Power battery self-heating method and device and readable storage medium

Abstract

The invention discloses a power battery self-heating method and device and a readable storage medium. The method comprises the steps: acquiring the battery temperature, the current electric quantity and the capacity attenuation mean value of a power battery; acquiring corresponding charging internal resistance, discharging internal resistance and negative electrode temperature coefficient according to the battery temperature; calculating a charging current according to the charging internal resistance and the charging voltage, and calculating a discharging current according to the discharginginternal resistance and the discharging voltage; calculating pulse charging time according to the current electric quantity, the capacity attenuation mean value, the charging current and the negativeelectrode temperature coefficient; calculating pulse discharging time according to the charging current, the discharging current and the pulse charging time; carrying out charging and discharging on the power battery by taking the charging current, the discharging current, the pulse charging time and the pulse discharging time as pulse parameters, so that the power battery is self-heated, negativeelectrode lithium precipitation is not caused, the self-heated battery has no obvious capacity attenuation, and the reduction of the service life of the battery caused by cyclic charging and discharging can be avoided.

Description

technical field [0001] The present application relates to the technical field of power battery thermal management, in particular to a power battery self-heating method, device and readable storage medium. Background technique [0002] Lithium-ion power batteries use graphite as the negative electrode. When charging at low temperature, the negative electrode is prone to lithium precipitation or other side reactions, which will lead to a decrease in the cruising range of electric vehicles and even serious safety problems. Therefore, before charging the battery in low temperature conditions, the thermal management system of the battery pack will heat the battery before charging. [0003] At present, for the thermal management system for heating the battery, an external heater or self-heating technology can be used to realize it, but common external heaters such as PTC (Positive Thermal Coefficient) thermistors or liquid pipes, etc., have low heating efficiency. Low; while in t...

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Problems solved by technology

[0003] At present, for the thermal management system for heating the battery, an external heater or self-heating technology can be used to realize it, but common external heaters such as PTC (Positive Thermal Coefficient) thermistors or liquid pipes, etc., have low heating efficiency. Low; while in the prior art, the internal resistance is usually used to generate ohmic heat to achieve internal heating of the battery, such as using pulse discharge to self-heat the battery. This method needs to consume battery power and cannot be used when the power is insufficient; One way is to use repeated pulse charge and discharge to raise the battery temperature, but this method mainly determines the pulse frequency through electrochemical impedance spectroscopy, and uses the boundary voltage of lithium analysis and side reactions to determine the charge and discharge pulse amplitude. On the one hand, each frequency It is difficult to determine the lithium analysis and side reaction voltage under the condition of lithium ionization. On the other hand, the problem of battery capacity attenuation is not considered, which may lead to battery capacity attenuation and shorten battery life under repeated pulse charge and discharge conditions.

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