JP4890977B2 - Battery deterioration calculation device - Google Patents

Description

  The present invention relates to a battery deterioration calculation device that calculates a deterioration state of a battery that supplies power to a load.

  As a power source for an electric vehicle using an electric motor as a drive source or a hybrid vehicle using an electric motor and an engine as a drive source, a storage battery such as a secondary battery or an electrochemical capacitor, that is, a battery is used. For example, a secondary battery such as a lithium ion battery is used as a battery of a hybrid vehicle. When the motor torque is transmitted to the drive wheels, electric power is supplied from the battery to the electric motor, and the battery is driven by the engine. Is charged by the power from the generator.

  When the battery is repeatedly charged and discharged, the deterioration progresses due to a change with time or aging, and when the deterioration progresses, the internal resistance of the battery, that is, the impedance increases, and the charge capacity decreases. Therefore, as the deterioration progresses, the dischargeable capacity that can be discharged from the fully charged state gradually decreases. Therefore, in order to surely grasp the replacement time of the battery, the deterioration degree of the battery, that is, SOH (State of Health) is monitored.

As battery deterioration progresses, the internal resistance increases and the current capacity decreases, so the battery deterioration is calculated by resistance deterioration calculation that detects internal resistance and capacity deterioration calculation that detects current capacity. is there. In order to detect the deterioration of the battery, conventionally, a method of calculating the resistance deterioration has been mainstream (see Patent Documents 1 to 4).
JP-A-8-214469 JP 2001-16787 A JP 2003-177164 A JP 2004-354050 A

  Patent Document 1 describes a calculation method for detecting the internal resistance of a battery by operating a starter switch to detect a battery voltage during cranking by the starter in order to calculate the deterioration degree of the battery. When the resistance exceeds a set value, it is determined that the battery has deteriorated. In this method, the internal resistance is detected by regarding the starter current as a predetermined fixed value, and it is difficult to calculate an accurate battery deterioration value. In Patent Document 2, if the battery is not deteriorated, the voltage fluctuation on the charging side is smoothed by the battery. Therefore, by comparing the voltage fluctuation on the charging side due to the lip noise and the voltage fluctuation on the discharging side, A deterioration detection apparatus that determines deterioration is described. In this detection device, the calculation of the internal resistance of the battery is limited at the time of full charge, and when combined with voltage fluctuation, the accuracy of deterioration determination is improved, but in a hybrid vehicle, the chance of full charge is limited. It is difficult to grasp the deterioration situation in a timely manner.

  In Patent Document 3, the internal resistance of the battery is calculated by using the inrush current of the load as in Patent Document 1, and the polarization resistance calculated from the battery discharge current and the terminal voltage (measured in advance). The deterioration value of the battery is calculated by multiplying the deterioration value component of the value (approximate expression is used). However, the calculation accuracy is greatly affected by the battery temperature and the load fluctuation of the characteristic variation. In Patent Document 4, the charge / discharge amount at the time of non-deterioration is calculated from the charge / discharge amount obtained by current integration and the open-circuit voltage value based on the charge / discharge amount between the full charge open voltage at the time of non-deterioration and the discharge end open-circuit voltage. The difference is calculated as a deterioration value. However, in order to ensure the calculation accuracy of the open circuit voltage, the degradation mode of the active material and the change component due to voltage hysteresis are taken into account, both of which are based on measured values, so the usage environment is significantly different from when acquiring basic data Can not cover.

  An object of the present invention is to make it possible to detect battery deterioration with high accuracy.

  Another object of the present invention is to make it possible to detect battery deterioration with high accuracy based on the rate of change in current capacity of the battery.

  The battery deterioration calculation apparatus according to the present invention includes a voltage detection unit that detects a terminal voltage of the battery, a current detection unit that detects a charge / discharge current of the battery, the terminal voltage detected by the voltage detection unit, and the current A first remaining capacity calculating means for calculating a remaining capacity based on an open-circuit voltage from a charge / discharge current detected by the detecting means and an open-circuit voltage of the battery estimated from an impedance of an equivalent circuit of the battery; and the current detecting means A second remaining capacity calculating means for calculating the remaining capacity based on the current integration by integrating the detected charging / discharging current, and the first remaining capacity and the second remaining capacity according to the use status of the battery. A combined remaining capacity calculating means for calculating a combined remaining capacity by weighted synthesis using weights set in accordance with a weight, and a change amount of the remaining capacity based on current integration A capacity change rate calculating means for calculating a current capacity change rate based on the amount of change in the combined remaining capacity, and that the degree of deterioration of the battery is greater than a set value when the current capacity change rate falls below a predetermined value. And a deterioration determining means for determining.

In the battery deterioration calculation apparatus according to the present invention, the deterioration degree is calculated when the charge / discharge current continues for a predetermined time within a predetermined range.

In the battery deterioration calculation apparatus according to the present invention, the deterioration degree is calculated when the temperature of the battery continues for a predetermined time within a predetermined range.

In the battery deterioration calculation device according to the present invention, the current capacity change rate is obtained from the change amount of the remaining capacity based on the current integration and the change amount of the combined remaining capacity, and the current capacity change rate becomes a predetermined value or less. The deterioration degree is sometimes calculated .

In degradation arithmetic unit battery of the present invention, the current rate of change in capacitance is calculated a plurality of times at predetermined time intervals, and calculates the degradation degree based on the average value of a plurality of said current rate of change of capacity .

In degradation arithmetic unit battery of the present invention, the weighted average of the current rate of change in capacitance, and calculates the degradation degree based on the weighted average value.

In degradation arithmetic unit battery of the present invention is characterized warning display it when the deterioration degree is exceeded the value corresponding to the preset battery life.

In degradation arithmetic unit battery of the present invention, the remaining capacity and the combined remaining capacity based on the current integration, and updates each when calculating the deterioration degree as the initial value.

  In the battery deterioration calculation device according to the present invention, the remaining capacity based on the current integration and the combined remaining capacity, which are respectively calculated under a state where the current value of the battery is almost zero for a predetermined time, are initially set. It is characterized by being updated as a value.

In the battery deterioration calculation apparatus according to the present invention, the current capacity change rate used for calculating the degree of deterioration is updated as an initial value.

  In the battery deterioration calculation apparatus according to the present invention, the current capacity change rate is updated as an initial value when the system is terminated.

  According to the present invention, the amount of change in the remaining capacity based on the current integration changes due to the deterioration of the battery, but since the parameter is limited and does not depend on the voltage change, the deterioration is determined based on the amount of change in the remaining capacity based on the current integration. By doing so, it is possible to obtain the degree of deterioration of the battery with high accuracy without affecting the determination of the degree of deterioration even if a load fluctuation of the battery occurs.

  Since the battery deterioration is calculated by using the amount of change in the combined remaining capacity obtained by weighting the remaining capacity based on the current integration and the remaining capacity based on the estimation of the open circuit voltage, the degree of deterioration of the battery can be obtained with high accuracy. .

  By setting the deterioration calculation condition, the deterioration determination accuracy can be increased.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing a drive control system for a hybrid vehicle. This hybrid vehicle (HEV) has an engine 11 and a generator motor 12 as drive sources, and the generator motor 12 functions as a vehicle drive source. And a function as a generator, that is, a generator. The generator motor 12 has a rotor 12a connected to the crankshaft of the engine 11, and a stator 12b that is disposed outside the rotor 12a and is fixed to the case 13. The rotor 12a is connected to the input shaft 16 of the transmission 15 via the torque converter 14, and the engine torque and the motor torque are transmitted to the input shaft 16 of the transmission, and the engine torque is transmitted to the rotor 12a during power generation. The output shaft 17 of the transmission 15 is connected to the left and right drive wheels 19a and 19b via a differential mechanism 18.

  The hybrid vehicle shown in FIG. 1 can transmit the drive torque of one or both of the engine 11 and the generator motor 12 to the drive wheels. The engine 11 can be driven by the engine 11 to charge the battery. However, the vehicle can be driven by the engine 11. For example, the engine 11 can be driven as a main power source when the vehicle is traveling, and the assist torque of the generator motor 12 can be supplementarily applied to the vehicle when starting or accelerating. The generator motor 12 functions as a generator during braking, and can collect regenerative energy and charge the battery.

  As shown in FIG. 1, the drive control system includes a hybrid control unit (HEVECU) 21 having a microprocessor and the like. The hybrid control unit 21 sends a control signal to an engine control unit (engine ECU) 22 that sends a drive signal to the engine 11, an inverter 23 that sends a drive signal to the generator motor 12, and a warning lamp 24, and automatic shifting Control signals are also sent to various devices such as a machine. The battery 25 is a lithium ion secondary battery, and is configured by connecting a plurality of battery packs in which a plurality of cells are sealed in series. A voltage sensor 26 that measures the terminal voltage V of the battery 25, a current sensor 27 that measures the charge / discharge current I of the battery 25, and a temperature sensor 28 that measures the temperature of the battery 25, that is, the cell temperature T, are respectively supplied to the power supply control unit (battery). ECU) 29.

  Similarly to the hybrid control unit 21, the power supply control unit 29 includes a microprocessor CPU that calculates control signals, a ROM that stores control programs, arithmetic expressions, map data, and the like, a RAM that temporarily stores data, and the like. And comprises first and second remaining capacity calculating means, capacity change rate calculating means, and deterioration determining means. The power supply control unit 29 calculates the remaining capacity SOC of the battery 25 and the deterioration degree SOH of the battery 25 at predetermined time intervals based on the signals of the sensors 26 to 28 and sends a signal to the hybrid control unit 21.

  FIG. 2 is a block diagram showing an algorithm for calculating the battery remaining capacity SOC. As described in Japanese Patent Application Laid-Open No. 2005-201743, the remaining capacity SOCc is determined based on current integration based on a signal from the current sensor 27. The remaining capacity SOCv is calculated based on the open-circuit voltage based on the estimated value of the battery open-circuit voltage based on the signal from the voltage sensor 26 based on the signal from the voltage sensor 26, and the combined remaining capacity SOC synthesized by weighting each is calculated. Output as capacity.

The remaining capacity SOCc based on the current integration for obtaining the combined remaining capacity SOC is calculated by the following equation (1).
SOCc = SOC (t-1) − (∫ (I × ηdt) / (Ah × 3600) × 100 (1)

However, SOC (t-1) is a value of the composite remaining capacity SOC obtained one calculation cycle before, and is a base value of current integration, and is shown as a delay operator Z- ¹ in FIG. Yes. In equation (1), η is the battery efficiency, and Ah is the battery current capacity.

  FIG. 3 is a characteristic diagram showing the relationship between the battery current capacity reduction rate and the battery temperature T, and shows the ratio of the current capacity when the current capacity Ah at a temperature of 25 ° C. is 1. A table of current capacity reduction rates corresponding to this characteristic diagram is stored in the ROM, and the current capacity based on the temperature T detected by the temperature sensor 28 by referring to the stored current capacity reduction rate table. Ah is required.

  On the other hand, if the open circuit voltage V0 is obtained, there is a certain relationship between the open circuit voltage V0 and the current capacity Ah. Therefore, the remaining capacity based on the open circuit voltage V0 can be obtained from map data or an arithmetic expression. However, even if the terminal voltage V is measured when a current is flowing through the battery, it does not mean that the open circuit voltage V0 has been detected. Therefore, the open circuit voltage V0 is estimated from the terminal voltage V of the battery 25 measured by the voltage sensor 26, and the remaining capacity SOCv based on the open circuit voltage is calculated based on the estimated value.

  FIG. 4 is an equivalent circuit model diagram of the battery for obtaining the remaining capacity SOCv of the battery based on the estimated value of the open circuit voltage V0. This equivalent circuit is an equivalent circuit model in which parameters of resistance components R1 to R3 and capacitance components C1, CPE1, and CPE2 (where CPE1 and CPE2 are double layer capacitance components) are combined in series and in parallel. Each parameter is determined by curve fitting a well-known Cole-Cole plot at.

The impedance Z obtained from these parameters varies greatly depending on the battery temperature, the electrochemical reaction rate, and the frequency component of the charge / discharge current. Therefore, as a parameter for determining the impedance Z, the moving average value of the current I per unit time is adopted as the replacement of the frequency component, the impedance measurement is performed on the condition of the moving average value of the current I and the temperature T, and the data After the accumulation, a table of impedance Z is created based on the temperature T and the moving average value of the current I per unit time, and stored in the ROM. Then, the impedance Z is obtained using this impedance table, and the estimated value of the open-circuit voltage V0 is obtained from the impedance Z, the measured terminal voltage V and the current I using the following equation (2).
V = V0-I · Z (2)

  There are merits and demerits in the remaining capacity SOCc obtained by the expression (1) by integrating the current I and the remaining capacity SOCv by the estimation of the open circuit voltage V0 obtained by the expression (2) based on the terminal voltage V. The remaining capacity SOCc due to current integration tends to accumulate errors, and is particularly resistant to load fluctuations such as inrush currents, while the error during high load continuation is large. On the other hand, the remaining capacity SOCv based on the open-circuit voltage estimation can be obtained as an almost accurate value during normal use, but the value may change rapidly when the load fluctuates greatly in a short time. is there.

Therefore, the remaining capacity SOCc obtained by integrating the current I and the remaining capacity SOCv obtained from the estimated value of the battery open-circuit voltage are weighted by a weight (weighting coefficient) w that is changed as needed according to the battery usage status. By synthesizing, the disadvantages of both remaining capacities can be canceled and the mutual advantages can be maximized. The remaining capacity SOC after the synthesis is obtained by the following formula (3).
SOC = w · SOCc + (1-w) · SOCv (3)

  The weight w is a value between w = 0 and 1, and is determined using a parameter that can accurately represent the current battery usage status. As the parameter, it is possible to use a current change rate ΔI per unit time, a deviation between the remaining capacities SOCc and SOCv, and the like.

  The rate of change in current per unit time directly reflects the load fluctuation of the battery, but the mere rate of change in current is affected by a sudden change in current that occurs instantaneously. Therefore, in order to prevent the influence of a change in current that occurs instantaneously, a current change rate subjected to processing such as a simple average, a moving average, and a weighted average of a predetermined number of samplings is used. In particular, considering the current delay, it is preferable to determine the weight w using a moving average that can appropriately reflect the past history without excessively changing the charge / discharge state of the battery.

  FIG. 5 is an explanatory diagram showing an example of a weight table. In the case of the weight w shown in FIG. 5, the corrected current change rate KΔI / Δt obtained by correcting the temperature of the moving average value of the current I is used as a parameter. As shown in FIG. 5, the smaller the corrected current change rate KΔI / Δt, that is, the smaller the load fluctuation of the battery, the smaller the value of the weight w and the smaller the weight of the remaining capacity SOCc due to current integration. ing.

  On the other hand, the impedance table described above is a table in which the value of the equivalent impedance Z is stored using the corrected current change rate KΔI / Δt and the temperature T as parameters, and when the corrected current change rate KΔI / Δt is the same, The impedance Z increases as T decreases. At the same temperature, the impedance Z tends to increase as the corrected current change rate KΔI / Δt decreases.

  As described above, the moving average value of the current I is also used as a parameter for determining the weight w and the impedance Z and facilitates the calculation of the weight w and the impedance Z. However, the internal impedance of the battery increases as the temperature decreases. Therefore, the weight w and the impedance Z are directly determined using the corrected current change rate KΔI / Δt obtained by correcting the temperature of the moving average value of the current I as described above.

  By determining the weight w based on the moving average value of the current I, when the moving average value of the current I is large, the weight of the current integration is increased and the weight of the open circuit voltage estimation is lowered, and the influence of the load fluctuation is integrated with the current. Therefore, the vibration at the time of estimating the open circuit voltage can be prevented. Conversely, when the moving average value of current I is small, the effect of error accumulation during current integration is avoided by reducing the current integration weight and increasing the open-circuit voltage estimation weight. The remaining capacity can be calculated.

  The moving average of the current I becomes a low-pass filter for the high-frequency component of the current, and the filtering of the moving average can remove the spike component of the current that occurs due to load fluctuations during traveling without promoting the delay component. As a result, the battery state can be grasped more accurately, the disadvantages of both the remaining capacities SOCc and SOCv can be canceled to maximize the mutual advantages, and the estimation accuracy of the remaining capacities can be greatly improved.

  In the present invention, the amount of change (ΔSOCc) of the remaining capacity SOCc based on the current integration within a predetermined time and the amount of change (ΔSOC) of the combined remaining capacity SOC within the same time as the predetermined time are calculated. A current capacity change rate σ (ΔSOCc / ΔSOC) is obtained from the change amount.

In order to obtain the amount of change in the remaining capacity SOCc within a predetermined time, the remaining capacity SOCc before and after elapse of the predetermined time is calculated by the following equation (1a).
SOCc = SOCc (0) − (∫ (I × ηdt) / (Ah × 3600) × 100 (1a)

  The initial value SOCc (0) in the equation (1a) is different from the base value SOC (t−1) in the equation (1), and the remaining capacity calculated by the current integration without using the combined remaining capacity as the base value. The value is the initial value. The initial value SOCc (0) is obtained from the open circuit voltage V0 when the system is started, that is, when the starter key of the vehicle is turned on. At the time of system startup, the current I is zero, the terminal voltage V matches the open circuit voltage, and the remaining capacity SOCc based on the current integration is calculated with the remaining capacity obtained from the open circuit as a table based on the initial value SOCc (0). The

  On the other hand, in order to obtain the amount of change in the composite remaining capacity SOC, the composite remaining capacity SOC before and after the elapse of a predetermined time is calculated using the value of the composite remaining capacity SOC before one calculation cycle as a base value by the above-described equation (1).

  FIG. 6 is a characteristic diagram showing the relationship between the current capacity change rate σ and the impedance change amount τ. These are one-dimensional relationships, and when the current capacity change rate σ becomes a predetermined value σs or less, the battery It can be determined that the degree of degradation SOH has advanced beyond a predetermined value.

  FIG. 7 and FIG. 8 are flowcharts showing an algorithm of the battery deterioration calculation procedure, which is executed at a cycle of about 0.1 seconds. The measured values from the voltage sensor 26, current sensor 27, and temperature sensor 28 shown in FIG. 1 are read in step S1. In step S2, a current capacity table corresponding to a characteristic diagram showing the relationship between the battery temperature T and the current capacity Ah is read as shown in FIG. 3, and the current capacity Ah is calculated based on the value of the temperature T. . Based on the values of the current capacity Ah and the current I, the remaining capacity SOCc based on the current integration is calculated in step S3 by the above equation (1). In this calculation, it is necessary to set the combined remaining capacity one cycle before as the base value SOC (t−1), and the base value stored in the memory is used. However, at the time of starting the system, the value of the remaining capacity obtained from the open circuit voltage V0 can be used as the base value.

  In step S4, the above-described corrected current change rate KΔI / Δt is calculated, and the impedance Z is calculated in step S5 based on KΔI / Δt and the temperature T from the above-described impedance table. Thus, an estimated value of the open circuit voltage V0 is obtained from the impedance Z, the current I, and the terminal voltage V, and the remaining capacity SOCv based on the estimation of the open circuit voltage is calculated in step S6. In step S7, the weight w is calculated by the weight table shown in FIG. 5, and in step S8, the combined remaining capacity SOC is calculated by the above-described equation (3), and the calculated combined remaining capacity SOC is stored in the memory. The

  Next, when calculating the deterioration degree SOH of the battery, first, it is determined in step S9 whether or not the calculation condition (1) for the deterioration degree SOH is satisfied.

  The calculation condition (1) is that the current I is in the range of −Ia ≦ I ≦ Ib where the current I is near zero and the battery temperature T is within the predetermined range (Ta ≦ T ≦ Tb). Whether or not it continues is a condition. When this calculation condition is satisfied, the remaining capacity SOCc is calculated in step S10 based on the above formula (1a) to be the first remaining capacity SOCc (1). Further, the combined remaining capacity SOC calculated in step S8 under the condition that the calculation condition (1) is satisfied is set as the first combined remaining capacity SOC (1). These first calculated values SOCc (1) and SOC (1) are stored in the memory. For example, −Ia can be −3 A, Ib can be 3 A, Ta can be 20 ° C., Tb can be 60 ° C., and time ta can be several seconds. Thus, since the respective remaining capacities SOCc (1), SOCc (2), SOC (1), and SOC (2) are calculated when a predetermined calculation condition is satisfied, the calculation of the degree of deterioration is made high. Can be done with precision.

  Next, in step S11, it is determined whether or not the condition (2) for calculating the deterioration degree SOH is satisfied.

  The calculation condition (2) is that a predetermined time tb has elapsed since the first calculated values (SOCc (1) and SOC (1)) were calculated, and the battery temperature T during the elapsed time tb is predetermined. In the range (Ta ≦ T ≦ Tb), and the condition that −Ia ≦ I ≦ Ib where the current I is near zero continues for a predetermined time tc or more. When this calculation condition (2) is satisfied, the remaining capacity SOCc is calculated in step S12 based on the above equation (1a) to obtain the second remaining capacity SOCc (2). Further, the combined remaining capacity SOC calculated in step S8 under the condition that the calculation condition (2) is satisfied is set as the second combined remaining capacity SOC (2). These second calculated values SOCc (2) and SOC (2) are stored in the memory. For example, tb is set to about several tens of seconds, and tc is set to about several seconds.

  Next, in step S13, a change amount (ΔSOCc) of the remaining capacity, which is a difference between the first remaining capacity SOCc (1) and the second remaining capacity SOCc (2) based on the accumulated electric power, is calculated. In step S14, the amount of change (ΔSOC) in the combined remaining capacity, which is the difference between the first combined remaining capacity SOC (1) and the second combined remaining capacity SOC (2), is calculated. The respective combined remaining capacities are obtained by weighting the current accumulated remaining capacities obtained by using the value of the composite remaining capacities SOC as a base value according to the equation (3) and the remaining capacities estimated by the open circuit voltage.

  In step S15, the current capacity change rate σ is obtained from the ratio between the two amounts of change (ΔSOCc / ΔSOC). In step S16, a weighted average value σav of the current capacity change rate σ is calculated. The weighted average value σav is obtained by the following formula.

σav = (1−a) × σav0 + a × σ
However, 0 <a <1 (for example, a = 1/4), σav0 is the previously calculated σav, and the initial value of σav0 is 1.

  By determining the degree of deterioration by obtaining a weighted average value of the current capacity change rate σ, it is possible to improve the deterioration determination accuracy. In order to increase the deterioration determination accuracy, the determination accuracy can be improved by calculating the current capacity change rate σ a plurality of times every predetermined time and performing the deterioration determination by the average value of the plurality of current capacity change rate values. .

  In step S17, SOCc (2) is stored in the memory as SOCc (1), SOC (2) is stored in the memory as SOC (1), and the weighted average value σav of the current capacity change rate is stored in the memory in step S18. Store. By using the weighted average value σav stored in the memory as an initial value for the next calculation, it is possible to improve the degradation determination accuracy. However, as the timing for storing the initial value, the weighted average value at the end of the system may be updated.

Next, in step S19, it is determined whether or not the weighted average value σav of the current capacity change rate is equal to or less than the predetermined value σs, that is, whether or not the battery deterioration degree SOH is greater than the predetermined value. When it is determined in step S19 that the weighted average value σav of the current capacity change rate is equal to or less than the predetermined value σs, the warning lamp 24 shown in FIG. 1 is turned on. On the other hand, if NO is determined in step S19, it is determined in step S21 whether or not the warning lamp 24 has already been turned on. If the warning lamp 24 has already been turned on, the current capacity change rate is temporarily determined . Even if the weighted average value σav is equal to or greater than the predetermined value σs, the warning lamp 24 is turned on.

  Note that the memory may be updated so that the value of the remaining capacity SOCc when the degree of deterioration is determined is used as the initial value for calculating the expression (1a).

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, the embodiment is a case where the present invention is applied to determine deterioration of a battery mounted on a vehicle as a power source of a hybrid vehicle, but the present invention is also used to determine deterioration of a battery used for a power source of an electric vehicle. In addition to being applicable, the present invention can be applied to determine the deterioration of various batteries such as secondary batteries and electrochemical capacitors.

It is the schematic which shows the drive control system of a hybrid vehicle. It is a block diagram which shows the algorithm of the calculation system of battery remaining capacity. It is a characteristic diagram which shows the relationship between the current capacity fall rate of a battery, and the temperature of a battery. It is an equivalent circuit model diagram of a battery for obtaining the remaining capacity of the battery based on the estimated value of the open circuit voltage. It is explanatory drawing which shows an example of a weight table. It is a characteristic diagram which shows the relationship between a current capacity change rate and an impedance change amount. It is a flowchart which shows the algorithm of the deterioration calculation procedure of a battery. It is a flowchart which shows the algorithm of the deterioration calculation procedure of a battery.

Explanation of symbols

25 Battery 26 Voltage sensor (voltage detection means)
27 Current sensor (current detection means)
28 Temperature sensor (temperature detection means)
29 Power supply control unit

Claims (11)

Voltage detection means for detecting the terminal voltage of the battery;
Current detection means for detecting a charge / discharge current of the battery;
The remaining capacity based on the open circuit voltage is calculated from the terminal voltage detected by the voltage detection unit, the charge / discharge current detected by the current detection unit, and the open circuit voltage of the battery estimated from the impedance of the equivalent circuit of the battery. First remaining capacity calculating means;
Second remaining capacity calculating means for calculating the remaining capacity based on the current integration by integrating the charge / discharge current detected by the current detecting means;
A combined remaining capacity calculating means for calculating a combined remaining capacity by weighting and combining the first remaining capacity and the second remaining capacity using a weight set according to a use state of the battery;
Capacity change rate calculating means for calculating the current capacity change rate based on the change amount of the remaining capacity based on the current integration and the change amount of the combined remaining capacity;
A battery deterioration calculation device, comprising: a deterioration determination unit that determines that the degree of deterioration of the battery is greater than a set value when the current capacity change rate is equal to or less than a predetermined value. 2. The battery deterioration calculation device according to claim 1, wherein the deterioration degree is calculated when the charge / discharge current continues for a predetermined time within a predetermined range. 3. The battery deterioration calculation device according to claim 1, wherein the deterioration degree is calculated when the temperature of the battery continues for a predetermined time within a predetermined range. 4. The battery deterioration calculation device according to claim 1, wherein a current capacity change rate is obtained from a change amount of a remaining capacity based on the current integration and a change amount of the combined remaining capacity, and the current capacity is determined. A battery deterioration calculation device, characterized in that the deterioration degree is calculated when the rate of change becomes a predetermined value or less . In degradation arithmetic unit battery according to any one of claims 1 to 4, the current rate of change in capacitance is calculated a plurality of times at predetermined time intervals, the deterioration on the basis of the average value of a plurality of said current rate of change of capacity A battery deterioration calculation device characterized by calculating a degree. In degradation arithmetic unit battery according to any one of claims 1 to 5, wherein the current capacity change rate is a weighted average, the deterioration of the battery and calculates the degradation degree based on the weighted average value Arithmetic unit. In degradation arithmetic unit battery according to any one of claims 1 to 6, the battery characterized by warning display it when the deterioration degree is exceeded the value corresponding to the preset battery life Deterioration arithmetic unit. The battery deterioration calculation device according to any one of claims 1 to 7, wherein when the deterioration degree is calculated , the remaining capacity based on the current integration and the combined remaining capacity are updated as initial values, respectively. A battery deterioration calculation device characterized by:   The battery deterioration calculation device according to any one of claims 1 to 7, wherein the remaining current based on the current integration calculated under a state in which a state in which the current value of the battery is substantially zero continues for a predetermined period of time is provided. A battery deterioration calculation device, wherein the battery capacity and the combined remaining capacity are updated as initial values. 10. The battery deterioration calculation device according to claim 1, wherein the current capacity change rate used for calculating the degree of deterioration is updated as an initial value. .   11. The battery deterioration calculation device according to claim 10, wherein the current capacity change rate is updated as an initial value when the system ends.

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