GB2461350A

GB2461350A - Battery deterioration determination based on internal resistances per temperature range

Info

Publication number: GB2461350A
Application number: GB0823450A
Authority: GB
Inventors: Hiroshi Arita; Takeyuki Itabashi; Youhei Kawahara; Motomi Shimada
Original assignee: Hitachi Ltd
Current assignee: Hitachi Ltd
Priority date: 2007-12-27
Filing date: 2008-12-23
Publication date: 2010-01-06
Anticipated expiration: 2028-12-23
Also published as: GB0823450D0; GB2461350B

Abstract

A stable deterioration rate for a secondary battery can be obtained by managing the internal resistances obtained through measurement data per temperature, increasing the sample data per temperature, averaging the internal resistances and comparing the internal resistance averaged for the overall temperature with a reference internal resistance.

Description

BATTERY CONTROL METHOD AND SYSTEM

BACKGROUND OF THE INVENTION

Field of the invention

The present invention relates to a battery control method and its system for determining the deterioration of secondary batteries.

Description of the related art

There are known arts related to determining the deterioration state of secondary batteries such as lead, nickel hydride and lithium batteries used in wheeled devices such as automobiles and railways or in UPS for backup.

Generally, the internal resistance of secondary batteries is related to the deterioration rate of the secondary batteries, and the deterioration rate can be determined by the rate of increase of the internal resistance with respect to the reference internal resistance. Therefore, the deterioration rate of the secondary batteries can be obtained by measuring the internal resistance thereof.

Further, Japanese patent application laid-open publication No. 2005-091217 (patentdocumentl) discloses anartof obtaining the accurate internal resistance and determining the deterioration state of a secondary battery by performing temperature correction, since the internal resistance of the secondary battery varies greatly depending on the state of charge and especially the temperature of the secondary battery.

However, according to the method disclosed in patent document 1, a sampling of 20 kHz or greater is required, so it requires high-speed and high-accuracy sensors and a high processing ability of microcomputers. Furthermore, when the internal resistance is measured during operation, since the battery state is varied during measurement of the internal resistance, the accuracy of the measured value of internal resistance and the accuracy of deterioration rate cannot be improved.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a battery control method and its system for determining the deterioration of a battery and to realize accurate measurement of the battery state.

In order to solve the problems of the prior art, the present invention provides a battery control system comprising at least one battery, and a control circuit; characterized in comprising a sensor for detecting a battery state information of the battery; an internal resistance computation means for computing an internal resistance based on the battery state information from the sensor; an internal resistance retention means for retaining the internal resistance per temperature range of the battery; and a deterioration determinationmeans for comparing a reference internal resistance per temperature range of the battery and a computed internal resistance, fordeterminirigadeterioration rate of the battery.

Furthermore, in order to solve the problems of the prior art, the present invention provides a battery control method for controlling the battery comprising at least one battery, characterized in detecting a battery state information of the Jattery via a sensor; computing an internal resistance based on the battery state information; retaining the internal resistance per temperature range of the battery; and comparing a reference internal resistance per temperature range of the battery and a computed internal resistance to determine a deterioration rate.

In order to solve the problems of the prior art, the present invention utilizes various resistance information in the internal resistance retention means, and determines that a battery is malfunctioning when an estimated deterioration rate within a certain temperature range differs greatly compared to other temperature ranges, which is notified to the user, and also confirms the internal resistance during periodic maintenance so as to detect signs of error in advance.

According to the present invention, even if the number of samples is too small and the estimation error may be great within a certain period of time, since internal resistance tables are stored per temperature range, so that the number of samples can be increased and the estimation error of internal resistances can be minimized.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. I is a block diagram of a battery control system 1000 according to the present invention; FIG. 2 is a view showing the configuration of a reference internal resistance table according to the present invention; FIG. 3 is a circuit diagram showing the equivalent circuit of assembled batteries according to the present invention; FIG. 4 is a view showing the configuration of a reference internal resistance retention means according to the present invention; FIG. 5 is a view showing the configuration of a reference internal resistance retention means according to the present invention; FIG. 6 is a view showing the configuration of a measured internal resistance retention means for retaining the internal resistances per temperature and state of charge according to the present invention; FIG. 7 is a view showing the configuration of a measured internal resistance retention means for retaining the accumulated resistance and number of resistances per temperature according to the present invention; FIG. S is a view showing the configuration of a measured internal resistance retention means having a function to record the update time per temperature according to the present invention; FIG. 9 is a block diagram showing the configuration of a battery system and a battery control unit according to the present invention; FIG. 10 is another block diagram showing the configuration of a battery system and a battery control unit according to the present invention; FIG. 11 is another block diagram showing the configuration of the battery control unit according to the present invention; FIG. 12 is a block diagram in which the present invention is applied to a hybrid railway vehicle; FIG. 13 is a block diagram of assembled batteries in which the present invention is applied to a hybrid railway vehicle; FIG. 14 is a configuration diagram of a battery system in which a plurality of assembled batteries are connected in parallel according to the present invention; FIG. 15 is a block diagram showing another embodiment of the battery control system according to the present invention; FIG. 16 is a view showing one configuration example of a difference table according to the present invention; FIG. 17 is a view showing the algorithm for collecting the estimated error of deterioration rate according to the present invention; FIG. 18 is a view showing another algorithm for collecting the estimated error of deterioration rate according to the present invention; FIG. 19 is a block diagram showing another embodiment of the battery control system according to the present invention; FIG. 20 is a block diagram showing another embodiment of the battery control system according to the present invention; and FIG. 21 is a block diagram showing another embodiment of the battery control system according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Now, the preferred embodiments of the system for estimating the deterioration of secondarybatteries according to the present invention will be described with reference to the drawings.

[Embodiment 1) FIG. 1 isaconfigurationdiagramofabatterycontrol system 1000.

The battery control system 1000 is composed of a battery system 1 and a battery control device 2, wherein the battery system 1 includes an assembled battery 10 an a sensor 100. The assembled battery 10 is formed by connecting a plurality of electric cells 11 in series. Further, the sensor 100 includes a current sensor 101 for measuring the current flow of the assembled battery 10, a voltage sensor 102 for measuring the total voltage of the assembled battery 10, and a temperature sensor 103 for measuring the temperature of the assembled battery 10. Thetemperaturesensorl03isplacedontheassembledbattery so as to either measure or estimate the highest temperature of the electric cells 11.

The battery control device 2 is composed of an analog to digital converter 21 and a battery state estimation device 20, wherein the analog to digital converter 21 performs sampling of the sensor information which are analog data output from the sensor 100 at i cycles to convert the same into digital data, which are output to the battery state estimation device 20.

Hereafter, the digital sampling data of the current data from the current sensor 101 is referred to as {ik}, the sampling data of the voltage data from the voltage sensor 102 is referred to as {CCVk}, and the sampling data of the temperature data from the temperature sensor 103 is referred to as {T}.

The battery state estimation device 20 is composed of a deteriorationestimationdevice20l, astateofchargeestimation means 202 and a reference internal resistance table 210. The state of charge estimation device 202 estimates the state of charge (SOC) and the permissible charge and discharge current of the assembled battery 10 based on the information from the sensor 100 via the analog to digital converter 21.

The deterioration estimation device 201 is composed of an internal resistance computationmeans 2000, ameasured internal resistanceretentionmeans2lOO, areferenceinternal resistance retention means 2110, a deterioration estimation computation means 2200, a measured internal resistance storage means 2120 and a reference internal resistance storage means 2130. The internal resistance computation means 2000 and the deterioration estimation computation means 2200 perform computation periodically at a computation cycle i.

The deterioration rate of a secondary battery can be computed based on the rate of increase of the internal resistance from the reference internal resistance.

FIG. 2 shows the variation of internal resistance used as referencewithrespecttotemperatureandstateofcharge. Since the internal resistance used as reference has a nonlinear property as illustrated, it is generally stored as an internal resistance table with respect to temperature and state of charge.

Further, due to limitations of memory size, the interval between the temperature and state of charge cannot be set in a tine manner, and the reference internal resistancernustbeobtainedvia linear interpolation of the data having a rough grid point, so the referenceinternairesistancealsohaserrors. Especiallywhen the battery state of the secondary battery varies greatly, the above-described errors of the reference internal resistance become greater. In addition, by the influence of sensor error of the sensor 100, the deterioration rate estimated from a few internal resistances may fluctuate greatly as much as tens of % each time the computation is performed. Actually, however, within the normal range of use, the increase of deterioration rate is approximately 1% permonth, so an accurate deterioration rate cannot be obtained from the above-described computation.

Therefore, according to the present invention, the measurement points of the internal resistance is increased, and the average thereof is compared with the overall reference

B

internal resistance retention means to determine the level of increase of the internal resistance, making it possible to minimize the influence of error and to suppress the fluctuation of deterioration rate to a few percents.

The processes in the deterioration estimation device 201 will now be described.

In the internal resistance computation means 2000, the internal resistance {Rk} is obtained from the sampling data by sensor 100, which is registered in the measured internal resistance retention means 2100, and the reference internal resistance is taken out from the reference internal resistance table 210 based on the state of charge of the state of charge computation means 202, which is registered in the reference internal resistance retention means 2110.

Expression 1 shows an expression for calculating the internal resistance Rk. Since the current difference (Ik-Ik1) is the denominator, computation error will increase if the current difference is small, so the internal resistance is computed when the current difference is lo or greater.

[Expression 1] ccv -ccv R = k k-l however, I -I > I k _ k k-i 0 k k-i Expression 1 can be derived as follows. At first, the assembled battery 10 is composed of electric cells 11 connected in series, and can be expressed by the equivalent circuit shown in FIG. 3. In FIG. 3, 1101 represents electromotive force (open circuit voltage; OCV), 1102 represents internal resistance (R), 1103 represents impedance (Z) arid 1104 represents capacitance component (C) . It is expressed by the parallel connection pair of impedance 1103 and capacitance component 1104 and the serial connectionof inrierresistance 1102 andelectromotive force 1101.

Further, expression 2 shows an expression for computing inter-terminal voltage (CCV) of the assembled battery 10 when current i is applied to the assembled battery 10.

[Expression 21 CCV=OCV+RI+V In the expression, Vp is the electrochemical polarization voltage, which corresponds to the voltage of the parallel connection pair of Z and C. Further, in the state of charge estimation means 202, open circuit voltage (OCV) is used to compute the state of charge (SOC) and the permissible charge and discharge current, but when the assembled battery 10 is charged and discharged, it is impossible to directly measure the open circuit voltage. Therefore, as shown in expression 3, theopencircuitvoltage is calculatedbysubtracting IRdrop and Vp from CCV. Further, the art disclosed in Japanese patent applicationlaid-openpublicationNo. 2003-3o3627canbeapplied to computing the state of charge and the permissible charge and discharge current in the state of charge estimation means.

[Expression 3] OCV=CCV-RI-V Expression 4 shows an expression for computing the internal resistance R from the difference with the immediately preceding sampling value. It can be calculated from expression 2 that: [Expression 411 CCVk _CCVk_l (OCV+RIk +Vp)_(OCV'+RIk 1 +V,) =R(Ik-Ikl)+(OCV-OCV')-F(Vp-V,) therefore, -ocv-ocvl+v -v

_____________________-______________

1kk-1 kk-l Measurable data Unmeasble data Now, the second term of expression 4 representing the unmeasurable data is dependent on the current k of the battery, but it is a capacitor component, so that by suppressing the computation cycle and computation current value so that it falls within a few percents of the first term, it can be considered to fall within the range of sensor error. As described, the internal resistance can be expressed by expression 1.

Next, FIG. 4 shows the measured internal resistance retention means 2100, and FIG. 5 shows the reference internal resistance retention means 2110. The measured internal resistance retentionmeans 2100 includes apluralityof retention means 2101 for storing a plurality of measured internal resistance values. The number of retention means 2101 corresponds to the reference internal resistance table, and in this example, it is described as temperature ranges of 10 °C units.

Further, the reference internal resistance retention means 2110 similarly includes a plurality of retention means 2111 for storing measured internal resistance values, and the number of retention means 2111 should preferably be the same as that of the measured internal resistance retention means 2100.

The value of the internal resistance fluctuates greatly depending on the state of charge and especially the temperature of the battery. Therefore, in order to minimize the effect of error, a range of the state of charge where the fluctuation of internal resistance due to varied state of charge is minimum is determined per temperature range, and only when the state of charge of the battery is within that range, the obtained internal resistance R is retained in the measured internal resistance retention means 2100. Further, the internal resistance corresponding to the state of charge becomes greater as temperature becomes lower, and the range of the state of charge retained in the measured internal resistance retention means 2100 becomes narrower. Therefore, when the temperature of the battery falls below the temperature where the range of the state of charge retained by the measured internal resistance retention means 2100 is narrow (for example, below 20 %) , the values will not be retained in the measured internal resistance retention means 2100.

The above range can be determined based on the property of the battery, so the range of temperature and the range of state of charge to be retained in the internal resistance retentionrneans2l00canbedeterminedinadvance. Inthepresent embodiment, the range is set to be 0 °C or greater.

As for the range of use of the state of charge, when the internal resistance fluctuates, as shown inFIG. 6, byseparately retaining the state of charge as parameter similar to temperature, the number of measured internal resistances retained in the measured internal resistance retention means 2100 can be increased. The registration process of the measured internal resistance retention means 2100 is as follows. The internal resistance Rk computed by the internal resistance computation means 2000 is retained in a retention means 2101 of the corresponding temperature range of the measured internal resistance retention means 2100, based on the temperature data obtained from the temperature sensor 103. For example, if the temperature data from the temperature sensor 103 is 23 °C, the internal resistance is retained in retention means 210l-3 corresponding to the 20 °C range. Similarly, the reference internal resistance of the same condition (same state of charge and same temperature) is read out from the reference internal resistance table 210, and the reference resistance is registered in the reference internal resistance retention means 2110.

Similarly, this registration is retained in the retention means 2111 of the corresponding temperature range in the reference internal resistance retention means 2110. Further, as shown in the configuration of the internal resistance retention means of FIG. 7, the configuration of the retention means 2101 per temperature range includes an accumulated resistance 2102 and quantity 2103. This is realized by adding the resistance to the accumulated resistance 2102 and adding 1 to the quantity 2103 upon registering a resistance.

Expression 5 shows an expression for computing the average value per temperature range of the computation in an estimated deterioration computation means 2200.

[Expression 5] Average resistance per temperature range = accumulated resistance (2102) � quantity (2103) Further, iftheaccumulatedresistance2lO2istoberetajned to fixed point, the accumulated resistance 2102 may overflow, due to the limitation of bit numbers (for example, in the case of unsigned 16-bit data, the range is 0 to 65535) . Therefore, the maximum value of the accumulated resistance 2102 and the value of the quantity 2103 to be reduced when the resistance exceeds the maximum value is determined in advance, and when the accumulated resistance 2102 exceeds the maximum value, the quantity 2103 is reduced to the set number to be reduced.

Expression 6 shows the expression of such change. As described, overflow can be prevented by changing the accumulated resistance 2102 so that the average value becomes the same.

[Expression 6] New accumulated restance (2102) = new quantity after reduction current accumulated resistance >< current quantity The estimated deterioration computation means 2200 will now be described. The estimated deterioration computation means 2200 reads in the internal resistance data from themeasured internal resistance retentionmeans 2100, and after calculating the average per temperature or the like, the average of the temperatures is obtained to acquire a central tendency of the measured internal resistance, the details of which will follow.

As for the reference internal resistance retention means 2110, similarly, the average per temperature or the like is computed, and the average of the temperatures is obtained to acquire a central tendency of the reference internal resistance, the details of which will follow.

A central tendency of the measured internal resistance is computed from the plurality of measured internal resistances retained in the measured internal resistance retention means 2100. At first, a central tendency per each temperature range is obtained by computing the average or performing a least squares method of the plurality of resistances retained per temperature range (2101) inthemeasuredinternairesistanceretentionmeans 2100. Thereafter, the average of the obtained central tendency resistances of the temperature ranges is computed to obtain one central tendency of the measured internal resistance. As for the reference internal resistance retention means 2110, similarly, a central tendency per temperature range (2111) is obtained by computing the average or performing a least squares method, and thereafter, the average of the obtained central tendency resistances of the temperature ranges is computed to obtain one central tendency of the reference internal resistance.

As shown in expression 7, the deterioration rate (SOH: State of Health) is obtained from the ratio of two central tendencies.

As described, by obtaining the deterioration rate from the ratio of the central tendencies of the average values of multiple internal resistances, the effect of sensor error, computational error and error of the reference internal resistance table can be minimized and the accuracy can be improved, compared to the case of obtaining the average of deterioration rate per measurement point.

[Expression 7] measured internal resistance central tendency Deterioration rate -reference internal resistance central tendency Expression B shows an expression for obtaining the central tendency. In the expression, the number of data in temperature range a is referred to as na, and the i-th data of temperature range a is referred to as ra,j.

[Expression 8] Central tendency =------r Na a1 Further, expression 9 shows an expression for obtaining the central tendency when performing weight averaging using the number of data n3 per temperature range.

[Expression 9] Central tendency = 1 r i a. a, a Further, the operating temperature limit of the assembled battery 10 varies between summer and winter. For example, in case the battery temperature reaches the 60 °C range only during summer, if the average of all temperatures is used, the measured internal resistance of the 60 °C range during summer is used as it is in winter. Therefore, as shown in FIG. 8, the measured internal resistance retention means 2100 and the reference internal resistance retention means 2110 are provided with a function to store the update time 2105 per temperature range, so that when the internal resistance computation means 2000 writes in the internal resistance as internal resistance data 2104 to the measured internal resistance retention means 2100 and the reference internal resistance retention means 2110, the value of the update time is changed. The internal resistance computation means 2000 checks the value of the update time 2105, andwhentheupdate time is old, aprocess tominimize the effect of the previous resistance data is performed by writing the internal resistance of the measured internal resistance retention means 2100 and the reference internal resistance retention means 2110 after clearing the value of the internal resistance data 2104 or by compressing the same.

Further, by retaining the update time in the measured internal resistance retention means 2100 and the reference internal resistance retention means 2110, the estimated deterioration computation means 2200 can change the weight of a certain temperature range according to the update time when computing the central tendencyof the internal resistance. Thus, whencomputingtheinternalresistancecentraltendencyinwinter, for example, the weight of the 60 °Crange resistance dataupdated in summer can be reduced during computation. Vhen the battery is deteriorated, the internal resistance increases and the temperature rise becomes rapid, by which the battery temperature may reach the 60 00 range even during winter, so the computation of the internal resistance central tendency can be performed corresponding to deterioration considering the update time.

Expression 10 shows an expression taking into consideration the above phenomenon, by generalizing the computation of each temperature range and the computation of the central tendency, and performing the computation using functions.

[Expression 10] Central tendency = fg1r11,r12, rin) ,g( N,1, N,2," FrN,nN)) As described above, when the internal resistance has high dependency with respect to temperature, the error of sensor and temperature can be minimized by collecting the internal resistances per temperature, performing computation per temperature, and then performing computation for the overall temperature.

FIG. 9 illustratesamethodforrealizingthebatterysystem 1. The battery system 1 is composed of an assembled battery and a sensor 100, and the battery control system 2 is composed of an analog to digital converter 21, a computation means 22, a storage means 23 andanonvolatile storage means 24. Further, as shown in FIG. 10, the analog to digital converter 21 can be disposed in the battery system 1.

The configuration of the battery control system 2 according to FIG. 9 is illustrated in FIG. 11.

The computation means 22 includes an internal resistance computation means 2000, an estimated deterioration computation means 2200 and a start-end processing means 2300, which is realized by executing the program 2140 describing the contents of the process and the work area 2150.

Since the internal resistance retention means 2100 and 2110 are placed on the storage means 23 which is a volatile memory, the internal resistance data will disappear when power is turned off. In order to prevent this, the start-end processing means 2300 saves the internal resistance data in the internal resistance retention means 2100 and 2110 to the internal resistance storage means 2120 and 2130 within the nonvolatile storage means 24. At start time, the start-end processing means 2300 returns the data from the internal resistance storage means 2120 and 2130 to the internal resistance retention means 2100 and 2110. Thereby, it becomes possible to prevent elimination of data of the internal resistance retention means 2100 and 2110 when power is turned off.

At this time, by converting (compressing) the resistance data and saving the same in the internal resistance storage means 2120 and 2130, it becomes possible to reduce the necessary size of the nonvolatile storage means 24. The converting method can be, for example, the average and quantity per temperature.

The storage means 23 is composed of a volatile memory such as SRAN and DR1M, and includes a measured internal resistance retention means 2100, a reference internal resistance retention means2llOandworkarea2l50. Further, thenonvolatile storage means 24 is composed of a nonvolatile memory such as a flash memory or a hard disk, and includes a reference internal resistance table 210, a measured internal resistance storage means 2120, a reference internal resistance storage means 2130 and a program 2140.

In general, the access speed to a volatile memory is faster than that to a nonvolatile memory. Using this phenomenon, the processing performance of the computation means 22 can be improved by having the start-end processing means 2300 copy the reference internal resistance table 210 and the program 2140 in the nonvolatile storage means 24 to the storage means 23.

In the above-described embodiment, if the fluctuation of the internal resistance with respect to the state of charge is similarly large, it is possible to reduce the estimation error of the internal resistance due to fluctuation of state of charge by storing an internal resistance table per state of charge in the reference internal resistance retention means 2110.

In a battery, for protection of the battery, the state of charge and discharge current is restricted so that the CCV falls within a predetermined voltage range. Further, as shown in

S

expression 2, CCV tends to be higher during charge and lower during discharge compared to when the current is 0.

Expression 11 shows the expression for computing the maximum charge and discharge current on the charge side, and expression 12 shows the expression for computing the maximum charge and discharge current on the discharge side.

[Expression 11] Vmax -OCV charge_max R0xSOH [Expression 121 OCV_Vmin discharge_max R0XSOH Here, V and Vmjr, represent the maximum value and minimum valueofbatteryvoltage, andR0represents the reference internal resistance in the present battery state.

However, if the deterioration rate is determined to be smaller than the actual value, the battery state estimation device 20 determines, based on expressions 11 and 12, that the maximum charge and discharge current can be set to a high value.

Thereby, the voltage fluctuation width is increased and the CCV may exceed the predetermined voltage range.

Therefore, when the CCV exceeds the predetermined voltage range, the battery state estimation circuit 20 assumes that the estimation of deterioration rate has failed, and performs a process to improve the deterioration rate.

Thus, it becomes possible to protect the battery even when the deterioration rate cannot be estimated correctly, such as during starting of use.

As described, according to the present embodiment, even when the number of samples may be too small and the estimation error becomes great during a certain period of time, the number of samples can be increased by storing an internal resistance table per unit temperature, so that the estimation error of the internal resistance can be minimized.

Further according to the present embodiment, the internal resistance can be obtained based on the information on the battery during operation (such as voltage, current and temperature), the estimation of internal resistance and deterioration rate of the secondary battery can be realized even in a case where it is impossible to create a certain pattern according to the

prior art method.

According further to the present embodiment, regarding the deterioration rate computed by the rate of increase of internal resistance with the reference value, the influence of error of various sensors can be minimized by utilizing an average value of the total samplingwithout comparing the internal resistances per sampling point.

Furtheraccordingtothepresentembodiment, the information of various resistances in the internal resistance retentionmeans is used so that when a resistance of a certain temperature range is great compared to other temperature ranges, it is determined that malfunction of the battery control system has occurred,

S

which is notified to the user, and the internal resistance is confirmed during periodic maintenance in order to realize early detection of signs of malfunction.

[Embodiment 2] FIG. 12 illustrates a hybrid railway vehicle using the battery system 1.

A hybrid railway vehicle 3000 is composed of an engine 3100, agenerator 3110, aconverter 3120, an inverter 3130, anACmotor 3140, a drive wheel 3150, a brake 3160, a train control unit 3200, a plurality of battery control systems 1000, a control panel 3210 and a maintenance means 3300.

The engine 3100, the generator 3110 and the converter 3120 are connected, and when the engine 3100 rotates, AC power is generated in the generator 3110, which is converted to DC power and output from the converter 3120. The converter 3120, the assembled batteries 11 in the plurality of battery control systems 1000 and the inverter 3130 are connected. Further, the inverter 3130, the AC motor 3140 and the drive wheel 3150 are connected, and when the railway vehicle 3000 accelerates, the inverter 3130 receives DC power from the converter 3120 and the assembled battery 10, converts the same into AC power to rotate the AC motor 3140 and the drive wheel 3150 to accelerate the vehicle. When decelerating the vehicle, the AC motor 3140 is used as a generator, and the generated AC power is converted into DC power via the inverter 313 to charge the assembled battery 10.

The control of the engine 3100 and the inverter 3130 is performed by a train control unit 3200 receiving instructions via the control panel. The train control unit 3200 controls the inverter 3130 corresponding to the instructions from the control panel 3210, and receives state information (such as the state of charge, the permissible current, the deterioration rate and the temperature) of the respective assembled batteries 10 from the battery control unit 20 within each battery control system 1000, and controls the engine 3100 and brake 3160 so that the state of charge and discharge corresponds to the battery state of the respective assembled batteries.

The control panel 3210 includes a display panel 3220 for displaying conventional operation information such as speed, and a display panel 3230 for displaying the information from the battery control systems 1000. It also includes a master controller 3240 through which the driver controls the speed and brakes.

Further, by connecting a maintenance means 3300 to the train control unit 3200, the maintenance crew can check the various state information of the hybrid railway vehicle 3000 including the resistance data of each battery control system 1000 via the maintenance means 3300.

The train control unit 3200 acquires the deterioration estimation of each temperature range from the estimated deterioration computation means 2200 in each battery control unit 20, checks the differences between the estimated deteriorations and examines whether there are malfunctions. It checks whether there is a large difference (such as 10 to 20 percent) . The check can be performed in the estimated deterioration computation means 2200. It is examined whether there are any differences.

If the estimated deterioration rate of a certain temperature range has a great difference compared to other temperature ranges, it isdeterminedthat the assembledbattery 10 ismalfunctioning, and the information is displayed on the display panel 3230 of the control panel 3210, and at the same time, the train control unit 3200 changes the control pattern of the railway vehicle 3000.

Furthermore, if the temperature rise of a battery is faster than usual, the information is displayed on the display panel 3230, and the battery control unit 3200 changes the control pattern of the railway vehicle 3000.

According toone controlpattern, thebatterycontrol system 1000 including the assembled battery 10 is separated, and the remaining battery control systems 1000 are used to continue operationoftherailwayvehicle3000. Further, if it ispossible to perform control so that the assembled battery 10 does not reach the certain temperature range (such as when malfunction occurs in the temperature range of 60 °C), control is performed so that the temperature of the assembled battery 0 does not reach that certain temperature range. t

Further, the display panel 3230 displays the deterioration rate in addition to the state of charge, the temperature, the voltage and the current of each assembled batter 10, so that the driver can confirm the battery state of the respective batterieslO. Atthistime, suchasduring startingof operation, the measured internal resistance retention means 2100 in each battery control unit 20 may only have resistance data within a certain temperature range. In that case, it is displayed on the display panel 3230 that the reliability of deterioration rate is not high.

During maintenance, the data within each battery control system 1000 is examined via the maintenance means 3300 so as to check the deterioration state of each assembled battery 10, and if malfunction such as a large dispersion between the estimated deterioration rates of temperature ranges exist, it can be used as guide for replacing the assembled batteries 10.

As described, the result of measurement of the internal resistance can be retained per temperature at the battery control unit 20. Thisprocess is also applicable tohybridautomobiles, uninterruptible power systems (UPS) and dump trucks having secondary batteries.

FIG. 13 shows a configuration diagram of a battery system in which assembled batteries 10 are connected in parallel.

Expression 13 shows an expression for computing the charge and discharge current {Ik} flowing through each assembled battery in the battery system. The deterioration rate of each assembled battery lOis referred to as {SOHk}, the overall charge and discharge current is referred to as I, and the charge and discharge current {I:} flowing through each assembled battery can be computed by the distribution of internal resistance ratio of each assembled battery 10.

[Expression 13]

I i

SOHk X i SOHi Further, expression 14 shows an expression for computing the overall maximum charge and discharge current limit. When the maximum charge and discharge current of each assembled batteryl0isreferredtoas {Iijmitk}, expressionl4canbeobtained from expression 13.

[Expression 14] 1k 1 limit min111. tXSOHk X Further, if there is a current limitation due to temperature rise, the current limitation value of a battery system during deterioration can be obtained by computing the consumption power of the internal resistance in each assembled battery so that it equals the consumption power of a new battery.

Expression 15 shows an expression for obtaining the heating power by the internal resistance when the battery is new and the heating power {Pm} of the internal resistance when the assembled batteries 10 are deteriorated.

Expression 16 shows the relationship between the total maximum charge and discharge current Iljmjt0 when each assembled battery 10 is new and the maximum charge and discharge current Iiirnitat the time of deterioration. When the internal resistance corresponding to the battery state when the batteries are new is r0, the internal resistance of the assembled battery 10 at the time of deterioration is {roxSOHk}, and since the consumption power P° should be equal to the maximum value of consumption power of the internal resistance in the deteriorated state, expressions 15 and 16 are derived from P°=maxPk.

[Expression 151 P0r[Ilimit]P(rSOH2l X r012 i SOHJ [Expression 16]

I

limit 1 lImit fminSOHkx FIG. 14 shows aconfigurationdiagramof anewbattery system in which a Dc/Dc converter 1020, which is a power converter for raising and lowering voltage, is connected to an assembled batterylOorabatteryblockilOOhavingapluralityofassembled batteries 10 connected in parallel, a plurality of which are connected in parallel.

In the illustrated configuration, the Dc/Dc converter 1020 enables to control the current flowing through the battery block 1100 (load flowcontrol) . Thus, the charge anddischarge current of each battery block 1100 can be controlled so that the heating value corresponds to the heating value P° when the battery is new. Therefore, even if there are differences in deterioration rates between battery blocks 110, the influence thereof can be minimized.

For example, the maximum permissible current I1imt Ifl the battery system where the plurality of assembled batteries 10 are connected in parallel via Dc/Dc converters 1020 can be obtained as follows.

Expression 17 shows the expression of the overall charge and discharge current I in the present battery system when the charge and discharge current flowing through the battery block 1100-rn is m and the current of the DC/DC converter 1020 is { Im}.

Further, the efficiency and voltage raise ratio of each DC/DC converter 1020 are {flm} and {c}.

[Expression 17] m therefore, I=Im am m Expression 18 shows the expression for obtainin the current {Im} of each DC/DC converter 1020. When the deterioration rate of each assembled battery 10 is {SOHm}, the internal resistance corresponding to the battery state when the battery is new is r0, and the heating value of each battery block 1100 is {Pm}, all Pm is equal with expression 17.

[Expression 18] Pm=SOHmXr0im2 therefore I fli 1

JSOH Y

k ISOHk Expression 19 shows the expression for obtaining the consumption power P° by internal resistance when the maximum charge and discharge current Iljmjt° is of a new state, and the consumption power Pm by the internal resistance when the maximum charge and discharge current limit is of a deteriorated state.

[Expression 19] P°=r 1imit I 0 2' m 2 mm tk akSOHk From the above, the relational expression of the maximum charge and discharge current limit0 of a new state and the maximum charge and discharge current iljmjt of a deteriorated state is shown in expression 20.

[Expression 20] _k akJDHk 0 limit limit kck Forexample, thebatterysystemsof FIG. l3andl4arecompared, considering a case where the system is composed of the same ten assembled batteries connected in parallel, wherein nine has an SOH of 150% and one has an SQl-I of 100 %.

In the parallel connection battery system of FIG. 13, the current limitation rate accompanying deterioration is, based on expression 16, Iiirnjt/Iijmjt° = 70.0%.

On the other hand, in the battery system of FIG. 14 capable of performing load flowcontrol via DC/DC converters, the current limitation rate is, based on expression 20, Iijmjt/Iijmjt° 83.5%.

As described, according to the load flow control using DC/DC converters, itbecomespossibletopreventcurrentconcentration to the assembled battery having a low SOH (assembled battery having small internal resistance) . Thereby, in a battery system using DC/DC converters, it becomes possible to reduce the deterioration of output due to unbalanced deterioration.

[Embodiment 3] The present embodiment describes a method for realizing the improvement of accuracy of deterioration rate (state of health: SOH) estimated in each battery control system 1000 and the diagnosis of malfunction of sensors in a battery control system in which a plurality of battery control systems 1000 are connected.

FIG. 15 shows a configuration diagram of a series battery control system 10000 in which a plurality of battery control systems 1000-1, 1000-2 through 1000-n are connected in series.

The series battery control system includes a series battery state computation device 5000 in addition to battery control systems 1000-1, 1000-2 through 1000-n, which is connected to battery control devices 2 in the battery control systems 1000.

Further, each battery control system 1000 includes a current sensor 101, a voltage sensor 102 and a temperature sensor 103, wherein based on the sensor information from a sensor 100 via an analog to digital converter 21, a battery state estimation device 20 estimates the state of charge (state of charge) of the assembled battery 10, the permissible charge and discharge current and the deterioration rate (state of health) Moreover, the battery control device 2 has a communication circuit 22, through which the information of the estimated state of charge (SOC), the permissible charge and discharge current and the deterioration rate (state of health) are sent to a series control device 5000, and the command from the series control device 5000 is received.

On the other hand, the series control device 5000 computes the state of the series battery control system 10000 based on the information on the state of charge (SOC), the permissible charge and discharge current and the deterioration rate (state of health) fromeachofthebatterycontrolsystemsl000-1, 1000-2 through 1000-n, and creates and sends a command either individually or simultaneously to the respective battery control systems 1000.

The commands output from the series control apparatus 5000 include a SOH initialization request, a SOH increase request, a SOH decrease request, setting up of the increase/decrease quantity and so on.

The cause of error or abnormal value of the estimation of the deterioration rate includes, in addition to the malfunction of the battery itself, the failure or malfunction of the various sensors (current sensor 101, voltage sensor 102, temperature sensor 103) in the battery control system 1000. Therefore, it is necessary to minimize the influence of estimated deterioration rate caused by error and malfunction of the various sensors.

Thus, a method for improving the accuracy of the deterioration rate in a series connection system and a parallel connection system will now be described.

First, the method for improving the accuracy of deterioration rate (SOH) in a series connection system will be described.

In a battery control system 10000, the assembled battery is connected in series, so the current flowing through each oftheassembledbatteries 10 isthesame. Thus, it ispredicted that the state of deterioration of the assembled batteries 10 transits in a similar manner. Further, since the deterioration of battery progresses gradually, the deterioration will not be varied greatly in a day.

Regarding this point and comparing the time series variation of the deterioration rate of the respective assembled batteries and comparing the deterioration rates between the assembled batteries 10, it becomes possible to improve the accuracy of deterioration rate of the respective assembled batteries 10.

(1) Improvement of accuracy by comparing time series variation of assembled batteries 10 This is a process for improving the accuracyof deterioration rate of each battery control system, wherein the battery state estimation device 20 within each battery control system 1000 includes a measured internal resistance storage means 2120 and a reference resistance storage means 2130 as described in FIG. 1, and has a function to store the computed deterioration rate (SOH) at the time of previous power off.

Thus, the battery state estimation device 20 compares the computed deterioration rate with the deterioration rate stored at the time of previous power off, and when the difference is equal to or greater thanapredeterminedvalue, it will not update the deterioration rate, and will use the deterioration rate at the time of previous power off.

Further, upon comparison with the output of the voltage sensor 102, if the voltage (CCV) of the assembled battery 10 exceeds a predetermined voltage range, the battery state estimation circuit 20 determines that the estimated value of deteriorated rate is low, and raises the deterioration rate.

The raise of deterioration rate can be uniform, or can be varied according to the level of deflection of CCV from the predetermined voltage range.

Further, if the value of the deterioration rate during use or at the end differs more than a given value (for example, 10 to 20 %) from the deterioration rate during previous power off, it is determined that the sensor system (101 through 103) or the batteries are malfunctioning.

(2) Improvement of accuracy by comparing the deterioration rates between assembled batteries 10 A series control device 5000 takes the estimation error of deterioration rate into consideration when comparing the information of deterioration rate sent from each battery control system 1000, and when they exceed a predetermined value (for example, more than 20 %), it determines that estimation error has occurred by the influence of sensor error or the malfunction or failure of the sensors.

However, such estimation error may occur once by temporary malfunction, so the series battery control device 5000 sends a re-computation request of deterioration rate to the two battery control systems 1000 having output such deterioration rates.

The battery control system 1000 having received this re-computation request of deterioration rate clears themeasured internal resistance retention means 2100 and the reference internal resistanceretentionmeans2ll0withinthebatterystate estimation device 20, and performs the computation of deterioration rate again. During re-computation, for example, the average value of deterioration rate estimated via each battery control system 1000 or a fixed initial value can be set as the initial value of deterioration rate.

The deterioration rate after re-computation is compared again, and if the state of deterioration is still the same after re-computation of deterioration rate, output adjustment of the sensor (calibration) is performed, and the deterioration rate iscomputedagain. Ifthedeteriorationstateisstillthesame, then it is determined that malfunction has occurred to the battery or the sensor. Thus, it becomes possible to determine battery error or sensor malfunction without duplexing the sensors.

The number of times for re-computing and determining malfunction is not restricted to two times, and re-computing can be performed for more than three times. When malfunction is detected, a notice is sent to the train control unit 3200, where the notice is displayed on the display panel 3230 for displaying information from the battery control system 1000, and during maintenance, the deterioration information or the dispersion of deterioration rate of assembled battery 10 can be checked via the maintenance means 3300.

Next, we will describe the method for improving the accuracy of deterioration rate according to a parallel control system.

FIG. 13 shows a configuration diagram of a battery system in which assembled batteries 10 are connected in parallel. As shown in expression 13, if the deterioration rate {SOHk} of each assembled battery 10 can be estimated, the charge and discharge current {Ii:} of each assembled battery 10 can be estimated based on the total current I. Further, expression 21 shows an expression for computing with higher accuracy the estimated charge and discharge current {I'k}. The aforementioned expression 13 is an approximate expression computed assuming that the OCVj and the reference resistance R0 is equal among the plurality of assembled batteries 10. Further, Rk = SOHkXRO.

[Expression 211 ocv* I+ j R OCVk 1 R k :J By comparing the estimated value {I'k} of the charge and discharge current and the current {Ik} measured via the actual current sensor 101, it is possible to correct errors and to determine malfunction of the respective voltage sensors 102, correct the error of deterioration rate {SOHk} of the respective assembled batteries 10, and improve the accuracy of the deterioration rate {SOHk}.

First, the correction of error of a voltage sensor 102 and thedeterminationofmalfunctjonthereofwillbedescribed. The assembledbatteries 10 are connected inparallel, so the voltages {CCVk).of the assembled batteries are the same. Therefore, when the difference between outputs from voltage sensors 102 of the respectiveassembledbatteries 10 is widened, andthedifference between an output value of a certain voltage sensor 102 and the average output value of the voltage sensors 102 exceeds a predetermined range (for example, 5 %), it is determined that the voltage sensor 102 requires adjustment, and adjustment of sensor output (calibration) isperformed. Thereafter, when the voltage sensor 102 exceeds a predetermined range, it is determined that the voltage sensor 102 is malfunctioning, according to which the line of said voltage sensor is isolated or switched to a voltage sensor 102 of a stand-by system.

Next, the method for improving the SOH using the output of voltage sensors 102 and current sensors 101 will be described.

There are two possible methods.

The estirnatedvoltage {CCV'kjandtheestimatedcurrent{I'k} are computed per each line. The estimated voltage is computed based on expression 2, and the estimated current is computed based on expression 13. Next, as shown in expression 22 and expression 23, the output {Ik} of the current sensor 101 and the output {CCVk} of the voltage sensor 102 are compared, and the voltage difference {CCVk} and the current difference {AIk} are computed. Here, �CCVk is determined by the deterioration rates SOHk of the respective lines, and k is determined by the relationship (relative ratio) of the SOHk of the respective lines.

[Expression 221 ACCVk =CCVk -CCVk [Expression 231 AIk IkiIk Method 1 utilizes ACCVk and AIk to correct the estimated error of deterioration rate, in order to improve the accuracy.

Method 2 utilizes the AIk and the CCVk to correct the estimated error of deterioration rate, so as to improve the accuracy.

Method 1 will be described first. FIG. 16 shows a configuration of a difference table for registering the voltage difference {CCVk} andthe current difference {Ik} used inmethod 1. The difference table retains the voltage differences CCVk and the current differences AIk of the respective lines, and retains the determination result of whether the value is within a predetermined range (+(1) if the value exceeds the range in the positive direction, -(-1) if the value exceeds the range inthenegativedirection, andO if thevalue iswithintherange) In order to avoid the influence of sensor error, an average value within a predetermined time is used as CCVk and AIk. Moreover, based on the property that the internal resistance increases along with deterioration, the following relationship between the results of ACCVk and AIk and the deterioration rate (SOH) can be derived.

[Table 1] -(<0)

L ACCVk Estimated SOH: low Estimated SOH: high AIk Estimated SOH: high Estimated SOH: low According to method 1, in step 1, the voltage difference (ACCVk) is used to adjust the SOHk of the respective lines in the same manner, and then in step 2, the SOHk between the lines is adjusted by the current difference (AIk) FIG. 17 shows the algorithm of method 1.

In step 1, if the determination results of the voltage difference of all the lines are: a) all positive, then all SOHk are increased; b) all negative, then all SOHk are reduced.

The above operation is repeated for a few cycles and the SOHk of al the lines are adjusted in the same manner until the determination results of the voltage difference the conditions of a) and b) In step 2, with respect to the respective lines, if the determination results of the voltage difference and current difference are: +-(voltage difference result is positive and current difference result is negative), then the SOHk of that line is increased; and -+ (voltage difference result is negative and current difference result is positive), then the SOHk of that line is reduced. Thus, the SOHk between the lines is adjusted, and the procedure returns to step 1.

By repeating steps 1 and 2, the deterioration rate (SOHk) is adjusted and the accuracy is improved.

On the other hand, step 2 is a method of utilizing CCVk, which is the voltage of the assembled battery 10, when the error of the voltage difference 1\CCVk is great according to the accuracy of the voltage sensor 102 and the state of charge. The convergence isslowercomparedtomethodl, but thepresentmethod is also considered to be effective, considering the fact that the method is originally aimed at adjusting an error of a few percents.

According to method 2, in step 1, the two deterioration rates (SOT-I) having the greatest current difference (1k) are adjusted to control the SOH balance between the lines, and then in step 2, the voltage CCVk of the respective lines is observed, whereinifitexceedsthepredeterminedrange, thedeterioration rates (SOH) of all the lines are increased uniformly.

FIG. 18 shows the algorithm of method 2.

Instepi, the lineswhere the current differencehas exceeded the predetermined range is adjusted so that: the SOHk of the maximum line is reduced; and the SOHk of the minimum line is increased.

In step 2, if a line exists in which the output of the voltage sensor 102 in each battery control system exceeds the predetermined range, all SOHk are increased, and then the procedure returns to step 1.

By repeating steps 1 and 2, the deterioration rate (SOHk) is adjusted so as to improve the accuracy.

According to both methods 1 and 2, the amount of increase and decrease of SOH is fixed, for example, to 1%. When the SOH is not obtained in the battery control system, such as during startingof operation, the deterioration ratemay differ greatly from the actual battery deterioration rate, and the CCV, which is the voltage of the assembled battery, may deviate greatly from the usable range. In such case, the amount of increase or decrease of SOH is obtained according to the level of deviation so that no excessive load is applied on the assembled batteries 10.

Next, a configuration in which the assembled batteries 10 are connected in series-parallel connection will be described.

According to this configuration, the series connection being illustrated in FIG. 15, since current sensors 101 and voltage sensors 102 exist in the respective battery control systems 1000, the number of various sensors becomes excessive, and the costs of the overall battery system are increased.

Thus, FIG. 19 illustrates a configuration in which the current sensor 101 is used in common, utilizing the advantages of a series connection. In FIG. 19, current sensors 101 are provided at either ends to realize duplexing of the current sensors 101.

A method for reducing the number of voltage sensors 102 will now be described. Since the current flowing through the respective assembled batteries 10 is the same, by updating each assembledbattery 10 per each line unit, the state of transition of the deterioration rate can be equalized and the voltages of the assembledbatteries locanbemaintainedsubstantiallyequal.

Thus, as shown in FIG. 20, the total voltage of the assembled batteries 10 connected in series is measured via the voltage sensor 102, by which the voltage sensors 102 can be unified, and a value dividing the total voltage with the number of lines of assembled batteries 10 is used as the voltage of each assembled battery 10. Further, the battery control state estimation device 20 has a communication circuit 22, and is equipped with a function to perform communication with other battery state estimation devices 20, wherein the current sensor 101 and the voltage sensor 102 are connected to a single battery control state estimation device 20 where the current and voltage measured by the battery sensor 101 and the voltage sensor 102 are digitalized and then sent to other battery state estimation devices 20, according to which the number of connections of the current sensors 101 and the voltage sensors 102 can be cut down.

Further, conversely, the temperatures of the assembledbatteries measured by the temperature sensors 103 can be sent to the batterycontrol systemlo03-1, so that thebatterycontrol system 1003-1 canperformestimationof the state of chargeof the lines, the permissible charge and discharge current and the deterioration rate.

According to this arrangement, however, it is only possible tomeasurethevoltageofalltheassembledbatteriesloinserjes, and the deterioration of the performance for detecting the malfunction of the respective assembled batteries 10 is concerned.

Therefore, as shown in FIG. 21, cell voltage measurement meal-is 104 are provided to each battery control system 1000 for measuring the voltage of the respective cells constituting the assembled battery 10. Further, another communication circuit 23 is provided to the battery state estimation device 20 to enable communication with the cell battery measurement means 104, so as to monitor the voltage in detail in cell units and to provide a battery control system with improved safety.

According to the series-parallel connection system, the method (algorithm) for improving the accuracy of deterioration rate (SOH) of the aforementioned series connection system and parallel connection system are combined to realize the improvement of accuracy of deterioration rate (SOH) of the assembled batteries 10. In the system, the adjustment of accuracyof deterioration rates (SOH) of the assembledbatteries are performed for each line, and then the adjustment of deterioration rates are performed between the lines. During adjustment of the deterioration rate between lines, the corresponding deterioration rate adjustment of each line is performed for the deterioration rate of the assembled battery included in the line.

The present invention enables to estimate the chargeable and dischargeable current of a battery system having batteries connected in parallel by utilizing the estimated internal resistance. Further, by connecting the system in parallel via power converters, it becomes possible to control the charge and discharge current of the respective batteries, so as to prevent concentration of current to a battery having a low internal resistance, and to control the battery temperature constantly or to control the maximum temperature of the batteries.

Thereby, it becomes possible to draw out the maximum performance of the batteries and to realize long life of batteries.

Further, the present invention enables to improve the accuracy of estimated internal resistance in a battery system having batteries connected in parallel and in series by estimating the voltages and currents of the respective batteries based on the estimated internal resistance and to compare the values with the voltage and current sensor values used for estimation of the batteries.

The present invention provides a battery control system and method capable of computing the deterioration rates of batteries with high accuracy, thereby contributing to the manufacture, sales and maintenance of battery control systems.

Claims

What is claimed is: 1. A battery control system comprising: at least one battery; and a control circuit; characterized in comprising a sensor for detecting a battery state information of the battery; an internal resistance computation means for computing an internal resistance based on the battery state information from the sensor; an internal resistance retention means for retaining the internal resistance per temperature range of the battery; and a deterioration determination means for comparing a reference internal resistance per temperature range of the battery and a computed internal resistance, for determining a deterioration rate of the battery.

2. Thebattery control system according to claimi, wherein the deterioration deterininationmeans computes the internal resistance for every temperature range via the internal resistance retentionmeans, andcomputes the internal resistance for all temperature ranges to obtain the internal resistance of the battery which is compared with the reference internal resistance to obtain the deterioration rate.

3. The battery control system according to claim 2, comprising: a reference internal resistance table for storing the reference internal resistance corresponding to all temperature ranges; wherein the systemutilizes the reference internal resistance stored in the reference internal resistance table.

4. The battery control system according to claim 2, wherein the deterioration determinationmeans computes the internal resistance for every temperature range via the internal resistance retention means, performs computation for all the temperature ranges to obtain a central tendency of the measured internal resistance and a central tendency of the reference internal resistance of the battery, then the central tendency of the measured internal resistance is compared with the central tendency of the reference internal resistance to determine the deterioration rate.

5. The battery control system according to claims 2 and 3, wherein the internal resistance retention means retains the update time of the measured internal resistance of each temperature range.

6. The battery control system according to claim 4, wherein the deterioration determination means comprises a temperature range central tendency function for obtaining a plurality of temperature range central tendencies for each temperature range from the measured internal resistance in the internal resistance retention means, and a central tendency function for obtaining the central tendency of the internal resistance from the output of the temperature range central tendency function.

7. The battery control system according to claim 6, wherein the temperature range central tendency function and the central tendency function are functions for obtaining the average value.

8. The battery control system according to claim 6, wherein the central tendency function is a function for obtaining the central tendency via weight averaging corresponding to the number of internal resistances registered for each temperature range in the internal resistance retention means.

9. Thebatterycontrol systemaccordingtoclaim8, wherein the central tendency function is a function for obtaining the central tendency via weight averaging in which a weight of an old internal resistance is reduced corresponding to the update time of the measured internal resistance registered for each temperature range in the internal resistance retention means.

10. Thebatterycontrolsystemaccordingtoclaiml, wherein the system comprises a function to display a notice when resistances of a certain temperature range within the temperature ranges of the internal resistance retention means differ greatly compared to other temperature ranges.

11. A battery control method for controlling the battery comprising at least one battery, characterized in detecting a battery state information of the battery via a sensor; computing an internal resistance based on the battery state information; retaining the internal resistance for every temperature range of the battery; and computing a reference internal resistance per temperature range of the battery and a computed internal resistance are compared to determine a deterioration rate.

12. The battery control method according to claim 11, wherein after computing the internal resistance for every temperature range, the system computes the internal resistance for all temperature ranges to obtain the internal resistance of the battery, which is compared with the reference internal resistance to obtain the deterioration rate.

13. The battery control method according to claim 12, comprising: a reference internal resistance table for storing the reference internal resistance corresponding to all temperature ranges; wherein themethod utilizes the reference internal resistance stored in the reference internal resistance table.

14. The battery control method according to claim 12, wherein the internal resistance for every temperature range is computed, and thereafter, the internal resistance for all the temperature ranges is computed to obtain a central tendency of the measured internal resistance and a central tendency of the reference internal resistance of the battery, then the central tendency of the measured internal resistance is compared with the central tendency of the reference internal resistance to determine the deterioration rate.

15. The battery control methods according to claims 12 and 13, wherein the update time of the measured internal resistance is retained for each temperature range.

16. The battery control method according to claim 14, characterized in using a temperature range central tendency function for obtaining a plurality of temperature range central tendencies for each temperature range based on the measured internal resistance in the internal resistance retention means, and a central tendency function for obtaining the central tendency of the internal resistance from the output of the temperature range central tendency function.F). A battery control system comprising: at least one battery; and a control circuit; characterizedincomprisingasensor fordetectingabattery state information of the battery; an internal resistance computation means for computing an internal resistance based on the battery state information from the sensor; an internal resistance retention means for retaining the internal resistance for every temperature range of the battery; and a deterioration determination means for comparing a reference internal resistance for every temperature range of the battery and a computed internal resistance, and obtaining an estimated deterioration rate; wherein a warning signal is output when an estimated deterioration rate of a certain temperature range has a greater difference compared to the estimation values of other temperature ranges.

S

18. The battery control system according to claim 17, wherein when an estimated deterioration rate of a certain temperature range has a greater difference compared to the estimation values of other temperature ranges, operation is performed so that the temperature of the assembled battery does not reach said temperature range.

19. A battery control system in which more than two sets of an assembled battery composed of one or more batteries and a control circuit are connected, comprising: a sensor for detecting a battery state information of the battery; an internal resistance computation means for computing an internal resistance based on the battery state information from the sensor; and a deterioration determination means for comparing a reference internal resistance stored in advance and a computed internal resistance, so as to determine a deterioration rate of the battery.

20. The battery control system according to claim 19, wherein the assembled battery comprises at least two batteries connected in series; and if there is a deterioration rate exceeding a determined range from average with respect to the distribution of deterioration of the battery determined by the deterioration determination means, a re-computation of the deterioration rate is requested to the deterioration determination means that determined said deterioration rate.

21. The battery control system according to claim 20, wherein if it is determined once again that the deterioration rate as a result of re-computation exceeds the determined range from the average deterioration, the system requests a readjustment of the deterioration determination means or the sensor.

22. The battery control system according to claim 21, wherein if the deterioration rate determined by the deterioration determination means after the readjustment exceeds the determined range from the average deterioration rate once again, the system determines malfunction of the battery or the malfunction of the sensor.

23. The battery control system according to claim 19, wherein the assembled battery has at least two batteries connected in series; andIwhen a deterioration rate exceeding the determined range from the average exists with respect to the distribution of deterioration of the battery determined by the deterioration determinationmeans, the deterioration rate is corrected to fall within the determined range.

24. The battery control system according to claim 23, wherein the sensor includes a voltage sensor for detecting the voltage of the assembled battery; and when the voltage exceeds a determined range as a result of detection via the voltage sensor, the deterioration rate of the assembled battery is increased.

25. The battery control system according to claim 19, wherein the assembled battery has at least two batteries connected in parallel; the sensor includes a voltage sensor for detecting the voltage of the assembled battery and a current sensor for detecting the current of the assembled battery; the deterioration determination means determines the deterioration rate and the state of charge of the assembled battery; and an estimated voltage and estimated current of the assembled battery computed based on the determined deterioration rate and determined state of charge are compared with the measured values detected via the voltage sensor and the current sensor, and the deterioration rate is adjusted based on the compared result.

26. The battery control system according to claim 25, wherein if the difference between the predicted value and the measured value exceeds a predetermined value, the deterioration rate is adjusted based on the magnitude relation of the predicted value and the measured value.

27. The battery control system according to claim 26, wherein if the predicted value of voltage is greater than the measured value, the deterioration rate is reduced, and if the predicted value is smaller than themeasuredvalue, the deteriorationrate is increased.

2B. The battery control system according to claim 26, wherein if thepredictedvalueof current is greaterthanthemeasured value, the deterioration rate is increased, and if the predicted value is smaller than themeasuredvalue, thedeteriorationrate is reduced.

29. A battery control system having connected in parallel two or more sets of one or more batteries and a control circuit, wherein the control circuit estimates a deterioration rate of the battery and a permissible charge and discharge current capable of being charged and discharged, and based on the estimated deterioration rate andpermissible charge and discharge current, computes the current capable of being charged and discharged of the whole battery control system.

30. The battery control system according to claim 29, wherein the control circuit computes a charge and discharge current ratio flowing in each battery based on the estimated deterioration rate, and based on the computed charge and discharge current ratio and the permissible charge and discharge current of each battery, computes the current capable of being charged and discharged of the whole battery control system with respecttoeachbattery, andsetsthemiriimurnvalueofthecomputed current as the current capable of being charged and discharged of the whole battery control system.31. A battery control system having connected in parallel two or more sets of one or more batteries and a control circuit, comprising: a sensor for detecting a battery state information of the battery; and a power converting device for performing power conversion of the battery control state detected by the sensor; wherein the power converting device converts the voltage of the battery to a different voltage, and controls the current flowing in the battery.

31. The battery control system according to claim 31, wherein the control circuit adjusts the current flowing in the battery via the power converting device so that it equals the heating value of the battery of the whole battery control system.

32. The battery control system according to claim 31, wherein the control circuit adjusts the current flowing in the battery via the power converting device so that it equals a maximum heating value of the battery of the whole battery control system.

33. A battery control system substantially as any herein described with reference to and as shown in the accompanying drawings.

34. A battery control method substantially as any herein described with reference to the accompanying drawings.Amendments to the claims have been filed as follows: CLAIMS: 1. A battery control system comprising: at least one battery; and a control circuit; characterized in comprising a sensor for detecting a battery state information of the battery; an internal resistance computation means for computing an internal resistance based on the battery state information from the sensor; an internal resistance retention means for retaining the *:::: internal resistance per temperature range of the battery; and a deterioration determination means for comparing a S...reference internal resistance per temperature range of the S..battery and an internal resistance computed by the internal S..... * ,resistance computation means, for determining a deterioration rate of the battery.2. The battery control system according to claim 1, wherein the deterioration determination means computes the internal resistance for every temperature range via the internal resistance retention means, and from the measured internal resistance and the reference internal resistance for all temperature ranges obtains the deterioration rate by comparing the measured internal resistance of the battery with the reference internal resistance.3. The battery control system according to claim 2, comprising: a reference internal resistance table for storing the reference internal resistance corresponding to all temperature ranges; wherein the system utilizes the reference internal resistance stored in the reference internal resistance table.4. The battery control system according to claim 2, wherein the deterioration determination means computes the internal resistance for every temperature range via the internal resistance retention means, performs computation for all the temperature ranges to obtain a central tendency of the measured internal resistance and a central tendency of the reference **.* internal resistance of the battery, then the central tendency of * the measured internal resistance is compared with the central S...tendency of the reference internal resistance to determine the * deterioration rate.5. The battery control system according to claim 1, wherein the internal resistance retention means retains the update time of the measured internal resistance of each temperature range.6. The battery control system according to claim 4, wherein the deterioration determination means comprises a temperature range central tendency function for obtaining a temperature range central tendency for each temperature range from the measured internal resistance in the internal resistance retention means, and a central tendency function for obtaining the central tendency of the measured internal resistance from the output of the temperature range central tendency function.7. The battery control system according to claim 6, wherein the temperature range central tendency function and the central tendency function are functions for obtaining the average value.8. The battery control system according to claim 6, wherein the central tendency function is a function f or obtaining the central tendency via weight averaging corresponding to the i number of internal resistances registered for each temperature * range in the internal resistance retention means.S S S... ** .* .: 9. The battery control system according to claim 8, wherein the deterioration determination means computes the internal resistance for every temperature range via the internal resistance retention means, and from the measured internal resistance responding to an update time and the reference internal resistance for all temperature ranges obtains the deterioration rate by comparing the internal resistance of the battery with the reference internal resistance.10. The battery control system according to claim 1, where in the system comprises a function to display a notice when resistances of a certain temperature range within the temperature ranges of the internal resistance retention means differ greatly from resistances of other temperature ranges.11. A battery control method for controlling a battery system comprising at least one battery, characterized by the steps of Ci) detecting a battery state information of the battery via a sensor; (ii) computing an internal resistance based on the battery state information; * * S...(iii) retaining the internal resistance for every temperature range of the battery; and * 5'. S. * (iv) comparing a reference internal resistance per ***.::::; temperature range of the battery and an internal resistance * S. computed in step (ii), to determine a deterioration rate.12. The battery control method according to claim 11, where in after computing the internal resistance for every temperature range, the system obtains the deterioration rate from the internal resistance computed in step (ii) and the reference internal resistance for all temperature ranges by comparing the internal resistance computed in step (ii) with the reference internal resistance.13. The battery control method according to claim 12, comprising: a reference internal resistance table for storing the reference internal resistance corresponding to all temperature ranges; wherein the method utilizes the reference internal resistance stored in the reference internal resistance table.14. The battery control method according to claim 12, where in the internal resistance for every temperature range is computed, and thereafter, the internal resistance for all the S...temperature ranges is computed to obtain a central tendency of S...is the measured internal resistance and a central tendency of the *S S*.* * reference internal resistance of the battery, then the central *...tendency of the measured internal resistance is compared with the * central tendency of the reference internal resistance to determine the deterioration rate.15. The battery control method according to claims 12 and 13, wherein the update time of the measured internal resistance is retained for each temperature range.16. The battery control method according to claim 14, characterized in using a temperature range central tendency function for obtaining a temperature range central tendency for each temperature range based on the measured internal resistance in the internal resistance retention means, and a central tendency function for obtaining the central tendency of the measured internal resistance from the output of the temperature range central tendency function.17. A battery control system according to claim 1, wherein: the internal resistance retention means is arranged for retaining the internal resistance for every temperature range of the battery; and the deterioration determination means is arranged for * * ***.comparing a reference internal resistance for every temperature range of the battery and an internal resistance computed by the S....* internal resistance computation means, and obtaining an estimated deterioration rate; and wherein * a warning signal is output when the estimated deterioration rate of a certain temperature range differs greatly from the estimation values of the estimated deterioration rate of other temperature ranges.18. The battery control system according to claim 17, wherein when an estimated deterioration rate of a certain temperature range differs greatly from the estimation values of the estimated deterioration rate of other temperature ranges, operation is performed so that the temperature of the battery does not reach said temperature range.19. A battery control system in which more than two battery sets are connected, each set comprising an assembled battery composed of one or more batteries and a control circuit, wherein each set comprises a sensor for detecting a battery state information of the assembled battery; an internal resistance computation means for computing an internal resistance based on the battery state information from the sensor; and * * * ::..: a deterioration determination means f or comparing a reference internal resistance stored in advance and a computed **** internal resistance, so as to determine a deterioration rate of *.*.S.* the assembled battery. *... * * �S*S ** ** .: 20. The battery control system according to claim 19, wherein the assembled battery comprises at least two batteries connected in series; and if there is a deterioration rate exceeding a determined range from average with respect to the distribution of deterioration of the battery determined by the deterioration determination means, a re-computation of the deterioration rate is requested to the deterioration determination means that determined said deterioration rate.21. The battery control system according to claim 20, wherein if it is determined once again that the deterioration rate as a result of re-computation exceeds the determined range from the average deterioration, the system requests a readjustment of the deterioration determination means or the sensor.22. The battery control system according to claim 21, wherein if the deterioration rate determined by the deterioration determination means after the readjustment exceeds the determined * * S S. * range from the average deterioration rate once again, the system * S determines malfunction of the battery or the malfunction of the * S sensor.S..... * . *...23. The battery control system according to claim 19, * S. wherein the assembled battery has at least two batteries connected in series; and when a deterioration rate exceeding the determined range from the average exists with respect to the distribution of deterioration of the battery determined by the deterioration determination means, the deterioration rate is corrected to fall within the determined range.24. The battery control system according to claim 23, wherein the sensor includes a voltage sensor for detecting the voltage of the assembled battery; and when the voltage exceeds a determined range as a result of detection via the voltage sensor, the deterioration rate of the assembled battery is increased.25. The battery control system according to claim 19, where in the assembled battery has at least two batteries connected in parallel; the sensor includes a voltage sensor for detecting the * * * voltage of the assembled battery and a current sensor for **.* detecting the current of the assembled battery; * I 15 the deterioration determination means determines the * III..* 1 deterioration rate and the state of charge of the assembled *I*.battery; and ** * an estimated voltage and estimated current of the assembled battery computed based on the determined deterioration rate and determined state of charge are compared with the measured values detected via the voltage sensor and the current sensor, and the deterioration rate is adjusted based on the compared result.26. The battery control system according to claim 25, wherein if the difference between the estimated value and the measured value exceeds a predetermined value, the deterioration rate is adjusted based on the magnitude relation of the estimated value and the measured value.27. The battery control system according to claim 26, wherein if the predicted value of voltage is greater than the measured value, the deterioration rate is reduced, and if the predicted value is smaller than the measured value, the deterioration rate is increased.28. The battery control system according to claim 26, wherein S.. * .... if the predicted value of current is greater than the * ..measured value, the deterioration rate is increased, and if the S... * Ipredicted value is smaller than the measured value, the S..... * Sdeterioration rate is reduced. * **. * S S... *I ** *: 29. A battery control system having connected in parallel two or more battery sets, each set comprising one or more batteries and a control circuit, wherein the control circuit estimates a deterioration rate of the batteries and a permissible charge and discharge current capable of being charged and discharged, and based on the estimated deterioration rate and permissible charge and discharge current, computes the current capable of being charged and discharged of the whole battery control system.30. The battery control system according to claim 29 wherein the control circuit computes a ratio of the charge and discharge current flowing in each battery based on the estimated deterioration rate, and, based on the computed ratio of charge and discharge current and the permissible charge and discharge current of each battery, computes the current capable of being charged and discharged of the whole battery control system with respect to each battery, and sets the minimum value of the io computed current as the current capable of being charged and discharged of the whole battery control system. S... * S* ** .31. A battery control system having connected in parallel * S two or more battery sets, each set comprising one or more I. batteries and a control circuit, comprising: *S.... * .wherein each set comprises ::::; a sensor for detecting a battery state information of the * battery; and a power converting device for performing power conversion of the battery state detected by the sensor; wherein the power converting device converts the voltage of the battery to a different voltage, and controls the current flowing in the battery.32. The battery control system according to claim 31, where in the control circuit adjusts the current flowing in the battery via the power converting device so that the heating value of the battery equals the heating value when the battery is new.33. A battery control system substantially as any herein described with reference to and as shown in the accompanying drawings.34. A battery control method substantially as any herein described with reference to the accompanying drawings. * . S S. S * . . * S 5.5S SSSS* * S **.. * S *.. *. . S* **