CN116315195A - A lithium-ion battery system intelligent discharge method, device and medium for energy storage - Google Patents

Abstract

The invention discloses an intelligent discharging method, equipment and medium of a lithium ion battery system for energy storage, which comprises the following specific steps: s1, acquiring a charge state of a battery system, discharge power and discharge time of the battery system, and determining whether the battery system is in a start-up discharge state or not; s2, acquiring a temperature state parameter and a discharge state parameter of the battery system in the discharge process, and judging whether cooling is required to be started in the discharge process of the battery system; s3, acquiring the heating value in the delta t period and the heat required by the self heat capacity of the battery system in the discharging process of the battery system, determining the time for starting cooling in the discharging process of the battery system, and determining the time for starting cooling in the discharging process of the battery system according to the heating value in the discharging process of the battery system and the heat required by the self heat capacity of the battery system, so as to ensure that the battery system is maintained in a certain temperature range, ensure the service life of the battery system and ensure the service life requirement of an energy storage power station.

Description

A lithium-ion battery system intelligent discharge method, device and medium for energy storage

technical field

The invention relates to the technical field of electrochemical energy storage, in particular to an intelligent discharge method, equipment and medium for a lithium-ion battery system for energy storage.

Background technique

At present, the commonly used technical solutions for cooling the battery system are:

Solution 1: The lithium-ion battery system for energy storage is not equipped with a liquid cooling device, and only an air duct is installed inside the battery system. Cooling during discharge.

Solution 2: Design a liquid cooling system for lithium-ion battery systems for energy storage. When the battery system is discharging, when the battery system temperature > T0 setting, turn on the liquid cooling system to cool down the battery system. When the maximum temperature Tmax of the battery system is less than a certain When the temperature is reached, exit the cooling.

In Scheme 1, the lithium-ion power battery for energy storage is not equipped with a liquid cooling system, and the battery system is cooled by forced air cooling or natural air cooling. It is effectively controlled, so that the life of the battery system decays faster.

Option 2, the lithium-ion battery system for energy storage is equipped with a cooling system. When the battery system is charging and discharging, when the temperature of the battery system exceeds a certain value, the cooling is turned on until the temperature of the battery system meets the requirements, but the cooling threshold is set As the battery system ages, the maximum temperature of the battery system cannot be effectively controlled during the discharge process of the battery system, which will lead to a decrease in the discharge power of the battery system and at the same time lead to a decrease in the life of the battery system. The decay is faster; if the set cooling threshold is low, it may cause waste of energy for cooling.

Contents of the invention

The technical problem to be solved by the present invention is that the battery system will generate heat and heat up during discharge, and the temperature rise will exceed the maximum temperature that the battery system can withstand, reducing the life of the battery system. The purpose is to provide an intelligent discharge method for lithium-ion battery systems for energy storage , equipment and media, according to the state of charge of the battery system, the discharge power and discharge time of the battery system, determine whether the battery system is in the discharge state, determine whether the cooling needs to be turned on during the discharge process of the battery system, and according to the calorific value during the discharge process of the battery system and the heat required by the battery system's own heat capacity to determine the cooling time that needs to be turned on during the discharge process of the battery system. In this way, the temperature of the battery system is maintained within a certain temperature range, ensuring the service life of the battery system, ensuring the life requirements of the energy storage power station and the unlimited short-term discharge power requirements.

The present invention realizes through following technical scheme:

The first aspect of the present invention provides an intelligent discharge method for a lithium-ion battery system for energy storage, including the following specific steps:

S1. Obtain the state of charge of the battery system, the discharge power and discharge time of the battery system, and determine whether the battery system is in the discharge state;

S2. Obtain the temperature state parameters and discharge state parameters of the battery system during the discharge process, and determine whether cooling needs to be turned on during the discharge process of the battery system;

S3. Obtain the calorific value of the battery system during the Δt period during the discharge process and the heat required by the battery system's own heat capacity, and determine the cooling time of the battery system during the discharge process.

According to the state of charge of the battery system, the discharge power and the discharge time of the battery system, the present invention determines whether the battery system is in the discharge state, and judges whether the cooling needs to be turned on during the discharge process of the battery system. The heat required by the system's own heat capacity determines the cooling time that needs to be turned on during the discharge process of the battery system. In this way, the temperature of the battery system is maintained within a certain temperature range, ensuring the service life of the battery system, ensuring the life requirements of the energy storage power station and the unlimited short-term discharge power requirements.

Further, the S1 specifically includes:

According to the discharge power meter of the battery system, determine the SOC _cut-off of the discharge cut-off;

Obtain the current battery power SOC0, discharge load, and discharge time Δt of the battery system, and determine whether the battery system is in the discharge state based on the SOC _cut-off .

Further, the determination of the power SOC _cut-off at the discharge cut-off specifically includes:

Obtain the minimum battery power SOC1 of the battery system when the battery system meets the discharge power;

Obtain the minimum power SOC2 allowed by the self-discharging of the battery system;

The electric quantity SOC _cut-off at the discharge cut-off is determined according to SOC1 and SOC2.

Further, the determination that the battery system is in the discharge state also includes detecting the highest temperature of the battery system during the discharge process, and the monitoring process includes: obtaining the highest temperature T _life of the battery system during the discharge process and the allowable temperature of the battery system when the battery system meets the discharge power. The maximum temperature Tmax1 determines the maximum temperature Tmax of the battery system during the discharge process.

Further, the judging whether cooling needs to be turned on during the discharge process of the battery system specifically includes:

Obtain the maximum temperature Tmax0 of the battery system at time t0, the ambient temperature Te, the discharge current of the battery system with P power within the period Δt, and the internal resistance of the battery system battery, and determine the calorific value of the battery system within the period Δt;

According to the calorific value of the battery system during the Δt period, determine the temperature rise ΔT of the battery system at the time Δt during the discharge process;

Obtain the highest temperature Tmax of this discharge process, compare the sum of the highest temperature Tmax0 of the system with the temperature rise ΔT of the battery system at time Δt during the discharge process, and the highest temperature Tmax of the battery system during this discharge process, and judge whether it is necessary according to the comparison result Turn on cooling.

Further, the acquisition of the discharge state parameters of the battery system during the discharge process specifically includes: obtaining the discharge power of the battery system at time t0, combining with the power SOC0, determining the power SOC of the battery system at time Δt during the discharge process, and determining whether the battery system is Still in the process of discharging.

Further, the S3 specifically includes:

Calculate the heat generation Q1 of the battery system itself during the period from the highest temperature of the battery system from Tmax to Tmax0+ΔT;

Calculate the heat Q2 required by the battery system's own heat capacity when the battery system has Tmax to Tmax0+ΔT;

Obtain the cooling efficiency of the battery system, combined with the heat generated by the battery system itself Q1 and the heat Q2 required by the battery system's own heat capacity;

Determine the length of time that cooling needs to be turned on;

Determine the cooling-on time according to the required cooling-on duration.

Further, the determining the cooling-on time according to the required cooling-on duration specifically includes:

t=t0+(Δt-Δt1)

t represents the cooling start time, t0 represents the discharge start time, Δt represents the discharge duration, and Δt1 represents the required cooling start time.

The second aspect of the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and operable on the processor. When the processor executes the program, a lithium-ion battery for energy storage is realized. System intelligent discharge method.

The third aspect of the present invention provides a computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, an intelligent discharge method for a lithium-ion battery system for energy storage is realized.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

1. According to the state of charge of the battery system, the discharge power and discharge time of the battery system, determine whether the battery system is in the discharge state, and determine whether the cooling needs to be turned on during the discharge process of the battery system. According to the heat generated during the discharge process of the battery system and the battery system The heat required by its own heat capacity determines the cooling time of the battery system during the discharge process. In this way, the temperature of the battery system is maintained within a certain temperature range, ensuring the service life of the battery system, ensuring the life requirements of the energy storage power station and the unlimited short-term discharge power requirements.

2. When the energy storage lithium-ion battery system is discharging, based on the current battery system SOC of the battery system, the highest temperature Tmax of the battery system, the discharge power, and the internal resistance parameters of the battery system, determine the remaining charge of the battery system during the discharge process and the temperature rise of the battery system , based on the temperature rise of the battery system, determine when the battery system is turned on for cooling, so as to ensure that the battery system meets the discharge power requirements and the long-term battery system life requirements.

Description of drawings

In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention. Therefore, it should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained according to these drawings without creative work. In the attached picture:

FIG. 1 is a flowchart of a discharge method in an embodiment of the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the examples and accompanying drawings. As a limitation of the present invention.

When designing an energy storage power station, the manufacturer generally sets the highest temperature corresponding to a charging/discharging battery system. If the temperature exceeds this temperature, the discharge power of the battery system will directly drop to 0. Using it above this temperature may cause the risk of thermal runaway or It is said that the life decay is abnormally fast; at the same time, when the energy storage power station is designed, it usually has a service life of 10 years or even longer, corresponding to the manufacturer will also give a temperature, this temperature refers to the cycle life temperature of the battery system, That is, in order to ensure that you have 10 years or even longer, the battery system is not allowed to exceed this temperature value when it is discharging. After exceeding this temperature value, there is no way to guarantee the 10-year service life, resulting in early decommissioning of the energy storage power station (involving money); combining 1 and 2, when discharging, it is required to ensure the discharge power of the battery system (demand load on the grid side) and the battery system's own life and safety requirements, which will require the battery system to be discharged during the discharge process The temperature in the battery cannot exceed the value given by the manufacturer; this patent is based on this, an algorithm developed so that no matter how much the demand load (power) on the grid side is, the energy storage power station will be based on the current ambient temperature, battery System SOC, the highest temperature of the battery system, etc., calculate when to turn on the cooling, so as to maintain the temperature of the battery system within the required temperature range during the entire discharge process, so that the power required by the battery system discharge can be guaranteed, and the battery can also be guaranteed. the useful life of the system;

Example 1

As shown in Figure 1, the first aspect of this implementation provides an intelligent discharge method for a lithium-ion battery system for energy storage, including the following specific steps:

S1. Obtain the state of charge of the battery system, the discharge power and discharge time of the battery system, and determine whether the battery system is in the discharge state;

S2. Obtain the temperature state parameters and discharge state parameters of the battery system during the discharge process, and determine whether cooling needs to be turned on during the discharge process of the battery system;

S3. Obtain the calorific value of the battery system during the Δt period during the discharge process and the heat required by the battery system's own heat capacity, and determine the cooling time of the battery system during the discharge process.

According to the state of charge of the battery system, the discharge power and discharge time of the battery system, determine whether the battery system is in the discharge state, and determine whether the cooling needs to be turned on during the discharge process of the battery system, according to the heat generated during the discharge process of the battery system and the heat of the battery system itself To determine the heat required for capacity, and determine the cooling time that needs to be turned on during the discharge process of the battery system. In this way, the temperature of the battery system is maintained within a certain temperature range, ensuring the service life of the battery system, ensuring the life requirements of the energy storage power station and the unlimited short-term discharge power requirements.

In some possible embodiments, S1 specifically includes:

According to the discharge power meter of the battery system, determine the SOC _cut-off of the discharge cut-off;

Obtain the current battery power SOC0, discharge load and discharge time Δt of the battery system, and determine whether the battery system is in the discharge state based on the SOC _cut-off , that is, SOC0-SOC _cut-off -P*Δt>0, the battery system is in the discharge state.

In some possible embodiments, determining the SOC _cut-off when the discharge cut-off specifically includes:

Obtain the minimum battery power SOC1 of the battery system when the battery system meets the discharge power;

Obtain the minimum power SOC2 allowed by the self-discharging of the battery system;

According to SOC1 and SOC2, the electric quantity SOC _cutoff at the time of discharge cutoff is determined, SOC _cutoff =max{SOC1, SOC2}.

In some possible embodiments, after determining that the battery system is in the discharge state, it also includes detecting the highest _temperature of the battery system during the discharge process. The maximum temperature Tmax1 of the battery system determines the maximum temperature Tmax of the discharge process of the battery system, Tmax=min{Tmax1, T _life }.

In some possible embodiments, judging whether cooling needs to be turned on during the discharge process of the battery system includes:

Obtain the maximum temperature Tmax0 of the battery system at time t0, the ambient temperature Te, the discharge current of the battery system with P power within the period Δt, and the internal resistance of the battery system battery, and determine the calorific value of the battery system within the period Δt;

According to the calorific value of the battery system during the Δt period, determine the temperature rise ΔT of the battery system at the time Δt during the discharge process;

Obtain the highest temperature Tmax of this discharge process, compare the sum of the highest temperature Tmax0 of the system with the temperature rise ΔT of the battery system at time Δt during the discharge process, and the highest temperature Tmax of the battery system during this discharge process, and judge whether it is necessary according to the comparison result Turn on cooling.

In some possible embodiments, the specific calculation steps include:

The temperature rise of the battery system at time t0+t1 is:

ΔT1=(Q1-dQ)/(C*m)

dQ is the heat transfer between the battery system and the environment (calibrated value);

Calculate in turn to calculate the temperature rise of the battery system at time Δt: ΔT; Tmax0 is the highest temperature of the battery system at time t0;

Comparing Tmax0+ΔT with Tmax: if Tmax0+ΔT>Tmax, it is determined that the discharge process needs to be cooled.

In some possible embodiments, obtaining the discharge state parameters of the battery system during the discharge process specifically includes: obtaining the discharge power of the battery system at time t0, combined with the power SOC0, determining the power SOC of the battery system at time Δt during the discharge process, and determining according to the discharge state parameters Whether the battery system is still in the discharge process.

In some possible embodiments, S3 specifically includes:

Calculate the heat generated by the battery system itself Q1 during the period from the highest temperature of the battery system from Tmax to Tmax0+ΔT,

Q1＝ΣI ² *R*Δt ₀ , Δt ₀ ＝1s

Calculate the heat Q2 required by the battery system's own heat capacity when the battery system has Tmax to Tmax0+ΔT,

Q2＝C*m*(Tmax0+ΔT-Tmax)

Obtain the cooling efficiency of the battery system, combined with the heat generated by the battery system itself Q1 and the heat Q2 required by the battery system’s own heat capacity,

t1=(Q1+Q2)/(P1*η)

Wherein η is cooling efficiency, and P1 is cooling power;

Determine the length of time that cooling needs to be turned on;

Determine the cooling-on time according to the required cooling-on duration.

Determining the cooling-on time according to the required cooling-on time includes:

t=t0+(Δt-Δt1)

t represents the cooling start time, t0 represents the discharge start time, Δt represents the discharge duration, and Δt1 represents the required cooling start time.

In some possible embodiments, when the discharge of the battery system ends, or the highest temperature of the battery system is less than or equal to Tmax-2°C, the cooling is ended.

The second aspect of this embodiment provides an electronic device, including a memory, a processor, and a computer program stored in the memory and operable on the processor. When the processor executes the program, an intelligent discharge of a lithium-ion battery system for energy storage is realized. method.

The third aspect of this embodiment provides a computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, an intelligent discharge method for a lithium-ion battery system for energy storage is implemented.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention and are not intended to limit the scope of the present invention. Protection scope, within the spirit and principles of the present invention, any modification, equivalent replacement, improvement, etc., shall be included in the protection scope of the present invention.

Claims (10)

1. A lithium-ion battery system intelligent discharge method for energy storage, characterized in that, comprising the following specific steps: S1. Obtain the state of charge of the battery system, the discharge power and discharge time of the battery system, and determine whether the battery system is in the discharge state; S2. Obtain the temperature state parameters and discharge state parameters of the battery system during the discharge process, and determine whether cooling needs to be turned on during the discharge process of the battery system; S3. Obtain the calorific value of the battery system during the Δt period during the discharge process and the heat required by the battery system's own heat capacity, and determine the cooling time of the battery system during the discharge process. 2. The intelligent discharge method of the lithium-ion battery system for energy storage according to claim 1, wherein the S1 specifically includes: According to the discharge power meter of the battery system, determine the SOC _cut-off of the discharge cut-off; Obtain the current battery power SOC0, discharge load, and discharge time Δt of the battery system, and determine whether the battery system is in the discharge state based on the SOC _cut-off . 3. The intelligent discharge method of the lithium-ion battery system for energy storage according to claim 1, wherein the determination of the SOC cut-off time of the discharge _cut-off specifically includes: Obtain the minimum battery power SOC1 of the battery system when the battery system meets the discharge power; Obtain the minimum power SOC2 allowed by the self-discharging of the battery system; The electric quantity SOC _cut-off at the discharge cut-off is determined according to SOC1 and SOC2. 4. The intelligent discharge method for a lithium-ion battery system for energy storage according to claim 2, wherein the determination of the discharge state of the battery system further includes detecting the highest temperature of the battery system during the discharge process, and the monitoring process includes: Obtain the maximum temperature T _{life of} the battery system during the discharge process and the maximum temperature Tmax1 allowed by the battery system when the battery system meets the discharge power, and determine the maximum temperature Tmax of the battery system during this discharge process. 5. The intelligent discharge method for a lithium-ion battery system for energy storage according to claim 1, wherein the judging whether cooling needs to be turned on during the discharge process of the battery system specifically includes: Obtain the maximum temperature Tmax0 of the battery system at time t0, the ambient temperature Te, the discharge current of the battery system with P power within the period Δt, and the internal resistance of the battery system battery, and determine the calorific value of the battery system within the period Δt; According to the calorific value of the battery system during the Δt period, determine the temperature rise ΔT of the battery system at the time Δt during the discharge process; Obtain the highest temperature Tmax of this discharge process, compare the sum of the highest temperature Tmax0 of the system with the temperature rise ΔT of the battery system at time Δt during the discharge process, and the highest temperature Tmax of the battery system during this discharge process, and judge whether it is necessary according to the comparison result Turn on cooling. 6. The intelligent discharge method of a lithium-ion battery system for energy storage according to claim 1, wherein said obtaining the discharge state parameters of the battery system during the discharge process specifically comprises: obtaining the discharge power of the battery system at time t0, combined with the power SOC0 , determine the SOC of the battery system at time Δt during the discharge process, and determine whether the battery system is still in the discharge process according to the discharge state parameters. 7. The intelligent discharge method of the lithium-ion battery system for energy storage according to claim 1, wherein said S3 specifically includes: Calculate the heat generation Q1 of the battery system itself during the period from the highest temperature of the battery system from Tmax to Tmax0+ΔT; Calculate the heat Q2 required by the battery system's own heat capacity when the battery system has Tmax to Tmax0+ΔT; Obtain the cooling efficiency of the battery system, combined with the heat generated by the battery system itself Q1 and the heat Q2 required by the battery system's own heat capacity; Determine the length of time that cooling needs to be turned on; Determine the cooling-on time according to the required cooling-on duration. 8. The intelligent discharge method of the lithium-ion battery system for energy storage according to claim 1, wherein the determination of the cooling start time according to the required cooling start time specifically includes: t=t0+(Δt-Δt1) t represents the cooling start time, t0 represents the discharge start time, Δt represents the discharge duration, and Δt1 represents the required cooling start time. 9. An electronic device comprising a memory, a processor, and a computer program stored on the memory and operable on the processor, wherein the processor implements any of claims 1 to 8 when executing the program. An intelligent discharge method for a lithium-ion battery system for energy storage described in the item. 10. A computer-readable storage medium, on which a computer program is stored, characterized in that, when the program is executed by a processor, a lithium-ion battery system for energy storage according to any one of claims 1 to 8 is realized Smart discharge method.

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