JP5692047B2 - Power storage system - Google Patents

Description

  The present invention relates to a power storage system that determines an operating state of a current breaker in a power storage block in which a plurality of power storage elements each having a current breaker are connected in parallel.

  In the assembled battery described in Patent Document 1, in a configuration in which a plurality of batteries are connected in parallel, a fuse is connected to each of the single cells connected in parallel. The fuse cuts off the current path by fusing when an excessive current flows. In the technique described in Patent Document 2, the operation of a current interrupt mechanism included in the battery is detected based on a change in the internal resistance of the battery.

JP 05-275116 A JP 2008-182779 A JP 2011-135657 A

  In a configuration in which a plurality of batteries are connected in parallel, the value of the current flowing through the battery in which the current breaker is not operating varies depending on the number of activations of the current breaker. Specifically, when the number of operation of the current breaker increases, the value of the current flowing through the battery where the current breaker is not operating increases, so the current load on the battery where the current breaker is not operating increases. . For this reason, in order to control charging / discharging of the battery, it is necessary to detect the operation of the current breaker. However, in the technique of Patent Document 2, the voltage behavior of the battery is monitored and compared with a reference voltage measured in advance. Therefore, there is a problem that the operation of the current breaker cannot be accurately detected.

  The battery characteristics vary depending on the environmental temperature, manufacturing variations, battery deterioration, and the like. For this reason, the voltage behavior when the current breaker is activated and the voltage behavior due to the change in battery characteristics cannot be properly identified, and the operation of the current breaker cannot be accurately detected.

  On the other hand, if the operation of the current breaker is detected, if the charging / discharging of the battery is restricted, it is possible to suppress an increase in the current load on the battery, but if the number of operation of the current breaker is not specified, Battery charge / discharge control cannot be performed efficiently. That is, only detecting the operating state of the current breaker may limit the charging / discharging of the battery excessively. Therefore, in order to prevent the charging / discharging of the battery from being excessively limited, it is necessary to know the number of operating current breakers. In the technique described in Patent Document 2, only the operating state of the current breaker is detected, and the number of operating current breakers cannot be specified.

The power storage system according to the first invention of the present application includes a plurality of power storage elements connected in parallel, and a plurality of power storage blocks connected in series, a temperature at which the temperature of the power storage block and the ambient temperature of the power storage element are detected. A sensor, and a controller that determines a state of each power storage block using a temperature change amount of the power storage element according to a temperature difference between the ambient temperature and the detected temperature of the power storage block . Each power storage element has a current breaker that blocks a current path inside the power storage element. The controller sets the remaining power storage elements connected in parallel to the power storage elements in which the current circuit breakers are in the cut-off state with respect to the current value flowing through the power storage elements in the power storage block in which the current circuit breakers of all the power storage elements are not in the cut-off state. Based on the relationship in which the value of the flowing current increases in accordance with the number of breaks of the current breaker , the first temperature change amount of the storage element according to the current flowing through the storage block is the current of all the storage elements connected in parallel. Unlike the second temperature change amount of the power storage element according to the current flowing through the power storage block in which the circuit breaker is not in the cutoff state, the temperature change amount with respect to the second temperature change amount at which the first temperature change amount is 1 or more If you have a rate of increase, circuit breakers of the power storage device included in the power storage block is detected to be in a cutoff state.

  According to the first invention of the present application, it is possible to detect whether or not the current breaker is activated based on a temperature change of the storage element. That is, when the current breaker of the power storage elements connected in parallel is activated, the current concentrates on the remaining power storage elements where the current breaker is not activated, and the current flowing through the remaining power storage elements where the current breaker is not activated The value increases. For this reason, the amount of heat generated by the storage element increases as the value of the current flowing through the storage element in which the current breaker is not operating increases, and the storage element in the storage block in which the current breaker of the storage element is activated The amount of temperature change between the storage elements of the storage blocks in which the current breakers of all of the storage elements connected in parallel are not operating is different. Therefore, with reference to the temperature change amount of the storage element corresponding to the current flowing through the storage block in which the current breaker is not activated, the storage element according to the current flowing through the storage block based on the detected temperature detected by the temperature sensor is used. When the temperature change amount is different, the operating state of the current breaker can be detected.

  The controller uses a current sensor from a current-temperature change map that preliminarily defines a temperature change amount of the power storage element according to a current value flowing through a power storage block in which each current breaker of all power storage elements connected in parallel is not in a cutoff state. By calculating the temperature change amount corresponding to the detected current flowing through the power storage block detected by the second temperature change amount, and comparing the first temperature change amount and the second temperature change amount based on the current-temperature change map, It can be configured to detect whether or not the current breaker is activated.

The controller acquires, as the second temperature change amount, the temperature change amount of the power storage element corresponding to the current flowing in the second power storage block different from the first power storage block corresponding to the first temperature change amount. By comparing the temperature change amounts of the respective storage elements, it is possible to detect whether or not the current breaker is activated.

The controller obtains the temperature change amount of the electricity storage element according to the current flowing through the electricity storage block in time series, and uses the current temperature change amount as the first temperature change amount and the past temperature change amount as the second temperature change amount. By comparing the current temperature change amount and the past temperature change amount of the power storage element of the power storage block, it can be configured to detect whether or not the current breaker is activated.

  The controller calculates the first internal resistance of the power storage element at the first time by using the first detected current of the current sensor at the first time corresponding to the past temperature change amount and the past temperature change amount, The second internal resistance of the storage element at the second time is calculated using the second detected current of the current sensor at the second time after a fixed time has elapsed from the first time corresponding to the temperature change and the current temperature change. When the first internal resistance and the second internal resistance corresponding to each temperature change amount of the power storage element at the first time and the second time are different, the current breaker of the power storage element included in the power storage block is cut off. It can be configured to detect that it is in a state.

The controller uses a rate of increase of the first temperature change amount with respect to the second temperature change amount between the first temperature change amount and the second temperature change amount, and the current breaker included in the power storage block is in a cut-off state. The number of power storage elements can be specified .

  The current breaker is a fuse that cuts off the current path by fusing, a PTC element that cuts off the current path due to an increase in resistance due to a temperature rise, or a deformed according to an increase in internal pressure of the storage element, and cuts off the current path A current cutoff valve can be used.

A second invention of the present application is a method for determining a state of a storage block in a storage system configured by connecting a plurality of storage blocks connected in parallel with a plurality of storage elements each having a current breaker that cuts off a current path. Then, the temperature of the electricity storage block and the ambient temperature of the electricity storage element are detected by a temperature sensor, and the temperature change amount of the electricity storage element according to the temperature difference between the ambient temperature and the detected temperature of the electricity storage block is calculated. The current breaker flows to the remaining power storage elements connected in parallel to the power storage elements in the interrupted state with respect to the current value flowing to the power storage elements of the power storage blocks in which the current circuit breakers of all the power storage elements are not in the disconnected state. Based on the relationship in which the current value increases according to the number of interruptions of the current breaker , the first temperature change amount of the electricity storage element according to the current flowing through the electricity storage block is the current interruption of all the electricity storage elements connected in parallel. The temperature change with respect to the second temperature change amount that is different from the second temperature change amount of the power storage element according to the current flowing through the power storage block that is not in the shut-off state, and the first temperature change amount is the cut-off number of 1 or more. If you have a rate of increase in quantity, the current breaker of the power storage device included in the power storage block is detected to be in a cutoff state. Also in the second invention of the present application, the same effect as that of the first invention of the present application can be obtained.

It is a figure which shows the structure of a battery system. It is a figure which shows the structure of an assembled battery. It is a figure which shows the structure of a cell. It is an example which shows the relationship between the electric current which flows into a single battery, and a temperature change. It is a flowchart which shows the electric circuit breaker action | operation detection process of Example 1. FIG. It is a modification of the electric circuit breaker action | operation detection process of Example 1. FIG. It is a flowchart which shows the process of the charge / discharge control after the action | operation detection of the current circuit breaker of Example 1 is detected. It is a flowchart which shows the electric circuit breaker action | operation detection process of Example 2. FIG. It is a flowchart which shows the electric circuit breaker action | operation detection process of Example 3.

  Examples of the present invention will be described below.

Example 1
A battery system (corresponding to a power storage system) that is Embodiment 1 of the present invention will be described with reference to FIG. FIG. 1 is a diagram illustrating a configuration of a battery system. The battery system of this embodiment is mounted on a vehicle.

  Vehicles include hybrid cars and electric cars. The hybrid vehicle includes an engine or a fuel cell as a power source for running the vehicle in addition to the assembled battery described later. The electric vehicle includes only an assembled battery described later as a power source for running the vehicle.

  A system main relay SMR-B is provided on the positive line PL connected to the positive terminal of the battery pack 10. System main relay SMR-B is switched between ON and OFF by receiving a control signal from controller 40. A system main relay SMR-G is provided on the negative electrode line NL connected to the negative electrode terminal of the assembled battery 10. System main relay SMR-G is switched between on and off by receiving a control signal from controller 40.

  A system main relay SMR-P and a current limiting resistor R are connected in parallel to the system main relay SMR-G. System main relay SMR-P and current limiting resistor R are connected in series. System main relay SMR-P is switched between on and off by receiving a control signal from controller 40. The current limiting resistor R is used to suppress an inrush current from flowing when the assembled battery 10 is connected to a load (specifically, a booster circuit 32 described later).

  When connecting the assembled battery 10 to a load, the controller 40 switches the system main relays SMR-B and SMR-P from off to on. As a result, a current can flow through the current limiting resistor R, and an inrush current can be suppressed.

  Next, the controller 40 switches the system main relay SMR-P from on to off after switching the system main relay SMR-G from off to on. Thereby, connection of the assembled battery 10 and load is completed, and the battery system shown in FIG. 1 will be in a starting state (Ready-On). On the other hand, when cutting off the connection between the assembled battery 10 and the load, the controller 40 switches the system main relays SMR-B and SMR-G from on to off. Thereby, the operation of the battery system shown in FIG. 1 is stopped.

  The booster circuit 32 boosts the output voltage of the assembled battery 10 and outputs the boosted power to the inverter 33. Further, the booster circuit 32 can step down the output voltage of the inverter 33 and output the lowered power to the assembled battery 10. The booster circuit 32 operates in response to a control signal from the controller 40. In the battery system of this embodiment, the booster circuit 32 is used, but the booster circuit 32 may be omitted.

  The inverter 33 converts the DC power output from the booster circuit 32 into AC power, and outputs the AC power to the motor / generator 34. The inverter 33 converts AC power generated by the motor / generator 34 into DC power and outputs the DC power to the booster circuit 32. As the motor generator 34, for example, a three-phase AC motor can be used.

  Motor generator 34 receives AC power from inverter 33 and generates kinetic energy for running the vehicle. When the vehicle is driven using the output power of the assembled battery 10, the kinetic energy generated by the motor / generator 34 is transmitted to the wheels.

  When the vehicle is decelerated or stopped, the motor generator 34 converts kinetic energy generated during braking of the vehicle into electrical energy (AC power). The inverter 33 converts AC power generated by the motor / generator 34 into DC power and outputs the DC power to the booster circuit 32. The booster circuit 32 outputs the electric power from the inverter 33 to the assembled battery 10. Thereby, regenerative electric power can be stored in the assembled battery 10.

  FIG. 2 shows the configuration of the assembled battery 10. The assembled battery 10 has a plurality of battery blocks (corresponding to power storage blocks) 11 connected in series. By connecting a plurality of battery blocks 11 in series, the output voltage of the assembled battery 10 can be secured. Here, the number of battery blocks 11 can be appropriately set in consideration of the voltage required for the assembled battery 10.

  Each battery block 11 has a plurality of single cells (corresponding to power storage elements) 12 connected in parallel. By connecting a plurality of single cells 12 in parallel, the full charge capacity of the battery block 11 (the assembled battery 10) can be increased, and the distance when the vehicle is driven using the output of the assembled battery 10 can be increased. it can. The number of single cells 12 constituting each battery block 11 can be appropriately set in consideration of the full charge capacity required for the assembled battery 10.

  Since the plurality of battery blocks 11 are connected in series, an equal current flows through each battery block 11. In each battery block 11, a plurality of unit cells 12 are connected in parallel, so that the current value flowing through each unit cell 12 is the current value flowing through the battery block 11 by the number of unit cells 12 constituting the battery block 11. The current value is divided by (total). Specifically, when the total number of single cells 12 constituting the battery block 11 is N and the current value flowing through the battery block 11 is Is, the current value flowing through each single cell 12 is Is / N. . In this embodiment, it is assumed that the internal resistance does not vary among the plurality of single cells 12 constituting the battery block 11.

  As the unit cell 12, a secondary battery such as a nickel metal hydride battery or a lithium ion battery can be used. An electric double layer capacitor (capacitor) can be used instead of the secondary battery. For example, as the single battery 12, a 18650 type battery can be used. The 18650 type battery is a so-called cylindrical battery, which has a diameter of 18 [mm] and a length of 65.0 [mm]. In a cylindrical battery, a battery case is formed in a cylindrical shape, and a power generation element for charging and discharging is accommodated in the battery case. The configuration of the power generation element will be described later.

  As shown in FIG. 3, the unit cell 12 includes a power generation element 12 a and a current breaker 12 b. The power generation element 12 a and the current breaker 12 b are accommodated in a battery case that constitutes the exterior of the unit cell 12. The power generation element 12a is an element that performs charging and discharging, and includes a positive electrode plate, a negative electrode plate, and a separator disposed between the positive electrode plate and the negative electrode plate. The positive electrode plate includes a current collector plate and a positive electrode active material layer formed on the surface of the current collector plate. The negative electrode plate has a current collector plate and a negative electrode active material layer formed on the surface of the current collector plate. The positive electrode active material layer includes a positive electrode active material and a conductive agent, and the negative electrode active material layer includes a negative electrode active material and a conductive agent.

  When a lithium ion secondary battery is used as the single battery 12, for example, the current collector plate of the positive electrode plate can be made of aluminum, and the current collector plate of the negative electrode plate can be made of copper. As the positive electrode active material, for example, LiCo1 / 3Ni1 / 3Mn1 / 3O2 can be used, and as the negative electrode active material, for example, carbon can be used. An electrolyte solution is infiltrated into the separator, the positive electrode active material layer, and the negative electrode active material layer. Instead of using the electrolytic solution, a solid electrolyte layer may be disposed between the positive electrode plate and the negative electrode plate.

  The current breaker 12b is used to cut off the current path inside the unit cell 12. That is, when the current breaker 12b operates, the current path inside the unit cell 12 is cut off. For example, a fuse, a PTC (Positive Temperature Coefficient) element, or a current cutoff valve can be used as the current breaker 12b. These current breakers 12b can be used individually or in combination.

  The fuse as the current breaker 12b is blown according to the current flowing through the fuse. By blowing the fuse, the current path inside the unit cell 12 can be mechanically interrupted. Thereby, it can prevent that an excessive electric current flows into the electric power generation element 12a, and can protect the cell 12 (electric power generation element 12a). The fuse as the current breaker 12b may be accommodated in the battery case or may be arranged outside the battery case. Even when a fuse is disposed outside the battery case, the fuse is provided for each unit cell 12.

  The PTC element as the current breaker 12b is arranged in the current path of the unit cell 12, and increases the resistance according to the temperature rise of the PTC element. When the current flowing through the PTC element increases, the temperature of the PTC element rises due to Joule heat. As the resistance of the PTC element increases as the temperature of the PTC element rises, current can be cut off in the PTC element. Thereby, it can prevent that an excessive electric current flows into the electric power generation element 12a, and can protect the cell 12 (electric power generation element 12a).

  The current cut-off valve as the current breaker 12b is deformed in accordance with the increase in the internal pressure of the unit cell 12, and can cut off the current path inside the unit cell 12 by breaking the mechanical connection with the power generation element 12a. it can. The inside of the unit cell 12 is in a sealed state, and when gas is generated from the power generation element 12a due to overcharging or the like, the internal pressure of the unit cell 12 increases. When gas is generated from the power generation element 12a, the unit cell 12 (power generation element 12a) is in an abnormal state. The mechanical connection with the power generation element 12a can be broken by deforming the current cutoff valve in response to the increase in the internal pressure of the unit cell 12. Thereby, it can block | prevent that charging / discharging electric current flows into the electric power generation element 12a in an abnormal state, and can protect the cell 12 (electric power generation element 12a).

  The monitoring unit 20 shown in FIG. 1 detects the voltage of each battery block 11 and outputs the detection result to the controller 40. The current sensor 31 detects the value of the current flowing through the assembled battery 10 and outputs the detection result to the controller 40. For example, when the assembled battery 10 is being discharged, a positive value can be used as the current value detected by the current sensor 31. Further, when the battery pack 10 is being charged, a negative value can be used as the current value detected by the current sensor 31. The current sensor 31 only needs to be able to detect the value of the current flowing through the assembled battery 10 and can be provided not on the positive electrode line PL but on the negative electrode line NL. A plurality of current sensors 31 can also be used.

  The temperature sensor 21 is provided in each battery block 11, detects the temperature of the battery block 11 and the environmental temperature of the entire plurality of battery blocks 11, and outputs each detection result to the controller 40. For example, as shown in FIG. 2, the ambient temperature is the temperature on the intake side where cooling air such as outside air flows into the assembled battery 10 in the cooling structure that cools the assembled battery 10 including the intake duct 13 and the exhaust duct 14. The ambient temperature of the battery block 11 (unit cell 12). In this embodiment, the temperature sensor 21 detects the temperature on the inflow path between the intake duct 13 and the assembled battery 10 as the environmental temperature. In addition, you may provide a temperature sensor separately and may detect the temperature of the battery block 11 and environmental temperature with a separate temperature sensor.

  The controller 40 has a built-in memory 41, and the memory 41 stores a program for operating the controller 40 and specific information. The memory 41 can also be provided outside the controller 40.

  Processing in the battery system of the present embodiment will be described. In the present embodiment, the operation of each current breaker 12b of each of the battery blocks 11 including a plurality of single cells 12 including current breakers 12b connected in parallel is detected, and a plurality of batteries included in one battery block 11 are included. The number of the unit cells 12 in which the current breaker 12b is operating, that is, the number of operations of the current breaker 12b is specified (estimated). The specified number of activations of the current breaker 12b is used for charge / discharge control.

  In the present embodiment, using the temperature information of the single cells 12 in the battery block 11, the presence or absence of the operation of the current breaker 12b is detected. As described above, when the total number of the unit cells 12 constituting the battery block 11 is N and the current value flowing through the battery block 11 is Is, the current value flowing through each unit cell 12 is Is / N. When the current breaker 12b is activated, the number of the single cells 12 through which the current flows is reduced by the number of the single cells 12 in which the current breaker 12b is activated. For this reason, a current concentrates on the unit cell 12 in which the current breaker 12b is not activated, and a flowing current value increases.

  Since the calorific value of the single cell 12 increases when the value of the current flowing through the single cell 12 in which the current breaker 12b in the battery block 11 is not activated increases, the current breakers of all the plural single cells 12 connected in parallel Each of the single cells 12 in which 12b is not activated and the remaining single cells 12b connected in parallel to the single cell 12 in which the current breaker 12b of at least one or more single cells 12 is activated are not activated. A difference in temperature is generated between the battery 12 and the heat generation amount.

For example, assuming that the total number of the single cells 12 in one battery block 11 is N, the internal resistance R of each single cell 12 and the current value flowing through the battery block 11 is I (Is), the calorific value of the single cell 12 is as follows: It can be calculated by the following formula 1.
(Formula 1) Q = (I / N) ² × R
If the thermal resistance θ from the unit cell 12 to the outside is given, the temperature change amount ΔT of the unit cell 12 with respect to the calorific value of Equation 1 is
(Formula 2) ΔT = Q × θ = (I / N) ² × R × θ
It becomes.

  The temperature change amount ΔT due to the current flowing through the unit cell 12 is a temperature increase value resulting from the heat generation amount of Equation 1 with respect to the environmental temperature around the battery block 11. Note that the thermal resistance θ is a temperature change (rise) amount with respect to a heat generation amount per unit time. The internal resistance R and the thermal resistance θ of each unit cell 12 can be the same value.

Here, out of the N unit cells 12 of one battery block 11, when the number of the unit cells 12 in which the current breaker 12b is activated is x, the remaining unit cells 12 in which the current breaker 12b is not activated. Since the value of the current flowing in the current cell is I / (N−x), the temperature change ΔT ′ with respect to the environmental temperature of the remaining unit cell 12 where the current breaker 12b is not operating is
(Formula 3) ΔT ′ = (I / (N−x)) ² × R × θ
As can be understood from Equation 3, the amount of heat generated by the remaining single cells 12 connected in parallel to the single cell 12 in which the current breaker 12b is operating depends on the number of operations of the current breaker 12b according to x. To increase. When a current of I / (N−x) flows to each remaining unit cell 12, the temperature change amount of the unit cell 12 becomes ΔT ′, and the current out of the N unit cells 12 of one battery block 11. When the circuit breaker 12b is activated, the temperature of the remaining unit cells 12 increases according to the number of activated current breakers 12b, and is higher than the unit cell 12 of the battery block in which no current breaker 12b is activated. An increase will be indicated (ΔT ′> ΔT).

FIG. 4 is a diagram (current-temperature rise map) showing the relationship between the current flowing through the cell 12 and the temperature rise. The vertical axis is temperature change amount [Delta] T, the horizontal axis represents the current I ^2. In the example of FIG. 4, the horizontal axis is represented by the square of the current I from the relationship shown in the above formulas 2 and 3.

In FIG. 4, the solid line indicates the temperature change ΔT of the unit cell 12 of the battery block 11 in which the current breaker 12b is not operated, and the dotted line is the remaining battery block 11 in the state in which the current breaker 12b is activated. The temperature change amount ΔT ′ of the unit cell 12 in which the current breaker 12b is not activated is shown. As shown in FIG. 4, the relationship between ΔT and ΔT ′ can be expressed as follows from the relationship of Equations 2 and 3 above.
(Formula 4) ΔT ′ = (I / (N−x)) ² × R × θ = (N / (N−x) ) ² × (I / N) ² × R × θ
= (N / (N−x) ) ² ΔT

As can be understood from Equation 4, the temperature change amount ΔT ′ is (N / (N−x) ) ² times the temperature change amount ΔT. For this reason, the amount of temperature change of the single battery 12 of the battery block 11 in which the current breaker 12b is not activated and the remaining current breaker 12b of the battery block 11 in the state in which the current breaker 12b is activated are not activated. 12 has a rate of increase (rate of change) based on (N / (N−x) ) ² corresponding to the number of actuations x of the current breaker 12b shown in the following formula 5. .
(Formula 5) ΔT ′ / ΔT = (N / (N−x) ) ²

Furthermore, when Formula 5 is expanded with the operating number x,
(Formula 6)
It becomes. According to Equations 5 and 6, the current breaker 12b of the battery block 11 in the state where the current breaker 12b is activated with respect to the temperature change amount of the unit cell 12 of the battery block 11 where the current breaker 12b is not activated is activated. The operating number x can be calculated from the rate of increase in the temperature change amount of the remaining single cells 12. The current breaker is caused by the fact that the current flowing through the remaining cells 12 that are not connected to the current breaker 12b that is connected in parallel to the cells 12 in which the current breaker 12b is activated increases according to the number of operations x. The amount of heat generated by the remaining cells 12 that are not operating 12b increases, and the temperature change amount ΔT ′ of the battery block 11 relative to the reference temperature change amount ΔT of the cells 12 of the battery block 11 that is not operating the current breaker 12b. The rate of increase of increases with the number of operations x.

  Thus, the current breaker 12b of the battery block 11 in the state in which the current breaker 12b is activated is not activated with respect to the temperature change amount ΔT of the single cell 12 of the battery block 11 in which the current breaker 12b is not activated. The temperature change amount ΔT ′ of the remaining single cells 12 indicates a predetermined rate of increase according to the number of operations. Therefore, if the current breaker 12b is not activated, the detected temperature detected by the temperature sensor 21 is used. The temperature change amount of the unit cell 12 according to the current flowing through the battery block 11 is based on the reference temperature of the unit cell 12 according to the current flowing through the battery block 11 in which the current breakers 12b of all the unit cells 12 are not in operation. Should be the same as the amount of change.

  Therefore, if the temperature change of the cell 12 according to the electric current which flows into the battery block 11 based on the detected temperature detected by the temperature sensor 21 is monitored and is different from the reference temperature increase value, the current breaker of the cell 12 12b is in operation, the battery in which the current breaker 12b of the battery cell 12 is in operation is compared with the temperature change amount of the battery cell 12 detected by the temperature sensor 21 and the reference temperature change amount. The operating state of the current breaker 12 of the block 11, that is, the unit cell 12 of the battery block 11 can be detected.

  Then, the current interruption in the battery block 11 in which the current breaker 12b of the single battery 12 is operated is determined from the rate of increase corresponding to the number of operations x between the temperature change amount of the single battery 12 and the reference temperature change amount. The number of actuations x of the vessel 12b can be calculated.

  Here, the difference between the temperature change amount of the unit cell 12 and the reference temperature change amount according to the current flowing in the battery block 11 based on the detected temperature detected by the temperature sensor 21 is based on the equation 5 or the equation 6. It can be represented by the number of actuations x of the circuit breaker 12b.

  For example, from the viewpoint of detecting the operating state of the current breaker 12b, the relationship between the rate of increase in the temperature change amount of the unit cell 12 with respect to the reference temperature change amount and the operation number x is an increase that satisfies x ≧ 1 in Expression 6. When there is a rate relationship, in the battery block 11 in which the current breaker 12b of at least one unit cell 12 is activated, heat is generated according to the current value flowing in each remaining unit cell 12 in which the current breaker 12b is not activated. The temperature rise value based on the amount is different from the reference temperature change amount, and it can be detected that the current breaker 12b of the unit cell 12 is operating in the battery block 11.

  That is, by determining whether the rate of increase in the temperature change amount of the single battery 12 with respect to the reference temperature change amount is an increase rate at which the operation number x in the battery block 11 satisfies 1 or more, in other words, the reference temperature change The current flowing through the battery block 11 based on the detected temperature detected by the temperature sensor 21 is determined by determining whether or not the operation number x calculated from the rate of increase in the temperature change amount of the single battery 12 with respect to the amount is 1 or more. Accordingly, it can be determined that the temperature change amount of the single battery 12 and the reference temperature change amount according to the difference are different, and the battery block 11 detects that the current breaker 12b of the single battery 12 is operating. Can do.

  Accordingly, the temperature change of the single cells 12 of the battery block 11 is monitored, and the single cells based on the reference temperature change amount ΔT of the single cells 12 in which all the current breakers 12 b are not operating and the detected temperature detected by the temperature sensor 21. From the temperature change amount ΔT ′ of 12, the reference temperature change amount ΔT and the temperature change amount are calculated using the method of calculating the operation number x based on the rate of increase due to the operation of the current breaker 12 b shown in Equations 5 and 6. The difference from ΔT ′ is detected, and at the same time as detecting whether or not the current breaker 12b of the unit cell 12 is operating in the battery block 11, the operating number x can be calculated.

  Note that the rate of increase is created in advance as numerical information (including numerical range information) for each operating number x, and, for example, in Equation 5, the operating number is 1 or 2 based on the relationship between the reference temperature change amount and the operating number. The rate of increase in each of the three,... Is calculated in advance, the rate of increase in the temperature change of the cell 12 with respect to the reference temperature change is matched with each numerical value information, and the current of the cell 12 in the battery block 11 is matched. You may make it calculate the operating state of the circuit breaker 12b, and its operation | movement number x.

  In the current breaker operation detection process of the present embodiment, the current breaker 12b indicated by the solid line in FIG. 4 is activated in the battery block 11 in which the N unit cells 12 including the current breaker 12b are connected in parallel to each other. A current-temperature rise map of the unit cell 12 in the battery block 11 in a state where the battery block 11 is not in advance is created in advance, and a temperature change amount ΔT1 which is a difference between the detected temperature T1 of the battery block 11 and the environmental temperature Ta acquired by the temperature sensor 21; A reference temperature change amount ΔT acquired from a current-temperature increase map corresponding to the current value detected by the current sensor 31 is compared, and a difference (difference) in the temperature change amount based on the increase rate according to the operation number x is obtained. When it has occurred, it is detected in the battery block 11 that the current breaker 12b of the cell 12 is operating.

  In the present embodiment, the temperature of the unit cell 12 of each battery block 11 can be monitored using the detected temperature of the battery block 11 detected by the temperature sensor 21. That is, since the calorific values of the single cells 12 connected in parallel are the same, the temperature sensor 21 detects the detected temperature of the battery block 11 as the temperature of the single cell 12 according to the current value flowing through the battery block 11. can do. Therefore, a temperature change amount that is a temperature rise value of the single cell 12 is acquired from the temperature (environment temperature) around the single cell 12 (battery block 11) detected by the temperature sensor 21 and the detected temperature of the battery block 11. can do.

  Further, the current-temperature rise map shown in FIG. 4 can be configured to hold a different map for each environmental temperature. Since the internal resistance R of the unit cell 12 varies depending on the ambient temperature of the battery block 11, that is, the environmental temperature Ta, a plurality of current-rise change maps are created and held for each environmental temperature Ta. A current-temperature increase map corresponding to the environmental temperature Ta detected by the temperature sensor 21 is appropriately selected, and a reference temperature change value ΔT corresponding to the detection value of the current sensor 31 can be acquired. Each current-temperature rise map can be stored in the memory 41.

  FIG. 5 is a flowchart of the current breaker operation detection process. The process shown in FIG. 5 is performed at a predetermined cycle and executed by the controller 40. The process shown in FIG. 5 is performed on each battery block 11.

  In step S <b> 101, the controller 40 detects the detected temperature T <b> 1 and the environmental temperature Ta of the single battery 12 of each battery block 11, and the current value I (current value flowing through each battery block 11) flowing through the assembled battery 10 detected by the current sensor 31. ) To get. Information about the acquired detected temperature T1, environmental temperature Ta, and current value I is stored in the memory 41.

  In step S102, the controller 40 calculates the temperature change amount ΔT1 of the single battery 12. ΔT1 can be obtained by subtracting the environmental temperature Ta from the detected temperature T1.

  In step S <b> 103, the controller 40 acquires the reference temperature change amount ΔT corresponding to the acquired current value I from the current-temperature increase map corresponding to the environmental temperature Ta detected by the temperature sensor 21. The temperature change value ΔT corresponding to the square of the current value I acquired as in the example of FIG. 4 can be calculated as the reference temperature change value.

  In consideration of the fact that the current value I varies depending on the load (for example, the motor / generator 34), for example, the temperature sensor 21 uses a battery to obtain the reference temperature change ΔT from the current-temperature rise map. Instead of the detection current value at a predetermined time point when the battery temperature T of the block 11 is detected, a moving average of the squares of the current value I obtained in a past fixed period based on the time point at which the battery temperature T is detected is used. be able to.

  In step S104, the controller 40 compares the temperature change amount ΔT1 of the single cell 12 based on the detected temperature T1 with the reference temperature change amount ΔT acquired from the current-temperature rise map. If ΔT1 = ΔT, the controller 40 performs step S107. Then, it is detected that the current breaker 12b of the unit cell 12 included in the corresponding battery block 11 is not activated.

  On the other hand, if it is determined that ΔT1 = ΔT is not satisfied in step S104, that is, if it is determined that ΔT1> ΔT, the controller 40 proceeds to step S105, and the current breaker of the unit cell 12 included in the corresponding battery block 11 is determined. It is detected that 12b is operating.

  The controller 40 further specifies the operation number x of the current breaker 12b in the battery block 11 with respect to the detection result indicating that the current breaker 12b is activated in step S105. In step S106, the controller 40 calculates the operation number x of the current breaker 12b from the above equation 6 using ΔT1 and ΔT, and specifies the number m (= x) of the unit cells 12 whose current path is interrupted. To do.

  FIG. 6 is a modified example of the current breaker operation detection process. From the reference temperature change amount ΔT and the temperature change amount ΔT1 based on the detected temperature T1, an increase rate (change rate) due to the operation of the current breaker 12b is obtained. This is an example of processing for detecting the operation of the current breaker 12b by using the calculation method of the number of operations x based on the above. In FIG. 6, the same processes as those in FIG. 5 are denoted by the same reference numerals, description thereof will be omitted, and differences from FIG. 5 will be mainly described.

  In step S1104, the controller 40 calculates the rate of increase of the temperature change amount ΔT1 with respect to the reference temperature change amount ΔT using the temperature change amount ΔT1 and the reference temperature change amount ΔT based on the detected temperature T1 acquired through steps S101 to S103. Then, the operation number x based on the rate of increase due to the operation of the current breaker 12b is calculated (Formula 6).

  In step S1105, the controller 40 determines whether or not the calculated operation number x is 1 or more (whether or not the operation number x is an increase rate that satisfies 1 or more). As a result of the determination, if it is determined that the calculated operation number x is 1 or more, the controller 40 proceeds to step S1106, and the current breaker 12b of the unit cell 12 included in the corresponding battery block 11 is operated. Is detected, and the calculated number of actuations x is used as the number of interruptions m (= x) of the unit cells 12 whose current path is interrupted in the battery block 11 in which the operation state of the current breaker 12b is detected. ).

  On the other hand, when it is determined that the operation number x calculated in step S1105 is less than 1, the controller 40 proceeds to step S107, and the current breaker 12b of the unit cell 12 included in the corresponding battery block 11 is activated. Detect if not.

  FIG. 7 is a flowchart showing the charge / discharge control process after the current breaker operation detection process shown in FIGS. 5 and 6. The charge / discharge control process shown in FIG. 7 is executed by the controller 40.

  After specifying the cutoff number m, the controller 40 can control charging / discharging of the assembled battery 10 based on the cutoff number m.

  As described above, in the battery block 11, when the current breaker 12b is activated, no current flows through the unit cell 12 having the current breaker 12b in the activated state. Further, the remaining unit cells 12 connected in parallel with the unit cells 12 having the current circuit breaker 12b in the operating state have extra current that is scheduled to flow to the unit cells 12 having the current circuit breaker 12b in the operating state. Will flow. Here, when the current value Is flowing through the assembled battery 10 (battery block 11) is not limited, the current value flowing through the remaining single cells 12 is Is / (N−m). Since the value of “N−m” is smaller than the value of “N”, the value of the current flowing through the remaining unit cells 12 increases.

  When the value of the current flowing through the unit cell 12 increases, in other words, when the current load on the unit cell 12 increases, high-rate deterioration may occur. Further, when a lithium ion secondary battery is used as the single battery 12, lithium may be deposited. Furthermore, when the value of the current flowing through the unit cell 12 increases, the current breaker 12b is likely to operate.

  In step S301, the controller 40 proceeds to step S302 when the operation of the current breaker 12b is detected in the current breaker operation detection shown in FIG. 5 and FIG. The current command value for controlling charging / discharging of the battery pack 10 can be determined based on the above. Specifically, the controller 40 can reduce the charge / discharge current of the assembled battery 10 as the current command value increases as the number of interruptions m increases. The controller 40 can set the current command value based on the following formula (7).

(Expression 7) Is (2) = Is (1) × (N−m) / N

  In Expression 7, Is (1) is a current command value before the current breaker 12b is activated, and Is (2) is a current command value after the current breaker 12b is activated. As can be seen from Expression 7, since the value of “(N−m) / N” is a value smaller than 1, the current command value Is (2) is smaller than the current command value Is (1).

  In step S303, the controller 40 can control charging / discharging of the assembled battery 10 based on the current command value Is (2). Specifically, the controller 40 reduces the upper limit power that allows charging of the assembled battery 10 or decreases the upper limit power that allows discharging of the assembled battery 10 based on the current command value Is (2). . When lowering the upper limit power, the upper limit power before being lowered can be multiplied by a value of “(N−m) / N”. By reducing the upper limit power that allows charging / discharging of the assembled battery 10, the value of the current flowing through the assembled battery 10 (unit cell 12) can be limited.

  When the interruption number m is “N”, the current breaker 12b is in operation in all the unit cells 12 constituting the battery block 11, so that no current can flow through the battery pack 10. For this reason, when the shut-off number m is “N”, the controller 40 can prevent the assembled battery 10 from being charged / discharged. Specifically, the controller 40 can set the upper limit power that allows charging and discharging of the assembled battery 10 to 0 [kW]. Further, the controller 40 can turn off the system main relays SMR-B, SMR-G, and SMR-P.

  The charge / discharge control of the assembled battery 10 is performed not only when the battery system shown in FIG. 1 is activated, but also when the power of the external power source is supplied to the assembled battery 10 or when the power of the assembled battery 10 is supplied to an external device. It can also be done while feeding. The external power source is a power source provided outside the vehicle, and for example, a commercial power source can be used as the external power source. The external device is an electronic device arranged outside the vehicle, and is an electronic device that operates by receiving electric power from the assembled battery 10. As the external device, for example, a home appliance can be used.

  When supplying power from the external power source to the assembled battery 10, a charger can be used. The charger can convert AC power from an external power source into DC power and supply the DC power to the assembled battery 10. The charger can be mounted on the vehicle or can be provided outside the vehicle separately from the vehicle. Further, the charger can convert the voltage value in consideration of the voltage of the external power supply and the voltage of the assembled battery 10. The controller 40 can reduce the current value (charging current) of the assembled battery 10 by controlling the operation of the charger.

  When supplying the electric power of the assembled battery 10 to an external device, a power feeding device can be used. The power feeding device can convert DC power from the assembled battery 10 into AC power and supply the AC power to an external device. Further, the power supply device can convert the voltage value in consideration of the voltage of the assembled battery 10 and the operating voltage of the external device. The controller 40 can reduce the current value (discharge current) of the assembled battery 10 by controlling the operation of the power supply apparatus.

  By limiting the value of the current flowing through the assembled battery 10 according to the number of cut-offs m, it is possible to suppress an increase in the current load on the unit cell 12. Moreover, the electric current value which flows into the electric current breaker 12b which is not act | operating can also be restrict | limited, and it can suppress that the electric current breaker 12b becomes easy to operate | move.

  In this embodiment, the temperature of the single cells 12 of the battery block 11 is monitored, and the temperature is changed with reference to the temperature change amount of the single cells 12 according to the current flowing through the battery block 11 in which all the current breakers 12b are not operated. When the temperature change amount of the unit cell 12 according to the current flowing through the battery block 11 based on the detected temperature detected by the sensor 21 is different, the operating state of the current breaker 12b can be detected.

  Furthermore, with the detection of the operating state of the current breaker 12b, the number of actuations x of the current breaker 12b can be calculated from the rate of increase of the temperature change amount of the unit cell 12 with respect to the reference temperature change amount.

  For this reason, since charging / discharging of the assembled battery 10 can be controlled according to the number m of interruption | blocking, charging / discharging control of the assembled battery 10 can be performed efficiently. Only detecting the operating state of the current breaker 12b may limit the charging / discharging of the battery pack 10 excessively. In this embodiment, the number of breaks m is set based on the amount of change in temperature of the unit cell 12. The charge / discharge of the assembled battery 10 can be appropriately limited according to the number of interruptions m.

  Further, since the operating state of the current breaker 12b is detected by using the temperature change amount of the single battery 12 with respect to the environmental temperature Ta, the internal resistance R of the single battery 12 depending on the environmental temperature Ta (the internal resistance of the battery block 11). ) Can be suppressed, and the operation of the current breaker 12b can be accurately detected.

(Example 2)
A battery system that is Embodiment 2 of the present invention will be described. In the first embodiment, the temperature change amount of the unit cell 12 based on the detected temperature is compared with the temperature change amount of the unit cell 12 based on the current-temperature rise map created in advance, and the presence or absence of the current breaker is detected. However, in the present embodiment, the current breaker operation is performed by comparing the temperature change amount based on the detected temperature of each unit cell 12 between the battery blocks 11 connected in series constituting the assembled battery 10 in series. Detect the presence or absence. In the following description, differences from the first embodiment will be mainly described, and detailed description of the same configuration and processing will be omitted.

  FIG. 8 is a flowchart of the current breaker operation detection process of the present embodiment. The processing shown in FIG. 8 is based on the detected temperatures T1 and T2 between the two arbitrary battery blocks 11 and the environmental temperature Ta, and the temperature change value ΔT1 of the single battery 12 of one battery block 11 and the other battery block 11 A temperature change value ΔT2 of the unit cell 12 is calculated. And the temperature change amount (DELTA) T1, (DELTA) T2 of the cell 12 is compared between different battery blocks, and the presence or absence of the action | operation of the current circuit breaker 12b provided in the cell 12 in the battery block 11 is detected.

  In step S501, the controller 40 selects any two battery blocks 11 from among the plurality of battery blocks 11 constituting the assembled battery 10, and each of the selected two first battery blocks 11 and second battery blocks 11 is selected. Battery temperature T1, T2 and environmental temperature Ta are acquired. Information about the acquired battery temperatures T1 and T2 and the environmental temperature Ta is stored in the memory 41.

  In step S502, the controller 40 calculates the temperature change amount ΔT1 of the unit cell 12 of the first battery block 11. ΔT1 can be obtained by subtracting the environmental temperature Ta from the detected temperature T1 (ΔT1 = T1-Ta). Similarly, the controller 40 calculates the temperature change amount ΔT2 of the single battery 12 of the second battery block 11 (ΔT2 = T2-Ta). These ΔT1 and ΔT2 are the temperature change amounts of the single cells 12 of the different battery blocks 11 at the same detection timing (same detection time).

  In step S503, the controller 40 compares the calculated temperature change amount ΔT1 of the single battery 12 of the first battery block 11 with ΔT2 of the single battery 12 of the second battery block 11. If ΔT1 = ΔT2, the controller 40 performs step S506. Proceed to, and detect that the current breaker 12b of the unit cell 12 included in each of the two battery blocks 11 is not operating.

As described in the first embodiment, the temperature change amount of the single cell 12 of the battery block 11 in the state where the current breaker 12b is activated is the temperature change of the single cell 12 of the battery block 11 where the current breaker 12b is not activated. (N / (N−x) ) ² times the amount. For this reason, when the temperature change amount between the single cells 12 constituting the assembled battery 10 detected at the same time is different, the current breaker 12b of the single cell 12 included in the one battery block 11 is operating. Can be determined. At this time, the temperature change amount of the single cell 12 of the battery block 11 in the state where the current breaker 12b is activated has a rate of increase of (N / (N−x) ) ^2, so the current breaker of the single cell 12 The battery block 11 in which 12b is operating can be specified.

  If it is determined that ΔT1 = ΔT2 is not satisfied in step S503, for example, if it is determined that ΔT2> ΔT1, the controller 40 proceeds to step S504, and the battery block 11 including the unit cell 12 having the higher temperature change amount is changed. It can be specified as the battery block 11 in a state where the current breaker 12b is activated.

  The controller 40 further specifies the number of operations of the current breaker 12b in the battery block 11 with respect to the detection result indicating that the current breaker 12b is activated in step S504. In step S505, the controller 40 calculates the number of actuations x of the current breaker 12b using ΔT1 and ΔT2, and identifies the number of breaks m (= x) of the unit cells 12 whose current path is cut off.

For example, when it is detected that the second battery block 11 is in a state in which the current breaker 12b is activated, the second battery block 11 in the state in which the current breaker 12b is activated as shown in Equation 5 of the first embodiment. The temperature change amount ΔT2 of the unit cell 12 is (N / (N−x) ) ² times the temperature change amount ΔT1 of the unit cell 12 of the first battery block 11 in which the current breaker 12b is not operated. When Expression 6 in Example 1 is expressed using ΔT1 and ΔT2, Expression 8 below is obtained.
(Formula 8)

  At this time, the controller 40 uses the temperature change amount ΔT1 of the unit cell 12 of the first battery block 11 with the lower temperature change amount in step S504, and calculates the temperature increase value based on the current breaker operation detection of the first embodiment. After specifying that the lower first battery block 11 is a battery block in which the current breaker 12b of the unit cell 12 is not activated, the second battery in a state in which the current breaker 12b is activated based on Equation 8 The number of actuations x of the current breaker 12b in the block 11 can be calculated.

  Further, when it cannot be confirmed that the current breaker 12b of the single battery 12 of the first battery block 11 having the lower temperature change amount is not operating (or the temperature change amount of the single battery 12 of the first battery block 11 is The current circuit breaker 12b is activated using the reference temperature change amount based on the current-temperature increase map prepared in advance, when there is a difference between the reference temperature change amount based on the current-temperature increase map prepared in advance. The operation number x of the current breaker 12b in the second battery block 11 in the state may be calculated.

  That is, in this embodiment, the operating state of the current breaker 12b is detected based on the temperature change amount of each unit cell 12 between different battery blocks 11 constituting the assembled battery 10, but the operation of the current breaker 12b is detected. The calculation of the number of activations of the current breaker 12b for the battery block 11 that has been performed is based on the temperature change amount of the unit cell 12 of the battery block 11 with the lower temperature change amount (corresponding to the reference temperature change amount of the first embodiment) This can be performed using the reference temperature change amount based on the created current-temperature rise map.

  In the present embodiment, since the operation of the current breaker 12b is detected based on the temperature change amount of each unit cell 12 between different battery blocks 11 constituting the assembled battery 10 detected at the same time, each battery block is It is possible to suppress the influence of the fluctuation of the flowing current value and the fluctuation of the environmental temperature, and it is possible to detect the operation of the current breaker 12b with higher accuracy.

  In the example of FIG. 7, whether or not the current breaker 12 b is operated is detected by comparing the temperature change amount of each unit cell 12 between any two battery blocks 11. For example, the assembled battery 10 is configured. Among the plurality of battery blocks 11 connected in series, the battery block in which the current breaker 12b is not activated is detected in advance by the current breaker activation detection of the first embodiment, and the identified current breaker 12b is activated. It is configured to detect the operation state and the number of operations of the current breaker 12b by calculating and comparing the temperature change amount of the single battery 12 of the non-battery block and the temperature change amount of any other battery block. May be.

  Further, the operating state of the current breaker 12b may be detected by comparing the temperature change amount of each of the two or more battery blocks 11 and the unit cell 12 with respect to one battery block. For example, after comparing the temperature change amount of each single battery 12 between the first battery block 11 and the second battery block 11, each of the single batteries 12 is further changed between the first battery block 11 and the third battery block 11. You may comprise so that the operating state of the current circuit breaker 12b with respect to the 1st battery block 11 may be detected by comparing a temperature change amount.

  Also in this embodiment, similarly to the modification shown in FIG. 6, the controller 40 detects the temperature change amount ΔT1 of the unit cell 12 of the first battery block 11 and the second battery block 11 acquired through steps S501 and S502. It is possible to detect the operation of the current breaker 12b by using the calculation process (Equation 8) of the number of actuations x based on the rate of increase due to the activation of the current breaker 12b using the temperature change amount ΔT2 of the single cell 12 of it can.

  The controller 40 uses the temperature change amount ΔT1 of the unit cell 12 of the first battery block 11 and the temperature change amount ΔT2 of the unit cell 12 of the second battery block 11 obtained through steps S501 and S502, to obtain a temperature change amount ΔT1 ( The rate of increase of the temperature change amount ΔT2 with respect to the temperature change amount of the unit cell 12 of the battery block in which no current breaker 12b is operating is calculated, and the number of operations x based on the rate of increase due to the operation of the current breaker 12b Is calculated (Equation 8), and it is determined whether or not the calculated operation number x is 1 or more (whether or not the operation number x is an increase rate that satisfies 1 or more), and is included in the battery block 11. It is detected that the current breaker 12b of the unit cell 12 is in operation, and the calculated number of operations x is defined as the number m (= x) of unit cells 12 whose current path is blocked. It can be constant.

(Example 3)
A battery system that is Embodiment 3 of the present invention will be described. In this embodiment, the temperature change of the single cells 12 of one battery block 11 is monitored in time series, and the current interruption is based on the past temperature change history of the single cells 12 in the same battery block 11 grasped in time series. Detects the presence or absence of device operation. In the following description, differences from the first and second embodiments will be mainly described, and a detailed description of the same configuration and processing will be omitted.

  FIG. 9 is a flowchart of the current breaker operation detection process of the present embodiment. The process shown in FIG. 9 is performed for each of a plurality of battery blocks 11 connected in series constituting the assembled battery 10, and the temperature change of the unit cells 12 in one battery block 11 is monitored at each predetermined timing. When the temperature change amounts ΔT1, ΔT2 of the unit cells 12 acquired at the respective timings (time t1, t2) are different, the presence or absence of the current breaker operation is detected. The time t2 is a time after a certain time (Δt) has elapsed from the time t1, and each battery block 11 can perform a current breaker operation detection process by monitoring the temperature change of the unit cell 12 every certain time. it can.

  In step S701, the controller 40 acquires the detected temperature T1, the environmental temperature Ta1, and the current value I1 of the battery block 11 at the time t1 when the current circuit breaker operation detection process starts or after the start. In step S702, the controller 40 calculates the temperature change amount ΔT1 of the unit cell 12. ΔT1 can be obtained by subtracting the environmental temperature Ta1 from the detected temperature T1 (ΔT1 = T1−Ta1).

  The controller 40 stores the acquired information about the detected temperature T1, the environmental temperature Ta1, the current value I1, and the calculated temperature change ΔT1 in the memory 41 as the temperature rise history of the battery block 11 at time t1.

  Subsequently, in step S703, the controller 40 obtains the detected temperature T2, the environmental temperature Ta2, and the current value I2 of the same battery block 11 at time t2 after a predetermined time has elapsed from time t1. In step S704, the controller 40 calculates the temperature change amount ΔT2 of the unit cells 12 of the same battery block 11 at time t2. Similarly, ΔT2 can be obtained by subtracting the environmental temperature Ta2 from the detected temperature T2 at time t2 (ΔT2 = T2−Ta2).

  The controller 40 stores the acquired information about the detected temperature T2, the environmental temperature Ta2, the current value I2, and the calculated temperature change ΔT2 in the memory 41 as the temperature rise history of the battery block 11 at time t2.

Here, as described above, the internal resistance R of the unit cell 12 varies depending on the ambient temperature of the battery block 11, that is, the environmental temperature Ta. Therefore, the temperature change amount calculated at each of the times t 1 and t 2 (temperature increase value). ) ΔT1 and ΔT2 and the internal resistances R1 and R2 of the unit cell 12 at that time are as follows from the relationship of the above equation 2.
(Formula 9) R1 = (N / I1) ² × (ΔT1 / θ)
(Formula 10) R2 = (N / I2) ² × (ΔT2 / θ)
The internal resistance R1 is an internal resistance at the environmental temperature Ta1 at time t1, and the current value I1 is a current value that has flowed through the battery block 11 at time t1. Similarly, the internal resistance R2 is the internal resistance at the environmental temperature Ta2 at time t2, and the current value I2 is the current value that flows through the battery block 11 at time t2.

  Therefore, if the current breaker 12b is not activated, assuming that the increase in internal resistance due to battery deterioration due to aging with respect to the times t1 and t2 is extremely small, if the environmental temperature Ta1 and the environmental temperature Ta2 are the same, the time t1 , T2 and the internal resistances R1 and R2 of the unit cell 12 calculated from the temperature changes ΔT1 and ΔT2 should be the same. That is, when the internal resistances R1 and R2 of the unit cell 12 calculated from the temperature change amounts ΔT1 and ΔT2 are not the same, there is a difference between the temperature change amounts ΔT1 and ΔT2.

  Therefore, in this embodiment, from the temperature change amount ΔT1 (corresponding to the past temperature change amount) and ΔT2 (corresponding to the current temperature change amount) of the unit cell 12 at each time t1, t2 of the same battery block 11. The change in the internal resistances R1 and R2 at each time t1 and t2 is captured, the difference between the temperature change amounts ΔT1 and ΔT2 is identified, and the presence or absence of the current breaker operation is detected.

  In other words, when the temperature change values ΔT1 and ΔT2 of the single cells 12 at the times t1 and t2 are simply compared, the presence or absence of the current breaker operation is accurately detected due to the influence of the environmental temperatures Ta1 and Ta2 that are different at the times t1 and t2. Therefore, the temperature change amounts ΔT1 and ΔT2 of the single cells 12 of the battery block 11 are monitored in time series, and the difference between the temperature change amounts ΔT1 and ΔT2 is changed in the internal resistances R1 and R2 at the times t1 and t2. The current breaker is activated or not.

  Here, when comparing the internal resistances R1 and R2 at the times t1 and t2, the environmental temperatures at the respective times are different. Therefore, after normalizing (normalizing) the internal resistances R1 and R2 with a predetermined reference environmental temperature Tref, By comparing the standardized internal resistances R1 ′ and R2 ′, a difference between the temperature change amounts ΔT1 and ΔT2 is detected.

For example, the standardized internal resistances R1 ′ and R2 ′ with respect to the reference environment temperature Tref can be calculated using the reference internal resistance Rref at a predetermined reference environment temperature Tref.

Specifically, when the reference internal resistance Rref at the reference environmental temperature Tref (for example, 25 ° C.) is used, the internal resistance R (t) at time t has the following relationship.
(Expression 12) R (t) = Rref + a (T (t) −Tref)
Here, T (t) is the environmental temperature at time t. T (t) −Tref is a temperature change amount with respect to the reference environment temperature Tref. a is a correction coefficient. The correction coefficient a can be calculated in advance from, for example, the correspondence relationship between the reference environment temperature Tref and the reference internal resistance Rref (for example, the rate of increase in internal resistance per unit temperature).

  When R2 ′ normalized by the reference environment temperature Tref based on Expression 12 is larger than R1 ′, the temperature change amounts ΔT1 and ΔT2 are different. For example, when the temperature change amount ΔT2 is normalized by the environment temperature Ta1, ΔT2 has a higher temperature rise value than ΔT1 based on the heat generation amount.

On the other hand, among the N unit cells 12 of the same battery block 11, the number of the unit cells 12 in which the current breaker 12b is activated at time t1 is zero, and the number of the unit cells 12 in which the current breaker 12b is activated at time t2 is x. In the case of the number of pieces, the temperature change amount of the battery block 11 at time t1 is
(Formula 13) ΔT1 = Q1 × θ = (I1 / N) ² × R1 × θ
The amount of change in temperature of the battery block 11 at time t2 is
(Expression 14) ΔT2 = Q2 × θ = (I2 / (N−x)) ² × R2 × θ
It becomes.

If Formula 14 is further modified, Formula 15 can be derived.
(Formula 15) ΔT2 = (I2 / (N−x)) ² × R2 × θ
= (N / (N−x)) ² × (I2 / I1) ² × (R2 / R1) × ΔT1
The temperature change ΔT2 of the unit cell 12 of the battery block 11 in the state where the current breaker 12b is activated at time t2 is equal to the temperature change ΔT1 of the battery block 11 where the current breaker 12b is not activated at time t1 (N / (N−x)) ² × (I2 / I1) ² × (R2 / R1) times.

And when the above equation 15 is transformed,
(Expression 16) ΔT2 / ΔT1 = (N / (N−x)) ² × (I2 / I1) ² × (R2 / R1)
Then, when Equation 16 is expanded with the operation number x,
(Formula 17)
It becomes. According to Expression 16 and Expression 17, in the battery block 11 in the state where the current breaker 12b at time t2 is activated with respect to the temperature change ΔT1 of the single cell 12 in the battery block 11 where the current breaker 12b is not activated at time t1. The rate of increase of the temperature change amount T2 of the unit cell 12 includes current values I1, I2 detected at times t1, t2 and internal resistances R1, R2 calculated from the temperature change amounts ΔT1, ΔT2 as parameters. When this parameter is A, Expression 16 and Expression 17 can be expressed as Expression 18 and Expression 19 below.
(Expression 18) ΔT2 / ΔT1 = (N / (N−x)) ² × A
(Formula 19)
However,
The parameter A is the amount of heat generated with respect to the rate of change of the internal resistance and the detected current that fluctuate according to each environmental temperature at time t2 with respect to time t1. By accurately correcting the change rate of the internal resistance and the detected current at time t2 with respect to time t1, the number of operations of the current breaker 12b with respect to the temperature change amount of the unit cell 12 of the battery block 11 at time t2 can be accurately specified. Can do.

  Returning to the description of FIG. 9, in step S705, the controller 40 uses the temperature changes ΔT1 and ΔT2 of the unit cell 12 at the times t1 and t2, and the current values I1 and I2 detected by the current sensor 31, respectively. From Equations 9 and 10, internal resistance R1 is calculated for battery block 11 at time t1, and internal resistance R2 is calculated for battery block 11 at time t2. At this time, as described above, R1 ′ and R2 ′ are calculated by further normalizing with the reference environment temperature Tref based on Expression 12.

  In step S706, the controller 40 compares the standardized internal resistance R1 ′ at time t1 with the standardized internal resistance R2 ′ at time t2, and if R1 ′ = R2 ′, the process proceeds to step S707. It is detected that the current breaker 12b of the unit cell 12 included in the battery block 11 to be processed is not activated.

  On the other hand, if it is determined in step S706 that R1 ′ = R2 ′ is not satisfied, that is, if it is determined that R2 ′> R1 ′, the controller 40 proceeds to step S707, and the battery block 11 is connected to the current breaker 12b. Is detected as a battery block 11 including a single battery 12 in which is operated.

  The controller 40 further specifies the number of operations of the current breaker 12b in the battery block 11 with respect to the detection result indicating that the current breaker 12b is activated in step S707. In step S708, the controller 40 calculates the temperature changes ΔT1, ΔT2, the current values I1, I2 of the unit cell 12 at times t1, t2, and the internal resistances R1, R2 at times t1, t2 calculated in step S705. Using this, the number of operations x of the current breaker 12b is calculated (Equation 17), and the number of breaks m (= x) of the unit cells 12 whose current path is cut off is specified.

  The controller 40 uses the temperature change amount ΔT1 at time t1 in step S703, and the battery block 11 at time t1 is activated and the current breaker 12b of the unit cell 12 is activated based on the current breaker activation detection of the first embodiment. After identifying (confirming) that the battery block is not, the operation of the current breaker 12b is detected by comparing the temperature change value ΔT2 at time t2 with the temperature change value ΔT1 at the past time t1, and the equation 17 The operation number x of the current breaker 12b in the battery block 11 in the state where the current breaker 12b is activated at time t2 based on the above can be calculated.

  In addition, when it cannot be confirmed that the battery block 11 at time t1 is a battery block in which the current breaker 12b of the unit cell 12 is not activated, the reference temperature change at time t1 based on a current-temperature rise map created in advance. The amount x may be used to calculate the number of actuations x of the current breaker 12b in the battery block 11 in a state where the current breaker 12b is activated at time t2 based on Equation 17.

  That is, also in the present embodiment, the temperature change of the single cells 12 of the same battery block 11 constituting the assembled battery 10 is monitored in time series, and based on the past temperature change history of the single cells 12 grasped in time series. Whether or not the current breaker is activated is detected, but the number of activations of the current breaker 12b for the battery block 11 in which the activation of the current breaker 12b is detected is calculated based on the temperature change amount of the unit cell 12 at time t1 or in advance. This can be done using the reference temperature change amount at time t1 based on the current-rise change map.

  In this embodiment, temperature changes at different times of the single cells 12 of the same battery block 11 are monitored, and whether or not the current breaker is activated is detected based on the past temperature change history of the single cells 12 grasped in time series. Therefore, it is possible to suppress the influence of the variation of the internal resistance due to the variation at the time of manufacture of the unit cell 12 constituting the battery block 11, and the secular change (several months, years) of the increase in the internal resistance due to the battery deterioration. ) Of the monitoring cycle is extremely small (for example, several minutes to several days), so that the influence of the increase in internal resistance due to battery deterioration can be suppressed, and the operation of the current breaker 12b can be performed more accurately. The presence or absence can be detected.

  Also in this embodiment, similarly to the modification shown in FIG. 6, the controller 40 calculates the current value from the temperature change amounts ΔT1 and ΔT2 of the unit cell 12 at the times t1 and t2 acquired through steps S701 to S704. The current breaker 12b is calculated by calculating the number of operations x based on the rate of increase in temperature (Equation 17 or Equation 19) when the current breaker 12b is activated using I1, I2 and the internal resistances R1, R2 as parameters (parameter A). Can be detected.

  The controller 40 sets the temperature change amount ΔT2 of the single cell 12 at time t2 with respect to the temperature change amount ΔT1 of the single cell 12 at time t1 (temperature change amount of the single cell 12 at time t1 when the current breaker 12b is not operating). Whether the calculated operation number x is 1 or more by calculating the rate of increase and calculating the operation number x based on the temperature listing rate due to the operation of the current breaker 12b (the operation number x is 1 or more) Whether the current breaker 12b of the unit cell 12 included in the battery block 11 at time t2 is in operation, and the calculated number of operations. x can be specified as the number of interruptions m (= x) of the unit cells 12 whose current path is interrupted.

  In the first to third embodiments, the current breaker operation detection process is performed for each of the plurality of battery blocks 11 constituting the assembled battery 10. At this time, when the operation of the current breaker 12b is detected in at least two or more battery blocks 11, in the charge / discharge control process after the current breaker operation detection process shown in FIG. Charge / discharge control is performed so that the maximum number of interruptions m (operation number x) is specified from each battery block 11 in which the operation of the battery 12b is detected, and the current command value is set based on the specified maximum interruption number. It can be carried out.

10: assembled battery 11: battery block 12: single battery 12b: current breaker 20: monitoring unit 21: temperature sensor 31: current sensor 32: booster circuit 33: inverter 34: motor generator 40: controller 41: memory

Claims (8)

Each having a plurality of power storage elements connected in parallel, a plurality of power storage blocks connected in series,
A temperature sensor for detecting the temperature of the power storage block and the ambient temperature of the power storage element;
A controller that determines a state of each power storage block using a temperature change amount of the power storage element according to a temperature difference between the ambient temperature and a detected temperature of the power storage block;
Each of the electricity storage elements has a current breaker that interrupts a current path inside the electricity storage element,
The controller is connected in parallel to the power storage element in which the current breaker is in a cut-off state with respect to a current value flowing through the power storage element of the power storage block in which each current breaker of all the power storage elements is not in a cut-off state. based on the relationship value of the current flowing through the rest of the storage element is increased in accordance with the cut-off number of the circuit breakers, the first temperature change amount of the electric storage device in accordance with the current flowing in the power storage block, connected in parallel Different from the second temperature change amount of the electricity storage element according to the current flowing through the electricity storage block in which each current breaker of all the electricity storage elements is not in the interruption state, the first temperature change amount is the number of interruptions of 1 power storage sheet, characterized by detecting a case of have a rate of increase in temperature variation, the circuit breaker of the power storage device included in the power storage block is cutoff state to the second temperature change amount equal to or larger than Temu. The controller is
From the current-temperature change map that predetermines the temperature change amount of the electricity storage element according to the current value flowing through the electricity storage block in which each current breaker of all electricity storage elements connected in parallel is not in the cut-off state, by the current sensor A temperature change amount corresponding to the detected current flowing through the power storage block to be detected is calculated as the second temperature change amount;
2. The power storage system according to claim 1 , wherein the first temperature change amount is compared with the second temperature change amount based on the current-temperature change map. The controller is
Obtaining a temperature change amount of the electricity storage element according to a current flowing in a second electricity storage block different from the first electricity storage block corresponding to the first temperature change amount as the second temperature change amount;
The power storage system according to claim 1 , wherein a temperature change amount of each power storage element between the different power storage blocks is compared. The controller is
Acquired in chronological temperature variation of the electric storage device in accordance with the current flowing in the power storage block,
Comparing the current temperature change amount and the past temperature change amount of the power storage elements of the same power storage block, where the current temperature change amount is the first temperature change amount and the past temperature change amount is the second temperature change amount. The power storage system according to claim 1 . The controller is
Using the first detected current of the current sensor at the first time corresponding to the past temperature change amount and the past temperature change amount, the first internal resistance of the power storage element at the first time is calculated, and Using the second detected current of the current sensor at a second time after a certain time has elapsed from the first time corresponding to the current temperature change amount and the current temperature change amount, Calculate the second internal resistance,
When the first internal resistance and the second internal resistance differ from each temperature change amount of the power storage element at the first time and the second time, the current breaker of the power storage element included in the power storage block is cut off The power storage system according to claim 4 , wherein the power storage system is detected as being in a state. The controller uses the rate of increase of the first temperature change amount with respect to the second temperature change amount between the first temperature change amount and the second temperature change amount, and the current included in the power storage block. power storage system according to claim 1, any one of 5 breaker and identifies the number of storage elements in the blocking state. The current breaker is a fuse that cuts off the current path by fusing, a PTC element that cuts off the current path due to an increase in resistance due to a temperature rise, or a deformation in response to an increase in internal pressure of the power storage element, power storage system according to any one of claims 1 to 6, characterized in that the current cutoff valve for cutting off the current path. A method for determining the state of the power storage block of a power storage system configured by connecting a plurality of power storage blocks connected in parallel with a plurality of power storage elements having a current breaker that cuts off a current path,
The temperature of the power storage block and the ambient temperature of the power storage element are detected by a temperature sensor, and the temperature change amount of the power storage element according to the temperature difference between the ambient temperature and the detected temperature of the power storage block is calculated.
The remaining power storages connected in parallel to the power storage elements in which the current breaker is in a cut-off state with respect to the current value flowing through the power storage elements in the power storage block in which the current breakers of all the power storage elements are not in the cut-off state Based on the relationship in which the current value flowing through the element increases according to the number of interruptions of the current breaker , the first temperature change amount of the electricity storage element according to the current flowing through the electricity storage block is all connected in parallel. Unlike the second temperature change amount of the electricity storage element according to the current flowing through the electricity storage block in which each current breaker of the electricity storage element is not in an interrupted state, the first temperature change amount is such that the number of interruptions is 1 or more. discriminating method characterized by detecting a case of have a rate of increase in temperature variation with respect to the second temperature change amount, the current breaker of the power storage device included in the power storage block is turned off.