Battery control device

Abstract

The present invention is a battery control device, which includes a battery module and a battery controller. Among them, the battery controller includes: a memory; and a control circuit that executes a program recorded in the memory to control the operation of the battery of the battery module. The memory stores battery data, which includes the relationship between the DC resistance component and the state of charge, and the relationship between the polarization resistance component and the state of charge. The control circuit calculates the degradation state of the battery, and refers to the battery data, and based on the currently calculated degradation state of the battery, extracts the relationship between the DC resistance component and the state of charge, and the relationship between the polarization resistance component and the state of charge, to control the battery.

Description

Technical Field

[0001] The present invention relates to a battery control device having a plurality of batteries built therein, such as a power storage device for a moving body, a power storage device for stabilizing system interconnection, and an emergency power storage device. Background Art

[0002] In order to exhibit the performance of the battery control device, it is necessary to appropriately determine the state of charge (SOC) of the battery, the state of deterioration (SOH) of the battery, the maximum current that can be charged and discharged (permissible current value), and the like. In order for the battery control device to calculate the maximum current, it is necessary to know the internal state and parameters of the battery, such as the open circuit voltage (OCV) and internal resistance of the battery. In particular, in a moving body that always has irregular current flowing through it and a power storage device for stabilizing system interconnection, not only is the influence of the internal resistance (DC resistance) that causes a voltage change at the moment when current flows through the battery large, but the influence of the internal resistance (polarization resistance) that causes a voltage change when current continuously flows is also large.

[0003] Parameters such as DC resistance and polarization resistance change according to the SOC and temperature of the battery. Therefore, the battery controller stores, as a data table of what values the parameters such as DC resistance and polarization resistance become at various SOCs and temperatures, or a function thereof. Then, the battery controller estimates the SOC based on the information sent from the single cell controller, and on this basis, determines the values of the parameters according to the data table or function.

[0004] However, since these parameters are determined in the initial state of the battery, if the battery deteriorates, values of parameters different from the actual values will be output from the data table or function, and the SOC, battery voltage value, permissible current value, etc. cannot be calculated correctly.

[0005] In order to correct the influence caused by the deterioration of the battery, the battery controller determines a resistance increase rate according to the SOH of the battery, and multiplies the DC resistance and polarization resistance in the initial state of the battery by the resistance increase rate to determine the DC resistance and polarization resistance after deterioration. In a battery module or battery pack formed by connecting a plurality of single cells in series or parallel, the SOH of all the single cells is determined, and the resistance increase rate of the single cell with the most severe deterioration is used to calculate the permissible current value of the battery module or battery pack.

[0006] There has been proposed to update the data table of the DC resistance component and the polarization resistance component in accordance with the deterioration of the battery. For example, Patent Document 1 discloses a learning-type algorithm for a deterioration management system that stores a data table of the DC resistance and diffusion coefficient in the initial state. On the other hand, based on the measured value of the battery voltage waveform during charge and discharge and the values of the DC resistance and diffusion coefficient determined by calculation based on a prescribed battery model, the data table of the part corresponding to the measured SOC and temperature is updated.

[0007] Prior art documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Laid-Open No. 2013-44598 Summary of the invention

[0010] Problems to be solved by the invention

[0011] In the case of battery deterioration, the DC resistance and polarization resistance do not always increase at all SOCs. At a certain SOC, the DC resistance or polarization resistance may sometimes decrease as the battery deteriorates. The DC resistance and polarization resistance of the battery originate from the DC resistance and polarization resistance of the positive electrode and the negative electrode that make up the battery. The DC resistance or polarization resistance of the positive electrode and the negative electrode has a dependence on the SOC of the positive electrode and the negative electrode respectively, and the SOC dependence of the DC resistance or polarization resistance of the battery is determined by the correspondence relationship between the SOCs of the positive electrode and the negative electrode.

[0012] On the other hand, the correspondence relationship between the SOCs of the positive electrode and the negative electrode changes as the battery deteriorates. As a result, the SOC dependence of the DC resistance or polarization resistance of the battery changes, and the DC resistance or polarization resistance decreases due to deterioration depending on the SOC. Therefore, if the allowable current value is determined corresponding to the single cell with the most severe deterioration, the allowable current of the single cell with less severe deterioration may sometimes be exceeded, and the deterioration of the single cell is accelerated.

[0013] An object of the present invention is to provide a battery control device that can prevent the current and voltage from deviating from a specified range for all single cells and suppress battery deterioration even when a plurality of single cells with different degrees of deterioration are connected in series.

[0014] Means for solving the problems

[0015] In order to achieve the above object, the present invention is a battery control device, which includes a battery module and a battery controller. The battery controller includes: a memory; and a control circuit that executes a program recorded in the memory to control the operation of the battery of the battery module. The memory stores battery data, which includes the relationship between the DC resistance component and the state of charge and the relationship between the polarization resistance component and the state of charge. The control circuit calculates the deterioration state of the battery, refers to the battery data, and extracts the relationship between the DC resistance component and the state of charge and the relationship between the polarization resistance component and the state of charge based on the calculated current deterioration state of the battery to control the battery.

[0016] Advantages of the invention

[0017] The present invention can provide a battery control device that can prevent the current and voltage from deviating from a specified range for all individual cells and suppress battery degradation even when a plurality of individual cells with different degrees of degradation are connected in series. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 FIG. 1 is an example of a hardware block diagram of a battery system according to an embodiment of the present invention for an electric vehicle or the like.

[0019] Figure 2 FIG. 2 is an example of a functional block diagram of a battery controller.

[0020] Figure 3A FIG. 3 is a graph showing an example of the voltage behavior of a battery when a rectangular wave current is applied to the battery, showing the rectangular wave current I applied to the battery.

[0021] Figure 3B FIG. 4 is a graph showing an example of the voltage behavior of a battery when a rectangular wave current is applied to the battery, showing the voltage V of the battery.

[0022] Figure 4 FIG. 5 is a diagram showing an example of an equivalent circuit model of a battery.

[0023] Figure 5 FIG. 6 is a diagram showing an example of a battery data sheet.

[0024] Figure 6A FIG. 7 is a graph showing the SOC dependence of the DC resistance R0 of a battery at a temperature of 25°C, a current of 1C, an SOH of 100%, and an SOC of 83%.

[0025] Figure 6B FIG. 8 is a graph showing the SOC dependence of the polarization resistance Rp of a battery at a temperature of 25°C, a current of 1C, an SOH of 100%, and an SOC of 83%. FIGS. 8(A) and 8(B) are graphs showing the SOC dependence of the DC resistance R0 and the polarization resistance Rp of a battery for a plurality of SOHs. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] Embodiments of the present invention will be described with reference to the accompanying drawings. Figure 1 FIG. 1 is an example of a hardware block diagram of a battery system 100 for an electric vehicle or the like. The battery system 100 includes a battery control device 1, an inverter 2, a load 3 such as a motor, and a superior controller 4.

[0027] Since the output voltage of the battery control device 1 is a DC voltage that varies according to the remaining capacity, output current, etc. of the battery, it may not be suitable for directly supplying power to the load 3. Therefore, the output voltage of the battery control device 1 is converted into three-phase alternating current by the inverter 2 and then supplied to the load 3.

[0028] The upper - level controller 4 controls the battery control device 1 and the inverter 2. In the case of supplying DC voltage, other poly - phase AC, or single - phase AC to the load 3, the battery control device 1 is also configured in the same way.

[0029] When the load 3 outputs power, by setting the inverter 2 as a bidirectional inverter, the power output from the load 3 can be stored in the battery module 11 inside the battery control device 1. By connecting a charging system in parallel with the inverter 2, the battery module 11 can be charged as needed.

[0030] The battery control device 1 sends information related to the state of the battery, such as the charge rate (SOC), the degradation rate (SOH), the maximum charge - discharge current that can flow through the battery (permissible current value), the battery temperature, and the presence or absence of battery abnormalities, which is useful for controlling the inverter 2 and the load 3, to the upper - level controller 4. The upper - level controller 4 performs energy management, abnormality detection, etc. based on this information. When the upper - level controller 4 determines that the battery control device 1 should be disconnected from the inverter 2 or the load 3, it sends a disconnection instruction to the battery control device 1.

[0031] The battery control device 1 includes: a battery module 11; a battery controller 12 that performs control such as monitoring and estimating the state of the battery; a relay 13 that makes the output of the battery control device 1 intermittent; a current sensor 14 that measures the current flowing through the battery module 11; a voltage sensor 15 that measures the voltage of the battery module 11; a leakage sensor 16 that measures the insulation resistance between the battery control device 1 and the ground wire; a temperature sensor 17 that measures the battery temperature; and a circuit breaker 18 that is turned on and off according to the output voltage of the battery control device 1. The battery control device 1 includes a plurality (two) of battery modules 11 connected in series via the circuit breaker 18.

[0032] The battery controller 12 includes a CPU (control circuit) 121 that performs various operations and a storage unit (memory) 122 that stores a data table (data structure) described later.

[0033] The battery module 11 has a plurality of unit cells (single cells), and includes a circuit that measures the temperature inside the battery module 11, a circuit that measures the voltage of the unit cells, and a circuit that performs charge - discharge of each unit cell as needed. Therefore, voltage monitoring and voltage adjustment of each unit cell can be performed. The battery controller 12 can estimate, determine, or judge the state of the battery based on the temperature information of the unit cells.

[0034] A plurality of battery modules 11 are connected in series, and the current sensor 14 is connected in series with a pair of relays 13. The current sensor 14 measures the current value required for the battery controller 12 to monitor and estimate the state of the battery module 11.

[0035] The battery controller 12 can cut off or connect the output of the battery control device 1 by controlling the opening and closing of a pair of relays 13 based on the instructions from the superior controller 4.

[0036] To prevent the battery module 11 from becoming a high voltage (e.g., 100V), a switch for forcibly cutting off the power input / output to the battery control device 1 manually can also be added in series with the relay 13. Thus, during the assembly or disassembly of the battery control device 1, or in response to an accident of the device loaded with the battery control device 1, short circuits can be prevented, for example.

[0037] For a structure in which multiple battery modules 11 are connected in parallel, relays 13, switches, and current sensors 14 can also be provided in each column. Or, relays 13, switches, and current sensors 14 can be provided only at the output part of the battery control device 1. Furthermore, relays 13, switches, and current sensors 14 can be provided in both each column and the output part of the battery control device 1.

[0038] The relay 13 can be composed of one unit, or can be composed of a group of a main relay, a pre-charge relay, and a resistor. In the latter structure, a resistor is arranged in series with the pre-charge relay, and they are connected in parallel with the main relay.

[0039] When the battery controller 12 connects the relay 13, the pre-charge relay is connected first. Since the current flowing through the pre-charge relay is limited by the serially connected resistor, the inrush current that may occur in the former structure can be limited. Then, after the current flowing through the pre-charge relay becomes small enough, the main relay is connected. The moment when the main relay is connected can be based on the current flowing through the pre-charge relay, or can be based on the voltage applied to the resistor or the voltage between the terminals of the main relay. Or, the time elapsed since the pre-charge relay was connected can be used as a reference.

[0040] The voltage sensor 15 measures the voltage value required for the battery controller 12 to monitor and estimate the state of the battery module 11. The voltage sensor 15 is connected in parallel with one or more battery modules 11.

[0041] A leakage sensor 16 is connected to the battery module 11 to detect a state where leakage may occur before leakage actually occurs, that is, a state where the insulation resistance decreases, to prevent accidents.

[0042] The current sensor 14, voltage sensor 15, temperature sensor 17, and leakage current sensor 16 respectively send the measured values to the battery controller 12. Based on the received measured values, the battery controller 12 monitors and estimates the battery state of the battery module 11, and as a result, the battery module can be controlled. "Control" includes, for example, charge and discharge of each unit cell for equalizing the voltage of each unit cell, control of the power supply of each sensor, addressing of each sensor, control of the relay 13 connected to the battery controller 12, etc. The CPU 121 performs operations required for monitoring, estimating, and the above control of the battery state.

[0043] The battery control device 1 may also include a fan for system cooling, and its control is sometimes performed by the battery controller 12. By cooling through the battery control device 1, the communication volume with the upper controller 4 can be reduced.

[0044] In Figure 1 In the example shown, by making the voltage sensor 15 and the leakage current sensor 16 different components from the battery controller 12, there is freedom, but it can also be configured such that the voltage sensor 15 and the leakage current sensor 16 are built into the battery controller 12. Thereby, compared with the case of preparing separate sensors, the number of wire harnesses can be reduced, and the workload of sensor installation can be reduced. However, sometimes the scale (maximum output voltage, current, etc.) of the battery control device 1 that can be dealt with by the built-in sensors is limited, so in such cases, it is preferably set as other components.

[0045] Figure 2 This is an example of the functional block diagram of the battery controller 12. The CPU 121 realizes the degradation state estimation unit 1201, charge state estimation unit 1202, and allowable current calculation unit 1204 as functional components by executing the program recorded in the storage unit 122. The "unit" can also be referred to as a function, means, component, unit, unit, circuit, step, etc. The functional components can also be realized by hardware such as a semiconductor circuit. The storage unit 122 includes a battery data table 1205.

[0046] The degradation state estimation unit 1201 and the charge state estimation unit 1202 respectively input the values of current, voltage, and temperature from a sensor group such as a current sensor, voltage sensor, and temperature sensor. The degradation state estimation unit 1201 estimates the degradation state of the battery based on the current I, voltage V, and temperature T. The "estimation" can also be referred to as setting, determination, judgment, or discrimination. The same applies to the charge state estimation unit 1202.

[0047] The degradation state estimation unit 1201 can, for example, adopt a reduction in the capacity of the battery as an index indicating the degradation state of the battery. As a method for estimating the reduction in the capacity of the battery, for example, there are the following methods.

[0048] The degradation state estimation unit 1201 integrates the charge-discharge amount Q_AB from time point A to another time point B. Then, it calculates OCV_A at time point A and OCV_B at time point B, and referring to the battery data table in the initial state, obtains the charge-discharge amount Q_AB corresponding to OCV_A and the charge-discharge amount Q'_AB corresponding to OCV_B. On this basis, Q'_AB / Q_AB is used as the capacity reduction rate. This capacity reduction rate is set as SOH.

[0049] The charge state estimation unit 1202 estimates the charge state of the battery based on the current I, voltage V, temperature T, and the equivalent circuit model of the battery (single cell). FIG. 3 is a diagram showing an example of the voltage behavior of the battery when a rectangular wave current is applied to the battery. Figure 4 is an example of the equivalent circuit model of the battery. Figure 3A represents the rectangular wave current I applied to the battery, Figure 3B represents the voltage V of the battery. The horizontal axis is the elapsed time in both cases.

[0050] When, for example, Figure 3A a rectangular wave current I as shown by curve 31 is applied to the battery, the voltage V of the battery, that is, the CCV (closed-circuit voltage) of the battery, changes as Figure 3B shown by curve 32. The change in this voltage is roughly divided into three components: a DC voltage component I×R0, a polarization voltage component Vp, and an OCV variation component ΔOCV. R0 is the DC resistance component.

[0051] As the first component, the DC voltage component I×R0 responds instantaneously to the change in the current I. That is, it instantaneously rises corresponding to the rising edge of the current I, and after changing at a certain level, it disappears together with the falling edge of the current I.

[0052] As the second component, the polarization voltage component Vp changes with a delay with respect to the change in the current I. That is, it gradually rises after the rising edge of the current I and gradually falls after the falling edge of the current I.

[0053] As the third component, ΔOCV is equivalent to the difference between OCV1, which is the OCV value before the start of charging, and OCV2, which is the OCV value after the start of charging. ΔOCV corresponds to the change amount of the charge state of the battery corresponding to the charge-discharge amount.

[0054] In Figure 4 , the DC voltage component is obtained by applying the current I to the DC resistance component R0. Rp represents the polarization resistance component, Cp represents the polarization capacitance component, and based on these values, the current I, and the charge-discharge time t, the polarization voltage component Vp is obtained. The polarization voltage component Vp represents an exponential function change based on the time constant RpCp.

[0055] As a first method, the charge state estimation unit 1202 calculates the SOC by referring to a battery data table described later that represents the relationship between the SOC and the OCV of the battery, based on the OCV of the battery obtained by analyzing the CCV of the battery using an equivalent circuit model. As a second method, the SOC can also be calculated based on the charge and discharge power ΔQ obtained by integrating the current I, according to the relationship between ΔQ and the SOC. The two methods can also be combined to calculate the SOC.

[0056] Figure 5 is an example of the battery data table 1205. The items in the table include SOH (%), temperature T (°C), SOC (%), current I (A), OCV (V), DC resistance Ro (Ω), polarization resistance Rp (Ω), and polarization capacitance Cp (F) (or polarization time constant τp (s)). Instead of the battery data table, it can also be a function representing the data.

[0057] The battery data table 1205 includes the respective DC resistances Ro (Ω), polarization resistances Rp (Ω), and polarization capacitances Cp (F) for the temperature T, SOC, SOH, and current I within a specified range, respectively, for their specified combinations. That is, in the battery data table, for each of a plurality of combinations where the battery capacity reduction rate (SOH), battery temperature (T), battery charge rate (SOC), and battery current (I) are respectively specified values, the values of the battery DC resistance Ro (Ω), polarization resistance Rp (Ω), and polarization capacitance Cp (F) are set. In Figure 5 represents the case where the SOH is at the N level, the SOC is at the M level, the temperature is at the L level, and the current is at the K level. The number of combinations of OCV, DC resistance, polarization resistance, and polarization capacitance is N × M × L × K.

[0058] Figure 5 The battery data table is determined in advance through experiments and simulations. For example, a single cell with an SOH at any level in the M level (e.g., SOH_1) in a battery pack is connected to a charge and discharge device in a thermostat set at any temperature in the L level (e.g., T_1). After adjusting the SOC to any level in the N level (e.g., SOC_1), the current is set to any level in the K level (e.g., I_1) and charged or discharged for a certain period of time. The behavior of the obtained CCV is analyzed to determine the DC resistance Ro, polarization resistance Rp, and polarization capacitance Cp. Thus, the Ro, polarization resistance Rp, and polarization capacitance Cp corresponding to SOH_1, T_1, SOC_1, and I_1 can be determined. By performing this process for the M × N × L × K combinations of levels, the Figure 5 battery data table can be realized. The battery data table does not need to be set for each individual single cell, and only one battery table needs to be set for each specification of the single cell (by manufacturer, by model, by type, etc.).

[0059] It is also possible to replace part or all of the data table with a function. For example, regarding the temperature dependence of Rp, it is also possible to approximate part of the data table by setting A and B as appropriate constants and using an exponential function such as Rp = A × exp(B / (T + 273)). Regarding SOH, SOC, and current, as long as the tendency of the experimental data can be approximated by an appropriate function, part of the data table can be replaced in the same way.

[0060] Figure 6A It is a graph showing the SOC dependence of the DC resistance R0 of a battery at a temperature of 25°C, a current of 1C, an SOH of 100%, and 83%. Figure 6B It is a graph showing the SOC dependence of the polarization resistance Rp of a battery at a temperature of 25°C, a current of 1C, an SOH of 100%, and 83%. The current of 1C refers to the current value that discharges the total capacity of the battery within 1 hour.

[0061] The allowable current calculation unit 1204 is allowed to calculate the allowable current of the battery with reference to the DC resistance, polarization resistance, and polarization capacity of the battery stored in the battery data table 1205 according to the current temperature, SOC, and SOH of the battery. As part of the safety function to prevent overvoltage of the battery, the allowable current calculation unit 1204 restricts the current so as not to exceed the allowable current value, thereby suppressing the rapid deterioration of the battery while maintaining the safety of the battery control device 1. Regarding the allowable current used for this, an example of the calculation for obtaining the allowable current is shown below.

[0062] I cmax = (V max - OCV) / R ··· (Equation 1)

[0063] Icmax is the charging allowable current, Vmax is the upper limit voltage, and R is the internal resistance of the battery.

[0064] The discharge allowable current is calculated using the following equation (2).

[0065] I dmax = (OCV - V min) / R ··· (Equation 2)

[0066] Idmax is the discharge allowable current, Vmin is the lower limit voltage, and R is the internal resistance of the battery.

[0067] R is calculated using the following equation (3), for example.

[0068] R = Ro + Rp(1 - e -t / RpCp ) ··· (Equation 3)

[0069] Ro, Rp, and Cp are obtained from the battery data table 1205. t is the time (seconds). To select Ro, Rp, and Cp from the database, the current needs to be specified. Therefore, for example, there is a method of simply calculating the allowable current using Ro, Rp, and Cp under a specified current. Additionally, for example, there is also a method of repeatedly extracting Ro, Rp, and Cp and calculating the equations (1) to (3) while changing the specified current, and exploring the allowable current for which the equations (1) to (3) hold without contradiction.

[0070] The allowable current calculation unit 1204 calculates the allowable input and allowable output of the battery based on the DC resistance, polarization resistance, and polarization capacitance of the battery stored in the battery data table 1205.

[0071] The allowable input is calculated according to the following equation (4).

[0072] I cmax*V max ··· (Equation 4)

[0073] The allowable output is calculated by the following equation (5).

[0074] I dmax*V min ··· (Equation 5)

[0075] Next, the operation of the battery control device will be described. In the initial state of the battery, in the Figure 5 shown battery data table, the DC resistance component, polarization resistance component, and polarization capacitance component of the battery correspond to temperature, SOC, SOH, and current respectively.

[0076] After that, the battery is used starting from the initial state of the battery. For example, when the engine is started, when the battery is charged based on an external power source, or during a regular inspection, the degradation state estimation unit 1201 updates the current SOH of the battery. Thereafter, the equivalent circuit parameter table corresponding to the updated SOH is used.

[0077] The charge state estimation unit 1202 calculates the SOC based on the charge and discharge power ΔQ obtained by integrating the current I detected by the current sensor 14, based on the relationship between the charge and discharge power and the SOC. Or, based on the OCV of the battery obtained during rest and the relationship between the SOC and the OCV, the SOC is calculated. Or, the OCV, DC resistance, polarization resistance, or polarization capacitance obtained by analyzing the detection values of the current sensor 14 and the voltage sensor 15 using an equivalent circuit model is used to calculate the SOC. Or, a combination of multiple of these calculation methods is used to calculate the SOC.

[0078] Next, the allowable current calculation unit 1204 calculates the allowable charge current and allowable discharge current of the battery using equations (1) to (3) based on the DC resistance, polarization resistance, and polarization capacitance of the battery stored in the battery data table 1205. In addition, the allowable input Iin and allowable output Iout are calculated using equations (4) and (5).

[0079] The allowable current calculation unit 1204 performs the above calculations of the allowable current and allowable input / output for all the single cells constituting the battery module (battery pack). At this time, since the temperature, SOC, and SOH of each single cell are different, the allowable current and allowable input / output of each single cell are different. The allowable current calculation unit 1204 selects the current with the smallest absolute value among the allowable currents of a series-connected group of single cells in the battery module (battery pack) as the allowable current of the series-connected single cell group.

[0080] According to the embodiment described above, the following effects can be obtained. The battery control device (1) includes a degradation state estimation unit (1201) that estimates the current degradation state of the battery from a battery data table including the relationship between the DC resistance component and the charge state and the relationship between the polarization resistance component and the charge state for multiple batteries in different degradation states, and based on the current degradation state of the battery estimated by the degradation state estimation unit (1201), extracts parameters including the DC resistance component and the polarization resistance component of the battery at the current time from the battery data table including the relationship between the DC resistance component and the charge state and the relationship between the polarization resistance component and the charge state, and calculates the allowable current of the single cell based on these parameters.

[0081] The minimum value of the allowable currents of the single cells constituting the series group is set as the allowable current of the entire series group. Thus, in the case where single cells with different degrees of degradation are connected in series, it is possible to prevent the current and voltage from deviating from the specified range for all the single cells, and suppress battery degradation.

[0082] In addition, in the embodiment where the battery module has a structure in which a plurality of groups formed by connecting a plurality of single cells in series are connected in parallel, the allowable current calculation unit 1204 sets the allowable current for each of the plurality of groups, and sets the sum of the allowable currents of each group as the allowable current of the battery module.

[0083] The present invention is not limited to the above-described embodiment, and other embodiments considered within the technical idea of the present invention are also included in the scope of the present invention as long as the features of the present invention are not impaired.

[0084] Description of reference symbols

[0085] 1 Battery control device

[0086] 2 Inverter

[0087] 3 Load

[0088] 4 Superior controller

[0089] 11 Battery module

[0090] 12 Battery controller

[0091] 13 Relay

[0092] 14 Current sensor

[0093] 15 Voltage sensor

[0094] 16 Leakage sensor

[0095] 17 Temperature sensor

[0096] 18 Circuit breaker

[0097] 100 Battery system

[0098] 121 CPU

[0099] 122 Storage unit

Claims

1. A battery control device including a battery module and a battery controller, characterized in that, the battery module includes a plurality of batteries, the battery controller includes: a memory; and a control circuit that executes a program recorded in the memory to control the operation of each battery in the battery module, the memory stores battery data, and this battery data contains the correspondence relationship of the deterioration state, charge state, DC resistance component, and polarization resistance component of the battery, the control circuit, estimates the deterioration state of each battery, refers to the battery data, and based on the currently estimated deterioration state of the battery, extracts the relationship between the DC resistance component and the charge state and the relationship between the polarization resistance component and the charge state to determine the allowable current of each battery, uses the allowable current with the smallest absolute value among the determined allowable currents as the allowable current of each battery, the battery control device includes: a current sensor for measuring the current (I) of the battery module; a voltage sensor for measuring the voltage (V) of the battery module; and a temperature sensor for measuring the temperature (T) of each battery in the battery module, the control circuit calculates the reduction rate of the capacity of each battery based on the current (I), voltage (V), and temperature (T), and estimates the deterioration state of the battery based on the calculated reduction rate of the capacity of the battery.

2. The battery control device according to claim 1, characterized in that: the control circuit estimates the charge state of the battery based on the current (I), voltage (V), temperature (T), and the equivalent circuit model of the battery.

3. The battery control device according to claim 2, characterized in that: in the memory, a battery data table is stored as the battery data, the items of this battery data table include the battery capacity reduction rate (SOH), battery temperature (T), battery charge rate (SOC), battery current (I), battery DC resistance (Ro), battery polarization resistance (Rp), and battery polarization capacity (Cp).

4. The battery control device according to claim 3, characterized in that: in the battery data table, for each of a plurality of combinations in which the battery capacity reduction rate (SOH), the battery temperature (T), the battery charge rate (SOC), and the battery current (I) are respectively specified values, the values of the battery DC resistance (Ro), the battery polarization resistance (Rp), and the battery polarization capacity (Cp) are set respectively.

5. The battery control device according to claim 4, characterized in that: the control circuit calculates the allowable current of each battery based on the current battery capacity reduction rate (SOH), battery temperature (T), and battery charge rate (SOC), and refers to the battery DC resistance (Ro), battery polarization resistance (Rp), and battery polarization capacity (Cp) stored in the battery data table.

6. The battery control device according to claim 5, characterized in that: the plurality of batteries are connected in series.

7. The battery control device according to claim 5, characterized in that: The battery module has a structure formed by connecting multiple groups in parallel, where each group is formed by connecting multiple single cells in series. The control circuit sets an allowable current for each of the multiple groups, and sets the sum of the allowable currents of each group as the allowable current of the battery module.

Images