Economic evaluation method and device for energy storage of zinc-iron flow battery and storage medium

Abstract

The invention provides an economic evaluation method and device for energy storage of a zinc-iron flow battery and a storage medium. The economic evaluation method comprises the following specific steps: establishing an initial aging attenuation model of energy storage capacity attenuation of the zinc-iron flow battery according to an energy storage operation process of the zinc-iron flow battery; according to the influence of multiple factors on capacity aging attenuation, updating the initial aging attenuation model to obtain a zinc-iron flow battery energy storage capacity aging attenuation model under the influence of the multiple factors; and calculating the cost per kilowatt hour of the zinc-iron flow energy storage power station according to the aging attenuation model of the energy storage capacity of the zinc-iron flow battery on the basis of the energy storage leveling cost per kilowatt hour, thereby measuring the energy storage economy of the zinc-iron flow battery, and realizing a technical scheme capable of more accurately estimating the cost per kilowatt hour of the zinc-iron flow energy storage power station.

Description

Technical Field

[0001] The present invention relates to the technical field of battery energy storage, and in particular to an economic evaluation method, device and storage medium for zinc-iron liquid flow battery energy storage. Background Art

[0002] In the process of zinc-iron liquid flow battery energy storage system planning, the cost conversion of energy storage will be affected by the energy storage life of zinc-iron liquid flow battery, and in the actual process, the energy storage life of zinc-iron liquid flow battery will be affected by factors such as current rate, temperature and SOC (Storage Of Charge). During the operation of zinc-iron liquid flow battery energy storage, excessive current rate, excessive or low operating temperature, and excessive or low SOC range will accelerate the reduction of battery cycle capacity. Therefore, the attenuation of cycle capacity in the actual operation of zinc-iron liquid flow battery energy storage will cause the levelized cost of energy storage of the economic benefits of zinc-iron liquid flow battery energy storage planning calculated by traditional fixed parameters to be lower than the actual levelized cost of electricity, which is not conducive to accurately estimating the economic benefits of zinc-iron liquid flow battery energy storage.

[0003] Therefore, a technical solution is needed that can more accurately estimate the cost per kilowatt-hour of a zinc-iron liquid flow energy storage power station. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides an economic evaluation method, device and storage medium for zinc-iron liquid flow battery energy storage.

[0005] The present invention provides an economic evaluation method for zinc-iron liquid flow battery energy storage, comprising the following specific steps:

[0006] According to the operation process of zinc-iron liquid flow battery energy storage, an initial aging attenuation model of zinc-iron liquid flow battery energy storage capacity attenuation is established;

[0007] According to the influence of multiple factors on capacity aging attenuation, the initial aging attenuation model is updated to obtain an aging attenuation model of energy storage capacity of zinc-iron liquid flow battery under the influence of multiple factors;

[0008] Based on the levelized cost of energy storage per kilowatt-hour, the cost of energy storage per kilowatt-hour of the zinc-iron liquid flow battery power station is calculated according to the zinc-iron liquid flow battery energy storage capacity aging attenuation model, so as to measure the economic efficiency of zinc-iron liquid flow battery energy storage.

[0009] In a possible implementation, the aging attenuation model of the zinc-iron liquid flow battery energy storage capacity is:

[0010] C=C0·(1-k Loss ) cyc -α day,cyc cyc,

[0011] In the formula, C0 is the initial capacity life of zinc-iron liquid flow battery energy storage, C is the current capacity life of zinc-iron liquid flow battery energy storage, k Loss is the predicted loss coefficient of zinc-iron flow battery energy storage, α day,cyc It is a parameter that converts the calendar aging effect of zinc-iron liquid flow battery energy storage into the number of cycle aging under the influence of calendar aging, and cyc is the current number of cycles of zinc-iron liquid flow battery energy storage.

[0012] In a possible implementation, the predicted loss coefficient is modeled as the product of multiple influencing factors, and its expression is:

[0013] k Loss =k TI ·k SOC ·k cyc ·k SOH ,

[0014] In the formula, k TI is the function of the energy storage life decay temperature and current rate influencing factor of the zinc-iron liquid flow battery, k SOC is the charge state influencing factor function of the energy storage life decay of zinc-iron liquid flow battery, k cyc is the average current influencing factor of the energy storage life decay of zinc-iron flow battery, k SOH It is a nonlinear accelerating factor affecting the energy storage life attenuation of zinc-iron liquid flow batteries.

[0015] In a possible implementation, the expression of the energy storage life attenuation temperature and current rate influencing factor function of the zinc-iron liquid flow battery is:

[0016] k TI =a1+a2·T+a3·I+a4·T 2 +a5·T·I+a6·I 2 ,

[0017] Where T is temperature, I is current rate, and parameter values ​​a1 to a6 are parameter results based on the least squares fitting of the capacity loss during the aging process of zinc-iron liquid flow battery energy storage at different temperatures and discharge rates.

[0018] In a possible implementation, when the zinc-iron liquid flow battery energy storage life decay state of charge influence factor function is expressed in the form of a normalized double exponential function, its expression is:

[0019]

[0020] Where SOC is the state of charge range of the zinc-iron liquid flow battery energy storage operation, and the parameter value is from a7e to a 11 It is the normalized parameter of the double exponential function fitting of the aging loss gap in different state of charge ranges.SOC The integral is 1.

[0021] In a possible implementation, the average current influencing factor of the energy storage life decay of the zinc-iron liquid flow battery is constructed by the ratio of the integrated electric quantity of the segmented current to the integrated electric quantity of the total current, and its expression is:

[0022]

[0023] Where n is the number of segment currents, i is the segment current sequence number, I segment,i is the current intensity of the i-th segment, t i is the segment current operation time of the i-th segment, t en d is the total operation time of zinc-iron liquid flow battery energy storage, I avg is the average current intensity.

[0024] In a possible implementation, the expression of the nonlinear acceleration influencing factor of the zinc-iron liquid flow battery energy storage life decay is:

[0025]

[0026] In a possible implementation, the expression for calculating the electricity cost of the zinc-iron liquid flow energy storage power station is:

[0027] C con =Cap·C int ,

[0028] C ope =Cap·C year ,

[0029] Loss year =(1-EOL) / Y,

[0030]

[0031] EOL=C0·(1-k Loss ) Cyc -α day,cyc Cyc,

[0032]

[0033] In the formula, C con is the total initial investment and construction cost of zinc-iron flow battery energy storage, Cap is the planned construction capacity of zinc-iron flow battery, C int is the initial zinc-iron flow battery energy storage investment and construction unit price, C ope is the total annual operation and maintenance cost of zinc-iron liquid flow battery energy storage, C year is the annual operation and maintenance cost of zinc-iron liquid flow battery energy storage, Loss yearis the average annual loss of the zinc-iron liquid flow energy storage power station, EOL is the end capacity of the zinc-iron liquid flow energy storage power station, Y is the estimated service life of the zinc-iron liquid flow energy storage power station, Energy i is the annual power of the zinc-iron liquid flow energy storage power station, Cyc is the cycle life of the zinc-iron liquid flow battery, DOD is the cycle depth of the zinc-iron liquid flow energy storage power station, η is the charge and discharge efficiency of the zinc-iron liquid flow energy storage power station, i y is the number of operating years, Ded tax,present is the discounted present value of total tax exemptions for zinc-iron liquid flow energy storage power station, tax is the tax rate, Ded is the annual discount rate, C ope,present is the discounted present value of the total operation and maintenance cost of the zinc-iron liquid flow energy storage power station, Energy present It is the discounted present value of the total electricity of the zinc-iron liquid flow energy storage power station, and LCOS is the cost per kilowatt-hour of the zinc-iron liquid flow energy storage power station.

[0034] The present invention also provides an economic evaluation device for zinc-iron liquid flow battery energy storage, comprising:

[0035] The initial module is used to establish an initial aging attenuation model of the zinc-iron liquid flow battery energy storage capacity attenuation according to the zinc-iron liquid flow battery energy storage operation process;

[0036] A model generation module is used to update the initial aging attenuation model according to the influence of multiple factors on capacity aging attenuation, so as to obtain an aging attenuation model of the energy storage capacity of the zinc-iron liquid flow battery under the influence of multiple factors;

[0037] The evaluation module is used to calculate the cost per kilowatt-hour of the zinc-iron liquid flow energy storage power station based on the levelized cost per kilowatt-hour of energy storage and the aging attenuation model of the zinc-iron liquid flow battery energy storage capacity, so as to measure the economic efficiency of the zinc-iron liquid flow battery energy storage.

[0038] The present invention also provides a computer-readable storage medium, wherein the computer-readable storage medium includes a stored program, and the program executes the above-mentioned economic evaluation method when it is run.

[0039] The technical solution provided by the present invention has at least the following beneficial effects:

[0040] By analyzing the causes of the aging process of zinc-iron liquid flow battery energy storage operation, a zinc-iron liquid flow battery energy storage capacity aging attenuation model under the influence of multiple factors was proposed, and based on the levelized cost of energy storage, the cost of zinc-iron liquid flow energy storage power station was calculated. This can more significantly distinguish the economic cost of zinc-iron liquid flow battery energy storage under different operating conditions, so that energy storage builders can more accurately estimate the actual operation planning and construction costs of zinc-iron liquid flow battery energy storage, and guide energy storage construction to make more accurate judgments. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1A flow chart of an economic evaluation method for zinc-iron liquid flow battery energy storage provided by an embodiment of the present invention;

[0042] Figure 2 A function diagram of the SOC influencing factor of the energy storage life decay of a zinc-iron liquid flow battery provided in an embodiment of the present invention;

[0043] Figure 3 A comparison chart of predicted and actual aging capacity of a zinc-iron liquid flow battery energy storage provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0044] In order to deepen the understanding of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The embodiments are only used to explain the present invention and do not limit the protection scope of the present invention.

[0045] Please refer to Figures 1 to 3 The present invention provides an economic evaluation method for zinc-iron liquid flow battery energy storage, comprising the following specific steps:

[0046] S100: According to the zinc-iron liquid flow battery energy storage operation process, an initial aging attenuation model of the zinc-iron liquid flow battery energy storage capacity attenuation is established;

[0047] S200: updating the initial aging attenuation model according to the influence of multiple factors on the capacity aging attenuation, and obtaining an aging attenuation model of the zinc-iron liquid flow battery energy storage capacity under the influence of multiple factors;

[0048] S300: Taking the levelized cost of energy storage as a benchmark, the cost of energy storage of the zinc-iron liquid flow battery power station is calculated according to the zinc-iron liquid flow battery energy storage capacity aging attenuation model, so as to measure the economic efficiency of zinc-iron liquid flow battery energy storage.

[0049] In this embodiment, the economic evaluation of zinc-iron liquid flow battery energy storage is combined with the aging and attenuation process of its operating conditions, so that the cost of zinc-iron liquid flow battery energy storage can be more accurately calculated according to the actual situation, which is more conducive to the construction planning of zinc-iron liquid flow battery. The economic evaluation method of zinc-iron liquid flow battery energy storage is carried out under the scenario of considering multiple factors affecting battery life aging. The initial aging and attenuation model can be expressed as:

[0050] C=C0-α day,eye .cyc,

[0051] In the formula, C0 is the initial capacity life of zinc-iron liquid flow battery energy storage, C is the current capacity life of zinc-iron liquid flow battery energy storage, α day,cyc It is a parameter that converts the calendar aging effect of zinc-iron liquid flow battery energy storage into the number of cycle aging under the influence of calendar aging, and cyc is the current number of cycles of zinc-iron liquid flow battery energy storage.

[0052] On the basis of the initial aging attenuation model, the influence of multiple factors on capacity aging attenuation can be considered, and the initial aging attenuation model can be updated to obtain the zinc-iron liquid flow battery energy storage capacity aging attenuation model.

[0053] When calculating the cost per kilowatt-hour of a zinc-iron liquid flow energy storage power station, the levelized cost per kilowatt-hour of energy storage can be used as a benchmark, combined with the zinc-iron liquid flow battery energy storage capacity aging attenuation model and the zinc-iron liquid flow battery energy storage cost per kilowatt-hour accounting model for corresponding calculations.

[0054] In a possible implementation, the following zinc-iron liquid flow battery energy storage capacity aging attenuation model can be established based on the relationship that the available capacity of the zinc-iron liquid flow battery energy storage attenuates with the increase of the number of cycles and the service time:

[0055] C=C0·(1-k Loss ) cyc -α day,cyc cyc,

[0056] In the formula, C0 is the initial capacity life of zinc-iron liquid flow battery energy storage, C is the current capacity life of zinc-iron liquid flow battery energy storage, k Loss is the predicted loss coefficient of zinc-iron flow battery energy storage, α day,cyc It is a parameter that converts the calendar aging effect of zinc-iron liquid flow battery energy storage into the number of cycle aging under the influence of calendar aging. Cyc is the current number of cycles of zinc-iron liquid flow battery energy storage.

[0057] In this embodiment, the predicted loss coefficient k Loss It is determined by multiple factors such as current rate, temperature, and charge state range. Zinc-iron liquid flow battery energy storage is based on the redox reaction of zinc and iron ions in an aqueous alkaline electrolyte environment to achieve normal charging and discharging of the energy storage battery. Zinc-iron liquid flow battery energy storage will experience zinc dendrite plasma precipitation as the number of charge and discharge times increases and the service life increases, which is manifested externally as a decrease in the cycle capacity of the zinc-iron liquid flow battery energy storage and an increase in the internal resistance of the battery. For zinc-iron liquid flow battery energy storage, for the same battery at the same aging level, the impact of increased internal resistance on battery operation is too small compared to the impact of reduced cycle capacity. Therefore, the decay rate of the zinc-iron liquid flow battery energy storage cycle capacity is usually used to quantify the impact of zinc-iron liquid flow battery energy storage aging decay. Therefore, the zinc-iron liquid flow battery energy storage aging prediction model constructed by the present invention, that is, the zinc-iron liquid flow battery energy storage capacity aging decay model, simultaneously considers the impact of the number of cycles and the battery service life, that is, calendar aging, on the battery capacity decay.

[0058] In one possible implementation, the predicted loss coefficient of zinc-iron flow battery energy storage can be modeled as the product of multiple influencing factors, and its expression is:

[0059] k Loss =kTI ·k SOC ·k cyc ·k SOH ,

[0060] In the formula, k TI is the function of the energy storage life decay temperature and current rate influencing factor of the zinc-iron liquid flow battery, k SOC is the charge state influencing factor function of the energy storage life decay of zinc-iron liquid flow battery, k cyc is the average current influencing factor of the energy storage life decay of zinc-iron flow battery, k SOH It is a nonlinear accelerating factor affecting the energy storage life attenuation of zinc-iron liquid flow batteries.

[0061] In this embodiment, since the aging process of zinc-iron liquid flow battery energy storage is affected by many factors, the present invention predicts the loss coefficient k of zinc-iron liquid flow battery energy storage. Loss Multi-factor analysis modeling is performed. When the predicted loss coefficient is expressed in functional form, it can be composed of different basic influencing factor functions, including the energy storage life attenuation temperature of the zinc-iron liquid flow battery and the current rate influencing factor function k TI , the charge state influencing factor function k of zinc-iron liquid flow battery energy storage life decay SOC , Factors affecting the average current of zinc-iron flow battery energy storage life attenuation k cyc , Nonlinear acceleration influencing factors of zinc-iron liquid flow battery energy storage life attenuation k SOH .

[0062] In a possible implementation, due to the nonlinear characteristics of temperature and current rate on the aging attenuation of zinc-iron liquid flow battery energy storage, a function of the temperature and current rate influencing factor of zinc-iron liquid flow battery energy storage life attenuation in the form of a binary quadratic polynomial function can be established based on measured data. The expression is:

[0063] k TI =a1+a2·T+a3·I+a4·T 2 +a5·T·I+a6·I 2 ,

[0064] Where T is temperature, I is current rate, and parameter values ​​a1 to a6 are parameter results based on the least squares fitting of the capacity loss during the aging process of zinc-iron liquid flow battery energy storage at different temperatures and discharge rates.

[0065] In this embodiment, due to different influencing mechanisms and different degrees of influence on the aging of zinc-iron liquid flow battery energy storage, different basic influencing factor functions need to be modeled separately according to their influence on the aging characteristics of zinc-iron liquid flow battery energy storage. TI It can be established as a quadratic polynomial function of two variables.

[0066] In a possible implementation, since the SOC interval affects the energy storage life of the flow battery, too high or too low SOC will accelerate the aging of the flow battery. According to experimental data, the energy storage life of the zinc-iron flow battery decays most slowly in the range of 0.4-0.6. Therefore, the present invention establishes a normalized double exponential function for the zinc-iron flow battery energy storage life decay SOC influence factor function k SOC Due to its normalized characteristics, the integral in the entire 0-1 operating range is 1. The zinc-iron liquid flow battery energy storage can be integrated in different SOC intervals to obtain the corresponding life attenuation SOC influence factor function, and its basic image is as follows Figure 2 As shown. The expression of the SOC influencing factor function of the energy storage life decay of zinc-iron liquid flow battery is:

[0067]

[0068] Where SOC is the state of charge range of the zinc-iron liquid flow battery energy storage operation, and the parameter value is from a7e to a 11 It is the normalized parameter of the double exponential function fitting of the aging loss gap in different state of charge ranges. SOC The integral is 1.

[0069] In a possible implementation, excessive current intensity of zinc-iron flow battery energy storage at different times will also lead to segmented attenuation, so it is also necessary to consider the average current influencing factor of zinc-iron flow battery energy storage life attenuation. In this regard, the present invention proposes to establish the average current influencing factor of zinc-iron flow battery energy storage life attenuation based on the ratio of the integrated electric quantity of the segmented current to the integrated electric quantity of the total current, and its expression is:

[0070]

[0071] Where n is the number of segment currents, i is the segment current sequence number, I segment,i is the current intensity of the i-th segment, t i is the segment current operation time of the i-th segment, t end is the total operation time of zinc-iron flow battery energy storage, I avg is the average current intensity.

[0072] In a possible implementation, since the energy storage life decay of zinc-iron liquid flow battery has nonlinear accelerated decay, the present invention proposes a function of nonlinear accelerated influencing factors of energy storage life decay of zinc-iron liquid flow battery established based on this, which can be established as a quadratic proportional function, and its expression is:

[0073]

[0074] In one possible implementation, in terms of cost assessment of energy storage construction, the general energy storage cost evaluation index in China and internationally is the levelized cost of storage (LCOS) based on the modeling of the entire life cycle of energy storage, referred to as the cost per kilowatt-hour. Therefore, the present invention uses the cost per kilowatt-hour as a criterion for measuring the economic efficiency of zinc-iron liquid flow battery energy storage. On this basis, the present invention takes into account the impact of multiple factors under different operating conditions on the aging and attenuation of zinc-iron liquid flow battery energy storage. The aging and attenuation of the zinc-iron liquid flow battery energy storage will cause the annual available capacity in the calculation of the cost per kilowatt-hour to continue to decline.

[0075] In specific implementation, the cycle life Cyc of the zinc-iron liquid flow battery can be calculated according to the above zinc-iron liquid flow battery energy storage capacity aging attenuation model, so as to establish the zinc-iron liquid flow battery energy storage kilowatt-hour cost accounting model LCOS, and calculate the kilowatt-hour cost of the zinc-iron liquid flow energy storage power station through the zinc-iron liquid flow battery energy storage kilowatt-hour cost accounting model LCOS. Its evaluation index is the levelized kilowatt-hour cost based on the modeling of the entire life cycle of zinc-iron liquid flow battery energy storage, and its specific contents are as follows:

[0076] C con =Cap·C int ,

[0077] C ope =Cap·C year ,

[0078] Loss year =(1-EOL) / Y,

[0079]

[0080] In the formula, C con is the total initial investment and construction cost of zinc-iron flow battery energy storage, Cap is the planned construction capacity of zinc-iron flow battery, C int is the initial zinc-iron flow battery energy storage investment and construction unit price, C ope is the total annual operation and maintenance cost of zinc-iron liquid flow battery energy storage, C year is the annual operation and maintenance cost of zinc-iron liquid flow battery energy storage, Loss year is the average annual loss of the zinc-iron liquid flow energy storage power station, EOL is the end capacity of the zinc-iron liquid flow energy storage power station, Y is the estimated service life of the zinc-iron liquid flow energy storage power station, Energy i is the annual power of the zinc-iron liquid flow energy storage power station, Cyc is the cycle life of the zinc-iron liquid flow battery, DOD is the cycle depth of the zinc-iron liquid flow energy storage power station, η is the charge and discharge efficiency of the zinc-iron liquid flow energy storage power station, i y is the number of operating years, Ded tax,presentis the discounted present value of total tax exemptions for zinc-iron liquid flow energy storage power station, tax is the tax rate, Ded is the annual discount rate, C ope,present is the discounted present value of the total operation and maintenance cost of the zinc-iron liquid flow energy storage power station, Energy present It is the discounted present value of the total electricity of the zinc-iron liquid flow energy storage power station, and LCOS is the cost per kilowatt-hour of the zinc-iron liquid flow energy storage power station.

[0081] In specific implementation, since the cycle life Cyc of the zinc-iron flow battery will continue to decrease with its aging, the zinc-iron flow battery energy storage cost accounting model and the zinc-iron flow battery energy storage capacity aging attenuation model can be combined to calculate the EOL through the following formula:

[0082] EOL=C0·(1-k Loss ) Cyc -α day,cyc Cyc,

[0083] When the termination capacity of the zinc-iron liquid flow energy storage power station is given, the cycle life of the zinc-iron liquid flow energy storage power station, i.e. the zinc-iron liquid flow battery, is solved, so as to more accurately estimate the cost per kilowatt-hour of the zinc-iron liquid flow energy storage power station according to actual conditions.

[0084] In a specific embodiment, the present invention uses the proposed aging attenuation prediction model of the zinc-iron liquid flow energy storage power station, that is, the zinc-iron liquid flow battery energy storage capacity aging attenuation model, to compare with the actual zinc-iron liquid flow battery capacity attenuation measurement data, and selects the zinc-iron liquid flow energy storage power station test data with a temperature of 25°C and a discharge rate of 1C and 2C respectively. Among them, the measurement data is the data obtained when fully charged and discharged in the range of 0-1, so k SOC =1; at the same time, the measured data is obtained when the fixed current is uniformly charged and discharged, so k cyc = 1. The aging attenuation prediction model parameters of other zinc-iron liquid flow energy storage power stations are shown in Table 1:

[0085] Table 1 Parameters of the aging attenuation prediction model for zinc-iron liquid flow energy storage power station

[0086]

[0087]

[0088] The present invention uses the proposed aging attenuation prediction model of the zinc-iron liquid flow energy storage power station and the actual zinc-iron liquid flow battery capacity attenuation measurement data results as shown in the figure. Figure 3 .like Figure 3The aging attenuation prediction model of the zinc-iron liquid flow energy storage power station proposed in the present invention can accurately estimate the actual aging attenuation process, and the error with the actual aging data is small: the average prediction error is 1.4084% under 1C, 25℃ conditions, and the average prediction error is 0.8647% under 2C, 25℃ conditions.

[0089] For the calculation of the electricity cost per kilowatt-hour of the zinc-iron liquid flow energy storage station, the electricity cost per kilowatt-hour of the zinc-iron liquid flow energy storage station is also considered when the temperature is 25°C and the discharge rate is 1C and 2C respectively. The parameters of the electricity cost per kilowatt-hour of the zinc-iron liquid flow energy storage station are shown in Table 2:

[0090] Table 2 Calculation index of electricity cost of zinc-iron liquid flow energy storage power station

[0091]

[0092] The present invention combines the previous aging attenuation model to obtain the kilowatt-hour cost of zinc-iron liquid flow energy storage power station under different operating conditions, and compares it with the traditional kilowatt-hour cost calculation method with a fixed number of cycles and without considering aging attenuation. Among them, the traditional method is to fix the number of cycles of the zinc-iron liquid flow energy storage power station to 5000 times, and the kilowatt-hour cost data is as shown in Table 3:

[0093] Table 3. The electricity cost of zinc-iron liquid flow energy storage power station under different operating conditions

[0094]

[0095] The results show that the traditional method has a constant cost per kilowatt-hour of 0.5988 yuan / Wh due to the neglect of the change in current rate. The economic evaluation method of zinc-iron liquid flow battery energy storage under the influence of multiple factors on battery life aging proposed in the present invention can obtain different and more reasonable zinc-iron liquid flow battery energy storage costs per kilowatt-hour according to the changes in multiple working conditions compared to the traditional method. As shown in Table 3, as the current rate increases from 1C to 2C, the cost per kilowatt-hour of the zinc-iron liquid flow energy storage power station increases from 0.5480 / Wh to 0.6107 yuan / Wh, which is more in line with the actual situation and can fully reflect the higher life loss of the zinc-iron liquid flow energy storage power station caused by high current. It can be seen from this that the present invention has significant advantages over the existing methods and is of great significance.

[0096] The present invention uses the zinc-iron liquid flow energy storage power station at 25℃, 1C and 2C as the test object, and tests the accuracy of the life prediction model proposed by the present invention and the superiority of the cost-per-kilowatt-hour accounting method. The results show that the average error between the prediction model proposed by the present invention and the actual measurement data is low, which is 1.4084% and 0.8647% respectively. At the same time, the cost-per-kilowatt-hour accounting method of the zinc-iron liquid flow energy storage power station proposed by the present invention can obtain a cost-per-kilowatt-hour that is more in line with the actual working condition changes.

[0097] It can be seen that the method proposed in the present invention can obtain more accurate estimation of the cost per kilowatt-hour of the zinc-iron liquid flow energy storage power station under different working conditions, which is beneficial to the economic planning of the construction of the zinc-iron liquid flow energy storage power station.

[0098] The present invention also provides an economic evaluation device for zinc-iron liquid flow battery energy storage, comprising:

[0099] The initial module is used to establish an initial aging attenuation model of the zinc-iron liquid flow battery energy storage capacity attenuation according to the zinc-iron liquid flow battery energy storage operation process;

[0100] A model generation module is used to update the initial aging attenuation model according to the influence of multiple factors on capacity aging attenuation, so as to obtain an aging attenuation model of the energy storage capacity of the zinc-iron liquid flow battery under the influence of multiple factors;

[0101] The evaluation module is used to calculate the cost per kilowatt-hour of the zinc-iron liquid flow energy storage power station based on the levelized cost per kilowatt-hour of energy storage and the aging attenuation model of the zinc-iron liquid flow battery energy storage capacity, so as to measure the economic efficiency of the zinc-iron liquid flow battery energy storage.

[0102] The present invention also provides a computer-readable storage medium, wherein the computer-readable storage medium includes a stored program, and the program executes the above-mentioned economic evaluation method when it is run.

[0103] The above embodiments should not limit the present invention in any way, and any technical solutions obtained by equivalent replacement or equivalent conversion shall fall within the protection scope of the present invention.

Claims

1. An economic evaluation method for zinc-iron flow battery energy storage, characterized in that: The specific steps include: According to the operation process of zinc-iron liquid flow battery energy storage, an initial aging attenuation model of zinc-iron liquid flow battery energy storage capacity attenuation is established; According to the influence of multiple factors on capacity aging attenuation, the initial aging attenuation model is updated to obtain an aging attenuation model of energy storage capacity of zinc-iron liquid flow battery under the influence of multiple factors; Based on the levelized cost of energy storage per kilowatt-hour, the cost of energy storage per kilowatt-hour of the zinc-iron liquid flow battery power station is calculated according to the zinc-iron liquid flow battery energy storage capacity aging attenuation model, so as to measure the economic efficiency of zinc-iron liquid flow battery energy storage.

2. The economic evaluation method according to claim 1, characterized in that: The aging attenuation model of the zinc-iron liquid flow battery energy storage capacity is: C=C0·(1-k Loss ) cyc -α day,cyc ·cycle, In the formula, C0 is the initial capacity life of zinc-iron liquid flow battery energy storage, C is the current capacity life of zinc-iron liquid flow battery energy storage, k Loss is the predicted loss coefficient of zinc-iron flow battery energy storage, α day,cyc It is a parameter that converts the calendar aging effect of zinc-iron liquid flow battery energy storage into the number of cycle aging under the influence of calendar aging, and cyc is the current number of cycles of zinc-iron liquid flow battery energy storage.

3. The economic evaluation method according to claim 2, characterized in that: The predicted loss coefficient is modeled as the product of multiple influencing factors, and its expression is: k Loss =k TI ·k SOC ·k cyc ·k SOH , In the formula, k TI is the function of the energy storage life decay temperature and current rate influencing factor of the zinc-iron liquid flow battery, k SOC is the charge state influencing factor function of the energy storage life decay of zinc-iron liquid flow battery, k cyc is the average current influencing factor of the energy storage life decay of zinc-iron flow battery, k SOH It is a nonlinear accelerating factor affecting the energy storage life attenuation of zinc-iron liquid flow batteries.

4. The economic evaluation method according to claim 3, characterized in that: The expression of the energy storage life attenuation temperature and current rate influencing factor function of the zinc-iron liquid flow battery is: k TI =a1+a2·T+a3·I+a4·T 2 +a5·T·I+a6·I 2 , Where T is temperature, I is current rate, and parameter values ​​a1 to a6 are parameter results based on the least squares fitting of the capacity loss during the aging process of zinc-iron liquid flow battery energy storage at different temperatures and discharge rates.

5. The economic evaluation method according to claim 3, characterized in that: When the energy storage life decay state of charge factor function of the zinc-iron liquid flow battery is expressed in the form of a normalized double exponential function, its expression is: Where SOC is the state of charge range of the zinc-iron liquid flow battery energy storage operation, and the parameter value is from a7e to a 11 It is the normalized parameter of the double exponential function fitting of the aging loss gap in different state of charge ranges. SOC The integral is 1.

6. The economic evaluation method according to claim 3, characterized in that: The average current influencing factor of the energy storage life attenuation of the zinc-iron liquid flow battery is constructed by the ratio of the integrated electric quantity of the segmented current to the integrated electric quantity of the total current, and its expression is: Where n is the number of segment currents, i is the segment current sequence number, I segment,i is the current intensity of the i-th segment, t i is the segment current operation time of the i-th segment, t en d is the total operation time of zinc-iron liquid flow battery energy storage, I avg is the average current intensity.

7. The economic evaluation method according to claim 3, characterized in that: The expression of the nonlinear acceleration influencing factor of the zinc-iron liquid flow battery energy storage life attenuation is:

8. The economic evaluation method according to claim 2, characterized in that: The expression for calculating the electricity cost of the zinc-iron liquid flow energy storage power station is: C con =Cap·C int , C ope =Cap·C year , Loss year =(1-EOL) / Y, EOL=C0·(1-k Loss ) Cyc -a day,cyc ·Cyc, In the formula, C con is the total initial investment and construction cost of zinc-iron flow battery energy storage, Cap is the planned construction capacity of zinc-iron flow battery, C int is the initial zinc-iron flow battery energy storage investment and construction unit price, C ope is the total annual operation and maintenance cost of zinc-iron liquid flow battery energy storage, C year is the annual operation and maintenance cost of zinc-iron liquid flow battery energy storage, Loss year is the average annual loss of the zinc-iron liquid flow energy storage power station, EOL is the end capacity of the zinc-iron liquid flow energy storage power station, Y is the estimated service life of the zinc-iron liquid flow energy storage power station, Energy i is the annual power of the zinc-iron liquid flow energy storage power station, Cyc is the cycle life of the zinc-iron liquid flow battery, DOD is the cycle depth of the zinc-iron liquid flow energy storage power station, η is the charge and discharge efficiency of the zinc-iron liquid flow energy storage power station, i y is the number of operating years, Ded tax,present is the discounted present value of total tax exemptions for zinc-iron liquid flow energy storage power station, tax is the tax rate, Ded is the annual discount rate, C ope,present is the discounted present value of the total operation and maintenance cost of the zinc-iron liquid flow energy storage power station, Energy present It is the discounted present value of the total electricity of the zinc-iron liquid flow energy storage power station, and LCOS is the cost per kilowatt-hour of the zinc-iron liquid flow energy storage power station.

9. An economic evaluation device for zinc-iron liquid flow battery energy storage, characterized in that: include: The initial module is used to establish an initial aging attenuation model of the zinc-iron liquid flow battery energy storage capacity attenuation according to the zinc-iron liquid flow battery energy storage operation process; A model generation module is used to update the initial aging attenuation model according to the influence of multiple factors on capacity aging attenuation, so as to obtain an aging attenuation model of the energy storage capacity of the zinc-iron liquid flow battery under the influence of multiple factors; The evaluation module is used to calculate the cost per kilowatt-hour of the zinc-iron liquid flow energy storage power station based on the levelized cost per kilowatt-hour of energy storage and the aging attenuation model of the zinc-iron liquid flow battery energy storage capacity, so as to measure the economic efficiency of the zinc-iron liquid flow battery energy storage.

10. A computer-readable storage medium, the computer-readable storage medium comprising a stored program, characterized in that: When the program is run, the economic evaluation method according to any one of claims 1 to 8 is executed.

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