this case, it is desirable to use the latest internal resistance value.

During the charge / discharge period of the battery cell 10, the data array storage unit 213 stores the battery current, the battery voltage, the battery temperature, and the current integrated value as a data array each time a predetermined storage condition SR is satisfied. The storage condition SR is, for example, that the amount of change in battery temperature since the previous storage of the data array is equal to or greater than a predetermined threshold, or the amount of change in SOC since the previous storage of the data array is It is at least one of exceeding a predetermined threshold value. Note that the battery current, the battery voltage, the battery temperature, and the current integrated value immediately before the charging / discharging of the battery cell 10 is started may be stored as a data array. The threshold value for the change amount of the battery temperature is, for example, 5 ° C., and the threshold value for the change amount of the SOC is, for example, 10%. Hereinafter, a time point when the data array is stored in the data array storage unit 213 (a time point when the storage condition SR is satisfied) is referred to as a storage time point. In the internal resistance table TA, the storage capacity does not become too large and the internal resistance can be accurately estimated. For example, as shown in FIG. The value of the internal resistance is shown for every% difference. The threshold value of the change amount of the battery temperature and the change amount of the SOC in the storage condition SR are preferably equal to or less than the battery temperature interval and the SOC interval in the internal resistance table TA.

When charging / discharging of the battery cell 10 is stopped, the table update unit 214 updates the internal resistance table TA based on the data array stored by the data array storage unit 213. In this example, after the update of the internal resistance table TA is completed, the data array storage unit 213 stores the SOC and the current integrated value when the charging / discharging of the battery cell 10 is stopped in order to suppress an increase in storage capacity. And erase the other data array. As shown below, the SOC and current integrated value at the time of charge / discharge stop stored in the data array storage unit 213 are used as the SOC and current integrated value at the start of the next charge / discharge.

Hereinafter, the update of the internal resistance table TA will be described by taking as an example a case where the charging of the battery cell 10 is stopped. FIG. 6 shows a change in the integrated current value and a change in the SOC when the battery cell 10 is charged. In FIG. 6A and FIG. 6B, the vertical axis indicates the current integrated value S_I and the SOC, respectively, and the horizontal axis indicates time. Also, the period from time t0 to time t1 is the previous non-charge / discharge period, the period from time t1 to time t2 is the charge / discharge period, and the period after time t2 is the current non-charge / discharge period. The previous and current non-charging / discharging periods are examples of first and second non-charging / discharging periods before and after the charging / discharging period. The example of FIG. 6 corresponds to the example of FIG. 5 described above, and is an example in which the battery cell 10 is charged with a constant current. In this case, the current integrated value S_I increases linearly. Further, since the SOC increases or decreases according to the current integrated value S_I, in this case, it increases linearly.

At the end time t2 of the charge / discharge period, the data array storage unit 213 uses the SOC and current integrated value at the time t0 of the previous non-charge / discharge period as well as each storage time in the charge / discharge period (time t1 to t2) as the data array. The battery current, battery voltage, battery temperature, and current integrated value of P1, P2,..., Pi,. Here, Pi represents an arbitrary storage time, and Pn represents the last storage time in the charge / discharge period.

First, the table update unit 214 acquires the SOC at the time t0 of the previous non-charge / discharge period from the data array storage unit 213 as the SOCpre at the start time t1 of the charge / discharge period. In addition, the table updating unit 214, after the transition time TP has elapsed from the end time t2 of the charge / discharge period, the SOC corresponding to the battery voltage Vb (FIG. 5B) at that time (for example, the time t3 in FIG. 5). Is obtained as SOCpost from the SOC table TB. The battery voltage Va in FIG. 5B is an example of the first terminal voltage in the first non-charging period, and the battery voltage Vb in FIG. 5B is the second terminal in the second non-charging period. It is an example of a voltage. 6B is an example of the first charge state in the first non-charge / discharge period, and SOCpost in FIG. 6B is the second charge state in the second non-charge / discharge period. It is an example.

The time point t1 is an example of the time point in the first non-charge / discharge period in which charging or discharging is not performed, and the time points t2 and t3 are the time points in the second non-charging / discharging period in which charging or discharging is not performed. It is an example. As the first terminal voltage and the first charging state in the first non-charging / discharging period, it is preferable to use the terminal voltage and the charging state immediately before the start of charging / discharging, and the second terminal in the second non-charging / discharging period. As the voltage and the second state of charge, it is preferable to use the terminal voltage and the state of charge immediately after the transition time TP has elapsed since charging / discharging was stopped. That is, the time point t1 is an example of a suitable time point in the first non-charge / discharge period, and the time point t3 is an example of a suitable time point in the second non-charge / discharge period.

Subsequently, the table updating unit 214 uses the following equation (2) to calculate the storage time point P1 from the current integrated values (FIG. 6A) of the storage time points P1 to Pn stored as the data array in the data array storage unit 213. The SOC of .about.Pn is estimated (FIG. 6 (b)). In the following formula (2), SOC [i] and S_I [i] are the SOC and current integrated value of the battery cell 10 at an arbitrary storage time point Pi in the charge / discharge period. S_Ipre is an integrated current value at time t0 of the previous non-charge / discharge period stored in the data array storage unit 213. S_Ipost is an integrated current value at the end time t2 of the charge / discharge period.

The amount of change in the current integrated value from the start time t1 of the charge / discharge period to the arbitrary storage time Pi (S_I [i] −S_Ipre) and the current integrated value from the arbitrary storage time Pi to the end time t2 of the charge / discharge period The ratio with the change amount (S_Ipost−S_I [i]) is calculated from the change amount of SOC (SOC [i] −SOCpre) from the start time t1 of the charge / discharge period to the arbitrary storage time point Pi and the arbitrary storage time point Pi. It is equal to the ratio with the amount of change in SOC (SOCpost-SOC [i]) until the end time t2 of the charge / discharge period. Therefore, the SOC [i] at an arbitrary storage time Pi is obtained by the above equation (2). Hereinafter, the SOC at each storage point Pi calculated by the table updating unit 214 in this way is referred to as an estimated SOC. The estimated SOC is an example of the state of charge during the charge / discharge period.

Subsequently, the table updating unit 214 stores the storage time points P1 to Pn based on the calculated estimated SOCs of the storage time points P1 to Pn and the battery currents and battery voltages of the storage time points P1 to Pn stored in the data array storage unit 213. Estimate the internal resistance. Specifically, the table update unit 214 acquires, from the SOC table TB, the open circuit voltage corresponding to the estimated SOC at the storage time points P1 to Pn as the open circuit voltage at the storage time points P1 to Pn. Further, the table update unit 214 uses the above equation (1) to obtain the obtained release voltage at the storage time points P1 to Pn and the battery currents and battery voltages at the storage time points P1 to Pn stored in the data array storage unit 213. Based on the above, the internal resistance at the storage time points P1 to Pn is calculated. Hereinafter, the internal resistance estimated from the estimated SOC by the table updating unit 214 in this way is referred to as an estimated internal resistance Rt. The estimated internal resistance Rt is an example of the internal resistance during the charge / discharge period.

FIG. 7 is a diagram for explaining the update of the internal resistance table TA. In FIG. 7, the horizontal axis indicates the SOC, and the vertical axis indicates the battery temperature T. As described above, internal resistance corresponding to all battery temperatures and all SOCs is not included in the internal resistance table TA. For example, each time the battery temperature differs by a certain value and every time the SOC differs by a certain value The resistance is included in the internal resistance table TA. In FIG. 7, the relationship between the battery temperature and the SOC corresponding to the internal resistance included in the internal resistance table TA is indicated by a plurality of “□”. Hereinafter, the battery temperature and the SOC corresponding to the internal resistance included in the internal resistance table TA are referred to as a table corresponding temperature and a table corresponding SOC, respectively.

In FIG. 7, the relationship between the battery temperature and the estimated SOC at each storage time Pi is represented by “x”. In this example, the relationship between the battery temperature and the estimated SOC at the storage time points P1 to P6 is shown. At storage time points P1 to P6, the battery temperature changes from Ta to Tb, and the SOC changes from SOCpre to SOCpost.

First, the table update unit 214 calculates a reference internal resistance Rs at each storage point Pi based on the internal resistance table TA before update. Specifically, when the battery temperature and the estimated SOC at any one of the storage times match the table corresponding temperature and the table corresponding SOC (storage time points P1, P4, P6 in the example of FIG. 7), the table update unit 214 acquires the internal resistance corresponding to the battery temperature and the estimated SOC at the time of storage as the reference internal resistance Rs from the internal resistance table TA before update. On the other hand, when the battery temperature and the estimated SOC at any one of the storage times do not match the table-corresponding temperature and the table-corresponding SOC (storage points P2, P3, P5 in the example of FIG. 7), the table updating unit 214 A plurality of table-corresponding temperatures and a plurality of internal resistances corresponding to the plurality of table-corresponding SOCs close to the estimated battery temperature and the estimated SOC that do not match “□” are acquired from the internal resistance table TA before update. The table updating unit 214 calculates an internal resistance corresponding to the battery temperature and the estimated SOC at the time of storage as a reference internal resistance Rs by interpolation calculation from the plurality of acquired internal resistances.

Subsequently, the table updating unit 214 calculates the internal resistance change coefficient Kr at each storage time point P1 to P6 using the following equation (3). In the following equation (3), Kr [i], Rs [i], and Rt [i] are an internal resistance change coefficient, a reference internal resistance, and an estimated internal resistance at an arbitrary storage point Pi in the charge / discharge period.

Kr [i] = Rs [i] ÷ Rt [i] (3)
Subsequently, based on the calculated internal resistance change coefficient Kr, the table updating unit 214 represents temperature change coefficient information indicating the relationship between the battery temperature and the internal resistance change coefficient, and the relationship between the SOC and the internal resistance change coefficient. Obtain SOC change coefficient information.

FIG. 8 (a) is an example of temperature change coefficient information, and FIG. 8 (b) is an example of SOC change coefficient information. In FIG. 8A, the horizontal axis indicates the battery temperature T, and the vertical axis indicates the internal resistance change coefficient Kr. In FIG. 8B, the horizontal axis indicates the SOC, and the vertical axis indicates the internal resistance change coefficient Kr.

As shown in FIG. 8A, based on the relationship between the battery temperature and the internal resistance change coefficient Kr at a plurality of storage time points P1 to P6, interpolation is performed between “X” corresponding to each storage time point P1 to P6. By the calculation, as shown by the solid line L1, the relationship between the battery temperature and the internal resistance change coefficient Kr in a certain temperature range is obtained. Here, the certain temperature range is equal to the temperature range included in the internal resistance table TA. In the example of FIG. 8A, in the temperature range lower than the battery temperature T at the storage time point P1, the internal resistance change coefficient Kr is set to be equal to the internal resistance change coefficient Kr at the storage time point P1. Further, in the temperature range higher than the battery temperature T at the storage time point P6, the internal resistance change coefficient Kr is set to be equal to the internal resistance change coefficient Kr at the storage time point P6.

Similarly, as shown in FIG. 8B, based on the relationship between the SOC and the internal resistance change coefficient Kr at each storage time point P1 to P6, interpolation between “X” corresponding to each storage time point P1 to P6 is performed. Thus, as shown by the solid line L2, the change in the internal resistance change coefficient Kr within a certain SOC range is obtained. Here, the constant SOC range is equal to the SOC range included in the internal resistance table TA. In the example of FIG. 8B, in the SOC range lower than the estimated SOC at the storage time point P1, the internal resistance change coefficient Kr is set to be constant and equal to the internal resistance change coefficient Kr at the storage time point P1. In the SOC range higher than the estimated SOC at the time point P6, the internal resistance change coefficient Kr is set to be constant and equal to the internal resistance change coefficient Kr at the storage time point P6.

The table updating unit 214 calculates the internal resistance change coefficient Kt corresponding to each combination of the table corresponding temperature and the table corresponding SOC based on the temperature change coefficient information and the SOC change coefficient information. Specifically, the table updating unit 214 acquires the internal resistance change coefficient Kr corresponding to one table-corresponding temperature from the temperature change coefficient information, and also changes the internal resistance corresponding to one table-corresponding SOC from the SOC change coefficient information. The coefficient Kr is acquired. The table updating unit 214 acquires the acquired internal resistance change coefficient Kr corresponding to the acquired one table corresponding temperature as the internal resistance change coefficient Ks corresponding to the combination of the one table corresponding temperature and the one table corresponding SOC. The square root of the product with the internal resistance change coefficient Kr corresponding to the table corresponding SOC is calculated.

For example, in the temperature change coefficient information of FIG. 8A, the internal resistance change coefficient when the table corresponding temperature is T11 is Kr11. In the SOC change coefficient information of FIG. 8B, the table corresponding SOC is SOC11. In some cases, the internal resistance change coefficient is Kr21. In this case, in FIG. 7, the internal resistance change coefficient Ks corresponding to the combination C11 of the table corresponding temperature T11 and the table corresponding SOC SOC11 is
Ks = √ (Kr11 × Kr21)
It becomes. In this way, the internal resistance change coefficient Kt corresponding to each combination of the table corresponding temperature and the table corresponding SOC is calculated.

Subsequently, the table updating unit 214 acquires the internal resistance corresponding to each combination of the table corresponding temperature and the table corresponding SOC as the internal resistance Rtable from the internal resistance table TA before the update. Further, as shown in the following formula (4), the table update unit 214 multiplies the acquired internal resistance Rtable by the internal resistance change coefficient Ks for each combination of the table corresponding temperature and the table corresponding SOC, thereby updating the table update value. Rnew is calculated.

Rnew = Ks × Rtable (4)
Subsequently, the table updating unit 214 updates the internal resistance (□ in FIG. 7) corresponding to each combination of the table corresponding temperature and the table corresponding SOC of the internal resistance table TA to the table update value Rnew. In this way, the update of the internal resistance table TA is completed.

(1-5) SOC Estimation Processing The charge state estimation device 200 performs SOC estimation processing based on the control program stored in the storage unit 215. 9 and 10 are flowcharts of the SOC estimation process. The charging state estimation device 200 repeatedly performs the SOC estimation processing of FIGS. 9 and 10 at a constant cycle (for example, a cycle of 250 ms).

As shown in FIG. 9, first, as described with reference to FIG. 2, the SOC acquisition unit 212 performs battery current and battery voltage based on the current information from the current detection unit 201 and the voltage information from the voltage detection unit 202. To get. Further, the internal resistance acquisition unit 211 acquires the battery temperature based on the temperature information from the temperature detection unit 203. Further, the data array storage unit 213 acquires the battery current, the battery voltage, and the battery temperature based on the current information from the current detection unit 201, the voltage information from the voltage detection unit 202, and the temperature information from the temperature detection unit 203 ( Step S1).

Next, the SOC acquisition unit 212 updates the current integrated value stored in the storage unit 215 to a value obtained by adding the battery current acquired in step S1 of the current SOC estimation process (step S2). Note that the initial value of the current integrated value stored in the storage unit 215 is zero. Next, the internal resistance acquisition unit 211 acquires the internal resistance corresponding to the battery temperature and the SOC estimated by the SOC acquisition unit 212 during the previous SOC estimation process from the internal resistance table TA stored in the storage unit 215 (Step S1). S3).

Next, the SOC acquisition unit 212 calculates the open circuit voltage of the battery cell 10 from the internal resistance, battery current, and battery voltage acquired by the internal resistance acquisition unit 211 using the above equation (1), and the acquired open circuit The SOC corresponding to the voltage is acquired from the SOC table TB stored in the storage unit 215. Further, the SOC acquisition unit 212 outputs the acquired SOC (step S4).

Next, the data array storage unit 213 determines whether or not the storage condition SR is satisfied based on the battery temperature and the SOC acquired by the SOC acquisition unit 212 (step S5). If the storage condition SR is not satisfied, the data array storage unit 213 performs a process of step S7 described later.

When the storage condition SR is satisfied, the data array storage unit 213 stores the battery current, battery voltage and battery temperature acquired in step S1, and the current integrated value calculated in step S2 as a data array (step S6). ). Next, the data array storage unit 213 determines whether or not a predetermined update condition is satisfied based on the battery current and the battery voltage (step S7).

The update condition is, for example, that a predetermined time has elapsed since the absolute value of the acquired battery current has become equal to or less than a predetermined threshold value. The predetermined threshold is determined according to the accuracy of the current detection unit 201 and is, for example, 500 mA. The predetermined time is determined according to the length of the transition time TP, and is, for example, several minutes. For example, 60 minutes is required to make the battery voltage more stable. The update condition may be immediately before the next charge / discharge of the battery cell 10 is started.

If the update condition is not satisfied, the charging state estimation device 200 ends the SOC estimation process. When the update condition is satisfied, the charging state estimation device 200 performs an internal resistance table update process (step S8), and ends the SOC estimation process.

As shown in FIG. 10, in the internal resistance table update process in step S8, first, as described above, the table update unit 214 calculates the estimated SOC of each storage time point Pi by interpolation calculation using the above equation (2). Calculate (step S11). Next, the table update unit 214 acquires the open circuit voltage corresponding to the estimated SOC at each storage time Pi from the SOC table TB stored in the storage unit 215, and uses the above equation (1) to acquire each acquired storage The estimated internal resistance at each storage time Pi is calculated from the open circuit voltage at the time Pi and the battery current and battery voltage at each storage time Pi stored in the data array storage unit 213 (step S12).

Next, the table updating unit 214 calculates the table update value Rnew corresponding to each combination of the table corresponding temperature and the table corresponding SOC as described above based on the estimated SOC, the estimated internal resistance, and the internal resistance table TA ( Step S13). Next, the table update unit 214 updates the internal resistance table TA stored in the storage unit 215 using the calculated table update value Rnew (step S14). Next, the data array storage unit 213 stores the SOC (SOCpost in FIG. 6B) and the current integrated value (S_Ipost in FIG. 6A) at the time of charge / discharge stop (step S15), and the data array Initialization is performed (step S16). Here, initialization of the data array means erasing the data array that has not been saved in step S15. Thereby, the charging state estimation apparatus 200 complete | finishes an internal resistance table update process.

(1-6) Effect In the present embodiment, the SOC is calculated as the state of charge of the battery cell 10 during the charge / discharge period based on the battery voltage during the non-charge / discharge period when the battery cell 10 is not charged or discharged. Based on the battery current and battery voltage during the charge / discharge period and the calculated SOC, the internal resistance of the battery cell 10 is calculated. The internal resistance table TA, which is internal impedance information stored in the storage unit 215, is updated based on the battery temperature and the calculated internal resistance during the charge / discharge period.

In this case, the internal resistance for updating the internal resistance table TA is calculated from the battery voltage in the non-charge / discharge periods before and after the charge / discharge period without using the internal resistance table TA. Thereby, even when the internal resistance table TA is not accurate, the internal resistance can be accurately estimated. Therefore, the internal resistance table TA can be updated accurately. As a result, the SOC of the battery cell 10 can be accurately estimated without being affected by individual differences and deterioration of the battery cell 10.

Further, in the present embodiment, an open circuit voltage corresponding to the SOC in the charge / discharge period is acquired based on the SOC table TB that is the charge state information stored in the storage unit 215. The internal resistance of the battery cell 10 is calculated based on the acquired open circuit voltage and the battery current and battery voltage during the charge / discharge period. Thereby, the internal resistance of the battery cell 10 in the charge / discharge period can be calculated with high accuracy.

In the present embodiment, the SOC of the battery cell 10 in the non-charge / discharge period is acquired based on the battery voltage in the non-charge / discharge period before and after the charge / discharge period. Based on the obtained SOC in the non-charge / discharge period and the integrated current value in the charge / discharge period, the SOC of the battery cell 10 in the charge / discharge period is calculated. Thereby, the SOC of the battery cell 10 during the charge / discharge period can be calculated with high accuracy.

(1-7) First Modification (1-7-1) Calculation of SOC Based on Elapsed Time In the above example, the table updating unit 214 calculates the current integrated value stored in the data array storage unit 213 and the upper The SOC at each storage point Pi in the charging period is calculated by interpolation calculation using Expression (2), but is not limited thereto. As in the above example, when the battery current is constant during the charge / discharge period, the amount of change in SOC per unit time is constant. Therefore, the table updating unit 214 performs each storage time point of the charging / discharging period by proportional distribution based on the elapsed time from the start time of the charging / discharging period without performing the interpolation calculation using the current integrated value and the above equation (2). The SOC at Pi may be calculated.

11 and 12 are flowcharts showing another example of the SOC estimation process. The example of FIGS. 11 and 12 will be described while referring to differences from the examples of FIGS. 9 and 10. In the SOC estimation process of FIG. 11, the process of step S2 (calculation of the current integrated value) is not performed. Further, instead of step S6, in step S6a, the data array storage unit 213 displays the battery current, battery voltage, battery temperature, and elapsed time or time information from the start of the charge / discharge period acquired in step S1. Save as a data array and do not save the integrated current value.

In the internal resistance table update process of step S8a, as shown in FIG. 12, unlike the example of FIG. 10, first, the table update unit 214 performs charge / discharge based on the battery current stored in the data array storage unit 213. It is determined whether or not the battery current during the period is constant (step S21). When the battery current in the charging / discharging period is constant, the table updating unit 214 does not perform the interpolation calculation using the current integrated value and the above equation (2) as described above, from the start time of the charging / discharging period. The estimated SOC at each storage time Pi is calculated by proportional distribution based on the elapsed time (step S11a). Thereafter, the table update unit 214 performs the processes of steps S12a to S14a. The processing in steps S12a to S14a in FIG. 12 is the same as the processing in steps S12 to S14 in FIG. Subsequently, the data array storage unit 213 stores only the SOC when charging / discharging is stopped (step S15a), and the data array storage unit 213 initializes the data array (step S16a).

On the other hand, if the battery current during the charging / discharging period is not constant in step S21, the table updating unit 214 does not perform the processes of steps S11a to S14a. In step S15a, the data array storage unit 213 stores only the SOC when charging / discharging is stopped, and in step S16a, the data array storage unit 213 initializes the data array.

(1-7-2) Effect In this example, when the battery current in the charge / discharge period is constant, based on the SOC in the non-charge period before and after the charge / discharge period and the elapsed time from the start time of the charge / discharge period, The state of charge of the battery cell 10 during the charge / discharge period is calculated. In this case, the amount of calculation is reduced as compared with the case where the interpolation calculation using the current integrated value and the above equation (2) is performed, so that the processing load on the table updating unit 214 is reduced. In addition, since it is not necessary to store the integrated current value, the storage capacity of the data array storage unit 213 can be reduced.

Further, in this example, the internal resistance table TA is updated when the battery current during the charge / discharge period is constant, and the internal resistance table TA is not updated when the battery current during the charge / discharge period is not constant. In this case, since the internal resistance table TA is selectively updated only when the battery current in the charge / discharge period is constant, the processing load on the charge state estimation device 200 is reduced, and the battery current in the charge / discharge period is reduced. The battery system 500 can be used even when it is not constant.

(1-8) Second Modification As described above, when the battery current during the charge / discharge period is constant, each storage is performed without performing the interpolation calculation using the current integrated value and the above equation (2). The SOC of the time point Pi can be obtained. On the other hand, when the battery current during the charge / discharge period is not constant, the SOC at each storage time Pi can be obtained by performing interpolation calculation using the current integrated value and the above equation (2).

FIG. 13 shows another example of changes in battery current, battery voltage, and battery temperature during the charge / discharge period. 13A to 13C, the vertical axis represents the battery current I, the battery voltage V, and the battery temperature T, respectively, and the horizontal axis represents time.

In the example of FIG. 13, the battery cell 10 is charged at the time points t1 to t11 and the time points t12 to t2 of the charge / discharge period, and the battery cell 10 is discharged at the time points t11 to t12. Further, the battery current is not constant when the battery cell 10 is charged and discharged.

Even when the battery current during the charge / discharge period is not constant as in this example, or when charging and discharging are performed alternately, as described with reference to FIGS. 5 and 6, the current integrated value and the above equation (2 ) Can be used to obtain the SOC at each storage point Pi. Examples of battery current fluctuations include, for example, sinusoidal, sawtooth, or random fluctuations. In either case, the SOC at each storage point Pi can be obtained in the same manner.

Thus, by performing the interpolation calculation using the current integrated value and the above equation (2), the SOC at each storage point Pi in the charge / discharge period is calculated regardless of the variation form of the battery current in the charge / discharge period. Can do. Thereby, the battery system 500 can be used in any situation.

Note that the processing in steps S11 to S14 in FIG. 10 and the processing in steps S11a to S16a in FIG. 12 may be selectively performed depending on whether or not the battery current in the charge / discharge period is constant. In this case, steps S2 and S6 in FIG. 9 are performed. For example, if the battery current during the charge / discharge period is constant in step S21 of FIG. 12, the table update unit 214 performs the processes of steps S11a to S16a of FIG. On the other hand, if the battery current during the charging / discharging period is not constant, the table updating unit 214 performs the processes of steps S11 to S16 in FIG.

Thus, when charging or discharging is performed at a constant current, the internal resistance table TA can be easily updated without performing an interpolation calculation using the current integrated value and the above equation (2). On the other hand, when charging or discharging is performed at a current other than a constant current, the internal resistance table TA can be accurately updated by performing an interpolation calculation using the current integrated value and the above equation (2).

(1-9) Third Modification In the case where charging / discharging of the battery cell 10 is performed at a constant current as in the second modification, a predetermined constant value is used in any charge / discharge period. When charging / discharging is performed only with the battery current, the data array storage unit 213 does not have to store the current and integrated current value during the charging / discharging period. In this case, as described above, the table updating unit 214 can calculate the SOC at each storage time Pi based on the elapsed time from the start time of the charge / discharge period. In addition, the battery current in the charge / discharge period is stored in advance in the storage unit 215, for example, so that the table update unit 214 acquires the open circuit voltage corresponding to the calculated SOC from the SOC table TB, and the acquired open circuit voltage Based on the battery voltage stored in the data array storage unit 213 and the battery current stored in the storage unit 215, the open circuit voltage at each storage time Pi can be calculated. Therefore, the internal resistance at each storage time Pi can be calculated without using the data array storage unit 213, the current during the charge / discharge period, and the current integrated value. Thereby, the processing load on the table updating unit 214 can be reduced, and the storage capacity of the data array storage unit 213 can be reduced.

(1-10) Fourth Modification As described above, when the SOC at each storage point Pi in the charge / discharge period is calculated using the integrated current value and the above equation (2), if one charge / discharge period becomes longer In this period, detection errors by the current detection unit 201 are accumulated, and the integration error of the current integration value increases. Thereby, there is a possibility that the SOC cannot be calculated accurately.

Therefore, when one charging / discharging period becomes longer than a predetermined period, the table updating unit 214 does not update the internal resistance table TA, and the data array storage unit 213 performs the SOC and current when charging / discharging is stopped. Only the storage of the integrated value (step S15 in FIG. 10) and the initialization of the data array (step S16 in FIG. 10) may be performed. In this case, the internal resistance table TA is prevented from being updated to an incorrect value.

(1-11) Fifth Modification Relationship between the temperature, SOC and internal resistance of the battery cell 10 during charging of the battery cell 10 and the relationship between the temperature, SOC and internal resistance of the battery cell 10 during discharging of the battery cell 10 May be different. In that case, different internal resistance tables TA may be used when the battery cell 10 is charged and discharged.

FIG. 14 (a) is an example of an internal resistance table for charging, and FIG. 14 (b) is an example of an internal resistance table for discharging. 14A, Y11, Y12,..., Y1m, Y21, Y22,..., Y2m,..., Yn1, Yn2, ..., Ynm are values of the internal resistance when the battery cell 10 is charged. It is. In the internal resistance table TA2 of FIG. 14B, Z11, Z12,..., Z1m, Z21, Z22,..., Z2m, ..., Zn1, Zn2, ..., Znm are values of the internal resistance when the battery cell 10 is discharged. It is.

The internal resistance acquisition unit 211 acquires the internal resistance from the internal resistance table TA1 when the battery cell 10 is charged, and the internal resistance from the internal resistance table TA2 when the battery cell 10 is discharged. Get resistance. Thereby, depending on whether the battery cell 10 is charged or discharged, the internal resistance can be obtained with high accuracy. The table updating unit 214 updates the internal resistance table TA1 after charging the battery cell 10, and updates the internal resistance table TA2 after discharging the battery cell 10. As a result, the internal resistance tables TA1 and TB1 can be accurately updated. As a result, the SOC of the battery cell 10 can be accurately estimated.

(1-12) Sixth Modification In the above embodiment, the internal resistance table TA shows the relationship between the temperature, SOC, and internal resistance of the battery cell 10, but the present invention is not limited to this, and the internal resistance table TA Only the relationship between the temperature of the cell 10 and the internal resistance may be shown. In this case, the internal resistance acquisition unit 211 acquires the internal resistance corresponding to the battery temperature given as temperature information from the internal resistance table TA. The table update unit 214 also updates the internal resistance table TA based on the calculated temperature change coefficient information. This makes it possible to reduce the processing load and the storage capacity.

(1-13) Other Modifications In the above example, the SOC is estimated for each battery cell 10 by the charging state estimation device 200. However, the present invention is not limited to this, and for example, the SOC of the entire battery cell group 100 is estimated. Also good.

In the above example, the SOC estimation process is performed at a constant cycle. However, the present invention is not limited to this, and for example, the SOC may be acquired at an arbitrary timing set in advance.

In the above example, the data array storage unit 213 stores the data array every time a predetermined storage condition SR is satisfied. However, the present invention is not limited to this, and for example, the data array storage unit 213 every time a certain time elapses. May store the data array.

(2) Electric vehicle and moving body An electric vehicle and a moving body according to the second embodiment of the present invention will be described. The electric vehicle and the moving body according to the present embodiment include battery system 500 according to the first embodiment. In the following, an electric vehicle will be described as an example of an electric vehicle.

(2-1) Configuration and Operation FIG. 15 is a block diagram showing the configuration of the electric vehicle. As shown in FIG. 15, electric vehicle 600 according to the present embodiment includes a vehicle body 610. The vehicle body 610 is provided with the battery system 500, the power conversion unit 601, the motor 602, the drive wheel 603, the accelerator device 604, the brake device 605, the rotation speed sensor 606, and the main control unit 608. When motor 602 is an alternating current (AC) motor, power conversion unit 601 includes an inverter circuit.

The battery system 500 is connected to the motor 602 via the power conversion unit 601 and to the main control unit 608. The main control unit 608 is given the state of charge (for example, SOC) of the battery cell group 100 from the state of charge estimation device 200. Further, an accelerator device 604, a brake device 605, and a rotation speed sensor 606 are connected to the main control unit 608. The main control unit 608 includes, for example, a CPU and a memory, or a microcomputer. Note that the charging state estimation device 200 may have the function of the main control unit 608. In that case, the main control unit 608 may not be provided.

The accelerator device 604 includes an accelerator pedal 604a included in the electric automobile 600 and an accelerator detection unit 604b that detects an operation amount (depression amount) of the accelerator pedal 604a. When the accelerator pedal 604a is operated by the user, the accelerator detection unit 604b detects the operation amount of the accelerator pedal 604a with reference to a state where the accelerator pedal 604a is not operated by the user. The detected operation amount of the accelerator pedal 604a is given to the main control unit 608.

The brake device 605 includes a brake pedal 605a included in the electric automobile 600 and a brake detection unit 605b that detects an operation amount (depression amount) of the brake pedal 605a by the user. When the user operates the brake pedal 605a, the operation amount is detected by the brake detection unit 605b. The detected operation amount of the brake pedal 605a is given to the main control unit 608. The rotation speed sensor 606 detects the rotation speed of the motor 602. The detected rotation speed is given to the main control unit 608.

As described above, the main controller 608 is given the state of charge of each battery cell 10, the amount of operation of the accelerator pedal 604a, the amount of operation of the brake pedal 605a, and the rotational speed of the motor 602. The main control unit 608 performs charge / discharge control of the battery cell group 100 and power conversion control of the power conversion unit 601 based on these pieces of information. For example, when starting and accelerating the electric automobile 600 based on the accelerator operation, power is supplied from the battery cell group 100 of the battery system 500 to the power conversion unit 601.

Further, the main control unit 608 calculates a rotational force (command torque) to be transmitted to the drive wheels 603 based on the given operation amount of the accelerator pedal 604a, and outputs a control signal based on the command torque to the power conversion unit 601. To give.

The power conversion unit 601 that has received the control signal converts the power supplied from the battery system 500 into power (drive power) necessary for driving the drive wheels 603. As a result, the driving power converted by the power converter 601 is supplied to the motor 602, and the rotational force of the motor 602 based on the driving power is transmitted to the driving wheels 603.

On the other hand, when the electric automobile 600 is decelerated based on the brake operation, the motor 602 functions as a power generator. In this case, the power conversion unit 601 converts the regenerative power generated by the motor 602 into power suitable for charging the battery cell group 100, and provides the battery cell group 100 with the power. Thereby, each battery cell 10 of the battery cell group 100 is charged.

(2-2) Effect In electric vehicle 600 as the electric vehicle according to the present embodiment, motor 602 is driven by electric power from battery system 500. When the driving wheel 603 is rotated by the rotational force of the motor 602, the electric automobile 600 moves. In this case, since the battery system 500 according to the first embodiment is used, the SOC that is the charged state of the battery cell 10 can be accurately estimated. Thereby, the running performance of the electric automobile 600 is improved.

(2-3) Other Moving Body The battery system 500 according to the first embodiment may be mounted on another moving body such as a ship, an aircraft, an elevator, or a walking robot.

A ship equipped with the battery system 500 includes, for example, a hull instead of the vehicle body 610 in FIG. 15, a screw instead of the drive wheel 603, an acceleration input unit instead of the accelerator device 604, and a brake device 605. Instead, a deceleration input unit is provided. The driver operates the acceleration input unit instead of the accelerator device 604 when accelerating the hull, and operates the deceleration input unit instead of the brake device 605 when decelerating the hull.

An aircraft equipped with the battery system 500 includes, for example, a fuselage instead of the vehicle body 610 in FIG. 15, a propeller instead of the driving wheel 603, an acceleration input unit instead of the accelerator device 604, and a brake device 605. Instead, a deceleration input unit is provided. Ships and aircraft do not have to include a deceleration input unit. In this case, when the driver operates the acceleration input unit to stop acceleration, the airframe is decelerated due to water resistance or air resistance.

An elevator equipped with the battery system 500 includes, for example, a saddle instead of the vehicle body 610 in FIG. 15, a lifting rope attached to the saddle instead of the driving wheel 603, and an acceleration input unit instead of the accelerator device 604. And a deceleration input unit instead of the brake device 605.

A walking robot equipped with the battery system 500 includes, for example, a trunk instead of the vehicle body 610 in FIG. 15, a foot instead of the drive wheel 603, an acceleration input unit instead of the accelerator device 604, and a brake device 605. A deceleration input unit is provided instead of.

In these moving bodies, the motor corresponds to the power source, the hull, gas, rod and trunk correspond to the main body, and the screw, propeller, lifting rope and foot correspond to the drive section. The power source receives electric power from the battery system 500 and converts the electric power into motive power, and the drive unit moves the moving main body portion with the motive power converted by the motive power source.

(2-4) Effects in Other Moving Body In the moving body according to the present embodiment, the electric power from battery system 500 is converted into motive power by the power source, and the drive unit moves the moving main body by the motive power. In this case, since the battery system 500 according to the first embodiment is used, the SOC that is the charged state of the battery cell 10 can be accurately estimated. Thereby, the moving performance of the moving body is improved.

(3) Power supply device A power supply device according to a third embodiment of the present invention will be described. The power supply device according to the present embodiment includes a battery system 500 according to the first embodiment.

(3-1) Configuration and Operation FIG. 16 is a block diagram showing a configuration of a power supply device according to the third embodiment. As illustrated in FIG. 16, the power supply device 700 includes a power storage device 710 and a power conversion device 720. The power storage device 710 includes a battery system group 711 and a controller 712. The battery system group 711 includes a plurality of battery systems 500 according to the first embodiment. Between the plurality of battery systems 500, the plurality of battery cells 10 may be connected to each other in parallel, or may be connected to each other in series.

The controller 712 is an example of a system control unit, and includes, for example, a CPU and a memory, or a microcomputer. The controller 712 is connected to the charging state estimation device 200 (FIG. 1) of each battery system 500. The charging state estimation device 200 of each battery system 500 calculates the charging state (for example, SOC) of each battery cell 10 and gives the calculated charging state to the controller 712. The controller 712 controls the power conversion device 720 based on the charging state of each battery cell 10 given from each charging state estimation device 200, thereby discharging or charging a plurality of battery cells 10 included in each battery system 500. Control related to

The power converter 720 includes a DC / DC (DC / DC) converter 721 and a DC / AC (DC / AC) inverter 722. The DC / DC converter 721 has input /

output terminals

721a and 721b, and the DC / AC inverter 722 has input /

output terminals

722a and 722b. The input / output terminal 721 a of the DC / DC converter 721 is connected to the battery system group 711 of the power storage device 710. The input / output terminal 721b of the DC / DC converter 721 and the input / output terminal 722a of the DC / AC inverter 722 are connected to each other and to the power output unit PU1. The input / output terminal 722b of the DC / AC inverter 722 is connected to the power output unit PU2 and to another power system. The power output units PU1, PU2 include, for example, outlets. For example, various loads are connected to the power output units PU1 and PU2. Other power systems include, for example, commercial power sources or solar cells. This is an external example in which power output units PU1, PU2 and another power system are connected to a power supply device.

The DC / DC converter 721 and the DC / AC inverter 722 are controlled by the controller 712, whereby the plurality of battery cells 10 included in the battery system group 711 are discharged and charged.

When the battery system group 711 is discharged, power supplied from the battery system group 711 is DC / DC (direct current / direct current) converted by the DC / DC converter 721, and further DC / AC (direct current / alternating current) conversion is performed by the DC / AC inverter 722. Is done.

The power DC / DC converted by the DC / DC converter 721 is supplied to the power output unit PU1. The power DC / AC converted by the DC / AC inverter 722 is supplied to the power output unit PU2. DC power is output to the outside from the power output unit PU1, and AC power is output to the outside from the power output unit PU2. The electric power converted into alternating current by the DC / AC inverter 722 may be supplied to another electric power system.

The controller 712 performs the following control as an example of control related to discharging of the plurality of battery cells 10 included in each battery system 500. At the time of discharging the battery system group 711, the controller 712 determines whether or not to stop discharging based on the charging state of each battery cell 10 given from each charging state estimation device 200 (FIG. 1), and based on the determination result. The power converter 720 is controlled. For example, when the SOC of any one of the plurality of battery cells 10 (FIG. 1) included in the battery system group 711 is smaller than a predetermined threshold value, the controller 712 stops discharging. Alternatively, the DC / DC converter 721 and the DC / AC inverter 722 are controlled so that the discharge current (or discharge power) is limited. The SOC threshold value of the battery cell 10 for stopping the discharge or limiting the discharge current (or discharge power) is set, for example, within a range of 20% to 30%. Thereby, overdischarge of each battery cell 10 is prevented.

On the other hand, when the battery system group 711 is charged, AC power supplied from another power system is AC / DC (AC / DC) converted by the DC / AC inverter 722, and further DC / DC (DC) is converted by the DC / DC converter 721. / DC) converted. When power is supplied from the DC / DC converter 721 to the battery system group 711, the plurality of battery cells 10 (FIG. 1) included in the battery system group 711 are charged.

The controller 712 performs the following control as an example of control related to charging of the plurality of battery cells 10 included in each battery system 500. When charging the battery system group 711, the controller 712 determines whether or not to stop charging based on the charging state of each battery cell 10 given from each charging state estimation device 200 (FIG. 1), and based on the determination result. The power converter 720 is controlled. For example, when the SOC of any one of the plurality of battery cells 10 included in the battery system group 711 becomes larger than a predetermined threshold, the controller 712 stops the charging or the charging current ( Alternatively, the DC / DC converter 721 and the DC / AC inverter 722 are controlled so that the charging power is limited. The SOC threshold value of the battery cell 10 for stopping charging or limiting the charging current (or charging power) is set, for example, within a range of 70% to 80%. Thereby, overcharge of each battery cell 10 is prevented.

(3-2) Effect In power supply device 700 according to the present embodiment, power conversion device 720 performs power conversion between the battery cell and the outside. A controller 712 as a system control unit controls the power conversion device 720 to perform control related to charging or discharging of the battery cell 10 of the battery system 500. Thereby, deterioration, overdischarge, and overcharge of the battery cell 10 can be prevented. Moreover, since the battery system 500 according to the first embodiment is used, the SOC that is the state of charge of the battery cell 10 can be accurately estimated. Therefore, the charge / discharge performance of the power supply device 700 is improved.

(3-3) Modification of Power Supply Device In the power supply device 700, the controller 712 may have the same function as that of the charge / discharge estimation device 200, instead of providing each battery system 500 with the charge / discharge estimation device 200. Further, instead of providing the current detection unit 201 in each battery system 500, a configuration in which one current detection unit 201 is provided in only one battery system 500 may be employed. In this case, the value of the detected current may be output from one current detection unit 201 to the charge state estimation device 200 of each battery system 500, or the charge / discharge estimation device 200 is not provided in each battery system 500. When the controller 712 has the function of the charge / discharge estimation apparatus 200, the current value detected by the controller 712 may be output from one current detection unit 201.

As long as power can be supplied between the power supply apparatus 700 and the outside, the power conversion apparatus 720 may include only one of the DC / DC converter 721 and the DC / AC inverter 722. Further, the power conversion device 720 may not be provided as long as power can be supplied between the power supply device 700 and the outside.

In the power supply device 700 of FIG. 16, a plurality of battery systems 500 are provided, but not limited to this, only one battery system 500 may be provided.

(4) Correspondence between each component of claim and each part of embodiment The following describes an example of a correspondence between each component of the claim and each part of the embodiment. It is not limited.

In the above embodiment, the battery cell 10 is an example of a battery cell, the charge state estimation device 200 is an example of a charge state estimation device, the storage unit 215 is an example of a storage unit, the internal resistance acquisition unit 211, The SOC acquisition unit 212, the data array storage unit 213, and the table update unit 214 are examples of processing units, and the SOC is an example of a charged state.

The electric automobile 600 is an example of an electric vehicle and a moving body, the motor 602 is an example of a motor and a power source, the driving wheel 603 is an example of a driving wheel and a driving unit, and the vehicle body 610 is an example of a moving main body. The power storage device 710 is an example of a power storage device, the power supply device 700 is an example of a power supply device, the controller 712 is an example of a system control unit, and the power conversion device 720 is an example of a power conversion device. .

As the constituent elements of the claims, various other elements having configurations or functions described in the claims can be used.

DESCRIPTION OF SYMBOLS 10 Battery cell 100 Battery cell group 200 Charging state estimation apparatus 201 Current detection part 202 Voltage detection part 203 Temperature detection part 205 Output part 211 Internal resistance acquisition part 212 SOC acquisition part 213 Data arrangement | sequence storage part 214 Table update part 215 Storage part 500 Battery System 600 Electric automobile 602 Motor 603 Driving wheel 610 Car body 700 Power supply device 710 Power storage device 712 Controller 720 Power conversion device

Claims

A battery cell;
A voltage detector for detecting a terminal voltage of the battery cell;
A temperature detector for detecting the temperature of the battery cell;
A charging state estimation device for estimating a charging state of the battery cell;
The state of charge estimating device is:
A storage unit for storing internal impedance information representing a relationship between the internal impedance and temperature of the battery cell;
A processing unit that estimates the state of charge of the battery cell based on the internal impedance information stored in the storage unit and updates the internal impedance information;
The processing unit is detected by the voltage detection unit in a first non-charge / discharge period in which the battery cell is not charged and discharged before a charge / discharge period in which the battery cell is charging or discharging. The first terminal voltage of the battery cell and the second terminal of the battery cell detected by the voltage detection unit in a second non-charging period in which the battery cell is not charged and discharged after the charging / discharging period. The charge state of the battery cell during the charge / discharge period is calculated based on the voltage, the current flowing through the battery cell during the charge / discharge period, and the terminal voltage of the battery cell detected by the voltage detection unit during the charge / discharge period And an internal battery cell in the charge / discharge period based on the calculated charge state in the charge / discharge period. A battery configured to calculate a impedance and update the internal impedance information stored in the storage unit based on the temperature detected by the temperature detection unit and the calculated internal impedance during the charge / discharge period. system.
The storage unit further stores charge state information representing a relationship between a charge state of the battery cell and an open-circuit voltage that is a terminal voltage when the battery cell is not charged and discharged and is in a steady state. ,
The processing unit acquires an open-circuit voltage corresponding to the calculated charge state in the charge / discharge period based on the charge state information stored in the storage unit, and flows to the battery cell in the charge / discharge period. The battery system according to claim 1, wherein an internal impedance of the battery cell is calculated based on a current, a terminal voltage of the battery cell in the charge / discharge period, and the calculated open circuit voltage.
The processing unit acquires a first charge state of the battery cell in the first non-charge / discharge period based on the first terminal voltage, and the second non-charge based on the second terminal voltage. The second charge state of the battery cell in the charge / discharge period is acquired, an integrated value of the current flowing through the battery cell in the charge / discharge period is calculated, and the acquired first and second non-charge / discharge periods 3. The battery system according to claim 1, wherein a charge state of the battery cell in the charge / discharge period is calculated based on the first and second charge states and the calculated integrated value.
When the current flowing through the battery cell during the charge / discharge period is constant, the processing unit is configured to perform a first charge state of the battery cell during the first non-charge / discharge period based on the first terminal voltage. And obtaining the second charge state of the battery cell in the second non-charge / discharge period based on the second terminal voltage, and obtaining the first and second non-charge / discharge periods. The charge state of the battery cell in the charge / discharge period is calculated based on the first and second charge states and the elapsed time from the start time of the charge / discharge period. The battery system described in.
The battery system according to claim 4, wherein the processing unit does not update the internal impedance information when a current flowing through the battery cell is not constant during the charge / discharge period.
A storage unit for storing internal impedance information representing the relationship between the internal impedance and temperature of the battery cell;
A processing unit that estimates the state of charge of the battery cell based on the internal impedance information stored in the storage unit and updates the internal impedance information;
The processing unit includes a first terminal of the battery cell in a first non-charge / discharge period in which the battery cell is not charged and discharged before a charge / discharge period in which the battery cell is charging or discharging. Charging the battery cell during the charge / discharge period based on a voltage and a second terminal voltage of the battery cell during a second non-charge period during which the battery cell is not charged and discharged after the charge / discharge period. The battery in the charge / discharge period is calculated based on the current flowing through the battery cell in the charge / discharge period, the terminal voltage of the battery cell in the charge / discharge period, and the calculated charge state in the charge / discharge period. Calculate the internal impedance of the cell, the temperature of the battery cell during the charge and discharge period and the calculation Wherein configured to update the internal impedance information, the device for estimating charged state stored in the storage unit based on the internal impedances.
A battery system according to any one of claims 1 to 5;
A motor driven by power from the battery system;
An electric vehicle comprising drive wheels that are rotated by the rotational force of the motor.
A battery system according to any one of claims 1 to 5;
A moving body,
A power source that converts electric power from the battery system into power for moving the moving main body;
A moving body comprising: a drive unit that moves the moving main body unit by power converted by the power source.
A battery system according to any one of claims 1 to 5;
And a system control unit that performs control related to charging or discharging of the battery cell of the battery system.
Can be connected to the outside,
The power storage device according to claim 9,
A power supply device comprising: a power conversion device that is controlled by the system control unit of the power storage device and performs power conversion between the battery cell of the battery system of the power storage device and the outside.