Battery SOC determination method and battery management system using method

Abstract

The invention relates to a battery SOC determination method and a battery management system using the method. The battery SOC determination method comprises the steps that open-circuit voltage (OCV) of a battery is measured; the measured open-circuit voltage of the battery is compared with an OCV-SOC curve so that the SOC state of the battery is determined; and the SOC value in the OCV-SOC curve is SOC based on thermodynamic quantity of state.

Description

technical field [0001] The invention relates to a method for determining battery SOC and a battery management system using the method. Background technique [0002] With the depletion of oil resources and the increasingly severe environmental problems, seeking new energy and reducing carbon emissions has become the mainstream trend in the world. Electric vehicles are one of the main development directions. The current electric vehicles can be mainly divided into HEV (Hybrid Electric Vehicle: hybrid electric vehicle), PHEV (Plug-in Hybrid Electric Vehicle: plug-in hybrid electric vehicle), EV (Electric Vehicle: pure electric vehicles) These categories can improve energy efficiency and reduce carbon emissions during vehicle driving by partially or completely using electric energy to drive vehicles. [0003] For any type of electric vehicle, multiple batteries (or battery packs) need to be installed inside as a device for storing electric energy, and how to manage the charging...

AI Technical Summary

Problems solved by technology

[0011] The above-mentioned SOC measurement system in the prior art has many technical defects in actual use, and due to these technical defects, the SOC of the battery cannot be accurately monitored in actual use. The applicant will describe these technologies in detail in the following part defect:

[0020] As mentioned above, the two major defects of the prior art have been enumerated, but the prior art also has a third major defect, that is, the BMS based on the above-mentioned technical defects 1 and 2 has a great impact on the battery during driving. Forecasts of available power are inaccurate

That is to say, the calculation method of the battery's available power determined by the above-mentioned BMS is inaccurate, and this inaccuracy comes from the above-mentioned technical defects 1 and 2. First, the obtained SOC of the battery cannot be accurately determined. It reflects the internal state of charge of the battery, and secondly, a wrong assumption is made (that is, the default range of the SOC of the battery is 0% to 100%). On the basis of these two technical defects, the BMS finally obtains The available power prediction of the battery has a considerable error, and the above error gradually increases with the cycle process of the battery, so that in the end the BMS cannot make any meaningful predictions about the battery power

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