JP2014017912A - Voltage regulation method, voltage regulation device, voltage regulation system and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately regulate a secondary battery voltage without using a four-terminal measurement method.SOLUTION: After a voltage measurement device measures a secondary battery subject to voltage regulation to acquire an open circuit voltage value, a voltage regulation device finds a surplus or deficit of capacity that is an estimate of electrical charge which must be stored or released for the open circuit voltage value of the secondary battery to reach a target voltage value. The secondary battery is then started to be charged or discharged, and when the estimate of electrical charge stored or released reaches the surplus or deficit of capacity, the secondary battery is stopped from being charged or discharged.

Description

  The present invention relates to a voltage adjustment technique for a secondary battery, and more particularly to a technique for adjusting a voltage so that the secondary battery has a desired open circuit voltage (OCV).

  The capacity of a secondary battery such as an in-vehicle lithium battery mounted on a hybrid vehicle, a plug-in hybrid vehicle, and an electric vehicle is one important index that represents the performance of such an automobile. It is said that the SOC (State of charge) application range of a hybrid vehicle is 30% to 60%, and in recent years, development to expand the SOC application range is important in order to improve the performance of the hybrid vehicle.

  Under such circumstances, it is desired to charge and discharge the secondary battery with high accuracy so as to obtain a desired SOC. However, it is difficult to directly measure the capacity of the secondary battery in order to know the SOC. Therefore, a charge / discharge test of the secondary battery is performed in advance, a correlation between the SOC and the OCV is obtained, an OCV (hereinafter referred to as “target voltage”) corresponding to a desired SOC is calculated, and the OCV of the secondary battery is calculated. In general, charging / discharging is performed so that becomes a target voltage. For example, if the target voltage corresponding to SOC 60% is 3.7V, the SOC of the secondary battery can be reduced to 60% by charging / discharging so that the OCV of the secondary battery is 3.7V. it can.

  The conventional secondary battery is charged by a CCCV (Constant Current / Constant Voltage) method using a four-terminal measurement method (see, for example, Non-Patent Document 1). FIG. 13A is a diagram illustrating a circuit for charging a secondary battery by a CCCV method using a four-terminal measurement method. FIG. 13B is a diagram illustrating the relationship among the charging time, the charging current, and the voltage of the secondary battery in the CCCV method. In the CCCV method, the current generator 1130 is controlled based on the voltage of the secondary battery 1150 measured by the voltage measuring device 1120, and the secondary battery 1150 is charged. Specifically, initially, the secondary battery 1150 is charged with a constant current, and when the voltage of the secondary battery 1150 reaches the target voltage, the battery is switched to the constant voltage and charged. The current decreases as it approaches the fully charged state, and charging at the target voltage is completed when the current stops flowing.

Usuda Shoji, “Introduction to Lithium-ion Battery Circuit Design”, Nikkan Kogyo Shimbun, April 2012

  In the conventional CCCV method, a four-terminal measurement method in which a current application terminal and a voltage measurement terminal are separated is used. Therefore, the conventional CCCV method cannot be applied to a secondary battery that can connect only two terminals. For example, when a plurality of secondary batteries are housed in a battery pack and only two voltage sense lines are provided from each secondary battery, the conventional CCCV method cannot be applied to each secondary battery.

  In the conventional CCCV method, voltage is measured while applying current to the secondary battery. Therefore, if the conventional CCCV method is executed using the two-terminal measurement method instead of the four-terminal measurement method, the voltage of the secondary battery cannot be accurately adjusted due to the influence of the line resistance accompanying the current application.

  The above problems apply not only when the voltage of the secondary battery is adjusted by charging, but also when the voltage of the secondary battery is adjusted by charging or discharging.

  This invention is made | formed in view of such a point, and it aims at providing the technique which performs the voltage adjustment of a secondary battery correctly, without using a 4-terminal measuring method.

  After obtaining the open circuit voltage value by measuring the secondary battery subject to voltage adjustment, the excess / deficiency capacity is an estimated value of the charge to be charged or discharged in order for the open circuit voltage value of the secondary battery to reach the target voltage value Get. The charging or discharging of the secondary battery is started, and when the estimated value of the charged or discharged charge reaches the excess / deficiency capacity, the charging or discharging of the secondary battery is terminated.

  The open-circuit voltage value can be measured with high accuracy by the two-terminal measurement method. During charging / discharging, control is performed based on whether the estimated value of the charged / discharged charge reaches the excess / deficiency capacity. Therefore, the voltage adjustment of the secondary battery can be accurately performed without using the four-terminal measurement method.

FIG. 1 is a diagram illustrating a voltage regulation system according to an embodiment. FIG. 2 is a flow for explaining the voltage adjustment method of the embodiment. FIG. 3 is a flow for explaining the pre-voltage adjustment of the embodiment. FIG. 4 is a flowchart for explaining voltage precision adjustment according to the embodiment. FIG. 5 is a diagram illustrating the relationship among the charge / discharge time, the charge / discharge current, and the voltage of the secondary battery in the embodiment. FIG. 6 is a diagram for comparing the embodiment with the CCCV method. FIG. 7 is a diagram for explaining a method of predicting OCV _n after waiting for return. FIG. 8 is a diagram illustrating a voltage regulation system according to the embodiment. FIG. 9 is a diagram illustrating a voltage regulation system according to the embodiment. FIG. 10 is a diagram illustrating the relationship between the charge / discharge time and the voltage of the secondary battery in the embodiment. FIG. 11 is a diagram illustrating a voltage regulation system according to the embodiment. FIG. 12 is a diagram illustrating the relationship between the charge / discharge time and the voltage of the secondary battery in the embodiment. FIG. 13A is a diagram illustrating a circuit for charging a secondary battery by a CCCV method using a four-terminal measurement method. FIG. 13B is a diagram illustrating the relationship among the charging time, the charging current, and the voltage of the secondary battery in the CCCV method.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
As illustrated in FIG. 1, the voltage regulation system 1 according to the first embodiment includes a voltage regulation device 110, a voltage measurement device 120 that performs voltage measurement using a two-terminal measurement method, and a current generation unit, a current measurement unit, and a discharge resistance. The voltage generator of the secondary battery 150 is adjusted. The voltage adjustment device 110 includes a pre-voltage adjustment unit 111, a voltage recovery wait processing unit 112, a determination unit 113, a voltage precision adjustment unit 114, a control unit 115, and a memory 116. The voltage adjustment device 110 is a special device configured by, for example, reading a predetermined program into a known or dedicated computer. The control unit 115 controls the entire processing of the voltage adjustment device 110. The memory 116 stores data obtained by each unit, and the data stored in the memory 116 is used for processing of each unit. The voltage adjustment device 110 is connected to and controls the voltage adjustment device 110 and the voltage measurement device 120.

Hereinafter, the voltage adjustment method of this embodiment will be described with reference to FIGS.
<Pre-voltage adjustment>
After the control unit 115 initializes the variable n to 1, the pre-voltage adjustment unit 111 executes pre-voltage adjustment (step S102). The purpose of performing the pre-voltage adjustment is to obtain a capacitance Q ₀ necessary for obtaining a reference capacitance value refQ ₁ that is required in the voltage precise adjustment (step S109) described later. If a constant or a value obtained in advance is the capacity Q ₀ , the pre-voltage adjustment may not be performed.

Details of the pre-voltage adjustment will be described with reference to FIGS.
The pre-voltage adjustment unit 111 controls the voltage measurement device 120, and the voltage measurement device 120 measures the open circuit voltage of the secondary battery 150 to be voltage adjusted before the start of charging / discharging, and the open circuit voltage value OCV of the secondary battery 150. _{Get 0} . The open circuit voltage value OCV ₀ is stored in the memory 116 (step S102a).

The pre-voltage adjustment unit 111 subtracts the open circuit voltage value OCV ₀ obtained in step S102a from a predetermined target voltage value finalV to obtain a subtraction value ΔV ₀ .
ΔV ₀ = finalV−OCV ₀
The subtraction value ΔV ₀ is stored in the memory 116 (step S102b).

The pre-voltage adjusting unit 111 determines the charging / discharging operation of the secondary battery 150 as follows according to the polarity of the subtraction value ΔV ₀ .
・ If ΔV ₀ > 0, adjust the voltage in the charging operation.
・ If ΔV ₀ <0, adjust the voltage by discharging.
That pre-voltage adjustment unit 111, the subtraction value [Delta] V ₀ starts charging the secondary battery 150 in the case of positive subtraction value [Delta] V ₀ starts to discharge of the secondary battery 150 for negative. The pre-voltage adjustment unit 111 controls the current generator 130 according to the determination content, and charges / discharges the secondary battery 150. When ΔV ₀ = 0, the voltage adjustment may be performed by the charging operation, the voltage adjustment may be performed by the discharging operation, or the pre-voltage adjusting unit 111 is set with the capacity Q ₀ = 0. The voltage adjustment itself may be ended. In the example of FIG. 3, the pre-voltage adjustment unit 111 determines whether ΔV ₀ > 0 (step S102c). If ΔV ₀ > 0, charging of the secondary battery 150 is started (step S102d), and ΔV ₀ If not> 0, discharging of the secondary battery 150 is started (step S102e).

The voltage measuring device 120 measures the voltage of the secondary battery 150 at the start time of charging or discharging of the secondary battery 150 or at a certain time after the start time to obtain the closed circuit voltage V ₀ . For example, the voltage measuring device 120 measures the voltage immediately after the start of charging or discharging to obtain the closed circuit voltage V ₀ . The obtained closed circuit voltage V ₀ is stored in the memory 116 (step S102f). Since the voltage measurement device 120 performs voltage measurement by the two-terminal measurement method, the closed circuit voltage V ₀ changes from the above-described open circuit voltage value OCV ₀ according to the direction and strength of the current. For example, in the case of charging, the closed circuit voltage V ₀ is larger than the open circuit voltage value OCV ₀ , and in the case of discharging, the closed circuit voltage V ₀ is smaller than the open circuit voltage value OCV ₀ . Considering such a change, the pre-voltage adjusting unit 111 adds the closed circuit voltage V ₀ and the subtraction value ΔV ₀ to obtain the charge / discharge end voltage value targV.
targetV = ΔV ₀ + V ₀
The charge / discharge end voltage value targV is stored in the memory 116 (step S102g).

Thereafter, while charging / discharging the secondary battery 150, the voltage measuring device 120 measures the closed circuit voltage V _m of the secondary battery 150 at a constant time interval Δt ₀ (where Δt ₀ > 0). Also at the same timing as the measurement of the closed circuit voltage V _m, measuring the current value I _m of the charge or discharge by current measurement unit of the current generator 130. Current value I _m at the time of charging is a positive value, the current value I _m at the discharge is negative value, in the present embodiment, both a constant current (Fig. 5). The obtained closed circuit voltage V _m and current value I _m are stored in the memory 116. When the measured closed circuit voltage V _m reaches the charge / discharge end voltage value targV, the pre-voltage adjustment unit 111 controls the current generator 130 to set the current value to 0 A (for example, the generated current of the current generator 130). Or the discharge resistance of the current generator 130 is disconnected from the secondary battery 150), and charging or discharging of the secondary battery 150 is terminated. The pre-voltage adjusting unit 111 obtains a capacity Q ₀ that is an estimated value of the charged or discharged charge from the start to the end of charging or discharging (steps S102d and S102e) and stores it in the memory 116. The capacity Q ₀ when charged is a positive value, and the capacity Q ₀ when discharged is a negative value.

In the example of FIG. 3, first, the pre-voltage adjustment unit 111 initializes a variable m representing the number of measurements to 1 (step S102h). After a certain time interval Δt ₀ , the voltage measuring device 120 and the current generator 130 obtain the closed circuit voltage V _m and the charging or discharging current value I _m of the secondary battery 150, and store them in the memory 116 (step S102i). Pre voltage adjusting unit 111 determines whether the closed circuit voltage _{V m} has reached the discharge termination voltage value TargV. For example, the pre-voltage adjustment unit 111 determines that the closed circuit voltage V _m has reached the charge / discharge end voltage value targ V when V _m ≧ target V is satisfied during charging, and the closed circuit voltage V when V _m ≦ target V is satisfied during discharging. _It is determined that _m has reached the charge / discharge end voltage value targV (step S102j). When determining that the closed circuit voltage V _m has not reached the charge / discharge end voltage value targV, the pre-voltage adjusting unit 111 sets m + 1 as a new m (step S102k), and returns to the process of step S102i. On the other hand, if the pre-voltage adjustment unit 111 determines that the closed circuit voltage V _m has reached the charge / discharge end voltage value targ V, the pre-voltage adjustment unit 111 obtains the capacity Q ₀ as follows and stores it in the memory 116 to charge the secondary battery 150 or End the discharge.
Q ₀ = Σ _m (I _m × Δt ₀ )
= (I ₁ × Δt ₀ ) + (I ₂ × Δt ₀ ) +... + (I _{M (0)} × Δt ₀ )
However, M (0) is the value of m when it is determined that the closed circuit voltage V _m has reached the charge / discharge end voltage value targV. Incidentally, rather than first determine the capacity Q ₀ after closed circuit voltage V _m has reached the discharge termination voltage value TargV, each time to obtain a current value I _m, sequential, it may be obtained the value of the capacity Q _0.

<Voltage recovery waiting process>
After charging / discharging is completed, the secondary battery 150 in the no-load state has an action to restore the voltage value, and the open circuit voltage value fluctuates. Therefore, the voltage recovery waiting processing unit 112 waits until the open circuit voltage value of the secondary battery 150 is stabilized. That is, the voltage recovery wait processing unit 112 waits until the voltage recovery waiting time for stabilizing the open circuit voltage value of the secondary battery 150 elapses after the charging or discharging of the secondary battery 150 is completed. For example, the voltage recovery waiting processing unit 112 terminates charging or discharging and sets the current value of the current generator 130 to 0 A, and then the voltage measuring device 120 measures the open circuit voltage of the secondary battery 150 at regular time intervals. Wait for the open circuit voltage to stabilize. The determination as to whether the open circuit voltage has stabilized is made, for example, by determining whether the amount of change (the magnitude of the difference) between the previously measured open circuit voltage and the currently measured open circuit voltage is equal to or less than a threshold value (step S103).

<Target voltage arrival judgment>
After the elapse of the voltage recovery waiting time (after the open circuit voltage is stabilized), the voltage measuring device 120 measures the secondary battery 150 and obtains the open circuit voltage value OCV _n under the control of the determination unit 113. The open circuit voltage value OCV _n is stored in the memory 116 (step S104).

  Next, the determination unit 113 determines whether n exceeds a predetermined number of retries (however, the number of retries is a positive integer) (step S105). When it is determined that n exceeds the number of retries, the control unit 115 ends the process assuming that the voltage adjustment has failed (step S106).

When it is determined that n does not exceed the number of retries, the determination unit 113 next determines whether the open circuit voltage value OCV _n has reached the target voltage value finalV. For example, the determination unit 113 determines that the open circuit voltage value OCV _n has reached the target voltage value finalV when satisfying finalV−β1 ≦ OCV _n ≦ finalV + β2 (where β1 and β2 are positive constants for specifying the allowable range). and determines that the open circuit voltage value OCV _n has not reached the target voltage value finalV if not satisfied. When it is determined that the open circuit voltage value OCV _n has reached the target voltage value finalV, the control unit 115 ends the process assuming that the voltage adjustment has been successful. Note that _n in the case where it is determined that the open circuit voltage value OCV _n has reached the target voltage value finalV corresponds to “positive integer N” (step S108). When it is determined that the open circuit voltage value OCV _n has not reached the target voltage value finalV, the following voltage precision adjustment is performed.

<Precise voltage adjustment>
In the precise voltage adjustment, the open circuit voltage value of the secondary battery 150 is adjusted to the target voltage value finalV (step S109).

Details of the pre-voltage adjustment will be described with reference to FIGS.
The precise voltage adjustment unit 114 obtains an excess / deficiency capacity targQ _n that is an estimated value of charge to be charged or discharged in order for the open circuit voltage value of the secondary battery 150 to reach the target voltage value finalV. For this purpose, first, the voltage precision adjustment unit 114 uses Q _n−1 , OCV _n, and OCV _n−1 to obtain a reference capacitance value refQ _n that is a capacitance per change in the open circuit voltage and stores it in the memory 116. The voltage precise adjustment unit 114 obtains a reference capacitance value refQ _n (where refQ _n ≧ 0), for example, as follows.
_{refQ n = Q n-1 /} (OCV n -OCV n-1)
The reference capacitance value refQ _n is stored in the memory 116 (step S109a).

Based on the previously obtained reference capacitance value refQ _n , the precise voltage adjustment unit 114 obtains an excess / deficiency capacitance targetQ _n necessary for the open circuit voltage value to reach the target voltage value finalV. For example, the voltage fine adjustment unit 114, using the reference capacitance value RefQ _n and the target voltage value finalV and the open circuit voltage value OCV _n, determine the excess and deficiency capacity TargQ _n as follows.
targetQ _n = refQ _n × (finalV−OCV _n )
That is, excessive or insufficient capacity TargQ _n in this example, satisfies the _{targQ n = Q n-1 ×} (finalV-OCV n) / (OCV n -OCV n-1). The excess / deficiency capacity targQ _n is stored in the memory 116 (step S109b).

Next, the precise voltage adjustment unit 114 obtains a subtraction value ΔV _n obtained by subtracting the open circuit voltage value OCV _n from the target voltage value finalV.
ΔV _n = finalV−OCV _n
The subtraction value ΔV _n is stored in the memory 116 (step S109c).

Voltage fine adjustment section 114, the polarity of the subtraction value [Delta] V _n, determines the charge and discharge operations of the secondary battery 150 as follows.
・ If ΔV _n > 0, adjust the voltage in the charging operation.
・ If ΔV _n <0, adjust the voltage by discharging.
That voltage fine adjustment unit 114, the subtraction value [Delta] V _n starts charging the secondary battery 150 in the case of positive subtraction value [Delta] V _n begins to discharge of the secondary battery 150 for negative. The voltage precise adjustment unit 114 controls the current generator 130 in accordance with this determination content, and charges and discharges the secondary battery 150. In the example of FIG. 4, the voltage precise adjustment unit 114 determines whether ΔV _n > 0 (step S109d). If ΔV _n > 0, charging of the secondary battery 150 is started (step S109e), and ΔV _n If not> 0, the secondary battery 150 starts to be discharged (step S109f).

Thereafter, while charging / discharging the secondary battery 150, the voltage measurement device 120 measures the closed circuit voltage V _m of the secondary battery 150 at a constant time interval Δt _n (where Δt _n > 0). Also at the same timing as the measurement of the closed circuit voltage V _m, measuring the current value I _m of the charge or discharge by current measurement unit of the current generator 130. Current value I _m at the time of charging is a positive value, the current value I _m at the discharge is negative value, in the present embodiment, both a constant current (Fig. 5). The obtained closed circuit voltage V _m and current value I _m are stored in the memory 116.

Voltage fine adjustment unit 114, since the start of charging or discharging (step S109e or S109f), when the capacity _{Q n} 'is an estimate of the charge or discharge electric charge has reached the excess and deficiency capacity TargQ _n, current generation The device 130 is controlled to set the current value to 0 A, and the charging or discharging of the secondary battery 150 is finished. The voltage precise adjustment unit 114 obtains a capacity Q _n that is an estimated value of the charged or discharged charge from the start to the end of charging or discharging (step S109e or S109f) and stores it in the memory 116. The capacity Q _n when charged is a positive value, and the capacity Q _n when discharged is a negative value.

In the example of FIG. 4, first, the voltage precision adjustment unit 114 initializes a variable m indicating the number of measurements to 1 (step S109g). After a certain time interval Delta] t _n, current generator 130 can obtain a current value _{I m} of the secondary battery 150, and stores them in the memory 116 (step S109H). The precise voltage adjustment unit 114 determines whether the capacity Q _n ′ = (I ₁ × Δt _n ) + (I ₂ × Δt _n ) +... + (I _m × Δt _n ) has reached the excess / deficiency capacity targQ _n. judge. For example, when the voltage fine adjustment unit 114 determines that reaches the excess or deficiency capacity targQ _n 'capacity _{Q n} when satisfying ≧ targQ _{n' Q n} at the time of charging, satisfying _{Q n} '≦ _{targQ n} during discharging It is determined that the capacity Q _n ′ has reached the excess / deficiency capacity targetQ _n (step S109j). If the voltage precision adjustment unit 114 determines that the capacity Q _n ′ has not reached the excess / deficiency capacity targetQ _n , m + 1 is set as a new m (step S109k), and the process returns to step S109h. Voltage fine adjustment unit 114 'determines that the has reached the excess and deficiency capacity TargQ _n, the capacity _{Q n} at that time' capacity _{Q n} stored in the memory 116 as a capacity _{Q n,} the secondary battery 150 charging or End the discharge. That is, the capacity Q _n satisfies the following.
Q _n = Σ _m (I _m × Δt _n )
= (I ₁ × Δt _n ) + (I ₂ × Δt _n ) +... + (I _{M (n)} × Δt _n )
However, M (n) is the value of m when it is determined that the capacity Q _n ′ has reached the excess / deficiency capacity targetQ _n .

  After the voltage precision adjustment (step S109), n + 1 is set as a new n (step S110), and the process returns to step S103.

<Features of this embodiment>
The open circuit voltage values OCV ₀ and OCV _n can be measured with high accuracy by the two-terminal measurement method. In particular, in the present embodiment, after charging or discharging of the secondary battery 150 is completed, and after a voltage return waiting time for stabilizing the open circuit voltage value of the secondary battery 150 has elapsed, the secondary battery 150 is measured and the open circuit voltage is measured. The value OCV _n is obtained. Thereby, the open circuit voltage value OCV _n can be obtained with higher accuracy.

During charging / discharging in the pre-voltage adjustment, the open circuit voltage value cannot be measured with high accuracy. However, by controlling the charging / discharging end voltage value targV as a reference, the voltage adjustment of the secondary battery can be performed with a certain degree of accuracy. Further, by using the capacity Q ₀ obtained in the pre-voltage regulator, it is possible to obtain better excess capacity TargQ ₁ at a voltage fine adjustment accuracy.

During charging and discharging at a voltage fine adjustment, the estimated value of the charge and discharge electric charges is controlled based on whether reaching the excess or deficiency capacity targQ _n. Therefore, the voltage adjustment of the secondary battery can be accurately performed without using the four-terminal measurement method.

  Furthermore, in this embodiment, there is no need to decrease the current value during charging / discharging. Therefore, voltage adjustment can be completed in a short time compared to the conventional CCCV method in which the current value decreases after the start of constant voltage charging. In the case of the example of FIG. 6, by using the voltage adjustment method of this embodiment, the voltage adjustment can be completed in about 1/3 of the charging time of the conventional CCCV method.

[Second Embodiment]
In a secondary battery such as a lithium secondary battery, the operating voltage and the dangerous voltage are close to each other, and voltage management during charge / discharge operation is important. In the second embodiment, hardware and software safety measures are applied to the first embodiment. Only differences from the first embodiment will be described below. About the matter which is common in 1st Embodiment, description is abbreviate | omitted using the same reference number as 1st Embodiment.

<Hardware safety measures>
In the voltage regulation system 2 of the present embodiment, in order to protect the secondary battery 150, a constant current generator 230 that can respectively set upper and lower limiter voltages is used instead of the current generator 130 of the first embodiment (see FIG. 1). For example, a voltage corresponding to SOC 0% is set as the lower limiter voltage, and a voltage corresponding to SOC 100% is set as the upper limiter voltage. This prevents the secondary battery 150 from reaching the dangerous voltage.

<Software safety measures>
The voltage adjustment system 2 of the present embodiment includes a voltage adjustment device 210 including a pre-voltage adjustment unit 211 instead of the voltage adjustment device 110 including the pre-voltage adjustment unit 111 (FIG. 1). In this embodiment, after the closed circuit voltage V ₀ is obtained in step S102f, the pre-voltage adjustment unit 211 determines whether the added value of the closed circuit voltage V ₀ and the subtraction value ΔV ₀ is less than a predetermined limiter voltage (threshold). Is determined (FIG. 3 / step S202g). If the addition value of the closed circuit voltage V ₀ and the subtraction value ΔV ₀ is less than the limiter voltage, the pre-voltage adjustment unit 211 sets the charge / discharge end voltage value targV = ΔV ₀ + V ₀ and stores it in the memory 116 (step 116). S102g). If the addition value of the closed circuit voltage V ₀ and the subtraction value ΔV ₀ exceeds the limiter voltage, the pre-voltage adjustment unit 211 sets the value α equal to or lower than the limiter voltage as the charge / discharge end voltage value targV and stores it in the memory 116 ( Step S202h). Thereby, the voltage of the secondary battery 150 is prevented from exceeding the limiter voltage.

[Third Embodiment]
In the voltage adjustment method of the first embodiment, voltage adjustment is performed using the open circuit voltage value after charge / discharge execution as an index, but the open circuit voltage value immediately after charge / discharge execution is not stable, until the voltage recovery waiting time elapses. Waiting time is required. However, the ratio of the voltage recovery waiting time to the entire voltage adjustment time is not small. For example, if the voltage recovery waiting time for one time is 5 minutes, the total voltage recovery waiting time when the voltage adjustment can be performed by two voltage precision adjustments is 15 minutes. If the stabilized open circuit voltage value can be predicted without waiting for the voltage recovery waiting time to elapse, the voltage adjustment time can be shortened. In the third embodiment, the open circuit voltage value after the voltage recovery waiting time has elapsed is estimated, and the estimated value is OCV _n . That is, the open circuit voltage value OCV _n of the present embodiment is obtained by using the secondary battery open circuit voltage values measured at a plurality of times after the end of charging or discharging of the secondary battery. It is an open circuit voltage estimated value. Only differences from the first embodiment will be described below. About the matter which is common in 1st Embodiment, description is abbreviate | omitted using the same reference number as 1st Embodiment.

  The voltage adjustment system 3 of this embodiment includes a voltage adjustment device 310 including a voltage recovery wait processing unit 312 instead of the voltage adjustment device 110 including the voltage recovery wait processing unit 112. In the voltage adjustment method of this embodiment, step S303 is executed instead of step S103, and step S304 is executed instead of step S104. Below, the process of step S303 and S304 is demonstrated.

<Step S303>
In step S303, the voltage recovery waiting processing unit 312 uses the open circuit voltage values of the secondary battery 150 measured at a plurality of times after the end of charging or discharging of the secondary battery 150, and opens the secondary battery after voltage stabilization. Find the voltage estimate. For example, the voltage recovery wait processing unit 312 performs three equal time points t (0), t (1), t (2) (t (0) <t (1) <after completion of step S102 or S110. At t (2)), the open circuit voltage values OCV (t (0)), OCV (t (1)), and OCV (t (2)) of the secondary battery 150 are measured by the voltage measuring device 120, respectively. An open circuit voltage estimated value is obtained by equation (1) (see FIG. 7).
Open circuit voltage estimated value = OCV (t (0)) × {OCV (t (1)) − OCV (t (0))} / {2 × OCV (t (1)) − OCV (t (2)) − OCV (t (0))} (1)

<Step S304>
In step S304, the voltage recovery waiting processing unit 312 stores the open circuit voltage estimated value obtained at step S304 in the memory 116 as the open circuit voltage value OCV _n.

According to this embodiment, precise voltage adjustment can be performed without waiting for the voltage recovery waiting time to elapse. For example, one voltage recovery waiting time is 5 minutes, and three points (t (0), t (1), t (3) after 10 seconds, 20 seconds, and 30 seconds after the completion of step S102. )), The open circuit voltage values OCV (t (0)), OCV (t (1)), and OCV (t (2)) are measured to obtain an open circuit voltage estimated value, which is set as the open circuit voltage value OCV _n . In this case, the time from the end of step S102 or S110 until the voltage fine adjustment can be started can be shortened from 5 minutes to 30 seconds (from time t (4) to time t (3)).

[Fourth Embodiment]
In 4th Embodiment, the voltage adjustment with respect to all the secondary batteries in a battery pack is performed. This embodiment can be executed using any of the methods of the first to third embodiments. Only differences from the first to third embodiments will be described below. About the matter which is common in 1st-3rd embodiment, description is abbreviate | omitted using the same reference number as 1st-3rd embodiment.

  As illustrated in FIG. 8, the voltage regulation system 4 of the fourth embodiment includes a voltage regulation device 410, a current generation device 130 (or 230) and a voltage measurement device 120 connected to the voltage regulation device 410, and a voltage regulation. The device 410, the current generator 130 (or 230), and the scanner 440 connected to the voltage measuring device 120, perform voltage adjustment for the secondary battery in the battery pack 450. The voltage adjustment device 110 includes a pre-voltage adjustment unit 111 (or 211), a voltage recovery wait processing unit 112 (or 312), a determination unit 113, a voltage precision adjustment unit 114, a control unit 415, and a memory 116. The control unit 415 controls the entire processing of the voltage adjustment device 410 and the scanner 440.

As illustrated in FIG. 9, the battery pack 450 includes K secondary batteries BAT ₁ ,..., BAT _K connected in series (where K is an integer of 2 or more). The scanner 440 includes a plurality of switches that can be turned on / off by the control unit 415. These switches on and off, the secondary battery _BAT 1, · · ·, secondary batteries selected from BAT _K BAT _k [However k = 1, · · ·, K] current generator across the 130 (or 230) and / or the voltage measuring device 120 can be connected. Thereby, charging / discharging and voltage measurement of the selected secondary battery BAT _k are possible. As illustrated in FIG. 9, in this embodiment, each switch interposed between the current generator 130 (or 230) and each secondary battery BAT _k , the voltage measuring device 120, and each secondary battery BAT _k The intervening switches are independent of each other. Therefore, the secondary battery that performs charging / discharging by connecting the current generator 130 (or 230) and the secondary battery that performs voltage measurement by connecting the voltage measuring device 120 can be controlled independently. The state where the switch has been switched to connect the current generator 130 (or 230) and / or voltage measuring device 120 on both ends of the secondary battery BAT _k referred to as Ch-k.

<Voltage adjustment method>
Voltage regulator 410, the secondary battery _BAT 1 in the battery pack 450, and ..., secondary batteries selected from BAT _K BAT _k [However k = 1, ..., K] and the voltage adjusted, the The voltage adjustment is performed as described in the first to third embodiments. This is executed for all the secondary batteries BAT ₁ ,..., BAT _K.

As illustrated in FIG. 10, the control unit 415 includes the secondary batteries BAT ₁ , BAT ₂ ,..., BAT _{K in} the order of Ch−1, Ch−2,. The pre-voltage adjustment described in the first embodiment (steps S101 and S102) is performed by controlling the scanner 440 such that the secondary battery BAT _k selected by each Ch is a voltage adjustment target. I do. For example, in the example of FIG. 10, after pre-voltage adjustment ((t (i, 1) to t (i, 2)) for Ch-i [where i = 1,..., K−1], Ch− Pre-voltage adjustment ((t (i + 1, 1) to t (i + 1, 2)) is performed on (i + 1).

After all the pre-voltage adjustment has been completed, the control unit 415, Ch-1, Ch-2 , ···, in the order of Ch-K, the secondary battery _{BAT 1,} BAT 2, · · ·, the BAT _K The scanner 440 is controlled so that each becomes a voltage adjustment target, and each secondary battery BAT _k selected by each Ch is set as a voltage adjustment target, and the processes of steps S103 (or S303) to S108 are executed. In the case of the example of FIG. 10, after the processing of steps S103 (or S303) to S108 for Ch-i ((t (i, 4) to t (i, 5)), step S103 for Ch- (i + 1) (or The processing of (S303) to S108 ((t (i + 1,4) to t (i + 1,5)) is performed.

When voltage adjustment is performed by the method of the first or second embodiment, the following control is performed (see FIG. 10).
(1) The voltage adjustment device 410 further opens the open circuit voltage value of the secondary battery BAT _i after completion of charging or discharging of the secondary battery BAT _i subject to voltage adjustment (charging or discharging in the pre-voltage adjustment or precise voltage adjustment). the after the elapse voltage returning waiting time T _i for stabilizing may obtain the open-circuit voltage value OCV _n of the secondary battery BAT _i. It should be noted that, after the charging or discharging of the secondary battery BAT _i subject to voltage adjustment is completed, the voltage measuring device 120 measures the open circuit voltage value of the secondary battery BAT _i at regular time intervals, and the time until the open circuit voltage value becomes stable (e.g., time to variation of the open circuit voltage value is equal to or less than a predetermined value) to a voltage return waiting time T _i. In the example of FIG. 10, after the pre-voltage adjustment (t (i, 1) to t (i, 2)) for the secondary battery BAT _i (Ch-i) is finished, the time t (i, 3) until the time the voltage returning latency _{T i,} the open-circuit voltage value at time t (i, 3) and the open circuit voltage value OCV _n of the secondary battery _BAT i (Ch-i). The same applies to the voltage return waiting time after the voltage precision adjustment.
(2) The voltage adjustment device 410, after completion of charging or discharging of the secondary battery BAT _i (charging or discharging in pre-voltage adjustment or voltage precise adjustment), before obtaining the open circuit voltage value OCV _n of the secondary battery BAT _i Then, charging or discharging of the secondary battery BAT _{i + 1} (charging or discharging with precise voltage adjustment) is started. In the example of FIG. 10, after completion of the pre-voltage adjustment for the secondary battery BAT _i (Ch-i) (t (i, 2)), the open circuit voltage value OCV _n of the secondary battery BAT _i at t (i, 3). Is obtained, the pre-voltage adjustment of another secondary battery BAT _{i + 1} is started at t (i + 1, 1). Thus, without waiting for the elapse of the voltage return waiting time T _i of the secondary battery BAT _i, by initiating another charging or discharging of the secondary battery BAT i + _1, the voltage adjustment time of the entire battery pack 450 Can be shortened.

[Fifth Embodiment]
The fifth embodiment is a modification of the fourth embodiment and has a configuration in which the scanner is made inexpensive. Only differences from the fourth embodiment will be described below. Specifically, each switch interposed between the current generator 130 (or 230) and each secondary battery BAT _k may be a switch interposed between the voltage measuring device 120 and each secondary battery BAT _k. Function. Thereby, the number of switches of the scanner can be reduced and the cost can be reduced.

  As illustrated in FIG. 8, the voltage adjustment system 5 of the fifth embodiment includes a voltage adjustment device 510, a current generation device 130 (or 230) and a voltage measurement device 120 connected to the voltage adjustment device 510, and a voltage adjustment. The device 510, the current generator 130 (or 230), and the scanner 540 connected to the voltage measuring device 120, perform voltage adjustment for the secondary battery in the battery pack 450. The voltage regulator 510 is obtained by replacing the controller 415 of the voltage regulator 410 with a controller 515.

As illustrated in FIG. 11, the scanner 540 includes a plurality of switches that can be controlled on and off by the control unit 515. These switches on and off, the secondary battery _BAT 1, · · ·, secondary batteries selected from BAT _K BAT _k [However k = 1, · · ·, K] current generator across the 130 (or 230) and the voltage measuring device 120 can be connected. In this embodiment, the current generator 130 (or 230) and the voltage measuring device 120 are connected in parallel to the scanner 540, and are interposed between the current generator 130 (or 230) and each secondary battery BAT _k. Each switch also functions as a switch interposed between the voltage measuring device 120 and each secondary battery BAT _k . Therefore, the current generator 130 (or 230) and the voltage measuring device 120 are connected to the same secondary battery BAT _k .

As illustrated in FIG. 12, the control unit 515 includes the secondary batteries BAT ₁ , BAT ₂ ,..., BAT _{K in} the order of Ch-1, Ch-2,. The pre-voltage adjustment described in the first embodiment (steps S101 and S102) is performed by controlling the scanner 540 such that the secondary battery BAT _k selected by each Ch is the voltage adjustment target. I do.

After all the pre-voltage adjustments are completed, the control unit 515 controls the secondary batteries BAT ₁ , BAT ₂ ,..., BAT _{K in} the order of Ch-1, Ch-2,. The scanner 540 is controlled so that each becomes a voltage adjustment target, and each secondary battery BAT _k selected by each Ch is set as a voltage adjustment target, and the processes of steps S103 (or S303) to S108 are executed.

When voltage adjustment is performed by the method of the first or second embodiment, the following control is performed (see FIG. 12).
(1) The voltage regulator 510 charges or discharges the secondary battery BAT _i [where i = 1,..., K−1] to be voltage regulated (charging or discharging in pre-voltage regulation or voltage precision regulation). after completion, after voltage recovery latency T _i for further stabilized open-circuit voltage value of the secondary battery BAT _i has elapsed, to obtain the open-circuit voltage value OCV _n of the secondary battery BAT _i. The execution in the scanner 540 of the present embodiment, the open circuit voltage measurements of the secondary battery BAT _i at a constant time interval for identifying the voltage return waiting time T _i, the other secondary battery BAT i + ₁ charge and discharge at the same time Can not. Therefore, the voltage recovery waiting time T ₁ (constant) obtained in advance is set as the voltage recovery waiting time T _i . In the example of FIG. 12, a constant voltage return waiting time T ₁ has elapsed after completion of the pre-voltage adjustment (t (i, 1) to t (i, 2)) for the secondary battery BAT _i (Ch-i). The open circuit voltage value at time t (i, 4) after time t (i, 3) is set as the open circuit voltage value OCV _n of the secondary battery BAT _i (Ch-i). The same applies to the voltage return waiting time after the voltage precision adjustment and the measurement timing of the open circuit voltage value OCV _n . As a result, accurate voltage adjustment by the inexpensive scanner 540 becomes possible.

(2) The voltage adjustment device 510, after completion of charging or discharging of the secondary battery BAT _i (charging or discharging in pre-voltage adjustment or precise voltage adjustment), before obtaining the open circuit voltage value OCV _n of the secondary battery BAT _i In addition, charging or discharging (charging or discharging in voltage precision adjustment) of the other secondary battery BAT _{i + 1} is started. Thereby, the voltage adjustment time as the whole battery pack 450 can be shortened.

[Modifications, etc.]
In addition, this invention is not limited to the above-mentioned embodiment. For example, the various processes described above are not only executed in time series according to the description, but may also be executed in parallel or individually as required by the processing capability of the apparatus that executes the processes. Needless to say, other modifications are possible without departing from the spirit of the present invention.

  When the configuration of the voltage regulator described above is realized by a computer, the processing contents of functions that the voltage regulator should have are described by a program. By executing this program on a computer, the above processing functions are realized on the computer. The program describing the processing contents can be recorded on a computer-readable recording medium. An example of a computer-readable recording medium is a non-transitory recording medium. Examples of such a recording medium are a magnetic recording device, an optical disk, a magneto-optical recording medium, a semiconductor memory, and the like.

  This program is distributed, for example, by selling, transferring, or lending a portable recording medium such as a DVD or CD-ROM in which the program is recorded. Furthermore, the program may be distributed by storing the program in a storage device of the server computer and transferring the program from the server computer to another computer via a network.

  A computer that executes such a program first stores, for example, a program recorded on a portable recording medium or a program transferred from a server computer in its own storage device. When executing the process, this computer reads a program stored in its own recording device and executes a process according to the read program.

  Alternatively, at least a part of the configuration of the voltage adjustment device may be configured only by hardware.

1-5 Voltage adjustment system 110-510 Voltage adjustment device 120 Voltage measurement device 130,230 Current generator

Claims (14)

1st to N voltage precise adjustment steps [N is a positive integer],
The nth voltage precision adjustment step [n = 1,...
This is an estimated value of charge that should be charged or discharged in order for the open circuit voltage value of the secondary battery to reach the target voltage value finalV after measuring the secondary battery to be voltage adjusted to obtain the open circuit voltage value OCV _n. An _n- th excess / deficiency capacity obtaining step for obtaining excess / deficiency capacity targ_n;
An nth charge / discharge start step for starting charging or discharging of the secondary battery;
An _n- th charge / discharge end step for ending charge or discharge of the secondary battery when the estimated value of the charged or discharged charge after the n-th charge / discharge start step reaches the excess / deficient capacity targQ _n , A voltage adjustment method characterized by comprising. The voltage adjustment method of claim 1,
A pre-voltage adjustment step executed before the first to N voltage precision adjustment steps;
The pre-voltage adjustment step includes
A pre-charge / discharge start step of starting charging or discharging of the secondary battery after measuring the secondary battery and obtaining an open circuit voltage value OCV ₀ ;
The open circuit voltage value OCV ₀ is obtained from the closed circuit voltage V ₀ obtained by measuring the secondary battery at a starting time of charging or discharging of the secondary battery or at a certain time after the starting time, and a target voltage value finalV. A charge / discharge end voltage value acquisition step of adding a subtraction value ΔV ₀ obtained by subtraction to obtain a charge / discharge end voltage value targV;
A pre-charge / discharge end step of ending charging or discharging of the secondary battery when the closed circuit voltage of the secondary battery reaches the charge / discharge end voltage value targV. The voltage adjustment method according to claim 2,
The pre-voltage adjusting step further includes a pre-capacitance obtaining step of obtaining a capacity Q ₀ that is an estimated value of the charge or discharge charged or discharged between the pre-charge / discharge start step and the pre-charge / discharge end step,
The n-th voltage precise adjustment step includes an n-th capacity acquisition step of obtaining a capacity Q _n that is an estimated value of a charge charged or discharged between the n-th charge / discharge start step and the n-th charge / discharge end step. In addition,
The n-th excess / deficiency capacity acquisition step includes finalV, Q _n−1 , OCV _n and OCV _n−1.
Obtaining the excess / deficiency capacity targQ _n corresponding to
The voltage adjustment method characterized by the above-mentioned. The voltage adjustment method according to claim 3,
The excess / deficiency capacity targQ _n satisfies targQ _n = Q _n−1 × (finalV−OCV _n ) / (OCV _n −OCV _n−1 ),
The voltage adjustment method characterized by the above-mentioned. The voltage adjustment method according to any one of claims 2 to 4,
The charging / discharging end voltage value obtaining step determines a value equal to or less than the threshold value when the added value of the closed circuit voltage V ₀ and the subtraction value ΔV ₀ exceeds a predetermined threshold value. including the step of setting targetV,
The voltage adjustment method characterized by the above-mentioned. The voltage adjustment method according to any one of claims 2 to 5,
The pre-charge and discharge start step, the subtraction value [Delta] V ₀ is the charge of the secondary battery starts when positive, is a step in which the subtraction value [Delta] V ₀ starts to discharge of the secondary battery for negative ,
The voltage adjustment method characterized by the above-mentioned. The voltage adjustment method according to any one of claims 1 to 6,
The n-th charge / discharge start step starts charging the secondary battery when a subtraction value ΔV _n obtained by subtracting the open circuit voltage value OCV _n from the target voltage value finalV is positive, and the subtraction value ΔV starting discharge of the secondary battery when _n is negative,
The voltage adjustment method characterized by the above-mentioned. The voltage adjustment method according to any one of claims 1 to 7,
The open circuit voltage value OCV _n is measured after the secondary battery is charged or discharged, and after a voltage return waiting time for stabilizing the open circuit voltage value of the secondary battery has elapsed. Is the value obtained by
The voltage adjustment method characterized by the above-mentioned. The voltage adjustment method according to any one of claims 1 to 7,
The open circuit voltage value OCV _n is obtained by using the open circuit voltage value of the secondary battery measured at a plurality of time points after completion of charging or discharging of the secondary battery, and the open circuit voltage of the secondary battery after voltage stabilization Voltage estimate,
The voltage adjustment method characterized by the above-mentioned. The voltage adjustment method according to any one of claims 1 to 9,
The resulting open circuit voltage value OCV _n of the secondary battery further comprises a second n determination step of determining whether the open circuit voltage value OCV _n has reached the target voltage value FinalV,
If it is not determined that the open circuit voltage value OCV _n has reached the target voltage value finalV in the nth determination step, the nth voltage precision adjustment step is performed;
After the nth voltage precision adjustment step, n + 1 is set as a new n, and the nth determination step is executed.
The voltage adjustment method characterized by the above-mentioned. The voltage adjustment method according to any one of claims 1 to 10,
Voltage adjustment of each of _K secondary batteries BAT _k [where k = 1,..., K] selected from _K secondary batteries BAT ₁ ,. Target
After the charging or discharging of the secondary battery BAT _i [where i = 1,..., K−1] subject to voltage adjustment, the voltage return for further stabilizing the open circuit voltage value of the secondary battery BAT _i After the waiting time T _i has elapsed, the open circuit voltage value OCV _n of the secondary battery BAT _i is obtained,
After completion of the charging or discharging of the secondary battery BAT _i, prior to obtaining the open circuit voltage value OCV _n of the secondary battery BAT _i, starts charging or discharging of the secondary battery _{BAT i + 1,}
The voltage adjustment method characterized by the above-mentioned.   A voltage regulator for executing the voltage regulation method according to claim 1. The voltage regulator of claim 12;
A current generator and a voltage measuring device connected to the voltage regulator;
A scanner connected to the voltage regulator, the current generator and the voltage measuring device;
The voltage regulator is selected, the secondary battery _BAT 1 of K [where K is an integer greater than one], ..., secondary batteries BAT _K BAT _k [However k = 1, ..., K] and And
The scanner connects the current generating device and the voltage measuring device to the selected secondary battery BAT _k ,
The voltage regulator is
Executing the voltage adjustment method using the secondary battery BAT _k connected to the current generator and the voltage measuring device as the voltage adjustment target;
After the charging or discharging of the secondary battery BAT _i [where i = 1,..., K−1] subject to voltage adjustment, the voltage return for further stabilizing the open circuit voltage value of the secondary battery BAT _i After the waiting time T _i has elapsed, the open circuit voltage value OCV _n of the secondary battery BAT _i is obtained,
After completion of the charging or discharging of the secondary battery BAT _i, prior to obtaining the open circuit voltage value OCV _n of the secondary battery BAT _i, starts charging or discharging of the secondary battery _{BAT i + 1,}
A voltage regulation system characterized by that.   The program for making a computer perform each step of the voltage adjustment method in any one of Claim 1 to 11.

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