Battery pack charge state calculating method and calculating device

Abstract

The invention provides a battery pack charge state calculating method. The battery pack charge state calculating method comprises the following steps: a current charge state and current test temperature of a battery unit of a battery pack can be acquired; current AC impedance and current compensation voltage can be acquired according to the current charge state, the current test temperature, a predetermined AC impedance relation table, and a predetermined compensation voltage relation table; the estimation voltage of the battery unit can be calculated according to the current charge state, the current AC impedance, and the current compensation voltage; the voltage difference between the estimation voltage and the test voltage; a corrected formula, which can be satisfied by the current charge state, the current AC impedance, and the current compensation voltage, can be acquired according to the voltage difference, and the corrected value can be acquired according to the corrected formula; and the charge state of the battery pack can be acquired according to the current charge state after the correction of the battery unit. The battery pack charge state calculating method is advantageous in that the accumulated errors can be reduced, and the calculating precision of the battery charge state can be improved. The invention also provides a battery pack charge state calculating device.

Description

technical field [0001] The invention relates to the technical field of vehicles, in particular to a calculation method and a calculation device for the state of charge of a battery pack. Background technique [0002] Lithium batteries are commonly used energy supply devices in electric vehicles. Improving the estimation accuracy of the state of charge (SOC, State of Charge) of lithium batteries is a research hotspot in the field of batteries. The accuracy of SOC of lithium batteries is very important for the control of hybrid vehicles. Algorithms, as well as the safety and economy of pure electric vehicles are of great significance. At present, the SOC estimation methods of lithium batteries used in electric vehicles mainly include discharge test method, internal resistance method, open circuit voltage method, load voltage method, ampere-hour measurement method, neural network method and Kalman filter method. The current integral estimation SOC is the most widely used SOC e...

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Problems solved by technology

[0003] However, the ampere-hour metering method is an open-loop prediction method. Although the accurate estimation of the power can be realized in a short period of time, as the cumulative error increases, the estimation accuracy will become worse and worse. The battery parameters will change accordingly due to changes in factors such as the increase of the

Therefore, the indeterminate quantization of constants and errors in the calculation formula used for SOC estimation leads to inaccurate estimation of battery SOC

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