Passive balance circuit and method for battery management system

Abstract

The invention discloses a passive balance circuit and method for a battery management system. The passive balance circuit comprises a plurality of serially connected batteries, balance loops and an acquisition control circuit, wherein the balance loops are serially connected with each battery. The passive balance circuit is characterized by further comprising matching resistors, wherein the matching resistors are used for performing differential impedance matching when voltage is acquired through the acquisition control circuit; one end of the acquisition control circuit is connected with a first end of each balance loop; the other end of the acquisition control circuit is connected with a second end of each balance loop through each matching resistor, and is used for controlling power on or power off of the balance loops and acquiring the voltage; whether the balance loops are failed according to the acquired voltage. By adopting the passive balance circuit, not only is passive balance of a battery achieved, but also whether a balance switch is failed or not can be judged through the acquisition control circuit, the battery consistency can be improved, furthermore the situation that the battery exceeds the service life and is failed can be avoided if failure of the balance switch is found in time, therefore, the security of a battery pack can be ensured.

Description

technical field [0001] The invention relates to the technical field of battery management systems for electric vehicles, in particular to a passive equalization circuit and method for the battery management system. Background technique [0002] In recent years, more and more products use lithium-ion batteries as the main power source, mainly because lithium-ion batteries have the advantages of small size, high energy density, no memory effect, high cycle life, and low self-discharge rate; but at the same time, lithium-ion batteries Ion batteries have high requirements for charging and discharging. When overcharge, overdischarge, overcurrent and short circuit occur, the pressure and heat of lithium ion batteries will increase greatly, which will easily generate sparks, burn and even explode. Therefore, lithium ion batteries are without exception Both grounds are equipped with an overcharge and discharge protection circuit. With the current manufacturing level and technology ...

AI Technical Summary

Problems solved by technology

If the balance switch fails (for example, the balance switch breaks down and short circuit), it will cause the battery to be in an uncontrollable continuous discharge state

This not only fails to protect the battery and improve the consistency of the battery, but will cause greater damage to the battery, which will eventually lead to a reduction in the life, capacity and safety performance of the entire battery module.

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