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

Abstract

The present invention discloses an intelligent discharge method, device and medium for a lithium-ion battery system for energy storage, comprising the following specific steps: S1, obtaining the state of charge of the battery system, the discharge power and the discharge time of the battery system, and determining whether the battery system is in the discharge state; S2, obtaining the temperature state parameter and the discharge state parameter of the battery system during the discharge process, and judging whether the battery system needs to be cooled during the discharge process; S3, obtaining the heat generated in a period of Δt during the discharge process of the battery system and the heat required by the heat capacity of the battery system itself, and determining the time when the battery system needs to be cooled during the discharge process. By determining the time when the battery system needs to be cooled during the discharge process according to the heat generated during the discharge process of the battery system and the heat required by the heat capacity of the battery system itself, it is ensured that the battery system is maintained within a certain temperature range, the service life of the battery system is guaranteed, and the life requirement of the energy storage power station is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of electrochemical energy storage, and in particular to an intelligent discharge method, device and medium of a lithium-ion battery system for energy storage. Background Art

[0002] At present, the commonly used technical solutions for cooling battery systems are:

[0003] Solution 1: The lithium-ion battery system for energy storage is not equipped with a liquid cooling device. Only an air duct is set inside the battery system. An air conditioning system is set outside the battery system. The air duct is used to send external cold air into the battery system, thereby achieving cooling of the battery system during discharge.

[0004] Solution 2: A liquid cooling system is designed for the lithium-ion battery system for energy storage. When the battery system is discharging and the battery system temperature is greater than the T0 setting, the liquid cooling system is turned on to cool the battery system. When the maximum temperature Tmax of the battery system is lower than a certain temperature, the cooling is exited.

[0005] In Option 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. The cooling effect is poor. As the discharge progresses, the maximum temperature of the battery system may not be effectively controlled, causing the battery system life to decay rapidly.

[0006] Solution 2: A cooling system is configured for the lithium-ion battery system for energy storage. When the battery system is charging and discharging, when the temperature of the battery system exceeds a certain value, cooling is turned on until the battery system temperature meets the requirements. However, the cooling threshold is set to a constant value. As the battery system ages, the maximum temperature of the battery system may not be effectively controlled during the discharge process, resulting in a reduction in the discharge power of the battery system and a faster attenuation of the battery system life. If the cooling threshold is set too low, it may cause a waste of cooling energy. Summary of the invention

[0007] The technical problem to be solved by the present invention is that the battery system will generate heat and rise in temperature 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, device and medium for a lithium-ion battery system for energy storage, and determine whether the battery system is in a discharge state according to the state of charge of the battery system, the discharge power of the battery system and the discharge time, and judge whether the battery system needs to be cooled during the discharge process. According to the heat generated during the discharge process of the battery system and the heat required by the battery system's own heat capacity, determine the time when the battery system needs to be cooled 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, the life requirements of the energy storage power station and the requirements of unlimited short-term discharge power.

[0008] The present invention is achieved through the following technical solutions:

[0009] The first aspect of the present invention provides an intelligent discharge method for a lithium-ion battery system for energy storage, comprising the following specific steps:

[0010] S1. Obtain the state of charge, discharge power and discharge time of the battery system, and determine whether the battery system is in the discharge state;

[0011] 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;

[0012] S3. Obtain the heat generated during the Δt period of the battery system during the discharge process and the heat required by the battery system's own heat capacity, and determine the time when the battery system needs to start cooling during the discharge process.

[0013] The present invention determines whether the battery system is in the discharge state according to the state of charge, discharge power and discharge time of the battery system, judges whether cooling is required during the discharge process of the battery system, and determines the time when cooling is required during the discharge process of the battery system according to the heat generated during the discharge process of the battery system and the heat required by the heat capacity of the battery system itself. Thus, the temperature of the battery system is maintained within a certain temperature range, the service life of the battery system is guaranteed, the service life requirements of the energy storage power station and the requirement of unlimited short-term discharge power are guaranteed.

[0014] Furthermore, the S1 specifically includes:

[0015] According to the battery system discharge power table, determine the SOC at the end of discharge. 截止 ;

[0016] Get the current battery system power SOC0, discharge load and discharge time Δt, combined with SOC 截止 Determine if the battery system is in discharge mode.

[0017] Furthermore, the determination of the amount of electricity SOC at the time of discharge cut-off 截止 Specifically include:

[0018] Obtain the minimum power SOC1 of the battery system when the battery system meets the discharge power;

[0019] Obtain the minimum power SOC2 allowed by the battery system's self-discharge;

[0020] Determine the SOC at the end of discharge based on SOC1 and SOC2 截止 .

[0021] Furthermore, after determining that the battery system is in the discharge state, the method further includes detecting the highest temperature of the battery system during the discharge process. The monitoring process includes: obtaining the highest temperature T during the discharge process of the battery system life The maximum temperature Tmax of the battery system during this discharge process is determined by the maximum temperature Tmax1 allowed by the battery system when the battery system meets the discharge power.

[0022] Furthermore, the determination of whether cooling needs to be turned on during the discharge process of the battery system specifically includes:

[0023] Obtain the maximum temperature Tmax0 of the battery system at time t0, the ambient temperature Te, the discharge current of the battery system at power P in the period Δt, and the internal resistance of the battery system, and determine the heat generated by the battery system in the period Δt;

[0024] According to the heat generated by the battery system during the Δt period, determine the temperature rise ΔT of the battery system at the time Δt during the discharge process;

[0025] Obtain the highest temperature Tmax of this discharge process, compare the sum of the system's highest temperature Tmax0 and the temperature rise ΔT of the battery system at time Δt during the discharge process with the highest temperature Tmax of the battery system during this discharge process, and determine whether cooling needs to be turned on based on the comparison result.

[0026] Furthermore, 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, combining 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 discharge process according to the discharge state parameters.

[0027] Furthermore, the S3 specifically includes:

[0028] Calculate the heat Q1 generated by the battery system itself during the period from the highest temperature Tmax to Tmax0+ΔT;

[0029] Calculate the heat Q2 required by the battery system's own heat capacity when the battery system has a range from Tmax to Tmax0+ΔT;

[0030] Obtain the cooling efficiency of the battery system, combining the heat generated by the battery system itself Q1 and the heat required by the battery system's own heat capacity Q2;

[0031] Determine the required cooling time;

[0032] Determine the cooling start time according to the required cooling start time.

[0033] Further, determining the cooling start time according to the required cooling start time specifically includes:

[0034] t=t0+(Δt-Δt1)

[0035] 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.

[0036] A second aspect of the present invention provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, an intelligent discharge method for a lithium-ion battery system for energy storage is implemented.

[0037] A third aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements an intelligent discharge method for a lithium-ion battery system for energy storage.

[0038] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0039] 1. According to the state of charge, discharge power and discharge time of the battery system, determine whether the battery system is in the discharge state, judge whether the battery system needs to be cooled during the discharge process, and determine the time when the battery system needs to be cooled during the discharge process according to the heat generated during the discharge process of the battery system and the heat required by the battery system's own heat capacity. In this way, the temperature of the battery system is maintained within a certain temperature range, ensuring the service life of the battery system, the life requirements of the energy storage power station and the requirement of unlimited short-term discharge power.

[0040] 2. When the energy storage lithium-ion battery system is discharging, the remaining charge of the battery system and the temperature rise of the battery system during the discharge process are determined based on the current battery system SOC, the maximum temperature Tmax of the battery system, the discharge power, and the internal resistance parameters of the battery system. Based on the temperature rise of the battery system, it is determined when the battery system should start cooling, thereby ensuring that the battery system meets the discharge power requirement and the long-term battery system life requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without creative work. In the drawings:

[0042] Figure 1 4 is a flow chart of a discharge method in an embodiment of the present invention. DETAILED DESCRIPTION

[0043] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0044] When designing an energy storage power station, the manufacturer will generally give a maximum temperature corresponding to the charging / discharging battery system. If this temperature is exceeded, the discharge power of the battery system will drop directly to 0. Using it at a temperature exceeding this temperature may bring about the risk of thermal runaway or abnormally rapid life decay. At the same time, when designing an energy storage power station, it is generally designed for a service life of 10 years or even longer, and the manufacturer will also give a temperature corresponding to it. This temperature refers to the cycle life temperature of the battery system. That is, in order to ensure that you can use the battery system for 10 years or even longer, the battery system is not allowed to exceed this temperature value when discharging. If this temperature value is exceeded, the 10-year service life cannot be guaranteed, resulting in the early retirement of the energy storage power station (involving money); Combining 1 and 2, it is required that during discharge, the discharge power of the battery system (grid-side demand load) and the battery system's own life and safety requirements must be guaranteed, which requires that the temperature of the battery system during the discharge process cannot exceed the value given by the manufacturer; this patent is based on an algorithm developed in this way, so that no matter how much the grid-side demand load (power) is, the energy storage power station will calculate when to start cooling based on the current ambient temperature, battery system SOC, battery system maximum temperature, etc., so as to maintain the temperature of the battery system within the required temperature range during the entire discharge process, thereby ensuring the power required for the battery system to discharge and also ensuring the service life of the battery system;

[0045] Example 1

[0046] like Figure 1 As shown, the first aspect of this embodiment provides an intelligent discharge method for a lithium-ion battery system for energy storage, comprising the following specific steps:

[0047] S1. Obtain the state of charge, discharge power and discharge time of the battery system, and determine whether the battery system is in the discharge state;

[0048] 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;

[0049] S3. Obtain the heat generated during the Δt period of the battery system during the discharge process and the heat required by the battery system's own heat capacity, and determine the time when the battery system needs to start cooling during the discharge process.

[0050] According to the state of charge, discharge power and discharge time of the battery system, determine whether the battery system is in the discharge state, judge whether the cooling needs to be turned on during the discharge process of the battery system, and determine the time when 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 required by the battery system's own heat capacity. In this way, the temperature of the battery system is maintained within a certain temperature range, ensuring the service life of the battery system, the life requirements of the energy storage power station and the requirements of unlimited short-term discharge power.

[0051] In some possible embodiments, S1 specifically includes:

[0052] According to the battery system discharge power table, determine the SOC at the end of discharge. 截止 ;

[0053] Get the current battery system power SOC0, discharge load and discharge time Δt, combined with SOC 截止 Determine whether the battery system is in discharge state, that is, SOC0-SOC 截止 -P*Δt>0, the battery system starts discharging state.

[0054] In some possible embodiments, the SOC at the time of discharge termination is determined. 截止 Specifically include:

[0055] Obtain the minimum power SOC1 of the battery system when the battery system meets the discharge power;

[0056] Obtain the minimum power SOC2 allowed by the battery system's self-discharge;

[0057] Determine the SOC at the end of discharge based on SOC1 and SOC2 截止 , SOC 截止 =max{SOC1, SOC2}.

[0058] In some possible embodiments, after determining that the battery system is in the discharge state, the highest temperature of the battery system during the discharge process is detected. The monitoring process includes: obtaining the highest temperature T during the discharge process of the battery system life and the maximum temperature Tmax1 allowed by the battery system when the battery system meets the discharge power, determine the maximum temperature Tmax of the battery system during this discharge process, Tmax=min{Tmax1, T life}.

[0059] In some possible embodiments, determining whether cooling needs to be turned on during the discharge process of the battery system specifically includes:

[0060] Obtain the maximum temperature Tmax0 of the battery system at time t0, the ambient temperature Te, the discharge current of the battery system at power P in the period Δt, and the internal resistance of the battery system, and determine the heat generated by the battery system in the period Δt;

[0061] According to the heat generated by the battery system during the Δt period, determine the temperature rise ΔT of the battery system at the time Δt during the discharge process;

[0062] Obtain the highest temperature Tmax of this discharge process, compare the sum of the system's highest temperature Tmax0 and the temperature rise ΔT of the battery system at time Δt during the discharge process with the highest temperature Tmax of the battery system during this discharge process, and determine whether cooling needs to be turned on based on the comparison result.

[0063] In some possible embodiments, the specific calculation steps include:

[0064] The temperature rise of the battery system at time t0+t1 is:

[0065] ΔT1=(Q1-dQ) / (C*m)

[0066] dQ is the heat exchange between the battery system and the environment (calibrated value);

[0067] Calculate in sequence to calculate the temperature rise of the battery system at time Δt: ΔT; Tmax0 is the maximum temperature of the battery system at time t0;

[0068] Compare Tmax0+ΔT with Tmax: If Tmax0+ΔT>Tmax, it is determined that cooling is required for this discharge process.

[0069] 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, combining 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 discharge process according to the discharge state parameters.

[0070] In some possible embodiments, S3 specifically includes:

[0071] Calculate the heat Q1 generated by the battery system during the period from the highest temperature Tmax to Tmax0+ΔT.

[0072] Q1=ΣI 2 *R*Δt0, Δt0=1s

[0073] Calculate the heat Q2 required by the battery system's own heat capacity when the battery system has a range from Tmax to Tmax0+ΔT.

[0074] Q2=C*m*(Tmax0+ΔT-Tmax)

[0075] Obtain the cooling efficiency of the battery system, combining the heat generated by the battery system itself Q1 and the heat required by the battery system's own heat capacity Q2,

[0076] t1=(Q1+Q2) / (P1*η)

[0077] Where η is the cooling efficiency and P1 is the cooling power;

[0078] Determine the required cooling time;

[0079] Determine the cooling start time according to the required cooling start time.

[0080] Determine the cooling start time according to the required cooling start time, including:

[0081] t=t0+(Δt-Δt1)

[0082] 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.

[0083] In some possible embodiments, cooling ends when the discharge of the battery system ends or the maximum temperature of the battery system is less than or equal to Tmax-2° C.

[0084] A second aspect of this embodiment provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, an intelligent discharge method for a lithium-ion battery system for energy storage is implemented.

[0085] A third aspect of this embodiment provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements an intelligent discharge method for a lithium-ion battery system for energy storage.

[0086] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An intelligent discharge method for a lithium-ion battery system for energy storage, characterized in that: The specific steps include: S1. Obtain the state of charge, discharge power and discharge time of the battery system, determine whether the battery system is in the discharge state, and after determining that the battery system is in the discharge state, detect the highest temperature of the battery system during the discharge process. The detection process includes: obtaining the highest temperature T during the discharge process of the battery system life and the maximum temperature Tmax1 allowed by the battery system when the battery system meets the discharge power, to determine the maximum temperature Tmax of the battery system during this discharge process; S2. Obtain the temperature state parameters and discharge state parameters of the battery system during the discharge process, and determine whether the battery system needs to be cooled during the discharge process. The specific process includes: Obtain the maximum temperature Tmax0 of the battery system at time t0, the ambient temperature Te, the discharge current of the battery system at power P in the period Δt, and the internal resistance of the battery system, and determine the heat generated by the battery system in the period Δt; According to the heat generated by 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 system's highest temperature Tmax0 and the temperature rise ΔT of the battery system at time Δt during the discharge process with the highest temperature Tmax of the battery system during this discharge process, and determine whether cooling needs to be turned on based on the comparison result; S3. Obtain the heat generated during the Δt period of the battery system during the discharge process and the heat required by the battery system's own heat capacity, and determine the time when the battery system needs to start cooling during the discharge process.

2. The intelligent discharge method of a lithium-ion battery system for energy storage according to claim 1, characterized in that: The S1 specifically includes: According to the battery system discharge power table, determine the SOC at the end of discharge. 截止 ; Get the current battery system power SOC0, discharge load and discharge time Δt, combined with SOC 截止 Determine if the battery system is in discharge mode.

3. The intelligent discharge method of the lithium-ion battery system for energy storage according to claim 2, characterized in that: Determining the SOC when the discharge is terminated 截止 Specifically include: Obtain the minimum power SOC1 of the battery system when the battery system meets the discharge power; Obtain the minimum power SOC2 allowed by the battery system's self-discharge; Determine the SOC at the end of discharge based on SOC1 and SOC2 截止 .

4. The intelligent discharge method of a lithium-ion battery system for energy storage according to claim 1, characterized in that: The obtaining of the discharge state parameter of the battery system during the discharge process specifically includes: obtaining the discharged power of the battery system at time t0, determining the power SOC of the battery system at time Δt during the discharge process in combination with the power SOC0, and determining whether the battery system is still in the discharge process according to the discharge state parameter.

5. The intelligent discharge method of a lithium-ion battery system for energy storage according to claim 1, characterized in that: The S3 specifically includes: Calculate the heat Q1 generated by the battery system itself during the period from the highest temperature Tmax to Tmax0+ΔT; Calculate the heat Q2 required by the battery system's own heat capacity when the battery system has a range from Tmax to Tmax0+ΔT; Obtain the cooling efficiency of the battery system, combining the heat generated by the battery system itself Q1 and the heat required by the battery system's own heat capacity Q2; Determine the required cooling time; Determine the cooling start time according to the required cooling start time.

6. The intelligent discharge method of the lithium-ion battery system for energy storage according to claim 5, characterized in that: Determining the cooling start time according to the 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.

7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, an intelligent discharge method for a lithium-ion battery system for energy storage is implemented as described in any one of claims 1 to 6.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, an intelligent discharge method for a lithium-ion battery system for energy storage as described in any one of claims 1 to 6 is implemented.

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