Method and system for balancing battery pack

Abstract

The invention discloses a method and a system for balancing a battery pack. The method includes determining a balancing way which is selected according to consistency of batteries of the battery pack, determining that the battery pack does not work, and utilizing the determined balancing way to balance the battery pack. The method and the system for balancing the battery pack select the balancing way according to the characteristics of the batteries, so that better balance can be made between system cost reducing and energy saving; and balance management among battery monomers of the battery pack can be achieved under the condition that usage of users is not influenced.

Description

technical field [0001] The invention relates to the technical field of batteries, in particular to a method and system for balancing battery packs. Background technique [0002] Today, as environmental and energy issues are becoming more and more prominent, electric energy is becoming more and more popular because of its green and environmental protection characteristics. Batteries capable of storing electrical energy have begun to be used in fields such as electrical tools and electric vehicles. Although this new energy electric vehicle can solve the problems of energy crisis and environmental crisis, it also has a development bottleneck - the battery. The power battery pack applied to electric vehicles will cause inconsistencies between battery cells due to the differences in the manufacturing and use processes. When the battery pack is charging, the monomer with a high state of charge (SOC) will reach the cut-off voltage first, thereby reducing the amount of electricity...

AI Technical Summary

Problems solved by technology

For the problems of long discharge equalization time and heat dissipation, there are other discharge equalization methods in the prior art, which use fans, super capacitors or other energy storage and energy conversion devices to replace power resistors or connect them in parallel at both ends of power resistors to increase the equalization current As well as improving heat dissipation, although this method is cleverly designed, it will greatly increase the volume of the balanced system

[0005] Active equalization saves energy, can increase battery life, and equalizes faster, but it costs more and is more difficult to implement

There is an active equalization device in the prior art, in which each battery cell of the battery pack is equipped with a DC-DC power supply. Although it can quickly balance the large-capacity lithium-ion battery, the cost is very high, and the equalization device very bulky

There is also another active equalization device in the prior art. In this device, a polarity switch group and a battery selection switch group are used to enable an isolated converter to perform equalization management on multiple batteries, thereby reducing the number of charging and discharging devices and the number of circuits. complexity, but because a charging and discharging device can only balance one of the multiple batteries at the same time, the balancing time is longer

There is also a balancing device in the prior art. In this device, energy storage inductors are used to transfer energy in the battery pack, but this device can only transfer energy to adjacent battery cells. If two batteries that need to be balanced When the cells are far apart, the equalization time will become longer, and there will be energy loss when charging and discharging the inductor at the same time, and the energy loss will be greater when the distance between the cells to be balanced is far away

[0006] In summary, active equalization and discharge equalization have their own disadvantages

Images