JP2022032458A - Battery state estimation device, battery state estimation method and program - Google Patents

Abstract

To accurately estimate a state of charge of a secondary battery.SOLUTION: A battery state estimation device 200 comprises: a first estimation unit 210 for successively calculating a first estimate charge rate SOC1 which is an estimate of a charge rate SOC of a battery 100 and a current offset estimate Ioe which is an estimate of a current offset value Io of the battery 100 on the basis of an output current I which is a charge current or a discharge current of the battery 100, an output voltage V of the battery 100 and a cell surface temperature Ts of the battery 100 in a case where a predetermined condition is not established; and a second estimation unit 220 for successively calculating a temperature deviation estimate ΔTx which is an estimate of a deviation relating to a temperature of the battery 100, and a second estimate charge rate SOC2 which is the other estimate of the charge rate SOC, on the basis of the output current I, the output voltage V, the cell surface temperature Ts and a current offset specific estimate Ioes which is the current offset estimate Ioe in a case where the condition is changed from a non-established state to an established state, when the condition is established.SELECTED DRAWING: Figure 1

Description

The present invention relates to a battery state estimation device, a battery state estimation method and a program.

As a background technique in the present technical field, the following abstract of Patent Document 1 states, "A device for estimating the charge state of a secondary battery with high accuracy. A voltage measuring unit (22) for measuring a terminal voltage of a secondary battery (30). A current measuring unit (23) for measuring the charge / discharge current of the secondary battery 30 and a control unit (26) for estimating the charge state SOC of the secondary battery (30) are provided. The control unit (26) is charged. The SOC is estimated by integrating the charge / discharge current obtained by subtracting the current offset from the discharge current. The terminal voltage of the secondary battery (30) is estimated by the measurement model, and the terminal voltage measured by the voltage measuring unit (22). Using the error with, the first correction value of the estimated current offset and the second correction value of the estimated SOC are calculated, and the current offset and the SOC are corrected, respectively. "

International Publication No. 2012/098968

In Patent Document 1, the charge state of the secondary battery can be estimated based on the battery temperature, but it is difficult to accurately estimate the charge state.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a battery state estimation device, a battery state estimation method, and a program capable of accurately estimating the charge state of a secondary battery.

In order to solve the above problems, the battery state estimation device of the present invention has an output current which is a charging current or a discharging current of a battery, an output voltage of the battery, and a cell of the battery when a predetermined condition is not satisfied. Based on the surface temperature, the first estimated charge rate, which is an estimated value of the charge rate of the battery, and the current offset estimated value, which is an estimated value of the current offset value of the battery, are sequentially calculated. The estimation unit, the output current, the output voltage, the cell surface temperature, and the current offset estimated value when the condition changes from the unsatisfied state to the satisfied state when the condition is satisfied. A second that sequentially calculates a temperature deviation estimated value, which is an estimated value of deviation with respect to the temperature of the battery, and a second estimated charging rate, which is another estimated value of the charging rate, based on the specific estimated value. It is characterized by having an estimation unit of.

According to the present invention, the charge state of the secondary battery can be accurately estimated.

It is a block diagram of the battery state estimation apparatus by a preferable 1st Embodiment. It is an equivalent circuit diagram of a battery. It is a block diagram of the SOC / Io estimation part. It is a block diagram of the SOC / Ti estimation unit. It is a figure which shows an example of the transition of SOC, cell surface temperature, and cell internal temperature estimated value in 1st Embodiment. It is a flowchart which shows the operation of 1st Embodiment. It is a block diagram of the battery state estimation apparatus by a preferable 2nd Embodiment. It is a figure which shows the effect of SOC estimation by a preferable embodiment.

[First Embodiment]
<Structure of the first embodiment>
FIG. 1 is a block diagram of a battery state estimation device 200 (computer) according to a preferred first embodiment.
The battery state estimation device 200 estimates the state of the battery 100, which is a secondary battery, and has an SOC / Io estimation unit 210 (first estimation unit, first estimation means) and an SOC / Ti estimation unit 220. (Second estimation unit, second estimation means), a latch unit 230, a switching unit 240, and a switching condition determining unit 250 are provided. The battery 100 is, for example, a lithium ion battery.

Further, the battery 100 is equipped with a battery sensor unit 150 that detects the state of the battery 100. The battery sensor unit 150 measures the output voltage V, output current I, and cell surface temperature Ts of the battery 100, and supplies the measurement results to the battery state estimation device 200. Here, the output current I includes both a charge current and a discharge current. Further, the temperature sensor unit 160 measures the ambient temperature Te of the battery 100 and supplies the measurement result to the battery state estimation device 200.

The SOC / Io estimation unit 210 estimates the SOC (state of charge) of the battery 100 and the current offset value Io based on the output voltage V, the output current I, and the cell surface temperature Ts. do. The SOC estimated by the SOC / Io estimation unit 210 is referred to as "estimated charge rate SOC1 (first estimated charge rate)". Further, the estimated current offset value Io is referred to as "current offset estimated value Ioe". The latch unit 230 latches the current offset estimated value Ioe estimated by the SOC / Io estimation unit 210. The latched value is called "current offset specific estimated value Ioes".

The SOC / Ti estimation unit 220 determines the SOC of the battery 100 and the battery based on the output voltage V, the output current I, the cell surface temperature Ts, and the current offset specific estimated value Ioes latched by the latch unit 230. The cell internal temperature Ti of 100 is estimated. The SOC estimated by the SOC / Ti estimation unit 220 is referred to as "estimated charge rate SOC2 (second estimated charge rate)". The switching unit 240 selects one of the estimated charge rates SOC1 and SOC2 based on the control of the switching condition determination unit 250, and outputs the result as the estimated charge rate SOCE.

If the difference value "Ts-Te" between the cell surface temperature Ts and the ambient temperature Te is less than a predetermined threshold value (for example, 15 ° C.), the switching condition determination unit 250 sets the estimated charge rate SOC1 for the switching unit 240. Let me choose. On the other hand, when the difference value "Ts-Te" becomes the predetermined value or more, the switching unit 240 is made to select the estimated charge rate SOC2. Further, the latch unit 230 latches the current offset estimated value Ioe at the time when the selected estimated charge rate is switched from SOC1 to SOC2. As a result, the latch unit 230 continues to supply the current offset specific estimated value Ioes, which is the result of the latch, to the SOC / Ti estimation unit 220.

The case where the above-mentioned difference value "Ts-Te" becomes equal to or more than the above-mentioned threshold value (for example, 15 ° C.) means that, for example, when the ambient temperature Te is 2 ° C., the cell surface temperature Ts exceeds 17 ° C. This means that the battery 100 generates a considerable amount of heat due to the charge / discharge current, and it is considered that the cell internal temperature Ti of the battery 100 is further increased. In the present embodiment, the estimated charge rate SOC2 is selected as the estimated charge rate SOCE in such a case, thereby trying to estimate the SOC with high accuracy. When measuring the ambient temperature Te, it is preferable to keep the temperature sensor unit 160 away from heat-generating parts such as a battery 100 and a motor (not shown). Further, it is more preferable to arrange the temperature sensor units 160 at a plurality of places and adopt the lowest temperature among these measured temperatures as the ambient temperature Te.

FIG. 2 is an equivalent circuit diagram of the battery 100.
In FIG. 2, the resistor 106 and the capacitor 108 are connected in parallel to form a parallel circuit 122. Further, the resistor 110 and the capacitor 112 are connected in parallel to form a parallel circuit 123. The battery 100 can be considered to be equivalent to an ideal battery 102 that outputs the open circuit voltage OCV of the battery 100, a resistor 104, a parallel circuit 122, and a parallel circuit 123 connected in series. ..

Let the resistance values of the resistors 104, 106, 110 be R ₁ , R ₂ , R ₃ , and the capacitances of the capacitors 108, 112 be C ₂ , C ₃ . Also, let the time constants of the parallel circuits 122 and 123 be τ ₂ and τ ₃ . It can be considered that the output current I and the current offset value Io are equivalently flowing inside the battery 100. Further, the current offset value Io can be considered to be an error value of the output current I. In FIG. 2, the voltage drop in the resistor 104 is (I + Io) · R ₁ . Further, the voltage drop in the parallel circuits 122 and 123 is Vp1 and Vp2. Further, the battery terminal voltage CCV becomes equal to "OCV + (I + Io) · R ₁ + Vp1 + Vp2".

The open circuit voltage OCV, the resistance values R ₁ , R ₂ , R ₃ and the capacitances C ₂ and C ₃ shown in FIG. 2 change according to the temperature of the battery 100. Therefore, it is preferable to set these parameters for each temperature range. As the "temperature of the battery 100", the cell surface temperature Ts and the cell internal temperature Ti are considered, and ideally, the accuracy of the state estimation can be improved by using the cell internal temperature Ti. However, in a normal secondary battery, the cell internal temperature Ti cannot be directly measured, so the SOC and the like are estimated on the assumption that the cell surface temperature Ts and the cell internal temperature Ti are the same. Therefore, it is difficult to estimate SOC with high accuracy. Therefore, in the present embodiment, the cell internal temperature Ti is estimated by separately estimating the current offset value Io, which is a current error, and the temperature deviation “Ti—Ts”, and the SOC is estimated with high accuracy. It is something to do.

FIG. 3 is a block diagram of the SOC / Io estimation unit 210.
In FIG. 3, the SOC / Io estimation unit 210 includes the SOC estimation unit 211, the Io estimation unit 212, the CCV estimation unit 213, the Kalman gain estimation unit 214 (charge rate gain calculation unit), and the Kalman gain estimation unit 215. It includes a (gain calculation unit for current offset value), a subtraction unit 216, a multiplication unit 217a, 217b, and an addition unit 218a, 218b.

The estimated charge rate SOC 1, the current offset estimated value IOE, and the output current I are input to the SOC estimation unit 211. The SOC estimation unit 211 outputs the estimated charge rate SOC1x based on the input data. The Io estimation unit 212 outputs the current offset estimated value Iox based on the current offset estimated value Ioe and the predetermined initial value Io_ini.

The CCV estimation unit 213 outputs the battery terminal voltage estimated value CCVx (voltage estimated value), which is an estimated value of the battery terminal voltage CCV (see FIG. 2). The CCV estimation unit 213 includes a table in which the open circuit voltage OCV, the resistance values R ₁ , R ₂ , R ₃ and the time constants τ ₂ , τ ₃ are recorded in advance corresponding to various SOCs and temperatures. Then, the open circuit voltage OCV, the resistance values R ₁ , R ₂ , R ₃ and the time constants τ ₂ , τ ₃ are specified based on the input estimated charge rate SOC1x and the cell surface temperature Ts, and these specified parameters and these specified parameters are specified. The battery terminal voltage estimated value CCVx is output based on the output current I and the current offset estimated value Iox. The subtraction unit 216 subtracts the battery terminal voltage estimated value CCVx from the output voltage V, and outputs the result as the difference value ΔCCV.

The Kalman gain estimation unit 214 outputs the Kalman gain Gsoc (gain for charge rate) for SOC, which is sequentially obtained. Further, the Kalman gain estimation unit 215 outputs the Kalman gain Gio (gain for the current offset value) for the current offset value Io obtained sequentially. The multiplication unit 217a multiplies the difference value ΔCCV by the Kalman gain Gsoc and outputs the multiplication result Gsec · ΔCCV. The multiplication unit 217b multiplies the difference value ΔCCV by the Kalman gain Geo, and outputs the multiplication result Geo · ΔCCV.

The addition unit 218a adds the multiplication result Gsec · ΔCCV to the estimated charge rate SOC1x, and outputs the addition result as the estimated charge rate SOC1. The addition unit 218b adds the multiplication result Geo · ΔCCV to the current offset estimated value Iox, and outputs the addition result as the current offset estimated value Ioe. Each element of the SOC / Io estimation unit 210 described above updates the calculation result at a predetermined calculation cycle.

With the above configuration, the estimated charge rate SOC1 and the current offset estimated value Ioe are obtained by sequential calculation based on the following equations (1) and (2). In the following equations (1) and (2), t is the time, Δt is the calculation cycle, and Q is the full charge capacity [Ah] of the cell.

FIG. 4 is a block diagram of the SOC / Ti estimation unit 220.
In FIG. 4, the SOC / Ti estimation unit 220 includes an SOC estimation unit 221, a Ti estimation unit 222, a CCV estimation unit 223, a Kalman gain estimation unit 224 (charge rate gain calculation unit), and a Kalman gain estimation unit 225. It includes (a gain calculation unit for estimating the cell internal temperature), a subtraction unit 226, a multiplication unit 227a, 227b, and an addition unit 228a, 228b.

The estimated charge rate SOC2, the output current I, and the current offset specific estimated value Ioes latched by the latch unit 230 (see FIG. 1) are input to the SOC estimation unit 221. The SOC estimation unit 221 outputs the estimated charge rate SOC2x based on the input data.

The Ti estimation unit 222 has a cell internal temperature estimated value Tix and a temperature deviation estimated value in the next calculation cycle based on the cell internal temperature estimated value Tie which is an estimated value of the cell internal temperature Ti and the cell surface temperature Ts. ΔTx and are output sequentially. Here, the temperature deviation estimated value ΔTx is the difference between the cell internal temperature estimated value Tie and the cell surface temperature Ts. The CCV estimation unit 223 outputs the battery terminal voltage estimation value CCVx in the same manner as the CCV estimation unit 213 (see FIG. 3) of the SOC / Io estimation unit 210. However, the CCV estimation unit 223 outputs the battery terminal voltage estimated value CCVx based on the estimated charge rate SOC2 instead of the estimated charge rate SOC1 (see FIG. 3). The subtraction unit 226 subtracts the battery terminal voltage estimated value CCVx from the output voltage V, and outputs the result as the difference value ΔCCV.

The Kalman gain estimation unit 224 outputs the Kalman gain G soc for SOC that is sequentially obtained. Further, the Kalman gain estimation unit 225 outputs the Kalman gain Gti (gain for the cell internal temperature estimation value) for the cell internal temperature Ti which is sequentially obtained. The multiplication unit 227a multiplies the difference value ΔCCV by the Kalman gain Gsoc and outputs the multiplication result Gsec · ΔCCV. The multiplication unit 227b multiplies the difference value ΔCCV by the Kalman gain Gti and outputs the multiplication result Gti · ΔCCV.

The addition unit 228a adds the multiplication result Gsec · ΔCCV to the estimated charge rate SOC2x, and outputs the addition result as the estimated charge rate SOC1. The addition unit 228b adds the multiplication result Gti · ΔCCV to the cell internal temperature estimated value Tix, and outputs the addition result as the cell internal temperature estimated value Tie. Each element of the SOC / Ti estimation unit 220 described above updates the calculation result at each calculation cycle described above.

With the above configuration, the estimated charge rate SOC2 and the cell internal temperature estimated value Tie are obtained by sequential calculation based on the following equations (3) and (4). As in the above equations (1) and (2), t is the time, Δt is the calculation cycle, and Q is the full charge capacity [Ah] of the cell. Further, the current offset specific estimated value Ioees is a constant value, and the initial value Tie (0) of the cell internal temperature estimated value Tie (t) is the cell surface temperature Ts.

<Operation of the first embodiment>
Next, the operation of the first embodiment will be described.
FIG. 5 is a diagram showing an example of changes in SOC, cell surface temperature Ts, and cell internal temperature estimated value Tie in the first embodiment. In FIG. 5, the horizontal axis is time, and the vertical axis is temperature and SOC. The illustrated example is an example in which the battery 100 is discharged with a large current from a state where the SOC of the battery 100 is sufficiently high (for example, 90%). As a result, the cell surface temperature Ts and the cell internal temperature estimated value Tie of the battery 100 become higher with the passage of time. Further, the ambient temperature Te is constant, and the difference value "Ts-Te" is higher than the predetermined temperature difference Tse (for example, 15 ° C.) after the time t1. As a result, SOC1 is selected as the estimated charge rate SOCE (see FIG. 1) before time t1, and SOC2 is selected after time t1.

Generally, when estimating SOC, it is often the case that the SOC is estimated by integrating the current as in the above equation (1). At that time, if there is an error in the estimated current offset value Ioe, the SOC error increases with the current integration. However, the current offset value Io fluctuates little with the passage of time. On the other hand, in the example shown in FIG. 5, as the discharge time elapses, the cell surface temperature Ts of the battery 100 rises, the cell internal temperature estimated value Tie further rises, and the temperature deviation estimated value ΔTx which is the difference between the two rises. Is getting bigger.

Therefore, in the present embodiment, the accuracy of the current offset estimated value IOE can be improved while calculating the estimated charge rate SOC1 at the initial stage of estimating the SOC, that is, before the time t1. Then, by latching the current offset estimated value Ioe at time t1 as the current offset specific estimated value Ioe to the latch unit 230, the estimated charge rate SOC2 can be calculated based on the highly accurate current offset specific estimated value Ioe. ..

In FIG. 5, the error with respect to the true value of the estimated charge rate SOC1 increases as the time approaches t1. The error of the estimated charge rate SOC1 is not so related to the error of the current offset estimated value IOE, and is mainly due to the deviation between the cell surface temperature Ts and the cell internal temperature Ti of the battery 100. Then, after time t1, the SOC / Ti estimation unit 220 (see FIG. 1) calculates the estimated charge rate SOC2 while calculating the cell internal temperature estimated value Tie, so that the estimated charge rate SOC2 becomes true of the SOC over time. It gets closer to the value. Thereby, according to the present embodiment, it is possible to obtain an estimated charge rate SOCE close to the true value indicated by the alternate long and short dash line over the entire period shown in the figure.

FIG. 6 is a flowchart showing the operation of the first embodiment.
When the process proceeds to step S2 in FIG. 6, it is determined whether or not the "SOC2 selection condition" is satisfied. In the present embodiment, the "SOC2 selection condition" is a condition that "the difference value between the cell surface temperature Ts and the ambient temperature Te is higher than the predetermined temperature difference Tse (for example, 15 ° C.)".

If "No" is determined here, the process proceeds to step S6 (first estimation step), the estimation process by the SOC / Io estimation unit 210 is executed, and the switching unit 240 (see FIG. 1) has an estimated charge rate. The SOC1 is output as the estimated charge rate SOCE. On the other hand, if it is determined as "Yes" in step S2, the process proceeds to step S4 (second estimation step), the estimation process by the SOC / Ti estimation unit 220 is executed, and the switching unit 240 sets the estimated charge rate SOC2. Output as estimated charge rate SOCE.

[Second Embodiment]
FIG. 7 is a block diagram of the battery state estimation device 300 (computer) according to the preferred second embodiment. In the following description, the same reference numerals may be given to the parts corresponding to the respective parts of the first embodiment described above, and the description thereof may be omitted.
The battery state estimation device 300 of the second embodiment includes the switching condition determination unit 260 in place of the switching condition determination unit 250 (see FIG. 1) in the first embodiment, and the battery state estimation device 200 of the first embodiment is provided. Is different from. The clock signal CLK is supplied to the switching condition determination unit 260. Further, the temperature sensor unit 160 (see FIG. 1) for measuring the ambient temperature Te is not provided. In other respects, the battery state estimation device 300 is configured in the same manner as the battery state estimation device 200 of the first embodiment.

The switching condition determination unit 250 in the first embodiment described above selects either SOC1 or SOC2 as the estimated charge rate SOCE based on the difference value "Ts-Te" between the ambient temperature Te and the cell surface temperature Ts. The switching condition determination unit 260 of the present embodiment selects SOC2 as the estimated charge rate SOCE when any of the following two conditions is satisfied, and selects SOC1 when neither of the conditions is satisfied. This is because it is considered that the temperature difference between the cell surface temperature Ts and the cell internal temperature Ti is sufficiently large when any of the conditions 1 and 2 is satisfied.
Condition 1: An output current I of a predetermined current value or more is flowing from the battery 100 for a predetermined time of T1 or more.
-Condition 2: The amount of current of the battery 100 in the past predetermined time T2 is equal to or higher than the predetermined value.

[Effect of embodiment]
According to the preferred embodiment as described above, when the predetermined conditions are not satisfied, the battery state estimation devices 200 and 300 have an output current I which is a charging current or a discharging current of the battery 100 and an output current I of the battery 100. Based on the output voltage V and the cell surface temperature Ts of the battery 100, the first estimated charge rate (SOC1) which is an estimated value of the charge rate SOC of the battery 100 and the estimated value of the current offset value Io of the battery 100. The first estimation unit (210) that sequentially calculates the current offset estimated value Ioe, and when the condition is satisfied, the output current I, the output voltage V, the cell surface temperature Ts, and the condition are not satisfied. Based on the current offset specific estimated value Ioe, which is the current offset estimated value Ioe when the state changes from to the established state, the temperature deviation estimated value ΔTx, which is the estimated value of the deviation with respect to the temperature of the battery 100, and the charge rate SOC, etc. It is provided with a second estimated charge rate (SOC2), which is an estimated value of the above, and a second estimation unit (220) for sequentially calculating.

Thereby, according to the preferred embodiment, the charge state of the secondary battery can be accurately estimated.
FIG. 8 is a diagram showing the effect of SOC estimation according to a preferred embodiment.
The vertical axis of FIG. 8 indicates whether or not the cell internal temperature Ti is estimated, and the SOC estimation error can be made smaller by performing the cell internal temperature Ti than when not performing it. Further, the horizontal axis of FIG. 8 indicates whether or not the estimated value of the current offset value Io is corrected, and the correction can make the SOC estimation error smaller than the case where the correction is not performed. According to the present embodiment, since both the estimation of the cell internal temperature Ti and the correction of the estimated current offset value Io are applied, the estimation error of the SOC can be minimized.

Further, the first estimation unit (210) includes a subtraction unit 216 for calculating a voltage difference value (ΔCCV) which is a difference between the output voltage V and the voltage estimation value (CCVx) which is an estimation value of the output voltage V. The charge rate gain calculation unit (214) that calculates the charge rate gain (Gsoc), which is the gain corresponding to the charge rate SOC, and the current offset value gain (Gio), which is the gain corresponding to the current offset value Io, are calculated. A first estimated charge rate (CCVx) based on a charge rate gain (Gsoc), a current offset value gain (Gio), and a voltage estimate (CCVx). It is more preferable to sequentially calculate the SOC1) and the estimated current offset value Ioe. Thereby, the first estimated charge rate (SOC1) and the current offset estimated value IOE can be accurately calculated.

Further, the temperature deviation estimated value ΔTx is the difference between the cell internal temperature estimated value Tie of the battery 100 and the cell surface temperature Ts, and the second estimation unit (220) is the output voltage V and the estimated value of the output voltage V. The subtraction unit 226 that calculates the voltage difference value (ΔCCV), which is the difference from the voltage estimation value (CCVx), and the charge rate gain (Gsoc) that calculates the charge rate gain (Gsoc), which is the gain corresponding to the charge rate SOC. It is provided with a calculation unit (224) and a cell internal temperature estimation value gain calculation unit (225) for calculating a cell internal temperature estimation value gain (Gti) corresponding to the cell internal temperature estimation value Tie, and is a gain for charge rate. It is more preferable to sequentially calculate the second estimated charge rate (SOC2) and the cell internal temperature estimated value Tie based on (Gsoc), the cell internal temperature estimated value gain (Gti), and the voltage estimated value (CCVx). Thereby, the second estimated charge rate (SOC2) and the cell internal temperature estimated value Tie can be accurately calculated.

Further, it is more preferable that the predetermined condition is that the difference value Ts-Te between the cell surface temperature Ts and the ambient temperature Te of the battery 100 is equal to or larger than the predetermined temperature difference. Thereby, it can be appropriately determined whether to apply the first estimated charge rate (SOC1) or the second estimated charge rate (SOC2).

Further, the predetermined condition is further set to the condition that the output current I of the predetermined current value or more continues for the first predetermined time or more, or the amount of current within the second predetermined time in the past is the predetermined value or more. preferable. This eliminates the need to measure the ambient temperature Te by the temperature sensor unit 160 (see FIG. 1), so that the battery state estimation device 300 can be configured at a lower cost as compared with the embodiment in which the ambient temperature Te is measured. can.

Further, it is more preferable to further include one or a plurality of temperature sensor units 160 which are provided at a position sufficiently distant from the battery 100 and measure the ambient temperature Te of the battery 100. The "sufficiently distant position" is, for example, a "position substantially free from the influence of heat generation", whereby an accurate ambient temperature Te can be obtained.

[Modification example]
The present invention is not limited to the above-described embodiment, and various modifications are possible. The above-described embodiments are exemplified for the purpose of explaining the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Further, it is possible to delete a part of the configuration of each embodiment, or add / replace another configuration. In addition, the control lines and information lines shown in the figure show what is considered necessary for explanation, and do not necessarily show all the control lines and information lines necessary for the product. In practice, it can be considered that almost all configurations are interconnected. Possible modifications to the above embodiment are, for example, as follows.

(1) Since the hardware of the battery state estimation device 200 in the above embodiment can be realized by a general computer, the flowchart shown in FIG. 6 and other programs for executing the above-mentioned various processes are stored in the storage medium or stored in the storage medium. It may be distributed via a transmission line.

(2) Further, the battery state estimation device 200 may be realized by hardware-like processing using an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or the like.

100 Battery 160 Temperature sensor 200,300 Battery state estimation device (computer)
210 SOC / Io estimation unit (first estimation unit, first estimation means)
214 Kalman gain estimation unit (charge rate gain calculation unit)
215 Kalman gain estimation unit (gain calculation unit for current offset value)
216 Subtraction unit 220 SOC / Ti estimation unit (second estimation unit, second estimation means)
224 Kalman gain estimation unit (gain calculation unit for charge rate)
225 Kalman gain estimation unit (gain calculation unit for cell internal temperature estimation value)
226 Subtractor I Output current V Output voltage Io Current offset value S4 step (second estimation step)
S6 step (first estimation step)
Te Ambient temperature Ts Cell surface temperature Geo Kalman gain (gain for current offset value)
Gti Kalman gain (gain for cell internal temperature estimate)
Ioe Current offset estimated value SOC charge rate Tie Cell internal temperature estimated value ΔTx Temperature deviation estimated value CCVx Battery terminal voltage estimated value (voltage estimated value)
Gsoc Kalman gain (gain for charge rate)
Ioe's current offset specific estimated value SOC1 estimated charge rate (first estimated charge rate)
SOC2 estimated charge rate (second estimated charge rate)
ΔCCV difference value (voltage difference value)
Ts-Te difference value

Claims (8)

When a predetermined condition is not satisfied, the charge rate of the battery is estimated based on the output current which is the charge current or the discharge current of the battery, the output voltage of the battery, and the cell surface temperature of the battery. A first estimation unit that sequentially calculates a first estimated charge rate, which is a value, and a current offset estimated value, which is an estimated value of the current offset value of the battery.
When the condition is satisfied, the output current, the output voltage, the cell surface temperature, and the current offset specific estimated value which is the current offset estimated value when the condition changes from the unsatisfied state to the satisfied state. Based on the A battery state estimation device, characterized in that it comprises. The first estimation unit is
A subtraction unit that calculates a voltage difference value that is the difference between the output voltage and the voltage estimated value that is the estimated value of the output voltage.
A charge rate gain calculation unit that calculates a charge rate gain, which is a gain corresponding to the charge rate,
A current offset value gain calculation unit for calculating a current offset value gain, which is a gain corresponding to the current offset value, is provided.
The first aspect of claim 1, wherein the first estimated charge rate and the current offset estimated value are sequentially calculated based on the charge rate gain, the current offset value gain, and the voltage estimated value. Battery state estimation device. The temperature deviation estimated value is the difference between the cell internal temperature estimated value of the battery and the cell surface temperature.
The second estimation unit is
A subtraction unit that calculates a voltage difference value that is the difference between the output voltage and the voltage estimated value that is the estimated value of the output voltage.
A charge rate gain calculation unit that calculates a charge rate gain, which is a gain corresponding to the charge rate,
A cell internal temperature estimation value gain calculation unit for calculating a cell internal temperature estimation value gain corresponding to the cell internal temperature estimation value is provided.
The claim is characterized in that the second estimated charge rate and the cell internal temperature estimated value are sequentially calculated based on the charge rate gain, the cell internal temperature estimated value gain, and the voltage estimated value. The battery state estimation device according to 1. The battery state estimation device according to claim 1, wherein the condition is that the difference value between the cell surface temperature and the ambient temperature of the battery is a predetermined temperature difference or more. The condition is characterized in that the output current of the predetermined current value or more continues for the first predetermined time or more, or the amount of current within the second predetermined time in the past is the predetermined value or more. The battery state estimation device according to claim 1. The battery state estimation device according to claim 1, further comprising one or a plurality of temperature sensor units that are provided at a position sufficiently distant from the battery and that measure the ambient temperature of the battery. When a predetermined condition is not satisfied, the charge rate of the battery is estimated based on the output current which is the charge current or the discharge current of the battery, the output voltage of the battery, and the cell surface temperature of the battery. A first estimation step for sequentially calculating a first estimated charge rate, which is a value, and a current offset estimated value, which is an estimated value of the current offset value of the battery.
When the condition is satisfied, the output current, the output voltage, the cell surface temperature, and the current offset specific estimated value which is the current offset estimated value when the condition changes from the unsatisfied state to the satisfied state. Based on the , A battery state estimation method comprising. Computer,
When a predetermined condition is not satisfied, the charge rate of the battery is estimated based on the output current which is the charge current or the discharge current of the battery, the output voltage of the battery, and the cell surface temperature of the battery. A first estimation means for sequentially calculating a first estimated charge rate, which is a value, and a current offset estimated value, which is an estimated value of the current offset value of the battery.
When the condition is satisfied, the output current, the output voltage, the cell surface temperature, and the current offset specific estimated value which is the current offset estimated value when the condition changes from the unsatisfied state to the satisfied state. , A second estimation means for sequentially calculating a temperature deviation estimated value, which is an estimated value of the deviation with respect to the temperature of the battery, and a second estimated charge rate, which is another estimated value of the charge rate.
A program to function as.

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