Method for controlling charging and discharging of secondary battery

Abstract

The purpose of the present invention is to provide a method for controlling the charge and discharge of a secondary battery, in which the range of use of an SOC is quickly corrected on the basis of an SOC estimation error using a simple method, and the charge and discharge are safely and efficiently controlled. A control device estimates an estimated voltage VE [V] on the basis of a measured current AM [A], a measured voltage VM [V], and a measured temperature TM [DEG C] of a lithium ion secondary battery (S1) (S2), collects a sample for calculating an estimation error E [%] of SOC (S5), and calculates an upper limit error EH [%] and a lower limit error EL [%] (S8). Then, the upper limit LH of the used SOC is reset on the basis of the upper limit error EH [%], and the lower limit LL of the used SOC is reset on the basis of the lower limit error EL (S10). The charge / discharge of the lithium ion secondary battery is then controlled on the basis of the corrected usable SOC range.

Description

Technical Field

[0001] The present invention relates to a method for controlling charging and discharging of a secondary battery. More specifically, it relates to a method for controlling charging and discharging of a secondary battery that safely and effectively controls the SOC usage range based on the SOC estimation error. Background Art

[0002] In secondary batteries, especially in driving secondary batteries mounted on electric vehicles and hybrid vehicles, large currents are used for charging and discharging during rapid acceleration, regenerative current based on braking, rapid charging, etc. For such charging and discharging, in order to avoid over-discharging and over-charging, control is performed to limit the usage range of SOC (state of charge, charge rate). For example, the upper limit value used is set to 80 [%], the lower limit value is set to 20 [%], and the charging and discharging are controlled so that the SOC always falls within this range.

[0003] For example, in the invention described in Patent Document 1, an invention is described in which the charge and discharge rate is limited by SOC. However, when there is an error in the calculation of SOC, the suitable SOC range also changes, but in the invention described in Patent Document 1, the SOC usage range itself is not corrected.

[0004] Regarding such control, in order to perform control more safely and effectively, the following inventions have been proposed. For example, in the invention described in Patent Document 2, the SOC obtained based on the current cumulative value is taken as the true value, and the error of the estimated SOC relative thereto is calculated. Thereby, the upper and lower limits of SOC are corrected. With such an invention, more appropriate control can be performed.

[0005] In the invention described in Patent Document 3, the parameters of the battery model are obtained through a neural network. Thereafter, the parameters of the battery model are repeatedly updated based on the difference between the output value of the battery model reflecting the obtained parameters and the actual measurement value. Thereby, a battery model most suitable for the battery cell can be constructed, and the charging of the battery can be controlled based on the most suitable battery model. With such an invention, more appropriate control can be performed. Prior Art Documents Patent Documents

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2011-041436 Patent Document 2: Japanese Unexamined Patent Application Publication No. 2015-197428 Patent Document 3: Japanese Unexamined Patent Application Publication No. 2022-502815 Summary of the Invention Problems to be Solved by the Invention

[0007] However, in the invention described in Patent Document 2, since the current integrated value is used as the true value of the SOC estimation, it takes time to obtain the error. In addition, the current integrated value has the problem that the current measurement itself has an error and is easily affected by the accumulation of errors when it is obtained for a long time.

[0008] In addition, the invention described in Patent Document 3 has a problem that the battery model and the limitation cannot be separated because the battery model itself is updated each time regarding the correction method. In addition, since the battery is not corrected for the model immediately after it is used, it is not possible to use the battery in a way that takes the error into consideration.

[0009] An object of the method for controlling charge and discharge of a secondary battery of the present invention is to quickly correct the SOC use range based on the SOC estimation error by a simple method, thereby controlling charge and discharge safely and efficiently. Means for solving problems

[0010] One aspect of the present disclosure is a method for controlling the charge and discharge of a secondary battery using a control device, the control method comprising the following steps: an information acquisition step of acquiring a measured current A obtained by measuring the secondary battery. M [A], Measurement voltage V M [V], Measurement temperature T M [℃]; a battery voltage estimation step, based on the measured current A obtained in the above information acquisition step M [A], Measurement temperature T M [℃] information, and estimate the estimated voltage V E [V]; Sample collection step, measuring voltage V for calculating estimated error E of SOC when current I flows through the secondary battery under certain conditions M [V] and estimated voltage V E [V]; a sample classification step, based on a reference value S[%] based on a pre-set common SOC center, classifying the above-mentioned multiple samples collected in the above-mentioned sample collection step, and classifying them as upper limit side judgment samples SP H , or the lower limit judgment sample SP L ; SOC estimation error calculation step, based on the upper limit side judgment sample SP gathered more than a certain number of H , calculate the available SOC range S U The upper limit L H The estimation error E is the upper limit error E H [%], based on the fact that a certain number or more of the lower limit judgment samples SP have been gathered L , calculate the above usable SOC range SU Lower limit L L Estimation error E of, i.e., lower limit error E L [%]; and upper and lower limit SOC re - setting steps. In order to control the available SOC range S of the above - mentioned secondary battery U , according to the above - mentioned upper limit error E H [%] re - set the above - mentioned available SOC range S U Upper limit L H , according to the above - mentioned lower limit error E L Re - set the above - mentioned available SOC range S U Lower limit L L .

[0011] The above - mentioned control method can further include protection processing steps for the upper and lower limits. Based on the re - set available SOC range S U Upper limit L H And lower limit L L , implement protection processing for optimizing the above - mentioned available SOC range S U .

[0012] In the above - mentioned control method, the protection processing steps for the upper and lower limits can be based on the above - mentioned upper limit L H And the above - mentioned lower limit L L Of the above - mentioned available SOC range S U In a manner of 20% or more to control the re - setting of the above - mentioned upper limit L H And the above - mentioned lower limit L L .

[0013] In the above - mentioned control method, in the protection processing steps for the upper and lower limits, according to the above - mentioned upper limit error E H The re - set upper limit L H Set within the range of the maximum difference ΔMax and the minimum difference ΔMin of the above - mentioned upper limit error E H , according to the above - mentioned lower limit error E L The re - set lower limit L L Set within the range of the maximum difference ΔMax and the minimum difference ΔMin of the above - mentioned lower limit error E L .

[0014] In the above - mentioned control method, in the above - mentioned battery voltage estimation step, the estimated voltage can be estimated as the closed - circuit voltage of the above - mentioned secondary battery, i.e., voltage V E [V].

[0015] The above - mentioned control method can further include a battery model correction step, comparing the measured voltage V M [V] with the estimated voltage V E[V] is compared to calibrate the above battery model.

[0016] In the above control method, during the above measurement of voltage V M [V] and the above estimated voltage V E [V], when the difference ΔV[V] is above the threshold Th, the above battery model calibration step is executed. In the above control method, in the above sample classification step, the reference value S based on the preset common SOC center, which classifies the above multiple collected samples into upper limit side judgment samples or lower limit side judgment samples, can be set to a value of SOC40 [%] or more and SOC60 [%] or less.

[0017] In the above control method, in the above SOC estimation error calculation step, the estimation error of SOC is set as E [%], the number of samples collected is set as N, the number of times of sample collection is set as k, the measured voltage is set as V M [V], the estimated voltage is set as V E [V], and when the voltage corresponding to 1 [%] of the SOC of the above secondary battery is set as V1[V], The estimation error E [%] can be calculated by the following formula. [Equation 1]

[0018] In the above control method, the above secondary battery is a power source for vehicle drive, and the above control device can be mounted on a vehicle. In the above control method, the above secondary battery can be a lithium-ion secondary battery. Advantages of the Invention

[0019] According to the charge and discharge control method of the secondary battery of the present invention, the SOC usage range can be quickly calibrated according to the SOC estimation error by a simple method, and the charge and discharge can be controlled safely and effectively. Description of the Drawings

[0020] Figure 1 It is a diagram for explaining the control of SOC of this embodiment. Figure 2 It is a diagram showing the equivalent circuit of the battery model of the lithium-ion secondary battery of this embodiment. Figure 3 It is a perspective view showing the appearance of the lithium-ion secondary battery of this embodiment. Figure 4 It is a schematic diagram showing the electrode body of the lithium-ion secondary battery of this embodiment. Figure 5It is a block diagram showing an example of the configuration of a vehicle using a lithium-ion secondary battery in the implementation stage. Figure 6 It is a block diagram showing the details of the configuration of the memory of the ECU of the full charge capacity estimation device of the present embodiment. Figure 7 It is a flowchart showing the process of the charge and discharge control method of the lithium-ion secondary battery of the present embodiment. Detailed implementation mode

[0021] (Outline of the present embodiment) The following is referred to Figures 1 to 7 The charge and discharge control method of the secondary battery of the present invention will be described by an example of the charge and discharge control method of the lithium-ion secondary battery 1.

[0022] <Principle of the invention of the present embodiment> In the charge and discharge control method of the lithium-ion secondary battery 1 of the present embodiment, the SOC usage range is corrected quickly according to the SOC estimation error by a simple method, and the charge and discharge are controlled safely and effectively. As described in the background art, conventionally, as in the invention described in Patent Document 2, since the current integration is taken as the true value of the SOC estimation, there is a problem that it takes time to obtain the error. In addition, regarding the current integration value, there are problems that the measurement of the current itself has an error and it is easily affected by the accumulation of errors when obtained for a long time. In addition, as in the invention described in Patent Document 3, regarding the correction method, since the battery model itself is updated every time, there is a problem that the battery model cannot be separated from the limit. In addition, since the model correction has not been performed after the battery has just been used, there is a problem that a usage method considering the error cannot be performed.

[0023] Therefore, in the charge and discharge control method of the lithium-ion secondary battery 1 of the present embodiment, by performing the SOC estimation based on voltage, which has less measurement error than the SOC estimation based on current integration and has a short measurement time, the SOC error can be detected quickly and in real time. In addition, by appropriately correcting the battery model, the accuracy of the SOC estimation can be improved by use. By detecting the SOC error quickly and accurately like this, even for a battery with a usage history, deterioration can be suppressed by setting an appropriate SOC usage range, and the performance of the battery can be fully exhibited.

[0024] <Estimation of SOC [%] of the present embodiment> Figure 1It is a diagram for explaining the control of the SOC of the present embodiment. In the lithium-ion secondary battery 1 of the present embodiment, SOC0 [%] to SOC100 [%] are set in the initial stage, and a battery model of the lithium-ion secondary battery 1 designed in this way is assumed.

[0025] Figure 2 It is a diagram showing the equivalent circuit of the battery model of the lithium-ion secondary battery 1 of the present embodiment. In the lithium-ion secondary battery 1, as Figure 2 shown, the equivalent circuit can be shown by a parallel circuit of a resistor (impedance) R0 and a resistor R1 and a capacitor C1 connected in series therewith. In such an equivalent circuit, for example, the values of the resistor R0, the resistor R1, and the capacitor C1 can be determined by complex AC impedance measurement. And the combined resistance of the entire equivalent circuit can be obtained. There are various factors in the state change of the actual lithium-ion secondary battery 1. For example, there are not only an increase in internal resistance due to the formation of a coating film such as SEI (Solid Electrolyte Interphase) on the negative electrode, decomposition of the non-aqueous electrolyte, self-discharge due to a micro short circuit, but also factors such as temporary ion bias. However, in order to perform simple SOC prediction, they are simplified, and an equivalent circuit based on the resistors (impedances) R0, R1, and the capacitor (capacitance) C1 can be used to represent it. Such a battery model can be used to estimate the estimated voltage V M [A] and the measured temperature T M [°C] information, and estimate the estimated voltage V E [V]. It should be noted that since the internal resistance changes according to the temperature, correction based on the temperature is required. It should be noted that the battery model is not constant, and correction based on deterioration is required.

[0026] Next, in the battery model configured in this way, the SOC [%] can be estimated based on the open-circuit battery voltage OCV (open-circuit voltage). However, in the present embodiment, the voltage between the two terminals of the battery is measured in a state where the battery is connected to the device and current flows, so the closed-circuit voltage CCV (Closed circuit voltage) is measured. Since the battery has an internal resistance, the closed-circuit voltage shows a value smaller than the circuit voltage, and the larger the flowing current, the smaller the closed-circuit voltage. Therefore, the voltage [V] corresponding to the SOC [%] is measured in advance by measuring the same type of lithium-ion secondary battery 1. And if a conversion table is made based on their relationship, the SOC [%] can be immediately estimated according to the measured voltage V M [V].

[0027] On the other hand, in the current integration method, the SOC [%] of the lithium-ion secondary battery 1 can be estimated by integrating the current I [A]. That is, the current SOC [%] can be estimated by the ratio of the integral value of ∫Idt [Wh] to the FCC (Full Charge Capacity) [Wh].

[0028] In the present embodiment, such a battery model is used to estimate the SOC [%]. <The available SOC range S can be used U > As Figure 1 shown, in the SOC [%] based on the unused battery, the upper limit L H0 [%] of the initial setting for normal use is determined. In the present embodiment, it is set to 80 [%] for example. This is the margin used to prevent overcharging even during regenerative current such as on a long downhill slope. On the other hand, the lower limit L L0 [%] of the initial setting for normal use is determined. In the present embodiment, it is set to 20 [%] for example. This is the margin used to prevent overdischarge even during large discharges based on driving power such as on a long uphill slope.

[0029] The range sandwiched between such an upper limit L H0 and a lower limit L L0 is the available SOC range S U [%], which is in the range of 20 [%] or more and 80 [%] or less in the present embodiment. However, in the lithium-ion secondary battery 1 etc. where the usage history is unclear, there are cases where the battery capacity decreases or the internal resistance increases due to the progression of deterioration. In such cases, even when the measured voltage V M [V] is the same, or when the measured current A M [W] is the same, there may be errors in the estimated SOC [%] based on these.

[0030] <Information acquisition step / Battery voltage estimation step> In the present embodiment, the SOC [%] is estimated based on the battery model. Here, the measured voltage V M [V] of the lithium-ion secondary battery 1 is actually obtained. In addition, at the same time point, the estimated voltage V E [V] based on the battery model is calculated. And the difference ΔV [V] between the measured voltage V M [V] and the estimated voltage V E [V] is calculated. This difference ΔV [V] can be said to be caused by the deterioration of the battery model from the initial stage. Therefore, based on this ΔV [V], the estimation error E [%] of the SOC [%] is obtained.

[0031] <Sample collection step / Sample classification step> Here, the "sample" is a sample for calculating the estimation error E [%], specifically, a sample of the difference ΔV [V] between the measured voltage V M [V] and the estimated voltage V E [V]. Based on this measured voltage V M [V] and the estimated voltage V E [V], the error of SOC is estimated from the difference ΔV [V]. In this sample collection step, under certain conditions, a current I (measurement current A M ) is passed through the lithium-ion secondary battery 1, and the sample for calculating the estimation error E of SOC is used. Here, regarding the "certain conditions", for example, the measurement current A M is limited in such a way that the power [W] is 1000 [W] or more and the duration is 5 [seconds]. This is to make it data meaningful for estimating the SOC error.

[0032] In addition, for the multiple samples collected, they are classified based on a reference value S with a preset common SOC center as the reference. The reference value S is set to a value of 40 [%] or more and 60 [%] or less of SOC. The reason is that, roughly bounded by SOC of 40 - 60 [%], the behavior is different in the high SOC region and the low SOC region. In this embodiment, the reference value S is set to 50 [%]. For example, if the sample is the measured voltage V M [V] = 4.000 [V], then the SOC at this time is estimated to be 50% or more. Since it exceeds the reference value S, this sample is collected as an upper limit side determination sample SP H . On the other hand, if the sample is the measured voltage V M [V] = 3.500 [V], then the SOC at this time is estimated to be 50% or less. Since it is lower than the reference value S, this sample is collected as a lower limit side determination sample SP L .

[0033] In this way, multiple samples are collected and classified into an upper limit side determination sample SP H and a lower limit side determination sample SP L , and stored in the memory 102 ( Figure 5 ) of the control device 18. In the SOC estimation error calculation step, the upper limit error E H [%] based on the upper limit side determination samples Sam H aggregated with a certain number or more and the lower limit error E L based on the lower limit side determination samples Sam L [%] are calculated. That is, the upper limit error E H ​​​​​​​​​​​​​​​​​[%] is the estimation error E[%] with respect to the upper limit L H and the lower limit error E L [%] is the estimation error E[%] with respect to the lower limit L L . In the following description, sometimes the upper limit error E H [%] and the lower limit error E L [%] are collectively referred to as the estimation error E[%].

[0034] <SOC Estimation Error Calculation Steps> The estimation error E[%] of the SOC in this embodiment is calculated by the following formula. It is divided into the upper limit side determination sample SP H and the lower limit side determination sample SP L and the calculation of the estimation error E[%] is performed separately. The upper limit side determination sample SP H and the lower limit side determination sample SP L are respectively collected in a predetermined number of samples. For example, in this embodiment, 10 samples are collected. After that, for the collected upper limit side determination sample SP H and the lower limit side determination sample SP L , the calculation of the estimation error E[%], that is, the upper limit error E H and the lower limit error E L [%] is performed respectively.

[0035] Here, when the estimation error is set as E%, the number of samples is set as N, the number of sample collection times is set as k, the measured voltage is set as V M [V], the estimated voltage is set as V E [V], and the voltage corresponding to 1[%] of the SOC of the secondary battery is set as V1[V], it is obtained by the following formula 1.

[0036] [Equation 2]

[0037] Here, the voltage V1[V] corresponding to 1[%] of the SOC of the secondary battery is calculated as follows. For example, the voltage of SOC 100[%] is set as 4.2[V], and the voltage of SOC 0[%] is set as 3.0[V]. Then, when there is a difference in SOC 100%, the voltage difference V1[V] is 4.2 - 3.0 = 1.2[V]. If it is divided by 100, the voltage of V1[V] corresponding to SOC 1[%] is approximately 0.012[V] (12[mV]).

[0038] Next, the measured voltage V H obtained in the upper limit side determination sample SP M [V] is 4.000[V]. In addition, the calculated estimated voltage V E [V] is 4.100[V].

[0039] Thus, V M -V E = 4.000 - 4.100 = -0.100 [V]. And, the absolute value of (V M -V E ) │V M -V E │ = 0.100. In this way, when the obtained │V M -V E │ is divided by V1, 0.100 ÷ 0.012 = 8.3. If it is expressed as a percentage [%], it is 8.3 [%].

[0040] In this embodiment, using 10 upper-limit determination samples SP H the estimation error E [%] is repeatedly obtained, and the upper-limit error E H [%] is calculated using its arithmetic mean. Here, the upper-limit error E H [%] = 8.3 [%].

[0041] <Upper and lower limit SOC re-setting step> In the upper and lower limit SOC re-setting step, based on the upper-limit error E H [%], the upper limit L H of the SOC used is re-set, and based on the lower-limit error E L the lower limit L L of the SOC used is re-set.

[0042] As Figure 1 shown, the initially set upper limit L H0 [%] is SOC = 80 [%]. However, if charging and discharging are controlled using the initially set upper limit L H0 [%] of SOC = 80 [%], the battery capacity [Ah] may decrease due to battery degradation, etc., and actually the SOC [%] may be higher.

[0043] Therefore, based on the upper-limit error E H [%] calculated in the SOC estimation error calculation step, the initially set upper limit L H0 [%] is changed to the corrected upper limit L HR [%]. Similarly, based on the lower-limit error E L [%] calculated in the SOC estimation error calculation step, the initially set lower limit L L0 [%] is changed to the corrected lower limit L LR [%]. Then, the initially available SOC range S U0 [%] is set as the corrected available SOC range S U1 [%]. In this embodiment, the initially available SOC range SU0 = 80 - 20 = 60 [%] is set as the available SOC range S after correction U1 [%] = (80 - 8.3) - (20 + 8.3) = 43.4 [%].

[0044] <Upper and lower limit protection processing steps> In the upper and lower limit protection (guard) processing steps, protection processing is implemented. In the upper and lower limit SOC re - setting step, re - setting is performed based on the estimation error E [%]. Here, based on the upper limit L of the used SOC H , the lower limit L of the used SOC L the available SOC range S U is optimized. "Optimization" is a process for ensuring the range of the available SOC range S U1 [%]. That is, this is because, when the estimation error E [%] is too large, the actually available corrected available SOC range S U1 [%] may become significantly narrower.

[0045] Here, "the upper limit L H1 = L H0 -(the minimum difference ΔMin ≤ the upper limit error E H ≤ the maximum difference ΔMax)… Equation 2" is the equation for calculating the upper limit L in the protection processing of this embodiment H . "The lower limit L L1 = L L0 +(the minimum difference ΔMin ≤ the lower limit error E L ≤ the maximum difference ΔMax)… Equation 3" is the equation for calculating the lower limit L in the protection processing of this embodiment L .

[0046] Here, (the minimum difference ΔMin ≤ the upper limit error E H ≤ the maximum difference ΔMax) is the concept that the upper limit error E H is limited within the range of the minimum difference ΔMin ≤ the upper limit error E H ≤ the maximum difference ΔMax. For example, the minimum difference ΔMin [%] = 0 [%], and the maximum difference ΔMax = 20 [%].

[0047] In this case, as described above, if the upper limit error EH [%] is 8.3 [%], it is within the range of the minimum difference ΔMin ≤ the upper limit error E H ≤ the maximum difference ΔMax, so no protection processing is performed. Here, the measured voltage V H obtained in the upper - limit - side determination sample SP M [V] is 4.011 [V]. In addition, the calculated estimated voltage VE [V] is 4.001 [V]. Thus, the upper limit error E obtained from Equation 1 H = 83 [%]. If this upper limit error E H = 83 [%] is substituted into Equation 2, it is greater than the maximum difference ΔMax = 20 [%], so the upper limit error E is limited to H = 20 [%].

[0048] Therefore, if the "upper limit L H1 = L H0 -(minimum difference ΔMin ≤ upper limit error E H ≤ maximum difference ΔMax) … Equation 2" is applied, then the upper limit L H1 = L H0 -(minimum difference ΔMin ≤ upper limit error E H ≤ maximum difference ΔMax) = 80 - (20) = 60, and the upper limit L H1 is not less than 60 [%].

[0049] Similarly, for the lower limit L L1 [%], the "lower limit L L1 = L L0 +(minimum difference ΔMin ≤ lower limit error E L ≤ maximum difference ΔMax) … Equation 3" is applied. Here, the minimum difference ΔMin [%] is also set to 0 [%] and the maximum difference ΔMax = 20 [%].

[0050] For the measurement voltage V L obtained from the sample SP M for lower limit side determination, it is 3.510 [V]. Additionally, the estimated voltage V E [V] calculated is 3.500 [V]. Thus, the lower limit error E obtained from Equation 1 L = 83 [%]. If this lower limit error E L = 83 [%] is substituted into Equation 2, it is greater than the maximum difference ΔMax = 20 [%], so the lower limit error E is limited to L = 20 [%].

[0051] Therefore, if the "lower limit L L1 = L L0 +(minimum difference ΔMin ≤ lower limit error E L ≤ maximum difference ΔMax) … Equation 3" is applied, then the lower limit L L1 = L L0 +(minimum difference ΔMin ≤ lower limit error E L ≤ maximum difference ΔMax) = 20 + (20) = 40, and the lower limit LL1 Not higher than 40 [%].

[0052] <Optimization of the corrected available SOC range S U1 > In the protection processing step of the upper and lower limits, according to the upper limit error E H [%] Set upper limit L H [%] Set in the upper limit error E H Range of the maximum difference ΔMax and the minimum difference ΔMin. Additionally, according to the lower limit error E L [%] Set lower limit L L [%] Set in the lower limit error E L Range of the maximum difference ΔMax and the minimum difference ΔMin. In this case, apply "corrected available SOC range S U1 = Available SOC range S in the initial setting U0 -(Maximum difference ΔMax of the upper limit error E H + Maximum difference ΔMax of the lower limit error E L )... Equation 4". The available SOC range S in the initial setting U Is set to 60 [%], at least assuming that the available SOC range S U Needs to be 20 [%] in an actual vehicle. In this case, set it to "corrected available SOC range S U1 = Available SOC range S in the initial setting U0 60 [%]-(Maximum difference ΔMax of the upper limit error E H + Maximum difference ΔMax of the lower limit error E L ) ≥ 20 [%])... Equation 4". Thus, it is possible to make the corrected available SOC range S U1 [%] 20 [%] or more. That is, by setting (maximum difference ΔMax of the upper limit error E H的 + Maximum difference ΔMax of the lower limit error E L ) ≤ 40 [%], it is possible to ensure that the corrected available SOC range S U1 Is 20 [%] or more.

[0053] <Battery model correction step> In this embodiment, when the difference ΔV [V] between the measured voltage V M [V] and the estimated voltage V E [V] is equal to or greater than the threshold Th, the battery model correction step is executed. In the battery model correction step, by Figure 2 Re-evaluating the resistance R0, R1, capacitance C1, etc. of the battery model shown, the measured voltage V M [V] and the estimated voltage V EThe threshold Th of the difference ΔV [V] is defined by the voltage value [V]. Alternatively, the threshold Th can also be defined by the ratio of the measured voltage V M [V] to the estimated voltage V E .

[0054] Alternatively, the battery model correction step can also be executed at other opportunities for a certain usage time, etc. (Configuration of this embodiment) <Configuration of the lithium-ion secondary battery 1 Figure 3 is a perspective view showing an outline of the external configuration of the lithium-ion secondary battery 1 of this embodiment. First, the configuration of the lithium-ion secondary battery 1 of this embodiment, which is an example of the present invention, will be described.

[0055] Figure 3 The lithium-ion secondary battery 1 shown is a single cell, and a battery module 1M is composed of single cells (refer to Figure 5 ). The lithium-ion secondary battery 1 as a single cell has a plate-shaped rectangular parallelepiped battery case 11 with an opening on the upper side. An electrode body 12 is housed inside the battery case 11. A non-aqueous electrolyte 13 is filled into the battery case 11 through a liquid injection hole. The battery case 11 is made of a metal such as aluminum alloy and forms an electrolytic cell sealed with a lid. In addition, the lithium-ion secondary battery 1 has a positive electrode external terminal 14 and a negative electrode external terminal 15 for charging and discharging electric power. The positive electrode external terminal 14 is electrically connected to the positive electrode current collector terminal 16 inside the battery case 11 via the lid. In addition, the negative electrode external terminal 15 is electrically connected to the negative electrode current collector terminal 17 inside the battery case 11 via the lid. The positive electrode current collector terminal 16 is electrically connected to the positive electrode current collector portion 33 of the electrode body 12 (refer to Figure 4 ). In addition, the negative electrode current collector terminal 17 is electrically connected to the negative electrode current collector portion 23 of the electrode body 12 (refer to Figure 4 ).

[0056] <Electrode body 12 Figure 4 is a schematic diagram showing the configuration of the wound electrode body 12. The electrode body 12 is formed by laminating a plurality of negative electrode plates 2, positive electrode plates 3, and separators 4 disposed between them. The laminated negative electrode plates 2, positive electrode plates 3, and separators 4 are wound to form a flat shape. In the negative electrode plate 2, a negative electrode composite material layer 22 is formed on a negative electrode current collector 21 made of copper foil as a base material. A negative electrode current collector portion 23 is provided on one end side in the width direction W (winding axis direction) orthogonal to the winding direction L. The negative electrode current collector portion 23 is configured such that the negative electrode current collector 21 is exposed without forming the negative electrode composite material layer 22.

[0057] In the positive electrode plate 3, a positive electrode composite material layer 32 is formed on a positive electrode current collector 31 made of aluminum foil as a base material. AsFigure 4 As shown, a positive current collector portion 33 is provided on the other end side (the side opposite to the negative current collector portion 23) in the width direction W (the winding axis direction) orthogonal to the winding direction L (the direction in which the positive current collector 31 is wound). The positive current collector portion 33 does not form a positive composite material layer 32, and the metal of the positive current collector 31 is exposed.

[0058] <Laminated Structure of Electrode Body 12> As Figure 4 shown, the basic configuration of the electrode body 12 of the lithium ion secondary battery 1 includes a negative electrode plate 2, a positive electrode plate 3, and a separator 4.

[0059] The negative electrode plate 2 has negative composite material layers 22 on both sides of a negative current collector 21 as a negative electrode substrate. One end portion of the negative current collector 21 becomes a negative current collector portion 23 where the metal is exposed. The positive electrode plate 3 has positive composite material layers 32 on both sides of a positive current collector 31 as a positive electrode substrate. The other end portion of the positive current collector 31 becomes a positive current collector portion 33 where the metal is exposed.

[0060] The negative electrode plate 2 and the positive electrode plate 3 are overlapped with each other with the separator 4 interposed therebetween to form a laminate. As Figure 4 shown, this laminate is wound around a winding axis in the length direction to form Figure 3 the wound-type electrode body 12 shaped into a flat shape as shown.

[0061] <Non-aqueous Electrolyte 13> Figure 3 The non-aqueous electrolyte 13 of the lithium ion secondary battery 1 of the present embodiment shown is impregnated in the electrode body 12. The non-aqueous electrolyte 13 is a composition in which a lithium salt is dissolved in an organic solvent. As the lithium salt, LiClO4, LiPF6, LiAsF6, LiBF4, LiSO3CF3, etc. can be used. As the organic solvent, cyclic carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate, and trifluoropropyl methyl carbonate, chain carbonates such as diethyl carbonate, dimethyl carbonate, methyl ethyl carbonate, and dipropyl carbonate, ether compounds such as tetrahydrofuran, 2-methyltetrahydrofuran, and dimethoxyethane, sulfur-containing compounds such as ethyl methyl sulfone and butane sultone, or phosphorus compounds such as triethyl phosphate and trioctyl phosphate can be cited. As the non-aqueous electrolyte 13, one or more of them can be mixed and used. It should be noted that the composition of the non-aqueous electrolyte 13 is not limited thereto.

[0062] <Constituent Elements of Electrode Body 12> Next, the negative electrode plate 2, the positive electrode plate 3, and the separator 4, which are the constituent elements of the electrode body 12, will be described.

[0063] <Negative Electrode Plate 2> As Figure 4As shown, a negative electrode plate 2 is formed by forming negative electrode composite material layers 22 on both sides of a negative electrode current collector 21 serving as a negative electrode base material. In the negative electrode composite material layer 22, a negative electrode composite material paste 22a is coated onto the negative electrode current collector 21. Subsequently, through a drying process, a pressing process, and a cutting process, the negative electrode plate 2 is completed.

[0064] <Negative electrode current collector 21> In this embodiment, the negative electrode current collector 21 is composed of a Cu foil. The negative electrode current collector 21 forms a base as an aggregate of the negative electrode composite material layer 22 and has a function of a current collecting component that collects electricity from the negative electrode composite material layer 22. One end portion of the negative electrode current collector 21 where the negative electrode composite material layer 22 is not formed becomes a negative electrode current collecting portion 23 where the metal surface is exposed. That is, the negative electrode active material particles are electrically connected to the negative electrode external terminal 15 via the negative electrode current collector 21, the negative electrode current collecting portion 23, and the negative electrode current collecting terminal 17.

[0065] <Negative electrode composite material layer 22> In this embodiment, the negative electrode active material is a powdery carbon material composed of graphite or the like having a layered structure and is a material capable of occluding and releasing lithium ions Li + +.

[0066] <Positive electrode plate 3> As Figure 4 shown, the positive electrode plate 3 is composed of a positive electrode current collector 31 serving as a positive electrode base material and a positive electrode composite material layer 32 coated onto the positive electrode current collector 31. In the positive electrode composite material layer 32, a positive electrode composite material paste is coated onto the positive electrode current collector 31. Subsequently, through a drying process, a pressing process, and a cutting process, the positive electrode plate 3 is completed.

[0067] <Positive electrode current collector 31> The positive electrode plate 3 is formed by forming positive electrode composite material layers 32 on both sides of a positive electrode current collector 31 serving as a positive electrode base material. In the embodiment, the positive electrode current collector 31 is composed of an Al foil. The positive electrode current collector 31 forms a base as an aggregate of the positive electrode composite material layer 32 and has a function of a current collecting component that collects electricity from the positive electrode composite material layer 32.

[0068] First, regarding the positive electrode base material constituting the positive electrode current collector 31, an Al foil is exemplified. For example, it is composed of a conductive material (formed of a metal with good conductivity). As a material with good conductivity, for example, in addition to the Al foil, a material containing an Al alloy can also be used. The configuration of the positive electrode current collector 31 is not limited thereto.

[0069] <Positive electrode composite material layer 32> The positive electrode composite material layer 32 is formed by applying a positive electrode composite material paste onto the positive electrode current collector 31 and drying it. The positive electrode composite material layer 32 contains, in addition to positive electrode active material particles, additives such as a conductive auxiliary material, a binder, and a dispersant.

[0070] <Composition of the positive electrode active material> The positive electrode active material particles contain a layered crystal structure-containing lithium transition metal oxide. The lithium transition metal oxide contains, in addition to Li, one or more predetermined transition metal elements. The transition metal element contained in the lithium transition metal oxide is preferably at least one of Ni, Co, and Mn. The positive electrode active material of the present embodiment may exemplify a ternary system material called so-called NCM having a lithium transition metal oxide containing all elements of Ni, Co, and Mn.

[0071] It should be noted that the positive electrode active material of the present embodiment is not limited to a material having a lithium transition metal oxide containing all elements of Ni, Co, and Mn. In addition, a composition containing, for example, Al in addition to them may also be used. Further, the positive electrode active material may be LiMnO4, LiFePO4, or the like.

[0072] <Separator 4> The separator 4 is a non-woven fabric made of polypropylene or the like, which is a porous resin for holding the non-aqueous electrolyte 13 between the negative electrode plate 2 and the positive electrode plate 3 and has high insulation. In addition, as the separator 4, a porous polymer film such as a porous polyethylene film, a porous polyolefin film, and a porous polyvinyl chloride film, or a lithium ion or ion conductive polymer electrolyte film may be used alone or in combination.

[0073] <Overall configuration of a vehicle equipped with a secondary battery> Figure 5 It is a block diagram showing an example of the configuration of a vehicle using the lithium ion secondary battery 1 at the implementation stage. Figure 5 The exemplified vehicle is a hybrid vehicle. The vehicle includes a control device 18 that also functions as a charge / discharge control device for the lithium ion secondary battery 1, a power control unit (PCU: Power Control Unit) 30, motor generators 41, 42, an engine 50, a power distribution device 60, a drive shaft 70, and drive wheels 80. The control device 18 of the lithium ion secondary battery 1 of the present embodiment includes a battery module 10A, a monitoring unit 40, and an ECU (electronic control device: Electronic Control Unit) 100.

[0074] The engine 50 is an internal combustion engine that outputs power by converting the combustion energy generated when burning a mixture of air and fuel into the kinetic energy of moving parts such as pistons and rotors.

[0075] The power distribution device 60 includes, for example, a planetary gear mechanism (not shown) having three rotating shafts of a sun gear, a gear carrier, and a ring gear. The power distribution device 60 divides the power output from the engine 50 into the power for driving the motor generator 41 and the power for driving the drive wheels 80.

[0076] The motor generators 41 and 42 are respectively AC rotating motors, for example, three-phase AC synchronous motors in which permanent magnets (not shown) are embedded in the rotors. The motor generator 41 is mainly used as a generator driven by the engine 50 via the power distribution device 60. The electric power generated by the motor generator 41 is supplied to the motor generator 42 or the lithium-ion secondary battery 1 via the PCU 30.

[0077] The motor generator 42 mainly operates as a motor to drive the drive wheels 80. The motor generator 42 is driven by receiving at least one of the electric power from the lithium-ion secondary battery 1 and the generated electric power of the motor generator 41, and the driving force of the motor generator 42 is transmitted to the drive shaft 70. On the other hand, during braking of the vehicle or when the acceleration on a downhill slope decreases, the motor generator 42 operates as a generator to perform regenerative power generation. The electric power generated by the motor generator 42 is supplied to the battery module 1M via the PCU 30.

[0078] The battery module 1M is composed of a plurality of lithium-ion secondary batteries 1 as single cells. The lithium-ion secondary battery 1 stores the electric power for driving the motor generators 41 and 42, and supplies electric power to the motor generators 41 and 42 through the PCU 30. In addition, during the power generation of the motor generators 41 and 42, the lithium-ion secondary battery 1 is charged by receiving the generated electric power through the PCU 30.

[0079] The monitoring unit 20 includes a voltage measuring device 40a, a current measuring device 40b, and a temperature measuring device 40c. The voltage measuring device 40a of the present embodiment detects, for example, the voltage E of each single cell of the lithium-ion secondary battery 1. However, it is also possible to detect the voltage E of the entire battery module 1M composed of a plurality of single cells (cells) of the lithium-ion secondary battery 1 connected in parallel with each other. In this case, the voltage of each single cell is estimated from the overall voltage. The current measuring device 40b detects the current I input and output in the lithium-ion secondary battery 1. The temperature measuring device 40c detects the temperature T of each block. Each measuring device outputs a signal indicating the detection result to the ECU 100.

[0080] It should be noted that the monitoring unit of the voltage measuring device 40a and the temperature measuring device 40c is substantially each single cell of the lithium-ion secondary battery 1. However, it is not limited thereto, and it may also be each block.

[0081] The PCU 30 performs bidirectional power conversion between the lithium ion secondary battery 1 and the motor generators 41 and 42 according to a control signal from the ECU 100. The PCU 30 is configured to be able to control the states of the motor generators 41 and 42 respectively. For example, the motor generator 41 can be set to the regenerative state (power generation state), and the motor generator 42 can be set to the power running state. The PCU 30 is provided corresponding to the motor generators 41 and 42, for example. It includes two inverters and a converter (both not shown) that boosts the DC voltage supplied to each inverter to a voltage higher than the output voltage of the lithium ion secondary battery 1.

[0082] <ecu100> In this embodiment, the ECU 100 of the control device 18 serves as the part that controls the charging and discharging of this embodiment.

[0083] The ECU 100 includes a CPU (Central Processing Unit) 101, a memory 102, and an input / output port (not shown) for inputting and outputting various signals. <Memory 102> The memory 102 includes a ROM (Read Only Memory) and a RAM (Random Access Memory). In addition, a storage medium such as an EPROM (erasable programmable read only memory), an SSD (Solid State Drive), an HDD (Hard Disc Drive), etc., which stores programs, maps, etc., is provided.

[0084] The ECU 100 controls the engine 50 and the PCU 30 based on the signals received from the respective measuring devices and the programs and maps stored in the memory 102, thereby controlling the charging and discharging of the lithium-ion secondary battery 1.

[0085] Figure 6 is a block diagram showing a part of the program stored in the memory 102. As Figure 6 shown, a program that causes the CPU 101 to function as a current measurement unit 102a is stored in the memory 102. Similarly, a voltage estimation unit 102b, an SOC estimation unit 102c, a voltage measurement unit 102d, a sample storage unit 102e, an SOC estimation error storage unit 102f, an upper and lower limit SOC calculation unit 102g, a used SOC calculation unit 102h, and a battery model correction unit 102i are stored. Programs for performing various processes and their results, etc., can be stored in the memory 102.

[0086] <Control method for charging and discharging of the lithium-ion secondary battery 1 of this embodiment> Figure 7 is a flowchart showing the process of the control method for charging and discharging of the lithium-ion secondary battery 1 of this embodiment. The following describes the control method for charging and discharging of the lithium-ion secondary battery 1 of this embodiment according to the Figure 7 flowchart.

[0087] First, start the one mounted on Figure 5 Control of the lithium-ion secondary battery 1 of the vehicle shown. Representatively, it is the case of exchanging the lithium-ion secondary battery 1 with an unknown usage history. Additionally, or it can also be the case of first applying the charge and discharge control method of the lithium-ion secondary battery 1 of the present embodiment to the lithium-ion secondary battery 1 already mounted.

[0088] <Obtain current / voltage / temperature information (S1)> First, obtain current / voltage / temperature information (S1). Here, Figure 5 The ECU 100 of the monitoring unit 40 shown obtains the current / voltage / temperature information of each single cell through the programs of the current measurement unit 102a, voltage measurement unit 102d, and SOC estimation unit 102c (for measuring temperature) of the memory 102.

[0089] Measure current A M [A] is measured by the current measurement device 40b, measure voltage V M [V] is measured by the voltage measurement device 40a, measure temperature T M [℃] is measured by the temperature measurement device 40c and stored in the memory 102. This process corresponds to the information acquisition step of the present embodiment.

[0090] <Input the current / temperature information into the battery model to estimate the battery state and estimate the battery voltage (S2)> Next, input the current / temperature information into the battery model to estimate the battery state and estimate the battery voltage (S2). Here, the ECU 100 passes the measured current A through the voltage estimation unit 102b M [A], measured temperature T M [℃] is input into Figure 2 the battery model shown to estimate the battery state and estimate the estimated voltage V E [V]. This process corresponds to the battery voltage estimation step of the present embodiment.

[0091] <Compare the measured voltage information with the estimated voltage to correct the battery state estimation (S3)> Next, compare the measured voltage information with the estimated voltage to correct the battery state estimation (S3). Here, the ECU 100 calculates the measured voltage V through the battery model correction unit 102i M [V] and the estimated voltage V E [V] difference ΔV [V]. In this case, when it is determined that the difference ΔV [V] is greater than a certain threshold, correct the battery model as needed. This process corresponds to the battery model correction step of the present embodiment.

[0092] <Is the current flowing within a certain range? (S4)> Next, it is determined whether the current is flowing within a certain range (S4). Here, it is determined by the program stored in the sample storage unit 102e of the ECU 100 whether a sample can be collected after a certain duration or at a current above a certain level (e.g., the above-mentioned "certain conditions"). This process is equivalent to a part of the sample collection step of the present embodiment. When it is determined that the current is not flowing within a certain range (S4: No), the process returns to S1.

[0093] <Collect a sample for calculating the latest SOC estimation error (S5)> When it is determined that the current is flowing within a certain range (S4: Yes), the ECU 100 stores the sample SP through the program stored in the sample storage unit 102e. When the current is below the predetermined current value [A] or the duration is a predetermined duration (e.g., less than 1 [second]), it is not collected as a sample. Then, data that meets the collection conditions is explored. This process is equivalent to a part of the sample collection step of the present embodiment.

[0094] <Classify the collected samples based on the normal SOC center to determine whether they are for upper limit side determination or lower limit side determination (S6)> Based on the normal SOC center, the collected samples are classified to determine whether they are for upper limit side determination or lower limit side determination (S6). In the present embodiment, if the sample is 50 [%] or less of the SOC, it is determined as a sample for lower limit side determination, and if the sample is greater than 50 [%] of the SOC, it is determined as a sample for upper limit side determination. Here, the ECU 100 also classifies and stores the samples through the program stored in the sample storage unit 102e. This process is equivalent to the sample classification step of the present embodiment.

[0095] <Have enough samples been collected? (S7)> After that, it is determined whether enough samples have been collected (S7). Regarding "enough" here, for example, in the present embodiment, it means collecting 10 effective samples for upper limit side determination SP H and 10 effective samples for lower limit side determination SP L until 10 samples are reached for each. It is considered that if 10 samples are collected, the influence of noise or unevenness on the charge and discharge control can be sufficiently reduced.

[0096] It should be noted that for the sample SP for upper limit side determination H and the sample SP for lower limit side determination L Before one of the two samples reaches the predetermined number, the other sample can be updated by adding or deleting new samples. If the number of samples of either sample has not reached the predetermined number (S7: No), the process returns to S1 and continues.

[0097] <Calculate the SOC estimation error on the upper limit side and the lower limit side of any number of samples collected (S8)> When a certain number of samples are collected (S7: Yes), the SOC estimation error on the upper limit side and the lower limit side is calculated (S8). It should be noted that the SOC estimation error can be calculated when both samples are collected. Here, the ECU 100 calculates the SOC estimation error through the program stored in the SOC estimation error storage unit 102f and stores the result. This process is equivalent to the SOC estimation error calculation step of this embodiment.

[0098] <Implementing upper and lower limit error protection processing (S9)> Here, the upper and lower limit error protection processing is implemented (S9). Here, the ECU 100 performs the processing using the program stored in the upper and lower limit SOC calculation unit 102g. This processing is performed only when necessary. That is, for example, Figure 1 The corrected usable SOC range S is shown UR If [%] is less than 20[%], the process is executed.

[0099] The upper limit side and the lower limit side SOC estimation error are calculated (S8). The upper limit error E based on the upper limit side and the lower limit side SOC estimation error H [%] and lower limit error E L [%], based on the SOC range S that can be used in the initial setting U0 [%] Limit upper limit error E H [%] and lower limit error E L The corrected usable SOC range S is determined accordingly. UR [%]. In this case, the upper limit error E H [%] and lower limit error E L [%] is limited to a certain range. This process is equivalent to the upper and lower limit protection processing step of this embodiment.

[0100] <Setting upper and lower limits of SOC according to upper / lower limit error (S10)> Set the upper and lower limits of SOC (S10) according to the upper / lower limit error, and set the corrected usable SOC range S UR [%] Once the setting is completed, the ECU 100 uses a program stored in the usable SOC calculation unit 102h to calculate the usable SOC range S after the correction. UR [%] Perform charge and discharge control of the lithium-ion secondary battery 1. This process is equivalent to the upper and lower limit SOC re-setting step of this embodiment.

[0101] <Is there a requirement to end charge and discharge? (S11)> For example, if there is a requirement to end charge and discharge such as stopping the use of the vehicle (S11: Yes), then end the charge and discharge and end the control method of the charge and discharge of the lithium-ion secondary battery 1 of this embodiment. If there is no such requirement to end discharge (S11: No), then return to S1 and continue the process.

[0102] (Function of this embodiment) Figure 7 The purpose of the charge and discharge control method of the lithium-ion secondary battery 1 of this embodiment shown is to quickly correct the SOC usage range according to the SOC estimation error by a simple method and control the charge and discharge safely and effectively.

[0103] Therefore, the control device first obtains the measured current A of the lithium-ion secondary battery 1 as the basis for control M [A], measured voltage V M [V], measured temperature T M [°C] (S1), and estimates the estimated voltage V E [V] (S2). Then, a sample for calculating the SOC estimation error E is used (S5). Here, this sample is the difference ΔV [V] between the measured voltage V M [V] and the estimated voltage V E [V]. Based on this measured voltage V M [V] and the estimated voltage V E [V], the upper limit error E H [%] and the lower limit error E L [%] are calculated (S8). By focusing on the voltage in this way, the upper limit error E H [%] and the lower limit error E L [%] can be calculated accurately and quickly.

[0104] And, if necessary, perform protection processing to limit the upper limit error E H [%] and the lower limit error E L [%]. Through this protection processing, a certain SOC [%] is ensured to control the charge and discharge.

[0105] Based on the upper limit error E H [%], re-set the upper limit L of the SOC used H , and based on the lower limit error E L , re-set the lower limit L of the SOC used L Redetermination is performed (S10). Thereafter, charging and discharging of the lithium ion secondary battery 1 are controlled based on the corrected available SOC range. With the configuration of the charging and discharging control method of the lithium ion secondary battery 1 of the present embodiment, the lithium ion secondary battery 1 can be effectively protected from overcharging and over-discharging. In addition, since the SOC [%] can be accurately estimated, the state of the lithium ion secondary battery 1 can be accurately grasped and its performance can be safely exhibited.

[0106] (Effect of the present embodiment) (1) According to the charging and discharging control method of the lithium ion secondary battery 1 of the present embodiment, there is an effect that the SOC usage range can be quickly corrected according to the SOC estimation error by a simple method, and charging and discharging can be controlled safely and effectively.

[0107] (2) In the present embodiment, in the SOC estimation error calculation step, the upper limit error E H [%] based on the upper limit side determination sample SP H aggregated by a certain number or more, and the lower limit error E L based on the lower limit side determination sample SP L [%] are calculated. Therefore, there is an effect that the upper limit error E H [%] and the lower limit error E L [%] of the accurate SOC can be calculated in real time.

[0108] (3) In the present embodiment, in the upper and lower limit SOC redetermination step, the upper limit L H of the used SOC is redetermined according to the upper limit error E H [%], and the lower limit L L of the used SOC is redetermined according to the lower limit error E L [%]. By making the above division, there is an effect that the range of SOC that can be used for charge and discharge control can be made a more appropriate range.

[0109] (4) In the upper and lower limit protection processing step of the present embodiment, when redetermination is performed based on the SOC estimation error E [%], a protection process is performed to optimize the available SOC range S U to, for example, 20 [%]. Therefore, even when the calculated SOC estimation error E [%] is large, the charge and discharge range performed by the control device can be appropriately protected, and there is an effect that it does not interfere with the operation of the vehicle.

[0110] (5) In the battery voltage estimation step, the estimated voltage is estimated as the closed-circuit voltage of the secondary battery, that is, the voltage V E [V]. Therefore, it has the effect of being able to calculate the estimated voltage V in real time. E [V].

[0111] (6) In this embodiment, the measured voltage V M [V] and the estimated voltage V E [V] are appropriately compared through the battery model correction step to correct the battery model. Therefore, it has the effect of correcting the battery model by feeding back the detected error and being able to improve the accuracy of the detection error of the SOC.

[0112] (7) The estimation error E of the SOC can be calculated in real time by using Equation 1. Therefore, it has the effect of being able to obtain the estimation error of the lithium-ion secondary battery 1 in real time.

[0113] (8) In the control method of the lithium-ion secondary battery 1 of this embodiment, even when a lithium-ion secondary battery 1 with a usage history is mounted in a vehicle, charging and discharging can be controlled safely and effectively according to the deterioration state of the battery.

[0114] (9) The control method of the lithium-ion secondary battery 1 of this embodiment can also be easily applied to existing vehicles. (Other examples) · In this embodiment, the plate-shaped lithium-ion secondary battery 1 mounted on a vehicle is illustrated, but it can also be mounted on a ship, an aircraft, or can also be applied to stationary batteries in homes and factories. In addition, its shape is not limited to a cylindrical shape or the like.

[0115] · In this embodiment, the lithium-ion secondary battery 1 is illustrated as the secondary battery, and it can also be other non-aqueous electrolyte secondary batteries, alkaline secondary batteries such as NiMH, all-solid-state batteries, etc., and its type is not limited.

[0116] · Figure 2 The battery model shown illustrates a simplified model, but it can also be a more complex model. · In this embodiment, the lithium-ion secondary battery 1 as a single cell constituting the battery module 1M as a battery pack is illustrated, but it can also be controlled using a single cell alone or can be in the form of a battery pack having a plurality of battery modules. In this case, the measured current A M [A], the measured voltage V M [V] can be directly measured for each single cell or can be measured using the battery pack.

[0117] · In this embodiment, the SOC error estimation is calculated using Equation 1, but in the present invention, the method of SOC error estimation is not limited to this. ·In this embodiment, the upper and lower limits of the division define the range of the SOC, but it can also be implemented in a manner that commonly processes the upper and lower limits.

[0118] ·In this embodiment, the initial available SOC range S U0 is 20 to 80 [%], but it can also be implemented below 20 [%] or above 80 [%] according to the characteristics of the battery.

[0119] ·The SOC range that can be used for control is made 20 [%] through the protection process, but it is not limited to this. ·The numerical values, numerical ranges, etc. of this embodiment are given as an example, but are not limited thereto. Those skilled in the art can appropriately optimize and implement according to the characteristics of the battery. The number of samples shown, the time of sample acquisition, etc. are examples and are appropriately optimized by those skilled in the art.

[0120] · Figure 7 The flowchart shown is an implementation example for illustration, but is not limited thereto. Those skilled in the art can add, delete, replace, and change the process for implementation. ·As long as it does not deviate from the scope of the claims, of course, those skilled in the art can add, delete, or change the composition of the present invention for implementation.

Claims

1. A method for controlling the charge and discharge of a secondary battery, which is a method for controlling the charge and discharge of a secondary battery using a control device, characterized in that: The method comprises the following steps: The information acquisition step is to acquire a measured current A obtained by measuring the secondary battery. M , measure voltage V M , measuring temperature T M information; The battery voltage estimation step is based on the measured current A obtained in the information acquisition step. M , measuring temperature T M The estimated voltage V E ; The sample collection step is to measure the voltage V used to calculate the estimated error E of the SOC when the current I flows through the secondary battery under certain conditions. M With the estimated voltage V E The difference ΔV of multiple samples; A sample classification step of classifying the plurality of samples collected in the sample collection step based on a reference value S based on a preset common SOC center, and classifying the samples as upper limit side determination samples SP H , or the lower limit judgment sample SP L ; The SOC estimation error calculation step is based on the collection of a certain number or more of the upper limit judgment samples SP H , calculate the available SOC range S U The upper limit L H The estimated error E is the upper limit error E H , based on the accumulation of a certain number of lower limit judgment samples SP L , calculate the usable SOC range S U The lower limit L L The estimated error E is the lower limit error E L ; as well as The upper and lower limit SOC resetting step is to control the usable SOC range S of the secondary battery. U , according to the upper limit error E H Then set the usable SOC range S U The upper limit L H , according to the lower limit error E L Then set the usable SOC range S U The lower limit L L .

2. The method for controlling the charge and discharge of a secondary battery according to claim 1, characterized in that: It further includes an upper and lower limit protection processing step, based on the reset usable SOC range S U The upper limit L H and the lower limit L L , implement the usable SOC range S U Perform optimized protection processing.

3. The method for controlling the charge and discharge of a secondary battery according to claim 2, characterized in that: In the upper and lower limit protection processing step, according to the upper limit L H and the lower limit L L The usable SOC range S U For a method of 20% or more, the upper limit L H and the lower limit L L Control by resetting.

4. The method for controlling the charge and discharge of a secondary battery according to claim 3, characterized in that: In the upper and lower limit protection processing step, according to the upper limit error E H Reset upper limit L H Set the upper limit error E H The range of the maximum difference ΔMax and the minimum difference ΔMin is based on the lower limit error E L Reset lower limit L L Set the lower limit error E L The range of the maximum difference ΔMax and the minimum difference ΔMin.

5. The method for controlling the charge and discharge of a secondary battery according to claim 1, characterized in that: In the battery voltage estimation step, the estimated voltage is estimated as the closed circuit voltage of the secondary battery, that is, the voltage V E .

6. The method for controlling the charge and discharge of a secondary battery according to claim 5, characterized in that: It further includes a battery model calibration step, wherein the measured voltage V M With the estimated voltage V E The comparison is performed to calibrate the battery model.

7. The method for controlling the charge and discharge of a secondary battery according to claim 6, characterized in that: At the measured voltage V M With the estimated voltage V E When the difference ΔV is greater than the threshold value Th, the battery model correction step is performed.

8. The method for controlling the charge and discharge of a secondary battery according to claim 1, characterized in that: In the sample classification step, the reference value S based on a preset normal SOC center for classifying the collected plurality of samples into upper limit determination samples or lower limit determination samples is set to a value greater than SOC40 and less than SOC60.

9. The method for controlling the charge and discharge of a secondary battery according to claim 1, characterized in that: In the SOC estimation error calculation step, the SOC estimation error is set to E, the number of sample collection is set to N, the number of sample collection times is set to k, and the measured voltage is set to V M , set the estimated voltage to V E , when the voltage corresponding to 1% of the SOC of the secondary battery is set to V1, The estimated error E is [Number 1] Calculated.

10. The method for controlling the charge and discharge of a secondary battery according to claim 1, characterized in that: The secondary battery is a power source for driving the vehicle. The control device is mounted on a vehicle.

11. The method for controlling charge and discharge of a secondary battery according to any one of claims 1 to 10, characterized in that: The secondary battery is a lithium ion secondary battery.

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