WO2017098686A1 - Battery pack, electricity storage device and deterioration detecting method - Google Patents

Abstract

This battery pack is provided with: a capacity variation amount calculating unit which accepts as inputs a full charge capacity or a capacity retention ratio of a secondary battery, and an elapsed time, and calculates an amount of variation in the full charge capacity or the capacity retention ratio; and a rapid deterioration assessing unit which assesses deterioration on the basis of a threshold assessment of the amount of variation calculated by the capacity variation amount calculating unit.

Description

Battery pack, power storage device, and deterioration detection method

This technology relates to, for example, a battery pack using a lithium ion secondary battery, a power storage device, and a secondary battery deterioration detection method.

Secondary batteries such as lithium ion batteries and nickel metal hydride batteries are widely used in mobile terminals such as mobile phones as power sources. In recent years, with the increase in environmental protection, renewable energy such as solar power generation and wind power generation has attracted attention, and secondary batteries have been attracting attention and spreading as applications for storing the energy. As for automobiles, hybrid cars and electric cars equipped with secondary batteries are becoming popular. In this way, the secondary battery plays a role as a key device indispensable for power supply applications.

¡Secondary batteries deteriorate even when not in use, and the degree of deterioration varies depending on the usage conditions. Therefore, deterioration estimation (SOH (State Of Health)) is indispensable in order to estimate SOC (State Of Charge: battery charging rate) with high accuracy. In addition, grasping the deterioration state of the secondary battery is important for ensuring safety such as life judgment. From the standpoint of using a secondary battery, typical capacity degradation includes battery capacity degradation and output voltage degradation. Here, the battery capacity means a full charge capacity. The capacity maintenance rate is expressed by a numerical value obtained by dividing the current full charge capacity by the initial full charge capacity as a deterioration index. When calculating the capacity maintenance rate, the discharge capacity from the fully charged position to the voltage lower limit is often used instead of the fully charged capacity.

It is empirically known that the capacity deterioration of the secondary battery is approximately linearly proportional to the square root over time. In general, such an empirical route law is often applied to predict deterioration of a secondary battery. In many cases, the life expectancy of secondary batteries is discussed by formulating deterioration prediction formulas along with the results of deterioration tests in accordance with the root law. However, in many cases, even if it follows the deterioration prediction formula, it cannot cope with unexpected behavior that does not follow the root rule.

For example, a sudden deterioration phenomenon of battery capacity at the end of the life is known as an unexpected behavior that does not follow the route rule. In addition, rapid deterioration of battery capacity has been confirmed due to charging / discharging at a low temperature and charging / discharging at a high rate (high input, high output). Since it deteriorates at a rapid rate compared with the deterioration prediction formula, it is necessary to accurately capture such unexpected behavior in order to ensure the safety of the system using the secondary battery. For the sake of convenience, deterioration at a rapid speed will be referred to as rapid deterioration.

In order to detect an abnormal individual in the inspection at the time of secondary battery manufacture, the difference between the initial performance measurement amount and the current performance measurement amount (performance deterioration amount) is obtained. A method of diagnosing that deterioration has occurred and diagnosing an abnormality has been proposed (see Patent Document 1). The thing of patent document 1 is described that abnormality diagnosis can be performed with high accuracy even when the performance varies depending on the production time, production line, etc. of the storage battery.

Japanese Patent Laid-Open No. 2015-59933

In the case of the one described in Patent Document 1, it is necessary to accurately determine the amount of performance deterioration. Although it may be possible to accurately measure the battery capacity on the production line, it is difficult to accurately measure or calculate the battery capacity with an in-vehicle battery such as an electric vehicle or a storage battery linked with a system such as photovoltaic power generation. For this reason, even if this method is applied to an in-vehicle battery or a power storage system as it is to detect rapid deterioration, there is a risk that many false detections occur.

Further, as shown in FIG. 18, since the actual deterioration history curve (broken line) changes depending on the use conditions such as current and environmental temperature, it is difficult to maintain high accuracy of the deterioration prediction formula (solid line) under the actual use conditions. is there. For this reason, if the accuracy of the deterioration prediction formula is not high, determining the threshold value of the difference between the deterioration prediction formula and the measured value may cause an erroneous determination.

The present technology has been made in view of such conventional problems, and includes a battery pack, a power storage device, and a deterioration in which sudden deterioration that is unexpected behavior is simply and accurately estimated from a history of battery capacity. An object is to provide a detection method.

In order to solve the above-described problem, the present technology provides a capacity change amount calculation unit that calculates the change amount of the full charge capacity or the capacity maintenance rate by inputting the full charge capacity or the capacity maintenance rate of the secondary battery and the elapsed time. When,
A battery pack comprising: a rapid deterioration determination unit that determines deterioration based on a threshold determination based on a change amount calculated by a capacity change amount calculation unit.
The present technology is a power storage device that includes the above-described battery pack and supplies power to an electronic device connected to the battery pack.
This technology calculates the amount of change in the full charge capacity or capacity maintenance rate from the full charge capacity or capacity maintenance rate of the secondary battery and the elapsed time,
This is a method for detecting deterioration of a secondary battery, in which deterioration is detected based on a threshold value determination based on a calculated change amount.

According to at least one embodiment, since the rapid deterioration is detected by determining the threshold value of the full charge capacity or the capacity maintenance ratio change amount calculated by the linear regression analyzer, the noise deterioration is strong, and the rapid deterioration is simply detected. can do. Note that the effects described here are not necessarily limited, and may be any of the effects described in the present technology.

It is a graph used for description of capacity rapid deterioration. It is a graph used for description of the rapid degradation detection method by this technique. It is a graph used for description of the precision of rapid deterioration determination. It is a graph used for description of the precision of rapid deterioration determination. It is a block diagram of an example of the rapid deterioration detection apparatus. It is a block diagram of an example of a rapid deterioration notification device. It is a flowchart of an example of the rapid deterioration detection method. It is a graph for description of a method for increasing the accuracy of rapid deterioration detection. It is a block diagram of the other example of the rapid deterioration notification device. It is a flowchart of the other example of the rapid degradation notification method. It is a basic diagram used for description of the deteriorated OCV curve. It is a basic diagram used for description of the process which estimates the other OCV curve from one OCV curve. It is a flowchart which shows the flow of a process of OCV curve calculation. It is an approximate line figure used for explanation of processing of calculation of an OCV plot by linear interpolation. It is a block diagram of an example of a battery pack to which the present technology is applied. It is a block diagram of an example of a power storage device to which the present technology is applied. It is a block diagram of an example of an electrical storage system to which this art is applicable. It is a graph for description of sudden deterioration detection.

<1. Embodiment of the present technology>
Hereinafter, embodiments of the present technology will be described. The embodiments described below are preferred specific examples of the present technology, and various technically preferable limitations are given. However, the scope of the present technology is not limited to the present technology in the following description. Unless otherwise specified, the present invention is not limited to these embodiments.

"Method for detecting rapid deterioration using this technology"
The present technology is characterized by simply and accurately estimating sudden deterioration that deviates from the deterioration prediction and becomes unexpected behavior based on a history of battery capacity (full charge capacity). FIG. 1 is an explanatory diagram of sudden capacity deterioration. The horizontal axis represents time (unit: year), and the vertical axis represents capacity retention rate. The capacity maintenance rate is the ratio of the current capacity to the initial capacity. For example, at the end of the lifetime, the battery capacity may rapidly deteriorate against the deterioration prediction formula (indicated by a broken line). Since it deteriorates at a rapid rate compared with the deterioration prediction formula, it is necessary to accurately capture such rapid deterioration in order to ensure the safety of the system using the secondary battery.

Battery capacity can be obtained by measuring the discharge capacity up to the end-of-discharge voltage in accordance with the specified conditions (current value, temperature, etc.) starting from full charge. However, in actual systems on the market, it is actually impossible to assume an environment in which accurate measurement is performed, such as at the time of experiment or manufacturing. Even if an accurate measurement environment is provided, special measures such as disconnecting the system are required for measuring battery capacity, and the frequency of measurement is limited, such as during system maintenance. In a storage battery linked with a system such as photovoltaic power generation, it is difficult to fix the current value due to load fluctuation due to factors such as sunlight conditions. In addition, there may be extremely few opportunities for full charge, which is important when measuring battery capacity.

Therefore, in such a case, the battery capacity is estimated by calculation. There are various battery capacity calculation methods. For example, the battery capacity can be estimated from the correlation between the estimated open circuit voltage (OCV) and charge / discharge capacity (Q). Due to estimation by calculation, there is an error compared with measurement. For this reason, a method that is highly resistant to errors is required when estimating rapid deterioration.

In this technology, the battery capacity and time of the secondary battery are input, the amount of change in the battery capacity is calculated by linear regression analysis, and the rapid deterioration is determined based on the threshold value determination using the calculated amount of change.

Further, the present technology will be described with reference to FIG. In FIG. 2, the horizontal axis represents elapsed time, for example, the unit of year, and the vertical axis represents the capacity maintenance rate. The plot in FIG. 2 is an estimated value of the capacity maintenance rate. That is, an estimated value of the capacity maintenance ratio is obtained by dividing the full charge capacity obtained by calculation by the initial capacity. The full charge capacity can be obtained by calculation using voltage, current, and temperature data of the secondary battery.

A linear regression analysis is performed on the history of the capacity maintenance rate in a predetermined section, and the amount of change in the capacity maintenance rate (or battery capacity) is calculated from the slope of the straight line obtained as a result of the linear regression analysis. This amount of change is compared with a threshold value, and when the amount of change is larger than the threshold value, it is determined that rapid deterioration has occurred. Conversely, if the change amount is smaller than the threshold value, it is determined that no rapid deterioration has occurred. In the example of FIG. 2, it is determined that rapid deterioration has not occurred when the amount of change is a straight line A1 that is smaller than the threshold, and sudden deterioration has occurred when the amount of change is a straight line A2 that is larger than the threshold. It is determined.

Sudden deterioration has been confirmed at the end of life, charging / discharging at low temperature, charging / discharging at high rate (high input, high output), etc. Based on the history of battery capacity in these events, a threshold for rapid deterioration is determined in advance. This threshold value may be changed according to use conditions and changes with time, such as current, temperature, and elapsed time. Furthermore, a threshold value may be set according to the type of secondary battery.

The noise immunity of the present technology will be described with reference to FIGS. FIG. 3A is a graph of an example of a change curve of the capacity retention rate when there is no noise. FIG. 3B is a graph showing a result of obtaining the amount of change in the capacity maintenance rate by the difference calculation method. As a method for calculating the amount of change, it can be simply calculated by the difference between battery capacity history points. Assuming that the capacity maintenance rate at a certain time T (k) is R (k), the capacity maintenance rate per unit time (for example, year) from the capacity maintenance rate R (k-1) at the previous history time T (k-1). The change amount ΔR (k) can be calculated from the following equation. This calculation method is a difference calculation method.

ΔR (k) = (R (k) −R (k−1)) / (T (k) −T (k−1))

FIG. 3C is a graph showing the result of determining the amount of change in the capacity maintenance rate according to the present technology. In both of the difference calculation method and the present technology, the amount of change becomes a large value after the elapsed time (for example, 4 years) at which rapid deterioration occurs. Therefore, rapid degradation can be detected by either method.

FIG. 4A is a graph of an example of a change curve of the capacity maintenance ratio when there is noise. For example, Gaussian noise with an amplitude of ± 5% is added to the capacity retention rate data of FIG. 3A. FIG. 4B is a graph showing the result of obtaining the amount of change in the capacity maintenance rate by the difference calculation method. FIG. 4C is a graph showing a result of obtaining the amount of change in the capacity retention rate according to the present technology.

The graph of the amount of change obtained by the difference calculation method (FIG. 4B) is significantly affected by the influence of noise, and the accuracy of calculating the amount of change in the capacity maintenance rate is significantly deteriorated. On the other hand, in the graph of the amount of change obtained by the present technology (FIG. 4C), the amount of change becomes a large value after the elapsed time (for example, 4 years) at which rapid deterioration occurs. Therefore, compared with the reference technique, it is possible to determine rapid deterioration using the change amount as an index without being affected by noise. It can be seen that the linear regression analysis method is highly resistant to battery capacity errors.

In the present technology, a capacity maintenance rate change amount ΔR (k) per unit time (for example, year) is calculated from a linear regression analysis with respect to a battery capacity history point. The linear regression analysis will be described.
The linear regression model is given by

Where y is a dependent variable, xk is an independent variable, and ε is an error. When k is 3 or more, it is called a linear multiple regression model. The linear regression analysis by the least square method is a method for obtaining each coefficient so that the sum of squares of a residual (difference between an estimated value and a measured value) is minimized. Specifically, a simultaneous equation with “= 0” as an equation obtained by partial differentiation of the residual sum of squares by each coefficient is established and solved.

Thus, the slope a and intercept b of the straight line can be calculated from the measured values by linear regression analysis. By giving the battery capacity history value to Equation 10 with the Y axis as the capacity maintenance rate and the X axis as the time, the slope of the straight line by the linear regression analysis, that is, the capacity maintenance rate change amount ΔR (k) can be calculated. As shown in FIG. 4, the capacity maintenance rate change amount by the linear regression analysis is strong in noise resistance, and rapid deterioration can be determined. This calculation method is called a linear regression analysis method. To perform linear regression analysis, at least three points of data are required. The required number of data points can be arbitrarily determined (for example, 5 points).

"Example of sudden deterioration detector"
FIG. 5 shows an example of the rapid deterioration detection apparatus. The battery capacity calculator 2 receives the information on the current, voltage, and temperature from the secondary battery 1 having a configuration in which a single battery cell or a plurality of battery cells are connected in series and / or in parallel, and the battery capacity calculator 2 calculates the battery capacity (full charge capacity). calculate. The secondary battery 1 constitutes a battery pack. The capacity maintenance rate is calculated by the maintenance rate calculator 3. The initial battery capacity of the secondary battery 1 is stored in the initial capacity memory 4. The maintenance ratio calculator 3 calculates the ratio between the initial capacity and the current battery capacity (capacity maintenance ratio).

The capacity maintenance ratio obtained by the maintenance ratio calculator 3 is stored in the maintenance ratio storage 5. In this case, the capacity maintenance rate is stored in the maintenance rate storage device 5 in association with the elapsed time. The linear regression analyzer 6 obtains the amount of change in the capacity maintenance ratio by the above-described linear regression analysis method using, for example, five samples of the capacity maintenance ratio data stored in the maintenance ratio storage 5.

The amount of change obtained by the linear regression analyzer 6 is supplied to the rapid deterioration determiner 7 and compared with a threshold value. When the amount of change is equal to or greater than the threshold value, it is determined that the deterioration is rapid. The determination result of the rapid deterioration determiner 7 is supplied to the rapid deterioration notifier 8 to notify the user whether or not the rapid deterioration has occurred. The rapid deterioration notification device 8 performs visual notification, acoustic notification, and the like. FIG. 6 is a specific example of the rapid deterioration notifier 8 that visually notifies the display device 8a.

"Example of rapid deterioration detection method"
The function of the rapid deterioration detection device shown in FIG. 5 can be recorded as a program on a recording medium. Therefore, the function of the rapid deterioration detection device can be realized by reading this recording medium with a computer and executing it with an MPU (Micro Processing Unit), DSP (Digital Signal Processor) or the like. An example of the rapid deterioration detection method described below with reference to FIG. 7 can be realized as a program executed by the information processing apparatus.

Step ST1: Record the capacity maintenance rate in the maintenance rate memory. The capacity maintenance rate is obtained by a maintenance rate calculator as in the above-described rapid deterioration detection device.
Step ST2: It is determined whether or not the capacity maintenance rate is equal to or greater than the necessary number of points (necessary samples).
Step ST3: If the determination result in step ST2 is negative, it is determined that “abrupt deterioration occurrence cannot be detected” and the process ends.

Step ST4: If the determination result in step ST2 is affirmative, linear regression analysis is executed.
Step ST5: It is determined whether or not the amount of change in the capacity maintenance rate obtained by the linear regression analysis method satisfies the threshold condition.
Step ST6: When the threshold condition is satisfied, that is, when the amount of change is equal to or greater than the threshold, it is determined that “abrupt deterioration has occurred”. Then, the process ends.
Step ST7: When the threshold condition is not satisfied, that is, when the amount of change is smaller than the threshold, it is determined that “no rapid deterioration occurs”. Then, the process ends.

"Other examples of rapid deterioration detection equipment"
Next, another example of the rapid deterioration detection device will be described. As shown in FIG. 8, since the capacity retention rate change amount after the inflection point of the rapid deterioration becomes large, as described above, the rapid deterioration can be determined from the comparison between the change amount and a predetermined threshold value. However, even at the initial stage of deterioration, the deterioration rate is fast as is empirically known from the root law. Therefore, there is a risk that the initial stage of deterioration is erroneously determined as rapid deterioration. Since sudden deterioration is an event that occurs when deterioration progresses, such as at the end of the life, detection accuracy of rapid deterioration is improved by setting a threshold value for the capacity maintenance rate and determining the threshold value. For example, the threshold value is set to 80%, and only the estimated battery capacity that is below the threshold value is determined as a target for rapid deterioration. As a result, it is possible to prevent erroneous determination of the initial stage of deterioration as rapid deterioration.

Since sudden deterioration is an unexpected behavior, it cannot be captured by the deterioration prediction formula. Therefore, the detection accuracy of the rapid deterioration is improved by determining the threshold value of the difference absolute value D between the calculated value based on the deterioration prediction formula and the calculated value based on the battery capacity estimation method for the capacity maintenance rate. For example, the threshold value is set to 10%, and only when the absolute value of the capacity maintenance rate difference is equal to or larger than the threshold value, the determination target of rapid deterioration is made.

Therefore, in order to increase the accuracy of determination (detection), three conditions of (1) capacity maintenance rate change amount, (2) capacity maintenance rate, and (3) absolute difference value D are used as conditions for rapid deterioration determination. . When all of these are satisfied, it is determined that the deterioration is rapid. However, when (1) and (2) or (1) and (3) are satisfied, it may be determined that the deterioration is rapid.

Another example is a case in which rapid deterioration is determined when the conditions (1), (2), and (3) are satisfied. FIG. 9 shows another example of the rapid deterioration detection device. Similarly to the above-described example, the capacity maintenance rate is calculated by the maintenance rate calculator, and the obtained capacity maintenance rate is stored in the maintenance rate storage unit 15. In this case, the capacity maintenance rate is stored in the maintenance rate storage unit 15 in association with the elapsed time. The linear regression analyzer 18 determines the amount of change in the capacity maintenance rate by the above-described linear regression analysis method using, for example, five samples of the capacity maintenance rate data stored in the maintenance rate storage unit 15. The amount of change obtained by the linear regression analyzer 18 is supplied to the rapid deterioration determiner 19 and compared with a threshold value.

The capacity maintenance rate is supplied to the maintenance rate threshold determination unit 16. The threshold value is 80%, for example. A determination result as to whether or not the capacity maintenance rate is equal to or higher than the threshold value is supplied to the rapid deterioration determination unit 19. This determination result corresponds to the condition (2).

The same numerical value as the capacity maintenance rate stored in the maintenance rate memory 15 and the capacity maintenance rate predicted by the deterioration prediction formula are supplied to the maintenance rate difference determiner 17 together with information over time. The maintenance rate difference determiner 17 determines a threshold value for the difference absolute value D between the capacity maintenance rate based on the deterioration prediction formula and the calculated value of the battery capacity. The determination result as to whether or not the absolute difference value D is equal to or greater than the threshold value is supplied to the rapid deterioration determiner 19. This determination result corresponds to the condition (3).

The rapid deterioration determiner 19 determines whether or not the amount of change obtained by the linear regression analyzer 18 is equal to or greater than a threshold value. This determination result corresponds to the condition (1). When the change amount is equal to or greater than the threshold, the maintenance rate is equal to or greater than the threshold, and the difference absolute value D is equal to or greater than the threshold, it is determined that rapid deterioration has occurred. The determination result of the rapid deterioration determiner 19 is supplied to the rapid deterioration notifier 20 to notify the user whether or not the rapid deterioration has occurred. The rapid deterioration notification device 20 performs visual notification, acoustic notification, and the like.

"Other examples of rapid deterioration detection method"
The function of the rapid deterioration detection apparatus shown in FIG. 9 can be recorded as a program on a recording medium, and the function of the rapid deterioration detection apparatus is realized by reading the recording medium with a computer and executing it with an MPU, DSP, or the like. Can do. Another example of the rapid deterioration detection method described below with reference to FIG. 10 can be realized as a program executed by the information processing apparatus.

Step ST11: Record the capacity maintenance rate in the maintenance rate memory. The capacity maintenance rate is obtained by a maintenance rate calculator as in the above-described rapid deterioration detection device.
Step ST12: It is determined whether or not the capacity maintenance rate is equal to or greater than the necessary number (necessary samples).
Step ST13: If the determination result in step ST2 is negative, it is determined that “abrupt deterioration occurrence cannot be detected” and the process ends.

Step ST14: When the determination result of step ST2 is affirmative, linear regression analysis is executed.
Step ST15: It is determined whether or not the amount of change in the capacity maintenance rate obtained by the linear regression analysis method satisfies the threshold condition.
Step ST16: When the threshold condition is not satisfied, that is, when the amount of change is smaller than the threshold, it is determined that “no rapid deterioration occurs”. Then, the process ends.

Step ST17: If the threshold condition is satisfied in step ST15, that is, if the change amount is greater than or equal to the threshold, it is determined whether or not the capacity maintenance rate satisfies the threshold condition. When the threshold condition is not satisfied, that is, when the capacity maintenance rate is larger than the threshold (initial state), it is determined that “no rapid deterioration occurs” (step ST16). Then, the process ends.
Step ST18: When the threshold condition is satisfied in step ST17, that is, when the capacity maintenance rate is smaller than the threshold, whether or not the absolute value D of the difference between the capacity maintenance rate and the predicted value based on the deterioration prediction formula satisfies the threshold condition. Is determined. When the threshold condition is not satisfied, that is, when the difference absolute value D is smaller than the threshold, it is determined that “no rapid deterioration occurs” (step ST16). Then, the process ends.
Step ST19: If the threshold condition is satisfied in step ST18, that is, if the difference absolute value D between the capacity maintenance rate and the predicted value based on the deterioration prediction formula is larger than the threshold, it is determined that “abrupt deterioration has occurred”. Then, the process ends.

In the other examples described above, it is determined that “abrupt deterioration has occurred” when the three conditions (1), (2), and (3) are satisfied, so that the determination accuracy can be increased.

The present technology described above has high noise resistance, and since it is mainly a calculation based on linear regression analysis, it is possible to detect sudden deterioration in a simple manner. In the present technology, it is possible to detect a danger at an early stage before reaching the lifetime by detecting a sudden deterioration that is an unexpected behavior. Therefore, it becomes possible to improve the safety of the system using the storage battery. At an early stage before reaching the end of its service life, measures to ensure safety (system shutdown, battery replacement, etc.) can be made.

An example of a method for calculating the full charge capacity in the above-described technology will be described below. FIG. 11 is an explanatory diagram of a deteriorated OCV curve. When the OCV curve deteriorates, it becomes a contracted / shifted shape. It is known that the OCV curve of a battery can be expressed by the difference between the OCV curves of a single positive electrode and a single negative electrode (generally measured using Li metal as a counter electrode). An OCV curve of the battery can be generated by taking a difference by expanding and contracting each of the unipolar OCV curves acquired in advance. The battery capacity can be estimated from the discharge capacity (CAPnow) until the OCV curve of the battery reaches the cutoff voltage.

As shown in FIG. 12, the discharge capacity and OCV estimated value recorded in the memory or the like can be plotted with the discharge capacity Q as the horizontal axis and the voltage as the vertical axis. An optimal fitting condition is obtained by fitting the OCV curve of the generated battery while expanding / contracting / shifting the unipolar OCV curve acquired in advance with respect to the OCV value locus.

FIG. 13 shows a flowchart of OCV curve calculation. Here, as an example, a method for generating an OCV curve of a battery by expanding and contracting and shifting a unipolar OCV curve will be described. First, the amount of expansion / contraction / shift with respect to the unipolar OCV curve is used as a parameter, and a range of values for changing the parameter is set. For example, in the case of the expansion / contraction magnification, it is changed at intervals of 0.05 from 0.5 to 1.0. Under such a parameter range, fitting to the OCV value trajectory is performed while changing a parameter for generating an OCV curve (a parameter of OCV curve configuration information), and an OCV curve as an optimum condition is calculated.

The process of generating the other OCV curve from the configuration information of one OCV curve will be described in more detail with reference to the flowchart of FIG. Note that the method of calculating the OCV curve is not limited to the method described here. Here, as an example, a method for generating an OCV curve of a battery by expanding and contracting and shifting a single pole OCV curve will be described.

Step ST21: First, the expansion / contraction magnification (Xp, Xn) and the shift amount (Yp, Yn) with respect to the unipolar OCV curve are used as parameters, and a range of values for changing the parameters is set. For example, in the case of expansion / contraction magnification (Xp, Xn), it is changed from 0.5 to 1.0 at 0.05 intervals.
Step ST22: The parameter of the OCV curve configuration information is set within the set range.
Step ST23: Generate positive and negative OCV curves corresponding to the set parameters.
Step ST24: An OCV curve of the battery is generated from the difference between the positive and negative OCV curves.

Step ST25: Calculate the root mean square (referred to as RMS) of the OCV value trajectory and the OCV curve.
Step ST26: The calculated RMS calculated value is compared with the minimum value (RMS minimum value) among the previously calculated RMS calculated values. If the RMS calculation value is equal to or greater than the RMS minimum value, the process returns to step ST12 (setting of parameters (Xp, Yp, Xn, Yn) of OCV curve configuration information).
Step ST27: If the determination result in step ST26 is affirmative, that is, if (RMS calculation value <RMS minimum value), the RMS minimum value and OCV curve configuration information (Xp, Yp, Xn, Yn) are updated and recorded.
Step ST28: It is determined whether or not the entire parameter range is covered. If it is determined that they are not covered, the process returns to step ST22, and the processes of steps ST22 to ST27 described above are performed.
Step ST29: Generate OCV curves for the positive electrode and the negative electrode with the OCV curve configuration information that minimizes RMS.
Step ST30: An OCV curve of the battery is generated from the difference between the positive and negative OCV curves.
The OCV curve that is the optimum condition is calculated by the above processing.

Generate OCV curves for positive and negative electrodes. An example of generating an OCV curve of the positive electrode will be described. For the positive OCV curve acquired in advance, the discharge capacity at a certain point is defined as Qp0 (k). Assuming that the expansion / contraction magnification is Xp and the shift amount (the direction in which the discharge capacity decreases) is Yp, the discharge capacity Qp (k) at this point can be expressed by the following equation.

こ の By changing the point position of the discharge capacity in this way, the shape of the OCV curve is manipulated to generate the OCV curve of the positive electrode. Similarly, the negative electrode OCV curve can be expressed by the following equation.

In order to calculate the OCV curve of the battery, it is necessary to align the Q positions of the positive electrode and the negative electrode before calculating the difference between the positive and negative OCV curves. FIG. 14 shows an example of calculating the OCV plot by linear interpolation. Assuming that the expansion / contraction magnification is 0.9 and the shift amount is 100 [mAh], the points of 510 [mAh] and 520 [mAh] move to the points of 359 [mAh] and 368 [mAh], respectively. When it is determined that the Q interval is 10 [mAh], an OCV value corresponding to 360 [mAh] is generated by a method such as linear interpolation.

The battery OCV curve is generated from the difference between the positive and negative OCV curves. The OCV values of the positive electrode and the negative electrode at a certain discharge capacity Q (k) are OCVp (k) and OCVn (k), respectively. The OCV (k) that is the OCV value of the battery at the discharge capacity Q (k) can be expressed as the following equation.

For calculation, the root mean square (RMS) of the OCV value trajectory and the generated OCV curve is calculated. RMS can be expressed as: A point on the OCV value locus is defined as OCVe (k). N is the number of plot points constituting the OCV curve. The parameter (magnification, shift) that minimizes the RMS value is recorded.

Optimized OCV curve can be calculated by obtaining the parameter that minimizes the RMS value.

<2. Application example>
"Battery pack"
FIG. 15 is a block diagram illustrating a circuit configuration example when the present technology is applied to a battery pack. The battery pack includes a switch unit 304 including an assembled battery 301, an exterior, a charge control switch 302a, and a discharge control switch 303a, a current detection resistor 307, a temperature detection element 308, and a control unit 310.

The battery pack also includes a positive electrode terminal 321 and a negative electrode lead 322. During charging, the positive electrode terminal 321 and the negative electrode lead 322 are connected to the positive electrode terminal and the negative electrode terminal of the charger, respectively, and charging is performed. Further, when the electronic device is used, the positive electrode terminal 321 and the negative electrode lead 322 are connected to the positive electrode terminal and the negative electrode terminal of the electronic device, respectively, and discharging is performed.

The assembled battery 301 is formed by connecting a plurality of secondary batteries 301a in series and / or in parallel. The secondary battery 301a is a secondary battery of the present technology. In addition, in FIG. 15, the case where the six secondary batteries 301a are connected in 2 parallel 3 series (2P3S) is shown as an example, but it is like n parallel m series (n and m are integers). Any connection method may be used.

The switch unit 304 includes a charge control switch 302a and a diode 302b, and a discharge control switch 303a and a diode 303b, and is controlled by the control unit 310. The diode 302b has a reverse polarity with respect to the charging current flowing from the positive electrode terminal 321 in the direction of the assembled battery 301 and the forward polarity with respect to the discharging current flowing from the negative electrode lead 322 in the direction of the assembled battery 301. The diode 303b has a forward polarity with respect to the charging current and a reverse polarity with respect to the discharging current. In the example, the switch unit 304 is provided on the + side, but may be provided on the-side.

The charge control switch 302a is turned off when the battery voltage becomes the overcharge detection voltage, and is controlled by the charge / discharge control unit so that the charge current does not flow in the current path of the assembled battery 301. After the charging control switch 302a is turned off, only discharging is possible via the diode 302b. Further, it is turned off when a large current flows during charging, and is controlled by the control unit 310 so that the charging current flowing in the current path of the assembled battery 301 is cut off.

The discharge control switch 303 a is turned off when the battery voltage becomes the overdischarge detection voltage, and is controlled by the control unit 310 so that the discharge current does not flow in the current path of the assembled battery 301. After the discharge control switch 303a is turned off, only charging is possible via the diode 303b. Further, it is turned off when a large current flows during discharging, and is controlled by the control unit 310 so as to cut off the discharging current flowing in the current path of the assembled battery 301.

The temperature detection element 308 is, for example, a thermistor, is provided in the vicinity of the assembled battery 301, measures the temperature of the assembled battery 301, and supplies the measured temperature to the control unit 310. The voltage detection unit 311 measures the voltage of the assembled battery 301 and each secondary battery 301a constituting the assembled battery 301, A / D converts this measurement voltage, and supplies the voltage to the control unit 310. The current measurement unit 313 measures the current using the current detection resistor 307 and supplies this measurement current to the control unit 310.

The switch control unit 314 controls the charge control switch 302a and the discharge control switch 303a of the switch unit 304 based on the voltage and current input from the voltage detection unit 311 and the current measurement unit 313. The switch control unit 314 sends a control signal to the switch unit 304 when any voltage of the secondary battery 301a falls below the overcharge detection voltage or overdischarge detection voltage, or when a large current flows suddenly. By sending, overcharge, overdischarge, and overcurrent charge / discharge are prevented.

Here, for example, when the secondary battery is a lithium ion secondary battery, the overcharge detection voltage is determined to be 4.20 V ± 0.05 V, for example, and the overdischarge detection voltage is determined to be 2.4 V ± 0.1 V, for example. .

As the charge / discharge switch, for example, a semiconductor switch such as a MOSFET can be used. In this case, the parasitic diode of the MOSFET functions as the diodes 302b and 303b. When a P-channel FET is used as the charge / discharge switch, the switch control unit 314 supplies control signals DO and CO to the gates of the charge control switch 302a and the discharge control switch 303a, respectively. When the charge control switch 302a and the discharge control switch 303a are P-channel type, they are turned on by a gate potential that is lower than the source potential by a predetermined value or more. That is, in normal charging and discharging operations, the control signals CO and DO are set to a low level, and the charging control switch 302a and the discharging control switch 303a are turned on.

For example, in the case of overcharge or overdischarge, the control signals CO and DO are set to the high level, and the charge control switch 302a and the discharge control switch 303a are turned off.

The memory 317 includes a RAM and a ROM, and includes, for example, an EPROM (Erasable Programmable Read Only Memory) that is a nonvolatile memory. In the memory 317, the numerical value calculated by the control unit 310, the internal resistance value of the battery in the initial state of each secondary battery 301a measured in the manufacturing process, and the like are stored in advance, and can be appropriately rewritten. . Further, by storing the full charge capacity of the secondary battery 301a, for example, the remaining capacity can be calculated together with the control unit 310.

The temperature detection unit 318 measures the temperature using the temperature detection element 308, performs charge / discharge control at the time of abnormal heat generation, and performs correction in the calculation of the remaining capacity.

The function of the rapid deterioration detection device described above is included in the control unit 310. The function of the rapid deterioration notifier is provided inside the battery pack or outside the battery pack. The rapid deterioration detection device detects the deterioration of the assembled battery 301.

"Power storage system"
A power storage system according to the first embodiment of the present technology will be described. FIG. 16 illustrates an example of a configuration of a power storage system. The power storage system 81 includes a power storage module 82 and a controller 83. Electric power is transmitted and communicated between the power storage module 82 and the controller 83. Although only one power storage module is illustrated in FIG. 16, a plurality of power storage modules may be connected and each power storage module may be connected to the controller.

The controller 83 is connected to a charging device (charging power source) 84 or a load 85 via a power cable and a communication bus. When charging the power storage module 82, the controller 83 is connected to the charging device 84. The charging device 84 includes a direct current (DC) -DC converter or the like, and includes at least a charging voltage and charging current control unit 84a. For example, the charging voltage and charging current control unit 84a sets the charging voltage and charging current to predetermined values in accordance with the control of the controller 83 (main micro control unit 40).

When discharging the power storage module 82, the controller 83 is connected to the load 85. The power of the power storage module 82 is supplied to the load 85 via the controller 83. The load 85 connected to the controller 83 is a motor-type inverter circuit in an electric vehicle, a household power system, or the like.

The load 85 has at least a discharge current control unit 85a. For example, the discharge current control unit 85a sets the discharge current to a predetermined value in accordance with the control of the main micro control unit 40 of the controller 83. For example, the load 85 appropriately controls the magnitude of the discharge current (load current) flowing through the power storage module 82 by changing the load resistance.

An example of the configuration of the power storage module 82 will be described. Each part which comprises the electrical storage module 82 is accommodated in the exterior case of a predetermined shape, for example. The outer case is desirably made of a material having high conductivity and emissivity. By using a material having high conductivity and emissivity, excellent heat dissipation in the outer case can be obtained. By obtaining excellent heat dissipation, temperature rise in the outer case can be suppressed. Further, the opening of the outer case can be minimized or eliminated, and high dustproof and drip-proof properties can be realized. For the exterior case, for example, a material such as aluminum, an aluminum alloy, copper, or a copper alloy is used.

The power storage module 82 includes, for example, a positive electrode terminal 21, a negative electrode terminal 22, a power storage block BL as a power storage unit, a FET (Field （Effect Transistor), a voltage multiplexer 23, an ADC (Analog Digital Converter) 24, a temperature measurement unit 25, and a temperature multiplexer. 26, a monitoring unit 27, a temperature measurement unit 28, a current detection resistor 29, a current detection amplifier 30, an ADC 31, a sub-micro control unit 35, and a storage unit 36. A configuration different from the illustrated configuration may be added to the power storage module 82. For example, a regulator that generates a voltage for operating each unit of the power storage module 82 from the voltage of the power storage block BL may be added.

The power storage block BL is formed by connecting one or more submodules SMO. As an example, the power storage block BL is configured by connecting 16 submodules SMO1, submodule SMO2, submodule SMO3, submodule SMO4... And submodule SMO16 in series. In addition, when it is not necessary to distinguish each submodule, it is appropriately called a submodule SMO.

A submodule SMO is formed by connecting a plurality of storage batteries (cells). The submodule SMO has a configuration including, for example, an assembled battery in which eight cells are connected in parallel. For example, when a later-described lithium ion secondary battery is used as the cell, the capacity of the submodule SMO is, for example, about 24 Ah, and the voltage is, for example, about 3.0 V, which is substantially the same as the cell voltage.

The storage block BL is formed by connecting a plurality of submodules SMO. The power storage block BL has, for example, a configuration in which 16 submodules SMO are connected in series. In this case, the capacity is about 24 Ah, and the voltage is about 48 V (3.0 V × 16). The number of cells constituting the submodule SMO and the mode of cell connection can be changed as appropriate. Furthermore, the number of submodules SMO constituting the power storage block BL and the connection mode of the submodules SMO can be changed as appropriate. Note that discharging and charging may be performed in units of power storage blocks BL, and discharging and charging may be performed in units of submodules or cells.

The positive side of the submodule SMO1 is connected to the positive terminal 21 of the power storage module 82. The negative side of the submodule SMO 16 is connected to the negative terminal 22 of the power storage module 82. The positive terminal 21 is connected to the positive terminal of the controller 83. The negative terminal 22 is connected to the negative terminal of the controller 83.

Corresponding to the configuration of 16 submodules SMO, 16 FETs (FET1, FET2, FET3, FET4... FET16) are provided between the terminals of the submodule SMO. The FET is for performing, for example, passive cell balance control.

An outline of cell balance control performed by the FET will be described. For example, it is assumed that the deterioration of the submodule SMO2 progresses more than other submodules SMO, and the internal impedance of the submodule SMO2 increases. If the power storage module 82 is charged in this state, the submodule SMO2 is not charged to a normal voltage due to an increase in internal impedance. For this reason, variations occur in the voltage balance between the submodules SMO.

In order to eliminate the voltage balance variation between the submodules SMO, the FETs other than the FET2 are turned on, and the submodules SMO other than the submodule SMO2 are discharged to a predetermined voltage value. The FET is turned off after discharging. After the discharge, the voltage of each submodule SMO is, for example, a predetermined value (for example, 3.0 V, and the submodule SMO is balanced. Note that the cell balance control method is not limited to the passive method, but the so-called active method or Other known methods can be applied.

The voltage between the terminals of the submodule SMO is detected by a voltage detector (not shown). The voltage between the terminals of the submodule SMO is detected regardless of whether it is charging or discharging, for example. When the power storage module 82 is discharged, the voltage of each submodule SMO is detected by the voltage detection unit with a period of, for example, 250 ms (milliseconds).

The voltage (analog voltage data) of each submodule SMO detected by the voltage detection unit is supplied to a voltage multiplexer (MUX (Multiplexer)) 23. In this example, since the storage block is configured by 16 submodules SMO, 16 analog voltage data is supplied to the voltage multiplexer 23.

The voltage multiplexer 23 switches channels with a predetermined cycle, for example, and selects one analog voltage data from the 16 analog voltage data. One analog voltage data selected by the voltage multiplexer 23 is supplied to the ADC 24. Then, the voltage multiplexer 23 switches the channel and supplies the next analog voltage data to the ADC 24. That is, 16 analog voltage data are supplied from the voltage multiplexer 23 to the ADC 24 in a predetermined cycle.

The channel switching in the voltage multiplexer 23 is performed according to control by the sub-micro control unit 35 of the power storage module 82 or the main micro-control unit 40 of the controller 83.

The temperature measuring unit 25 detects the temperature of each submodule SMO. The temperature measuring unit 25 is composed of an element that detects a temperature, such as a thermistor. The temperature of the submodule SMO is detected with a predetermined cycle, for example, whether charging or discharging. Since the temperature of the submodule SMO and the temperature of the cells constituting the submodule SMO are not significantly different, in one embodiment, the temperature of the submodule SMO is measured. The individual temperatures of the eight cells may be measured, and the average value of the temperatures of the eight cells may be used as the temperature of the submodule SMO.

Analog temperature data indicating the temperature of each submodule SMO detected by the temperature measuring unit 25 is supplied to the temperature multiplexer (MUX) 26. In this example, since the power storage block BL is configured by 16 submodules SMO, 16 analog temperature data are supplied to the temperature multiplexer 26.

The temperature multiplexer 26 switches channels with a predetermined cycle, for example, and selects one analog temperature data from the 16 analog temperature data. One analog temperature data selected by the temperature multiplexer 26 is supplied to the ADC 24. Then, the temperature multiplexer 26 switches the channel and supplies the next analog temperature data to the ADC 24. That is, 16 analog temperature data are supplied from the temperature multiplexer 26 to the ADC 24 in a predetermined cycle.

Note that the channel switching in the temperature multiplexer 26 is performed according to control by the sub micro control unit 35 of the power storage module 82 or the main micro control unit 40 of the controller 83.

The ADC 24 converts the analog voltage data supplied from the voltage multiplexer 23 into digital voltage data. The ADC 24 converts the analog voltage data into, for example, 14 to 18 bit digital voltage data. As the conversion method in the ADC 24, various methods such as a successive approximation method and a ΔΣ (delta sigma) method can be applied.

The ADC 24 includes, for example, an input terminal, an output terminal, a control signal input terminal to which a control signal is input, and a clock pulse input terminal to which a clock pulse is input (the illustration of these terminals is omitted). ) Analog voltage data is input to the input terminal. The converted digital voltage data is output from the output terminal.

For example, a control signal (control command) supplied from the controller 83 is input to the control signal input terminal. The control signal is an acquisition instruction signal for instructing acquisition of analog voltage data supplied from the voltage multiplexer 23, for example. When the acquisition instruction signal is input, the analog voltage data is acquired by the ADC 24, and the acquired analog voltage data is converted into digital voltage data. Then, digital voltage data is output via the output terminal in accordance with the synchronizing clock pulse input to the clock pulse input terminal. The output digital voltage data is supplied to the monitoring unit 27.

Furthermore, an acquisition instruction signal for instructing acquisition of analog temperature data supplied from the temperature multiplexer 26 is input to the control signal input terminal. In response to the acquisition instruction signal, the ADC 24 acquires analog temperature data. The acquired analog temperature data is converted into digital temperature data by the ADC 24. The analog temperature data is converted into, for example, 14-18 bit digital temperature data. The converted digital temperature data is output via the output terminal, and the output digital temperature data is supplied to the monitoring unit 27. In addition, it is good also as a structure by which ADC which processes each of voltage data and temperature data is provided separately. The functional block of the ADC 24 may have a function of a comparator that compares a voltage or temperature with a predetermined value.

For example, 16 digital voltage data and 16 digital temperature data are time-division multiplexed and transmitted from the ADC 24 to the monitoring unit 27. An identifier for identifying the submodule SMO may be described in the header of the transmission data to indicate which submodule SMO voltage or temperature. In this example, the digital voltage data of each submodule SMO obtained with a predetermined period and converted into digital data by the ADC 24 corresponds to the voltage information. Analog voltage data may be used as voltage information, and digital voltage data subjected to correction processing or the like may be used as voltage information.

The temperature measuring unit 28 measures the temperature of the entire power storage module 82. The temperature in the outer case of the power storage module 82 is measured by the temperature measurement unit 28. Analog temperature data measured by the temperature measurement unit 28 is supplied to the temperature multiplexer 26, and is supplied from the temperature multiplexer 26 to the ADC 24. Then, the analog temperature data is converted into digital temperature data by the ADC 24. Digital temperature data is supplied from the ADC 24 to the monitoring unit 27.

The power storage module 82 has a current detection unit that detects the value of the current (load current) flowing through the current path of the power storage module 82. The current detection unit detects a current value flowing through the 16 submodules SMO. The current detection unit includes, for example, a current detection resistor 29 connected between the negative electrode side of the submodule SMO16 and the negative electrode terminal 22, and a current detection amplifier 30 connected to both ends of the current detection resistor 29. Analog current data is detected by the current detection resistor 29. For example, the analog current data is detected with a predetermined cycle regardless of whether it is being charged or discharged.

Detected analog current data is supplied to the current detection amplifier 30. The analog current data is amplified by the current detection amplifier 30. The gain of the current detection amplifier 30 is set to about 50 to 100 times, for example. The amplified analog current data is supplied to the ADC 31.

The ADC 31 converts the analog current data supplied from the current detection amplifier 30 into digital current data. The ADC 31 converts the analog current data into, for example, 14-18 bit digital current data. Various conversion methods such as a successive approximation method and a ΔΣ (delta sigma) method can be applied to the conversion method in the ADC 31.

The ADC 31 includes, for example, an input terminal, an output terminal, a control signal input terminal to which a control signal is input, and a clock pulse input terminal to which a clock pulse is input (illustration of these terminals is omitted). . Analog current data is input to the input terminal. Digital current data is output from the output terminal.

For example, a control signal (control command) supplied from the controller 83 is input to the control signal input terminal of the ADC 31. The control signal is, for example, an acquisition instruction signal that instructs acquisition of analog current data supplied from the current detection amplifier 30. When the acquisition instruction signal is input, the analog current data is acquired by the ADC 31, and the acquired analog current data is converted into digital current data. Then, digital current data is output from the output terminal in accordance with the synchronizing clock pulse input to the clock pulse input terminal. The output digital current data is supplied to the monitoring unit 27. This digital current data is an example of current information. Note that the ADC 24 and the ADC 31 may be configured as the same ADC.

The monitoring unit 27 monitors the digital voltage data and digital temperature data supplied from the ADC 24, and monitors whether there is an abnormality in the submodule SMO. For example, if the voltage indicated by the digital voltage data is in the vicinity of a voltage that is a standard for overcharge or a voltage that is a standard for overdischarge, there is an abnormality that indicates that there is an abnormality or that an abnormality may occur Generate a notification signal. Further, the monitoring unit 27 similarly generates an abnormality notification signal when the temperature of the submodule SMO or the temperature of the entire power storage module 82 is larger than the threshold value.

Further, the monitoring unit 27 monitors digital current data supplied from the ADC 31. When the current value indicated by the digital current data is larger than the threshold value, the monitoring unit 27 generates an abnormality notification signal. The abnormality notification signal generated by the monitoring unit 27 is transmitted to the sub-micro control unit 35 by the communication function of the monitoring unit 27.

The monitoring unit 27 monitors the presence / absence of the abnormality described above, and transmits the digital voltage data for each of the 16 submodules SMO supplied from the ADC 24 and the digital current data supplied from the ADC 31 to the sub-micro control unit 35. Digital voltage data and digital current data for each sub-module SMO may be directly supplied to the sub-micro control unit 35 without going through the monitoring unit 27. The transmitted digital voltage data and digital current data for each sub-module SMO are input to the sub-micro control unit 35. Further, digital temperature data supplied from the ADC 24 is supplied from the monitoring unit 27 to the sub-micro control unit 35.

The sub-micro control unit 35 is configured by a CPU (Central Processing Unit) having a communication function and controls each part of the power storage module 82. For example, when an abnormality notification signal is supplied from the monitoring unit 27, the sub micro control unit 35 notifies the main micro control unit 40 of the controller 83 of the abnormality using the communication function. In response to this notification, the main micro control unit 40 appropriately executes processing such as stopping charging or discharging. Note that the sub and main notations in the sub-micro control unit and the main micro-control unit are for convenience of explanation, and have no special meaning.

Between the sub-micro control unit 35 and the main micro-control unit 40, bidirectional communication conforming to serial communication standards such as I2C, SMBus (System Management Bus), SPI (Serial Peripheral Interface), CAN, etc. Done. Communication may be wired or wireless.

The digital voltage data is input from the monitoring unit 27 to the sub-micro control unit 35. For example, digital voltage data for each submodule SMO when the power storage module 82 is discharged is input to the sub-micro control unit 35.

Furthermore, the magnitude of the load current (digital current data) when a load is connected to the power storage module 82 is input from the monitoring unit 27 to the sub-micro control unit 35. Digital temperature data indicating the temperature for each sub module SMO and the temperature in the power storage module 82 is input to the sub micro control unit 35.

The sub-micro control unit 35 transmits the input digital voltage data for each sub-module SMO, digital temperature data indicating the temperature for each sub-module SMO, digital current data, and the like to the main micro-control unit 40.

The storage unit 36 includes a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. For example, the storage unit 36 stores a program executed by the sub-micro control unit 35. The storage unit 36 is further used as a work area when the sub-micro control unit 35 executes processing.

In the storage unit 36, history information regarding the power storage module 82 is stored. The history information includes, for example, charge conditions such as a charge rate, a charge time, and the number of times of charge, a discharge rate, a discharge time, a discharge condition of the number of times of discharge, temperature information, and the like. These pieces of information may be recorded in units of the power storage block BL, the submodule SMO, and the storage battery. The sub-micro control unit 35 may perform processing referring to history information.

(Configuration of controller)
An example of the configuration of the controller 83 will be described. The controller 83 manages charging and discharging for one or a plurality of power storage modules 82. Specifically, starting and stopping of charging of the power storage module 82, starting and stopping of discharging of the power storage module 82, setting of a charging rate and a discharging rate, and the like are performed. For example, the controller 83 is configured to have an exterior case in the same manner as the power storage module 82. Furthermore, as a function of the controller 83, a rapid deterioration detection function according to the present technology is incorporated. The sub-micro control unit 35 may have a rapid deterioration detection function.

The controller 83 includes a main micro control unit 40, a positive terminal 41, a negative terminal 42, a positive terminal 43, a negative terminal 44, a charge control unit 45, a discharge control unit 46, a switch SW1, and a switch SW2. The switch SW1 is connected to the terminal 50a or the terminal 50b. The switch SW2 is connected to the terminal 51a or the terminal 51b.

The positive terminal 41 is connected to the positive terminal 21 of the power storage module 82. The negative terminal 42 is connected to the negative terminal 22 of the power storage module 82. The positive terminal 43 and the negative terminal 44 are connected to a charging device 84 or a load 85 connected to the controller 83.

The main micro control unit 40 is constituted by, for example, a CPU having a communication function, and controls each part of the controller 83. The main micro control unit 40 controls charging and discharging according to an abnormality notification signal transmitted from the sub micro control unit 35 of the power storage module 82. For example, when the possibility of overcharging is notified by the abnormality notification signal, the main micro control unit 40 turns off at least the switching element of the charging control unit 45 and stops charging. For example, when the risk of overdischarge is notified by the abnormality notification signal, the main micro control unit 40 turns off at least the switching element of the discharge control unit 46 and stops the discharge.

For example, when the alarm signal notifies that the sub-module SMO is deteriorated, the main micro control unit 40 turns off the switching elements of the charge control unit 45 and the discharge control unit 46, and uses the power storage module 82. Cancel. For example, when the power storage module 82 is used as a power source for backup, the use of the power storage module 82 is stopped at an appropriate timing without immediately stopping the use of the power storage module 82.

The main micro control unit 40 manages the charging and discharging of the power storage module 82 and refers to history information such as the voltage, temperature, and cycle number of the sub module SMO transmitted from the sub micro control unit 35, which will be described later. Control to perform the discharge method. The sub-micro control unit 35 may have a part of the functions of the main micro-control unit 40 described below.

The main micro control unit 40 can communicate with the CPU and the like included in the charging device 84 and the load 85. The main micro control unit 40 sets a charging voltage and a charging rate (a magnitude of charging current) for the power storage module 82, and transmits the set charging voltage and charging rate to the charging device 84. The charging voltage and charging current control unit 84a appropriately sets the charging voltage and charging current according to the charging voltage and charging rate transmitted from the main micro control unit 40.

The main micro control unit 40 sets the discharge rate (the magnitude of the discharge current) of the electricity storage module 82 and transmits the set discharge rate to the load 85. The discharge current control unit 85a of the load 85 appropriately sets the load so that the discharge current according to the discharge rate transmitted from the main micro control unit 40 is obtained.

The charge control unit 45 includes a charge control switch 45a and a diode 45b connected in parallel with the charge control switch 45a in the forward direction with respect to the discharge current. The discharge control unit 46 includes a discharge control switch 46a and a diode 46b connected in parallel to the charge control current in parallel with the discharge control switch 46a. As the charge control switch 45a and the discharge control switch 46a, for example, an IGBT (Insulated Gate Bipolar Transistor) or a MOSFET (Metal Metal Oxide Semiconductor Semiconductor Field Effect Transistor) can be used. Note that the charge control unit 45 and the discharge control unit 46 may be inserted into the negative power supply line.

The storage unit 47 includes a ROM, a RAM, and the like. In the storage unit 47, for example, a program executed by the main micro control unit 40 is stored. The storage unit 47 is used as a work area when the main micro control unit 40 executes processing. The above history information may be stored in the storage unit 47.

The switch SW1 is connected to the positive power supply line connected to the positive terminal 43. When the power storage module 82 is charged, the switch SW1 is connected to the terminal 50a, and when the power storage module 82 is discharged, the switch SW1 is connected to the terminal 50b.

The switch SW2 is connected to the negative power supply line connected to the negative terminal 44. When the power storage module 82 is charged, the switch SW2 is connected to the terminal 51a, and when the power storage module 82 is discharged, the switch SW2 is connected to the terminal 51b. Switching of the switch SW1 and the switch SW2 is controlled by the main micro control unit 40.

"Residential power storage device"
An example in which the present technology is applied to a residential power storage device will be described with reference to FIG. For example, in the power storage device 100 for the house 101, electric power is supplied from the centralized power system 102 such as the thermal power generation 102a, the nuclear power generation 102b, and the hydroelectric power generation 102c through the power network 109, the information network 112, the smart meter 107, the power hub 108, and the like. It is supplied to the power storage device 103. At the same time, power is supplied to the power storage device 103 from an independent power source such as the home power generation device 104. The electric power supplied to the power storage device 103 is stored. Electric power used in the house 101 is fed using the power storage device 103. The same power storage device can be used not only for the house 101 but also for buildings. The power storage device 103 is obtained by connecting a plurality of power storage modules in parallel.

The house 101 is provided with a home power generation device 104, a power consumption device 105, a power storage device 103, a control device 110 that controls each device, a smart meter 107, and a sensor 111 that acquires various types of information. Each device is connected by a power network 109 and an information network 112. As the home power generation device 104, a solar cell, a fuel cell, or the like is used, and the generated power is supplied to the power consumption device 105 and / or the power storage device 103. The power consuming device 105 is a refrigerator 105a, an air conditioner (air conditioner) 105b, a television receiver (television) 105c, a bath (bus) 105d, and the like. Furthermore, the electric power consumption device 105 includes an electric vehicle 106. The electric vehicle 106 is an electric vehicle 106a, a hybrid car 106b, and an electric motorcycle 106c.

The power storage device 103 is composed of a secondary battery or a capacitor. For example, it is constituted by a lithium ion secondary battery. A plurality of power storage modules can be used as the power storage device 103. The lithium ion secondary battery may be a stationary type or used in the electric vehicle 106. The smart meter 107 has a function of measuring the usage amount of commercial power and transmitting the measured usage amount to an electric power company. The power network 109 may be any one or a combination of DC power supply, AC power supply, and non-contact power supply.

The various sensors 111 are, for example, human sensors, illuminance sensors, object detection sensors, power consumption sensors, vibration sensors, contact sensors, temperature sensors, infrared sensors, and the like. Information acquired by the various sensors 111 is transmitted to the control device 110. Based on the information from the sensor 111, the weather condition, the human condition, etc. can be grasped, and the power consumption device 105 can be automatically controlled to minimize the energy consumption. Furthermore, the control device 110 can transmit information regarding the house 101 to an external power company or the like via the Internet.

The power hub 108 performs processing such as branching of power lines and DC / AC conversion. The communication method of the information network 112 connected to the control device 110 includes a method using a communication interface such as UART (Universal Asynchronous Receiver-Transmitter), Bluetooth (registered trademark), ZigBee (registered trademark). And a sensor network based on a wireless communication standard such as Wi-Fi (registered trademark). The Bluetooth (registered trademark) system is applied to multimedia communication and can perform one-to-many connection communication. ZigBee uses the physical layer of IEEE (Institute of Electrical and Electronics Electronics) (802.15.4). IEEE 802.15.4 is the name of a short-range wireless network standard called PAN (Personal Area Network) or W (Wireless) PAN.

The control device 110 is connected to an external server 113. The server 113 may be managed by any one of the house 101, the power company, and the service provider. The information transmitted and received by the server 113 is, for example, information related to power consumption information, life pattern information, power charges, weather information, natural disaster information, and power transactions. These pieces of information may be transmitted / received from a power consuming device (for example, a television receiver) in the home, or may be transmitted / received from a device outside the home (for example, a mobile phone). Such information may be displayed on a device having a display function, for example, a television receiver, a mobile phone, a PDA (Personal Digital Assistant) or the like.

The control device 110 that controls each unit includes a CPU, a RAM, a ROM, and the like, and is stored in the power storage device 103 in this example. As a function of the control device 110, for example, a function such as the monitoring unit 27 or a function such as the controller 83 can be applied. The control device 110 is connected to the power storage device 103, the home power generation device 104, the power consumption device 105, the various sensors 111, the server 113 and the information network 112, and adjusts, for example, the amount of commercial power used and the amount of power generation. have. In addition, you may provide the function etc. which carry out an electric power transaction in an electric power market.

As described above, electric power is generated not only from the centralized power system 102 such as the thermal power generation 102a, the nuclear power generation 102b, and the hydroelectric power generation 102c but also from the home power generation device 104 (solar power generation, wind power generation) to the power storage device 103. Can be stored. Therefore, even if the generated power of the home power generation device 104 fluctuates, it is possible to perform control such that the amount of power transmitted to the outside is constant or discharge is performed as necessary. For example, the electric power obtained by solar power generation is stored in the power storage device 103, and midnight power with a low charge is stored in the power storage device 103 at night, and the power stored by the power storage device 103 is discharged during a high daytime charge. You can also use it.

In this example, the example in which the control device 110 is stored in the power storage device 103 has been described. However, the control device 110 may be stored in the smart meter 107 or may be configured independently. Furthermore, the power storage device 100 may be used for a plurality of homes in an apartment house, or may be used for a plurality of detached houses.

<3. Modification>
As mentioned above, although embodiment of this technique was described concretely, it is not limited to each above-mentioned embodiment, Various deformation | transformation based on the technical idea of this technique is possible.
The configurations, methods, steps, shapes, materials, numerical values, and the like of the above-described embodiments can be combined with each other without departing from the gist of the present technology.
For example, the numerical values, structures, shapes, materials, raw materials, manufacturing processes and the like given in the above-described embodiments and examples are merely examples, and different numerical values, structures, shapes, materials, raw materials, A manufacturing process or the like may be used.
The configurations, methods, processes, shapes, materials, numerical values, and the like of the above-described embodiments and examples can be combined with each other without departing from the gist of the present technology.

In addition, this technique can also take the following structures.
(1)
A capacity change amount calculation unit for calculating a change amount of the full charge capacity or the capacity maintenance rate by inputting the full charge capacity or the capacity maintenance rate of the secondary battery and the elapsed time; and
A battery pack comprising: a rapid deterioration determination unit that determines deterioration based on a threshold value determination based on a change amount calculated by the capacity change amount calculation unit.
(2)
The change amount of the full charge capacity or the capacity maintenance rate calculated by the capacity change amount calculation unit is the battery pack according to (1), which is calculated by linear regression analysis.
(3)
The battery pack according to (1) or (2), wherein the rapid deterioration determined by the rapid deterioration determination unit is notified.
(4)
The battery pack according to (1), wherein the capacity maintenance rate of the secondary battery is determined based on a threshold value, and the case where the capacity maintenance rate is smaller than the threshold value is subject to deterioration determination.
(5)
A difference between the predicted value based on the deterioration prediction formula and the full charge capacity or capacity maintenance rate of the secondary battery is determined based on a threshold value, and the case where the difference value is larger than the threshold value is subject to deterioration determination (1) or ( The battery pack according to 3).
(6)
A power storage device that includes the battery pack according to (1) and supplies electric power to an electronic device connected to the battery pack.
(7)
Calculate the amount of change in the full charge capacity or capacity maintenance rate from the full charge capacity or capacity maintenance rate of the secondary battery and the elapsed time,
A method for detecting deterioration of a secondary battery, wherein deterioration is detected based on a threshold value determination for a calculated change amount.
(8)
The amount of change in the full charge capacity or capacity maintenance rate is the secondary battery deterioration detection method according to (7), which is calculated by linear regression analysis.

DESCRIPTION OF SYMBOLS 1 ... Secondary battery 2 ... Battery capacity calculator 3 ... Maintenance rate calculator 5, 15 ... Maintenance rate memory | storage device 6, 18 ... Linear regression analyzer 7, 19 ... Sudden Degradation determiner 8, 20 ... Rapid deterioration notification device 16 ... Maintenance rate threshold value determiner 17 ... Maintenance rate difference determiner

Claims (8)

1. A capacity change amount calculation unit for calculating a change amount of the full charge capacity or the capacity maintenance rate by inputting the full charge capacity or the capacity maintenance rate of the secondary battery and the elapsed time; and
   A battery pack comprising: a rapid deterioration determination unit that determines deterioration based on a threshold value determination based on a change amount calculated by the capacity change amount calculation unit.
2. The battery pack according to claim 1, wherein the change amount of the full charge capacity or the capacity maintenance ratio calculated by the capacity change amount calculation unit is calculated by linear regression analysis.
3. The battery pack according to claim 1, wherein the rapid deterioration determined by the rapid deterioration determination unit is notified.
4. 2. The battery pack according to claim 1, wherein the capacity maintenance rate of the secondary battery is determined based on a threshold value, and the case where the capacity maintenance rate is smaller than the threshold value is subject to deterioration determination.
5. The prediction value based on the deterioration prediction formula and the difference value between the full charge capacity or the capacity maintenance rate of the secondary battery are determined based on a threshold value, and the case where the difference value is larger than the threshold value is subject to deterioration determination. Battery pack.
6. A power storage device that has the battery pack according to claim 1 and supplies electric power to an electronic device connected to the battery pack.
7. Calculate the amount of change in the full charge capacity or capacity maintenance rate from the full charge capacity or capacity maintenance rate of the secondary battery and the elapsed time,
   A method for detecting deterioration of a secondary battery, wherein deterioration is detected based on a threshold value determination for a calculated change amount.
8. The method for detecting deterioration of a secondary battery according to claim 7, wherein the amount of change in the full charge capacity or capacity maintenance rate is calculated by linear regression analysis.

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