Battery control device and battery control method

Abstract

This battery control device comprises a controller 10 that estimates the deterioration levels of a plurality of high-power components 1-3 which are connected to a battery, and controls the power which is inputted / outputted from the battery 4 to the plurality of high-power components 1-3. The controller 10 estimates the deterioration level of each of the plurality of high-power components 1-3 on the basis of at least one factor among the integrated value of the current flowing from the battery 4 to the high-power component 1-3, the use time of the high-power component, and the number of times the high-power component 1-3 is used, calculates the current and / or temperature tolerance for each of the plurality of high-power components 1-3 on the basis of the estimated deterioration level thereof, sets the maximum power of the battery 4 on the basis of the lowest tolerance among the plurality of tolerances respectively calculated for the plurality of high-power components 1-3, and controls the input power or the output power of the battery 4 to be less than or equal to the maximum power.

Description

Battery control device and battery control method

[0001] The present invention relates to a battery control device and a battery control method.

[0002] Conventionally, in vehicles equipped with fuses, an ECU sets a baseline, which is a target deterioration level of the fuse, according to the cumulative mileage of the vehicle, and when the fuse deterioration level estimated from the fuse temperature history exceeds the baseline set according to the cumulative mileage, the vehicle gradually reduces the input / output power of the battery from a normal value to a limited value (Patent Document 1).

[0003] JP 2016-158463 A

[0004] However, since a vehicle has multiple high-voltage components other than fuses, and the tolerances of the multiple high-voltage components vary depending on the degree of deterioration of each component, the method described in Patent Document 1, which gradually reduces the input / output power of the battery based solely on the degree of deterioration of the fuse, has the problem that it is not possible to control the input / output power of the battery in accordance with the tolerances of high-voltage components other than the fuse.

[0005] The problem to be solved by the present invention is to provide a battery control device and a battery control method that can control the input power or output power of a battery according to the withstand capacities of a plurality of high-voltage components.

[0006] The present invention solves the above problem by estimating the degree of deterioration of each of a plurality of high-voltage components based on at least one of the following elements: the accumulated current value of the current flowing from the battery to the high-voltage component, the usage time of the high-voltage component, and the number of times the high-voltage component has been used; calculating the current and / or temperature tolerance for each of the plurality of high-voltage components based on the estimated degree of deterioration; setting an upper limit power for the battery based on the lowest tolerance among the plurality of tolerances calculated for each of the plurality of high-voltage components; and controlling the input power or output power of the battery to be below the upper limit power.

[0007] According to the present invention, the input power or output power of the battery can be controlled in accordance with the withstand voltages of a plurality of high-voltage components.

[0008] Fig. 1 is a block diagram of a battery control system according to an embodiment of the present invention, Fig. 2 is a graph showing IT characteristics of a plurality of high-voltage components, and Fig. 3 is a flowchart showing steps of a battery control method according to an embodiment of the present invention.

[0009] A battery control device and a battery control method according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a battery control system 100. The battery control system 100 is mounted on a vehicle and controls the input power or output power of a battery according to the withstand capacity of a high-power load including the battery. The battery control system 100 includes a high-power component 1, a high-power component 2, a high-power component 3, a battery 4, and a controller 10. The device including the controller 10 corresponds to the battery control device of the present invention.

[0010] High-voltage components 1 to 3 are components that operate using power from battery 4, or components connected to the conduction path of the input / output current of battery 4, or wiring that conducts the current of battery 4, and are high-voltage components that handle high voltage. High-voltage components 1 to 3 are connected to battery 4. High-voltage component 1 is, for example, a relay, high-voltage component 2 is a harness, and high-voltage component 3 is, for example, a fuse. Note that relays, harnesses, and fuses are examples of high-voltage components 1 to 3, and high-voltage components 1 to 3 may also be other components. Note that auxiliary devices such as displays and lamps are not included in high-voltage components 1 to 3 and are considered low-voltage components.

[0011] The battery 4 is connected to a load by a high-voltage component (high-voltage harness) 2 via a high-voltage component 1 (relay) and a high-voltage component (fuse) 3, and includes a plurality of secondary batteries such as lead batteries or lithium-ion batteries. If the vehicle is, for example, a hybrid vehicle or an electric vehicle, the battery 4 is connected to the motor via an inverter as a drive battery. During regeneration of the motor, the battery 4 is charged with regenerated energy. If the vehicle has an engine for generating electricity, the battery may be charged with power generated by the engine. The battery 4 is one of the components included in the high-voltage components.

[0012] The controller 10 estimates the degree of deterioration of the plurality of high-voltage components 1 to 3 and the battery 4, and controls the power input to or output from the battery 4 to the plurality of high-voltage components 1 to 3. The controller 10 is configured as a computer equipped with hardware and software, and includes a memory storing programs and a CPU for executing the programs stored in the memory. The controller 10 has functions such as estimating the degree of deterioration of the plurality of high-voltage components 1 to 3 and the battery 4, calculating the tolerances of the plurality of high-voltage components 1 to 3 and the battery 4, and controlling the input / output power of the battery 4. The controller 10 has functional blocks corresponding to each function, including a deterioration degree estimation unit 11, a tolerance calculation unit 12, and a battery input / output control unit 13. In the following description, the input / output power of the battery 4 is used as a general term for the input power and output power of the battery 4, and refers to at least one of the input power and the output power of the battery 4.

[0013] The deterioration level estimation unit 11 estimates the deterioration levels of the high-voltage components 1-3 and the battery 4 based on at least one of the following: an integrated current value of the current flowing from the battery 4 to the high-voltage components 1-3; the usage time of the high-voltage components 1-3 or the battery 4; and the number of times the high-voltage components 1-3 or the battery 4 have been used. The integrated current value is an integrated value of the charging / discharging current that has flowed through the high-voltage components 1-3 to date. The controller 10 acquires detection values ​​from current sensors electrically connected to the battery 4 and / or the high-voltage components 1-3 and calculates the integrated current value by integrating the detection values. The usage time corresponds to, for example, the elapsed time from the time the vehicle was shipped to the present, the integrated value of the on-time of the high-voltage component (relay) 1, the integrated value of the time current was input or output from the battery 4, etc. For example, when calculating the elapsed time from the time the vehicle was collected to the present as the usage time, the controller 10 may store information about the vehicle's shipping date in a memory or the like in advance, and calculate the elapsed time (number of days) from the shipping date to the present as the usage time. The number of uses is the number of times the high voltage component (relay) 1 is switched on and off, the charge / discharge cycles of the battery 4, the number of times the vehicle is started, etc. The number of times the vehicle is started corresponds to, for example, the number of times the main switch (power switch, ignition switch) of the vehicle is switched from off to on.

[0014] The deterioration level estimation unit 11 estimates the deterioration levels of the plurality of high-voltage components 1 to 3 and the battery 4 so that the deterioration level increases as the current integrated value increases, the usage time increases, or the number of times the components are used increases. The deterioration level does not need to be a value that changes continuously according to the current integrated value or the like, but may be a value that changes stepwise according to the current integrated value or the like. The deterioration level estimation unit may also estimate the deterioration levels of the plurality of high-voltage components 1 to 3 and the battery 4 based on a plurality of elements among the current integrated value, usage time, the high-voltage components 1 to 3, and the number of times the components are used. The deterioration level estimation unit 11 may estimate the deterioration level (SOH) of the battery 4 by comparing the current full charge capacity of the battery 4 with the full charge capacity of the battery 4 in an initial state. The deterioration level estimation unit 11 estimates the deterioration levels (α １ ~α ３ ) and the deterioration degree of the battery 4 (α ４ ) is estimated. １ ) indicates the degree of deterioration of the high-voltage component 1, and the degree of deterioration (α ２ ) indicates the degree of deterioration of the high-voltage component 3, and the degree of deterioration (α ３ ) indicates the degree of deterioration of the high-voltage component 3.

[0015] The deterioration level estimation unit 11 may estimate the deterioration levels of the multiple high-voltage components 1 to 3 based on the SOH of the battery 4. For high-voltage components 1 to 3 whose deterioration levels correspond to the SOH of the battery 4, the deterioration level estimation unit 11 may estimate the SOH of the battery 4 as the deterioration level of the high-voltage components 1 to 3 in order to simplify the calculation process of the deterioration levels. Alternatively, the controller 10 may calculate in advance the correlation between the SOH of the battery 4 and the deterioration levels of the high-voltage components 1 to 3 from experimental data or the like, and store data indicating the correlation in memory. The deterioration level estimation unit 11 may then refer to the data indicating the correlation between the SOH of the battery 4 and the deterioration levels of the high-voltage components 1 to 3, and estimate the deterioration levels corresponding to the current SOH of the battery 4 as the current deterioration levels of the high-voltage components 1 to 3. This reduces the calculation load on the controller 10.

[0016] The tolerance calculation unit 12 calculates the current and / or temperature tolerance of each of the high-voltage components 1 to 3 for each of the multiple high-voltage components based on the degree of degradation estimated by the degradation degree estimation unit 11. The high-voltage components 1 to 3 have a specified tolerance based on the current and / or temperature, and the tolerance differs depending on the component. The tolerance is indicated by the upper limit of the current that can be passed through the high-voltage components 1 to 3. The tolerance is also indicated by the upper limit of the temperature that can be applied to the high-voltage components 1 to 3. In other words, the tolerance of the high-voltage components 1 to 3 is the allowable value of the load that can be applied to the high-voltage component 1. The load that can be applied to the high-voltage component 1 is indicated by the current and / or temperature.

[0017] 2 is a graph showing the characteristics (IT characteristics) of the current tolerance of the high voltage components 1 to 3. In FIG. 2, the vertical axis represents time, and the vertical axis represents the current value flowing through the high voltage components 1 to 3. Graph β １ is the withstand capacity of high-voltage component 1 (β １ The current tolerance of the high-voltage components 1 to 3 is a value according to the time-current characteristics (IT characteristics) of each of the high-voltage components 1 to 3, and the time-current characteristics (IT characteristics) indicate the time until the load on the high-voltage components 1 to 3 reaches its upper limit when a current of a predetermined magnitude is continuously passed through the high-voltage components 1 to 3.

[0018] 2, the withstand voltages of the high voltage components 1 to 3 are different for each of the high voltage components 1 to 3. In other words, the time domain and upper limit current domain that define the withstand voltages of the high voltage components 1 to 3 are different values ​​for each of the high voltage components 1 to 3.

[0019] The current tolerance of the high-voltage components 1 to 3 decreases as the degree of deterioration of the high-voltage components 1 to 3 increases. ３ ) indicates the withstand voltage of the high voltage component 3 in the initial state (Beginning of Life), and the graph (β ３ The graph (β ′) in FIG. 2 shows the withstand voltage of the high-voltage component 3 after degradation (End of Life). ３ , β ３ As shown in Figure 2', when high-voltage component 3 deteriorates, the withstand voltage of high-voltage component 3 decreases. Note that while Figure 2 shows the characteristics of the withstand voltage before and after deterioration of high-voltage component 3, the withstand voltages of high-voltage components 1 and 2 also decrease when high-voltage components 1 and 2 deteriorate.

[0020] The controller 10 stores in memory the tolerance data indicating the tolerance of the amount of current of the high-voltage components 1 to 3 as shown in FIG. 2 in association with the degree of deterioration of the high-voltage components 1 to 3. The tolerance calculation unit 12 refers to the tolerance data stored in the memory and calculates the estimated degree of deterioration (α １ ~α ３ ) corresponding to the tolerance (β １ ~β ３ For example, the estimated deterioration degree (α １ ~α ３ ) is a deterioration degree corresponding to the initial state, the tolerance calculation unit 12 calculates the deterioration degree corresponding to the graph (β １ ~β ３ ) is calculated as the withstand current for each of the plurality of high voltage components 1 to 3.

[0021] The controller 10 stores in advance in a memory tolerance data indicating the temperature tolerance of the high-voltage components 1 to 3 in association with the degree of deterioration of the high-voltage components 1 to 3, and the tolerance calculation unit 12 calculates the estimated degree of deterioration (α １ ~α ３ ) corresponding to the tolerance (β １ ~β ３ The temperature resistance (withstand voltage temperature) of the high voltage components 1 to 3 may be expressed by the characteristics of the square of the current and time.

[0022] The tolerance calculation unit 12 also calculates the deterioration degree (α ４ ), the upper limit of the input / output power of the battery 4 is calculated based on the estimated degradation level (α ４ ) the upper limit of the battery input / output power (β ４ ) may be calculated. ４ ) is not limited to the power characteristic, but may be expressed by the IT characteristic as shown in FIG. ４), I of the IT characteristics corresponds to the charge / discharge current, and T corresponds to the charge / discharge time. The upper limit of the input / output power of the battery 4 may be set to a value corresponding to the temperature tolerance of the battery 4.

[0023] The tolerance calculation unit 12 calculates the upper limit temperature and the estimated degree of deterioration (α １ ~α ３ ) may be used to calculate the current tolerance. The upper temperature limit for each of the high-voltage components 1 to 3 is a predetermined upper temperature limit for ensuring normal function of the high-voltage components 1 to 3 or preventing excessive deterioration of the high-voltage components 1 to 3, and is determined, for example, depending on the materials used for the high-voltage components 1 to 3. Depending on the components used as the high-voltage components 1 to 3, some components are more likely to rise in temperature and reach their upper temperature limit when the high-voltage components 1 to 3 are highly deteriorated. The correlation between the degree of deterioration of the high-voltage components 1 to 3 and the temperature rise of the high-voltage components 1 to 3 is experimentally determined using experimental data, etc. The tolerance calculation unit 12 refers to data indicating the correlation between the degree of deterioration of the high-voltage components 1 to 3 and the temperature rise of the high-voltage components 1 to 3, and calculates the upper temperature limit for the high-voltage components 1 to 3 from the current degree of deterioration of the high-voltage components 1 to 3. For example, if the degree of deterioration of the high-voltage components 1 to 3 is high, the tolerance calculation unit 12 calculates a lower upper temperature limit for the high-voltage components 1 to 3. The tolerance calculation unit 12 then calculates the tolerance of the amount of current so that the current temperatures of the high-voltage components 1 to 3 do not exceed their upper limit temperatures. For example, the tolerance calculation unit 12 calculates the tolerance of the amount of current so that the greater the temperature difference between the current temperatures of the high-voltage components 1 to 3 and their upper limit temperatures, the greater the tolerance of the amount of current. The current temperatures of the high-voltage components 1 to 3 may be calculated from the square of the current flowing through the high-voltage components 1 to 3 multiplied by the conduction time of the current flowing through the high-voltage components 1 to 3, or may be detected by a temperature sensor. In this way, the tolerance of the amount of current of the high-voltage components 1 to 3 can be calculated according to the degree of deterioration of the high-voltage components 1 to 3 so that the temperatures of the high-voltage components 1 to 3 do not exceed their upper limit temperatures.

[0024] The battery input / output control unit 13 calculates the tolerances (β １ ~β ３) and sets the upper limit power of battery 4 based on the lowest tolerance of the above. The upper limit power of battery 4 is the upper limit value of the input power or output power of battery 4. For example, it is assumed that, among the plurality of high-voltage components 1 to 3, high-voltage components 1 and 2 have a low degree of degradation, and high-voltage component 3 has a high degree of degradation. In this state, the tolerance calculation unit 12 calculates the tolerance of high-voltage components 1 and 2 based on the degree of degradation of high-voltage components 1 and 2, as shown in the graph (β １ , β ２ ) as the withstand currents of the plurality of high-voltage components 1 and 2. The withstand current calculation unit 12 also calculates the current values ​​shown in the graph (β ３ The battery input / output control unit 13 calculates the current value indicated by the current tolerance (β １ , β ２ , β ３ ') and select the lowest tolerance (Select Low). For example, ２ ), the tolerance (β ２ ) upper limit region of the current (I ２ ) is the lowest. １ ), the tolerance (β １ ) upper limit region of the current (I １ ) is the lowest. ３ In the case of ３ The upper limit region of the current (I ３ ') is lowest. The battery input / output control unit 13 obtains the component limit line (γ) of the plurality of high-voltage components 1 to 3 by selecting the lowest tolerance for each time domain. The battery input / output control unit 13 then calculates the upper limit value of the input / output power of the battery 4 from the IT characteristics of the component limit line (γ). That is, the battery input / output control unit 13 calculates the upper limit value of the input / output power of the battery 4 so that the current tolerance of the plurality of high-voltage components 1 to 3 does not exceed the component limit line (γ). Furthermore, the battery input / output control unit 13 sets the upper limit value of the input / output power of the battery 4 as the upper limit power of the battery, and controls the input power or output power of the battery to be equal to or less than the upper limit power.

[0025] Next, the battery control method according to this embodiment will be described. Fig. 3 is a flowchart showing the steps of the battery control method. The controller 10 repeatedly executes the control flow shown in Fig. 3.

[0026] In step S1, controller 10 estimates the degree of deterioration of each of the plurality of high electric power components 1 to 3 based on at least one of the following: an integrated current value of the current flowing from battery 4 to high electric power components 1 to 3; the usage time of high electric power components 1 to 3; and the number of times high electric power components 1 to 3 have been used. In step S2, controller 10 calculates the current tolerance for each of the plurality of high electric power components 1 to 3 based on the estimated degree of deterioration. In step S3, controller 10 selects the lowest tolerance among the plurality of tolerances calculated for each of the plurality of high electric power components, and sets the upper limit of the input / output power of battery 4 to the upper limit power of battery 4 such that the current amount and / or temperature of the plurality of high electric power components 1 to 3 do not exceed the selected tolerance (corresponding to the component limit line (γ) in FIG. 2 ).

[0027] In step S4, the battery input / output control unit 13 determines whether the current input / output power of the battery 4 is equal to or greater than the upper limit power. If the current input / output power of the battery 4 is equal to or greater than the upper limit power, the battery input / output control unit 13 limits the input / output power of the battery 4 so that the current input / output power of the battery 4 is less than the upper limit power (step S5). If the current input / output power of the battery 4 is less than the upper limit power, the battery input / output control unit 13 does not limit the input / output power of the battery 4.

[0028] In the battery control device and battery control method according to the present embodiment, the controller 10 estimates the degree of deterioration of each of the high-power components 1-3 based on at least one of the following: the current integration value of the current flowing from the battery 4 to the high-power components 1-3, the usage time of the high-power components 1-3, and the number of times the high-power components 1-3 have been used; calculates the current and / or temperature tolerance for each of the high-power components 1-3 based on the estimated degree of deterioration; sets an upper limit for the power of the battery 4 based on the lowest tolerance among the multiple tolerances calculated for each of the high-power components 1-3; and controls the input or output power of the battery 4 to be equal to or less than the upper limit. This allows the input or output power of the battery to be controlled according to the tolerances of the high-power components 1-3. Furthermore, in this embodiment, the degree of deterioration is estimated based on the current integration value, the usage time of the high-power components 1-3, or the number of times the high-power components 1-3 have been used, enabling general-purpose deterioration estimation for each of the high-power components 1-3. Furthermore, the high-power components 1-3 can be effectively utilized up to their performance limits.

[0029] In this embodiment, the current tolerance is a value according to the time-current characteristics of each of the high-voltage components 1 to 3. The time-current characteristics indicate the time until the load of the high-voltage component reaches its upper limit when a constant current is continuously passed through the high-voltage component. This allows the input and output power of the battery to be controlled according to the IT characteristics of the high-voltage components 1 to 3.

[0030] In a modification of this embodiment, when the estimated deterioration level of each of the high-voltage components 1 to 3 reaches the upper-limit deterioration level set for each of the high-voltage components 1 to 3, the controller 10 notifies the user to replace the high-voltage components 1 to 3, and updates the calculation result of the withstand capacity when the high-voltage components 1 to 3 are replaced. Upper-limit deterioration levels indicating the component's usability limit are set in advance for each of the high-voltage components 1 to 3. The controller 10 stores component data for the upper-limit deterioration levels set for each of the high-voltage components 1 to 3 in a memory or the like. The controller 10 compares the deterioration levels of the high-voltage components 1 to 3 estimated by the deterioration level estimation unit 11 with the upper-limit deterioration levels of the high-voltage components 1 to 3, and when the deterioration levels of the high-voltage components 1 to 3 exceed the upper-limit deterioration levels, the controller 10 notifies the user to replace the high-voltage components 1 to 3 that have exceeded the upper-limit deterioration levels. The user is notified, for example, by displaying a message on an in-vehicle display. When the high-voltage components 1 to 3 to be replaced are replaced, the controller 10 resets the calculation result of the deterioration levels of the replaced high-voltage components 1 to 3 to their initial values.

[0031] For example, in the example of FIG. 2, the component limit lines (γ) of the plurality of high-voltage components 1 to 3 are determined by the degree of deterioration (α ３ The current tolerance (β ３ The deterioration degree (α ３ ) is equal to or greater than the upper limit of the deterioration level, the high-voltage component 3 becomes the component to be replaced. When the high-voltage component 3 is replaced, the controller 10 resets the calculation result of the deterioration level of the high-voltage component 3 to the initial value. When the deterioration level of the high-voltage component 3 is reset to the initial value, the current tolerance of the high-voltage component 3 becomes β ３ ' to β ３ Before returning to the initial value, the time domain (T ３ '), the lowest tolerated dose (β ３ ') was selected. If you reset the initial value, for example, the time domain (T ３ In some time domains included in the tolerance (β ２) has the smallest upper limit region of the current. The controller 10 updates the component limit lines (γ) of the multiple high-voltage components 1 to 3 by selecting the lowest withstand current for each time region. By updating the component limit lines (γ), the upper limit values ​​of the input / output power of the battery 4 are also updated. As a result, when the high-voltage components 1 to 3 are replaced, the degradation degree is reset and the input / output power of the battery 4 can be updated.

[0032] The controller 10 determines the upper limit (β ４ ) and multiple tolerances (β １ ~β ３ ) and set the upper limit power of the battery 4 based on the lowest withstand capacity.

[0033] 1 to 3: High-voltage component 4: Battery 10: Controller 11: Deterioration degree estimation unit 12: Withstand capacity calculation unit 13: Battery input / output control unit 100: Battery control system

Claims

1. A battery control device that controls the input and output of a vehicle battery connected to a motor, comprising a controller that estimates the degree of deterioration of multiple high-voltage components connected to the battery and controls the power input or output from the battery to the multiple high-voltage components, wherein the controller: estimates the degree of deterioration of each of the multiple high-voltage components based on at least one element of the integrated current value of the current flowing from the battery to the multiple high-voltage components, the usage time of the high-voltage components, and the number of times the high-voltage components have been used; calculates the current and / or temperature tolerance for each of the multiple high-voltage components based on the estimated degree of deterioration; sets an upper limit power for the battery based on the lowest tolerance among the multiple tolerances calculated for each of the multiple high-voltage components; and controls the input or output power of the battery to be below the upper limit power.

2. A battery control device according to claim 1, wherein the controller notifies the user to replace the high-voltage component when the estimated deterioration level reaches an upper limit deterioration level set for each high-voltage component, and when the high-voltage component is replaced, resets the calculated deterioration level to an initial value.

3. A battery control device according to claim 1 or 2, wherein the controller estimates the degree of deterioration of the plurality of high-voltage components based on the SOH of the battery.

4. A battery control device according to any one of claims 1 to 3, wherein the controller calculates the withstand current amount based on an upper limit temperature determined for each of the plurality of high-voltage components and the estimated degree of deterioration.

5. A battery control device according to any one of claims 1 to 4, wherein the withstand current amount is a value according to the time-current characteristics of each of the high-voltage components, and the time-current characteristics indicate the time until the load of the high-voltage component reaches an upper limit when a constant current is continuously passed through the high-voltage component.

6. A battery control method executed by a controller to control the input / output of a vehicle battery connected to a motor, wherein the controller: estimates the degree of deterioration of each of a plurality of high-voltage components connected to the battery based on at least one element of an integrated current value of the current flowing from the battery to the high-voltage components, the usage time of the high-voltage components, and the number of times the high-voltage components have been used; calculates the current and / or temperature tolerance for each of the plurality of high-voltage components based on the estimated degree of deterioration; sets an upper limit power for the battery based on the lowest tolerance among the plurality of tolerances calculated for each of the plurality of high-voltage components; and controls the input power or output power output from the battery to the plurality of high-voltage components to be equal to or less than the upper limit power.

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