A method for determining battery discharge curve

Abstract

The invention discloses a method for determining a battery discharge curve, which belongs to the technical field of batteries. Use the kinematics model to describe the discharge curve under different discharge rates, and regard the discharge curve of the battery as a trajectory of a point under the action of force, assuming that the magnitude of the force F is only related to the amount of charge released, according to the mechanical formula And the discharge curves of different rates, use the battery's SOC, SOH, discharge rate and other parameters to construct the mass m relationship, so that under different discharge rates, the force received is only related to the total charge released by the battery, so according to a discharge The wire determines the discharge line at different discharge rates, SOH represents the state of health of the battery, and SOC represents the state of charge of the battery. The unknown discharge line can be determined by the known discharge curve, which can greatly reduce the test time and provide a new direction for the research of the discharge curve of the battery.

Description

Technical field [0001] The present invention belongs to the technical field of the battery, and more particularly to a method of determining a battery discharge curve. [0002] technical background [0003] At present, with the slowness of new energy vehicles, the use of batteries is increasingly frequent, and the SOC estimation of the battery is also more important. At present, most of the estimated SOC methods are based on time based on time. Method and open circuit voltage method. [0004] The maximum problem of the integration method of time is the problem of current sampling, and most of the current sensors used are small deviation values, while the Points of Points themselves are an accumulated process, which will result in the error of the previous moment. To the next moment, and the method itself does not modify the results, which will cause the estimation error of the SOC to be larger. [0005] Open circuit voltage method, in many cases, use a model to reverse the open ci...

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Problems solved by technology

[0004] The biggest problem with the ampere-hour integration method is the problem of current sampling deviation. Most of the current sensors used now have a small deviation value, and the ampere-hour integration itself is an accumulation process, which will cause the error at the previous moment to affect To the next moment, and the method itself will not correct the result, which will lead to an increasing error in the estimation of SOC

[0005] The open circuit voltage method, in many cases, uses a model to reverse the open circuit voltage of the battery based on the current and voltage of the battery. The more cost-effective model here is the 2RC model. The problem here is the relationship between the open circuit voltage and SOC. Weak correlation, especially for lithium iron phosphate batteries, during the entire discharge process, the voltage of the battery changes very little, and the small voltage difference will map a huge SOC deviation, which will lead to very inaccurate SOC estimation

The characteristic of using this method is that the richer the data in the established database, the more accurate the estimated SOC will be, but this will take a lot of time and cost

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