JP7208272B2 - Controller and its use - Google Patents

Description

The present invention relates to a control device and its use.

Japanese Patent Application Laid-Open No. 2016-225206 discloses a method of estimating the state of deterioration of a secondary battery in use based on the salt concentration of the electrolyte in the secondary battery. In the method described in the publication, first, the volume expansion rate of the electrode body is calculated based on the temperature change and the SOC (state of charge) change of the secondary battery in use, and then the salt concentration of the electrolyte is calculated. do. Then, the amount of increase in the internal resistance of the secondary battery is calculated from the calculated value of the salt concentration. Then, it is proposed to control charging and discharging of the secondary battery based on the calculated amount of increase in internal resistance.

On the other hand, Japanese Patent No. 6447029 discloses a method of estimating the deterioration state of a secondary battery having a battery case due to gas generation in the battery case as the expansion amount of the secondary battery. In the method described in the publication, the swelling amount of the secondary battery to be estimated is calculated based on the temperature, SOC, and the like of the secondary battery. Then, it is proposed to stop energization of the secondary battery based on the calculated swelling amount.

JP 2016-225206 A Japanese Patent No. 6447029

By the way, the present inventor wishes to estimate the state of deterioration during use of a non-aqueous electrolyte secondary battery in which an electrode assembly and an electrolyte are housed in a battery case with higher accuracy.

The control device disclosed herein estimates the deterioration state of a non-aqueous electrolyte secondary battery in which an electrode body in which a positive electrode sheet and a negative electrode sheet are stacked with a separator interposed therebetween and an electrolyte is housed in a battery case. It is a control device. This control device prepares a deterioration estimation map for estimating the deterioration of the non-aqueous electrolyte secondary battery, which is selected based on the impregnation state of the electrolyte into the electrode body in the initial state of the non-aqueous electrolyte secondary battery. I remember. This control device is configured to estimate the deterioration state of the non-aqueous electrolyte secondary battery based on the deterioration estimation map. According to the control device having such a configuration, the degradation estimation map is selected based on the impregnation state of the electrolyte into the electrode body in the initial state of the non-aqueous electrolyte secondary battery to be estimated. , the deterioration state of the non-aqueous electrolyte secondary battery can be estimated with higher accuracy.

The deterioration estimation map may record the relationship between the temperature, SOC, and deterioration coefficient of the non-aqueous electrolyte secondary battery. According to such a configuration, the deterioration state of the non-aqueous electrolyte secondary battery can be estimated with higher accuracy.

The control device further stores a control map for determining control values for charging and discharging the non-aqueous electrolyte secondary battery based on the deterioration state of the non-aqueous electrolyte secondary battery derived based on the deterioration estimation map. good too. Here, the control device may be configured to control charging and discharging of the non-aqueous electrolyte secondary battery based on the deterioration state estimated based on the deterioration estimation map and the control map. With such a configuration, it is possible to better control charging and discharging of the non-aqueous electrolyte secondary battery.

A plurality of degradation estimation maps may be stored in advance in the control device. Here, based on the impregnation state of the electrolyte into the electrode body in the initial state of the non-aqueous electrolyte secondary battery to be controlled, the control device selects the non-aqueous electrolyte to be controlled from among the plurality of deterioration estimation maps. It may be configured such that a deterioration estimation map suitable for the liquid secondary battery is selected. According to such a configuration, the deterioration state of the non-aqueous electrolyte secondary battery can be estimated with higher accuracy.

As another form, the control device may store in advance a reference deterioration estimation map and a plurality of correction maps for correcting the reference deterioration estimation map. Here, the control device corrects the reference degradation estimation map among the plurality of correction maps based on the impregnation state of the electrolyte into the electrode body in the initial state of the non-aqueous electrolyte secondary battery to be controlled. It may be configured such that a correction map for is selected. According to such a configuration, it becomes easier to optimize the deterioration estimation map in order to estimate the deterioration state of the non-aqueous electrolyte secondary battery to be controlled.

The deterioration estimation map may also be selected based on the internal pressure in the initial state of the non-aqueous electrolyte secondary battery. The present inventors have found that the internal pressure of a non-aqueous electrolyte secondary battery can contribute to deterioration of the battery. Therefore, according to such a configuration, the deterioration state of the non-aqueous electrolyte secondary battery can be estimated with higher accuracy.

The secondary battery system disclosed herein includes an electrode body in which a positive electrode sheet including a positive electrode active material layer and a negative electrode sheet including a negative electrode active material layer are stacked with a separator interposed therebetween; an electrolyte; a secondary battery comprising a battery case containing an electrolytic solution; charging and discharging means for charging and discharging the secondary battery; and the control device. In the secondary battery system, the state of deterioration of the non-aqueous electrolyte secondary battery can be estimated with higher accuracy. Therefore, charging and discharging of the non-aqueous electrolyte secondary battery can be controlled more appropriately according to the state of deterioration of the battery.

1 is a block diagram of a control device according to one embodiment; FIG. 1 is a cross-sectional view schematically showing the configuration of a non-aqueous electrolyte secondary battery; FIG. It is an image which shows the electrode body of the impregnation initial stage. 10 is an image showing an electrode body in the middle stage of impregnation. It is an image which shows the electrode body in the final stage of impregnation. 4 is a matrix diagram showing an example of deterioration estimation map MP1. FIG. 4 is a graph showing the correlation between the internal pressure and the time from electrolyte injection to sealing. 7 is an example of a graph showing the time transition of the resistance increase rate in Test Example 1. FIG. 10 is an example of a graph showing temporal transition of resistance increase rate in Test Example 2. FIG. It is a flowchart explaining the control method using the control apparatus which concerns on one Embodiment.

An embodiment of the present invention will be described below. In the drawings below, members and portions having the same function are denoted by the same reference numerals. Also, the dimensional relationships (length, width, thickness, etc.) in the drawings do not reflect the actual dimensional relationships. In this specification, the term "secondary battery" generally refers to an electricity storage device that can be repeatedly charged and discharged, and includes so-called storage batteries (i.e., chemical batteries) such as lithium-ion secondary batteries, nickel-hydrogen batteries, and nickel-cadmium batteries. In addition, capacitors such as electric double layer capacitors (that is, physical batteries) are included.
In the present specification, the notation of "A to B" indicating a numerical range means from A to B and includes those exceeding A and below B.

FIG. 1 is a block diagram of a control device according to one embodiment. As shown in FIG. 1 , secondary battery system 1 includes secondary battery 100 , charging/discharging means 200 , and control device 300 . The secondary battery 100 is a so-called non-aqueous electrolyte secondary battery including an electrode assembly, an electrolyte (non-aqueous electrolyte), and a battery case. The type of the secondary battery 100 is not particularly limited as long as it has at least the above configuration, and is, for example, a lithium ion secondary battery.

FIG. 2 is a cross-sectional view schematically showing the configuration of a non-aqueous electrolyte secondary battery. As shown in FIG. 2, a secondary battery 100 (hereinafter also referred to as "non-aqueous electrolyte secondary battery 100") includes a flat-shaped wound electrode body 20 (hereinafter, simply Also referred to as “electrode body 20 ”) and a non-aqueous electrolyte (not shown) are housed in a flat rectangular battery case (that is, outer container) 30 . The battery case 30 is provided with a positive terminal 42 and a negative terminal 44 for external connection, and a thin safety valve 36 that is set to release the internal pressure of the battery case 30 when it rises above a predetermined level. It is The positive and negative terminals 42 and 44 are electrically connected to the positive and negative current collecting plates 42a and 44a, respectively.

The electrode body 20 has a configuration in which a positive electrode sheet 50 and a negative electrode sheet 60 are superimposed with two long separator sheets 70 interposed therebetween and wound in the longitudinal direction. The positive electrode sheet 50 has a configuration in which a positive electrode active material layer 54 is formed along the longitudinal direction on one side or both sides (here, both sides) of a long positive electrode current collector 52 . The negative electrode sheet 60 has a configuration in which a negative electrode active material layer 64 is formed along the longitudinal direction on one side or both sides (here, both sides) of a long negative electrode current collector 62 . The positive electrode active material layer non-formed portion 52a (that is, the portion where the positive electrode current collector 52 is exposed without the positive electrode active material layer 54 being formed) and the negative electrode active material layer non-formed portion 62a (that is, the negative electrode active material layer 64 is formed). The portion where the negative electrode current collector 62 is exposed without being wound) is formed so as to protrude outward from both ends of the electrode assembly 20 in the winding axial direction (that is, the sheet width direction perpendicular to the longitudinal direction). A positive collector plate 42a and a negative collector plate 44a are joined to the positive electrode active material layer non-formed portion 52a and the negative electrode active material layer non-formed portion 62a, respectively. In addition, regarding the constituent materials of the battery case and the electrode body, etc., those used in this type of secondary battery can be used without particular limitation, and they do not characterize the present invention. Description is omitted.

The charging/discharging means 200 is configured to charge and discharge the non-aqueous electrolyte secondary battery 100 . The charging/discharging means 200 only needs to be capable of charging/discharging the non-aqueous electrolyte secondary battery 100, and any means used for charging/discharging this type of secondary battery can be used without particular limitation. Since the structure of the charging/discharging means 200 itself does not characterize the present invention, detailed description thereof is omitted here.

The control device 300 is configured to estimate the deterioration state of the non-aqueous electrolyte secondary battery 100 and control charging and discharging. The control device 300 includes a CPU that executes a processing program, a ROM that stores the processing program, a RAM that temporarily stores data, an input/output port, a communication port, and various sensors. Each configuration and processing of the control device 300 is implemented by a database that stores data embodied by a computer in a predetermined format, a data structure, a processing module that performs predetermined arithmetic processing according to a predetermined program, or It can be embodied as part of them. Also, the processing of the control device 300 may be performed in cooperation with such an external computer. For example, the information or part of the information stored in the control device 300 may be stored by an external computer, or the processing or part of the processing executed by the control device 300 may be executed by an external computer. good.

The control device 300 includes functional blocks for estimating the deterioration state of the non-aqueous electrolyte secondary battery 100 and controlling charging and discharging, including a detection unit, a battery information acquisition unit, a map information storage unit, and a deterioration state estimation unit. , a storage unit, and a control unit.

The detection unit is configured to detect the current value (Ib), voltage value (Vb), and temperature (Tb) of the non-aqueous electrolyte secondary battery 100. A first detection unit 301 and a second detection unit 302 and a third detector 303 . The first detection unit 301 is connected to an ammeter (not shown) connected in series with the non-aqueous electrolyte secondary battery 100, and can detect a current value (Ib). The second detection unit 302 is connected to a voltmeter (not shown) that is connected in parallel with the non-aqueous electrolyte secondary battery 100, and can detect a voltage value (Vb). The third detector 303 is connected to a temperature sensor (not shown) and can detect temperature (Tb).

The SOC acquisition unit 304 is configured to acquire the SOC of the non-aqueous electrolyte secondary battery 100 . The SOC is represented, for example, by a charging rate with a fully charged state as 100%. For example, the current SOC is grasped by monitoring the amount of electricity charged and discharged from the initial state of the non-aqueous electrolyte secondary battery 100 . The SOC acquisition unit is configured to constantly record the current value (Ib) detected by the first detection unit 301 and to calculate the charge quantity and the discharge quantity of electricity from the initial state.

Map information storage unit 305 stores at least deterioration estimation map MP1 for estimating deterioration of non-aqueous electrolyte secondary battery 100 . The deterioration estimation map MP1 is selected based on the impregnation state of the electrolyte into the electrode body 20 in the initial state of the non-aqueous electrolyte secondary battery 100 . The map information storage unit 305 can have a plurality of deterioration estimation maps MP1. In this case, it is preferable to select one of the plurality of deterioration estimation maps MP1 corresponding to the impregnation state of the electrolyte into the electrode body 20 in the initial state. The “initial state” refers to the state after manufacturing the battery assembly and subjecting the battery assembly to initial charging and aging treatment (that is, after constructing a usable non-aqueous electrolyte secondary battery). It refers to the state before being installed in the battery pack.

The impregnation state of the electrolyte into the electrode body 20 of the non-aqueous electrolyte secondary battery 100 in the initial state is calculated by calculating the attenuation rate of ultrasonic waves output toward the non-aqueous electrolyte secondary battery 100. can be estimated by The method for calculating such an ultrasonic attenuation factor is known and not particularly limited, but for example, an ultrasonic output unit and an ultrasonic receiving unit as described in Japanese Patent Application Laid-Open No. 2015-197968. A method of using an impregnation inspection device provided with can be adopted.

An example of a method for estimating the impregnation state of the electrolyte into the electrode body of the non-aqueous electrolyte secondary battery 100 will be described below, but it is not intended to be limited to such an estimation method. The non-aqueous electrolyte secondary battery 100 is sandwiched between the ultrasonic wave output section and the ultrasonic wave receiving section so as to sandwich the wide surface of the electrode body 20, and the ultrasonic wave is output from the ultrasonic wave output section. The output ultrasonic waves pass through the non-aqueous electrolyte secondary battery 100 and are received by the ultrasonic wave receiving section. Here, when the electrode body is impregnated with the electrolytic solution, air bubbles in the electrode body are released to the outside. Ultrasonic waves are attenuated because they are reflected when they hit air bubbles. As the electrode body is impregnated with the electrolytic solution, the number of air bubbles in the electrode body is reduced, so that the ultrasonic wave received by the ultrasonic wave receiving section is attenuated. By calculating the ratio of the received ultrasonic waves to the output ultrasonic waves, the ultrasonic attenuation factor can be calculated. Then, the amount of change in the ultrasonic attenuation rate per unit time is monitored, and it can be determined that the impregnation is completed when the amount of change becomes equal to or less than a threshold value (for example, zero).

As described above, in a state in which it is confirmed that the amount of change in the ultrasonic attenuation rate is equal to or less than the threshold value and that the impregnation of the electrode body with the electrolytic solution is completed, the intensity of the output ultrasonic wave It and the intensity of the received ultrasonic wave are from Ir,
Formula (1) below:
Impregnation rate of electrolytic solution (%) = Ir/It x 100 (1)
can be used to calculate the impregnation rate of the electrolytic solution.

The impregnation state of the electrode body with the electrolytic solution can be divided into the initial stage of impregnation, the middle stage of impregnation, and the final stage of impregnation. For example, the initial stage of impregnation refers to a state in which the impregnation rate of the electrolyte into the electrode body is less than 30%. The middle stage of impregnation refers to a state in which the impregnation rate of the electrolytic solution into the electrode body is 30% or more and less than 70%. The final stage of impregnation refers to a state in which the impregnation rate of the electrolytic solution into the electrode body is 70% or more. In addition, FIG. 3 is an image showing the electrode body in the initial stage of impregnation. FIG. 4 is an image showing the electrode assembly in the middle stage of impregnation. FIG. 5 is an image showing the electrode assembly at the end of impregnation.

FIG. 6 is a matrix diagram showing an example of the deterioration estimation map MP1. The deterioration estimation map MP1 describes, for example, the relationship between the temperature, SOC, and deterioration coefficient of the non-aqueous electric field secondary battery. In this case, the deterioration estimation map MP1 is composed of a matrix in which the vertical axis represents the battery temperature and the horizontal axis represents the SOC. Coefficients should be recorded. For example, assuming a non-aqueous electrolyte secondary battery that is used while mounted on a vehicle, in actual use in a vehicle, the non-aqueous electrolyte secondary battery has a predetermined SOC of about 10% to 90%. Used in charging state. In actual use in vehicles, the non-aqueous electrolyte secondary battery can be placed in a temperature environment of about -40°C to 60°C. It is preferable to determine the deterioration coefficient by predicting the resistance increase rate when the actual use of such a vehicle continues for about 10 years or about 25 years.

The deterioration coefficient can be obtained, for example, by conducting a test using a test secondary battery under predetermined conditions. Such a test can be set so that the rate of increase in resistance of the secondary battery for testing can be predicted when actual use in a vehicle continues for about 10 years or about 25 years. Here, assuming that the resistance value in the initial state of the test secondary battery used in the test is R0, and the resistance value R1 of the test secondary battery after the test is energized for a predetermined period T, the above deterioration The coefficient is, for example, the resistance increase rate per unit time,
Formula (2) below:
Deterioration coefficient = (R1/R0-1)/√T (2)
can be calculated by For the conditions of the above test, refer to the test examples described later.

An example of a test method using a test secondary battery (that is, a method of creating a deterioration estimation map MP1) will be described below together with the results of studies by the inventors.

<Test Example 1: Effect of internal pressure on deterioration of non-aqueous electrolyte secondary battery>
In Test Example 1, a secondary battery for evaluation whose internal pressure was adjusted to be positive pressure and a secondary battery for evaluation whose internal pressure was adjusted to be negative pressure were prepared, and an electric current test was performed. The time transition of the rate of increase was evaluated.
<1. Preparation of secondary battery for evaluation>
First, a secondary battery for evaluation was prepared.
LiNi _1/3 Co _1/3 Mn _1/3 O ₂ as a positive electrode active material, acetylene black (AB) as a conductive material, and polyvinylidene fluoride (PVDF) as a binder were combined into a positive electrode active material: AB: A slurry for forming a positive electrode active material layer was prepared by mixing in N-methylpyrrolidone (NMP) at a mass ratio of PVDF=94:3:3 using a planetary mixer. This slurry was applied to both sides of an aluminum foil having a thickness of 15 μm and dried. After that, a positive electrode sheet was produced by pressing this. In addition, natural graphite (C) as a negative electrode active material, styrene-butadiene rubber (SBR) as a binder, and carboxymethyl cellulose (CMC) as a thickening agent were mixed in a ratio of C: SBR: CMC = 98: 1: 1. A slurry for forming a negative electrode active material layer was prepared by mixing in ion-exchanged water at a mass ratio. This slurry was applied to both sides of a copper foil having a thickness of 10 μm and dried. Then, a negative electrode sheet was produced by pressing this. Also, two separator sheets (a separator sheet in which a heat-resistant layer is formed on a porous polyolefin sheet having a three-layer structure of PP/PE/PP with a thickness of 20 μm) were prepared.

The prepared positive electrode sheet, negative electrode sheet, and two prepared separator sheets were superimposed and wound to prepare a wound electrode assembly. Electrode terminals were attached by welding to the positive electrode sheet and the negative electrode sheet of the wound electrode body thus produced. This was housed in a battery case having an injection port. Subsequently, a non-aqueous electrolyte was injected from the liquid inlet of the battery case, and the liquid inlet was airtightly sealed. Here, secondary batteries for evaluation (hereinafter also referred to as "sample batteries") having different internal pressures were produced by varying the timing from the injection of the electrolyte solution to the sealing of the injection hole.

The non-aqueous electrolyte was a mixed solvent containing ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate (EMC) at a volume ratio of 30:40:30, and LiPF ₆ as a supporting salt at a concentration of 1.2 M. A dissolved one was used. The electrolytic solution contained 0.08 M of P1 and 0.023 M of LiBOB (lithium bisoxalate borate) as additives.

<2. Measurement of internal pressure>
The internal pressure of the sample battery was measured. FIG. 7 is a graph showing the correlation between the internal pressure and the time from injection of the electrolytic solution to sealing. In FIG. 7, the dotted line indicates the atmospheric pressure. That is, an internal pressure higher than the dotted line indicates positive pressure, and an internal pressure lower than the dotted line indicates negative pressure. Moreover, the internal pressure was measured by attaching a pressure sensor to the side surface of the sample battery and converting the voltage detected by the pressure sensor into an internal pressure.

<3. Measurement of initial resistance>
The initial resistance of the sample battery was then obtained. After initial charging of the sample battery, it was stored in a constant temperature bath at 60° C. for 24 hours. The sample battery was discharged at a current value of 130 A for 10 seconds, the voltage value was measured 10 seconds after the start of discharge, and the initial resistance was calculated. The initial resistance was measured by exposing one sample battery to temperature environments of 25°C, -10°C, -30°C, and -40°C, and changing the SOC of the sample battery to 10%, 20%, 30%, and 30% for each temperature. It was obtained by adjusting to 60% and performing the above discharge. Although the internal pressure of the battery and the impregnation state of the electrolyte into the electrode body are not mentioned, in the following test examples, when obtaining the resistance value of the sample battery, the procedure for obtaining the initial resistance of the sample battery was used. went. In the following test examples, the resistance increase rate for each resistance value obtained as described above was obtained.

<4. Electrical test>
From the sample batteries prepared as described above, those with positive internal pressure and those with negative internal pressure were selected. The SOC of these sample batteries was adjusted to 60%, placed in a test temperature environment of 40° C., and a cycle test (that is, energization) was performed on the sample batteries according to a predetermined cycle pattern. The resistance value of the sample battery was measured once every 20 cycles. The measurement conditions were the same procedure as the measurement of the initial resistance, but the temperature during the measurement was 25° C. and the SOC was 56%. Then, energization and resistance values were obtained up to the number of cycles corresponding to 10 years or 25 years of normal use of the non-aqueous electrolyte secondary battery. From the obtained resistance value, the resistance increase rate (that is, an example of the deterioration coefficient) was calculated using the above formula (2). FIG. 8 is an example of a graph showing the time transition of the resistance increase rate in Test Example 1. As shown in FIG. In Test Example 1, two sample batteries whose internal pressure was adjusted to negative pressure were prepared, and the test results of both sample batteries are also shown in FIG.

As shown in FIG. 8, the rate of increase in resistance of the sample battery increased over time. In addition, it was confirmed that the rate of increase in resistance per unit time of the sample battery adjusted to have a negative internal pressure was greater than that of the sample battery adjusted to have a positive internal pressure. was done.

<Test Example 2: Influence of Electrolyte Impregnation State in Electrode Body>
In Test Example 2, a sample battery was prepared so that the internal pressure was adjusted to be negative, and the state of impregnation of the electrolyte solution in the electrode assembly was different. The time transition of the rate of increase was evaluated. In this test example, a sample battery (i.e., a sample battery at the initial stage of impregnation) was adjusted so that the impregnation rate of the electrolyte into the electrode body was less than 30%, and the impregnation rate of the electrolyte into the electrode body was 30% or more. A sample battery adjusted to be less than 70% (i.e., a sample battery in the middle stage of impregnation), and a sample battery adjusted so that the impregnation rate of the electrolyte solution into the electrode assembly was 70% or more (i.e., impregnation end-of-life sample batteries) were prepared respectively. In order to adjust the impregnation state (impregnation rate) of the electrolytic solution to a desired state, the sample battery adjusted to have an SOC of 60% was allowed to stand at a temperature of 25° C. for a predetermined period of time. The impregnation rate of the electrolytic solution was obtained by ultrasonic measurement as described above. The change in resistance increase rate of these sample batteries over time was obtained in the same manner as in Test Example 1 except that these sample batteries were used. FIG. 9 is an example of a graph showing the time transition of the resistance increase rate in Test Example 2. As shown in FIG.

As shown in FIG. 9, the rate of increase in resistance of the sample battery increased over time. It was confirmed that the degree of increase in the rate of resistance increase correlates with the degree of impregnation of the electrolytic solution into the electrode body. That is, the sample battery adjusted to be in the final stage of impregnation had the largest increase in resistance increase rate over time, and the sample battery adjusted to be in the initial stage of impregnation had the greatest increase in resistance increase rate over time. confirmed to be small.

As shown in Test Example 1 above, the degree of increase in resistance increase rate per unit time of the sample battery is affected by the internal pressure. Therefore, the deterioration estimation map MP1 stored in the map information storage unit 305 may be selected based on the internal pressure of the non-aqueous electrolyte secondary battery 100 in the initial state.

The map information storage unit 305 stores the charge/discharge of the non-aqueous electrolyte secondary battery 100 based on the degradation estimation map MP1 and the deterioration state of the non-aqueous electrolyte secondary battery 100 derived based on the deterioration estimation map. A control map MP2 that determines the control values may also be stored. As an example, the control map MP2 may define the maximum input current value and/or the maximum output current value based on the temperature (Tb) and the deterioration state. In this case, the control map MP2 is preferably composed of a matrix in which the vertical axis indicates the battery temperature or SOC, and the horizontal axis indicates the amount of deterioration D of the non-aqueous electrolyte secondary battery 100 (details will be described later). , control values for charging and discharging of the non-aqueous electrolyte secondary battery 100 may be recorded.

The deterioration state estimation unit 306 is configured to refer to the deterioration estimation map MP1 stored in the map information storage unit 305 and estimate the deterioration state of the non-aqueous electrolyte secondary battery 100 . At this time, the deterioration state estimation unit 306 determines the temperature (Tb) of the non-aqueous electrolyte secondary battery 100 detected by the detection unit 310 and the SOC of the non-aqueous electrolyte secondary battery 100 obtained by the SOC acquisition unit 304. See Furthermore, the deterioration state estimation unit 306 is configured to calculate the deterioration amount D of the non-aqueous electrolyte secondary battery 100 within a predetermined period based on time information acquired by a timer (not shown).

The initial information storage unit 307 stores the initial state of the non-aqueous electrolyte secondary battery 100 . For example, it is configured to store the impregnation state of the electrolyte into the electrode body and, if necessary, the internal pressure of the non-aqueous electrolyte secondary battery 100 .

Control unit 308 cooperates with map information storage unit 305, deterioration state estimation unit 306, and initial information storage unit 307 to control charging/discharging of non-aqueous electrolyte secondary battery 100 by charging/discharging means 200. It is configured. Hereinafter, a method of controlling charge/discharge of a non-aqueous electrolyte secondary battery using the control device disclosed herein will be described with reference to FIGS. 1 and 10 as appropriate. FIG. 10 is a flow diagram illustrating a control method using the control device according to one embodiment.

As shown in FIG. 10, the control unit 308 controls the secondary battery 100 by selecting a deterioration estimation map MP1 (step S1), obtaining basic information of the non-aqueous electrolyte secondary battery 100 to be controlled, (Steps S2 and S3), estimating the deterioration state of the non-aqueous electrolyte secondary battery 100 based on the deterioration estimation map MP1 and the basic information (Step S4), and the estimated non-aqueous electrolyte It includes performing charge/discharge control based on the state of deterioration of the secondary battery 100 (step S5). In step S1, a deterioration estimation map MP1 to be referred to is selected based on the impregnation state of the electrolyte into the electrode body in the initial state of the non-aqueous electrolyte secondary battery 100. FIG. For example, the non-aqueous electrolyte secondary battery 100 to be controlled among the plurality of deterioration estimation maps MP1 based on the impregnation rate of the electrolyte into the electrode body in the initial state, which is input in advance to the initial information storage unit 307. A degradation estimation map MP1 suitable for is selected.

In step S2, the first detection unit detects the current value (Ib) flowing through the non-aqueous electrolyte secondary battery 100 within a predetermined sampling period, and the second detection unit detects the non-aqueous electrolyte secondary A voltage value (Vb) applied to the battery 100 is detected, and a third detection unit detects a temperature (Tb) of the non-aqueous electrolyte secondary battery 100 . The sampling period is not particularly limited, but can be set to several minutes to several hours, several seconds to ten and several seconds, or several milliseconds to several hundreds of milliseconds. Information sensed during the sampling period is temporarily stored in the memory of controller 300 .

In step S3, the SOC acquisition unit 304 acquires the SOC of the non-aqueous electrolyte secondary battery 100 based on the information detected in step S2. The acquired SOC information is temporarily stored in the memory of the control device 300 . In steps S2 and S3, SOC ₁ corresponding to a certain temperature (Tb ₁ ) and their duration t ₁ are acquired during the sampling period. Temperature (Tb _1,2,3,...n ), SOC _1,2,3,...n and duration t _1,2,3 depending on temperature (Tb) and/or SOC changes _{, . . . n} are acquired (n is an integer equal to or greater than 1. The same shall apply hereinafter).

In step S<b>4 , the deterioration state estimation unit 306 refers to the deterioration estimation map MP<b>1 stored in the map information storage unit 305 to estimate the deterioration state of the non-aqueous electrolyte secondary battery 100 . As an example, the deterioration state estimation unit 306 _{adds the temperature (Tb) and the period tn during which the SOC is maintained to the deterioration coefficient corresponding to the temperature (Tbn) and the SOC n obtained in} steps S2 and S3. By multiplying, the amount of deterioration _dn within the period is calculated. Then, the deterioration amount D of the non-aqueous electrolyte secondary battery 100 within the sampling period is calculated by integrating the deterioration amount _dn .

In step S5, charge/discharge control of the non-aqueous electrolyte secondary battery 100 based on the deterioration amount D is performed. As an example, the control map MP2 stored in the map information storage unit 305 is referenced to control charging/discharging of the non-aqueous electrolyte secondary battery 100 by the charging/discharging means 200 . Specifically, with reference to the control map 2, the temperature (Tb) or SOC with the longest duration within the sampling period, and the information on the calculated deterioration amount D, the non-aqueous electrolyte secondary battery 100 A charge/discharge control value can be obtained. The control unit 308 can control charging and discharging of the non-aqueous electrolyte secondary battery 100 based on the control value.

The control device disclosed herein estimates the deterioration state of a non-aqueous electrolyte secondary battery in which an electrode body in which a positive electrode sheet and a negative electrode sheet are stacked with a separator interposed therebetween and an electrolyte is housed in a battery case. It is a control device. The control device prepares a deterioration estimation map for estimating deterioration of the non-aqueous electrolyte secondary battery, which is selected based on the impregnation state of the electrolyte into the electrode body in the initial state of the non-aqueous electrolyte secondary battery. I remember. Based on this deterioration estimation map, the deterioration state of the non-aqueous electrolyte secondary battery is estimated. By using such a control device, it is possible to more accurately estimate the state of deterioration during use of a non-aqueous electrolyte secondary battery having a configuration in which an electrode assembly and an electrolyte are housed in a battery case.

Although one embodiment of the present invention has been described in detail above, this is merely an example and does not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the above-exemplified embodiments. For example, in the above embodiment, a plurality of deterioration estimation maps are stored in the map information storage unit, and are used so as to correspond to the impregnation state of the electrolyte into the electrode body of the non-aqueous electrolyte secondary battery in the initial state. Although this is a configuration for selecting a degradation estimation map, it is not limited to this. A deterioration estimation map that serves as a reference may be stored in the map information storage unit, and may be appropriately corrected so as to correspond to the impregnation state of the electrolyte into the electrode body of the non-aqueous electrolyte secondary battery in the initial state. For example, the map information storage unit can store a correction map for correcting the reference degradation estimation map. Correction coefficients (degradation coefficient correction) may be described in the correction map. For example, a correction coefficient can be calculated for each temperature and SOC in the deterioration coefficient map and recorded in the correction map. Here, the correction coefficient is, for example, the following formula (3):
Correction coefficient = deterioration slope (negative pressure) / deterioration slope (positive pressure) (3)
can be obtained based on The deterioration slope (negative pressure) is expressed by the following formula (4):
Degradation slope (negative pressure) = (R1 (negative pressure) / R0 (negative pressure) - 1) / √T (when measuring R1) (4)
can be obtained based on The deterioration slope (positive pressure) is given by the following equation (5):
Degradation slope (positive pressure) = (R1 (positive pressure) / R0 (positive pressure) - 1) / √T (when measuring R1) (5)
can be obtained based on

Further, for example, the maximum allowable deterioration amount _Dmax is determined in advance, and when the deterioration amount D calculated as described above becomes equal to or greater than the maximum deterioration amount _Dmax , charge/discharge control is performed. may In this case, the maximum deterioration amount _Dmax is stored in advance in the memory of the control device, and when the deterioration amount D reaches or exceeds the maximum deterioration amount _Dmax , charging of the non-aqueous electrolyte secondary battery to be controlled is performed. Reference may be made to a control map configured to obtain control values for the discharge. An example of such a control map is a control map MP3 in which the maximum deterioration amount _Dmax is recorded on the horizontal axis of the control map MP2 of the above embodiment. The control method using the control map MP3 is the same as the control method using the control map MP2 in the above embodiment, except that it is referred to when the amount of deterioration D reaches or exceeds the maximum amount of deterioration _Dmax . be. If the amount of deterioration D is less than the maximum amount of deterioration _Dmax , the charge/discharge of the non-aqueous electrolyte secondary battery is not controlled, and the process returns to step S2 in FIG.

1 secondary battery system 100 non-aqueous electrolyte secondary battery 200 charging/discharging means 300 control device 301 first detection unit 302 second detection unit 303 third detection unit 304 SOC acquisition unit 305 map information storage unit 306 deterioration state estimation unit 307 Initial information storage unit 308 Control unit

Claims (7)

A control device for estimating the deterioration state of a non-aqueous electrolyte secondary battery in which an electrode body in which a positive electrode sheet and a negative electrode sheet are stacked with a separator interposed therebetween and an electrolyte is housed in a battery case,
storing a deterioration estimation map for estimating deterioration of the non-aqueous electrolyte secondary battery, which is selected based on the state of impregnation of the electrolyte into the electrode assembly in the initial state of the non-aqueous electrolyte secondary battery; and
A control device configured to estimate a deterioration state of the non-aqueous electrolyte secondary battery based on the deterioration estimation map. 2. The control device according to claim 1, wherein the deterioration estimation map records the relationship between the temperature, the SOC, and the deterioration coefficient of the non-aqueous electrolyte secondary battery. further storing a control map for determining control values for charging and discharging the non-aqueous electrolyte secondary battery based on the deterioration state of the non-aqueous electrolyte secondary battery derived based on the deterioration estimation map;
3. The control device according to claim 1, configured to control charging and discharging of said non-aqueous electrolyte secondary battery based on said deterioration state estimated based on said deterioration estimation map and said control map. . The control device is
A plurality of deterioration estimation maps are stored in advance,
Based on the state of impregnation of the electrolyte into the electrode body in the initial state of the non-aqueous electrolyte secondary battery to be controlled, the non-aqueous electrolyte secondary to be controlled is selected from the plurality of deterioration estimation maps. 4. The control device according to any one of claims 1 to 3, wherein the deterioration estimation map suitable for a battery is selected. The control device is
a reference deterioration estimation map;
A plurality of correction maps for correcting the reference deterioration estimation map are stored in advance,
for correcting the reference deterioration estimation map among the plurality of correction maps based on the state of impregnation of the electrolyte into the electrode body in the initial state of the non-aqueous electrolyte secondary battery to be controlled; 4. A control device as claimed in any preceding claim, arranged to select a correction map. The control device according to any one of claims 1 to 5, wherein the deterioration estimation map is further selected based on the internal pressure of the non-aqueous electrolyte secondary battery in the initial state. An electrode body in which a positive electrode sheet including a positive electrode active material layer and a negative electrode sheet including a negative electrode active material layer are stacked with a separator interposed therebetween; an electrolyte; and a battery case accommodating the electrode body and the electrolyte. non-aqueous electrolyte secondary battery,
charging and discharging means for charging and discharging the non-aqueous electrolyte secondary battery; and
A control device according to any one of claims 1 to 6,
A secondary battery system.

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