JP2014143138A - Battery system and method for controlling input to nonaqueous secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly protect a nonaqueous secondary battery by considering battery degradation caused by moisture permeation into the battery.SOLUTION: A battery system has a controller for controlling input to a nonaqueous secondary battery by lowering, according to a degradation state of the nonaqueous secondary battery, a permissible input current value which is a maximum current value tolerated for input to the nonaqueous secondary battery. The controller changes, according to a first degradation degree based on a history of charge/discharge of the nonaqueous secondary battery and a second degradation degree based on a history of moisture permeation into the nonaqueous secondary battery, a reduction rate at which the permissible input current value is lowered. Because the reduction rate of the permissible input current value corresponding to battery degradation is changed by considering moisture permeation into the nonaqueous secondary battery, it is possible to properly protect the nonaqueous secondary battery by suppressing its overdischarge.

Description

  The present invention relates to a technique for controlling charging of a non-aqueous secondary battery such as a lithium ion secondary battery.

  In patent document 1, when charging a lithium ion secondary battery, in order to suppress precipitation of lithium metal, the allowable input current value is set. Here, the allowable input current value is corrected in accordance with the degree of deterioration of the battery in consideration of the aging deterioration of the secondary battery.

International Publication No. 2010/005079 Pamphlet

  The nonaqueous secondary battery in which the electrolyte is composed of a nonaqueous electrolyte is known to deteriorate battery characteristics due to the permeation of moisture (water vapor) into the battery, but in the technique described in Patent Document 1, Although the deterioration degree of the charge / discharge history based on the battery capacity, the internal resistance of the battery, and the electromotive voltage of the battery is estimated (calculated), the deterioration degree due to moisture permeation into the battery is not taken into consideration.

  Therefore, an object of the present invention is to appropriately protect a non-aqueous secondary battery in consideration of battery degradation caused by moisture permeation into the battery.

  The battery system according to the first aspect of the present invention reduces the allowable input current value, which is the maximum current value allowing the input of the non-aqueous secondary battery, in accordance with the deterioration state of the non-aqueous secondary battery. A controller for controlling the input of the secondary battery; When the controller decreases the allowable input current value according to the first deterioration degree based on the charge / discharge history of the non-aqueous secondary battery and the second deterioration degree based on the moisture permeation history into the non-aqueous secondary battery. Change the rate of decline.

  According to the first invention of the present application, since the rate of decrease in the allowable input current value corresponding to the battery deterioration is changed in consideration of moisture permeation into the non-aqueous secondary battery, overcharge is suppressed, The secondary battery can be appropriately protected.

  Here, the moisture permeation history depends on the battery temperature of the non-aqueous secondary battery and the ambient humidity, and the battery system includes a temperature sensor that detects the battery temperature of the non-aqueous secondary battery, and a non-aqueous secondary battery. And a humidity sensor that detects ambient humidity. The controller calculates the amount of moisture permeation according to the detected humidity based on the moisture permeability into the non-aqueous secondary battery depending on the detected battery temperature at each predetermined timing, and A moisture permeation integrated value obtained by integrating the moisture permeation calculated at the timing can be calculated as a moisture permeation history.

  In addition, the controller can be configured to correct the first deterioration degree according to the second deterioration degree and change the reduction rate based on the corrected first deterioration degree.

  The battery system may further include a current sensor that detects a current value of the non-aqueous secondary battery and a voltage sensor that detects a voltage value of the non-aqueous secondary battery, and the controller detects the detected current. When the first deterioration degree corresponding to the charge / discharge history of the non-aqueous secondary battery based on the value and the voltage value is smaller than the predicted deterioration degree set in advance for the non-aqueous secondary battery, only the first deterioration degree Accordingly, the reduction rate when the allowable input current value is reduced can be changed.

  As the non-aqueous secondary battery, a lithium ion secondary battery can be used. In this case, the controller controls the input of the non-aqueous secondary battery so as to set the allowable input current value so that the negative electrode potential of the lithium ion secondary battery does not become lower than the reference potential that regulates the deposition of lithium metal. .

  The control method according to the second invention of the present application is to reduce the allowable input current value, which is the maximum current value allowing the input of the non-aqueous secondary battery, according to the deterioration state of the non-aqueous secondary battery. A control method for controlling the input of the secondary battery according to a first deterioration degree based on a charge / discharge history of the non-aqueous secondary battery and a second deterioration degree based on moisture permeation history into the non-aqueous secondary battery. The rate of decrease when the allowable input current value is decreased is changed. According to the second invention of the present application, the same effects as those of the first invention of the present application are exhibited.

It is a figure which shows the structure of the battery system in Example 1. FIG. It is a figure in Example 1 which shows the change of the positive electrode potential according to charge capacity, and a negative electrode potential. It is a figure which shows the relationship between the degradation parameter D and degradation coefficient (eta) in Example 1. FIG. FIG. 3 is a diagram showing a relationship between the internal resistance of a single cell and a deterioration parameter D in Example 1. 3 is a diagram illustrating an example of an internal structure of a unit cell in Example 1. FIG. It is a figure in Example 1 which shows the relationship between the water permeation performance to the inside of a single cell, and temperature. It is a figure in Example 1 which shows the relationship between the moisture permeation amount inside a single cell, and humidity. It is a figure which shows the relationship between the moisture permeation amount into the inside of a single cell, and the degradation parameter D 'in Example 1. In Example 1, it is a figure which shows the relationship of the correction | amendment degradation parameter Dh which the water permeation amount considered with respect to the degradation parameter D based on the internal resistance of a cell. FIG. 3 is a diagram illustrating a processing flow for calculating a moisture permeation amount into a single cell in Example 1; 6 is a flowchart illustrating a process of setting an allowable input current value in the process of controlling charging / discharging of the assembled battery in Example 1. 10 is a flowchart illustrating a modification of the process for setting the allowable input current value in the first embodiment. It is a figure which shows the relationship of the internal resistance estimated value according to the usage time of an assembled battery in the modification of FIG.

  Examples of the present invention will be described below.

  A battery system that is Embodiment 1 of the present invention will be described. FIG. 1 is a diagram showing the configuration of the battery system of this example. The battery system of the present embodiment can be 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, which will be described later, as a power source for running the vehicle.

  The assembled battery 10 includes a plurality of unit cells 11 connected in series. As the unit cell 11, a nonaqueous electrolyte secondary battery such as a lithium ion secondary battery can be used. The number of unit cells 11 constituting the assembled battery 10 can be appropriately set in consideration of the required output of the assembled battery 10 and the like. In the present embodiment, all the unit cells 11 are connected in series to form the assembled battery 10, but the assembled battery 10 may include a plurality of unit cells 11 connected in parallel.

  For example, the positive electrode of the unit cell 11 is formed of a material that can occlude and release ions (for example, lithium ions). As a positive electrode material, for example, lithium cobaltate or lithium manganate can be used. The negative electrode of the unit cell 11 is formed of a material that can occlude and release ions (for example, lithium ions). As the negative electrode material, for example, carbon can be used. When charging the unit cell 11, the positive electrode releases ions into the electrolytic solution, and the negative electrode occludes ions in the electrolytic solution. Further, when discharging the unit cell 11, the positive electrode occludes ions in the electrolytic solution, and the negative electrode releases ions into the electrolytic solution.

  The monitoring unit 21 detects the inter-terminal voltage VB of the assembled battery 10 or detects the inter-terminal voltage VB of the unit cell 11 and outputs the detection result to the controller 30. When the plurality of single cells 11 constituting the assembled battery 10 are divided into a plurality of battery blocks, the monitoring unit 21 can also detect the voltage between the terminals of each battery block. For example, each battery block can be configured by a plurality of single cells 11 connected in series or in parallel, and the assembled battery 10 is configured by connecting the plurality of battery blocks in series.

  The current sensor 22 detects the current value IB flowing through the assembled battery 10 and outputs the detection result to the controller 30. In the present embodiment, a negative value (IB <0) is used as the current value IB detected by the current sensor 22 when charging the assembled battery 10. Further, a positive value (IB> 0) is used as the current value IB detected by the current sensor 22 when the battery pack 10 is discharged.

  In the present embodiment, the current sensor 22 is provided in the positive electrode line PL connected to the positive electrode terminal of the assembled battery 10, but the present invention is not limited to this. That is, the current sensor 22 only needs to detect the current value IB flowing through the battery pack 10. For example, the current sensor 22 can be provided on the negative electrode line NL connected to the negative electrode terminal of the assembled battery 10. A plurality of current sensors 22 can also be used.

  The temperature sensor 23 detects the temperature TB of the assembled battery 10 (unit cell 11) and outputs the detection result to the controller 30. The number of temperature sensors 23 can be set as appropriate. When a plurality of temperature sensors 23 are used, the temperature sensors 23 can be arranged at different positions with respect to the assembled battery 10. When the detection results from the plurality of temperature sensors 23 vary, any one of the detection results can be used as the battery temperature TB, or an average value of the plurality of detection results can be used as the battery temperature TB.

  The humidity sensor 24 detects the humidity WB around the assembled battery 10 (single cell 11) and outputs the detection result to the controller 30. As with the temperature sensor 23, the number of the humidity sensors 24 can be set as appropriate, and a plurality of humidity sensors 24 can be arranged at different positions with respect to the assembled battery 10. When the detection results by the plurality of temperature sensors 24 vary, any one of the detection results can be used as the humidity WB, or an average value of the plurality of detection results can be used as the humidity WB.

  The assembled battery 10 is connected to the inverter 24 via the positive electrode line PL and the negative electrode line NL. A system main relay SMR-B is provided in the positive electrode line PL, and a system main relay SMR-G is provided in the negative electrode line NL. System main relays SMR-B and SMR-G are switched between ON and OFF in response to a control signal from controller 30.

  A system main relay SMR-P and a current limiting resistor R are connected in parallel to the system main relay SMR-G. Here, the system main relay SMR-P and the current limiting resistor R are connected in series. System main relay SMR-P is switched between on and off in response to a control signal from controller 30.

  The current limiting resistor R is used to suppress the inrush current from flowing through the capacitor C. Capacitor C is connected to positive electrode line PL and negative electrode line NL, and is used to smooth voltage fluctuations between positive electrode line PL and negative electrode line NL.

  When connecting the assembled battery 10 to the inverter 24, the controller 30 first switches the system main relays SMR-B and SMR-P from off to on. Thereby, a current can be passed through the current limiting resistor R. Next, the controller 30 switches the system main relay SMR-G from off to on and switches the system main relay SMR-P from on to off.

  Thereby, the connection between the assembled battery 10 and the inverter 24 is completed, and the battery system shown in FIG. 1 is in a start-up state (Ready-On). Information about on / off of the ignition switch of the vehicle is input to the controller 30, and when the ignition switch is switched from off to on, the controller 30 activates the battery system shown in FIG. On the other hand, when the ignition switch is switched from on to off, the controller 30 switches the system main relays SMR-B and SMR-G from on to off. Thereby, the connection between the assembled battery 10 and the inverter 24 is cut off, and the battery system shown in FIG. 1 enters a stopped state (Ready-Off).

  The inverter 24 converts the DC power output from the assembled battery 10 into AC power, and outputs the AC power to the motor generator (MG) 25. For example, a three-phase AC motor can be used as the motor / generator 25. The motor / generator 25 receives AC power from the inverter 24 and generates kinetic energy for running the vehicle. The motor / generator 25 is connected to wheels, and the kinetic energy generated by the motor / generator 25 is transmitted to the wheels. Thereby, the vehicle can be driven.

  When the vehicle is decelerated or stopped, the motor / generator 25 converts kinetic energy generated during braking of the vehicle into electric energy (AC power). The inverter 24 converts the AC power output from the motor / generator 25 into DC power and outputs the DC power to the assembled battery 10. Thereby, regenerative electric power can be stored in the assembled battery 10.

  The controller 30 includes a memory 31, and the memory 31 stores information for the controller 30 to execute a specific process (particularly, a process described in the present embodiment). In this embodiment, the memory 31 is built in the controller 30, but the memory 31 can be provided outside the controller 30.

  In the battery system of the present embodiment, the assembled battery 10 is connected to the inverter 24, but the present invention is not limited to this. Specifically, a booster circuit can be provided in the current path between the assembled battery 10 and the inverter 24. If the booster circuit is used, the output voltage of the assembled battery 10 can be boosted and the boosted power can be output to the inverter 24. Further, by using the booster circuit, it is possible to step down the output voltage of the inverter 24 and output the stepped down power to the assembled battery 10.

  When the cell 11 is charged, the voltage value VB of the cell 11 increases. As shown in FIG. 2, the voltage value VB of the unit cell 11 is a difference between the positive electrode potential and the negative electrode potential. Therefore, as the unit cell 11 is charged, the positive electrode potential increases and the negative electrode potential decreases. Here, when the negative electrode potential is lower than a reference potential (for example, 0 [V]), lithium metal may be deposited on the surface of the negative electrode.

  When the cell 11 is in an energized state, an overvoltage is generated. The overvoltage is the amount of voltage change associated with the internal resistance of the unit cell 11. If the energization of the unit cell 11 is stopped, the overvoltage decreases. When the unit cell 11 is charged, the voltage value VB (CCV: Closed Circuit Voltage) of the unit cell 11 is increased by the amount of overvoltage with respect to the open circuit voltage (OCV) of the unit cell 11. For this reason, the negative electrode potential may be lower than the reference potential depending on the overvoltage.

  Therefore, in this embodiment, in order to suppress the deposition of lithium metal, an allowable input current value is set, and the input current value (charging current value) of the single battery 11 (the assembled battery 10) does not exceed the allowable input current value. I am doing so. The allowable input current value is the maximum current value allowed when the cell 11 is charged.

  When the allowable input current value increases, the current value when charging the cell 11 can be increased, and the input performance of the cell 11 can be improved. On the other hand, when the allowable input current value decreases, the current value when charging the unit cell 11 cannot be increased, and the charging of the unit cell 11 is likely to be limited.

  The allowable input current value is set as described below, and the setting process of the allowable input current value is performed by the controller 30.

  When there is no charge / discharge history of the assembled battery 10, in other words, when charging / discharging the assembled battery 10 is performed for the first time, the allowable input current value Ilim [t] is calculated based on the following equation (1).

  In the above formula (1), Ilim [0] is the maximum allowable input current value that can suppress deposition of lithium metal within a unit time when charging is performed from a state where there is no charge / discharge history. The allowable input current value Ilim [0] can be obtained in advance by experiments or the like, and information on the allowable input current value Ilim [0] can be stored in the memory 31.

  The second term on the right side of the formula (1) is expressed as a function F of the current value IB, the battery temperature TB, and the SOC (State of Charge). For this reason, the value of the function F is calculated by specifying the current value IB, the battery temperature TB, and the SOC. Here, as current value IB, battery temperature TB, and SOC, values at time t are used, respectively. Moreover, SOC shows the ratio of the present charge capacity with respect to a full charge capacity.

  The SOC of the assembled battery 10 or the single battery 11 can be estimated using a known method. For example, the SOC of the assembled battery 10 (unit cell 11) can be estimated by integrating the current value IB when the assembled battery 10 (unit cell 11) is charged and discharged. On the other hand, since OCV and SOC are in a predetermined correspondence relationship, if this correspondence relationship is obtained in advance, the SOC corresponding to the OCV can be specified by measuring the OCV of the assembled battery 10 (unit cell 11). Can do.

  When charging is continued from a state where there is no charge / discharge history until time t, the value of the second term on the right side of the above equation (1) indicates the amount by which the allowable input current value Ilim is decreased per unit time. Subtracted from the current value Ilim [0]. On the other hand, when the discharge is continued from the state where there is no charge / discharge history until time t, the value of the second term on the right side of the above equation (1) is the amount by which the allowable input current value Ilim is increased (recovered) per unit time. And is added to the allowable input current value Ilim [0].

  The third term on the right side of the above equation (1) is expressed as a function G of time t, battery temperature TB, and SOC. For this reason, the value of the function G is calculated by specifying the time t, the battery temperature TB, and the SOC. Here, values at time t are used as the battery temperature TB and SOC, respectively. The value of the third term on the right side of the above formula (1) indicates the amount by which the allowable input current value Ilim is increased (recovered) per unit time when the assembled battery 10 is left unattended. Here, leaving the assembled battery 10 is a state where charging / discharging of the assembled battery 10 is stopped (non-energized state).

  On the other hand, when there is a charging / discharging history of the assembled battery 10, in other words, after charging / discharging the assembled battery 10, the allowable input current value Ilim [t] is calculated based on the following equation (2).

  In the above equation (2), Ilim [t] is an allowable input current value at time t (current), and Ilim [t−1] is an allowable input current value at time “t−1” (previous). . The second term on the right side of the equation (2) is expressed as a function f of the current value IB, the battery temperature TB, and the SOC.

  The function f depends on the current value IB, the battery temperature TB, and the SOC. That is, the value of the second term on the right side of the formula (2) can be calculated by specifying the current value IB, the battery temperature TB, and the SOC. Here, as current value IB, battery temperature TB, and SOC, values at time t are used, respectively.

  When the assembled battery 10 is charged, the value of the second term on the right side of the above equation (2) indicates the amount (decrease amount) by which the allowable input current value Ilim is decreased per unit time, and the allowable input current value Ilim [t -1]. As described above, since the current value IB at the time of charging is a negative value, the allowable input current value Ilim approaches 0 [A] when the allowable input current value Ilim is decreased.

  On the other hand, when the battery pack 10 is discharged, the value of the second term on the right side of the above formula (2) indicates the amount (recovery amount) by which the allowable input current value Ilim is increased (recovered) per unit time. It is added to the current value Ilim [t−1]. Here, when the allowable input current value Ilim is increased, the allowable input current value Ilim moves away from 0 [A].

  The third term on the right side of the above equation (2) is represented by the function g of the battery temperature TB and the SOC and the allowable input current values Ilim [0], Ilim [t−1]. Further, as shown in the above equation (3), the function g is expressed as a coefficient β, and the coefficient β depends on the battery temperature TB and the SOC. For this reason, the coefficient β corresponding to the battery temperature TB and the SOC can be specified by obtaining in advance a map showing the correspondence relationship between the coefficient β and the battery temperature TB and the SOC. As battery temperature TB and SOC, values at time t are used, respectively.

  Here, a map indicating the correspondence relationship between the coefficient β, the battery temperature TB, and the SOC can be stored in the memory 31. The value of the third term on the right side of the above equation (2) indicates the amount (recovery amount) by which the allowable input current value Ilim is increased (recovered) per unit time when the assembled battery 10 is left unattended. The value of the third term on the right side of the above equation (2) is added to the allowable input current value Ilim [t−1].

  When the allowable input current value Ilim [t] is 0 [A], the lithium ions in the negative electrode active material in the unit cell 11 are saturated. Therefore, the value “Ilim [0] −Ilim [t]” indicates the amount of lithium ions in the negative electrode active material. Here, the amount of recovery described above can be increased in accordance with a decrease in the amount of lithium ions in the negative electrode active material.

  The recovery amount at time t depends on the recovery amount at time “t−1”, and the recovery amount at time “t−1” is represented by “Ilim [0] −Ilim [t−1]”. Here, in the third term on the right side of the above formula (2), in order to make the value of “Ilim [0] −Ilim [t−1]” dimensionless, “Ilim [0] −Ilim [t−1] Is divided by Ilim [0]. By multiplying this divided value by a coefficient β, a recovery amount per unit time can be obtained.

  The above formulas (1) and (2) indicate the allowable input current value Ilim [t] when the deterioration of the unit cell 11 is not considered. Here, since the unit cell 11 is known to deteriorate due to use (charging / discharging), it is preferable to set the allowable input current value Ilim [t] in consideration of the deterioration of the unit cell 11. The allowable input current value Ilim_d [t] in consideration of the deterioration of the unit cell 11 can be calculated based on the following formula (4).

  In the above equation (4), η represents a deterioration coefficient. The allowable input current value Ilim_d [t] taking into account the deterioration of the unit cell 11 can be specified by multiplying the allowable input current value Ilim [t] shown in the above equations (1) and (2) by the deterioration coefficient η. it can. Here, the deterioration coefficient η can be set in advance, and information on the deterioration coefficient η can be stored in the memory 31.

  The deterioration coefficient η is a correction coefficient for correcting the allowable input current value Ilim [t] according to the degree of deterioration of the battery, and can be calculated using, for example, a deterioration parameter D indicating the degree of deterioration of the single battery 11.

  FIG. 3 is a diagram showing the relationship between the degradation coefficient η and the degradation parameter D. In FIG. 3, the number given to the deterioration parameter D indicates the service life of the unit cell 11 (the assembled battery 10). D0 is the degree of deterioration in the state of the unit cell 11 when the usage period of the unit cell 11 is 0 years (for example, the initial stage of manufacture), D10 is the case of the usage period of 10 years, and D25 is the state of the unit cell 11 when the usage period is 25 years. is there.

  As the degradation coefficient η, for example, a value smaller than 1 can be used. As the deterioration of the unit cell 11 progresses, lithium metal may be easily deposited. Therefore, it is preferable to limit the input of the unit cell 11. If the degradation coefficient η, which is a value smaller than 1, is used, the allowable input current value Ilim_d [t] can be made smaller than the allowable input current value Ilim [t], and the input of the unit cell 11 can be limited. . By controlling the input of the cell 11 (the assembled battery 10) based on the allowable input current value Ilim_d [t], it becomes easy to suppress lithium metal deposition.

  In the example of FIG. 3, the deterioration coefficient η is a constant deterioration coefficient η1 (<1) until the use years are 10 years, and after 11 years of use, the value gradually decreases according to the use years. It is set (η2 <η1 <1). In addition, after 25 years of use, the deterioration coefficient η can be a constant value with the deterioration coefficient η2. The correspondence relationship between the degradation coefficient η and the degradation parameter D according to the years of use can be determined based on actual measurement values, experimental measurement values, or the like.

  In this embodiment, the relationship is set such that the larger the deterioration coefficient η, the smaller the battery deterioration, and the smaller the deterioration coefficient η, the larger the battery deterioration. The allowable input current value Ilim_d [t] in consideration of deterioration increases as the battery deterioration is smaller and the larger value of the deterioration coefficient η is applied, and as the battery deterioration is larger, the smaller value of the deterioration coefficient η is applied. The value becomes smaller.

  Next, a method for calculating the deterioration parameter D will be described. The deterioration parameter D is a parameter for specifying the deterioration state of the unit cell 11, and indicates the degree of deterioration according to the charge / discharge history of the unit cell 11 (the assembled battery 10). This parameter can be calculated using, for example, the internal resistance or full charge capacity of the single battery 11. Various methods for specifying the deterioration state (degradation degree) of the unit cell 11 based on the charge / discharge history have been proposed, and the degree of deterioration of the unit cell 11 can be defined by appropriately adopting these methods. .

  The internal resistance R of the cell 11 can be estimated by detecting the current value IB and the voltage value VB of the cell 11. Specifically, the current value IB and the voltage value VB are detected, and the detected current value IB and the voltage value VB are plotted on a coordinate system having the current value and the voltage value as coordinate axes. And if the straight line approximated to a some plot is calculated, the inclination of this approximate straight line can be calculated as the internal resistance (internal resistance calculated value) R of the cell 11.

  It is known that when the cell 11 deteriorates, the internal resistance R increases. For example, with reference to the internal resistance R0 in the initial manufacturing state of 0 years of use, the internal resistance R increases according to the years of use. The degree of deterioration can be correlated. FIG. 4 is a diagram illustrating a correspondence relationship between the internal resistance R and the deterioration parameter D. The numbers given to the internal resistance R indicate the usage period of the assembled battery 10 as in the example of FIG.

  In the example of FIG. 4, for example, a deterioration parameter map in which the deterioration parameter D is associated with each internal resistance R for each service life is created so that the deterioration parameter D increases as the internal resistance R increases. Can do.

  The full charge capacity of the unit cell 11 can be calculated, for example, by integrating the current value IB at this time when the SOC of the unit cell 11 is changed between 0 [%] and 100 [%]. it can. Further, when the SOC of the unit cell 11 is changed within a predetermined range, the full charge capacity of the unit cell 11 can also be calculated by integrating the current value IB at this time.

  When the unit cell 11 deteriorates, the full charge capacity becomes small. Therefore, as in the example of FIG. 4, the decrease in the full charge capacity is correlated with the degree of deterioration based on the full charge capacity in the initial state of the service life of 0 years. The deterioration parameter D can be calculated. For example, it is possible to create a deterioration parameter map in which the deterioration parameter D is associated with each full charge capacity for each service life so that the deterioration parameter D increases as the full charge capacity decreases.

  In addition, when the battery 11 deteriorates, the OCV fluctuation width of the battery 11 with respect to the same fluctuation width (same current cumulative fluctuation width) of the SOC (current integrated value) in charge or discharge is different, and the OCV fluctuation of the single battery 11 with respect to the SOC fluctuation. Becomes larger. Therefore, as in the example of FIG. 4, the deterioration parameter D is calculated by correlating the increase in the OCV fluctuation range with respect to the same fluctuation range of the SOC and the degree of deterioration with reference to the OCV fluctuation range in the initial state of 0 years of use. be able to.

  For example, the deterioration in which the deterioration parameter D is associated with each ratio of the OCV fluctuation to the SOC fluctuation width for each service life so that the deterioration parameter D increases as the ratio of the OCV fluctuation to the SOC fluctuation width increases. A parameter map can be created.

  As described above, if the correspondence relationship between the deterioration parameter D indicating the degree of deterioration and the deterioration coefficient η is obtained in advance, the deterioration parameter η corresponding to the deterioration of the unit cell 11 is specified by calculating (estimating) the deterioration parameter D. can do. Information indicating the correspondence between the deterioration parameter D and the deterioration coefficient η can be stored in the memory 31.

  In this embodiment, the deterioration parameter D based on the charge / discharge history calculated based on the internal resistance R, the full charge capacity, the OCV (OCV fluctuation of the battery 11 with respect to the SOC fluctuation), etc. Correction is performed using the deterioration parameter D ′ based on the moisture permeation history that has permeated into the battery 11, and the deterioration coefficient η is calculated from the map shown in FIG. 3 using the corrected deterioration parameter D (Dh).

  In the following description, a case where the deterioration parameter D based on the internal resistance R of the assembled battery 10 (unit cell 11) is corrected will be described as an example. However, with respect to the deterioration parameter D estimated (calculated) by the various methods described above. However, the same applies.

  It is known that the non-aqueous secondary battery in which the electrolytic solution is composed of a non-aqueous electrolyte deteriorates the battery characteristics due to the permeation of moisture (water vapor) into the inside of the battery. Depending on the amount, moisture permeates into the inside though a small amount. For this reason, it is necessary to consider as a deterioration factor of the cell 11.

  As shown in FIG. 5, the unit cell 11 can be configured by housing a power generation element 200 inside a battery case 110 formed in a rectangular parallelepiped. A battery case 110 formed of metal or the like has a case main body 111 and a lid 112. The case main body 111 has an opening for incorporating the power generation element 200, and the lid 111 is a lid that closes the opening of the case main body 111.

  The positive terminal 120 and the negative terminal 130 are fixed with respect to the lid 111. The positive electrode terminal 120 is electrically connected to the positive electrode current collector 140 housed in the battery case 110, and the positive electrode current collector 140 is electrically connected to the power generation element 200. The negative electrode terminal 130 is electrically connected to the negative electrode current collector 150 housed in the battery case 110, and the negative electrode current collector 150 is electrically connected to the power generation element 200.

  The lid 112 is provided with a valve 113. The valve 113 is used to discharge gas to the outside of the battery case 110 when gas is generated inside the battery case 110. Specifically, when the internal pressure of the battery case 110 reaches the operating pressure of the valve 113 as the gas is generated, the valve 113 changes from a closed state to an open state, thereby discharging the gas to the outside of the battery case 110. Let As the valve 111, a destructive type valve or a return type valve can be used.

  Further, a liquid injection port 114 is formed in the lid 112 at a position adjacent to the valve 113. The liquid injection port 114 is used for injecting an electrolytic solution into the battery case 110. Here, after housing the power generation element 200 in the case main body 111, the lid 112 is fixed to the case main body 111. In this state, the electrolytic solution is injected into the battery case 110 from the liquid injection port 114. After injecting the electrolyte into the battery case 110, the injection port 114 is blocked by the injection plug 115.

  In the example of FIG. 5, for example, inside the unit cell 11 at various locations such as a connection portion between the case body 111 and the lid 112, a connection portion between the positive electrode terminal 120 and the negative electrode terminal 130 provided on the lid 111, the valve 113 and the liquid injection port 114. Design of a seal structure / use of a seal material in consideration of moisture permeation to the cell and electrolyte solution permeation to the outside of the unit cell 11 has been made. However, moisture may permeate into the cell 11 depending on the seal structure or / and the seal material, or in a high temperature and high humidity environment.

  On the other hand, the internal resistance R, the full charge capacity, and the OCV of the single battery 11 may not change greatly with respect to the permeation of moisture into the single battery 11. Since the amount cannot be detected, there is a possibility that the deterioration degree of the single battery 11 cannot be accurately evaluated (understood) only by the deterioration parameter D.

  Therefore, in this embodiment, the moisture permeability (moisture permeation performance) of the entire cell 11 corresponding to the sealing structure (sealing structure) of the cell 11 and the sealing material used for the connection part and the opening part is set in advance. Then, the moisture permeation amount Dw (moisture permeation amount) into the battery is calculated from the temperature TB and humidity WB of the single electricity 11 (the assembled battery 10). Then, the deterioration parameter D ′ is individually obtained as the degree of deterioration of the single battery 11 with respect to the calculated moisture permeation amount Dw, the deterioration parameter D is corrected, and the deterioration coefficient η is calculated based on the corrected deterioration parameter Dh.

  FIG. 6 is a diagram showing the relationship between the performance of moisture permeation into the unit cell 11 per unit time and the temperature. As shown in FIG. 6, the moisture permeation performance of the unit cell 11 depends on the temperature TB, increases as the temperature TB increases, and can be expressed as a function α (TB) that depends on the temperature TB.

  FIG. 7 is a diagram showing the relationship between the moisture permeation amount Dw into the unit cell 11 and the humidity WB based on the moisture permeation performance α (TB) of the unit cell 11 shown in FIG. As shown in FIG. 7, the moisture permeation amount Dw depends on the humidity WB, and increases as the humidity WB increases.

なお、水分透過率（ｇ／ｍ²・ｈ）は、上述のように、単電池１１の内部構造（シール構造／シール材料）から実験や計算により予め求めることができ、水分透過性能α（ＴＢ）は、単電池１１の内部構造毎に異なる。 That is, the moisture permeation amount Dw into the cell 11 can be expressed as a function w that depends on the temperature TB, the humidity WB, and the time Dt.

As described above, the moisture permeability (g / m ² · h) can be obtained in advance by experiments and calculations from the internal structure (seal structure / seal material) of the unit cell 11, and the moisture permeability α (TB) ) Differs for each internal structure of the unit cell 11.

  Further, as shown in FIG. 7, a lower limit value WB0 of humidity for the moisture permeation performance α (TB) can be set. That is, when the humidity permeation performance α (TB) is equal to or lower than the lower limit value WB0 of the humidity, the moisture permeation amount Dw can be calculated as 0, assuming that the moisture does not permeate into the unit cell 11. The lower limit value WB0 of the humidity with respect to the moisture permeability performance α (TB) may be a fixed value or a variable value according to the moisture permeability performance α (TB).

  Therefore, the water permeation performance into the cell 11 is calculated (specific) from the battery temperature TB detected by the temperature sensor 23 based on the correspondence between the water permeation performance α (TB) and the temperature shown in FIG. In addition, based on the calculated moisture permeation performance α (TB), the humidity WB detected by the humidity sensor 24, and the time Dt corresponding to the period for calculating the moisture permeation amount Dw into the unit cell 11, FIG. From the relationship between the moisture permeation amount Dw into the unit cell 11 and the humidity WB based on the moisture permeation performance α (TB) shown in FIG. 5, the moisture permeation amount Dw into the unit cell 11 can be calculated.

  Further, in this embodiment, the moisture permeation amount Dw calculated in each period is integrated, and the deterioration parameter D ′ for the water permeation into the unit cell 11 is calculated using the integrated water permeation amount ΣDw. FIG. 8 is a diagram showing the relationship between the moisture permeation amount ΣDw and the deterioration parameter D ′. When the amount of moisture permeation into the unit cell 11 increases, the deterioration of the battery increases, so that the amount of moisture permeation Dw increases and deteriorates based on the amount of moisture permeation Dw0 in the initial state of use for 0 years (for example, the initial stage of manufacture). The deterioration parameter D ′ can be calculated by correlating the degree. In the present embodiment, the moisture permeation amount from the inside of the cell 11 to the outside is not considered, and the integrated value of the moisture permeation amount ΣDw is a value that does not decrease, that is, the degradation parameter D ′ (second degradation). Degree) is grasped as a degree of deterioration that does not recover.

  Further, the information on the moisture permeation performance α (TB) depending on the temperature TB, the lower limit value WB0 of the humidity with respect to the water permeation performance α (TB), the water permeation amount Dw depending on the humidity WB, and the integrated value ΣDw of the water permeation amount Dw Can be stored in the memory 31.

  FIG. 9 is a diagram illustrating a relationship between the deterioration parameter Dh obtained by adding the deterioration parameter D ′ to the deterioration parameter D corresponding to the increase in the internal resistance R based on the charge / discharge history and the internal resistance R. As shown in FIG. 9, the degree of deterioration is largely reflected by the deterioration parameter D ′ based on the moisture permeation amount Dw to the inside of the unit cell 11. For example, the deterioration parameter D15 for 15 years of use has an increase in the internal resistance R. Even if they are the same, the water permeation amount Dw is increased by the degree of deterioration and becomes the deterioration parameter Dh15.

  In this way, the deterioration parameter D ′ corresponding to the moisture permeation history (water permeation amount Dw) into the unit cell 11 is obtained and added to the deterioration parameter D, whereby the deterioration parameter Dh in consideration of the battery deterioration due to moisture permeation is obtained. Calculation (correction) is performed, and the deterioration coefficient η is calculated based on the deterioration parameter Dh.

  That is, in this embodiment, when the allowable input current value Ilim [t] is updated, the allowable input current value Ilim [t] is applied by applying the deterioration coefficient η (<1) according to the deterioration state of the battery pack 10. While controlling the charge (input) of the battery pack 10 while reducing the level, the deterioration degree based on the charge / discharge history (corresponding to the first deterioration degree) and the deterioration degree based on the moisture permeation history (second deterioration degree) Thus, the reduction rate (deterioration coefficient η) when the allowable input current value Ilim [t] is reduced can be changed.

  Therefore, the allowable input current value Ilim [t] can be corrected by the deterioration coefficient η in consideration of the battery deterioration due to moisture permeation into the battery in Expression (4). In other words, it is possible to calculate the allowable input current value Ilim_d [t] in consideration of battery deterioration due to moisture permeation.

  In addition, when the deterioration parameter D ′ according to the moisture permeation history into the unit cell 11 is small, the deterioration parameter D according to the charge / discharge history may not be significantly affected. In this case, even if the deterioration parameter D is corrected using the deterioration parameter D ′, the same deterioration coefficient η corresponding to the deterioration parameter D before correction is calculated.

  Further, in this embodiment, after the deterioration parameter D ′ is corrected using the deterioration parameter D ′, the corrected deterioration coefficient η is calculated as in the example of FIG. Apart from the degradation coefficient η, the degradation coefficient η ′ for the degradation parameter D ′ can be calculated. In this case, the deterioration factor η ′ is added to, subtracted from, or multiplied by the deterioration factor η to calculate the corrected deterioration factor ηh, and the battery deterioration due to moisture permeation to which the deterioration factor ηh is applied in the equation (4) is taken into consideration. The allowable input current value Ilim_d [t] may be calculated.

  FIG. 10 is a diagram showing a moisture permeation amount calculation process flow for calculating the moisture permeation amount Dw into the single cell 11 (the assembled battery 10) in the battery system of the present embodiment. 30.

  The moisture permeation amount calculation process can be performed, for example, at a predetermined time interval. Each of the period from when the ignition switch of the vehicle is turned on to when it is turned off, and the period after the ignition switch is turned off until it is turned on, respectively. In the above, it can be performed at predetermined time intervals. Moreover, the process which controls charging / discharging of the assembled battery 10 mentioned later is performed independently.

  In step S <b> 101, the controller 30 detects the battery temperature TB of the assembled battery 10 (unit cell 11) based on the output of the temperature sensor 23. Further, based on the output of the humidity sensor 24, the humidity WB around the assembled battery 10 (unit cell 11) is detected.

  In step S102, the controller 30 calculates the moisture permeation performance α (TB) of the assembled battery 10 corresponding to the detected humidity WB. As described above, the moisture permeation performance α (TB) is set in advance according to the seal structure / seal material of the unit cell 11 as shown in FIG. 6, so the battery temperature TB detected in step S101 is determined. Can be used to calculate.

  In step S103, the controller 30 uses the calculated moisture permeation performance α (TB), humidity WB, and time (elapsed time from the previous calculation timing to the current calculation timing) to permeate the inside of the unit cell 11. A moisture permeation amount Dw is calculated.

  The controller 30 adds the moisture permeation amount Dw (n) calculated in step S103 to the previously calculated moisture permeation amount Dw (n−1) to calculate a moisture permeation amount integrated value ΣDw (n). n indicates the number of calculations.

  Next, a process for controlling charging / discharging of the assembled battery 10 in the battery system of the present embodiment will be described. FIG. 11 is a flowchart illustrating a process for setting the allowable input current value Ilim. The process shown in FIG. 11 is executed by the controller 30.

  In step S <b> 301, the controller 30 detects the current value IB of the assembled battery 10 based on the output of the current sensor 22. Further, the controller 30 detects the temperature TB of the assembled battery 10 based on the output of the temperature sensor 23. Further, the controller 30 detects the voltage VB of the assembled battery 10 based on the output of the monitoring unit 21. In step S302, the controller 30 estimates the SOC of the battery pack 10. The method for estimating the SOC is as described above.

  In step S <b> 303, the controller 30 calculates the service life of the assembled battery 10. The service life of the assembled battery 10 can be measured with a system timer or the like built in or externally attached to the controller 30 based on, for example, the service life of 0 years (initial stage of manufacture). 31 can be stored (updated). The controller 30 acquires the number of years of use (for example, yearly) from the memory 31.

  In step S304, the controller 30 calculates the internal resistance R of the unit cell 11 based on the detected current value IB and voltage value VB. The method for calculating the internal resistance R is as described above.

  Next, the controller 30 calculates the deterioration parameter D in step S305. The controller 30 calculates the deterioration parameter D from the correspondence relationship between the deterioration parameter D and the internal resistance R shown in FIG.

  In step S306, the controller 30 performs. In order to calculate the deterioration parameter D ′ with respect to the moisture permeation amount Dw into the assembled battery 10, the latest accumulated value ΣDw of the moisture permeation amount stored in the memory 31 is acquired. Here, the controller 30 can acquire the integrated value ΣDw of the moisture permeation amount calculated up to the most recent calculation timing in the moisture permeation amount calculation process executed independently of the present process.

  In step S307, the controller 30 calculates the deterioration parameter D ′ from the correspondence relationship between the deterioration parameter D ′ and the water transmission amount integrated value ΣDw shown in FIG. 8 using the acquired integrated value ΣDw of the water transmission amount.

  In step S308, the controller 30 corrects the deterioration parameter D of the assembled battery 10 based on the internal resistance R using the calculated deterioration parameter D ′, and calculates the corrected deterioration parameter Dh. For example, the deterioration parameter Dh can be calculated by adding the deterioration parameter D ′ to the deterioration parameter D. It should be noted that the deterioration parameter D ′ in the initial state of the assembled battery 10 having a service life of 0 can be set to 0 assuming that there is no battery deterioration with respect to the amount of moisture permeated into the assembled battery 10. For this reason, even if the deterioration parameter D ′ is added, the deterioration parameter D and the deterioration parameter Dh may be equal.

  In step S309, the controller 30 calculates the deterioration coefficient η of the battery pack 10 in consideration of moisture permeation into the battery using the deterioration parameter Dh.

  In step S310, the controller 30 calculates the allowable input current value Ilim [t] based on the above equation (2).

  The allowable input current value Ilim [t] is calculated at a predetermined cycle when the assembled battery 10 is charged / discharged or when the assembled battery 10 is left unattended. That is, the allowable input current value Ilim [t] is updated each time a predetermined time corresponding to the interval between the time t and the time “t−1” elapses. Here, the allowable input current value Ilim [t] is used only when controlling the charging of the battery pack 10.

  In step S311, the controller 30 calculates the allowable input current value Ilim_d [t] based on the above equation (4). Here, as the allowable input current value Ilim [t] shown in the above equation (4), the allowable input current value Ilim [t] calculated in the process of step S310 is used. Further, the deterioration coefficient η is the one calculated in step S309.

  After calculating the allowable input current value Ilim_d [t], the controller 30 controls input / output (charging / discharging) of the assembled battery 10 based on the allowable input current value Ilim_d [t]. Here, when the input of the assembled battery 10 is controlled, the input limit value (power) Win [t] is set, and the assembled battery 10 is set so that the input power of the assembled battery 10 does not exceed the input limit value Win [t]. Is controlled. The input limit value Win [t] can be set as described below, for example.

  First, the controller 30 calculates the input current limit value Itag based on the allowable input current value Ilim_d [t]. The input current limit value Itag is a value for specifying the input limit value Win [t]. Specifically, the controller 30 calculates the input current limit value Itag by offsetting the allowable input current value Ilim_d [t] by a predetermined amount toward 0 [A]. Thereby, the input current limit value Itag becomes a value closer to 0 [A] than the allowable input current value Ilim_d [t], and the input of the assembled battery 10 is easily limited.

  By providing a margin between the allowable input current value Ilim_d [t] and the input current limit value Itag, it is possible to make it difficult for the current value IB to exceed the allowable input current value Ilim_d [t]. When controlling the input of the assembled battery 10 based on the input current limit value Itag, when the current value IB reaches the input current limit value Itag, the input restriction of the assembled battery 10 is started. Here, even if the current value IB exceeds the input current limit value Itag due to a control delay or the like, it is possible to suppress the current value IB from reaching the allowable input current value Ilim_d [t].

  Next, the controller 30 calculates the input limit value Win [t] based on the input current limit value Itag. If the input current limit value Itag is set, the input limit value Win [t] can be set. When the input limit value Win [t] is set, the controller 30 adjusts the torque command of the motor / generator 25 so that the input power of the assembled battery 10 is equal to or less than the input limit value Win [t].

  For example, the input limit value Win [t] can be calculated based on the following formula (6).

  In the above equation (6), SWin [t] is an input limit value Win set in advance in consideration of the input characteristics of the assembled battery 10 and the like. Information regarding the input limit value SWin [t] can be stored in the memory 31.

  The input limit value SWin [t] can be changed according to the battery temperature TB or SOC, for example. Specifically, the input limit value SWin [t] can be decreased as the battery temperature TB increases, or the input limit value SWin [t] can be decreased as the battery temperature TB decreases. Further, the input limit value SWin [t] can be decreased as the SOC increases. If the correspondence between the input limit value SWin [t] and the battery temperature TB (or / and SOC) is obtained in advance, the input limit value SWin [t is detected by detecting the battery temperature TB (or / and SOC). ] Can be specified.

  In the above equation (6), Kp and Ki indicate preset gains. Itag1 and Itag2 indicate input current limit values and correspond to the above-described input current limit value Itag. In the above equation (5), two input current limit values Itag1, Itag2 are set as the input current limit value Itag. Here, the input current limit values Itag1 and Itag2 may be equal to each other or different from each other.

  In the above description, the input current limit value Itag is set, but the present invention is not limited to this. Specifically, the input limit value Win [t] can be set based on the allowable input current value Ilim_d [t] without setting the input current limit value Itag.

  According to the present embodiment, the allowable input current value Ilim [t] is set in consideration of the decrease amount per unit time and the recovery amount per unit time as shown in the above formula (2). Thereby, the allowable input current value Ilim [t] can be set in consideration of the charge / discharge history of the unit cell 10 up to the present time. Then, by controlling the input of the assembled battery 10 based on the allowable input current value Ilim [t], it is possible to suppress the negative electrode potential from being lower than that of the reference battery.

  In the present embodiment, the deterioration parameter D ′ for evaluating the deterioration degree based on the moisture permeation history into the assembled battery 10 is separately provided from the deterioration parameter D representing the deterioration degree of the assembled battery 10 based on the charge / discharge history. The deterioration parameter D is calculated and corrected. For this reason, in addition to the battery deterioration based on the charge / discharge history, the allowable input current value Ilim_d [t] can be set using the deterioration coefficient η corresponding to the battery deterioration in consideration of moisture permeation into the assembled battery 10. The overcharge can be suppressed and the assembled battery 10 can be protected appropriately.

  In other words, the rate of change of the allowable input current corresponding to the battery deterioration of only the charging / discharging history of the assembled battery 10 is changed to a lower rate in consideration of moisture permeation into the assembled battery 10. Accordingly, it is possible to appropriately suppress the corresponding overcharge, and it is possible to suppress the negative electrode potential from being lower than that of the reference battery. On the other hand, if the moisture permeation into the assembled battery 10 is sufficiently small, the allowable input current value Ilim_d [t] can be set at the rate of decrease in the allowable input current corresponding to the battery deterioration of only the charge / discharge history of the assembled battery 10. For example, it can control so that the input of the assembled battery 10 may not be suppressed excessively except in the environment of high temperature and humidity.

  12 and 13 are diagrams showing a modification of the present embodiment. FIG. 12 is a flowchart for explaining the process of setting the allowable input current value Ilim. In the process shown in FIG. 11, correction by applying the deterioration parameter D ′ based on the moisture permeation amount Dw into the assembled battery 10 is performed. It is made variable according to the internal resistance R.

  The internal resistance R of the assembled battery 10 (unit cell 11) is worn out and deteriorated as charging / discharging continues, and its value increases. The secular change of wear deterioration of the internal resistance R can be predicted in advance based on actual measurement or calculation according to the usage time of the assembled battery 10. FIG. 13 is a diagram illustrating the relationship between the usage time and the predicted value of the internal resistance R over time.

  Therefore, in the present modification, the predicted value Rf of the internal resistance corresponding to the usage time of the assembled battery 10 is calculated from the correspondence relationship in FIG. 13 in step S3051, and the actual value calculated in step S304 in step S3052. The internal resistance R is compared.

  When the internal resistance R, which is an actually measured value, is larger than the predicted value Rf, the controller 50 proceeds to step S306, performs correction using the deterioration parameter D ′ based on the moisture permeation amount Dw into the assembled battery 10, and performs a deterioration coefficient. η is calculated. On the other hand, when the internal resistance R that is an actual measurement value is smaller than the predicted value Rf, the deterioration parameter D ′ based on the moisture permeation amount Dw into the assembled battery 10 is not applied (without correction), and the deterioration parameter D The degradation coefficient η based only on

  With this configuration, when the degree of deterioration of the internal resistance R is smaller than the predicted value Rf, that is, when it is determined that the battery deterioration is small, the allowable input current value Ilim [t based on the moisture permeation amount Dw ] Can be relaxed and excessive restrictions can be suppressed. In other words, when the degree of deterioration of the internal resistance R is larger than the predicted value Rf, by limiting the allowable input current value Ilim [t] based on the moisture permeation amount Dw, the battery deterioration of the assembled battery 10 can be prevented. Appropriate input restrictions can be made.

  In the present embodiment, the assembled battery 10 is mounted on a vehicle, but the present invention is not limited to this. That is, the present invention can be applied to any system that controls the charging of a lithium ion secondary battery in order to suppress lithium metal deposition.

10: assembled battery 11: single cell 21: monitoring unit,
22: current sensor 23: temperature sensor 24: inverter
25: Motor generator 30: Controller 31: Memory PL: Positive line, NL: Negative line C: Capacitors SMR-B, SMR-G, SMR-P: System main relay R: Current limiting resistor

Claims (7)

A controller that controls the input of the non-aqueous secondary battery while lowering the allowable input current value, which is the maximum current value allowing the input of the non-aqueous secondary battery, according to the deterioration state of the non-aqueous secondary battery. Have
The controller is
When the allowable input current value is decreased according to the first deterioration degree based on the charge / discharge history of the non-aqueous secondary battery and the second deterioration degree based on the moisture permeation history into the non-aqueous secondary battery. A battery system characterized by changing the rate of decrease of the battery.   The battery system according to claim 1, wherein the moisture permeation history depends on a battery temperature and an ambient humidity of the non-aqueous secondary battery. A temperature sensor for detecting a battery temperature of the non-aqueous secondary battery;
A humidity sensor for detecting the humidity around the non-aqueous secondary battery,
The controller calculates the moisture permeation amount according to the detected humidity based on the moisture permeability into the non-aqueous secondary battery depending on the detected battery temperature at a predetermined timing, The battery system according to claim 2, wherein a moisture permeation amount integrated value obtained by integrating the moisture permeation amount calculated at each timing is calculated as the moisture permeation history.   4. The controller according to claim 1, wherein the controller corrects the first deterioration degree according to the second deterioration degree, and changes the reduction rate based on the corrected first deterioration degree. 5. The battery system according to any one of the above. A current sensor for detecting a current value of the non-aqueous secondary battery;
A voltage sensor for detecting a voltage value of the non-aqueous secondary battery,
The controller is
When the first deterioration degree corresponding to the charge / discharge history of the non-aqueous secondary battery based on the detected current value and voltage value is smaller than a predicted deterioration degree preset for the non-aqueous secondary battery 5. The battery system according to claim 1, wherein a rate of decrease when the allowable input current value is decreased is changed according to only the first deterioration level. 6. The non-aqueous secondary battery is a lithium ion secondary battery,
6. The controller according to claim 1, wherein the controller sets the allowable input current value so that a negative electrode potential of the lithium ion secondary battery does not fall below a reference potential that regulates lithium metal deposition. The battery system as described in any one. Control for controlling the input of the non-aqueous secondary battery while lowering the allowable input current value, which is the maximum current value allowing the input of the non-aqueous secondary battery, according to the deterioration state of the non-aqueous secondary battery A method,
When the allowable input current value is decreased according to the first deterioration degree based on the charge / discharge history of the non-aqueous secondary battery and the second deterioration degree based on the moisture permeation history into the non-aqueous secondary battery. A control method characterized by changing the rate of decrease of the above.

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