JP2017116522A - Deterioration estimation method and deterioration estimation circuit for charging type battery, and electronic equipment and automobile using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve estimation accuracy of a deterioration in a battery.SOLUTION: In a deterioration estimation circuit 500 of a battery 102, a cycle detection part 502 detects that the battery 102 has been charged/discharged by a predetermined charge amount on the basis of a Coulomb count value obtained by integrating charging/discharging currents of the battery 102. A temperature detection circuit 504 monitors a temperature of the battery 102. A deterioration calculation part 506 changes an index X indicating a deterioration in the battery 102 by a change amount ΔX corresponding to a temperature T measured in a period when the predetermined charge amount is charged/discharged each time the charging/discharging of the predetermined charge amount is detected.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a battery management system.

  Various battery-powered electronic devices such as mobile phone terminals, digital cameras, tablet terminals, portable music players, portable game devices, and notebook computers have built-in rechargeable batteries (secondary batteries). Electronic circuits such as a CPU (Central Processing Unit) that performs system control and signal processing, a liquid crystal panel, a wireless communication module, and other analog and digital circuits operate with power supplied from a battery.

FIG. 1 is a block diagram of a battery-driven electronic device. The electronic device 900 includes a battery 902 and a charging circuit 904 that charges the battery 902. The charging circuit 904 receives a power supply voltage V _ADP from an external power adapter or USB (Universal Serial Bus) and charges the battery 902.

A load 908 is connected to the battery 902. The current _BAT flowing through the battery 902 is a difference between the charging current I _CHG from the charging circuit 904 and the load current (discharge current) I _LOAD flowing through the load 908.

  It is known that the battery 902 deteriorates every time charging / discharging is repeated. Specifically, the deterioration of the battery 902 appears as a decrease in its capacity. In order to estimate the deterioration of the battery 902, the electronic device 900 is provided with a deterioration estimation function. The deterioration estimation circuit 920 that estimates the deterioration of the battery may be integrated with a remaining amount detection circuit 906 that detects the remaining amount of the battery (charging state: SOC).

  The remaining amount detection circuit 906 is also referred to as a fuel gauge IC (Integrated Circuit). There are two main methods for detecting the remaining amount of the battery by the remaining amount detection circuit 906: (1) voltage method and (2) coulomb count method (charge integration method). The remaining amount detection circuit 906 may be built in the charging circuit 904.

  In the voltage method, an open circuit voltage (OCV) of a battery is measured in an open state (no load state), and the remaining amount is estimated from the correspondence relationship between the OCV and the SOC. OCV cannot be measured unless the battery is unloaded and in a relaxed state, and therefore it cannot be accurately measured during charge / discharge.

  In the coulomb counting method, the charge current flowing into the battery and the discharge current flowing out from the battery (hereinafter collectively referred to as charge / discharge current) are integrated, and the remaining amount is estimated by calculating the charge charge amount and the discharge charge amount to the battery. . According to the coulomb counting method, unlike the voltage method, the remaining amount can be estimated even during a battery usage period in which an open voltage cannot be obtained.

The remaining amount detection circuit 906 in FIG. 1 estimates the remaining amount of the battery 902 by the coulomb count method. The remaining amount detection circuit 906 includes a coulomb counter circuit 910 and an SOC calculation unit 912. Coulomb counter circuit 910 detects current I _{BAT of} battery 902 and integrates it. A coulomb count value (hereinafter, cumulative coulomb count value ACC) generated by the coulomb counter circuit 910 is expressed by the following equation.
ACC = ∫I _BAT dt
Strictly speaking, the battery current I _BAT is sampled discretely in time and calculated by the following equation. Δt represents a sampling period.
ACC = Σ (Δt × I _BAT )
This integration (integration) is performed, for example, with the current I _BAT flowing out from the battery 902 as positive and the current I _BAT flowing into the battery 902 as negative.

The SOC calculation unit 912 calculates the SOC of the battery 902 based on the ACC value. The following formula is used for the calculation of the SOC.
SOC [%] = (CC _FULL− ACC) / CC _FULL × 100
CC _FULL indicates the amount of charge (coulomb count capacity value) stored in the battery 902 in the fully charged state, and this corresponds to the capacity of the battery 902.

The charge / discharge cycle detection unit 922 of the deterioration estimation circuit 920 detects use corresponding to one charge / discharge cycle based on data generated by the coulomb counter circuit 910. Degradation calculator 924, the charge-discharge cycle detection section 922 each time it detects a charge-discharge cycle, increments the charge and discharge cycles _{CYC CD.} The charge / discharge cycle number CYC _CD represents the degree of deterioration of the battery 902. The number of charge / discharge cycles CYC _CD can be used for an alert indicating the battery life.

Further, based on the charge / discharge cycle detection unit 922 and the number of charge / discharge cycles CYC _CD , the Coulomb count capacity value (battery capacity) CC _FULL used in the SOC calculation unit 912 is corrected.

US Pat. No. 9,035,616B2

As a result of studying the deterioration estimation circuit 920 in FIG. 1, the present inventor has come to recognize the following problems. Figure 2 is a diagram showing a deterioration degree of the relationship between charge and discharge cycles CYC _CD and battery. The degree of deterioration represents the deteriorated capacity CC _FULL with the rated capacity as 100%. As shown in FIG. 2, the deterioration degree charge-discharge cycle number CYC _CD relationship varies with conditions such as temperature of the battery. For example, when the battery temperature is 45 ° C., the deterioration proceeds faster than when the temperature is 25 ° C. On the other hand, the deterioration calculator 924 defines at predetermined conditions (such as a predetermined temperature), the relationship between the deterioration degree charge-discharge cycle number CYC _CD (the degradation characteristics). Therefore, when the predetermined condition deviates from the actual battery use condition, the error of the deterioration estimated value increases.

  The present invention has been made in view of such a problem, and one of the exemplary purposes of an aspect thereof is to provide a method and a circuit capable of accurately estimating a deterioration state of a battery.

  One embodiment of the present invention relates to a method for estimating a deterioration state of a rechargeable battery. The estimation method includes a step of generating a coulomb count value by integrating the charge / discharge current of the battery, a step of monitoring the state of the battery, and that the battery has been charged / discharged by a predetermined amount of charge based on the coulomb count value. And every time charging / discharging of a predetermined amount of charge is detected, an index X indicating the deterioration of the battery is changed to an amount of change (in accordance with the state of the battery measured during the period of charging / discharging the predetermined amount of charge). Unit deterioration amount) ΔX, and a step of changing.

  According to this aspect, the progress of cycle deterioration can be adjusted according to the state of the battery in use, and the accuracy of estimation of the deterioration state can be improved. In this specification, “the battery has been charged and discharged with a predetermined amount of charge” means (i) the battery has been charged with a predetermined amount of charge, (ii) the battery has been discharged with a predetermined amount of charge, (iii This includes that the battery has been charged and discharged with a predetermined amount of charge, and (iv) the battery has been charged or discharged with a predetermined amount of charge.

  The state of the battery may include the temperature of the battery. Considering the temperature, it is possible to improve the accuracy of the deterioration estimation. The change amount ΔX may correspond to any of an average temperature, a maximum temperature, and a minimum temperature over a period during which the predetermined charge amount is charged and discharged. Considering any one of the average temperature, the maximum temperature, and the minimum temperature, the accuracy can be improved while suppressing an increase in calculation load.

The change amount ΔX is expressed by the formula (1) at least in the range of T> Tr.
ΔX = K × M ^{(T−Tr) / ΔT} (1)
However, K, M, Tr, and ΔT may be defined based on parameters. 20 ° C. ≦ Tr ≦ 30 ° C., 1 <M <3, 5 ° ≦ ΔT ≦ 20 °. The change amount ΔX may be defined based on Arrhenius' law (also referred to as 10 ° double speed or temperature double speed). In the range of T <Tr, ΔX = K may be satisfied. That is, it does not have to depend on temperature. Alternatively, ΔX may be according to equation (1) or according to another equation.

  In an aspect, the state of the battery may include an SOC (State Of Charge) of the battery. The change amount ΔX may depend on the SOC. By considering the SOC, it is possible to improve the estimation accuracy of the deterioration state. The parameter K may depend on the SOC.

  In an aspect, the estimation method may further include a step of measuring a time t required for charging / discharging the predetermined charge amount. The change amount ΔX may depend on the time t. According to this aspect, storage deterioration can be reflected. In some embodiments, the parameter K may depend on time t.

  The charging / discharging of the predetermined charge amount may correspond to one charging / discharging cycle. The index X may represent the number of charge / discharge cycles. The index X may represent a battery capacity.

  Another aspect of the present invention relates to a deterioration estimation circuit for a rechargeable battery. The battery monitoring circuit includes a cycle detection unit that detects that the battery has been charged and discharged based on a coulomb count value obtained by integrating the charging / discharging current of the battery, and a temperature for monitoring the temperature of the battery. Each time charging / discharging of a predetermined charge amount is detected by the monitoring circuit, the index X indicating the deterioration of the battery is changed by a change amount ΔX corresponding to the temperature T measured during the period when the predetermined charge amount is charged / discharged. A deterioration calculating unit.

Another embodiment of the present invention also relates to a deterioration estimation circuit for a rechargeable battery. The deterioration estimation circuit includes a correction coulomb counter circuit that generates a correction coulomb count value, a cycle detection unit that detects that the battery is charged and discharged based on the correction coulomb count value, a battery that has a predetermined charge amount, A deterioration calculation unit that changes a predetermined amount of an index X indicating battery deterioration each time the battery is charged or discharged. The correction coulomb counter circuit corrects the amount of change in the correction coulomb count value according to at least one of the temperature T, the SOC, and the cycle time _tCYC .

  Another embodiment of the present invention is an electronic device. The electronic device includes a rechargeable battery and the above-described deterioration estimation circuit that detects the state of the battery.

  Another embodiment of the present invention is an automobile. The automobile includes a rechargeable battery and the above-described deterioration estimation circuit that detects the state of the battery.

  Note that any combination of the above-described constituent elements and the constituent elements and expressions of the present invention replaced with each other among methods, apparatuses, systems, and the like are also effective as an aspect of the present invention.

  According to the present invention, it is possible to improve the estimation accuracy of the deterioration state of the battery.

It is a block diagram of a battery drive type electronic device. It is a figure which shows the relationship between the number of charging / discharging cycles and the deterioration degree of a battery. It is a block diagram of a battery management system provided with the deterioration estimation circuit which concerns on 1st Embodiment. It is a figure explaining a charging / discharging cycle. It is a block diagram which shows the structural example of a deterioration calculation part. FIG. 4 is an operation waveform diagram of the battery management system of FIG. 3. It is a block diagram of a battery management system provided with the degradation estimation circuit which concerns on 2nd Embodiment. It is a block diagram which shows the structural example of the deterioration calculation part of FIG. It is an operation | movement waveform diagram of the battery management system of FIG. It is a block diagram of a battery management system provided with the degradation estimation circuit which concerns on 3rd Embodiment. It is a block diagram which shows the structural example of the deterioration calculation part of FIG. It is an operation | movement waveform diagram of the battery management system of FIG. It is a block diagram of a battery management system provided with the residual amount detection circuit which concerns on 7th Embodiment. It is a block diagram of the correction | amendment coulomb counter circuit of FIG. It is a block diagram of the battery management system which concerns on 8th Embodiment. It is an operation | movement waveform diagram of the battery management system 100d which concerns on 8th Embodiment. It is a figure which shows the relationship between the battery voltage _VBAT and SOC in 8th Embodiment. It is an operation | movement waveform diagram of the battery management system of 9th Embodiment. It is a figure which shows the relationship between battery voltage _VBAT and SOC in 9th Embodiment. It is a figure which shows the relationship between battery voltage _VBAT and SOC in 10th Embodiment. It is a figure which shows the motor vehicle provided with a battery management system. It is a figure which shows an electronic device provided with a battery management system.

  The present invention will be described below based on preferred embodiments with reference to the drawings. The same or equivalent components, members, and processes shown in the drawings are denoted by the same reference numerals, and repeated descriptions are omitted as appropriate. The embodiments do not limit the invention but are exemplifications, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

In this specification, “the state in which the member A is connected to the member B” means that the member A and the member B are physically directly connected, or the member A and the member B are electrically connected to each other. Including the case of being indirectly connected through other members that do not substantially affect the state of connection, or do not impair the functions and effects achieved by the combination thereof.
Similarly, “the state in which the member C is provided between the member A and the member B” refers to the case where the member A and the member C or the member B and the member C are directly connected, as well as their electric It includes cases where the connection is indirectly made through other members that do not substantially affect the general connection state, or that do not impair the functions and effects achieved by their combination.

  Further, in this specification, a reference numeral attached to a voltage signal, a current signal, or a resistor represents a voltage value, a current value, or a resistance value as necessary.

(First embodiment)
FIG. 3 is a block diagram of the battery management system 100 including the deterioration estimation circuit 500 according to the first embodiment. The battery management system 100 includes a battery 102, a charging circuit 104, a load 108, and a remaining amount detection circuit (fuel gauge IC) 200. The battery 102 includes one or a plurality of cells. The type of the cell is not particularly limited, and examples include a lithium ion cell, a lithium air cell, a lithium metal base cell, a nickel hydrogen cell, a nickel cadmium cell, and a nickel zinc cell. The number of cells depends on the use of the battery management system 100, but in the case of a portable electronic device, it is on the order of one cell to several cells, and in the case of an in-vehicle battery, industrial device, or industrial machine, several tens to several hundred cells. . The configuration of the battery 102 is not particularly limited as an application of the present invention.

A battery voltage V _BAT from the battery 102 is supplied to the load 108. The type of the load 108 is not particularly limited. For example, if the battery management system 100 is mounted on an electronic device, the load 108 boosts or steps down the battery voltage V _BAT, and a power supply circuit for generating a supply voltage V _DD, various electronic operating by receiving power supply voltage V _DD A circuit may be included. When the battery management system 100 is mounted on an automobile or industrial machine, the load 108 can include a motor and an inverter that drives the motor by converting the battery voltage V _BAT into alternating current.

The charging circuit 104 receives the power supply voltage _VEXT from an external power adapter, a USB (Universal Serial Bus), a charging station, or the like, and charges the battery 102.

  The remaining amount detection circuit 200 detects a state of charge (SOC) of the battery 102. In this specification, for ease of understanding, the SOC is described as a percentage (%) where the minimum value is 0 and the maximum value is 100, but the present invention is not limited to this. For example, when the SOC is represented by 10 bits, it should be noted that the SOC is represented by 1024 gradations from 0 to 1023 in the process of digital signal processing.

The remaining amount detection circuit 200 mainly includes a coulomb counter circuit 202 and an SOC calculation unit 206. The coulomb counter circuit 202 generates a cumulative coulomb count value (hereinafter referred to as an ACC value) by integrating the charge / discharge current (I _BAT ) of the battery 102. The ACC value is expressed by the following equation.
ACC = ∫I _BAT dt
Coulomb counter circuit 202 samples battery current _IBAT at a predetermined sampling period Δt. The ACC value is calculated by the following formula using the battery current I _BAT [j] at each sampling time j.
ACC = Σ _{j = 1} (Δt × I _BAT [j])
This integration (integration) is performed, for example, with the current I _BAT flowing out from the battery 102 being positive and the current I _BAT flowing into the battery 902 being negative.

The method for detecting the current I _BAT is not particularly limited. For example, a sense resistor R _S may be inserted in series with the battery 102 on the path of the current I _BAT to detect a voltage drop of the sense resistor R _S. The sense resistor _RS may be inserted on the positive electrode side of the battery 102 or may be inserted on the negative electrode side. The coulomb counter circuit 202 includes an A / D converter that samples a voltage drop V _CS (or a voltage obtained by amplifying the voltage drop V _CS ) of the sense resistor _RS , and an integrator that accumulates output data of the A / D converter. May be included.

The SOC calculation unit 206 receives the ACC value from the coulomb counter circuit 202. The SOC calculation unit 206 calculates SOC (%) based on the following equation.
SOC = (CC _FULL− ACC) / CC _FULL × 100
However, CC _FULL is the coulomb count capacity value equivalent to full charge

  The battery management system 100 further includes a deterioration estimation circuit 500. Although the deterioration estimation circuit 500 is described as a part of the remaining amount detection circuit 200 in the present embodiment, the remaining amount detection circuit 200 and the deterioration estimation circuit 500 may be separate hardware, or a part of the hardware. May be shared.

The degradation estimation circuit 500 includes a cycle detection unit 502, a temperature detection circuit 504, and a degradation calculation unit 506. The cycle detection unit 502 detects that the battery 102 has been charged / discharged by a predetermined amount of charge based on the coulomb count value generated by the coulomb counter circuit 202. In some embodiments described below, the predetermined charge amount is a charge amount corresponding to the capacitance value CC _FULL . In some embodiments below, “predetermined charge amount is charged / discharged” corresponds to (iv) the battery has been charged and discharged with a predetermined charge amount. This is referred to as “charge / discharge cycle”.

The charge / discharge cycle will be described in detail. In one charge / discharge cycle, the integrated value of the discharge current (that is, the positive battery current I _BAT ) and the integrated value of the charge current (that is, the negative battery current I _BAT ) are each once, and the coulomb count capacity value of the battery 102 This is equivalent to reaching CC _FULL . The discharge coulomb count value is expressed as a DCC (Discharge Coulomb Count) value, and the charge coulomb count value is expressed as a CCC (Charge Coulomb Count) value.

The change amount of the DCC value reaches CC _FULL is called a discharge cycle, and the change amount of the CCC value reaches CC _FULL is called a charge cycle. CC _FULL can use the rated value CC _{FULL_RATED} , but it is _preferable to use a value CC _{FULL_AGED in} consideration of deterioration. When one discharge cycle occurs, the number of discharge cycles increases by one. Similarly, when one charge cycle occurs, the number of charge cycles increases by one. The number of charge / discharge cycles is increased by 1 when one charge / discharge cycle occurs, in other words, the number of discharge cycles and the number of charge cycles are each increased by 1. When the charge / discharge cycle, the charge cycle, and the discharge cycle are defined in this way, the number of charge / discharge cycles matches the smaller of the number of charge cycles and the number of discharge cycles.

  The coulomb counter circuit 202 generates a DCC value and a CCC value in addition to the ACC value. The cycle detection unit 502 detects a charge / discharge cycle based on the DCC value and the CCC value. The detection of the charge / discharge cycle is notified to the deterioration calculation unit 506. For example, each time the cycle detection unit 502 detects one charge / discharge cycle (that is, every time the number of charge / discharge cycles increases by 1), the cycle detection unit 502 asserts the output signal (detection signal) S1 (for example, high level), The deterioration calculation unit 506 may be notified. Alternatively, the deterioration calculation unit 506 may monitor a register that stores the number of charge / discharge cycles, and the change in the value of the register may be notified of detection of the charge / discharge cycle.

FIG. 4 is a diagram illustrating a charge / discharge cycle. Here, the DCC value and the CCC value are assumed to be reset to zero when they reach CC _FULL , but are not necessarily reset. The discharge cycle is shown as CYC _D , the charge cycle as CYC _D , and the charge / discharge cycle as CYC _CD .

  Returning to FIG. The temperature detection circuit (state monitoring circuit) 504 monitors the temperature T of the battery 102 as one of the states of the battery 102 and generates temperature information S2 indicating the temperature T. For example, the temperature detection circuit 504 may include a temperature sensor such as a thermocouple or a thermistor attached to or near the battery 102 and an A / D converter that converts the output of the temperature sensor into a digital value.

The deterioration calculation unit 506 generates an index X indicating the deterioration of the battery 102. Degradation calculator 506 (each time it is detected that is charge-discharge cycle CYC _CD) charge and discharge a predetermined amount of charge of the battery 102 each time it is detected, the index X, a predetermined amount of charge in the charge and discharge time period The amount of change ΔX corresponding to the measured temperature T is changed. When the current index is X [i], the temperature measured in the i th charge / discharge cycle CYC _CDi is T [i], and the corresponding change is ΔX [i], the i th charge / discharge cycle CYC _CD A new index X [i + 1] after detection of is expressed by the following equation.
X [i + 1] = X [i] + ΔX [i]
ΔX [i] = f (T [i])
Here, f () is a function indicating the relationship between the change amount ΔX and the temperature T.

For example, the change amount ΔX [i] may correspond to the average temperature Tave [i] over a period during which a predetermined charge amount is charged / discharged (that is, a charge / discharge cycle).
ΔX [i] = f (Tave [i])

  When ΔX = 1 is fixed, the index X corresponds to the number of charge / discharge cycles. Therefore, the index X generated by the deterioration calculation unit 506 can be grasped as the number of charge / discharge cycles corrected according to the use condition such as temperature. The index X is also referred to as the number of deterioration cycles.

The speed of the chemical reaction is empirically known to be Arrhenius' law (also referred to as 10 degrees double speed or temperature double speed) when the temperature increases by 10 °. The inventor has uniquely recognized that Arrhenius' law is applicable to battery degradation and is suitable for modeling the temperature dependence of battery cycle degradation. In the present embodiment, the change amount ΔX is defined based on the equation (1) with respect to the average temperature Tave.
ΔX = K × M ^{(Tave−Tr) / ΔT} (1)
Where K, M, Tr and ΔT are parameters

  Tr is a reference temperature (for example, room temperature), and may be 20 ° C. ≦ Tr ≦ 30 ° C. Hereinafter, Tr = 25 ° C. Further, 1 <M <3 may be satisfied. Since the power of 2 is easy to implement in hardware, M = 2 may be used. Alternatively, 5 ° ≦ ΔT ≦ 20 ° may be set. Hereinafter, ΔT = 10 °. In this embodiment, K = 1.

  K, M, Tr, and ΔT may be set to optimum values so as to best fit the actual battery deterioration curve according to the vendor, type, lot, and individual of the battery 102. It is preferable that at least one of K, M, Tr, and ΔT can be set from the outside of the remaining amount detection circuit 200. Therefore, the remaining amount detection circuit 200 has at least one set value of K, M, Tr, and ΔT. And an interface circuit that receives a set value from the outside and writes it to the register.

The change amount ΔX changes according to the formula (1) at least in the range of Tave> Tr. In the present embodiment, the change amount ΔX does not depend on the temperature in the range of Tave <Tr.
(1) Tave> Tr
ΔX = K × M ^{(Tave−Tr) / ΔT}
(2) Tave <Tr
ΔX = K

Further, the deterioration calculation unit 506 estimates the capacity of the deteriorated battery according to a predetermined relational expression based on the index X. More specifically, the capacity CC _{FULL_AGED} of the deteriorated battery is estimated according to the equation (2) when the rated battery capacity is CC _{FULL_RATED} .
CC _{FULL_AGED} = CC _{FULL_RATED−} X × α (2)
However, (alpha) represents a degradation coefficient and the unit is coulomb.
That is, the battery capacity (coulomb count capacity value) CC _{FULL_AGED} is decreased according to the equation (2) based on the index (number of deterioration cycles) X. The degradation coefficient α may be a constant, but may be a variable as described in the eighth to tenth embodiments described later. The SOC calculation unit 206 can calculate the SOC (%) based on the battery capacity (referred to as a deteriorated battery capacity) CC _{FULL_AGED} in consideration of deterioration.
SOC = (CC _{FULL_AGED−} ACC) / CC _{FULL_AGED} × 100

  FIG. 5 is a block diagram illustrating a configuration example of the deterioration calculation unit 506. The deterioration calculation unit 506 includes an average temperature detection unit 510, a change amount calculation unit 512, and an index calculation unit 514. The average temperature detection unit 510 detects the average temperature Tave [i] of the current (i-th) charge / discharge cycle based on the temperature information S2 from the temperature detection circuit 504. The change amount calculation unit 512 calculates the change amount ΔX based on the equation (1). Note that the calculation in this specification includes other means such as table reference in addition to calculation processing by software or hardware. The index calculation unit 514 holds the current deterioration cycle number X [i] in the register 516 and adds a change amount ΔX [i] to generate a new deterioration cycle number X [i + 1]. The value is stored in the register 516. Note that the deterioration calculation unit 506 may be configured by hardware, a processor that executes software, or a combination thereof.

The above is the configuration of the battery management system 100 according to the first embodiment. Next, the operation will be described. FIG. 6 is an operation waveform diagram of the battery management system 100 of FIG. FIG. 6 shows SOC, charge / discharge cycle number CYC _CD , temperature T, and index (deterioration cycle number) X in order from the top. Here, for ease of understanding, the number of charge / discharge cycles CYC _CD starts from 1. At time t1, the first cycle is completed. The average value of the temperatures T at times t0 to t1 is Tave ₁ . For example, when Tr = 25 ° C., Tave ₁ = 45 ° C., ΔT = 10 °, and K = 1, the change amount ΔX [1] is
ΔX [1] = 1 × 2 ^{(45−25) / 10} = 4
And the deterioration cycle number X [2] is X [2] = X [1] + 4 = X _INIT +4
It becomes. That is, in the first charge / discharge cycle, the battery 102 is estimated to have deteriorated for four cycles.

At time t2, the second cycle is completed. The average value of the temperatures T at times t1 to t2 is Tave ₂ . For example, when Tave ₂ = 35 ° C., the change amount ΔX [2] is
ΔX [2] = 1 × 2 ^{(35−25) / 10} = 2
And the number of degradation cycles X [3] is X [3] = X [2] + 2 = X _INIT +6
It becomes. That is, in the second charge / discharge cycle, the battery 102 is estimated to have deteriorated for two cycles.

At time t3, the third cycle is completed. The average value of the temperatures T at times t2 to t3 is Tave ₃ . For example, when Tave ₃ = 20 ° C., since T _ave3 <Tr, the change amount ΔX [2] is
ΔX [2] = 1
And the number of degradation cycles X [4] is X [4] = X [3] + 1 = X _INIT +7
It becomes. That is, in the third charge / discharge cycle, the battery 102 is estimated to have deteriorated for one cycle.

  The above is the operation of the battery management system 100 of FIG. According to the battery management system 100, the progress of cycle deterioration (that is, the change amount ΔX) can be adjusted according to the temperature T when the battery 102 is used, and the accuracy of estimation of the deterioration state can be improved. In particular, by considering the average time Tave, the accuracy can be improved while suppressing an increase in the calculation load.

(Second Embodiment)
FIG. 7 is a block diagram of a battery management system 100a including a deterioration estimation circuit 500a according to the second embodiment. In the deterioration estimation circuit 500a, the SOC generated by the SOC calculation unit 206 is input to the deterioration calculation unit 506a. The SOC of the battery is reflected in the amount of change ΔX in the number of deterioration cycles X. In general, it has been found that in a region where the SOC is large, the deterioration proceeds faster than in a region where the SOC is small. Therefore, by adjusting the change amount ΔX according to the SOC, it is possible to further improve the estimation accuracy of the deterioration state.

When ΔX is described by equation (1), SOC may be reflected in the parameter K. For example, the SOC of the battery 102 is divided into a plurality of ranges. Here, for ease of understanding and simplification of explanation, two ranges, that is, an upper range (that is, 50 to 100%) higher than a predetermined threshold SOC _TH (here, 50%), a threshold SOC. It shall be divided into lower ranges (0 to 50%) lower than _TH . The value of threshold value SOC _TH and the number of ranges are not particularly limited. The parameter K in the equation (1) has a different value for each SOC range.
That is,
K = β _{1 for} 50% ≦ SOC ≦ 100%
K = β ₂ for 0% ≦ SOC <50%
Note that β ₁ and β ₂ may be determined so as to satisfy β ₁ + β ₂ = 1.

In summary, the change amount ΔX may be generated as follows.
(1) Tave> Tr
ΔX = β ₁ × M ^{(Tave−Tr) / ΔT} for 50% ≦ SOC ≦ 100%
ΔX = β ₂ × M ^{(Tave−Tr) / ΔT} for 0% ≦ SOC <50%
(2) Tave <Tr
ΔX = β ₁ for 50% ≦ SOC ≦ 100%
ΔX = β ₂ for 0% ≦ SOC <50%

  For example, the deterioration calculation unit 506 detects the average temperature Tave for each SOC range. The average temperature in the upper range 50% ≦ SOC ≦ 100% is TaveH, and the average temperature in the lower range 0% ≦ SOC <50% is TaveL.

When the SOC changes within one range (for example, only the upper range) within one charge / discharge cycle, the amount of change ΔX may be calculated as follows based on the average temperature TaveH.
ΔX = ΔX _H = β ₁ × M ^{(TaveH−Tr) / ΔT} for Tave> Tr
ΔX = ΔX _H = β ₁ for Tave <Tr

Similarly, when the SOC changes within another range (for example, only the lower range) within one charge / discharge cycle, the amount of change ΔX may be calculated as follows based on the average temperature TaveL.
ΔX = ΔX _L = β ₂ × M ^{(TaveL−Tr) / ΔT} for Tave> Tr
ΔX = ΔX _L = β ₂ for Tave <Tr

If, within one charge-discharge cycle, when the SOC varies across a plurality of ranges, the change amount [Delta] X is the amount of change is calculated for each of a plurality of ranges [Delta] X _H, may be the average value of [Delta] X _L.
ΔX = (ΔX _H + ΔX _L ) / 2 (3)
In this case, the deterioration cycle number X is represented by the formula (4).
X [i + 1] = X [i] + ΔX
= X [i] + (ΔX _H + ΔX _L ) / 2 (4)

Alternatively, the deterioration cycles X _H and _XL may be calculated individually for each SOC range, and the average thereof may be used as the deterioration cycle number X of one charge / discharge cycle.
X _H [i + 1] = X [i] + ΔX _H [i]
X _L [i + 1] = X [i] + ΔX _L [i]
X [i + 1] = ( _XH [i + 1] + _XL [i + 1]) / 2
== X [i] + (ΔX _H + ΔX _L ) / 2 (5)
Note that equation (5) matches equation (4).

FIG. 8 is a block diagram illustrating a configuration example of the deterioration calculation unit 506a in FIG. Range determination unit 524 determines which of the plurality of ranges the current SOC is included in. During the period included in the upper range, the first average temperature detection unit 520 is enabled, and the average temperature TaveH is updated. On the contrary, during the period included in the lower range, the second average temperature detection unit 522 is enabled, and the average temperature TaveL is updated. The first change amount calculation unit 526 calculates the change amount [Delta] X _H in the upper range, based on the average temperature TaveH, second change amount calculation unit 528 calculates the change amount [Delta] X _L in the lower range based on the average temperature TaveL . Index calculation unit 530, the change amount [Delta] X _H, calculates the number of cycles to deterioration based on _{ΔX L X [i + 1]} .

The above is the configuration of the battery management system 100a according to the second embodiment. Next, the operation will be described. FIG. 9 is an operation waveform diagram of the battery management system 100a of FIG. At time t1, the first cycle is completed. At time t0 to t1, since SOC> 50%, it is determined as the upper range, and therefore, the average value of the temperature T is calculated as TaveH. Since TaveH> Tr, the change amount ΔX [1] is as follows.
ΔX [1] = β ₁ × M ^{(TaveH−Tr) / ΔT}

At time t3, the second cycle is completed. Among the times t1 to t3, in the first half t1 to t2, since SOC> 50%, it is determined as the upper range, and the average temperature TaveH is calculated. In the latter half t2 to t3, since SOC <50%, the lower range is determined, and the average temperature TaveL is calculated.
Since TaveH> Tr,
ΔX _H [2] = β ₁ × M ^{(TaveH−Tr) / ΔT}
Since TaveL <Tr,
ΔX _L [2] = β ₂
It becomes. Therefore, the change amount ΔX [2] in the second cycle is (ΔX _H [2] + ΔX _L [2]) / 2. The above is the operation of the battery management system 100a of FIG.

  According to the second embodiment, by reflecting the SOC in addition to the temperature T in the change amount ΔX of the number of deterioration cycles X, the estimation accuracy of the deterioration state is further improved than in the first embodiment. it can.

(Third embodiment)
FIG. 10 is a block diagram of a battery management system 100b including a deterioration estimation circuit 500b according to the third embodiment. The degradation estimation circuit 500b further includes a cycle time measurement unit 508 that measures a cycle time t _CYC required for each charge / discharge cycle. The change amount ΔX depends on the length of the cycle time t _CYC .

For example, the cycle time t _CYC is _divided into a plurality of ranges. Here, in order to facilitate understanding and simplify the description, two ranges, that is, a first range longer than a predetermined threshold value t _TH (t _CYC > t _TH ) and a second range shorter than the threshold value t _TH ( It is assumed that t _CYC <t _TH ), but the value of the threshold value t _TH and the number of ranges are not particularly limited. The parameter K in equation (1) has a different value for each range of the cycle time t _CYC .
K = γ ₁ for t _TH <t _CYC
K = γ ₂ for t _CYC <t _TH
For example, t _TH is preferably set to a value such that the first range can be regarded as a so-called storage deterioration region.

In summary, the change amount ΔX may be generated as follows.
(1) Tave> Tr
ΔX = γ ₁ × M ^{(Tave−Tr) / ΔT} for t _TH <t _CYC
ΔX = γ ₂ × M ^{(Tave−Tr) / ΔT} for t _CYC <t _TH
(2) Tave <Tr
ΔX = γ ₁ for t _TH <t _CYC
ΔX = γ ₂ for t _CYC <t _TH

FIG. 11 is a block diagram illustrating a configuration example of the deterioration calculation unit 506b of FIG. The average temperature detection unit 540 acquires the average temperature Tave. The range determination unit 542 determines in which of the plurality of ranges the cycle time t _CYC is included. The change amount calculation unit 544 selects a parameter (γ ₁ , γ ₂ ) corresponding to the length of the cycle time t _CYC and calculates a change amount ΔX corresponding to the average temperature Tave. The index calculation unit 546 changes the deterioration cycle number X by the change amount ΔX.

The above is the configuration of the battery management system 100b according to the third embodiment. Next, the operation will be described. FIG. 12 is an operation waveform diagram of the battery management system 100b of FIG. At the times t1, t2, t3, and t4, the first, second, third, and fourth cycle counts are completed. Cycle time _{t CYC1, t CYC3, t CYC4} is shorter than the threshold _{t TH,} cycle time _{t CYC2} is longer than the threshold _{t TH.} The average temperatures Tave ₁ and Tave ₄ are higher than the threshold value Tr, and the average temperatures Tave ₂ and Tave ₃ are lower than the threshold value Tr.

Changes ΔX [1] to X [4] in each cycle are as follows.
ΔX [1] = γ ₂ × M ^{(Tave1-Tr) / ΔT}
ΔX [2] = γ ₁
ΔX [3] = γ ₂
ΔX [4] = γ ₂ × M ^{(Tave4-Tr) / ΔT}

The above is the operation of the battery management system 100b of FIG. According to the battery management system 100b, t _CYC <t _TH, that is, it is estimated that the deterioration due to normal use is different from the case where t _CYC > t _TH, that is, it is estimated that the deterioration is storage deterioration. By using the value parameter K, the storage deterioration can be reflected in the deterioration cycle number X.

(Fourth embodiment)
The fourth embodiment is a combination of the second embodiment and the third embodiment. That is, the SOC and the cycle time t _CYC are reflected in the index (number of deterioration cycles) X.
In this case, the change amount ΔX may be calculated as follows.
(1) TaveH, TaveL> Tr
(1a) t> t _CYC
ΔX _H = γ ₁ × β ₁ × M ^{(TaveH-Tr) / ΔT}
ΔX _L = γ ₁ × β ₂ × M ^{(TaveL-Tr) / ΔT}
ΔX = (ΔX _H + ΔX _L ) / 2
(1b) t <t _CYC
ΔX _H = γ ₂ × β ₁ × M ^{(TaveH-Tr) / ΔT}
ΔX _L = γ ₂ × β ₂ × M ^{(TaveL-Tr) / ΔT}
ΔX = (ΔX _H + ΔX _L ) / 2
(2) TaveH, TaveL <Tr
(2a) t> t _CYC
ΔX _H = γ ₁ × β ₁
ΔX _L = γ ₁ × β ₂
ΔX = (ΔX _H + ΔX _L ) / 2
(2b) t <t _CYC
ΔX _H = γ ₂ × β ₁
ΔX _L = γ ₂ × β ₂
ΔX = (ΔX _H + ΔX _L ) / 2

(3) TaveH> Tr, TaveL <Tr
(3a) t> t _CYC
ΔX _H = γ ₁ × β ₁ × M ^{(TaveH-Tr) / ΔT}
ΔX _L = γ ₁ × β ₂
ΔX = (ΔX _H + ΔX _L ) / 2
(3b) t <t _CYC
ΔX _H = γ ₂ × β ₁ × M ^{(TaveH-Tr) / ΔT}
ΔX _L = γ ₂ × β ₂
ΔX = (ΔX _H + ΔX _L ) / 2

(4) TaveH <Tr, TaveL> Tr
(4a) t> t _CYC
ΔX _H = γ ₁ × β ₁
ΔX _L = γ ₁ × β ₂ × M ^{(TaveL-Tr) / ΔT}
ΔX = (ΔX _H + ΔX _L ) / 2
(4b) t <t _CYC
ΔX _H = γ ₂ × β ₁
ΔX _L = γ ₂ × β ₂ × M ^{(TaveL-Tr) / ΔT}
ΔX = (ΔX _H + ΔX _L ) / 2

(Fifth embodiment)
In the fifth embodiment, the temperature T is not reflected in the change amount ΔX, and the SOC and the cycle time t _CYC are considered. Therefore, the degradation estimation circuit 500c (not shown) according to the fifth embodiment can be understood as a configuration in which the temperature detection circuit 504 is omitted from the block diagram of FIG. In the fifth embodiment, the change amount ΔX can be determined as follows.
ΔX [i] = g (SOC [i], t _CYC [i])
Here, g () is a function indicating the relationship between the change amount ΔX and the SOC and _tCYC .

For example, ΔX [i] may be defined as follows.
(1) t> t _CYC
ΔX _H = γ ₁ × β ₁
ΔX _L = γ ₁ × β ₂
ΔX = (ΔX _H + ΔX _L ) / 2
(2) t <t _CYC
ΔX _H = γ ₂ × β ₁
ΔX _L = γ ₂ × β ₂
ΔX = (ΔX _H + ΔX _L ) / 2

(Sixth embodiment)
Alternatively, only the SOC may be reflected in the change amount ΔX.
ΔX [i] = h1 (SOC [i])
However, h1 () is a function indicating the relationship between the change amount ΔX and the SOC.

Alternatively, only the cycle time t _CYC may be reflected in the change amount ΔX.
ΔX [i] = h2 (t _CYC [i])
However, h2 () is a function indicating the relationship between the change amount ΔX and the cycle time _tCYC .

(Seventh embodiment)
FIG. 13 is a block diagram of a battery management system 100c including a remaining amount detection circuit 200c according to the seventh embodiment. The remaining amount detection circuit 200c includes a coulomb counter circuit 202, an SOC calculation unit 206, and a deterioration estimation circuit 600.

The degradation estimation circuit 600 mainly includes a correction coulomb counter circuit 602, a cycle detection unit 604, and a degradation calculation unit 606. The corrected coulomb counter circuit 602 generates corrected coulomb count values DCC ′ and CCC ′. The cycle detection unit 604 detects that the battery 102 has been charged / discharged by a predetermined amount of charge (that is, a charge / discharge cycle) based on the corrected coulomb count values DCC ′ and CCC ′. The deterioration calculation unit 606 changes the index X indicating the deterioration of the battery 102 by a predetermined amount each time the battery 102 is charged / discharged by a predetermined charge amount. For example, when the index X is the number of deterioration cycles, the number of deterioration cycles is incremented by 1 each time a charge / discharge cycle is detected. Further, the capacity of the battery, that is, the value of CC _FULL of the SOC calculation unit 206 is updated according to the number of deterioration cycles X.

The correction coulomb counter circuit 602 corrects the change amount of the correction coulomb count values DCC ′ and CCC ′ according to at least one of the temperature T, the SOC, and the cycle time _tCYC . The temperature detection circuit 608 and the cycle time measurement unit 610 are provided as necessary.

In the case of a general coulomb counter (202), when the charge / discharge charge amount for a certain sampling j is I _BAT [j],
CC [j + 1] = CC [j] + Δt × I _BAT [j]
It is represented by Normalizing to Δt = 1 for simplicity of explanation,
CC [j + 1] = CC [j] + I _BAT [j]
It becomes.

On the other hand, in the correction coulomb counter circuit 602,
CC ′ [j + 1] = ε [j] × CC ′ [j] + I _BAT [j]
The corrected coulomb count value CC ′ is calculated by Here, ε is a correction coefficient corresponding to at least one of temperature T, SOC, and cycle time t _CYC . The above Δt may be interpreted as included in ε. This correction coefficient ε corresponds to the change amount ΔX described in the first to fourth embodiments.

1. When the temperature dependency correction coefficient ε is a function of the temperature T, the analogy with the first embodiment may be considered, and ΔX may be read as ε. Therefore, ε can be expressed by the formula (1a) in the range of T> Tr.
ε = K × M ^{(T−Tr) / ΔT} (1a)
In the present embodiment, the temperature T can be reflected on a time scale shorter than the cycle of the charge / discharge cycle, that is, on the time scale of the count cycle of the coulomb counter.

2. SOC Dependence Further, when SOC is reflected, an analogy with the second embodiment may be considered. In the present embodiment, it is not necessary to calculate the average temperature Tave for each SOC range. For example, the correction coefficient ε may be calculated as follows.
(1) T> Tr
(1a) SOC> SOC _TH
ε = β ₁ × M ^{(T−Tr) / ΔT}
(1b) SOC <SOC _TH
ε = β ₂ × M ^{(T-Tr) / ΔT}

(2) T <Tr
(2a) SOC> SOC _TH
ε = β ₁
(2b) SOC <SOC _TH
ε = β ₂

3. Cycle time dependency When reflecting the cycle time t _CYC , the analogy with the third embodiment may be considered.
(1) T> Tr
(1a) t _CYC > t _TH , SOC> SOC _TH
ε = γ ₁ × β ₁ × M ^{(T-Tr) / ΔT}
(1b) t _CYC > t _TH , SOC <SOC _TH
ε = γ ₁ × β ₂ × M ^{(T-Tr) / ΔT}
(1c) t _CYC <t _TH , SOC> SOC _TH
ε = γ ₂ × β ₁ × M ^{(T-Tr) / ΔT}
(1b) t _CYC <t _TH , SOC <SOC _TH
ε = γ ₂ × β ₂ × M ^{(T-Tr) / ΔT}

(2) T <Tr
(2a) t _CYC > t _TH , SOC> SOC _TH
ε = γ ₁ × β ₁
(2b) t _CYC > t _TH , SOC <SOC _TH
ε = γ ₁ × β ₂
(2c) t _CYC <t _TH , SOC> SOC _TH
ε = γ ₂ × β ₁
(2b) t _CYC <t _TH , SOC <SOC _TH
ε = γ ₂ × β ₂

FIG. 14 is a block diagram of the correction coulomb counter circuit 602 of FIG. FIG. 14 shows a configuration for calculating the ACC value. As described above, the sense resistor R _S is inserted on the path of the battery current (charge / discharge current) I _BAT , and a voltage drop V _CS proportional to the battery current I _BAT is generated in the sense resistor R _S. I _BAT is positive when charging and negative when discharging. The current detection circuit 620 includes an A / D converter, and converts the voltage drop V _S into a digital value I _BAT [j]. j represents the sampling time. The current detection circuit 620 may further include an amplifier that amplifies the voltage drop Vs.

The correction coefficient calculator 622 calculates a correction coefficient ε [j] corresponding to at least one of the temperatures T, SOC, and _tCYC . The multiplier 624 multiplies I _BAT [j] by ε [j] to generate ΔCC ′ [j]. This ΔCC ′ [j] corresponds to the amount of change in the coulomb count value.

  Register 626 holds the current DCC ′ [j]. When ΔCC ′ [j] is negative (that is, when discharging), adder 628 adds the value (or its absolute value) to DCC ′ [j] of register 626, and adds new DCC ′ [j + 1]. Generate. The value in register 626 is updated with the new DCC '[j + 1].

  Register 630 holds the current CCC ′ [j]. When ΔCC ′ [j] is positive (that is, during charging), the adder 632 adds the value to CCC ′ [j] in the register 630 to generate a new CCC ′ [j + 1]. The value of the register 630 is updated by the new CCC ′ [j + 1].

(Eighth embodiment)
FIG. 15 is a block diagram of a battery management system 100d according to the eighth embodiment. The remaining amount detection circuit 200d includes a coulomb counter circuit 202, an SOC calculation unit 206, and a deterioration estimation circuit 700. The functions and operations of the coulomb counter circuit 202 and the SOC calculation unit 206 have already been described.

  The degradation estimation circuit 700 mainly includes a cycle detection unit 702 and a degradation calculation unit 704. When detecting the charge / discharge cycle, the cycle detection unit 702 asserts the detection signal S1.

Degradation calculator 704, each time the detection signal S1 is asserted, 1 charge and discharge cycles _{CYC CD,} increments.

The deterioration calculation unit 704 receives the ACC value from the coulomb counter circuit 202, and calculates the deterioration of the battery capacity, that is, the battery capacity CC _{FULL_AGED} . In this embodiment, the deterioration coefficient α in equation (2) when calculating the deteriorated battery capacity CC _{FULL_AGED} may be treated as a variable and updated for each charge / discharge cycle.

The deterioration calculation unit 704 calculates a deterioration battery capacity CC _{FULL_AGED_EST1} for estimation. In the present embodiment, CC _{FULL_AGED_EST1} is the same as CC _{FULL_AGED in} Expression (2).
CC _{FULL_AGED_EST1} = CC _{FULL_RATED−} CYC _CD × α (2a)

In addition, the deterioration calculation unit 704 calculates a current remaining coulomb count value CCNOW that does not consider battery deterioration. CCNOW represents the remaining charge amount of the battery.
CCNOW = CC _{FULL_RATED-} ACC (7a)

Further, the deterioration calculation unit 704 calculates a current remaining coulomb count value CCNOW_EST1 in consideration of battery deterioration.
_{CCNOW_EST1 = CCNOW- (CC FULL_RATED -CC FULL_AGED_EST1} )
= CC _{FULL_AGED_EST1-} ACC (7b)

When the remaining coulomb count value CCNOW_EST1 in consideration of deterioration becomes zero, if the battery voltage V _BAT does not reach the voltage corresponding to the remaining zero (system minimum operating voltage) V _{BAT_MIN} , the current CCNOW The value is ERR_CC.

Degradation calculation unit 704 may calculate SOC_EST1 by the following equation (8), and the value of CCNOW when the value of SOC_EST1 becomes zero may be ERR_CC. Since SOC_EST1 is nothing but the SOC calculated in the SOC calculation unit 206, the deterioration calculation unit 704 may monitor the output of the SOC calculation unit 206.
SOC_EST1 = CCNOW_EST1 / CC _{FULL_AGED_EST1} × 100
= (CC _{FULL_AGED_EST1−} ACC) / CC _{FULL_AGED_EST1} × 100 (8)

The deterioration calculation unit 704 corrects the deterioration coefficient α using ERR_CC, and uses it as the deterioration coefficient α in Expression (2) in the subsequent cycles. For example, the corrected deterioration coefficient α ′ may be calculated according to the equation (9).
α ′ = (α + ERR_CC) / CYC _CD (9)

The correction formula is not limited to this, and ERR_CC may be defined so that α ′ is larger than α and monotonically increases with respect to ERR_CC. Generalizing with an arbitrary function f,
α ′ = f (ERR_CC, α) (10)
However, the function f is
When ERR_CC1> ERR_CC2,
f (ERR_CC1, α)> f (ERR_CC2, α)
Meet.

The above is the configuration of the remaining amount detection circuit 200d. Next, the operation will be described. FIG. 16 is an operation waveform diagram of the battery management system 100d of FIG. When the battery 102 is discharged by the load current _{I LOAD,} CCNOW value and CCNOW_EST1 value decreases with time. The initial value CC _{FULL_AGED_EST1} of _{CCNOW_EST1} is a value estimated based on the formula (2a) from the past number of charge / discharge cycles. CCNOW_TRUE indicates a correct charge amount.

Further, the battery voltage V _BAT decreases from the full charge voltage V _{BAT_FULL} with time. The battery voltage V _BAT becomes the minimum operating voltage V _{BAT_MIN at} time t1 when the correct charge amount CCNOW_TRUE becomes zero. When the initial value (battery capacity) CC _{FULL_AGED_EST1} is smaller than the correct value CC _{FULL_TRUE} , CCNOW_EST1 becomes zero at time t0 before time t1 when the battery becomes empty.

The deterioration calculation unit 704 acquires the value ERR_CC of CCNOW at time t0 and corrects the deterioration coefficient α. Then, the deteriorated battery capacity CC _{FULL_AGED} is calculated according to the equation (2a) using the corrected deterioration coefficient α. In addition, an estimated deteriorated battery capacity CC _{FULL_AGED_EST1} is calculated.

FIG. 17 is a diagram showing a relationship between battery voltage _VBAT and SOC. Note that V _BAT and SOC are actually non-linear, but here they are straight for simplicity of explanation. The solid line indicates the correct SOC_TRUE. If the estimated value CC _{FULL_AGED} of the deteriorated battery capacity is smaller than the true value CC _{FULL_TRUE} , as shown by the one-dot chain line, the battery voltage V _BAT reaches the minimum operating voltage V _{BAT_MIN} even though the charge remains. Even though it is not, SOC_EST1 becomes zero.

When this state is detected, the battery management system 100d in FIG. 15 corrects the deterioration coefficient α according to the equation (8) or another function f. As a result, the deteriorated battery capacity CC _{FULL_AGED} is corrected so as to increase, and the subsequent SOC_EST1 can be corrected so as to approach the correct SOC (SOC_TRUE) as shown by a broken line in FIG.

  The above is the operation of the remaining amount detection circuit 200d. By correcting the deterioration coefficient α, it is possible to improve the estimation accuracy of battery deterioration.

(Ninth embodiment)
In the eighth embodiment, when the deteriorated battery capacity CC _{FULL_AGED} is estimated to be smaller than the correct value, the value can be corrected. However, when the estimated value is larger than the correct value, the correction is performed. Can not do it. The ninth embodiment provides a technique effective even in such a case.

The block diagram of the battery management system according to the ninth embodiment is the same as that of FIG. 15, and the processing of the deterioration calculation unit 704 is different. The deterioration calculating unit 704 calculates the deteriorated battery capacity CC _{FULL_AGED_EST2} based on the equation (2b) instead of the equation (2a). This CC _{FULL_AGED_EST2} is not CC _{FULL_AGED} used in the SOC calculation unit 206 but is referred to for correcting the deterioration coefficient α.
CC _{FULL_AGED_EST2} = CC _{FULL_RATED−} CYC _CD × α × N (2b)
N is a constant where N> 1.

Further, the current remaining coulomb count value CCNOW_EST2 considering the battery deterioration is calculated based on the equation (7b).
_{CCNOW_EST2 = CCNOW- (CC FULL_RATED -CC FULL_AGED_EST2} )
= CC _{FULL_AGED_EST2-} ACC (7b)

Degradation calculation unit 704 calculates SOC_EST2 according to equation (8b) instead of equation (8). It should be noted that SOC_EST2 is different from the SOC calculated by the SOC calculation unit 206 in the ninth embodiment.
SOC_EST2 = CCNOW_EST2 / CC _{FULL_AGED_EST2} × 100
= (CC _{FULL_AGED_EST2−} ACC) / CC _{FULL_AGED_EST2} × 100 (8b)

  Deterioration calculating unit 704 sets CCNOW to ERR_CC when SOC_EST2 calculated by Expression (8b) becomes zero, that is, when CCNOW_EST2 is zero. The deterioration calculation unit 704 corrects the deterioration coefficient α using ERR_CC. For the correction, equation (9) or another function f can be used.

Next, the operation of the ninth embodiment will be described.
FIG. 18 is an operation waveform diagram of the battery management system according to the ninth embodiment. FIG. 19 is a diagram showing the relationship between battery voltage V _BAT and SOC. The solid line indicates the correct SOC.

When the deteriorated battery capacity CC _{FULL_AGED} is smaller than the correct value, the battery voltage V _BAT becomes the lowest operating voltage V _{BAT_MIN} at time t1 before time t2 when SOC_EST1 (or CCNOW_EST1) calculated in the eighth embodiment becomes zero. To fall.

  The SOC_EST2 calculated in the ninth embodiment is intentionally estimated to have a larger deterioration than the SOC_EST1. This SOC_EST2 becomes zero at time t0 before time t1, and the value of CCNOW at that time can be obtained as ERR_CC.

Thus, according to the ninth embodiment, even when the deteriorated battery capacity CC _{FULL_AGED} is estimated to be smaller than the correct value, the value can be brought close to the correct value.

(Tenth embodiment)
The tenth embodiment is a modification of the ninth embodiment.
The deterioration calculating unit 704 calculates the deteriorated battery capacity CC _{FULL_AGED_EST3} based on the equation (2c) instead of the equation (2b).
CC _{FULL_AGED_EST3} = CC _{FULL_RATED} × M-CYC _CD × α × N (2c)
N> 1,0 <M <1.

Degradation calculation unit 704 calculates CCNOW_EST3 and SOC_EST3 according to equations (7c) and (8c).
_{CCNOW_EST3 = CCNOW- (CC FULL_RATED -CC FULL_AGED_EST3} )
= CC _{FULL_AGED_EST3−} ACC (7c)

SOC_EST3 = CCNOW_EST3 / CC _{FULL_AGED_EST3} × 100
= (CC _{FULL_AGED_EST3−} ACC) / CC _{FULL_AGED_EST3} × 100 (8c)

  Deterioration calculation unit 704 sets CCNOW to ERR_CC when SOC_EST3 calculated by equation (8c) becomes zero, that is, when CCNOW_EST3 is zero. The deterioration calculation unit 704 corrects the deterioration coefficient α using ERR_CC. For the correction, equation (9) or another function f can be used.

Next, the operation of the tenth embodiment will be described.
When M = (100−Y) / 100, the expression (2c) corresponds to the fact that Y% of the battery capacity is regarded as 0%. FIG. 20 is a diagram showing the relationship between the battery voltage V _BAT and the SOC in the tenth embodiment. The solid line indicates the correct SOC. Z is the battery voltage V _BAT when the SOC becomes Y%. Z may be measured in advance. Alternatively, a difference ΔV between the OCV voltage and V _{BAT — MIN} when the SOC is 0% may be obtained from the SOC-OCV table, and may be subtracted from the open circuit voltage OCV [Y%] when the SOC is Y%.
Z = OCV [Y%]-ΔV

According to the tenth embodiment, the deteriorated battery capacity CC _{FULL_AGED} can be estimated more correctly.

  In the above, this invention was demonstrated based on some embodiment. Those skilled in the art will understand that these embodiments are exemplifications, and that various modifications can be made to combinations of the respective constituent elements and processing processes, and such modifications are also within the scope of the present invention. By the way. Hereinafter, such modifications will be described.

(Modification 1)
In the first to third embodiments, the average temperature Tave over each cycle is used. However, the minimum temperature Tmin or the maximum temperature Tmax may be reflected in the change amount ΔX (or the correction coefficient ε).

(Modification 2)
In the embodiment, the deterioration cycle number X is calculated, and the battery capacity CC _FULL is calculated according to the equation (2) based on the deterioration cycle number X. However, the deterioration cycle number X is calculated without calculating the deterioration cycle number X. The battery capacity C may be calculated directly according to the equation (12) as an index representing.
CC _FULL [i + 1] = CC _FULL [i] −ΔC [i] (12)
ΔC [i] = X [i] × α
That is, at least one of temperature, SOC, and cycle time _tCYC may be reflected in the change amount ΔC.

(Modification 3)
In Tave <Tr, ΔX (or ΔC) has no temperature dependence, but the present invention is not limited to this. For example, the temperature Tave may be divided into a plurality of temperature ranges, and at least one of M, Tr, and ΔT may have a different value for each temperature range. As an example, Tr is divided into two temperature ranges with a boundary as a boundary,
When T> Tr, M = M ₁ and ΔT = ΔT ₁
When T <Tr, M = M ₂ , ΔT = ΔT ₂
It is good.

  Alternatively, different arithmetic expressions may be used for each of a plurality of temperature ranges.

(Modification 4)
In the first to fourth embodiments, the average temperature Tave may be calculated separately for each charge cycle and discharge cycle.

(Modification 5)
In the embodiment, the charge / discharge cycle is illustrated as an example of “the battery has been charged and discharged with a predetermined amount of charge”, but the present invention is not limited thereto. For example, “the battery has been charged and discharged by a predetermined amount of charge” may be a charge cycle (discharge cycle). Therefore, each time a charge cycle (discharge cycle) is detected, an index X (for example, the number of deterioration cycles, battery Capacity) may be updated. Alternatively, “the battery has been charged and discharged by a predetermined amount of charge” may be a charge cycle or a discharge cycle, and thus the index X may be updated each time either the charge cycle or the discharge cycle is detected. .

  In this case, the average temperature Tave (maximum temperature, minimum temperature, etc.) may be calculated for each of the charge cycle and the discharge cycle, and the SOC range may be determined. Further, the charge cycle time and the discharge cycle time may be individually measured and reflected in the variation ΔX.

  Further, although the predetermined charge amount is the charge corresponding to the capacity of the battery, it is not limited to this. One half of the battery capacity may be set as the predetermined charge amount, and the determination method is arbitrary.

(Use)
Finally, the use of the battery management system 100 will be described. FIG. 21 is a diagram illustrating an automobile 300 including the battery management system 100. The vehicle 300 is an electric vehicle (EV), a plug-in hybrid vehicle (PHV), a hybrid vehicle (HV), or the like. Inverter 302 receives voltage V _BAT from battery management system 100, converts it to alternating current, supplies it to motor 304, and rotates motor 304. Further, at the time of deceleration such as when the brake is stepped on, the inverter 302 performs a regenerative operation and collects the current generated by the motor 304 in the battery 102 of the battery management system 100. In addition, the PHV and EV include a charging circuit that charges the battery 102 of the battery management system 100.

  FIG. 22 is a diagram illustrating an electronic device 400 including the battery management system 100. In addition to the battery management system 100, the electronic device 400 includes a PMIC (power management IC) 402, a processor 404, and other electronic circuits (not shown). The PMIC 402 is a plurality of integrated power supply circuits, and supplies an appropriate power supply voltage to the processor 404 and other electronic circuits.

  In addition, the battery management system 100 can be used for industrial equipment, industrial machines, household / factory power storage systems, elevator system power supplies, and the like.

  Although the present invention has been described using specific terms based on the embodiments, the embodiments merely illustrate the principles and applications of the present invention, and the embodiments are defined in the claims. Many variations and modifications of the arrangement are permitted without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 100 ... Battery management system, 102 ... Battery, 104 ... Charging circuit, 108 ... Load, 200 ... Remaining amount detection circuit, 202 ... Coulomb counter circuit, 206 ... SOC calculation part, 500 ... Degradation estimation circuit, 502 ... Cycle detection part, 504 ... Temperature detection circuit, 506 ... Deterioration calculation unit, 508 ... Cycle time measurement unit, 510 ... Average temperature detection unit, 512 ... Change amount calculation unit, 514 ... Index calculation unit, 520 ... First average temperature detection unit, 522 ... Second average temperature detection unit, 524 ... range determination unit, 526 ... first change amount calculation unit, 528 ... second change amount calculation unit, 530 ... index calculation unit, 540 ... average temperature detection unit, 542 ... range determination unit, 544 ... change amount calculation unit, 546 ... index calculation unit, 600 ... deterioration estimation circuit, 602 ... correction coulomb counter circuit, 604 ... cycle detection unit, 606 ... deterioration calculation , 608 ... Temperature detection circuit, 610 ... Cycle time measurement unit, 620 ... Current detection circuit, 622 ... Correction coefficient calculation unit, 624 ... Multiplier, 626 ... Register, 628 ... Adder, 300 ... Car, 302 ... Inverter, 304 ... Motor, 400 ... Electronic equipment, 402 ... PMIC, 404 ... Processor.

Claims (33)

A method for estimating the deterioration state of a rechargeable battery,
Generating a coulomb count value by integrating the charge / discharge current of the battery;
Monitoring the state of the battery;
Detecting that the battery is charged and discharged with a predetermined amount of charge based on the coulomb count value;
Each time charging / discharging of the predetermined charge amount is detected, an index X indicating the deterioration of the battery is represented by a change amount ΔX, a change according to the state of the battery measured in a period during which the predetermined charge amount is charged / discharged. Step to
An estimation method comprising:   The estimation method according to claim 1, wherein the state of the battery includes a temperature of the battery.   The estimation method according to claim 2, wherein the change amount ΔX depends on any one of an average temperature, a maximum temperature, and a minimum temperature over a period during which the predetermined charge amount is charged and discharged. The change amount ΔX is expressed by the formula (1) at least in the range of T> Tr.
ΔX = K × M ^{(T−Tr) / ΔT} (1)
However, K, M, Tr, and (DELTA) T are prescribed | regulated by a parameter, The estimation method of Claim 3 characterized by the above-mentioned.   The estimation method according to claim 4, wherein 20 ° C. ≦ Tr ≦ 30 ° C., 1 <M <3, 5 ° ≦ ΔT ≦ 20 °.   6. The estimation method according to claim 4, wherein ΔX = K in a range of T <Tr. The state of the battery includes the SOC (State Of Charge) of the battery,
The estimation method according to claim 1, wherein the change amount ΔX depends on the SOC. The state of the battery includes the SOC (State Of Charge) of the battery,
The estimation method according to claim 4, wherein the parameter K depends on the SOC. Measuring the time t required for charging and discharging the predetermined amount of charge;
The estimation method according to claim 1, wherein the change amount ΔX depends on the time t. Measuring the time t required for charging and discharging the predetermined amount of charge;
The estimation method according to claim 4, wherein the parameter K depends on the time t. The charge / discharge of the predetermined charge amount corresponds to one charge / discharge cycle,
The estimation method according to claim 1, wherein the index X represents the number of charge / discharge cycles.   The estimation method according to claim 1, wherein the index X represents a capacity of a battery. A deterioration estimation circuit for a rechargeable battery,
Based on a coulomb count value obtained by integrating the charge / discharge current of the battery, a cycle detection unit that detects that the battery is charged and discharged by a predetermined amount of charge,
A state monitoring circuit for monitoring the state of the battery;
Each time charging / discharging of the predetermined charge amount is detected, an index X indicating the deterioration of the battery is represented by a change amount ΔX, a change according to the state of the battery measured in a period during which the predetermined charge amount is charged / discharged. A deterioration calculation unit to be
A deterioration estimation circuit comprising:   The deterioration estimation circuit according to claim 13, wherein the state of the battery includes a temperature of the battery.   The deterioration estimation circuit according to claim 14, wherein the change amount ΔX corresponds to any one of an average temperature, a maximum temperature, and a minimum temperature over a period during which the predetermined charge amount is charged and discharged. The change amount ΔX is expressed by the formula (1) at least in the range of T> Tr.
ΔX = K × M ^{(T−Tr) / ΔT} (1)
However, the deterioration estimation circuit according to claim 15, wherein K, M, Tr, and ΔT are defined by parameters.   The deterioration estimation circuit according to claim 16, wherein 20 ° C. ≦ Tr ≦ 30 ° C., 1 <M <3, 5 ° ≦ ΔT ≦ 20 °.   18. The deterioration estimation circuit according to claim 16, wherein ΔX = K in a range of T <Tr. The state of the battery includes the SOC (State Of Charge) of the battery,
The deterioration estimation circuit according to claim 13, wherein the change amount ΔX depends on the SOC. The state of the battery includes the SOC (State Of Charge) of the battery,
The deterioration estimation circuit according to claim 16, wherein the parameter K depends on the SOC. A cycle time measuring unit for measuring a cycle time t required for charging and discharging the predetermined charge amount;
21. The deterioration estimation circuit according to claim 13, wherein the amount of change ΔX depends on the cycle time t. A cycle time measuring unit for measuring a cycle time t required for charging and discharging the predetermined charge amount;
21. The deterioration estimation circuit according to claim 16, wherein the parameter K depends on the cycle time t. The charge / discharge of the predetermined charge amount corresponds to one charge / discharge cycle,
The deterioration estimation circuit according to claim 13, wherein the index X represents the number of charge / discharge cycles.   The deterioration estimation circuit according to claim 13, wherein the index X represents a capacity of a battery. A rechargeable battery,
The deterioration estimation circuit according to any one of claims 13 to 24, which detects a state of the battery;
An electronic device comprising: A rechargeable battery,
The deterioration estimation circuit according to any one of claims 13 to 24, which detects a state of the battery;
An automobile characterized by comprising: A method for estimating the deterioration state of a rechargeable battery,
Generating a detection value according to the charge / discharge current of the battery;
Generating a correction coefficient according to at least one of the battery temperature, the battery SOC (State Of Charge), and the charge / discharge cycle time of the battery;
Multiplying the detected value by the correction coefficient to generate an increase in coulomb count value;
Adding the increase to the current coulomb count value;
Calculating a deterioration state of the battery based on the coulomb count value;
An estimation method comprising: A deterioration estimation circuit for a rechargeable battery,
A correction coulomb counter circuit for generating a correction coulomb count value;
Based on the corrected coulomb count value, a cycle detection unit that detects that the battery is charged and discharged by a predetermined amount of charge,
A deterioration calculating unit that changes a predetermined amount of an index X indicating battery deterioration each time the battery is charged and discharged with a predetermined charge amount;
With
The correction coulomb counter circuit corrects the amount of change in the correction coulomb count value according to at least one of temperature T, SOC, and cycle time _tCYC . A method for estimating the deterioration state of a rechargeable battery,
Generating a coulomb count value by integrating the charge / discharge current of the battery;
Incrementing the number of charge / discharge cycles CYC _CD when the battery is charged and discharged with a predetermined charge amount based on the coulomb count value;
When the rated capacity of the battery is set to CC _{FULL_RATED} , the battery capacity CC _{FULL_AGED} after deterioration is determined using the deterioration coefficient α,
CC _{FULL_AGED} = CC _{FULL_RATED} -α × CYC _CD
The step of calculating by
Correcting the deterioration coefficient α;
An estimation method comprising: The step of correcting the deterioration coefficient α includes
(I) calculating a current remaining coulomb count value CCNOW not considering battery deterioration;
CCNOW = CC _{FULL_RATED-} ACC
(Ii) calculating a current remaining coulomb count value CCNOW_EST1 in consideration of battery deterioration;
_{CCNOW_EST1 = CCNOW- (CC FULL_RATED -CC FULL_AGED} )
= CC _{FULL_AGED} -ACC
(Iii) The step of setting the value of CCNOW when the remaining coulomb count value CCNOW_EST1 becomes zero or the value of SOC_EST1 becomes zero as ERR_CC;
SOC_EST1 = CCNOW_EST1 / CC _{FULL_AGED} × 100
= (CC _{FULL_AGED−} ACC) / CC _{FULL_AGED} × 100
(Iv) updating the degradation coefficient α using ERR_CC;
The estimation method according to claim 29, comprising: The step of correcting the deterioration coefficient α includes
(I) calculating a current remaining coulomb count value CCNOW not considering battery deterioration;
CCNOW = CC _{FULL_RATED-} ACC
(Ii) calculating an estimated deteriorated battery capacity CC _{FULL_AGED_EST2} ;
CC _{FULL_AGED_EST2} = CC _{FULL_RATED−} CYC _CD × α × N
However, N is a constant larger than 1 (iii) Current remaining coulomb count value CCNOW_EST2 considering battery deterioration
A step of calculating
_{CCNOW_EST2 = CCNOW- (CC FULL_RATED -CC FULL_AGED_EST2} )
= CC _{FULL_AGED_EST2-} ACC
(Iv) When the remaining coulomb count value CCNOW_EST2 becomes zero, or the value of CCNOW when the SOC_EST2 value becomes zero, ERR_CC;
SOC_EST2 = CCNOW_EST2 / CC _{FULL_AGED_EST2} × 100
= (CC _{FULL_AGED_EST2−} ACC) / CC _{FULL_AGED_EST2} × 100
(V) updating the degradation coefficient α using ERR_CC;
The estimation method according to claim 29, comprising: The step of correcting the deterioration coefficient α includes
(I) calculating a current remaining coulomb count value CCNOW not considering battery deterioration;
CCNOW = CC _{FULL_RATED-} ACC
(Ii) calculating an estimated deteriorated battery capacity CC _{FULL_AGED_EST3} ;
CC _{FULL_AGED_EST3} = CC _{FULL_RATED} × M-CYC _CD × α × N
However, N> 1,0 <M <1
(Iii) Current remaining coulomb count value CCNOW_EST3 considering battery deterioration
A step of calculating
_{CCNOW_EST3 = CCNOW- (CC FULL_RATED -CC FULL_AGED_EST3} )
= CC _{FULL_AGED_EST3} -ACC
(Iv) a step of setting the value of CCNOW when the remaining coulomb count value CCNOW_EST3 becomes zero or the value of SOC_EST3 becomes zero as ERR_CC;
SOC_EST3 = CCNOW_EST3 / CC _{FULL_AGED_EST3} × 100
= (CC _{FULL_AGED_EST3−} ACC) / CC _{FULL_AGED_EST3} × 100
(V) updating the degradation coefficient α using ERR_CC;
The estimation method according to claim 29, comprising: The step of updating the deterioration coefficient α is calculated using the formula α ′ = (α + ERR_CC) / CYC _CD.
The estimation method according to claim 30, wherein the estimation method is based on the above.

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