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A battery cell over-discharge protection method and system

A technology for over-discharge protection and battery cells, applied in emergency protection circuit devices, electrical components, etc., can solve problems such as inability to protect battery cells, inability to reduce power protection of battery cells, and excessive power demand

Active Publication Date: 2017-11-03
BEIJING BORGWARD AUTOMOBILE CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] However, in the prior art, the maximum discharge power allowed by the BMS is only determined according to the SOC value of the power battery (battery state of charge) and the battery temperature, so the above-mentioned technical solution cannot effectively protect the battery cell from power reduction.
For example, if the current VMS allows a maximum discharge power of 20KW, the minimum cell voltage is lower than the cell threshold, and the current BMS allows a maximum discharge power of 70kw, then the calculated VMS allows a maximum discharge power of 35kw, but 35KW is still higher than the previous 20KW, so the power demand is still too high, it cannot play the role of power reduction, and cannot protect the battery cell corresponding to the lowest battery cell voltage

Method used

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  • A battery cell over-discharge protection method and system
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  • A battery cell over-discharge protection method and system

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Embodiment 1

[0038] This embodiment provides a battery cell over-discharge protection method, such as figure 2 shown, including the following steps:

[0039] S1: Take the maximum discharge power allowed by the BMS at the current moment as the first data; the smaller value of the battery discharge power at the previous moment and the maximum discharge power allowed by the BMS at the current moment is the second data.

[0040] S2: When the lowest cell voltage is higher than the cell voltage threshold, the first data is output as the maximum discharge power allowed by VMS; when the minimum cell voltage is lower than or equal to the cell voltage threshold, and the accelerator pedal flag is "1 ”, according to the second data and the adjustment coefficient A, the VMS allowable maximum discharge power is obtained and output.

[0041] In the above solution in this embodiment, the maximum discharge power allowed by the BMS at the current moment and the battery discharge power at the previous mome...

Embodiment 2

[0048] This embodiment provides a battery cell over-discharge protection system, such as image 3 As shown, it includes a data acquisition unit and a data processing unit.

[0049] The data acquisition unit uses the maximum allowable discharge power of the BMS at the current moment as the first data; the smaller value of the discharge power of the battery at the previous moment and the maximum allowable discharge power of the BMS at the current moment is the second data.

[0050] In the data processing unit, when the lowest cell voltage is higher than the cell voltage threshold, the first data is output as the maximum discharge power allowed by VMS; when the lowest cell voltage is lower than or equal to the cell voltage threshold, and the accelerator pedal flag When the bit is "1", the VMS allowable maximum discharge power is obtained and output according to the second data and the adjustment coefficient A.

[0051] The data acquisition unit can directly acquire the required ...

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Abstract

The invention provides a battery cell over-discharge protection method and system. When the lowest cell voltage is lower than the cell voltage threshold, the battery power required to maintain the current motor working state is used as the base to gradually decrease. When the minimum cell voltage exceeds the cell voltage threshold, no matter how the minimum cell voltage changes, if the accelerator pedal flag is "1", that is, if the accelerator pedal is not released, the battery power required to maintain the current motor working state is The base number changes until the accelerator pedal is released. Through the above solution of the present invention, when the lowest cell voltage is lower than the threshold value of the cell voltage, the power reduction operation can be truly realized, and the battery cells can be protected.

Description

technical field [0001] The invention relates to a battery cell over-discharge protection method and system, which are suitable for electric vehicle battery management systems. Background technique [0002] The power battery is the key component of electric vehicles and the source of power for electric vehicles. The power battery is composed of multiple battery cells. Ideally, the voltage value of each battery cell will change with the total voltage according to a certain algorithm and in step with each other. However, due to errors caused by current battery development technical conditions, material differences, manual assembly, and manual testing, it is impossible for each battery cell to achieve complete consistency. When the consistency of the battery cells is not good, some battery cells will be fully charged during charging, and some battery cells will have a deeper discharge depth than normal battery cells during discharge, that is, over-discharge occurs. As the num...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02H7/18
Inventor 王世蒙
Owner BEIJING BORGWARD AUTOMOBILE CO LTD