Battery management system

Abstract

Battery management system, featuring: a device (100) with: a secondary battery (400); and a first electronic control unit (600) designed to detect a current flowing through the secondary battery (400), wherein the first electronic control unit (600) is designed to determine a change in an imbalance of the ion concentration in an electrolyte of the secondary battery (400) based on a profile of the detected current, wherein the first electronic control unit (600) is designed to calculate an evaluation value related to a deterioration in the function of the secondary battery (400) due to charging or discharging based on an estimated imbalance of the ion concentration, and wherein the first electronic control unit (600) is designed to store profile information for the evaluation value; and a battery management terminal (10) with: a second electronic control unit (14) designed to query the evaluation value history information of the secondary battery (400) from the first electronic control unit (600) prior to replacement of the secondary battery (400), wherein the second electronic control unit (14) is designed to determine required properties of a replacement secondary battery based on the evaluation value history information; and an information unit (12) designed to communicate the required properties determined by the second electronic control unit (14), wherein the first electronic control unit (600) is designed to store a total value of the evaluation values ​​within a specified time period as an integrated value (ΣD) of the evaluation value, wherein an evaluation value which lies in a range between a first specified value (D0) and a second specified value (D1) is not added to the integrated value (ΣD) of the evaluation value, and an evaluation value which lies outside the range from the first specified value (D0) to the second specified value (D1) is added to the integrated value (ΣD) of the evaluation value, and wherein the second electronic control unit (14) is designed to query the integrated value (ΣD) of the evaluation value as the trend information for the evaluation value from the first electronic control unit (600).

Description

BACKGROUND OF THE INVENTION 1. Field of the invention

[0001] The invention relates to a battery management system which determines which properties are required of a replacement secondary battery when a secondary battery is replaced. 2. Description of the related technology

[0002] To protect the environment, hybrid vehicles, electric vehicles, and similar technologies have been developed in recent years. These vehicles are equipped with batteries, such as lithium-ion secondary batteries. These batteries are collected when the vehicles are decommissioned or when the batteries are replaced during repairs. The collected batteries are then repurposed through processes such as recycling, reuse, and remanufacturing.

[0003] Recycling is a process for reusing a battery by disassembling it. Reuse is a process in which a battery pack or accumulator set is directly reused. Rebuilding is a process in which an accumulator set is taken apart, usable battery cells are removed, and then reassembled into a new accumulator set.

[0004] JP 2012 - 155 981 A describes a technique by which, when reusing a storage battery or battery pack, its performance is maximized according to the characteristics of a reused battery, by utilizing information about differences in battery performance resulting from a charging and discharging control situation during primary use, by sending the information to a device in which the reused battery is used.

[0005] The technique described in JP 2012-155981A involves adapting the properties of a device using a reused battery to the properties of the reused battery. However, if, for example, the way a user uses the device deviates from typical usage due to user preferences, the battery may not meet the user's requirements after replacement.

[0006] In particular, a temporary (reversible) increase in the battery's internal resistance can occur if a battery is subjected to prolonged discharge with a high current outflow (hereinafter also referred to as "high-level discharge"). If such a usage situation persists, it leads to a deterioration of the battery's performance. If a user prefers to use a battery in a situation where high-level discharge is likely to occur, a replacement battery is advantageously one with good resistance to high-level discharge. The same applies to charging a battery with a high current inflow (hereinafter also referred to as "high-level charging").

[0007] However, JP 2012 - 155 981 A does not investigate whether a reused battery may be unsuitable for a use required by a user, nor does it read the user's usage history from a device using a reused battery; therefore, there is room for improvement here.

[0008] Further relevant prior art is disclosed in the publications EP 2 631 663 A1, US 7 710 073 B2, US 2012 / 0 191 578 A1, US 2014 / 0 046 536 A1, DE 10 2004 007 904 A1 and US 2010 / 0 241 376 A1. SUMMARY OF THE INVENTION

[0009] The aforementioned problems and the resulting task are solved by the subject matter of claim 1. Advantageous embodiments of the invention are the subject matter of the dependent claims that follow.

[0010] The invention provides a battery management system that is able to select a replacement battery suitable for use by a user of a device.

[0011] A battery management terminal according to an explanatory aspect of the present disclosure is intended for a secondary battery mounted in a device. The device comprises a first electronic control unit. The first electronic control unit is designed to detect a current flowing through the secondary battery. The first electronic control unit is designed to determine a change in an imbalance of the ion concentration in an electrolyte of the secondary battery based on a current detection profile. The first electronic control unit is designed to calculate an evaluation value related to a deterioration in the function of the secondary battery due to charging or discharging, based on a computationally determined or estimated change in an imbalance of the ion concentration. The first electronic control unit is designed to store trend information related to the evaluation value.The battery management terminal includes a second electronic control unit and an information unit. The second electronic control unit is designed to retrieve the secondary battery's evaluation value history from the first electronic control unit before the battery is replaced. Based on this evaluation value history, the second electronic control unit determines the required characteristics of a replacement secondary battery. The information unit communicates the characteristics that the second electronic control unit has determined to be necessary.

[0012] If, in the above design, the use of the device results in a tendency to easily lead to an imbalance in the ion concentration in the electrolyte of the secondary battery, it is possible to inform a user of the properties required of a replacement secondary battery in view of such an effect when a replacement is due.

[0013] The usage history of a battery during the use of the device to which the secondary battery is attached is recorded, and it is possible to read the usage history when the battery is replaced; therefore, it is possible to choose a replacement battery that is suitable for the user's use of the device.

[0014] The second electronic control unit can be designed to detect an imbalance in the charging or discharging frequency of the device based on historical data related to the evaluation value. The second electronic control unit can also be designed to communicate the characteristics of a secondary battery suitable for addressing the imbalance as required properties.

[0015] If the use of the device involves a predominance of high-level charging or high-level discharging, the above control makes it possible to inform the user about the properties of a secondary battery suitable for this use.

[0016] The device may further include a consumer that receives an output from the secondary battery. The first electronic control unit may be configured to lower the upper limit for the secondary battery's output to the consumer when an integrated evaluation value exceeds a permissible value, compared to when the integrated evaluation value is at or below the permissible value. The first electronic control unit may store the permissible value. The second electronic control unit may be configured to rewrite a stored permissible value to a value greater than the stored permissible value when a secondary battery with the required characteristics is installed as a replacement battery in the device.

[0017] With the aforementioned design, the second electronic control unit resets the permissible value in such a way that limiting the device's output after battery replacement is made more difficult, allowing the device to continue to exhibit high performance.

[0018] Furthermore, the information unit can be a display.

[0019] A battery management system according to a further explanatory aspect of the present disclosure comprises a device and a battery management terminal. The device includes a secondary battery and a first electronic control unit. The first electronic control unit is designed to detect a current flowing through the secondary battery. The first electronic control unit is designed to determine a change in an imbalance of the ion concentration in an electrolyte of the secondary battery based on a current detection profile. The first electronic control unit is designed to calculate an evaluation value related to a deterioration in the performance of the secondary battery due to charging or discharging, based on a computationally determined or estimated change in an imbalance of the ion concentration.The first electronic control unit is designed to store historical information about the evaluation value. The battery management terminal includes a second electronic control unit and an information unit. Before replacing the secondary battery, the second electronic control unit is designed to retrieve the historical information about the secondary battery's evaluation value from the first electronic control unit. Based on this historical information, the second electronic control unit determines the required characteristics of a replacement secondary battery. The information unit is designed to communicate the characteristics that the second electronic control unit has determined to be necessary.

[0020] If, in the above design, the use of the device results in a tendency to easily lead to an imbalance in the ion concentration in the electrolyte of the secondary battery, it is possible to inform a user of the properties required of a replacement secondary battery in view of such an effect when a replacement is due.

[0021] The usage history of a battery during the use of the device to which the secondary battery is attached is recorded, and it is possible to read the usage history when the battery is replaced; therefore, it is possible to choose a replacement battery that is suitable for the user's use of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Features, advantages and the technical and industrial significance of embodiments of the invention are described below with reference to the accompanying drawings, in which the same reference numerals denote the same elements and in which: Fig. 1 is a view showing the design of a battery management system according to one embodiment; Fig. 2 is a graph that schematically represents the charging and discharging pattern of an excessive discharge; Fig. 3 is a graph that schematically represents the charging and discharging pattern of an overcharge; Fig. 4 is a graph showing the distribution of a battery deterioration evaluation value D in the case of a small imbalance with respect to charging or discharging; Fig. 5 is a graph showing the distribution of a battery deterioration evaluation value D in the case of a large imbalance of charging or discharging; Fig. 6 is a functional block diagram of an ECU 600; Fig. 7 is a flowchart that represents a battery replacement selection procedure that is executed in the battery management system; Fig. 8 is a flowchart that shows a manufacturing process in a factory, with which a qualitative classification is carried out during reuse; Fig. 9 is a time scheme that schematically shows an example of time-dependent changes to an upper discharge power limit WOUT, a battery deterioration evaluation value D, a setpoint E, and an integrated battery deterioration value ΣD; and Fig. 10 is a table that presents an example where the fuel consumption figures are improved depending on the battery used. DETAILED DESCRIPTION OF EXECUTION FORMS

[0023] An embodiment of the present invention is described below with reference to the accompanying drawings. In the following description, identical reference numerals denote identical components. Their designations and functions are also identical. Therefore, their detailed descriptions are not repeated.

[0024] Fig. Figure 1 is a view showing the design of a battery management system according to the present embodiment. As shown in Fig. As shown in Figure 1, the battery management system is implemented by a terminal 10 and a vehicle 100. The terminal 10 is designed to communicate with the vehicle 100. A battery inventory database 22 can be located in a battery reconditioning plant 20 or the like and be capable of communicating with the terminal 10.

[0025] The vehicle 100 has a power control unit (PCU) 300, a battery 400, a drive motor 500 and an electronic vehicle control unit (ECU) 600 connected to these components.

[0026] The in Fig. The vehicle (100) shown in Figure 1 is an electric vehicle to which the drive motor 500 is attached. However, the invention is not limited to the vehicle shown in Figure 1. Fig. The term is not limited to the vehicle shown in the illustration, but can be applied to any vehicle that drives using electrical energy, for example a hybrid vehicle which, in addition to the drive motor 500, also has an internal combustion engine attached.

[0027] The Battery 400 is a battery pack in which several modules, each containing multiple lithium-ion secondary battery cells, are connected in series to form a single unit. The positive electrode of each lithium-ion secondary battery cell is made of a material capable of reversibly encapsulating or releasing lithium ions (hereinafter also referred to as "lithium salt") (for example, from a lithium-containing oxide). During a charging process, the positive electrode releases lithium salt into an electrolytic solution, and during a discharging process, it encapsulates lithium salt in the electrolytic solution. The negative electrode of each lithium-ion secondary battery cell is made of a material capable of reversibly encapsulating or releasing lithium salt (for example, carbon).During the charging process, the negative electrode traps lithium salt in the electrolytic solution and releases lithium salt into the electrolytic solution during the discharging process.

[0028] Motor 500 is a three-phase AC motor and is powered by electrical energy stored in battery 400. The driving force of motor 500 is transmitted to drive wheels (not shown).

[0029] The ECU 600 includes a control unit 651 and a memory unit 652. The ECU 600 is designed to execute predefined arithmetic operations based on maps and programs stored in the memory unit 652.

[0030] A voltage sensor 601, a current sensor 602, and a temperature sensor 603 are provided in the battery 400. The voltage sensor 601 detects the voltage between the two ends of the battery 400 (hereinafter referred to as "battery voltage VB"). The current sensor 602 detects the current flowing through the battery 400 (hereinafter also referred to as "charging and discharging current I"). In the following description, the charging and discharging current I is a positive value during discharging and a negative value during charging. The temperature sensor 603 detects the temperature of the battery 400 (hereinafter also referred to as "battery temperature TB"). These sensors output detection results to the ECU 600.

[0031] In this vehicle design, there is a situation where the internal resistance of battery 400 temporarily (reversibly) increases and the output voltage of battery 400 decreases if a deep discharge of battery 400 persists. It is clear that the imbalance of the lithium salt in the electrolyte solution due to a deep discharge is one of the factors responsible for the decrease in output voltage. If the condition of the temporarily increased internal resistance of battery 400 persists due to the deep discharge, irreversible deterioration of battery 400's function will occur.

[0032] Whether a deep discharge persists depends on how the user drives the vehicle. If the 400 battery deteriorates and its performance decreases, replacement should be considered. If a user frequently uses the battery in situations where deep discharge is likely, it is advantageous to replace it with a battery that has good resistance to deep discharge. The same applies to charging a battery with a high current flow (hereinafter also referred to as "deep charging").

[0033] In the battery management system according to the present embodiment, a technique is employed which involves prompting the user to select a suitable battery when replacing it. This is done by informing the user of the required characteristics of a battery suitable for their use. More precisely, an evaluation value indicating user usage is calculated in the vehicle 100, and the historical information for this evaluation value is stored in the vehicle 100. A battery management ECU 14 of a dealer terminal or a factory terminal reads the historical information for the evaluation value from the vehicle when a user requests a battery replacement.Based on the read history information, the battery management ECU 14 selects a replacement battery suitable for user use and informs the user, via display unit 12, which properties the replacement battery must have. The information channel is not limited to the display; an audible instruction can also be used. Display unit 12 and audible instructions are examples of information units.

[0034] The control unit 651 of the ECU 600 estimates or determines changes in the ion concentration in the electrolyte of the battery 400 based on the history of values ​​acquired by the current sensor 602 and calculates an evaluation value related to the deterioration of the battery 400's function due to charging or discharging, based on the estimated changes in an imbalance of the ion concentration. The storage unit 652 stores the history information for the evaluation value.

[0035] In this way, the historical information for the calculated and stored evaluation value is used in Terminal 10. Terminal 10 is located at a dealer or in a battery reconditioning facility. Terminal 10 contains the battery management ECU 14 and the display unit 12. When it is time to replace battery 400, the battery management ECU 14 retrieves the historical information for the evaluation value of battery 400 from storage unit 652 before the replacement and determines, based on this information, which properties are required for a replacement battery. The display unit 12 informs the user of the result of the battery management ECU 14's determination. The battery before replacement is the battery already installed in the vehicle. The replacement battery is a battery that is newly installed in the vehicle.This means that replacing the battery 400 consists of exchanging the battery for the replacement battery.

[0036] If the use of the vehicle 100 is such that it is prone to high-level discharge, high-level charging or the like, or if it is such that it is prone to an imbalance of the ion concentration in the electrolyte of the secondary battery, the above design makes it possible to inform the user which properties are required of a replacement secondary battery 400 in view of such an effect when a replacement is due.

[0037] As an example of the evaluation value described above, a battery deterioration evaluation value D can be used, which is described in Japanese patent no. 4494453, in published Japanese patent application no. 2013-051115 (JP 2013-051115 A) or in published Japanese patent application no. 2013-214372 (JP 2013-214372 A).

[0038] The imbalance in ion concentration resulting from charging or discharging decreases over time. In short, the battery deterioration evaluation value D is a value indicating the degree of remaining ion imbalance and is calculated using the following mathematical expression (1). D(N)=(1−A×ΔT)×D(N−1)+(B / C)×I×ΔT

[0039] D(N) and D(N-1) denote a current evaluation value D and a last evaluation value D calculated one calculation cycle prior, respectively. A denotes a forgetting factor, and ΔT denotes the calculation cycle time of the evaluation value D. B denotes the current coefficient, C denotes the current limit, and I denotes a battery current. The forgetting factor A becomes larger as the diffusion rate of lithium ions in the battery increases or as the cycle time ΔT lengthens. The forgetting factor A, the current coefficient B, and the limit C can be generated in the form of a characteristic map 25, which yields values ​​when the battery temperature TB and the battery's state of charge (SOC) are input.

[0040] The first term of mathematical expression (1) indicates that the evaluation value D approaches zero over time. The second term indicates that the evaluation value D increases due to discharge and decreases due to charging. Because I < 0 during charging, the evaluation value D is negative in the case of overcharging.

[0041] Fig. Figure 2 is a graph that schematically represents the charging and discharging pattern of an excessive discharge. Fig. Figure 3 is a graph that schematically represents the charging and discharging pattern of excessive charging. If this is in Fig. If the two shown patterns of excessive discharge persist, the evaluation value D will be a positive value. If this occurs in Fig. If the 3 shown patterns of excessive charging persist, the evaluation value D will be a negative value.

[0042] An integrated battery deterioration value ΣD is used as a value corresponding to the degree of progressive damage to battery 400. The calculation of the integrated battery deterioration value ΣD from the evaluation value D is now described. Fig. Figure 4 is a graph showing the distribution of the battery deterioration evaluation value D in the case of a small imbalance of charging or discharging. Fig. Figure 5 is a graph showing the distribution of the battery degradation evaluation value D in the case of a large imbalance between charging and discharging. Fig. 4 and Fig. 5. The battery degradation evaluation value D is stored at constant time intervals, and the course of the distribution of the values ​​stored in a given time period is shown.

[0043] If the evaluation value D lies within the range between a predefined value D0 and a predefined value D1, the correlation between the battery deterioration evaluation value D and the measure of progressive damage to battery 400 is low and the imbalance is small, as shown in Fig. Figure 4 shows that the evaluation value D, which lies in the range between the specified value D0 and the specified value D1, is not used to calculate the integrated battery degradation value ΣD. Therefore, the integrated battery degradation value ΣD neither increases nor decreases, but remains the same value. Fig. 4. The distribution of the evaluation value D for the last specified time period (for example, 14 days) shows that the integrated battery deterioration value ΣD for this specified time period is zero, and a small preponderance of high-level charging or high-level discharging is indicated.

[0044] If, on the other hand, as in Fig. As shown in Figure 5, if the evaluation value D lies outside the range between the specified value D0 and the specified value D1, then the imbalance is determined to be large. The evaluation value D that lies outside the range between the specified value D0 and the specified value D1 is used to calculate the integrated battery degradation value ΣD. Fig. 5. If the distribution of the evaluation value D for the last specified time period (for example, 14 days) is shown, the integrated battery degradation value ΣD for the specified time period will be a positive value, indicating predominant use for deep discharge. In contrast, in the case of the pattern that is Fig. 5 different, if the integrated battery degradation value ΣD becomes a negative value, predominant use for high-level charging is indicated.

[0045] The integrated battery degradation value (ΣD) is stored in the vehicle's memory unit for each predefined period from the start of battery use until immediately before its replacement. The history of the integrated battery degradation value (ΣD) is analyzed by reading the data. This makes it possible to determine which discharge usage patterns the vehicle user prefers. The charging pattern depends on the characteristics of the region where the vehicle is used (for example, whether there are hills, whether a fast-charging station is available, etc.). Therefore, by analyzing the history of the integrated battery degradation value (ΣD), a characteristic usage pattern may be found in a region where the vehicle is primarily used.The trend of the integrated battery deterioration value ΣD is also the trend information for the battery deterioration evaluation value D.

[0046] How the integrated battery degradation value ΣD is calculated in the vehicle is simply described with reference to the block diagram.

[0047] Fig. Figure 6 is a functional block diagram of the ECU 600. The in Fig. The six functional blocks shown can be implemented by hardware or by software. The ECU 600 includes a computing unit 610, a settings unit 620, and a control unit 630.

[0048] The computing unit 610 calculates the battery degradation evaluation value D resulting from a change in the imbalance of the lithium salt. The setting unit 620 variably controls a setpoint E resulting from the integrated battery degradation value ΣD. The setpoint E is used to determine whether the battery output should be limited. The control unit 630 is a section that limits the electrical input / output power of the battery 400 as a result of the setpoint E. The details of the control unit 630 are described later in an alternative embodiment concerning the limitation of the electrical input / output power. Now, the computing unit 610 and the setting unit 620, which are necessary to calculate the integrated battery degradation value ΣD, are described.

[0049] The ECU 610 comprises a processing unit 611, a storage unit 612, and a processing unit 613. The processing unit 611 calculates the state of charge (SOC) of the battery 400 from the charging and discharging current I. The processing unit 613 calculates the battery degradation evaluation value D (a current value) at intervals of one processing cycle time using the mathematical expression (1) described above, based on the discharge current value I, the battery temperature TB, and the battery degradation evaluation value D (a previous value) stored in the storage unit 612. The storage unit 612 stores the battery degradation evaluation value D calculated in the processing unit 613.

[0050] The setting unit 620 comprises an integration unit 621, a storage unit 622, and a setpoint setting unit 623. The integration unit 621 calculates the integrated battery degradation value ΣD. Specifically, the integration unit 621 calculates the total value of the battery degradation evaluation values ​​D within the last predefined time period (for example, 14 days) as the integrated battery degradation value ΣD. A method for calculating the integrated battery degradation value ΣD is not limited to this configuration.

[0051] If the battery deterioration evaluation value D lies in the range from the specified value D0 (< 0) to the specified value D1 (> 0), the correlation between the battery deterioration evaluation value D and the degree of progressive damage to battery 400 is low, as described in reference to Fig. 4 and Fig. As described in section 5, the integration unit 621 does not add the battery degradation evaluation value D to the integrated battery degradation value ΣD. However, if the battery degradation evaluation value D lies outside the range from the specified value D0 (< 0) to the specified value D1 (> 0), then the integration unit 621 adds the battery degradation evaluation value D to the integrated battery degradation value ΣD.

[0052] Memory unit 622 stores the integrated battery degradation value ΣD, which was calculated by integration unit 621. Memory units 612 and 622 are located in Fig. 1 is represented jointly as the storage unit 652, and the other sections, which perform arithmetic processing, are in Fig. 1 jointly represented as control unit 651.

[0053] The information about the course of the evaluation value D, which is calculated as described above and stored in the vehicle, can be read and used by the battery management system for the purpose of selecting a suitable replacement battery when a battery replacement takes place.

[0054] Fig. Figure 7 is a flowchart representing a battery replacement selection procedure executed within the battery management system. This flowchart process is used, for example, by the [unclear text] in Fig. The battery management ECU 14 shown in Figure 1 is executed when the user who wants to replace the battery drives the vehicle to a dealer and the dealer's terminal is connected to the vehicle ECU 600.

[0055] As in Fig. 1 and Fig. As shown in Figure 7, in S301 the battery management ECU 14 communicates with the vehicle ECU 600 and retrieves the integrated battery deterioration value ΣD. The integrated battery deterioration value ΣD is a type of historical information related to the evaluation value D. If a positive or negative side predominates in the evaluation value D, the battery 400 is damaged, and the integrated battery deterioration value ΣD is a value that indicates the degree to which the damage has progressed.

[0056] Subsequently, the battery management ECU 14 in S302 determines, based on the history information for the integrated battery degradation value ΣD, whether there is a strong predominance of charging or discharging of the battery,

[0057] If the integrated battery degradation value ΣD is a value calculated based on the battery degradation evaluation values ​​D within the last specified time period (for example, 14 days), the battery degradation evaluation value ΣD is recorded for each specified time period. In S302, the sum of the integrated battery degradation values ​​ΣD recorded for the corresponding specified time periods is calculated, and it only needs to be determined that the imbalance is large if the absolute value of the sum of the integrated battery degradation values ​​ΣD exceeds a specified threshold.

[0058] If S302 determines that the imbalance is not large (NO), the procedure proceeds to S303, and it is determined that a general-purpose battery will be used as a replacement. In S304, the quality of the replacement battery corresponding to the determination result is displayed on display unit 12. If S302 determines that the imbalance is large (YES), the process proceeds to S305.

[0059] In S305, the battery management ECU 14 determines, based on the sign of the integrated battery degradation value ΣD, whether the polarity of a high-level charge and discharge indicates excessive charging or excessive discharging. If the polarity in S305 indicates excessive discharging (if the sign is +), the process proceeds to S306; while the process proceeds to S307 if the polarity indicates excessive charging (if the sign is -).

[0060] In S306, it is determined that a battery of a quality resistant to over-discharge should be used as a replacement battery. In S308, the quality of the replacement battery corresponding to the determination is displayed on display unit 12. In contrast, in S307, it is determined that a battery of a quality resistant to over-charging should be used as a replacement battery. In S309, the quality of the replacement battery corresponding to the determination is displayed on display unit 12.The batteries described are of general quality, of a quality resistant to excessive discharge, and of a quality resistant to excessive charging; however, batteries possessing such qualities can be produced in advance by changing the density of the negative electrodes or the like during the design of the batteries.

[0061] When process S304, S308, or S309 ends, the process of the flowchart ends. Processes S310 through S313 are optional and are described later in the description of the alternative embodiment.

[0062] As described above, the battery management ECU 14 in vehicle 100 detects an imbalance between the frequency with which high-level charging occurs and the frequency with which high-level discharging occurs, based on the course of the integration value ΣD, which is a type of course information for the evaluation value D (S302), and the properties of the battery 400 (for example, the quality of the battery) that are suitable for the imbalance in the event frequency are set as the required properties and communicated on the display unit 12 (S304, S308, S309).

[0063] If the use of the battery 400 results in a predominance of high-level charging or high-level discharging in the vehicle 100, the control described above makes it possible to inform a user or a technician at a dealer or factory of the characteristics of the battery 400 that are suitable for use.

[0064] In S303, S306, S307, which in Fig. Figure 7 illustrates a general-purpose battery, a battery resistant to over-discharging, and a battery resistant to over-charging. It also describes how batteries possessing these qualities can be manufactured in advance by modifying the density of the negative electrodes or similar factors during the battery design process. Another method for manufacturing batteries according to quality is to sort them, for example, recycled batteries.

[0065] If Terminal 10 is in Fig. If the battery management ECU is a factory terminal, it retrieves information about the evaluation value D from a scrapped vehicle or a vehicle whose battery has not yet been replaced. If the batteries of these vehicles are reusable or reuse products, information about the evaluation value D and information indicating resistance to high-grade charging / discharging is stored, along with battery identification information, in the battery inventory database 22 of the battery reconditioning plant 20. Battery identification information includes, for example, the value of an ID tag or similar. The rate of increase of high-grade resistance can be calculated from a battery current and battery voltage and recorded in the vehicle as an example of the information indicating resistance to high-grade charging / discharging.The rate of increase of high-grade resistance is the rate of increase of battery resistance when high-grade charging / discharging takes place.

[0066] Fig. Figure 8 is a flowchart showing a manufacturing process in a factory where reused batteries are sorted by quality as they are reused. As shown in Fig. As shown in Figure 8, at the beginning, in S401, a technician in the battery recycling plant queries battery information from a vehicle to which a battery pack that is to be disposed of is attached, by connecting a communication cable to the vehicle.

[0067] In S402, the internal resistance, the battery's full charge capacity, and similar parameters are measured, and it is determined whether the battery is reusable. If S402 determines that the battery is not reusable, it is recycled in S405, and the process ends. Conversely, if S402 determines that the battery is reusable, the process continues to S403.

[0068] In S403, the battery is classified based on the rate of increase in its resistance to deep discharge. This rate can be calculated using data accumulated while the battery is installed in the vehicle, or it can be measured during a deep charge / discharge cycle performed at the factory. A battery whose rate of increase in deep discharge resistance is less than a predefined threshold is assigned to the class of batteries with resistance to excessive discharge. The same applies to deep charging.

[0069] This classification can be carried out based on a predetermined value of a battery or can be carried out based on an actual measured value obtained from a test by extracting a cell.

[0070] Once the classification in S403 is complete, a battery is refurbished in S404 as a reuse product, and the process ends.

[0071] An alternative embodiment is described below. If the condition where the internal resistance of battery 400 is temporarily increased persists due to a sustained high-rate discharge, irreversible deterioration of battery 400's function will occur. To avoid this situation, a sustained high-rate discharge must be counteracted. Therefore, the ECU 600 sets an upper charge power limit WIN and an upper discharge power limit WOUT (both in watts) as a result of the battery 400's condition. The actual charge power and discharge power of battery 400 are controlled so that they do not exceed the upper charge power limit WIN and the upper discharge power limit WOUT, respectively. Conversely, if the prevention of a sustained high-rate discharge is counteracted too strongly, there is a risk that the vehicle performance required by the user will not be adequately demonstrated.

[0072] In the alternative embodiment, in combination with the fact that the battery suitable for use by the user is selected as a replacement battery, the vehicle exhibits the vehicle performance behavior required by the user as far as possible by rewriting control data for the vehicle in such a way that the upper charging power limit WIN and the upper discharging power limit WOUT are raised.

[0073] First, the limitation of the charging and discharging power carried out in the vehicle is again discussed with reference to Fig. 6 described. The in Fig. The control unit 630 shown in Figure 6 limits the charging and discharging power. The setpoint E is defined as a parameter that is compared with the battery degradation evaluation value D for the purpose of carrying out this control. The setpoint adjustment unit 623 reads the integrated battery degradation value ΣD, which is stored in the memory unit 622, and variably controls the setpoint E in response to the integrated battery degradation value ΣD.

[0074] The control unit 630 controls the actual discharge power (hereinafter referred to as "actual discharge power P") in response to the result of the comparison between the battery degradation evaluation value D and the setpoint E. The control unit 630 limits the discharge of the battery 400 (hereinafter referred to as the "WOUT limit") by lowering the upper discharge power limit WOUT when the condition is met that the battery degradation evaluation value D exceeds the setpoint E (hereinafter also referred to as the "limit condition"). This WOUT limit counteracts deterioration of the battery 400 due to deep discharge.

[0075] The control unit 630 includes a detection unit 631 and a limiting unit 632. The detection unit 631 determines whether the limiting condition described above is met. The limiting unit 632 sets the upper discharge power limit (WOUT) to a lower value when the limiting condition is met than when the limiting condition is not met. The limiting unit 632 controls the PCU 300 so that the actual discharge power P does not exceed the upper discharge power limit (WOUT). Thus, the actual discharge power P is more strictly limited when the limiting condition is met than when it is not.

[0076] Fig. Figure 9 is a time scheme that schematically shows an example of time-dependent changes to an upper discharge power limit WOUT, a battery deterioration evaluation value D, a setpoint E, and an integrated battery deterioration value ΣD.

[0077] As in Fig. 6 and Fig. As shown in Figure 9, in the period before time t1, when the integrated battery degradation value ΣD is less than a permissible value K, the setpoint E is adjusted to a maximum value Emax, which is higher than a reference value Ebase by a predefined amount. Conversely, in the period after time t1, when the integrated battery degradation value ΣD exceeds the permissible value K, the setpoint E is gradually (stepwise) reduced from the maximum value Emax to the reference value Ebase in response to the integrated battery degradation value ΣD.

[0078] The reference value Ebase is a value set based on the assumption that irreversible deterioration of the battery 400 due to deep discharge is prevented. In contrast, the maximum value Emax is a value set within the range in which a required battery life (a service life required for the battery 400, for example, 10 years) can be guaranteed, assuming deep discharge is permissible.

[0079] Before time t1, the integrated battery degradation value ΣD is less than the permissible value K, so the setpoint E is set to the maximum value Emax. Therefore, the battery degradation evaluation value D becomes less than the setpoint E, and the WOUT limit is not applied.

[0080] When the integrated battery degradation value ΣD reaches the permissible value K at time t1, the reduction of the setpoint E begins. When the battery degradation evaluation value D exceeds the setpoint E at time t2, the WOUT limit is activated. As a result, excessive discharge is prevented, and the battery degradation evaluation value D decreases. When the battery degradation evaluation value D becomes less than the setpoint E (reference value Ebase) at time t3, the WOUT limit begins to decrease. When the integrated battery degradation value ΣD becomes less than the permissible value K at time t4, the setpoint E is gradually increased again to the maximum value Emax.

[0081] In cases where the setpoint E is fixed, the limit condition is already met as soon as the battery deterioration evaluation value D exceeds the fixed value even once, and the WOUT limit intervenes. In this case, it is possible to counteract irreversible deterioration of battery 400 due to deep discharge, which would impair vehicle performance. For this reason, the setting unit 620 increases the setpoint E to the maximum value Emax, which is greater than the reference value Ebase, as long as the integrated battery deterioration value ΣD, which corresponds to the degree of advanced deterioration in battery 400, exceeds the permissible value K. This ensures vehicle performance by allowing battery deterioration within the range that guarantees the required battery life.

[0082] If, on the other hand, the integrated battery degradation value ΣD exceeds the permissible value K, the setting unit 620 initiates an intervention of the WOUT limit by lowering the setpoint E from the maximum value Emax to the reference value Ebase. Thus, the required battery life can be properly ensured by counteracting a deterioration in the battery 400's function due to deep discharge.

[0083] As described above, the WOUT limit intervenes as a result of the fact that the integrated battery degradation value ΣD exceeds the permissible value K in the vehicle. Fig. Figure 9 shows the waveforms for the WOUT limit; however, the WIN limit also intervenes during charging as a result of the integrated battery degradation value ΣD becoming negative and smaller than an allowable value L (a negative value).

[0084] In the alternative embodiment, when the battery is replaced with a battery of a quality that is resistant to high-level discharge or a battery of a quality that is resistant to high-level charging, the battery's performance is utilized by making intervention by the WOUT limit or the WIN limit more difficult through a change in the setting, so that the permissible value K and the permissible value L are increased. Therefore, in the embodiment, which is an alternative to the present embodiment, processes S310 to S313, indicated by the solid line, are replaced by the process of Fig. 7 added, which is executed by the battery management system.

[0085] It will be revisited Fig. Reference is made to S308, where, after the notification that the quality resistant to excessive discharge is required as a property of a replacement battery, the process of waiting for the battery replacement to be completed is carried out in S310, and when the replacement is complete, the process of S312 is carried out. In S312, the battery management ECU 14 issues a command to the vehicle ECU 600 so that the discharge-side permissible value K, stored in memory unit 652, is rewritten to a larger (increased) value K1. After the battery replacement, it is thus more difficult for the vehicle to receive the WOUT limit, as in Fig. 9 is shown, so that the vehicle is able to drive in such a way as to fulfill a requirement of the user.

[0086] During charging, as in the case of discharging, the permissible value L for the integrated battery degradation value ΣD is also set to a negative side, as in Fig. Figure 9 is shown. If the integrated battery degradation value ΣD becomes less than the permissible value L, the WIN limitation is executed. After it has been communicated that the quality resistant to overcharging is the required characteristic of a replacement battery, the process of waiting for the battery replacement to be completed in S311 is carried out in S309, and when the replacement is complete, the process of S313 is executed. In S313, the battery management ECU 14 issues a command to the vehicle ECU 600 so that the charging-side permissible value L, which is stored in memory unit 652, is rewritten to the value L1, which has been increased as shown in Figure 9. Fig. Figure 9 shows that after the battery is replaced, the vehicle is more difficult to receive the WIN limit, thus enabling the vehicle to generate electrical power or be charged, thereby fulfilling a user requirement.

[0087] With the above design, the battery management ECU 14 sets the permissible value to an increased value, so that the output limitation of the vehicle 100 after the battery replacement can no longer occur so easily, allowing the vehicle 100 to continue to show its performance.

[0088] A model case for improving fuel consumption figures is described as an example in which the vehicle is able to demonstrate the behavior. Fig. Table 10 is an example where fuel consumption figures improve due to the use of a battery. Fig. 10, just as in the embodiment in a first comparative embodiment and a second comparative embodiment, describes a use by a user in which overcharging is predominant. In the embodiment, the battery used is of a quality that is highly resistant to overcharging; in the first comparative embodiment, the battery of general quality is used; and in the second comparative embodiment, the battery used is of a quality that is not very resistant to overcharging.

[0089] In this alternative embodiment, the permissible value L is set according to a usage battery, where the frequency of intervention by the input / output limit (WIN limit) is 1 in the embodiment where the battery is replaced with an optimal battery. Therefore, an input / output limit occurs 1.5 times as often in the first comparative embodiment, where the non-optimal battery is used, and 2 times as often in the second comparative embodiment. This indicates that electrical power is more easily recovered during engine regeneration in this embodiment than in the first and second comparative embodiments, and indicates improved fuel consumption figures.

[0090] To easily measure the imbalance of a user's usage, the frequency with which a battery input / output limit occurs during charging and the frequency with which a battery input / output limit occurs during discharging are counted separately, and based on which count value is large, it can be determined whether excessive charging or excessive discharging is taking place.

[0091] Fig. Figure 1 shows an example in which the device which uses the battery is a vehicle. However, the device need not be a vehicle, and the invention is applicable to any device as long as a battery in the device is replaced.

[0092] The embodiments described above serve for illustrative purposes and are in no way limiting. The scope of the invention is defined by the appended claims and not by the description above. The scope of the invention is intended to encompass all modifications within the scope of the appended claims and their equivalents.

Claims

Battery management system comprising: a device (100) with: a secondary battery (400); and a first electronic control unit (600) designed to detect a current flowing through the secondary battery (400), wherein the first electronic control unit (600) is designed to determine a change in an imbalance of the ion concentration in an electrolyte of the secondary battery (400) based on a profile of the detected current, wherein the first electronic control unit (600) is designed to calculate an evaluation value related to a deterioration in the function of the secondary battery (400) due to charging or discharging based on an estimated imbalance of the ion concentration, wherein the first electronic control unit (600) is designed toto store historical information on the evaluation value; and a battery management terminal (10) comprising: a second electronic control unit (14) designed to query the historical information on the evaluation value of the secondary battery (400) from the first electronic control unit (600) prior to replacement of the secondary battery (400), wherein the second electronic control unit (14) is designed to determine required properties demanded of a replacement secondary battery based on the historical information on the evaluation value; and an information unit (12) designed to communicate the required properties determined by the second electronic control unit (14), wherein the first electronic control unit (600) is designed to store a total value of the evaluation values ​​within a specified time period as an integrated value (ΣD) of the evaluation value.wherein an evaluation value that lies in a range between a first predefined value (D0) and a second predefined value (D1) is not added to the integrated value (ΣD) of the evaluation value, and an evaluation value that lies outside the range from the first predefined value (D0) to the second predefined value (D1) is added to the integrated value (ΣD) of the evaluation value, and wherein the second electronic control unit (14) is designed to query the integrated value (ΣD) of the evaluation value as the trend information for the evaluation value from the first electronic control unit (600). Battery management system according to claim 1, wherein the second electronic control unit (14) is designed to detect an imbalance in the frequency with which charging or discharging takes place in the device (100) based on the history information for the evaluation value, and the second electronic control unit (14) is designed to communicate properties of a secondary battery suitable for the imbalance as the required properties. Battery management system according to claim 1 or 2, wherein the device (100) further comprises a consumer which receives an output from the secondary battery (400), wherein the first electronic control unit (600) is designed to lower an upper limit for the output of the secondary battery (400) to the consumer when the integrated value (ΣD) of the evaluation value exceeds a permissible value, compared to when the integrated value (ΣD) of the evaluation value is at or below the permissible value, the first electronic control unit (600) stores the permissible value, and the second electronic control unit (14) is designed to rewrite a stored permissible value to a value greater than the stored permissible value when a secondary battery having the required properties is installed as a replacement battery in the device (100). Battery management system according to one of claims 1 to 3, wherein the information unit (12) is a display.

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