Patent Description:
Conventionally, there is known a system that analyzes characteristics such as a maximum capacity of a battery (also referred to as full charge capacity) (see, for example, Patent Document <NUM>). Patent Document <NUM>: <CIT>.

Document <CIT> describes a method for determining the health of a battery. The battery health is determined by estimating a battery anode capacity, battery cathode capacity, and cyclable lithium capacity. Determining electrode and lithium capacity includes determining anode and cathode open cell voltages (OCV) at the beginning of battery life, and estimating the full cell OCV from the individual (half-cell) OCV values. Once the beginning of battery life information is known, the state of charge (SOC) for a battery is measured during battery life. The SOC measurements may be captured at a plurality of different levels. The cathode capacity, anode capacity, and cycle mobile lithium capacity are then determined from the beginning of life OCV data and plurality of SOC data.

Document <CIT> describes a battery safety evaluation apparatus which includes an estimator, a calculator, and an evaluator. The estimator estimates an estimation value of an inner state parameter of a battery to be evaluated on the basis of data of its voltage and current measured in charging or discharging it. The calculator calculates an index regarding swelling risk of the battery on the basis of first reference data. The evaluator evaluates, on the basis of the index, a battery swelling risk of the battery to evaluate safety of the battery. The battery is a secondary battery. The first reference data is reference data considered to correspond to the battery from the reference data on the basis of estimation value. The reference data indicates at least one of relationships between a positive electrode capacity, a negative electrode capacity and an SOC deviation of a secondary battery.

For analyzing battery characteristics with high accuracy, it is necessary to mount a high-performance analysis system in each battery.

An analysis device of the present invention is defined in claim <NUM>.

The data acquisition unit may be configured to acquire the identification data in which module identification data for identifying the battery modules and cell identification data for identifying the battery cells are associated with each other. The data analysis unit may be configured to analyze the characteristics related to the charging capacity of the battery cell for each of the battery modules.

The analysis device may further include an analysis data recording unit configured to record the measurement data acquired by the data acquisition unit over time, in association with the identification data.

The data analysis unit may be configured to generate control data for controlling the battery cell based on the analysis result. The data transmission unit may be configured to transmit the transmission data including the control data.

The data analysis unit may be configured to calculate a remaining capacity of each of the battery cells in each of the battery modules based on the measurement data. The data analysis unit may be configured to generate the control data for discharging at least one of the battery cells in which the remaining capacity is not smallest to reduce a difference between the remaining capacity of the at least one of the battery cells and the remaining capacity of the battery cell in which the remaining capacity is smallest.

The data analysis unit may be configured to generate replacement time data indicating a time to replace the battery cell based on the analysis result. The data transmission unit may be configured to transmit the transmission data including the replacement time data.

The data analysis unit may be configured to generate failure data indicating a failure of the battery cell based on the analysis result. The data transmission unit may be configured to transmit the transmission data including the failure data.

The data analysis unit may be configured to analyze the characteristics related to the charging capacity of the battery cell based on derivation characteristics of capacitance-voltage characteristics during charging or discharging of the battery cell.

The data acquisition unit may be configured to acquire the analysis data including temperature data indicating a temperature of the battery cell at a time of measuring the capacitance-voltage characteristics. The data analysis unit may be configured to correct the analysis by the derivation characteristics based on the temperature of the battery cell.

The analysis device may further include a reference characteristics recording unit having recorded thereon reference characteristics of the derivation characteristics of each of the battery cells. The reference characteristics may include one or more reference feature points. The data analysis unit may be configured to analyze the battery cell based on a measurement feature point in the derivation characteristics of the battery cell and the one or more reference feature points in the reference characteristics.

The reference characteristics recording unit may be configured to record at least one of the reference characteristics at the charging of the battery cell or the reference characteristics at the discharging of the battery cell. The data analysis unit may be configured to select the reference characteristics to be compared with the derivation characteristics, based on which of data obtained during the charging or data obtained during the discharging the measurement data of the battery cell is.

The data analysis unit may be configured to calculate a deterioration rate of the battery cell based on a deterioration amount of the battery cell calculated from the derivation characteristics.

The data analysis unit may be configured to calculate a measurement interval for measuring data related to the charging and discharging of the battery cell, based on the deterioration rate of the battery cell. The data transmission unit may be configured to transmit the transmission data corresponding to the measurement interval.

The data analysis unit may be configured to calculate, based on a deviation amount of the charging capacities between two or more of the battery cells, the deviation amount being calculated from the derivation characteristics of the two or more of the battery cells, a deviation rate of the charging capacities between the two or more of the battery cells.

The data analysis unit may be configured to calculate the measurement interval for measuring the data related to the charging and discharging of the two or more of the battery cells based on the deviation rate of the two or more of the battery cells. The data transmission unit may be configured to transmit the transmission data corresponding to the measurement interval.

An analysis system of the present invention is defined in claim <NUM>.

A battery module analysis method of the present invention is defined in claim <NUM>.

Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the claimed invention. In addition, not all of the combinations of features described in the embodiments are essential to the solving means of the invention.

<FIG> shows a configuration example of an analysis system <NUM> according to an embodiment of the present invention. The analysis system <NUM> collects measurement data obtained by measuring characteristics of one or more battery modules <NUM> via a network <NUM>, and analyzes a state of the battery modules <NUM>. The analysis system <NUM> of the present example includes an analysis device <NUM> and one or more analysis data transmission units <NUM>.

Each of the battery modules <NUM> includes one or more battery cells <NUM>. The battery cell <NUM> has a configuration with which electrical power can be generated by the battery cell alone. For example, each of the battery cells <NUM> includes a negative electrode, a positive electrode, and a body portion that generates electrical power between both electrodes. The battery module <NUM> may include a plurality of battery cells <NUM> connected in series. Alternatively, the battery module <NUM> may include a plurality of battery cells <NUM> connected in parallel. A group of battery cells <NUM> electrically connected in series or parallel may be given as a single battery module <NUM>. Alternatively, a group of battery cells <NUM> accommodated in a common housing may be given as a single battery module <NUM>.

The analysis data transmission unit <NUM> transmits analysis data for analyzing characteristics of the battery module <NUM> to the analysis device <NUM> via the network <NUM>. The analysis data transmission unit <NUM> may be provided for each battery module <NUM>, or may be provided in common for the plurality of battery modules <NUM>. The analysis data transmission unit <NUM> may be provided in a housing of the battery module <NUM>. In another example, the analysis data transmission unit <NUM> may be provided apart from the battery module <NUM>. In this case, it is preferable for the analysis data transmission unit <NUM> to be provided while being communicable with the battery module <NUM>.

The analysis data includes measurement data obtained by measuring characteristics related to charging and discharging of the one or more battery cells <NUM> included in the battery module <NUM>. The characteristics related to charging and discharging may be electrical characteristics of the battery cell <NUM> in at least one of timings including a start of charging, during charging, an end of charging, a start of discharging, during discharging, or an end of discharging of the battery cell <NUM>. The electrical characteristics may include at least one of an interpolar voltage, an output current, a remaining capacity value, or an output resistance of the battery cell <NUM>. Further, the electrical characteristics may include a temporal change of at least one of the interpolar voltage or the output current of the battery cell <NUM>. Furthermore, the electrical characteristics may include a temporal change such as deterioration, of at least one of the remaining capacity value or the output resistance of the battery cell <NUM>. Further, the interpolar voltage described above may be an interpolar voltage of the battery module <NUM> including the plurality of battery cells <NUM> connected in series or an interpolar voltage of a unit in which the plurality of battery modules <NUM> are combined.

The analysis data includes identification data associated with measurement data. The identification data includes at least one of module identification data for identifying the battery module <NUM> or cell identification data for identifying the battery cell <NUM>. The module identification data may be serial numbers allocated to the plurality of battery modules <NUM>. The cell identification data may be a serial number allocated to the one or more battery cells <NUM> included in the battery module <NUM>.

The network <NUM> is, for example, the Internet or a local area network, though is not limited thereto. The network <NUM> may be a dedicated network for connecting the plurality of analysis data transmission units <NUM> and the analysis device <NUM>, or may be a general-purpose network for also performing communication other than communication between the analysis data transmission unit <NUM> and the analysis device <NUM>.

The analysis device <NUM> acquires analysis data of each of the battery modules <NUM> via the network <NUM>. The analysis device <NUM> analyzes characteristics related to a charging capacity of the one or more battery cells <NUM> included in the battery module <NUM> based on the analysis data. In the present specification, when not mentioned in particular, a unit of a battery capacity is ampere-hour (Ah). The analysis device <NUM> may be a device that processes information using a single computer, or may be a device that performs decentralized information processing using a plurality of computers. The characteristics related to the charging capacity may include at least one of a full charge capacity of the battery cell <NUM>, a remaining capacity of the battery cell <NUM>, a measurement value of an internal resistance of the battery cell <NUM>, a temporal change amount of deterioration or the like regarding these characteristics, or a variation amount of these characteristics among the battery cells <NUM> included in the battery module <NUM>. Note that in the present specification, the full charge capacity or the remaining capacity may be referred to as the charging capacity (or capacity). That is, the charging capacity (or capacity) in the present specification conceptually includes both the full charge capacity and the remaining capacity.

The analysis device <NUM> may transmit an analysis result to outside. The analysis device <NUM> may transmit the analysis result to a device including the analysis data transmission unit <NUM>, or may transmit the analysis result to a device different from the analysis data transmission unit <NUM>.

<FIG> illustrates a detailed configuration example of the analysis system <NUM>. The analysis system <NUM> of the present example includes, in addition to the configuration shown in <FIG>, a battery management device <NUM> and a measurement unit <NUM>. The battery management device <NUM> and the measurement unit <NUM> may be provided with respect to each of the battery modules <NUM>. <FIG> shows the battery management device <NUM>, the measurement unit <NUM>, and the analysis data transmission unit <NUM> accompanying one battery module <NUM>. Note that each of the analysis data transmission unit <NUM>, the battery management device <NUM>, and the measurement unit <NUM> may be incorporated into the battery module <NUM>, or may be attached separately to a single battery module <NUM>.

The measurement unit <NUM> generates measurement data obtained by measuring electrical characteristics of the battery module <NUM>. The measurement unit <NUM> may include at least one of an ammeter or a voltmeter. The analysis data transmission unit <NUM> transmits, to the analysis device <NUM>, analysis data including the measurement data generated by the measurement unit <NUM> and identification data of the battery module <NUM> or the like.

The battery management device <NUM> receives transmission data from the analysis device <NUM>. The battery management device <NUM> may control the battery module <NUM> based on the received transmission data. Further, the battery management device <NUM> may also provide information corresponding to the received transmission data to a user of the battery module <NUM>. As an example, the battery management device <NUM> may charge and discharge each of the battery cells <NUM> based on the remaining capacity of each of the battery cells <NUM> indicated in the transmission data. In another example, the transmission data may include control data for controlling each of the battery cells <NUM> to charge and discharge. Further, the battery management device <NUM> may provide information related to the capacity of each of the battery cells <NUM> to the user.

The battery management device <NUM> may be included in the same device as the analysis data transmission unit <NUM>. In this case, the analysis device <NUM> may transmit and receive transmission data and analysis data using the same communication path. Further, the battery management device <NUM> may be a different device from the analysis data transmission unit <NUM>. For example, the analysis data transmission unit <NUM> may be a device managed by the user who is using the battery module <NUM>, and the battery management device <NUM> may be a device managed by a provider who provided the battery module <NUM> to the user. In this case, the analysis device <NUM> may transmit and receive transmission data and analysis data using different communication paths. In another example, the battery management device <NUM> and the analysis data transmission unit <NUM> may both be devices managed by the user, or may both be devices managed by the provider.

The analysis device <NUM> of the present example includes a data acquisition unit <NUM>, a data analysis unit <NUM>, and a data transmission unit <NUM>. The analysis device <NUM> may further include an analysis data recording unit <NUM>. The data acquisition unit <NUM> acquires analysis data via the network <NUM>. The data acquisition unit <NUM> may record the acquired analysis data in the analysis data recording unit <NUM>. The analysis data recording unit <NUM> records the analysis data for each identification data.

The data analysis unit <NUM> analyzes the characteristics related to the charging capacity of at least one of the battery cells <NUM> based on the analysis data acquired by the data acquisition unit <NUM>. The data analysis unit <NUM> may sequentially analyze the analysis data acquired by the data acquisition unit <NUM>, or may read the analysis data from the analysis data recording unit <NUM> and analyze the read data.

The data transmission unit <NUM> transmits transmission data corresponding to an analysis result obtained by the data analysis unit <NUM> to the battery management device <NUM> via the network <NUM>. The data transmission unit <NUM> may determine a transmission destination of the transmission data based on the identification data included in the analysis data used for the analysis by the data analysis unit <NUM>. For example, the data transmission unit <NUM> may store therein in advance correspondence information in which the identification data and the transmission destination are associated with each other. Further, the analysis data may also include information that designates a transmission destination of the transmission data. In this case, the battery management device <NUM> may notify the analysis data transmission unit <NUM> of the information that designates the transmission destination.

According to the analysis system <NUM> of the present example, since the analysis device <NUM> is not provided for each battery module <NUM>, costs of the battery modules <NUM> can be reduced. Further, performance of the analysis device <NUM> is improved, and thus an analysis of high accuracy can be performed with ease.

<FIG> shows an example of the analysis data. In the example of <FIG>, one piece of analysis data includes analysis data related to one battery module <NUM>. In another example, one piece of analysis data may include analysis data related to the plurality of battery modules <NUM>.

The analysis data includes identification data and measurement data Me. The identification data includes at least one of module identification data Mo or cell identification data Ce. In the analysis data in the example of <FIG>, the module identification data Mo and the cell identification data Ce are associated with each other. In this case, the data analysis unit <NUM> may analyze the characteristics related to the charging capacity of the battery cell <NUM> for each battery module <NUM>. As an example, the data analysis unit <NUM> may analyze variations in the capacities of the battery cells <NUM> included in the battery module <NUM>.

The measurement data Me is data for each battery cell <NUM>. The analysis data recording unit <NUM> may record the measurement data acquired over time by the data acquisition unit <NUM>, in association with the identification data. When the identification data includes the cell identification data Ce, the measurement data Me is associated with the cell identification data Ce. In this case, the data analysis unit <NUM> analyzes the measurement data Me for each cell identification data Ce, and analyzes the characteristics related to the charging capacities of the individual battery cells <NUM>.

When the identification data does not include the cell identification data Ce, each measurement data Me is associated with common module identification data Mo. In this case, the data analysis unit <NUM> analyzes each measurement data Me and analyzes the characteristics related to the charging capacities of the battery cells <NUM>. Note that when the analyzed characteristics do not specify which battery cell <NUM> the characteristics belong to, the data analysis unit <NUM> analyzes at least one of a maximum value, minimum value, average value, or the like of the capacities of the battery cells <NUM> included in the battery module <NUM>, for example.

In the example of <FIG>, the analysis data further includes temperature data T and driving time data L. The temperature data T indicates a temperature of the battery cell <NUM> or the battery module <NUM> when the measurement data is measured. The temperature data T may indicate a peripheral temperature of the battery module <NUM> when the measurement data is measured. The temperature data T may be common data with respect to the battery cells <NUM> in the battery module <NUM>.

The driving time data L may indicate a cumulative driving time of each of the battery cells <NUM>. The driving time may be an elapsed time since the battery cell <NUM> is started to be used, or may be a cumulative time obtained by accumulating a time during which the battery cell <NUM> is charged or discharged. Alternatively, the number of charging/discharging times of the battery cell <NUM> may be used as the driving time. Alternatively, the driving time data L may indicate a cumulative driving time of the battery module <NUM>. The driving time data L may be data for each battery cell <NUM>, or may be common data with respect to the battery cells <NUM> in the battery module <NUM>.

<FIG> shows an example of the transmission data. In the example of <FIG>, one piece of transmission data includes data related to one battery module <NUM>. In another example, one piece of transmission data may include data related to the plurality of battery modules <NUM>.

The transmission data may include identification data. The identification data includes at least one of the module identification data Mo or the cell identification data Ce.

The transmission data may include analysis result data A. The analysis result data A is data related to the capacity of each of the battery cells <NUM>, for example. In another example, the analysis result data A is data indicating at least one of the maximum value, minimum value, or average value of the capacities of the one or more battery cells <NUM> included in the battery module <NUM>.

The transmission data may include control data Co. The control data Co is data used for controlling charging and discharging of the one or more battery cells <NUM> included in the battery module <NUM>. The control data Co may designate at least one of a charge amount, a discharge amount, a charge timing, a discharge timing, a charge rate, or a discharge rate of each of the battery cells <NUM>. The data analysis unit <NUM> may generate the control data Co based on the analysis result on the capacity of each of the battery cells <NUM>. For example, the data analysis unit <NUM> generates control data Co for reducing capacity variations among the one or more battery cells <NUM> in the battery module <NUM>. The data analysis unit <NUM> may generate the control data Co when a difference between a maximum value and minimum value of remaining capacities of the plurality of battery cells <NUM> included in the battery module <NUM> becomes equal to or larger than a predetermined threshold value. Accordingly, it is possible to suppress a situation where capacity variations among the battery cells <NUM> become too large.

The transmission data may include replacement time data R. The data analysis unit <NUM> may calculate a time to replace each of the battery cells <NUM> based on the analysis result on the capacity of each of the battery cells <NUM>. As an example, the data analysis unit <NUM> may calculate a deterioration rate of each of the battery cells <NUM> based on a history of measurement data recorded in the analysis data recording unit <NUM>, and estimate a replacement time based on the deterioration rate. The deterioration of the battery cell <NUM> can be calculated from deterioration of, for example, the full charge capacity, the interpolar voltage, the output current, or the like. The data analysis unit <NUM> may calculate a time at which the characteristics of the battery cell <NUM> fall below a predetermined reference value, as the replacement time of the battery cell <NUM>. The replacement time data R may be data for each battery cell <NUM>. In another example, the replacement time data R may be data for each battery module <NUM>. In this case, of the replacement times of the battery cells <NUM> included in the battery module <NUM>, the data analysis unit <NUM> may use the earliest replacement time as the replacement time of the battery module <NUM>.

The transmission data may include failure data F. The data analysis unit <NUM> may judge whether a failure has occurred in each of the battery cells <NUM> based on the analysis result on the capacity of each of the battery cells <NUM>. As an example, the data analysis unit <NUM> judges whether a failure has occurred in each of the battery cells <NUM> based on a temporal change of the characteristics such as the full charge capacity, of each of the battery cells <NUM>. The data analysis unit <NUM> may judge that a failure has occurred in the battery cell <NUM> when a difference between a characteristics value calculated last time and a characteristics value calculated this time exceeds a predetermined reference value. The failure data F may be data for each battery cell <NUM>. In another example, the failure data F may be data for each battery module <NUM>. In this case, the data analysis unit <NUM> may judge that a failure has occurred in the battery module <NUM> when a failure occurs in any of the battery cells <NUM> included in the battery module <NUM>.

The transmission data may include at least one of the analysis result data, the control data, the replacement time data, or the failure data. The transmission data may also include data other than these.

<FIG> illustrates variations in the remaining capacities of the battery cells <NUM> included in the battery module <NUM>. <FIG> will be described using three battery cells <NUM>-<NUM>, <NUM>-<NUM>, and <NUM>-<NUM>, but the number of battery cells <NUM> included in the battery module <NUM> is not limited to three. In <FIG>, each of the battery cells <NUM> is rectangular. An upper end max of the rectangle indicates an upper limit value of the remaining capacity (i.e., full charge capacity) of the battery cell <NUM>, and a lower end min indicates a lower limit value of the remaining capacity of the battery cell <NUM>. The battery cell <NUM> is charged and discharged between the upper limit max and the lower limit min for preventing overcharge and over-discharge from occurring. In <FIG>, the remaining capacity of each of the battery cells <NUM> is hatched with oblique lines.

As shown in the diagram of <FIG> showing a state before processing, variations may be caused in the remaining capacities of the battery cells <NUM> included in the battery module <NUM>. For example, variations are caused in the remaining capacities of the battery cells <NUM> when natural discharge rates of the battery cells <NUM> differ.

The plurality of battery cells <NUM> of the present example are charged simultaneously. Therefore, when variations are caused in the remaining capacities, charging only by an amount corresponding to the battery cell <NUM> having a smallest available capacity is carried out in each of the battery cells <NUM>, and thus not all the battery cells <NUM> can be charged to the upper limit max. Similarly, when the plurality of battery cells <NUM> are simultaneously discharged with respect to loads thereof, each of the battery cells <NUM> can be discharged only by an amount corresponding to the battery cell <NUM> having the smallest remaining capacity, and thus not all the battery cells <NUM> can be discharged to the lower limit min. Therefore, effective capacities of the plurality of battery cells <NUM> decrease according to a variation amount of the remaining capacities.

The analysis device <NUM> may analyze the remaining capacity of each of the battery cells <NUM>. The battery management device <NUM> may charge and discharge each of the battery cells <NUM> and adjust a cell balance so that the variations in the remaining capacities of the battery cells <NUM> are reduced. Note that in the present example, the battery cells <NUM> are discharged to adjust a cell balance. For example, in <FIG>, the battery cells <NUM> having relatively large remaining capacities are discharged. In another example, the battery cells <NUM> may be charged to adjust the cell balance. For example, the battery cells <NUM> having relatively small remaining capacities may be charged. Alternatively, the cell balance may be adjusted by combining the discharge and charge described above. The diagram of <FIG> showing a state after processing shows an effective capacity of the battery cells <NUM> after the cell balance is adjusted. The effective capacity increases by reducing the variations in the remaining capacities of the battery cells <NUM>. The data analysis unit <NUM> may estimate an increase amount of the effective capacity by performing cell balance processing. The data transmission unit <NUM> may transmit transmission data indicating the estimated increase amount of the effective capacity to the battery management device <NUM>.

<FIG> shows another configuration example of the analysis device <NUM>. The analysis device <NUM> of the present example accurately analyzes the capacity of each of the battery cells <NUM>. As the analysis accuracy of the data analysis unit <NUM> regarding the remaining capacity becomes higher, the cell balance adjustment can be executed with higher accuracy, and it becomes easier to increase the effective capacity. The analysis device <NUM> of the present example further includes a reference characteristics recording unit <NUM> with respect to the example shown in <FIG>. Other configurations are similar to those of the example described with reference to <FIG>.

The reference characteristics recording unit <NUM> records predetermined reference characteristics. The data analysis unit <NUM> analyzes the capacity of the battery cell <NUM> based on the characteristics calculated from the measurement data and the reference characteristics.

<FIG> illustrates an example of the measurement data included in the analysis data. The measurement unit <NUM> of the present example measures capacitance-voltage characteristics that indicate a relationship between the interpolar voltage, which is obtained during charging or discharging of each of the battery cells <NUM>, and an estimated remaining capacity, and generates measurement data. The measurement unit <NUM> may measure the capacitance-voltage characteristics during an actual operation of the battery module <NUM>. For example, during an actual operation means a state where the battery module <NUM> supplies electrical power to a load or a state where surplus electrical power of a power generation device is supplied to the battery module <NUM>. The measurement unit <NUM> may calculate the remaining capacity of each of the battery cells <NUM> from an integrated amount of a current output from the battery module <NUM> and a current supplied to the battery module <NUM>. The remaining capacity of the battery cell <NUM> decreases by an amount corresponding to the amount of current output from the battery module <NUM>, and the remaining capacity of the battery cell <NUM> increases by an amount corresponding to the amount of current charged to the battery module <NUM>.

The measurement unit <NUM> of the present example measures the capacitance-voltage characteristics within a predetermined measurement range of an estimated remaining capacity Q. The measurement range is a part of a range of the estimated remaining capacity from the lower limit min to the upper limit max. It is preferable for the measurement range not to include the lower limit min and upper limit max of the estimated remaining capacity. Accordingly, the measurement unit <NUM> can measure the capacitance-voltage characteristics while avoiding a situation where the battery cells <NUM> are close to an overcharged state or an over-discharged state. A size of the measurement range may be half or less or <NUM>/<NUM> or less of the size of the range from the lower limit min to the upper limit max. By reducing the size of the measurement range, the capacitance-voltage characteristics can be acquired in a short time, and the capacitance-voltage characteristics are acquired easily even during an actual operation of the battery module <NUM>. Further, by reducing the size of the measurement range, it becomes easy to measure, even in a state where there are variations in the remaining capacities of the plurality of battery cells <NUM>, the capacitance-voltage characteristics without causing overcharging or over-discharging of each of the battery cells <NUM>.

<FIG> shows an example of the reference characteristics recorded by the reference characteristics recording unit <NUM>. The reference characteristics correspond to characteristics obtained by differentiating the capacitance-voltage characteristics of the battery cell <NUM> by the remaining capacity. The reference characteristics of the battery cell <NUM> can be determined in advance based on an electrode material of the battery cell <NUM>, or based on a manufacturer or model of the battery cell <NUM> or the battery module <NUM>. The reference characteristics recording unit <NUM> may record a plurality of types of reference characteristics in accordance with a plurality of types of electrode materials. It is preferable for the data analysis unit <NUM> to analyze the battery cell <NUM> using the reference characteristics corresponding to the electrode material of the battery cell <NUM> as the analysis target. The data acquisition unit <NUM> may acquire analysis data indicating the electrode material of the battery cell <NUM>. Further, the analysis data recording unit <NUM> may record information indicating the electrode material of the battery cell <NUM> in association with at least one of the battery module <NUM> or the battery cell <NUM>.

For example, when the battery cell <NUM> is a lithium battery, lithium ions move between the positive electrode and the negative electrode during charging and discharging. Lithium ions are inserted into each electrode active material (also referred to as reduction) or lithium ions are desorbed (also referred to as oxidization), with the result that a crystal structure of the electrode active material changes. This change in the crystal structure is called "phase transition", which is a phenomenon that occurs near a potential unique to the electrode active material defined electrochemically. By the phase transition phenomenon, peaks appear at predetermined positions in the reference characteristics.

As described above, it is possible to determine the capacitance-voltage characteristics of the battery cell <NUM> according to the type of the electrode active material, and also determine the reference characteristics as derivation characteristics thereof. The reference characteristics may be acquired by premeasuring characteristics of one or more battery cells as a reference. Alternatively, the reference characteristics may be acquired in advance by a simulation. A method of acquiring the reference characteristics may be similar to that described in Patent Document <NUM>.

<FIG> illustrates a method of calculating the remaining capacity of the battery cell <NUM> using the reference characteristics and the derivation characteristics. In <FIG>, the derivation characteristics in the measurement range shown in <FIG> are indicated by a solid line, and the reference characteristics are indicated by dashes. The data analysis unit <NUM> of the present example performs a parallel shift of the derivation characteristics to a position at which an error between the derivation characteristics and the reference characteristics becomes minimum. The data analysis unit <NUM> may determine the position by the method of least squares. An amount by which the derivation characteristics are moved in an axial direction of the remaining capacity Q corresponds to an error between the estimated remaining capacity of the battery cell <NUM> described in <FIG> and the actual remaining capacity. The data analysis unit <NUM> may calculate the actual remaining capacity of the battery cell <NUM> from the error and a current estimated remaining capacity of the battery cell <NUM>. The data analysis unit <NUM> may calculate the actual remaining capacity of the battery cell <NUM> by a method similar to the method disclosed in Patent Document <NUM>.

As shown in <FIG>, each reference characteristics may include a reference feature point. The reference feature point is a point that should be included in the derivation characteristics for performing fitting of the reference characteristics and the derivation characteristics with high accuracy. The reference feature point may be a point at which a fluctuation corresponding to a measurement condition such as a temperature, is smaller than that of other points. The reference feature point may be arranged in a slope portion between the peaks of the reference characteristics. The reference feature point may be a point at which a local minimum value of the reference characteristics is obtained. The reference feature point may be an apex of a peak of the reference characteristics. A plurality of reference feature points may be set in the reference characteristics. The reference characteristics recording unit <NUM> may record a value of the remaining capacity at the reference feature point, for each reference characteristics.

The measurement unit <NUM> may measure the characteristics of the battery cell <NUM> within a measurement range including any of the reference feature points (i.e., range of estimated remaining capacity). The position of each reference feature point may be notified to the battery management device <NUM> from the analysis device <NUM>. Further, the analysis device <NUM> may notify the battery management device <NUM> of the measurement range including any of the reference feature points. By acquiring the measurement data within the measurement range, a measurement feature point corresponding to the reference feature point is included in the derivation characteristics of the measurement data.

The data analysis unit <NUM> may analyze the capacity of the battery cell <NUM> based on the measurement feature point in the derivation characteristics of the battery cell <NUM> and the reference feature point in the reference characteristics. As described above, the data analysis unit <NUM> may perform a parallel shift of the derivation characteristics such that the position of the measurement feature point and the position of the reference feature point match.

Although the remaining capacity of the battery cell <NUM> has been analyzed in the present example, the data analysis unit <NUM> may also analyze a full charge capacity of the battery cell <NUM>. In this case, the data analysis unit <NUM> may use the derivation characteristics obtained by differentiating the capacitance-voltage characteristics by a voltage. Further, the reference characteristics recording unit <NUM> may record the reference characteristics corresponding to the derivation characteristics. The data analysis unit <NUM> may adjust at least one of the position or amplitude of the reference characteristics so that an error with respect to the derivation characteristics becomes minimum. By integrating the adjusted reference characteristics within a predetermined range of a working voltage, the full charge capacity of the battery cell <NUM> can be calculated. The data analysis unit <NUM> may calculate the full charge capacity of the battery cell <NUM> by a method similar to the method disclosed in Patent Document <NUM>. The data analysis unit <NUM> may calculate a ratio of the remaining capacity to the full charge capacity (also referred to as SOC).

Note that when the analysis data includes temperature data indicating a temperature of the battery cell <NUM> obtained at a time of measuring the capacitance-voltage characteristics, the data analysis unit <NUM> may correct the analysis that uses the derivation characteristics, based on the temperature of the battery cell <NUM>. The capacitance-voltage characteristics of the battery cell <NUM> may fluctuate depending on the temperature of the battery cell <NUM>. The data analysis unit <NUM> may correct a characteristics fluctuation due to the temperature of the battery cell <NUM> and analyze the characteristics of the battery cell <NUM>. Specifically, the data analysis unit <NUM> may correct at least one of the derivation characteristics or the reference characteristics using the temperature. According to the temperature, the data analysis unit <NUM> may shift the derivation characteristics or the reference characteristics in an axial direction of the remaining capacity. The data analysis unit <NUM> may correct an amplitude of the derivation characteristics or the reference characteristics according to the temperature. Correction information indicating the way to correct each characteristics according to the temperature of the battery cell <NUM> may be preset in the data analysis unit <NUM>. The correction information can be generated by premeasuring how the capacitance-voltage characteristics fluctuate according to the temperature fluctuation.

The data analysis unit <NUM> can analyze the capacity of the battery cell <NUM> highly accurately by the method described with reference to <FIG>. Note that the analysis by the data analysis unit <NUM> is not limited to the content described with reference to <FIG>. The data analysis unit <NUM> may analyze information related to the capacity of the battery cell <NUM> using a well-known technique. For example, the data analysis unit <NUM> can calculate the remaining capacity based on the interpolar voltage of the battery cell <NUM>. A relationship between the interpolar voltage and the remaining capacity may be provided in advance to the data analysis unit <NUM>. The data analysis unit <NUM> may estimate the remaining capacity of the battery cell <NUM> by integrating the output current and charging current of the battery cell <NUM>.

<FIG> illustrates processing for reducing variations in the remaining capacities of the plurality of battery cells <NUM> included in the battery module <NUM>. The present example will be described using three battery cells <NUM>, but the number of battery cells <NUM> is not limited to three. As described above, the data analysis unit <NUM> may generate transmission data for charging and discharging the battery cells <NUM>. The charging and discharging of the battery cells <NUM> may be performed by the battery management device <NUM> based on control data Co included in the transmission data, or may be performed by the battery management device <NUM> based on analysis result data A included in the transmission data.

An initial step S1001 indicates a state where the remaining capacities of the battery cells <NUM> vary. Note that in <FIG>, the remaining capacities are hatched with oblique lines similar to <FIG>. Next, in a first measurement step S1002, all the battery cells <NUM> may be discharged by the same amount. While discharging the battery cells <NUM>, the measurement unit <NUM> measures characteristics of each of the battery cells <NUM>, such as the interpolar voltage and the discharging current. Next, in a second measurement step S1003, all the battery cells <NUM> may be charged by the same amount. While charging the battery cells <NUM>, the measurement unit <NUM> measures characteristics of each of the battery cells <NUM>, such as the interpolar voltage and the charging current. By the processing of S1002 and S1003, the measurement unit <NUM> can measure the capacitance-voltage characteristics of each of the battery cells <NUM>. The measurement unit <NUM> may calculate an estimated remaining capacity of each of the battery cells <NUM> by sequentially integrating the discharging current or the charging current.

The measurement unit <NUM> may also measure the capacitance-voltage characteristics during an actual operation of the battery module <NUM> in place of the processing of S1002 and S1003. That is, the measurement unit <NUM> may also measure the voltages and currents of the battery cells <NUM> while a current is supplied from the battery module <NUM> to a load or while surplus electrical power of the power generation device is being charged to the battery module <NUM>.

Next, in a discharging step S1004, at least one of the battery cells <NUM> in which the remaining capacity is not the smallest is discharged, to reduce a difference in the remaining capacities with respect to the battery cell <NUM> having the smallest remaining capacity. In S1004, all the battery cells <NUM> except for the battery cell <NUM> having the smallest remaining capacity may be discharged by the same amount. In the example of <FIG>, the remaining capacity of the battery cell <NUM>-<NUM> is the smallest. In S1004, the battery cells <NUM>-<NUM> and <NUM>-<NUM> are discharged. In the discharging step S1004, the battery cells <NUM>-<NUM> and <NUM>-<NUM> may be discharged such that, out of the battery cells <NUM>-<NUM> and <NUM>-<NUM> except for the battery cell <NUM>-<NUM>, the remaining capacity of the battery cell <NUM>-<NUM> having the smallest remaining capacity becomes equal to the remaining capacity of the battery cell <NUM>-<NUM>.

Next, in a discharging step S1005, processing similar to that of the discharging step S1004 is repeated. That is, at least one of the battery cells <NUM> in which the remaining capacity is not the smallest is discharged so as to reduce a difference in the remaining capacities with respect to the battery cell <NUM> having the smallest remaining capacity. In the present example, the remaining capacities of the battery cells <NUM>-<NUM> and <NUM>-<NUM> are the smallest. Therefore, in the present example, the battery cell <NUM>-<NUM> is discharged. Also in S1005, the battery cell <NUM>-<NUM> may be discharged such that the remaining capacity of the battery cell <NUM>-<NUM> becomes equal to the smallest remaining capacity.

By repeating the discharging step described in S1004 or S1005, the remaining capacities of all the battery cells <NUM> can be made equal to one another. Accordingly, the effective capacity of the battery module <NUM> can be increased.

In S1002 to S1005, it is preferable to control charging and discharging of the battery cells <NUM> so that the remaining capacity of any of the battery cells <NUM> does not become the upper limit max and the lower limit min of each of the battery cells <NUM>. Accordingly, it is possible to suppress a situation where the battery cells <NUM> are over-discharged or overcharged, and suppress deterioration of the battery cells <NUM> in the processing described with reference to <FIG>. In a case where the battery cell <NUM> is a lithium ion battery in particular, deterioration tends to be promoted when left in a state where the remaining capacity is close to the upper limit max. Further, when left in a state where the remaining capacity is close to the lower limit min, natural discharge tends to be promoted so as to cause over-discharge, thereby promoting deterioration. Therefore, when the battery cell <NUM> is a lithium ion battery, the effect of deterioration suppression by the processing described with reference to <FIG> may become prominent.

Note that when the accuracy in analyzing the capacity of the battery cell <NUM> is low, each of the battery cells <NUM> may be set to a full charge state for matching the remaining capacities of the battery cells <NUM>. In contrast, by using the method described with reference to <FIG>, the capacity of each of the battery cells <NUM> can be analyzed accurately. Therefore, as described with reference to <FIG>, the cell balance can be adjusted without setting the battery cells <NUM> to a full charge state. Further, since the measurement only needs to be performed within a partial measurement range in the method described with reference to <FIG>, it becomes easy to perform control such that the remaining capacity of the battery cell <NUM> does not become the upper limit max or the lower limit min. Furthermore, since each of the battery cells <NUM> is not set to the full charge state according to the method described with reference to <FIG>, the remaining capacities can be balanced in a short processing time. Therefore, an effect on the actual operation of the battery module <NUM> is small. By executing the processing of <FIG> at a high frequency, the effective capacity of the battery module <NUM> can be kept high.

<FIG> shows an example of the capacitance-voltage characteristics during discharging of the battery cell <NUM>. Note that the capacitance-voltage characteristics shown in <FIG> are an example of the capacitance-voltage characteristics during charging of the battery cell <NUM>. The capacitance-voltage characteristics during discharging are capacitance-voltage characteristics that have been measured while lowering the remaining capacity of the battery cell <NUM>, and the capacitance-voltage characteristics during charging are capacitance-voltage characteristics that have been measured while raising the remaining capacity of the battery cell <NUM>. As shown in <FIG> and <FIG>, the capacitance-voltage characteristics of the battery cell <NUM> may differ between the time of charging and the time of discharging. The fact that the capacitance-voltage characteristics may differ between the time of charging and the time of discharging of the battery cell <NUM> has been confirmed experimentally.

<FIG> shows an example of the reference characteristics during discharging of the battery cell <NUM>. Similar to the capacitance-voltage characteristics, also the reference characteristics obtained by differentiating the capacitance-voltage characteristics may differ between the time of charging and the time of discharging of the battery cell <NUM>. The reference characteristics recording unit <NUM> may record at least one of the reference characteristics obtained when charging the battery cell <NUM> or the reference characteristics obtained when discharging the battery cell <NUM>. In the present example, the reference characteristics recording unit <NUM> records both the reference characteristics during charging and the reference characteristics during discharging.

The data analysis unit <NUM> may select, based on which of data obtained during charging of the battery cell <NUM> or data obtained during discharging the measurement data Me of the battery cell <NUM> is, the reference characteristics to be compared with the derivation characteristics calculated from the measurement data Me. That is, when the measurement data Me is measurement data obtained during charging, the data analysis unit <NUM> selects the reference characteristics during charging. Alternatively, when the measurement data Me is measurement data obtained during discharging, the data analysis unit <NUM> selects the reference characteristics during discharging. It is preferable for the analysis data to include data that indicates which of the measurement data obtained during charging or the measurement data obtained during discharging the measurement data Me is.

<FIG> illustrates an overview of the charging and discharging of the battery cell <NUM>. In <FIG>, a case where the battery cell <NUM> is a lithium ion battery will be described. A negative electrode <NUM> of the battery cell <NUM> includes a plurality of graphite layers <NUM>. By charging and discharging the battery cell <NUM>, lithium ions <NUM> are inserted between or desorbed from the graphite layers <NUM>. A state of the negative electrode <NUM> corresponding to a density at which the lithium ions <NUM> are inserted between the graphite layers <NUM> is referred to as a stage. The capacitance-voltage characteristics change according to the stage of the negative electrode <NUM>. One of the reasons why the capacitance-voltage characteristics of the battery cell <NUM> differ between the time of charging and the time of discharging is probably because operations of the lithium ions <NUM> differ between the time of insertion into the graphite layers <NUM> and the time of desorption from the graphite layers <NUM>.

<FIG> illustrates another example of the cell balance processing. Also in the present example, the data analysis unit <NUM> may generate transmission data for charging and discharging the battery cell <NUM>, similar to the example of <FIG>. The charging and discharging of the battery cells <NUM> may be performed by the battery management device <NUM> based on the control data Co included in the transmission data, or may be performed by the battery management device <NUM> based on the analysis result data A included in the transmission data.

An initial step S1501 shows a state where the remaining capacities of the battery cells <NUM> vary. Next, in a charging step S1502, each of the battery cells <NUM> is charged until the battery cell <NUM>-<NUM> having a largest remaining capacity is fully charged.

Next, in a discharging step S1503, the battery cell <NUM>-<NUM> that has been fully charged is discharged. In S1503, the battery cell <NUM>-<NUM> is discharged until the remaining capacity of the battery cell <NUM>-<NUM>, which has the largest remaining capacity out of the battery cells <NUM> excluding the battery cell <NUM>-<NUM>, matches the remaining capacity of the battery cell <NUM>-<NUM>.

Next, in a charging step S1504, each of the battery cells <NUM> is charged until the battery cells <NUM>-<NUM> and <NUM>-<NUM> having the largest remaining capacities are fully charged.

Next, in a discharging step S1505, the battery cells <NUM>-<NUM> and <NUM>-<NUM> that have been fully charged are discharged. In S1505, the battery cells <NUM>-<NUM> and <NUM>-<NUM> are discharged until the remaining capacities of the battery cells <NUM>-<NUM> and <NUM>-<NUM> and the remaining capacity of the battery cell <NUM>-<NUM>, which has the largest remaining capacity out of the rest of the battery cells <NUM>, match. As described above, by repeating the charging step and the discharging step, the remaining capacities of all the battery cells <NUM> can be made equal to one another. Accordingly, the effective capacity of the battery module <NUM> can be increased.

Note that also in the example of <FIG>, the data analysis unit <NUM> may analyze the capacity of the battery cell <NUM> by the method described with reference to <FIG>, or may use other methods. The data analysis unit <NUM> may calculate the remaining capacity based on the interpolar voltage of the battery cell <NUM>. The data analysis unit <NUM> may estimate the remaining capacity of the battery cell <NUM> by integrating the output current and charging current of the battery cell <NUM>.

<FIG> illustrates an overview of the battery module <NUM>. The battery module <NUM> of the present example includes a positive terminal <NUM>, a negative terminal <NUM>, and the plurality of battery cells <NUM> connect in series between both terminals. The battery module <NUM> further includes, with respect to each of the battery cells <NUM>, a discharging switch <NUM>, a discharge resistance <NUM>, and a voltmeter <NUM>. The discharging switch <NUM> switches whether to connect a positive electrode and a negative electrode of the battery cell <NUM> via the discharge resistance <NUM>. By setting the discharging switch <NUM> in an ON state, the corresponding battery cell <NUM> can be discharged. The voltmeter <NUM> measures the interpolar voltage of the corresponding battery cell <NUM>. The voltmeter <NUM> functions as a part of the measurement unit <NUM>.

The battery module <NUM> may further include an ammeter <NUM> provided in series with respect to the plurality of battery cells <NUM>. The ammeter <NUM> measures a current flowing through the plurality of battery cells <NUM>. The ammeter <NUM> functions as a part of the measurement unit <NUM>.

In the battery module <NUM> of the present example, the individual battery cells <NUM> can be selected for discharging. Further, when charging the plurality of battery cells <NUM>, the battery management device <NUM> connects a charging power source to the positive terminal <NUM> and the negative terminal <NUM>. Therefore, the plurality of battery cells <NUM> are charged at the same time. According to the method described with reference to <FIG> or <FIG>, the variations of the remaining capacities in the battery module <NUM> having the configuration shown in <FIG> can be reduced easily.

<FIG> is a flowchart showing an operation example of the analysis device <NUM>. The analysis device <NUM> of the present example generates correction data for correcting the remaining capacity of each of the battery cells <NUM> based on the analysis data, and transmits it to the battery management device <NUM>. Other operations are similar to those of the examples described with reference to <FIG>.

First, in a measurement start step S1101, the data transmission unit <NUM> causes the battery management device <NUM> to start a measurement of the characteristics of the battery cells <NUM>. The data transmission unit <NUM> may transmit transmission data that becomes a trigger to start the measurement via the network <NUM>. The data transmission unit <NUM> may transmit transmission data that designates the measurement range shown in <FIG>. Next, in a transfer request step S1102, the data transmission unit <NUM> requests the battery management device <NUM> to transfer analysis data via the network <NUM>.

Next, in a data acquisition step S1103, the data acquisition unit <NUM> acquires analysis data from the analysis data transmission unit <NUM> via the network <NUM>. Next, in a data analysis step S1104, the data analysis unit <NUM> analyzes characteristics related to the charging capacity of at least one of the battery cells <NUM> based on the analysis data acquired in the data acquisition step S1103. The data analysis unit <NUM> of the present example may calculate an error between the estimated remaining capacity of the battery cell <NUM> estimated by the measurement unit <NUM> and the remaining capacity calculated by the analysis. Next, in a result transmission step S1105, the data transmission unit <NUM> transmits transmission data corresponding to the analysis result obtained in the data analysis step S1104 to the battery management device <NUM> via the network <NUM>. The transmission data of the present example includes correction data for correcting the estimated remaining capacity.

<FIG> is a flowchart showing an operation example of the battery management device <NUM>, the measurement unit <NUM>, and the analysis data transmission unit <NUM>. The battery management device <NUM> of the present example corrects the estimated remaining capacity of each of the battery cells <NUM> based on an analysis result obtained by the analysis device <NUM>. Accordingly, accuracy of the estimated remaining capacity managed by the battery management device <NUM> can be improved. Other operations are similar to those of the examples described with reference to <FIG>.

First, in the analysis system <NUM> of the present example, in a measurement step S1201, the measurement unit <NUM> generates measurement data obtained by measuring characteristics related to charging and discharging of one or more battery cells <NUM> included in the battery module <NUM>. The measurement unit <NUM> may measure the characteristics of each of the battery cells <NUM> so as to include the measurement range designated by the transmission data. The battery management device <NUM> may cause the measurement unit <NUM> to start the measurement according to the trigger received from the analysis device <NUM> in the measurement start step S1101 of <FIG>. The measurement step S1201 corresponds to S1002 and S1003 in <FIG>.

When the battery cells <NUM> are charged and discharged in order to measure the characteristics of the battery cells <NUM>, the measurement unit <NUM> integrates current values obtained during charging and discharging of the battery cells <NUM> (S1202). Further, the measurement unit <NUM> acquires an integrated value of the current values at each timing within a predetermined period (S1203). The measurement unit <NUM> calculates an estimated value of the remaining capacity at each timing based on the acquired integrated value (S1204). Accordingly, the capacitance-voltage characteristics of the battery cells <NUM> in the predetermined measurement range can be acquired as shown in <FIG>.

Next, in a first judgment step S1205, the battery management device <NUM> judges whether a transfer request for analysis data has been received from the analysis device <NUM>. When the transfer request is received, the battery management device <NUM> causes the analysis data transmission unit <NUM> to transmit the analysis data (S1206). When the transfer request is not received, the battery management device <NUM> performs next processing without performing the processing of S1206.

Next, in a second judgment step S1207, the battery management device <NUM> judges whether correction data for correcting the estimated remaining capacity has been received from the analysis device <NUM>. When the correction data is received, the battery management device <NUM> corrects the estimated remaining capacity (S1208). When the correction data is not received, the battery management device <NUM> repeats the processing from S1201.

<FIG> shows another example of the analysis content by the data analysis unit <NUM>. The data analysis unit <NUM> of the present example calculates a deterioration rate of the battery cell <NUM> from the derivation characteristics of the battery cell <NUM>. The data analysis unit <NUM> may calculate the deterioration rate of the battery cell <NUM> from a change of the full charge capacity of the battery cell <NUM>. The data analysis unit <NUM> may calculate the number of charging/discharging times of the battery cell <NUM> from a usage history of the battery cell <NUM>, and calculate the deterioration rate based on a deterioration amount of the full charge capacity with respect to the number of charging/discharging times. The data analysis unit <NUM> may use, as the number of charging times of the battery cell <NUM>, a quotient obtained by dividing the integrated value of the charging current of the battery cell <NUM> within a usage period by a predetermined reference value. The data analysis unit <NUM> may use, as the number of discharging times of the battery cell <NUM>, a quotient obtained by dividing the integrated value of the discharging current of the battery cell <NUM> within the usage period by a predetermined reference value. As these reference values, a rating capacity of the battery cell <NUM> may be used. The data analysis unit <NUM> may use a sum of the number of charging times and the number of discharging times as the number of charging/discharging times.

<FIG> shows a graph in which a horizontal axis represents the number of charging/discharging times, and a vertical axis represents the full charge capacity. The data analysis unit <NUM> may calculate a temporal change of the full charge capacity of each of the battery cells <NUM> based on the time series measurement data recorded by the analysis data recording unit <NUM>. In this case, the measurement data may include respective integrated values of the charging current and the discharging current during a period from a start of the use of the battery cell <NUM> to a timing of measuring the characteristics of the battery cell <NUM>.

The data analysis unit <NUM> may calculate the deterioration rate of the battery cell <NUM> based on a change amount of the full charge capacity from a predetermined start point to a current time point. The start point may be set at any timing from the time point the battery cell <NUM> is started to be used to the current time point. The deterioration rate of the present example is a deterioration amount of the full charge capacity per unit number of charging/discharging times.

The data analysis unit <NUM> may also estimate the deterioration rate of the full charge capacity from the current time point onward, from an actual measurement value of the temporal change of the full charge capacity. The data analysis unit <NUM> may use the deterioration rate from a predetermined start point to the current time point, as the deterioration rate from the current time point onward.

In another example, the data analysis unit <NUM> may estimate the deterioration rate from the current time point onward from the value of the full charge capacity at the current time point. A relationship between the value of the full charge capacity and the deterioration rate from the current time point onward may be provided in advance to the data analysis unit <NUM>. The relationship may be a designed value set by a manufacturer of the battery cells <NUM>, or may be a relationship obtained statistically from performance of the same type of battery cells <NUM>.

The data analysis unit <NUM> may generate replacement time data indicating a time to replace the battery cell <NUM> based on the analysis result on the analysis data. For example, the data analysis unit <NUM> estimates a time at which the full charge capacity falls below a predetermined reference value Qref based on the estimated value of the deterioration rate. The time may be expressed by a time that has elapsed since the current time point (for example, month, day, or time), or may be expressed by the number of charging/discharging times. The data analysis unit <NUM> may calculate the number of times charging and discharging have been performed per unit time, from the usage history of the battery cell <NUM>. The data analysis unit <NUM> may calculate an elapsed time corresponding to the replacement time from the calculated relationship between the time and the number of charging/discharging times. The data analysis unit <NUM> may also generate, when the full charge capacity at the current time point falls below the predetermined reference value Qref, replacement time data indicating that a period before reaching the replacement time is <NUM> (i.e., replacement should be performed at current time point).

<FIG> shows another example of the analysis content by the data analysis unit <NUM>. Based on a deviation amount of the charging capacities between two or more battery cells <NUM>, that is calculated from the derivation characteristics of the two or more battery cells <NUM>, the data analysis unit <NUM> of the present example calculates a deviation rate of the charging capacities between the two or more battery cells <NUM>. The deviation amount may be used as the deterioration amount of the two or more battery cells <NUM>. The charging capacity may be the remaining capacity at the time of starting the measurement of the characteristics of the battery cells <NUM> as shown in the initial step S1001 of <FIG> or the initial step S1501 of <FIG>. The charging capacity may be the full charge capacity of the battery cell <NUM>. Similar to the calculation of the deterioration rate, the data analysis unit <NUM> may calculate the number of charging/discharging times of the battery cell <NUM> from the usage history of the battery cell <NUM> recorded by the analysis data recording unit <NUM>, and calculate the deviation rate based on a change of the deviation amount with respect to the number of charging/discharging times.

<FIG> shows a graph in which a horizontal axis represents the number of charging/discharging times, and a vertical axis represents a deviation amount of the charging capacities. The data analysis unit <NUM> may calculate a temporal change of the deviation amount of the charging capacities based on the time series measurement data recorded by the analysis data recording unit <NUM>. The data analysis unit <NUM> may calculate a deviation rate of the charging capacities between the battery cells <NUM> based on a change of the deviation amount from a predetermined start point to the current time point.

The data analysis unit <NUM> may estimate the deviation rate from the current time point onward from an actual measurement value of the temporal change of the deviation amount. The data analysis unit <NUM> may use the deviation rate from a predetermined start point to the current time point, as the deviation rate from the current time point onward.

In another example, the data analysis unit <NUM> may estimate the deviation rate from the current time point onward from the value of the deviation amount at the current time point. A relationship between the value of the deviation amount and the deviation rate from the current time point onward may be provided in advance to the data analysis unit <NUM>. The relationship may be a designed value set by a manufacturer of the battery cells <NUM>, or may be a relationship obtained statistically from performance of the same type of battery cells <NUM>.

<FIG> shows a transition example of the effective capacity of the battery module <NUM>. A maximum value of the effective capacity of the battery module <NUM> corresponds to a sum of the full charge capacities of the battery cells <NUM>. Note that as described with reference to <FIG>, when the remaining capacities of the respective battery cells <NUM> vary, the effective capacity of the battery module <NUM> becomes smaller than a maximum value thereof. In <FIG>, the maximum value of the effective capacity is indicated by dashes, and an actual effective capacity is indicated by a solid line. In the present example, the maximum value of the effective capacity gradually decreases due to temporal deterioration of each of the battery cells <NUM>.

When the variations in the remaining capacities among the battery cells <NUM> increase due to variations in natural discharge amounts or the like, the effective capacity of the battery module <NUM> gradually decreases. In the analysis system <NUM> of the present example, the cell balance processing on the remaining capacities of the battery cells <NUM>, that has been described with reference to <FIG>, is executed at predetermined time intervals I1. Therefore, the effective capacity of the battery module <NUM> recovers to a value close to the maximum value at each time interval I1.

By shortening the time intervals I1, an adjustment amount of the effective capacity in one cell balance processing can be made small. Therefore, it is possible to shorten a time required for the cell balance processing and thus shorten a time during which the battery module <NUM> cannot be actually operated.

The data analysis unit <NUM> may adjust the time intervals I based on the deviation rate of the charging capacities of two or more battery cells <NUM>. The data analysis unit <NUM> may shorten the time intervals I when a difference between the calculated deviation rate and a predetermined designed value becomes large. The data analysis unit <NUM> may shorten the time intervals I when a tendency of the deviation among the charging capacities of the battery cells <NUM> changes. The change of the tendency of the deviation is, for example, a case where a deviation of the battery cells <NUM> different from the past becomes large. The data analysis unit <NUM> may set the time intervals I to become shorter as the deviation rate increases. Accordingly, an increase of the adjustment amount in one cell balance processing can be suppressed. In the example of <FIG>, the data analysis unit <NUM> adjusts the time intervals to I2.

The data analysis unit <NUM> calculates measurement intervals to measure data related to the charging and discharging of two or more battery cells <NUM> according to the time intervals, so that the cell balance processing can be executed at the time intervals. As an example, the measurement interval is equal to the time interval. The data transmission unit <NUM> transmits transmission data corresponding to the measurement interval. The data transmission unit <NUM> may transmit transmission data that becomes a trigger for the measurement unit <NUM> to measure the characteristics of the battery cell <NUM> at timings corresponding to the measurement intervals. In another example, the data transmission unit <NUM> may transmit transmission data including data that indicates a length of the measurement intervals. In this case, the battery management device <NUM> causes the measurement unit <NUM> to measure the characteristics of the battery cell <NUM> at cycles corresponding to the measurement intervals. Further, the data analysis unit <NUM> may generate control data for controlling charging and discharging of the battery cell <NUM> according to the analysis result on the measurement data, and transmit the control data at timings corresponding to the time intervals.

The data analysis unit <NUM> may adjust the time intervals I based on the deterioration rate of the battery cell <NUM>. The data analysis unit <NUM> may shorten the time intervals I when a difference between the calculated deterioration rate and a predetermined designed value becomes large. The data analysis unit <NUM> may shorten the time intervals I when the tendency of the deterioration of the charging capacities among the battery cells <NUM> changes. The change of the tendency of the deterioration is, for example, a case where the deterioration of the battery cells <NUM> different from the past becomes large.

As the battery cell <NUM> deteriorates, the variations in the remaining capacities of the battery cells <NUM> are likely to become large. The data analysis unit <NUM> may shorten the time intervals I as the deterioration rate of the battery cell <NUM> increases. The data analysis unit <NUM> may use an average value of the deterioration rates of the battery cells <NUM> included in the battery module <NUM>, or use a worst value. Accordingly, an increase of the adjustment amount in one cell balance processing can be suppressed.

<FIG> shows an example of a deterioration detection of the battery cell <NUM>. In the present example, the deterioration will be described using a temporal change of the full charge capacity of the battery cell <NUM>, but the deterioration may also be detected from a temporal change of characteristics other than the full charge capacity. The data analysis unit <NUM> of the present example detects a deviation amount D between a measurement value of the full charge capacity of the battery cell <NUM> and a reference value of the full charge capacity, as a deterioration amount of the battery cell <NUM>. In <FIG>, the measurement values of the full charge capacity are plotted by circles. Further, a curve obtained by approximating the respective plots is indicated by a solid line.

The reference value of the full charge capacity can be acquired from the reference characteristics of the full charge capacity. The reference characteristics of the full charge capacity are characteristics that show a change of the full charge capacity with respect to the number of charging/discharging times of the battery cell <NUM>. The reference characteristics of the full charge capacity may be a designed value set by the manufacturer of the battery cell <NUM>, or may be a statistical value acquired statistically. The reference characteristics of the battery cell <NUM> may be recorded in advance in the data analysis unit <NUM>. Note that the data analysis unit <NUM> may correct the reference characteristics based on a temperature of the battery cell <NUM>, a time during which the battery cell <NUM> is left in a full charge state or a minimally-charged state, or the like. The data analysis unit <NUM> may calculate a deviation rate at which the battery cell <NUM> deviates from the reference characteristics, from the relationship between the number of charging/discharging times and the deviation amount D.

The data analysis unit <NUM> may adjust the time intervals I described with reference to <FIG> based on the deviation amount D or the deviation rate. The data analysis unit <NUM> may shorten the time intervals I when the deviation amount D or the deviation rate becomes equal to or larger than a predetermined reference value. In the example of <FIG>, the time interval I1 is adjusted to I2 at a timing the deviation amount D becomes equal to or larger than the reference value. Furthermore, when the deviation amount D becomes equal to or larger than the reference value, the data analysis unit <NUM> may notify the battery management device <NUM> to that effect.

Furthermore, the data analysis unit <NUM> may shorten the time intervals I when a deviation tendency between the characteristics of the battery cell <NUM> and the reference characteristics changes. For example, the data analysis unit <NUM> may judge that the deviation tendency has changed when a difference of the measurement value obtained this time from an approximate curve obtained by approximating the measurement values obtained up to last time, becomes equal to or larger than a predetermined value. In the example of <FIG>, the time interval I2 is adjusted to I3 at a timing the deviation tendency changes. Furthermore, when the deviation amount D becomes equal to or larger than the reference value, the data analysis unit <NUM> may notify the battery management device <NUM> to that effect.

<FIG> shows another example of the analysis content by the data analysis unit <NUM>. The data analysis unit <NUM> of the present example generates failure data indicating that a failure has occurred in the battery cell <NUM>, based on the analysis result on the analysis data. As shown in <FIG>, the data transmission unit <NUM> may transmit transmission data including the failure data to the battery management device <NUM>.

The data analysis unit <NUM> of the present example generates the failure data based on a temporal change of the full charge capacity Qmax of the battery cell <NUM>. When a decrease amount ΔQ of the full charge capacity calculated from the analysis data obtained this time from the full charge capacity calculated from the analysis data obtained last time exceeds a predetermined reference value, the data analysis unit <NUM> may judge that a failure has occurred in the battery cell <NUM>. Accordingly, peeling of electrodes or a rapid characteristics change can be detected to be notified to the battery management device <NUM>. Note that the characteristics to be used for judging a failure are not limited to the full charge capacity.

<FIG> shows another example of the analysis content by the data analysis unit <NUM>. The data analysis unit <NUM> of the present example detects a replacement of the battery cell <NUM> based on the analysis result on the analysis data.

The data analysis unit <NUM> of the present example detects whether the battery cell <NUM> has been replaced based on a temporal change of the full charge capacity Qmax of the battery cell <NUM>. When an increase amount +Q of the full charge capacity calculated from the analysis data obtained this time from the full charge capacity calculated from the analysis data obtained last time exceeds a predetermined reference value, the data analysis unit <NUM> may judge that the battery cell <NUM> has been replaced. The data analysis unit <NUM> may also judge that the battery cell <NUM> has been replaced based on a magnitude of the change of the characteristics other than the full charge capacity, such as the derivation characteristics.

<FIG> shows an operation example of the data analysis unit <NUM>. <FIG> shows time series analysis data <NUM> and <NUM> recorded by the analysis data recording unit <NUM>. Timings of measuring the characteristics of the battery cell <NUM> differ between the analysis data <NUM> and <NUM>.

The measurement unit <NUM> of the present example allocates cell identification data Ce to the measurement data of each of the battery cells <NUM> based on the position of each of the battery cells <NUM> in the battery module <NUM>. For example, the measurement unit <NUM> allocates the cell identification data Ce for each voltmeter <NUM> shown in <FIG>. Therefore, even when any of the battery cells <NUM> in the battery module <NUM> is replaced, the same cell identification data Ce is allocated to the battery cell <NUM> that is to be replaced and the battery cell <NUM> used for the replacement. In this case, if measurement data is managed for each cell identification data Ce in the analysis device <NUM>, the measurement data of the battery cell <NUM> that is to be replaced and the measurement data of the battery cell <NUM> used for the replacement will be mixed up while being managed. In this case, it may become impossible to accurately analyze the characteristics of the battery cell <NUM>.

The data analysis unit <NUM> allocates new cell identification data Ce to the battery cell <NUM> corresponding to the same cell identification data Ce, based on a history of measurement data corresponding to the same cell identification data Ce. As described with reference to <FIG>, when a change of the full charge capacity calculated from the history of the measurement data is equal to or larger than a reference value, the data analysis unit <NUM> judges that the battery cell <NUM> has been replaced, and updates the cell identification data Ce of the battery cell <NUM>. In the example of <FIG>, cell identification data Ce12 is updated to cell identification data Ce12b. Accordingly, it becomes possible to prevent mix-up of the measurement data of the battery cell <NUM> before and after the replacement.

<FIG> shows another configuration example of the battery module <NUM>. The battery module <NUM> of the present example includes a BMS <NUM> (Battery Management System) that manages the battery module <NUM>. The BMS <NUM> may be the battery management device <NUM> shown in <FIG>, or may be a circuit communicable with the battery management device <NUM>. The BMS <NUM> notifies the remaining capacity gauge <NUM> of the estimated remaining capacity of the battery cell <NUM>. The BMS <NUM> may notify the estimated remaining capacity of an individual battery cell <NUM>, or may notify a sum of the estimated remaining capacities of the plurality of battery cells <NUM>.

The remaining capacity gauge <NUM> may be mounted in the battery module <NUM>, or may be arranged outside the battery module <NUM>. The remaining capacity gauge <NUM> displays information related to the notified estimated remaining capacity.

The data analysis unit <NUM> may compare the estimated remaining capacity of the battery cell <NUM> notified by the BMS <NUM> and the analyzed remaining capacity of the battery cell <NUM> analyzed from the measurement data. The data transmission unit <NUM> may transmit transmission data including the compared result. Accordingly, it becomes possible to notify the battery management device <NUM> of whether the estimated remaining capacity displayed by the remaining capacity gauge <NUM> is correct. The compared result may be a difference between the estimated remaining capacity and the analyzed remaining capacity.

Various embodiments of the present invention may be described with reference to flowcharts and block diagrams, whose blocks may represent (<NUM>) steps of processes in which operations are executed or (<NUM>) sections of apparatuses responsible for executing operations. Certain steps and sections may be implemented by a dedicated circuit, a programmable circuit supplied together with computer-readable instructions stored on computer-readable media, or processors supplied together with computer-readable instructions stored on computer-readable media. The dedicated circuit may include a digital and/or analog hardware circuit, or may include an integrated circuit (IC) and/or a discrete circuit. The programmable circuit may include a reconfigurable hardware circuit including logical AND, logical OR, logical XOR, logical NAND, logical NOR, and other logical operations, a memory element such as a flip-flop, a register, a field programmable gate array (FPGA) and a programmable logic array (PLA), and the like.

A computer-readable medium may include any tangible device that can store instructions to be executed by a suitable device, and as a result, the computer-readable medium having instructions stored thereon includes an article of manufacture including instructions which can be executed to create means for performing operations specified in the flowcharts or block diagrams. Examples of the computer-readable medium may include an electronic storage medium, a magnetic storage medium, an optical storage medium, an electromagnetic storage medium, a semiconductor storage medium, and the like. More specific examples of the computer-readable medium may include a floppy (registered trademark) disk, a diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an electrically erasable programmable read-only memory (EEPROM), a static random access memory (SRAM), a compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a Blu-ray (registered trademark) disk, a memory stick, an integrated circuit card, and the like.

Computer-readable instructions may include assembler instructions, instruction-set-architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state-setting data, or either source code or object code written in any combination of one or more programming languages, including an object oriented programming language such as Smalltalk, JAVA (registered trademark), C++, etc., and conventional procedural programming languages, such as the "C" programming language or similar programming languages.

Computer-readable instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatuses, or to a programmable circuit, locally or via a local area network (LAN), wide area network (WAN) such as the Internet, or the like, to execute the computer-readable instructions to create means for performing operations specified in the flowcharts or block diagrams. Examples of the processor include a computer processor, a processing unit, a microprocessor, a digital signal processor, a controller, a microcontroller, and the like.

<FIG> illustrates an example of a computer <NUM> in which a plurality of aspects of the present invention may be embodied in whole or in part. A program that is installed in the computer <NUM> can cause the computer <NUM> to function as or perform operations associated with apparatuses of the embodiments of the present invention or one or more sections thereof, and/or cause the computer <NUM> to perform processes of the embodiments of the present invention or steps thereof. Such programs may be executed by a CPU <NUM> to cause the computer <NUM> to perform certain operations associated with some or all of the blocks in the flowcharts and block diagrams described in the present specification.

The computer <NUM> according to the present embodiment includes the CPU <NUM>, a RAM <NUM>, a graphics controller <NUM>, and a display device <NUM>, which are mutually connected by a host controller <NUM>. The computer <NUM> also includes input/output units such as a communication interface <NUM>, a hard disk drive <NUM>, a DVD-ROM drive <NUM>, and an IC card drive, which are connected to the host controller <NUM> via an input/output controller <NUM>. The computer also includes legacy input/output units such as a ROM <NUM> and a keyboard <NUM>, which are connected to the input/output controller <NUM> via an input/output chip <NUM>.

The CPU <NUM> operates according to programs stored in the ROM <NUM> and the RAM <NUM>, thereby controlling each unit. The graphics controller <NUM> obtains image data generated by the CPU <NUM> on a frame buffer or the like provided in the RAM <NUM> or in itself, and causes the image data to be displayed on the display device <NUM>.

The communication interface <NUM> communicates with other electronic devices via a network. The hard disk drive <NUM> stores programs and data used by the CPU <NUM> in the computer <NUM>. The DVD-ROM drive <NUM> reads the programs or the data from the DVD-ROM <NUM>, and provides the hard disk drive <NUM> with the programs or the data via the RAM <NUM>. The IC card drive reads programs and data from the IC card, or writes programs and data to the IC card.

The ROM <NUM> stores therein a boot program or the like executed by the computer <NUM> at the time of activation, or a program depending on the hardware of the computer <NUM>. The input/output chip <NUM> may also connect various input/output units to the input/output controller <NUM> via a parallel port, a serial port, a keyboard port, a mouse port, or the like.

The program is provided by a computer-readable medium such as the DVD-ROM <NUM> or the IC card. The program is read from a computer-readable medium, installed in the hard disk drive <NUM>, the RAM <NUM>, or the ROM <NUM> which are also examples of the computer-readable medium, and executed by the CPU <NUM>. The information processing described in these programs is read by the computer <NUM> and provides cooperation between the programs and various types of hardware resources. The apparatus or method may be configured by implementing operations or processing of information according to use of the computer <NUM>.

For example, in a case where communication is performed between the computer <NUM> and an external device, the CPU <NUM> may execute a communication program loaded in the RAM <NUM> and instruct the communication interface <NUM> to perform communication processing on the basis of processing described in the communication program. Under the control of the CPU <NUM>, the communication interface <NUM> reads transmission data stored in a transmission buffer processing area provided in a recording medium such as the RAM <NUM>, the hard disk drive <NUM>, the DVD-ROM <NUM>, or the IC card, transmits the read transmission data to the network, or writes reception data received from the network in a reception buffer processing area or the like provided on the recording medium.

In addition, the CPU <NUM> may cause the RAM <NUM> to read all or a necessary part of a file or database stored in an external recording medium such as the hard disk drive <NUM>, the DVD-ROM drive <NUM> (DVD-ROM <NUM>), the IC card, or the like, and may execute various types of processing on data on the RAM <NUM>. Next, the CPU <NUM> writes back the processed data to the external recording medium.

Various types of information such as various types of programs, data, tables, and databases may be stored in a recording medium and subjected to information processing. The CPU <NUM> may execute, on the data read from the RAM <NUM>, various types of processing including various types of operations, information processing, conditional judgement, conditional branching, unconditional branching, information retrieval/replacement, or the like described throughout the present disclosure and specified by instruction sequences of the programs, and writes the results back to the RAM <NUM>. In addition, the CPU <NUM> may search for information in a file, a database, etc., in the recording medium. For example, when a plurality of entries, each having an attribute value of a first attribute associated with an attribute value of a second attribute, are stored in the recording medium, the CPU <NUM> may search for an entry matching the condition whose attribute value of the first attribute is designated, from among the plurality of entries, and read the attribute value of the second attribute stored in the entry, thereby obtaining the attribute value of the second attribute associated with the first attribute satisfying the predetermined condition.

The programs or software modules described above may be stored in a computer-readable medium on or near the computer <NUM>. In addition, a recording medium such as a hard disk or a RAM provided in a server system connected to a dedicated communication network or the Internet can be used as a computer-readable medium, thereby providing a program to the computer <NUM> via the network.

Claim 1:
An analysis device (<NUM>), comprising:
a data acquisition unit (<NUM>) configured to acquire, via a network (<NUM>), analysis data including measurement data (Me) obtained by measuring characteristics related to charging and discharging of one or more battery cells (<NUM>) included in one or more battery modules (<NUM>) and identification data (Mo, Ce) for identifying at least one of the battery modules (<NUM>) or the battery cells (<NUM>);
a data analysis unit (<NUM>) configured to analyze characteristics related to a charging capacity of at least one of the battery cells (<NUM>), based on the analysis data acquired by the data acquisition unit (<NUM>); and
a data transmission unit (<NUM>) configured to transmit transmission data corresponding to an analysis result obtained by the data analysis unit (<NUM>) via the network (<NUM>),
characterized in that
the battery cell (<NUM>) is identified by cell identification data (Ce),
the data analysis unit (<NUM>) is configured to allocate, based on a history of the measurement data (Me) corresponding to one piece of the cell identification data (Ce), a new piece of the cell identification data (Ce) to the battery cell (<NUM>) corresponding to the one piece of the cell identification data (Ce), and thus update the cell identification data (Ce) of the battery cell (<NUM>), and
the data analysis unit (<NUM>) is configured to judge that the battery cell (<NUM>) has been replaced, and update the cell identification data (Ce) of the battery cell (<NUM>) from the one piece of the cell identification data (Ce) to the new piece of the cell identification data (Ce), when a change of a full charge capacity calculated from the history of the measurement data (Me) is equal to or larger than a reference value.