Battery control device

Abstract

A battery control device comprising an internal resistance calculation unit (152) configured to calculate an internal resistance value of a battery (110), and controlling the battery (110) based on the internal resistance value calculated by the internal resistance calculation unit, comprising: an index calculation unit (1522) that calculates an index indicating a polarization voltage of the battery (110); and a determination unit that determines whether the index is equal to or more than a determination threshold (A), wherein, when the determination unit determines that the index is equal to or more than the determination threshold (A), the battery (110) is controlled based on the internal resistance value calculated when the index is less than the determination threshold (A) in a previous determination.

Description

Technical field

[0001] The present invention relates to a battery control device State of the art

[0002] A battery system mounted in an electric motor vehicle, such as an electric vehicle (EV), a plug-in hybrid electric vehicle (PHEV), and a hybrid electric vehicle (HEV), includes a battery controller to maximize battery performance. The battery controller detects a voltage, temperature, and current of the battery and calculates a state of charge (SOC), a state of health (SOH), and an input / output power of the battery based on the detected factors.

[0003] The battery's internal resistance increases as it deteriorates. Therefore, the battery's internal resistance is calculated in real time to appropriately calculate the battery's input / output performance. Alternatively, the ratio of the initial internal resistance to the internal resistance after deterioration is calculated as the SOH as a reference for battery replacement. As a method for calculating the battery's internal resistance, there are a method for calculating the internal resistance from the ratio of the battery voltage variation to the current variation, and a method for calculating the internal resistance based on an equivalent circuit model by modeling the battery's resistance component.

[0004] In the method for calculating the internal resistance based on the latter equivalent circuit, there is a need to determine each circuit parameter (internal resistance value) of the equivalent circuit model, which varies according to deterioration. Therefore, a method for extracting these circuit parameters with accuracy during charge / discharge is required. For example, PTL 1 discloses a technique for extracting each circuit parameter of the equivalent circuit model through an adaptive digital filter, along with a current and a voltage during charge / discharge. PTL 2 discloses a battery control device that determines a chargeable / dischargeable electric power of a rechargeable battery after a lapse of a predetermined period of time when a terminal voltage of the rechargeable battery changes due to charging / discharging of the rechargeable battery during the predetermined period of time.The battery control device calculates a specific amount of change in the terminal voltage caused by accumulation of electric charge in the rechargeable battery after the elapse of the predetermined period of time when charging / discharging the rechargeable battery is performed. Patent Application Publication No. 3 discloses a method for determining the open-circuit voltage of a storage battery, including determining operating parameters of the storage battery in the open-circuit state and determining the open-circuit voltage, each with an open-circuit voltage determination routine selected depending on the operating parameters. Citation listPatent literature PTL 1: JP 3747826 B2 PTL 2: DE 10 2014 116 424 A1 PTL 3: EP 1 589 346 A1 Summary of the inventionTechnical problem

[0005] However, the internal resistance characteristics of the battery are considered in various different ways according to the current flow pattern and the degradation. Therefore, an error caused by the inability to accurately model the internal resistance characteristics of the battery is generated in the equivalent circuit model of the battery according to the current flow pattern. Consequently, the internal resistance value (equivalent circuit parameter) and the SOH (degradation index) cannot be calculated accurately.

[0006] If the internal resistance characteristics are subjected to high-precision modeling to avoid the above problem, the equivalent circuit model will be complex, and a process with high computational load may be required. Furthermore, when various material types, including the positive and negative electrodes of the battery, are changed, there is a need to capture a battery parameter contained in a complex equivalent circuit model. The number of man-hours required for development becomes large. Solution to the problem

[0007] The above object is achieved by the invention according to independent claim 1. Further preferred embodiments are described in the dependent claims.Specifically, a battery control device having an internal resistance calculation unit configured to calculate an internal resistance value of a battery and controls the battery based on the internal resistance value calculated by the internal resistance calculation unit includes: an index calculation unit that calculates an index indicating a polarization voltage of the battery; and a determination unit that determines whether the index is equal to or more than a determination threshold, wherein, when the determination unit determines that the index is equal to or more than the determination threshold, the battery is controlled based on the internal resistance value calculated when the index is less than the determination threshold in a previous determination. Advantageous effects of the invention

[0008] According to the invention, it is possible to achieve an improvement in calculation accuracy of an internal resistance and an SOH of a battery. Brief description of the drawings [ Fig. 1] Fig. 1 is a diagram for describing a first embodiment. [ Fig. 2] Fig. Figure 2 is a diagram showing an example of a SOC table. [ Fig. 3] Fig. 3 is a diagram showing a circuit configuration of a unit cell control unit. [ Fig. 4] Fig. 4 is a block diagram showing a configuration of a control unit for the assembled battery. [ Fig. 5] Fig. 5 is a block diagram illustrating a configuration of an SOC calculation unit. [ Fig. 6] Fig. Figure 6 is a diagram showing an example of a correspondence relationship between the SOC and the OCV. [ Fig. 7] Fig. Figure 7 is a diagram showing an equivalent circuit of a unit cell. [ Fig. 8] Fig. Fig. 8 is a diagram showing a behavior of a voltage in a case where a charging current flows in the unit cell formed by the equivalent circuit of Fig. 7 is shown. [ Fig. 9] Fig. 9 is a block diagram showing a configuration of an internal resistance calculation determination unit. [ Fig. 10] Fig. 10 is a diagram to describe whether the calculation of the internal resistance is possible. [ Fig. 11] Fig. 11 is a block diagram showing a configuration of an SOH calculation unit. [ Fig. 12] Fig. Figure 12 is a diagram showing an example of an SOH calculation result. [ Fig. 13] Fig. 13 is a block diagram illustrating a configuration of the internal resistance calculation determination unit in a second embodiment. [ Fig. 14] Fig. Figure 14 is a chart showing an example of a moving average calculation. [ Fig. 15] Fig. 15 is a diagram illustrating a relaxation behavior of a polarization voltage. [ Fig. 16] Fig. 16 is a diagram illustrating an example of an SOH calculation result in the second embodiment. [ Fig. 17] Fig. 17 is a block diagram illustrating a configuration of the internal resistance calculation determination unit in the second embodiment. [ Fig. 18] Fig. 18 is a diagram illustrating an example of an SOH calculation result in a third embodiment. [ Fig. 19] Fig. 19 is a diagram showing a polarization voltage calculation value and a true polarization voltage value when it is turned on. [ Fig. 20] Fig. 20 is a diagram illustrating a configuration of the internal resistance calculation determination unit in a fourth embodiment. [ Fig. 21] Fig. 21 is a diagram showing an example of an SOH calculation result in the fourth embodiment. [ Fig. 22] Fig. 22 is a block diagram illustrating a configuration of a control unit of the assembled battery in a fifth embodiment. [ Fig. 23] Fig. 23 is a block diagram illustrating a configuration of the internal resistance calculation determination unit in the fifth embodiment. [ Fig. 24] Fig. 24 is a diagram illustrating an example of a data table of a polarization determination threshold in a sixth embodiment. Description of embodiments

[0009] Embodiments of the invention will be described below with reference to the drawings. In the embodiments described below, the description will be given by way of example in a case where a storage device constituting a power source of a hybrid electric vehicle (holding device) is applied.

[0010] The configuration of the embodiment described below can be applied even to a battery control circuit of a battery system that is a power source in a car such as a plug-in hybrid electric vehicle (PHEV) or an electric vehicle (EV) and an industrial vehicle such as a hybrid railway vehicle.

[0011] In the embodiment described below, the description will be given about an example in a case where a lithium-ion battery is applied to a storage device of a storage unit. A nickel-hydrogen battery, a lead-acid battery, an electric double-layer capacitor, and a hybrid capacitor can be used as the storage device. - First embodiment -

[0012] A first embodiment of the invention is based on Fig. 1 to 14 are described.

[0013] Fig. 1 is a diagram for describing a battery control device of the first embodiment, illustrating an exemplary configuration of an electric motor system of the hybrid electric vehicle. A battery system 100 is connected to an inverter 400 through relays 300 and 310. The inverter 400 supplies power from the battery system 100 to a motor generator 410. The inverter 400 and the motor generator 410 are controlled by a motor / inverter control unit 420. A vehicle control unit 200 determines how to distribute driving force based on battery information such as the SOC (state of charge) of the battery system 100, information from the inverter 400 and the motor generator 410, and information from an engine (not shown).

[0014] The configuration of the battery system 100 will be described. The battery system 100 includes an assembled battery 110 configured by a plurality of unit cells 111, a unit cell management unit 120 that monitors the state of the unit cell 111, a current detection unit 130 that detects a current flowing to the assembled battery 110, a voltage detection unit 140 that detects a total voltage of the assembled battery 110, an assembled battery control unit 150 that controls the assembled battery 110, and a memory unit 180 that stores information regarding battery characteristics of the assembled battery 110, the unit cell 111, and a unit cell group 112.

[0015] The assembled battery 110 is configured by electrically connecting a plurality of unit cells 111 (for example, a lithium-ion battery) in series, which can be charged and discharged with electric energy (DC power charge / discharge). The output voltage of one unit cell 111 is 3.0 to 4.2 V (average output voltage: 3.6 V). In this embodiment, the description will be given by way of example in a case where a correlation as shown in Fig. 6, between an open circuit voltage OCV (Open Circuit Voltage) and the SOC of the unit cell 111, but other voltage specifications may be applied.

[0016] In the unit cell 111 constituting the assembled battery 110, the management of the state and control of the unit cell 111 are performed by a predetermined number of groups. Fig. 1, the unit cells are divided into two unit cell groups 112a and 112b. The grouped unit cells 111 are electrically connected in series and form the unit cell group 112. The predetermined number of unit cells may be, for example, 1, 4, 6, and so on. Alternatively, the unit cells may be divided into multiple sections, such as a combination of 4 and 6. In the example shown in Fig. In the example shown in Figure 1, the predetermined number of unit cells is 4.

[0017] The unit cell management unit 120 monitors the state of the unit cells 111 that form the composite battery 110, as described above. The unit cell management unit 120 is configured by multiple unit cell control units 121a and 121b. A unit cell control unit 121 is assigned to the unit cell group 112, which is grouped as described above. The unit cell control unit 121 receives power from the assigned unit cell group 112 and operates. The unit cell control unit 121 monitors a battery voltage and a temperature of the unit cells 111 that form the unit cell group 112.

[0018] In Fig. 1, the unit cell control unit 121a and the unit cell control unit 121b are provided in correspondence with the unit cell group 112a and the unit cell group 112b. In this embodiment, for the sake of simplicity in the description, it is assumed that the unit cell group 112 is configured such that four cells 111 are electrically connected in series. Further, four unit cells 111 are configured to be monitored by one unit cell control unit 121.

[0019] The assembled battery control unit 150 receives the battery voltage and temperature of the unit cell 111 transmitted from the unit cell management unit 120, a current value flowing to the assembled battery 110 transmitted from the current detection unit 130, a total voltage value of the assembled battery 110 transmitted from the voltage detection unit 140, a diagnosis result of whether the unit cell 111 is overcharged or overdischarged, or an abnormal signal output in a case where a communication error occurs in the unit cell management unit 120. The assembled battery control unit 150 detects the state of the assembled battery 110 based on the input information.In addition, a result obtained by the process of the assembled battery control unit 150 is transmitted to the unit cell management unit 120 and the vehicle control unit 200.

[0020] The assembled battery control unit 150 and the unit cell management unit 120 transmit signals through a signal communication unit 160. An insulating member 170 such as a photocoupler is provided in the signal communication unit 160. The reason why the insulating member 170 is provided is that the operating power source is different in the assembled battery control unit 150 and the unit cell management unit 120. As described above, the unit cell management unit 120 is operated by the power from the assembled battery 110, but the assembled battery control unit 150 uses a battery (for example, a 12V battery) for an in-vehicle accessory as a power source.The insulation member 170 may be mounted in a circuit board of the unit cell management unit 120 or may be mounted in a circuit board of the control unit 150 of the assembled battery. Furthermore, the insulation member 170 may be omitted according to a system configuration.

[0021] The communication between the assembled battery control unit 150 and the unit cell control units 121a and 121b will be described. The unit cell control units 121a and 121b are connected in series in descending order of the potentials of the unit cell groups 112a and 112b, which are respectively monitored. A signal transmitted by the assembled battery control unit 150 is input to the unit cell control unit 121a through the signal communication unit 160, in which the insulation member 170 is provided. The output of the unit cell control unit 121a and the input of the unit cell control unit 121b are connected through the signal communication unit 160. The signal communication unit 160 transmits the signal. Further, in this embodiment, the insulation member 170 is not provided between the unit cell control unit 121a and the unit cell control unit 121b.However, the isolation element 170 can be provided.

[0022] The output signal from the unit cell control unit 121b is transmitted through the signal communication unit 160, in which the isolation element 170 is provided, to an input section of the control unit 150 of the composite battery. In this way, the control unit 150 of the composite battery and the unit cell control units 1211a and 121b are connected in a loop form through the signal communication unit 160. The loop connection can be called a cascade connection, a linking connection, or a series connection.

[0023] The memory unit 180 stores information such as the internal resistance characteristics, full-charge capacities, polarization resistance characteristics, deterioration characteristics, individual difference information, and a correspondence relationship (SOC table) between the SOC and OCV of the assembled battery 110, the unit cell 111, and the unit cell group 112. Further, in this embodiment, the memory unit 180 is configured to be installed outside the control unit 150 of the assembled battery or the unit cell management unit 120. However, the memory unit 180 may be provided in the control unit 150 of the assembled battery or the unit cell management unit 120.

[0024] Fig. 2 is a diagram illustrating an example of the SOC table stored in the memory unit 180. The SOC table is a data table for describing a correspondence relationship between the OCV of the unit cell 111 and the SOC of the unit cell 111 according to temperature. Similar to the SOC table, the memory unit 180 also stores various types of battery characteristic information such as the internal resistance characteristics and the polarization resistance characteristics as a data table describing a correspondence relationship with respect to various types of parameters such as the SOC and temperature. In this embodiment, the data table is further used as a correspondence relationship between the OCV and the SOC. However, the correspondence relationship between the OCV and the SOC may be expressed by a mathematical expression and is not limited to a format such as the data table.

[0025] Fig. 3 is a diagram illustrating a circuit configuration of the unit cell control unit 121. The unit cell control unit 121 includes a voltage detection circuit 122, a control circuit 123, a signal input / output circuit 124, and a temperature detection unit 125. The voltage detection circuit 122 measures a voltage between the terminals of each unit cell 111. The temperature detection unit 125 measures a temperature of the unit cell group 112. The control circuit 123 receives measurement results from the voltage detection circuit 122 and the temperature detection unit 125 and transmits the measurement results to the assembled battery control unit 150 through the signal input / output circuit 124.

[0026] In general, the unit cell control unit 121 further includes a circuit configuration to compensate for a variation in voltage and SOC between the unit cells 111 caused by self-discharge and a variation in consumption current. However, such a circuit configuration is already well known and is therefore Fig. 2 omitted.

[0027] The temperature detection unit 125 measures a temperature of the entire unit cell group 112 and treats the temperature as a representative temperature of the unit cells 111 of the unit cell group 112. Therefore, a temperature detection unit 125 is provided in the unit cell control unit 121. The temperature measured by the temperature detection unit 125 is used in various types of calculation to detect the state of the unit cell 111, the unit cell group 112, or the assembled battery 110. Further, the temperature detection unit 125 may be provided in each unit cell 111 to measure the temperature of each unit cell 111, and various types of calculation may be performed based on the temperature of each unit cell 111. However, in this case, since the number of temperature detection units 125 is large, the configuration of the unit cell control unit 121 becomes complicated by the number.

[0028] In Fig. 3, the temperature detection unit 125 is simply illustrated. In practice, a temperature sensor is installed in a temperature measurement target, and the temperature sensor outputs the temperature information as a voltage. The measurement result is transmitted to the signal input / output circuit 124 through the control circuit 123. The signal input / output circuit 124 outputs the measurement result to the outside of the unit cell control unit 121. A function of realizing such a series of flux is mounted in the unit cell control unit 121 as the temperature detection unit 125. Further, the voltage detection circuit 122 can be used to measure temperature information (voltage).

[0029] Fig. 4 is a block diagram illustrating a configuration of the control unit 150 of the assembled battery. Further, in Fig. 4 shows a configuration of SOC calculation and SOH calculation related to battery control in this embodiment. For simplicity, configurations of a diagnostic process on the unit cell 111 performed by the assembled battery control unit 150 and a process based on the abnormal signal output in a case where a communication error occurs in the unit cell management unit 120 are omitted from the drawing and description.

[0030] The assembled battery control unit 150 includes an SOC calculation unit 151, an internal resistance calculation determination unit 152, and an SOH calculation unit 153. The SOC calculation unit 151 receives the voltage of the unit cells 111 of the assembled battery 110 (an average voltage of the unit cells 111), the current flowing to the assembled battery 110, the temperature of the assembled battery 110, and the SOH (health status) output by the SOH calculation unit 153. The SOC calculation unit 151 calculates and outputs the SOC and the SOCv based on these inputs. The calculation processing of the SOC and the SOCv will be described below.

[0031] The internal resistance calculation determination unit 152 receives the voltage of the unit cells 111 of the composite battery 110, the current flowing into the composite battery 110, the temperature of the composite battery 110, the SOC, the SOCv, and the SOH. Based on these inputs, the internal resistance calculation determination unit 152 determines whether the SOH calculation is to be performed or not. Further, the SOC and the SOH calculated in the control unit 150 of the composite battery are transmitted to the vehicle control unit 200.

[0032] Fig. 5 is a block diagram showing a configuration of the SOC calculation unit 151. The SOC calculation unit 151 includes an SOCi calculation unit 1511, an SOCv calculation unit 1512, and a combination calculation unit 1513.

[0033] Based on the input current and a previous value (a calculation result before one cycle) of the SOC calculation result output from the combination calculation unit 1513 (a calculation result before one cycle), the SOCi calculation unit 1511 calculates the SOC (hereinafter referred to as SOCi) based on an integrated value of the current. The SOCi is calculated by the following expression (1). In expression (1), "SOCold" represents a previous value (a calculation result before one cycle) of the SOC, which is calculated by expression (8) described below. In addition, "ΔSOC" represents an amount of change in the SOC by the current I flowing from the previous calculation to the current calculation. "Qmax" represents a full charge capacity of the unit cell 111, and "ts" represents a control cycle (a sampling cycle of the current and voltage). SOCi=SOCold+ΔSOC where ΔSOC=100 x|x ts / Qmax

[0034] The SOCv calculation unit 1512 calculates the OCV based on the input voltage, current, and temperature, and calculates the SOC (hereinafter referred to as SOCv) corresponding to the calculated OCV from the calculated OCV and a correspondence relationship defined in Fig. 6 is shown.

[0035] Fig. Figure 7 is a diagram illustrating an equivalent circuit of the unit cell 111. The unit cell 111 is a circuit configuration in which a pseudo DC voltage source of OCV, which indicates the open-circuit voltage of the battery, Ro, which indicates an electrical resistance such as an electrode and an electrolyte solution, and a parallel connection of Rp and C, which model a resistance component (polarization component) corresponding to an electrochemical reaction of the battery, are connected in series.

[0036] Fig. Figure 8 shows a behavior of the voltage in a case where the charging current I flows in the unit cell 111 formed by the equivalent circuit of Fig. 7. As in Fig. As shown in Figure 8, when the charging current I flows, a voltage rise Vo (= I × Ro) with respect to the OCV occurs through Ro, and then a polarization voltage Vp (= Ip × Rp) slowly appears, which is a voltage rise caused by Rp. The OCV is calculated by the following expression (4) from the equation shown in Fig. 7 shown equivalent circuit. Vo=I×Ro Vp=Ip×Rp OCV=CCV−(Vo+Vp)

[0037] Furthermore, Ro and Rp in expressions (2) and (3) are values obtained by multiplying a rate of increase (%) of the internal resistance by the resistance values (RoInit, RpInit) when the unit cell 111 is released, as the following expressions (5) and (6). Regarding "RoInit" and "RpInit", the data table of RoInit and RpInit according to the SOC and the temperature is stored in advance in the working memory unit 180, and "RoInit" and "RpInit" are calculated from the data table based on the SOC and the temperature at the current moment. In addition, "Ip" can be obtained using a result obtained by applying a primary delay filter to a current value as in the following expression (7). In expression (7), "I" represents a current value, "ts" represents a sampling cycle, "τ" is a time constant, and "Ipold" represents "Ip" before a control cycle. Ro = RoInit × SOH / 100 Rp = RpInit × SOH / 100 Ip=I ×(ts / τ)+Ipold×(1−ts / τ)

[0038] The SOCv calculation unit 1512 calculates the OCV by the expression (4) and calculates the SOC corresponding to the OCV as SOCv, as shown in Fig. 6. In a case where the correlation of Fig. 6 is expressed as SOC = Map(OCV), the SOCv is obtained by applying the OCV calculated by expression (4) to Map(OCV).

[0039] The combination calculation unit 1513 calculates the SOC by the following expression (8) using the SOCi calculated by the SOCi calculation unit 1511, the SOCv calculated by the SOCv calculation unit 1512, the current, and the temperature as inputs. In expression (8), "w" represents a weight coefficient and is calculated, for example, by the following expression (9). SOC=w×SOCv+(1−w)×SOCi w=1 / (1+|I|×Ro)

[0040] As shown in the above expressions (8) and (9), when the current I is large, the weight coefficient w becomes small. Therefore, an eccentricity to the SOCi is increased. Conversely, when the current I is small, the weight coefficient w becomes large. Therefore, the eccentricity to the SOCv is increased. In this embodiment, in order to avoid an influence of an SOCv error accompanied by a resistance error when the current flows, the weight coefficient w is installed as expression (9), but the invention is not limited to this.

[0041] Fig. 9 is a block diagram illustrating a configuration of the internal resistance calculation determination unit 152. The internal resistance calculation determination unit 152 includes an internal resistance error detection unit 1521, a bias voltage determination unit 1522, and a correction determination unit 1523.

[0042] The internal resistance error detection unit 1521 determines whether there is an error in the resistance values ​​(Ro, Rp) in the SOCv calculation based on the SOC and the SOCv input from the SOC calculation unit 151. Specifically, in a case where an absolute value of a difference between the SOC and the SOCv is equal to or more than a predetermined value, it is determined that there is a need to calculate an internal resistance value (each circuit parameter in the equivalent circuit of Fig. 7) used in the SOCv calculation, and the determination result is output.

[0043] The polarization voltage determination unit 1522 calculates the polarization voltage Vp based on the SOC, current, voltage, and temperature, and determines whether the calculation of the internal resistance is possible based on an amplitude of the calculated polarization voltage Vp. Fig. 10 is a diagram for describing how the polarization voltage determination unit 1522 determines whether the calculation of the internal resistance is possible. A dashed line L1 indicates the calculated value of the polarization voltage, and a solid line L2 indicates a true value of the polarization voltage. During a period when the charging current flows for the first time, the polarization voltage Vp is gradually increased as time passes. At this time, the sign of the polarization voltage Vp is a positive sign. Even if a charging / discharging interruption state exists after the charging current is input, the polarization is relaxed in the interruption state. However, if a discharging current flows before the relaxation is completed, the polarization voltage is gradually increased again in a negative direction as time passes.

[0044] If the section of the state of charge of Fig. As viewed in Figure 10, in an initial region B in an energization time, a gap between the calculated value and the true value of the polarization voltage is small. However, the polarization voltage increases as the energization time is prolonged. In addition, it can be seen that the gap between the calculated value and the true value of the polarization voltage also increases (region C). Further, in order to shorten the interruption time after charging, the discharge current is set to flow before the polarization voltage is relaxed. Consequently, an influence of an error (calculation error) caused when the charging current flows remains when the discharging current flows (region D). Therefore, it can be seen that the polarization voltage is not accurately calculated when the discharging current flows (region E).In a region of long excitation time, as a cause of the deterioration of the calculation accuracy of the polarization voltage, another resistance component caused by the dispersion of lithium ions, besides the resistance components accompanied by the electrochemical reaction of the battery.

[0045] In area C, which is Fig. As shown in Figure 10, in which the polarization voltage is large and the polarization voltage cannot be accurately calculated, an error in the calculated internal resistance is large, and an error even in the SOH calculation based on the internal resistance also occurs. Furthermore, in a discharge period (region E), the polarization voltage caused during discharge remains before the discharge starts. Since the polarization voltage is still large, it can be determined that it is not possible to sufficiently ensure the calculation accuracy of the polarization voltage during a period in which the discharge current flows.

[0046] In this embodiment, as in Fig. Then, as shown in Figure 10, a predetermined threshold value (A on a positive side, -A on a negative side) is set in the bias voltage, and the internal resistance is not calculated under a condition that an absolute value of the bias voltage is large. Furthermore, in a case where the absolute value of the bias voltage before current flows is equal to or more than the threshold value, the internal resistance is not calculated during a current-flowing period.

[0047] The threshold value of polarization determination (hereinafter referred to as the polarization determination threshold value) may be set such that the current is allowed to flow in consideration of an actual operation pattern of a vehicle and the battery characteristics, and the polarization voltage generated at that time is estimated. Furthermore, regarding the polarization voltage as an index used in the determination of the polarization voltage determination unit 1522, the polarization voltage Vp, which is the voltage change caused by the polarization resistance component, may be calculated from Expression (3) or may be calculated by the following Expression (10). Vp=CCV−Vo−OCV

[0048] Further, when determining the polarization voltage, the absolute value of the polarization voltage obtained by expressions (3) and (10) is calculated and set as an index. In other words, it is determined whether the absolute value |Vp| of the polarization voltage Vp is equal to or greater than "A." Furthermore, the absolute value of the polarization voltage is not calculated, but the calculated polarization voltage Vp is used without change. It can be determined whether the polarization voltage Vp satisfies Vp≥A and Vp≤-A with respect to the polarization determination threshold A.

[0049] The correction determination unit 1523 determines whether to perform an internal resistance correction calculation based on the determination results of the internal resistance error detection unit 1521 and the polarization voltage determination unit 1522. As described above, the internal resistance error detection unit 1521 determines whether there is a need to correct the internal resistance value in a case where the absolute value of the difference between the SOC and the SOCv is equal to or more than the predetermined value. Furthermore, the polarization voltage determination unit 1522 determines whether the absolute value of the polarization voltage is equal to or more than the polarization determination threshold.The correction determination unit 1523 determines that the internal resistance correction calculation is performed in a case where it is determined in the internal resistance error detection unit 1521 that the internal resistance correction value is required and the absolute value of the polarization voltage is less than the polarization determination threshold. In other cases, it is determined that the internal resistance correction calculation cannot be performed.

[0050] Fig. 11 is a block diagram illustrating a configuration of the SOH calculation unit 153. The SOH calculation unit 153 includes an internal resistance correction unit 1531 and an SOH calculation unit 1532. The internal resistance correction unit 1531 receives a determination result of the internal resistance, SOC, and temperature calculation determination unit 152. In a case where it is determined by the internal resistance calculation determination unit 152 that it is not possible to perform the internal resistance calculation, the internal resistance correction unit 1531 reads the internal resistance value corresponding to the input SOC and temperature from an internal resistance table stored in the working storage unit 180 to correct the internal resistance value. The corrected result is output to the SOH calculation unit 1532.

[0051] As a correction method of the internal resistance value, for example, the following method is performed based on a difference between the SOC and the SOCv. In a case where a difference (SOC - SOCv) during charging is positive, the internal resistance value is corrected to decrease by a predetermined correction amount to reduce the difference. On the other hand, in a case where the difference (SOC - SOCv) during charging is negative, the internal resistance value is corrected to increase by a predetermined correction amount. In addition, in a case where the difference (SOC - SOCv) during discharging is positive, the internal resistance value is corrected to increase by a predetermined correction amount. On the other hand, in a case where the difference is negative, the internal resistance value is corrected to decrease by a predetermined correction amount.

[0052] The SOH calculation unit 1532 calculates the SOH by the following expression (11), for example, based on an internal resistance value Ro after correction and an initial internal resistance value Rolnit corresponding to the SOC and the temperature. Furthermore, in the example shown in expression (11), the SOH is set to a ratio of Ro and Rolnit, and may be a ratio of Rp and Rplnit. SOH=100×Ro / RoInit

[0053] On the other hand, in a case where the correction determination unit 1523 determines that the correction calculation of the internal resistance is not possible, the internal resistance correction unit 1531 does not correct the internal resistance value, but outputs the previous internal resistance value at which the polarization voltage is determined to be large. For example, in a case where the calculation is performed over an arbitrary calculation period, the internal resistance value calculated in a calculation period immediately before the calculation period in which the correction calculation is determined to be impossible is output. Therefore, in the case of the SOH calculated by Expression (11), the previous SOH at which the polarization voltage is determined to be large is also output.

[0054] Furthermore, the SOH calculated by the SOH calculation unit 1532 is fed back to the SOCv calculation unit 1512 in the SOC calculation unit 151 and used in calculating the SOCv in the next calculation period. Consequently, the internal resistance value correction is performed sequentially to reduce the difference between the SOC and the SOCv.

[0055] Fig. Figure 12 is a diagram showing an example of an SOH calculation result. Fig. Figure 12(a) shows time-sequential data of current (line LI) and voltage (line LV). Fig. 12(b) and Fig. 12(c) shows the polarization voltage and a calculation result of the SOH in a case where the current and voltage applied in Fig. 12(a). Furthermore, since current must flow to perform the internal resistance correction calculation, the resistance correction calculation is not performed during a break period in which current is not flowing. In this case, the SOH calculation unit 1532 outputs the SOH calculation result immediately before the break period.

[0056] First, the polarization voltage falls within a range of the polarization determination threshold (-A to A) in a previous period H1a of the discharge period H1. Therefore, the correction calculation of the internal resistance value is performed, and the SOH is gradually increased. In a later period H1b of the discharge period H1, the polarization voltage deviates from the polarization determination threshold (-A) (the case of |Vp| ≥ A is considered to be deviated). The correction calculation of the internal resistance value is interrupted at a deviation time, and the internal resistance value before the deviation from the polarization determination threshold is output. Consequently, the SOH calculated based on the internal resistance value is not updated during a period in which the polarization voltage deviates from the polarization determination threshold.The SOH of the same value as the SOH before the deviation from the polarization determination threshold is output.

[0057] After the interruption of the discharge period H1, the interruption period occurs. However, since the interruption period is short, a large portion of the polarization voltage remains before the current switching even at a time point P1 (before the discharge current flows) when the current switches from the interruption period to a charging period J1. Therefore, even if the charging current flows in the charging period J1, the SOH update is stopped, and the SOH (the SOH at a time point when the discharge period H1 ends) before the polarization determination is output.

[0058] In the case of the next discharge period H2, the previous interruption period is long. At the time the discharge period H2 starts, the polarization voltage is relaxed within the range of the polarization determination threshold. Therefore, when the discharge starts in the discharge period H2, the SOH update is performed. However, in a later period H2b of the discharge period H2, the polarization voltage deviates from the polarization determination threshold (-A). Therefore, the SOH is not updated.

[0059] Next, in the case of a charging period J2, the polarization voltage at a time P2 (before the charging current flows) immediately before the charging period J2 deviates from the polarization determination threshold. Therefore, similar to the case of the charging period J1, the SOH is not updated, and the SOH of the same value as the SOH immediately before the charging period J2 is output.

[0060] As described above, the assembled battery control unit 150 includes, as a battery control device, the internal resistance correction unit 1531 that calculates the internal resistance value of the assembled battery 110 and controls the assembled battery 110 based on the internal resistance value calculated by the internal resistance correction unit 1531. The polarization voltage determination unit 1522 of the assembled battery control unit 150 calculates an index indicating the polarization voltage of the assembled battery 110 and determines whether the calculated index is equal to or more than a predetermined threshold value. In this embodiment, for example, the polarization voltage Vp calculated based on Expression (3) or Expression (10) is used as the index indicating the polarization voltage.In this case, the polarization voltage Vp is calculated based on the current flowing to the battery, the voltage and / or the temperature.

[0061] If the polarization voltage Vp is determined as an index as |Vp| ≥ A with respect to the polarization determination threshold A, then the assembled battery 110 is controlled based on the internal resistance value calculated when |Vp| < A before the determination is satisfied. In this way, in a situation where a calculation error of the internal resistance value is large, it is possible to suppress a decrease in the calculation accuracy of the internal resistance and the state of health (SOH) of the internal resistance of the battery by using the internal resistance value calculated when |Vp| < A.

[0062] In this way, in this embodiment, in a case where the polarization voltage determined based on one or more factors (i.e., the polarization voltage Vp as the voltage variation by the polarization resistance component calculated by Expressions (3) and (10)) is determined as |Vp| ≥ A (polarization determination threshold), an error of the calculated value of the internal resistance is large. Therefore, the correction calculation of the internal resistance based on the difference between the SOC and the SOCv is not performed. In this case, it is possible to suppress a decrease in the calculation accuracy of the internal resistance of the battery and the state of health (SOH) of the internal resistance by using the internal resistance value calculated when |Vp| < A before the determination is satisfied.

[0063] As indicated by the symbol P1 of Fig. In addition, as shown in Figure 12, when it is determined that the polarization voltage Vp is equal to or more than a determination threshold (|Vp| ≥ A) at the time of non-energization (interruption period) before energization starts, the battery is controlled in the charging period J1 after energization starts based on the internal resistance value calculated when the polarization voltage is less than the determination threshold (|Vp| < A) before the determination. Therefore, even in a case where there is a need to be energized before the polarization voltage is released, it is possible to suppress a decrease in the calculation accuracy of the internal resistance of the battery and the state of health (SOH) of the internal resistance.

[0064] Furthermore, the internal resistance value is calculated based on a difference between two charging states that are different in the calculation method (for example, the difference between the SOC and the SOCv). The internal resistance value is corrected to make the difference between the SOC and the SOCv small. Consequently, as shown in Fig. As shown in Figure 12(c), in the case of |Vp| ≥ A (i.e., in a situation where the calculation error becomes large), the calculated value of the battery's state of health SOH is kept constant. Therefore, it is possible to prevent the state of health SOH from deviating from a true value. In this case, one of two states of charge (SOC and SOCv) is the state of charge SOCv, which is calculated based on the battery's open-circuit voltage OCV. - Second embodiment -

[0065] A second embodiment of the invention will be described with reference to Fig. 13 to 16. Furthermore, the configuration of the electric motor system of the hybrid electric vehicle in this embodiment is different from that shown in Fig. 1 of the first embodiment. The following description will be given focusing on different portions of the configuration of the first embodiment.

[0066] In the first embodiment, Vp is directly calculated from Expression (3) or Expression (10) and used as an index to determine whether the bias voltage is equal to or more than the predetermined value. On the other hand, in this embodiment, instead of directly calculating Vp, a current value flowing to the battery is used as an index to determine whether the bias voltage is equal to or more than the predetermined value.

[0067] Fig. Fig. 13 is a block diagram of the internal resistance calculation determination unit 152 in this embodiment. Only the configuration of a polarization voltage determination unit 1522a is different from the internal resistance calculation determination unit 152 shown in Fig. 9, although the polarization voltage is calculated from the expression (3) or expression (10) in the polarization voltage determination unit 1522 of Fig. 9, in the polarization voltage determination unit 1522a of this embodiment, a current value is input to calculate a moving average value of the current in an arbitrary section, and the moving average value of the current is used as a determination index of the polarization voltage.

[0068] The bias voltage can be varied in various ways according to the current flowing to the battery. Therefore, the amplitude of the bias voltage can be directly determined using the moving average value calculated from the current in a given section.

[0069] Fig. Figure 14 is a chart showing an example of a moving average calculation. In Fig. In Figure 14, line L30 represents an instantaneous current, and line L31 represents a moving average current. The moving average value of an arbitrary time window Tw is calculated according to the following expression (12) and is compared with the polarization determination threshold. Similar to the case of the first embodiment, the polarization determination threshold can be determined based on an actual operation pattern and an actual battery characteristic of a vehicle in which an electric motor system is mounted. [MATH. 1] Iave=∑i=x−TwxIi / Tw

[0070] Although the moving average in Fig. 14, lave obtained as a result of the primary delay filter on the current value can be used instead of the moving average value, as shown in the following expression (13). Here, "I" represents a current value, "ts" represents a sampling cycle, "τ" represents a time constant, and "lave_old" represents lave before a control cycle. Furthermore, Tw and τ of expressions (12) and (13) can vary according to the temperature of the battery. [MATH. 2] Iave=I×(ts / τ)+Iaveold×(1−ts / τ)

[0071] Fig. Figure 15 is a diagram showing a relaxation behavior of the polarization voltage according to temperature. Fig. 15(b) represents a transition of the current flowing to the battery and Fig. Figure 15(a) illustrates a battery voltage (CCV) transition. Line L41 indicates the case of low temperature, and a polarization relaxation time is t41. Line L42 indicates the case of room temperature, and the polarization relaxation time is t42. Line L43 indicates the case of high temperature, and the polarization relaxation time is t43. It can be seen that the polarization is relaxed and it takes a long time because the battery temperature is low. Tw and τ are set to values ​​that become large when the temperature is low and to values ​​that become small when the temperature is high. Therefore, a moving average value reflecting the relaxation behavior of the polarization voltage or the current value through the primary delay filter can be calculated, and the behavior of the polarization voltage can be expressed with more accuracy.

[0072] Fig. 16 is a diagram illustrating an example of an SOH calculation result in the second embodiment. Fig. Figure 16(a) shows time-sequential data of current (line LI) and voltage (line LV). Fig. 16(b) and Fig. 16(c) show the moving average current and a calculation result of the SOH in a case where the current and voltage measured in Fig. 16(a). Similar to the case of the first embodiment, the resistance correction calculation is not performed during the interruption period in which no current flows. The SOH calculation result in this case is output immediately before the interruption period starts.

[0073] First, the moving average current falls within a range of the polarization determination threshold (-A1 to A1) in the previous period H1a of the discharge period H1. Therefore, the correction calculation of the internal resistance value is performed, and the SOH is gradually increased. In the later period H1b of the discharge period H1, the moving average current deviates from the polarization determination threshold (-A1). The correction calculation of the internal resistance value is interrupted at a deviation time, and the internal resistance value before the deviation from the polarization determination threshold is output. Consequently, the SOH calculated based on the internal resistance value is not updated during a period in which the moving average current deviates from the polarization determination threshold. The SOH of the same value as the SOH before the deviation from the polarization determination threshold is output.

[0074] After the interruption of the discharge period H1, the interruption period occurs. However, since the interruption period is short, when the current switches from the interruption period to the charging period J1, the moving average current deviates from the polarization determination threshold even at time P3 (before the discharge current flows). Therefore, even if the charging current flows in the charging period J1, the SOH update is stopped, and the SOH (the SOH at the time when the discharge period H1 ends) before the polarization determination is output.

[0075] In the case of the next discharge period H2, the previous interruption period is long. At a time when the discharge period H2 starts, the moving average current is relaxed within the range of the polarization determination threshold. Therefore, when the discharge starts in the discharge period H2, SOH updates are performed. However, in a later period H2b of the discharge period H2, the moving average current deviates from the polarization determination threshold (-A1). Therefore, the SOH is not updated, but the SOH immediately before the start of the later period H2b is output.

[0076] Next, in the case of a charging period J2, the moving average current at a time P4 (before the charging current flows) immediately before the charging period J2 deviates from the polarization determination threshold. Therefore, similar to the case of the charging period J1, the SOH is not updated, and the SOH of the same value as the SOH immediately before the charging period J2 is output.

[0077] In this embodiment, instead of the polarization voltage Vp calculated by expressions (3) and (10) in the first embodiment, a value obtained by time-sequentially averaging the current flowing to the battery is calculated as an index indicating the polarization voltage of the battery. Then, based on whether the index is equal to or more than the polarization determination threshold (whether the index deviates from the polarization determination threshold), it is determined whether the polarization voltage is equal to or more than the predetermined value. In a case where it is determined that the polarization voltage is equal to or more than the predetermined value, the internal resistance correction calculation is not performed. Control is performed using the calculation value of the internal resistance before the polarization voltage is equal to or more than the predetermined value.In this way, in a situation where the error in the internal resistance correction calculation becomes large, the internal resistance correction calculation is not performed. Therefore, it is possible to suppress a decrease in the calculation accuracy of the internal resistance and the internal resistance state of health (SOH). Furthermore, it is possible to easily achieve the effect in a case where the average current value is obtained, compared to a case where the polarization voltage Vp is calculated. - Third embodiment -

[0078] A third embodiment of the invention is described with reference to Fig. 17 and Fig. 18. Furthermore, the configuration of the electric motor system of the hybrid electric vehicle in this embodiment is similar to that in Fig. 1 of the first embodiment. The following description will be given focusing on portions different from those of the first and second embodiments.

[0079] In the first embodiment, Vp is directly calculated as an index from Expression (3) or Expression (10). It is determined using the index whether the polarization voltage is equal to or more than the polarization determination threshold. Furthermore, in the second embodiment, instead of directly calculating Vp, it is determined whether the polarization voltage is equal to or more than the polarization determination threshold based on the current value flowing to the battery. On the other hand, in this embodiment, it is possible to determine whether the polarization voltage is equal to or more than the predetermined value with a method simpler than those of the first and second embodiments.

[0080] The polarization voltage becomes large as the current excitation time elapses. Therefore, in this embodiment, the current excitation time is counted. It is determined that the polarization voltage is equal to or more than the predetermined value based on whether the counted continuous excitation time is equal to or more than a predetermined value.

[0081] Fig. 17 is a block diagram of the internal resistance calculation determination unit 152 in this embodiment. A difference from the internal resistance calculation determination unit 152 in the first and second embodiments is that it is provided with an energization time measuring unit 1524. The energization time measuring unit 1524 receives the current and counts a continuous energization time when an absolute value of the current is equal to or more than the predetermined value and only one of the charging current and the discharging current is continuously flowing. The counted result is input to a polarization voltage determination unit 1522b.

[0082] In a case where the count result (continuous energization time) is equal to or more than the polarization determination threshold A2, the polarization voltage determination unit 1522b determines that the polarization voltage is large. In a case where it is determined that the polarization voltage is large, the internal resistance value before the polarization voltage is determined to be large is output as the internal resistance value of the battery, similar to the case of the first and second embodiments.

[0083] Fig. 18 is a diagram illustrating an example of an SOH calculation result in the third embodiment. Fig. Figure 18(a) shows time-sequential data of current (line LI) and voltage (line LV). Fig. 18(b) and Fig. 18(c) shows the counting result (continuous excitation time) and a calculation result of the SOH in a case where the current and voltage applied in Fig. 18(a). Similar to the case of the first embodiment, the resistance correction calculation is not performed during the interruption period in which no current flows. The SOH calculation result in this case is output immediately before the interruption period starts.

[0084] First, the continuous energization time is less than the polarization determination threshold (A2) in the previous period H1a of the discharge period H1. Therefore, the correction calculation of the internal resistance value is performed, and the SOH is gradually increased. In the later period H1b of the discharge period H1, the continuous energization time becomes equal to or more than the polarization determination threshold (A2) and deviates. The correction calculation of the internal resistance value is interrupted at a deviation time, and the internal resistance value before the deviation from the polarization determination threshold is output. Consequently, the SOH calculated based on the internal resistance value is not updated during a period in which the continuous energization time deviates from the polarization determination threshold. The SOH of the same value as the SOH before the deviation from the polarization determination threshold is output.

[0085] Then comes the interruption period (the absolute value of the current is equal to or less than the predetermined value). The count value of the energization time is reset to "0." When the interruption period ends and the charging period J1 arrives, the charging current starts flowing and the energization time is counted again. If the continuous energization time becomes equal to or more than the polarization determination threshold (A2) in a later period J1b of the charging period J1, the correction calculation of the internal resistance value is interrupted, and the SOH immediately before the correction calculation is interrupted is output. The discharge period H2 and the charging period J2 also exhibit similar behavior.

[0086] As described above, even in this embodiment, in a situation where the calculation error of the internal resistance is large, the correction calculation of the internal resistance is not performed, and the calculation value of the internal resistance before the continuous energization time becomes equal to or more than the polarization determination threshold (A2) is used. Therefore, similar to the case of the first and second embodiments, it is possible to suppress a decrease in the calculation accuracy of the internal resistance and the state of health (SOH) of the internal resistance. Further, in this embodiment, a time (continuous energization time) when the current flowing to the battery is energized is counted, and it is determined whether the polarization voltage is equal to or more than the polarization determination threshold based on the counted continuous energization time.Therefore, compared with the case of the first and second embodiments, it is possible to appropriately determine whether the polarization voltage is equal to or more than the polarization determination threshold with a simpler process. Fourth embodiment

[0087] A fourth embodiment of the invention will be described with reference to Fig. 19 to 21. Furthermore, the configuration of the electric motor system of the hybrid electric vehicle in this embodiment is similar to that shown in Fig. 1 of the first embodiment. The following description will be given focusing on portions different from those of the first to third embodiments.

[0088] In the first to third embodiments, a parameter is used as an index for determining the polarization voltage. In the first embodiment, for example, whether the polarization voltage is equal to or more than the predetermined value was determined only using Vp calculated from Expression (3) or Expression (10) as an index. On the other hand, in this embodiment, the amplitude of the polarization voltage is not determined from a parameter. However, the amplitude of the polarization voltage is determined, for example, by the polarization voltage calculated from Expression (3) or Expression (10) in the first embodiment, in parallel with the determination of the excitation time in the third embodiment.

[0089] In the following, further description will be given about an example in which the method of using the polarization voltage calculated by the expression (10) of the first embodiment as an index is used in parallel with the method of the third embodiment, but a combination of parallel methods is not limited to this.

[0090] In a case where the polarization voltage is calculated by subtracting Vo and OCV from the battery voltage (CCV) as Expression (10), the components of the polarization voltage that are difficult to model can be directly extracted without using a surrogate model. However, there is a problem that the calculation errors of Vo and OCV are included. In particular, in a case where an error is included in Ro used in the calculation of Vo, that is, a case where there is a gap between the internal resistance value detected by the control unit 150 of the assembled battery and the internal resistance value of the battery (actual control target), an error is generated in Vp calculated from Expression (10). Therefore, there is a possibility that the determination of whether the polarization voltage is large is not performed with accuracy.

[0091] Fig. 19 is a diagram showing an example in a case where such determination is not carried out accurately. Fig. 19 is a diagram showing the polarization voltage calculation value and an actual polarization voltage value at the time of excitation (charging / discharging). A gap occurs between the polarization voltage calculation value (line L51) and the actual polarization voltage value (line L52) due to an error contained in the internal resistance value. At the time of discharging, the polarization voltage calculation value is shifted to the positive side with respect to the actual polarization voltage value. At the time of charging, the polarization voltage calculation value is shifted to the negative side with respect to the actual polarization voltage value.

[0092] Therefore, in the later period H1b of the discharge period, even if the true polarization voltage value is less than the polarization determination threshold (-A) and deviates from a range of the threshold, the polarization voltage calculation value falls within the range of the polarization determination threshold. Even in the later period J1b of the charge period, a similar situation occurs. Consequently, even if the correction calculation of the internal resistance is not possible, it is erroneously determined that the correction determination is possible because the calculated polarization value falls within the threshold. In other words, it can be seen that the determination of the polarization voltage using Expression (10) during energization is undesirable.

[0093] Furthermore, in the first embodiment, in a case where the polarization voltage calculation value before the excitation starts deviates from the polarization determination threshold value, as shown by symbol P1 of Fig. 12, the calculation of the internal resistance is not performed. However, at the time the excitation starts, if the polarization determination is performed based on the polarization voltage at the moment the current flows, the polarization voltage calculation value deviates from the polarization determination threshold due to the error of the internal resistance. However, regarding this problem, the determination is performed using the polarization voltage before the current flows (for example, before one control cycle), instead of using the polarization voltage at the time the excitation starts. Consequently, since the current does not flow, Vo in Expression (10) becomes "0", and thus the polarization voltage can be correctly extracted. Consequently, the position can be correctly determined.

[0094] On the other hand, in a method for counting the energization time described in the third embodiment, the polarization voltage can be determined without being affected by an error such as the current, voltage, and internal resistance value. Therefore, in the method of the first embodiment, the polarization determination during energization can be performed with accuracy even in such a situation that the gap described above occurs. However, since the count result is cleared to zero after the current flows, it is not possible to determine whether the polarization voltage is relaxed during the interruption period in which the current does not flow, and it is not possible to determine whether the polarization voltage is large before the current flows.

[0095] Therefore, in the determination of the polarization voltage at the moment of energization in this embodiment, a process for determining whether an absolute value of the current at the time of position determination is equal to or less than a predetermined value is added to the method of the first embodiment. In other words, it is determined whether the absolute value of the current before the current flows is equal to or less than the predetermined value, and the polarization voltage before the current flows falls within the polarization determination threshold (referred to as first polarization determination). On the other hand, the method (referred to as second polarization determination) of the third embodiment is applied to the determination of the polarization voltage during energization.

[0096] Fig. Fig. 20 is a block diagram illustrating a configuration of the internal resistance calculation determination unit 152 in this embodiment. The internal resistance calculation determination unit 152 of Fig. 20 is configured to further add the excitation time measuring unit 1524 described in the third embodiment to the internal resistance calculation determination unit 152 ( Fig. 9) in the first embodiment. The count result (continuous energization time) output by the energization time measuring unit 1524 is input to a polarization voltage determination unit 1522c. The polarization voltage determination unit 1522c outputs a determination result indicating that calculation is not possible in a case where the internal resistance is determined to be incalculable from any one of the determination result (first polarization determination) by the current and Vp calculated by Expression (10) before the current flows and the determination result (second polarization determination) by the count result of the energization time.

[0097] Fig. 21 is a diagram showing an example of an SOH calculation result in the fourth embodiment. Fig. Figure 21(a) shows time-sequential data of current (line LI) and voltage (line LV). Fig. 21(b) to 21(d) represent the results of the polarization voltage, the continuous excitation time, and the SOH calculation result in a case where the current and the voltage shown in Fig. 21(a) are input. The current must flow to perform the correction calculation of the internal resistance value. Therefore, during the interruption period when the current does not flow, the resistance correction calculation is not performed. However, as the SSOH calculation result in this case, the SOH calculation result immediately before the interruption is output.

[0098] In the previous period H1a of the discharge period H1, the correction calculation is determined to be impossible in any of the determination result (first polarization determination) by the current and Vp calculated by Expression (10) before the current flows, and the determination result (second polarization determination) by the count result of the energization time. Therefore, the polarization voltage determination unit 1522c outputs a determination result that the correction calculation is performed. Consequently, the correction calculation of the internal resistance value is performed, and the SOH is increased as shown in Fig. 18(c). In a case where the energization time is counted and the count result of the continuous energization time in the later period H1b of the discharge period H1 is equal to or more than the polarization determination threshold A2, the second polarization determination is made that the correction calculation is not possible. Therefore, the polarization voltage determination unit 1522c outputs a determination result that the correction calculation is not possible. When the polarization voltage deviates from the polarization determination threshold, the correction calculation of the internal resistance value is interrupted at a deviation time, and the internal resistance value immediately before the deviation from the polarization determination threshold is output. Therefore, the update of the SOH is interrupted during a period in which the count result deviates from the polarization determination threshold.

[0099] Thereafter, since the interruption period is short, even if the interruption period exists, the polarization voltage (the polarization voltage indicated by the symbol P5) remains high before the current is switched. Therefore, even if the count value of the continuous excitation time is less than the polarization determination threshold value A2 in the charging period J1, the first polarization determination determines that the calculation of the internal resistance is not possible. As a result, the update of the SOH is interrupted and the SOH immediately before the polarization determination is output.

[0100] In the next discharge period H2, in a previous period H2a, the interruption period is long, and the polarization voltage is relaxed within the polarization determination threshold. Therefore, the SOH is updated. However, in the later period H2b, the count value of the continuous energization time becomes abnormal with respect to the polarization determination threshold A2. Therefore, the calculation of the internal resistance becomes impossible, and the SOH update is interrupted. In the charging period J2, the polarization voltage before the charging current is input deviates from the polarization determination threshold. Therefore, similar to the case of the charging period J1, the SOH is not updated, and the SOH immediately before the polarization determination is output.

[0101] As described above, in this embodiment, the polarization voltage determination unit 1522c calculates the polarization voltage calculation value by Expression (10) based on the voltage and temperature of the battery and the current flowing to the battery, and the energization time measurement unit 1524 calculates the continuous energization time, which is a time when the current flows to the battery. Then, as described above, the continuous energization time is applied as an index of the polarization voltage during energization, and the polarization voltage calculation value is applied as the polarization voltage before energization starts, so that an index suitable for the usage situation of the battery can be used as the index of the polarization voltage.

[0102] Then, the amplitude of the polarization voltage is determined based on these indices. If the index is equal to or greater than the polarization determination threshold, the battery is controlled based on the internal resistance value calculated before the polarization voltage becomes equal to or greater than the threshold. Therefore, it becomes possible to suppress a decrease in the battery's internal resistance and the calculation accuracy of the internal resistance's state of health (SOH).

[0103] In particular, comparing the case of Fig. 18 with the fall of Fig. 21 differs in the case of Fig. 21, the polarization voltage before the excitation starts in the charging periods J1 and J2 deviates from the polarization determination threshold. In the charging periods J1 and J2, the SOH update is not performed. On the other hand, in the case of Fig. 18 the polarization voltage immediately before the excitation starts is not considered. Even if the polarization voltage in the situation of Fig. 21(b), the update (correction of the internal resistance value) of the SOH is therefore carried out in the excitation times (J1a, J2a).

[0104] Furthermore, as the polarization voltage index, a value obtained by time-sequentially averaging the current flowing to the battery can be used in addition to the two types described above. Then, at least two of these three types of indexes can be used according to a usage situation of the battery. Furthermore, the polarization voltage indexes are not limited to the three types as long as the amplitude of the polarization voltage can be determined. Fifth embodiment

[0105] A fifth embodiment of the invention will be described with reference to Fig. 22 and Fig. 23. Furthermore, the configuration of the electric motor system of the hybrid electric vehicle in this embodiment is similar to that in Fig. 1 of the first embodiment. The following description will be given focusing on different portions of the configuration of the first to fourth embodiments.

[0106] In the first to fourth embodiments, although the SOC and SOCv are used to detect the calculation error of the internal resistance, an accumulation value of the current in the SOCi is included in the SOC, as shown in expressions (1) and (8). Therefore, in a case where an error is included in the current sensor, the current error is accumulated, and thus there is a possibility that the SOC error is expanded. Consequently, there is a concern that the calculation accuracy of the internal resistance will be reduced.

[0107] Therefore, in this embodiment, in order to reduce an influence of the current accumulation error as much as possible, the calculation error of the internal resistance is calculated by comparing a voltage measurement value and the battery voltage calculated using the Fig. 7, instead of detecting the calculation error of the internal resistance using the SOC and the SOCv, the internal resistance value is detected and the internal resistance value is corrected.

[0108] Fig. Fig. 22 is a block diagram illustrating a configuration of the control unit 150 of the assembled battery in this embodiment. A difference from Fig. 4 of the first embodiment is that a battery voltage estimation unit 154 is provided. The battery voltage estimation unit 154 calculates a battery voltage estimate (CCVmodel) based on the input current, the input temperature, the input SOC, and the input SOH as in the following expression (14). Further, in expression (14), the OCV is calculated from a correspondence relationship between the SOC and the OCV shown in Fig. 6, and Vo and Vp are calculated from expressions (2) and (3). CCVmodel=OCV+Vo+Vp

[0109] Fig. 23 is a block diagram illustrating a configuration of an internal resistance calculation determination unit 152a of the assembled battery control unit 150 shown in Fig. 22. An internal resistance error detection unit 1521a receives the measured voltage and the battery voltage estimated value CCVmodel calculated by the battery voltage estimation unit 154. The internal resistance error detection unit 1521a calculates a difference between the battery voltage estimated value CCVmodel and the CCV (voltage measured value) and outputs the calculated result to the correction determination unit 1523 as input. The polarization voltage determination unit 1522 outputs the determination of the polarization voltage in any of the first to fourth embodiments.The correction determination unit 1523 outputs a determination result of whether the calculation of the internal resistance is possible based on the difference input from the internal resistance error detection unit 1521a and the determination about the polarization voltage input from the polarization voltage determination unit 1522.

[0110] If the difference (CCVmodel - CCV) between the internal resistance value correction calculation based on the battery voltage estimate CCVmodel and the CCV (voltage measurement value) during charging is positive, the internal resistance value is corrected to be small. If the difference is negative, the internal resistance value is corrected to be large. On the other hand, if the difference between these values ​​is positive during discharging, the internal resistance value is corrected to be large. If the difference is negative, the internal resistance value is corrected to be small.

[0111] As described above, even if the battery voltage CCV is used instead of the SOC, the similar effect to that of the first embodiment can be achieved. In other words, in a case where the bias voltage becomes large and exceeds a predetermined threshold, the correction calculation of the internal resistance is interrupted, and the internal resistance value is controlled to be a calculation value of the internal resistance before (immediately before) it is equal to or more than the threshold. Therefore, it is possible to suppress a decrease in the calculation accuracy of the internal resistance of the battery and the state of health (SOH) of the internal resistance.

[0112] In this embodiment, a fault detection method using voltage instead of SOC was also described, but the invention is not limited to this. Unlike SOC and voltage, the resistance value can be directly detected. For example, a measured value R1 of the internal resistance value is calculated based on the current, voltage, and SOC by the following expression (15). R1=(CCV−OCV) / I

[0113] On the other hand, an initial value RO of the internal resistance of the battery is obtained by the following expression (16) based on the equivalent circuit of Fig. 7 calculated. RO=(VoO+VpO) / I where VoO=1×Rolnit and VpO=Ip×RpInit.

[0114] Furthermore, the SOH can be calculated by calculating a ratio of R1 and R0 as the following expression (17). SOH=100×R1 / R0

[0115] In this way, even in a case where the internal resistance is calculated directly besides the SOC and the voltage, it is possible to achieve the effect of suppressing a reduction in the calculation accuracy according to the determination via the polarization voltage similar to the case of the SOC and the voltage. - Sixth Embodiment -

[0116] Fig. Figure 24 is a diagram for describing the sixth embodiment of the invention. In the first to fifth embodiments, the polarization determination threshold is set to a constant value using the polarization voltage determination unit 1522. However, the amplitude and calculation accuracy of the polarization voltage vary according to a state of the battery. As shown in Fig. For example, as shown in Figure 15, when the battery temperature is lowered and as deterioration progresses, the polarization voltage is increased.

[0117] Therefore, if the polarization determination threshold is set constantly, the threshold will be set too strictly depending on a condition, and there is a possibility that the internal resistance correction calculation will almost not be performed. Conversely, if the threshold is set gently, there is a possibility that the internal resistance correction calculation will be performed under a condition under which the correction calculation should not be performed.

[0118] Therefore, in this embodiment, the polarization determination threshold is changed according to a state of the battery. In this embodiment, the description is given about temperature and SOH, which are considered to be largely influenced among the parameters for determining the behavior of the polarization voltage.

[0119] Fig. Figure 24 is a diagram showing an example of the data table of the polarization determination threshold according to temperature and SOH. In Fig. 24, the horizontal direction represents the SOH (%), and the vertical direction represents the temperature (°C). The polarization determination threshold is set to be large when the SOH is increased and large when the temperature is decreased. In this way, it is possible to accurately determine the polarization voltage using the threshold data table corresponding to the temperature and SOH, even under a condition where the temperature and SOH are different. Fig. 24, the data table also corresponds to temperature and SOC, but the invention is not limited thereto. The data table may be configured to correspond to current and SOC.

[0120] According to this embodiment, it is possible to suppress a decrease in the frequency of internal resistance correction calculation or a decrease in internal resistance calculation accuracy, which may occur in the first to fifth embodiments where the polarization determination threshold is kept constant. Therefore, control in a case where the threshold is exceeded, that is, control to set the internal resistance to a value calculated before it is equal to or more than the threshold without performing internal resistance correction calculation, can be accurately performed by accurately changing the threshold according to the battery state. Furthermore, it is possible to suppress a decrease in the calculation accuracy of the internal resistance of the battery and the state of health (SOH) of the internal resistance.

[0121] Furthermore, the description in this embodiment has been given about an example in a case where the data table of the threshold value corresponding to the temperature and the SOH is used with respect to the polarization voltage calculated directly by the expressions (3) and (10) described in the first embodiment and the fourth embodiment. However, the threshold value for the moving average current described in the second embodiment and the threshold value for the continuous energization time described in the third embodiment are also similarly stored as a data table corresponding to the temperature and the SOH, so that the polarization voltage can be determined with accuracy even under a condition where the temperature and the SOH are different.

[0122] Although various embodiments and modifications have been described above, the invention is not limited to these contents. Other aspects that can be considered to fall within the technical concepts of the invention are intended to be included within the scope of the invention. List of reference symbols 100 battery system 110 assembled battery 111 Unit cell 112, 112a, 112b unit cell group 120 unit cell management unit 121, 121a, 121b Unit cell control unit 122 Voltage detection circuit 123 Control circuit 124 Signal input / output circuit 125 Temperature recording unit 130 current detection unit 140 voltage detection unit 150 Control unit of the assembled battery 151 SOC calculation unit 152, 152a Calculation determination unit for the internal resistance 153 SOH calculation unit 154 Battery voltage estimation unit 160 Signal communication unit 170 insulation element 180 memory units 1511 SOCi calculation unit 1512 SOCv calculation unit 1513 Combination calculation unit 1521, 1521a Internal resistance fault detection unit 1522, 1522a, 1522b, 1522c polarization voltage determination unit 1523 Correction determination unit 1524 Excitation time measuring unit 1531 Correction unit for the internal resistance 1532 SOH calculation unit

Claims

[1] A battery control device comprising an internal resistance calculation unit (152) configured to calculate an internal resistance value of a battery (110), and controls the battery (110) based on the internal resistance value calculated by the internal resistance calculation unit, comprising: an index calculation unit (1522) that calculates an index indicating a polarization voltage of the battery (110); and a determination unit that determines whether the index is equal to or more than a determination threshold (A), wherein, when the determination unit determines that the index is equal to or more than the determination threshold (A), the battery (110) is controlled based on the internal resistance value calculated when the index is less than the determination threshold (A) in a previous determination. [2] The battery control device according to claim 1, wherein the index calculation unit (1522) calculates a polarization voltage calculation value as an index based on a voltage and / or a temperature of the battery (110) and a current flowing to the battery (110). [3] The battery control device according to claim 1, wherein the index calculation unit (1522) calculates a value obtained by time-sequentially averaging a current flowing to the battery (110) as an index. [4] The battery control device according to claim 1, wherein the index calculation unit (1522) calculates an energization time of the battery (110) as an index. [5] Battery control device according to claim 1, wherein the index calculation unit (1522) calculates at least two of a first index, which is a polarization voltage calculation value calculated on the basis of a voltage and a temperature of the battery (110) and a current flowing to the battery (110), a second index, which is a value obtained by time-sequentially averaging the current flowing to the battery (110), and a third index, which is an energization time of the battery (110), and the determination unit determines whether each index calculated by the index calculation unit (1522) is equal to or more than each determination threshold value (A) set for each index. [6] The battery control device according to claim 2 or 3, wherein, when the determination unit determines that the index is equal to or more than the determination threshold (A) in a non-energization time before the battery (110) starts to be energized, the battery (110) is controlled after the energization starts based on the internal resistance value calculated when the index is less than the determination threshold (A) before the determination. [7] The battery control device according to any one of claims 1 to 6, wherein the internal resistance calculation unit (152) calculates the internal resistance value based on a difference between two charging states by different calculation methods. [8] The battery control device according to claim 7, wherein one of the two charging states is a charging state in which the internal resistance value is calculated based on an open circuit voltage of the battery (110). [9] The battery control device according to any one of claims 1 to 6, wherein the internal resistance calculation unit (152) calculates the internal resistance value based on a difference between a working voltage measurement value of the battery (110) and a working voltage calculation value calculated based on a current flowing to the battery (110). [10] The battery control device according to any one of claims 1 to 6, wherein the determination threshold (A) is set according to a temperature of the battery (110) and / or a deterioration of the battery (110).

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