A device and method for improving battery utilization in the charging and discharging process of series battery packs

Abstract

The invention discloses a device and a method for improving the battery utilization rate of a series battery bank in charge and discharge processes. The device comprises a plurality of groups of battery interfaces, wherein each group of battery interfaces is connected with a single battery; the battery interfaces are connected with adjacent battery interfaces through switches; the battery interfaces are sorted from left to right; the order is that the battery interfaces with odd numbers are connected with the adjacent battery interfaces with odd numbers through by-pass switches; the order is that the battery interfaces with even numbers are connected with the adjacent battery interfaces with even numbers; all switches are controlled by a control unit; and the control unit is used for detecting the closed state of each switch in real time, and controlling the switches to connect or disconnect according to battery information. According to the device and the method, the problem of the cask effect that the overall series battery bank is limited in use due to capacity recession of individual batteries in the series battery bank is solved.

Description

technical field [0001] The invention relates to a device and a method for improving the utilization rate of batteries in the charging and discharging process of series battery packs. Background technique [0002] At present, the power battery packs for electric vehicles are used in series with multiple large-capacity batteries, generally 20, 24, 60 or higher. In the process of using the batteries in series, in order to achieve the purpose of protecting the batteries, when a single battery in the battery string is discharged to the cut-off voltage, the whole set of batteries will stop using, but at this time most of the batteries are still charged. This causes the problem that the energy of the whole set of batteries cannot be fully utilized, and the above problems also exist when charging, which is often referred to as the "short board effect" in the industry. [0003] The current industry solution to this problem is to use the battery equalization module, which can solve t...

AI Technical Summary

Problems solved by technology

In the process of using the batteries in series, in order to achieve the purpose of protecting the batteries, when a single battery in the battery string is discharged to the cut-off voltage, the whole set of batteries will stop using, but at this time most of the batteries are still charged. This will cause the problem that the energy of the whole battery pack cannot be fully utilized, and the above problems also exist when charging, which is often referred to as the "short board effect" in the industry.

[0003] The current industry solution to this problem is to use the battery equalization module, which can solve the problem of inconsistent battery power, but the existing problem is: the equalization current is small, and the current equalization current of bms manufacturers in the industry can reach 10A is the best

Passive equalization refers to discharging the battery with too high power through parallel connection of resistors at both ends of the single battery. This method is generally only used during the charging process, and there is a problem of power waste caused by energy dissipation; active equalization refers to the bidirectional DCDC The module is connected to the battery and the busbar or connected between the single batteries, and the battery with low power is charged and the battery with high power is discharged. This method has the problems of small equalization current and heat generation of the equalization module.

Therefore, whether it is active equalization or passive equalization, it can only solve the problem of power inconsistency after the battery pack has been used for a long time. For a large-capacity power battery with a capacity of several hundred Ah, battery equalization cannot Prolonging the battery life within a short period of time cannot effectively solve the "short board effect"

[0005] Chinese invention patent (patent number: 201010167717.7, patent name: a battery pack equalization device and control method based on battery pack capacity utilization), mentions the method of using the battery pack equalization device to improve battery utilization, but the patent can only solve the problem of battery The utilization rate decline problem caused by the inconsistency of long-term accumulated power, but the battery utilization rate cannot be improved in a single cycle

[0006] Chinese invention patent (patent number: 201210050979.4, patent name: battery pack automatic switching method), mentioned the method of using battery pack switching to improve battery utilization, but this patent only increases battery capacity by switching parallel battery packs, and does not improve the battery pack. The utilization rate of internal single cells, and cannot solve the problem of inconsistency accumulation of cells in the battery pack

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