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Imbalance fault determining and balancing method for battery pack

A technology of fault determination and equalization method, which is applied in battery circuit devices, current collectors, power supply testing, etc., and can solve problems such as inability to effectively guide equalization work.

Active Publication Date: 2016-08-10
BEIJING PRIDE NEW ENERGY BATTERY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, when a battery pack failure occurs, the BMS only reports the low voltage or high voltage fault based on the inconsistency of the collected voltage, which does not reflect the cause of the fault, let alone effectively guide the subsequent equalization work

Method used

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  • Imbalance fault determining and balancing method for battery pack

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] In this example, the battery pack of the lithium iron phosphate system is tested.

[0041] First set the current direction of the battery work. Let i be the charging and discharging current. When i>0, it means charging; when i Among them, SOC t is the nuclear power state at time t, SOC 0 is the nuclear power state at the initial moment.

[0042] Then set the SOC to reach 90% as node K when charging.

[0043] Set the voltage characteristic parameter P as the cut-off voltage value at the charging end.

[0044] Combined with the performance of the lithium iron phosphate battery system, V is set to 150mV.

[0045] set p m is the average voltage of all single cells in the battery pack at node K.

[0046]When the battery pack is working, when it reaches the set node K, the parameter value P of one or several battery cells is detected for the first time s and deviation from the standard value P m Deviation reaches |P s -P m |≥150mV, then record the voltage difference...

Embodiment 2

[0074] The difference between this example and Example 1 is that

[0075] Set the voltage characteristic parameter P as the cut-off voltage value at the end of discharge.

[0076] The balanced measures taken for different types of faults determined are:

[0077] When the BMS recognizes a faulty cell with a high SOC, it chooses to balance the target cell at the end of discharge, and the equalization method is an active equalization of energy transfer type.

[0078] When the BMS identifies a faulty cell with low SOC, it chooses to balance it at the end of charging. The balancing method is the active balancing of energy transfer in the battery pack.

[0079] When the BMS recognizes that the capacity is low, if the rated capacity is too low, the battery cell must be replaced. If it is within a certain range, the battery cells with low capacity can be balanced. The equalization method is adopted at the end of discharge. Active equalization charges it.

[0080] The method of the ...

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PUM

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Abstract

The invention discloses an imbalance fault determining and balancing method for a battery pack, and the method comprises two steps: fault determining and balancing strategy. The step of fault determining comprises the steps: setting a work current direction of a battery, setting a judgment node K, a voltage characteristic parameter P, a deviation standard value Pm and a fault threshold value V, and carrying out calculation and comparison according to the fault data of voltage difference between two different working current directions of a cell, so as to classify the imbalance faults of the battery. Corresponding balancing measures are employed at the balancing strategy step according to different fault types. The method can effectively determine the type of an imbalance fault of the battery pack, employs a targeted balancing measure, improves the power performance of the battery pack, and prolongs the service life of the battery pack.

Description

technical field [0001] The invention belongs to the technical field of battery management, and in particular relates to a battery pack unbalanced fault judgment and balancing method. Background technique [0002] Electric vehicle power batteries and other energy storage devices are gradually entering the market from the initial experimental stage. In various energy storage devices, batteries are used in a way that a large number of battery cells are assembled in series and / or in parallel to form a battery pack, and a battery pack containing a large number of series and / or parallel battery cells is Affected by many uncontrollable factors, it will cause differences between battery cells, thereby reducing the power performance of the battery pack, reducing the use time of energy storage equipment, reducing the cruising range of the vehicle, and so on. Therefore, research on equilibrium has become a current hot spot in the industry. [0003] There are two main differences in t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J7/00G01R31/40
Inventor 薛慧娟李丹东
Owner BEIJING PRIDE NEW ENERGY BATTERY
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