METHOD AND APPARATUS FOR COLLECTING VOLTAGE DIFFERENTIAL PARAMETERS OF INDIVIDUAL BATTERY CELLS IN BATTERY PACK

• US 20130245974A1
• Filed: 08/15/2011
• Published: 09/19/2013
• Est. Priority Date: 11/09/2010
• Status: Active Grant

• Current Assignee: Sunwoda Electronic Company Limited
• Original Assignee: Sunwoda Electronic Company Limited
• Inventors: Zheng, Weiwei
• Granted Patent: US 9,417,289 B2
• Time in Patent Office: Days
• US Class Current: 702/63
• CPC Class Codes: G01R 19/16542 for batteries charge condition monitoring in G01R31/36
• CPC Class Codes: G01R 31/36 Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
• CPC Class Codes: G01R 31/3835 involving only voltage measurements
• CPC Class Codes: G01R 31/396 Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery

Abstract

The invention belongs to the technical field of battery management, and in particular relates to a method and apparatus for collecting voltage differential parameters of individual battery cells in a battery pack. In the invention, a reference voltage is provided, the reference voltage is compared with an actual voltage of each individual battery cell at a same moment to obtain a relative voltage difference value between the actual voltage of each individual battery cell and the common reference voltage at the current moment; and an actual voltage difference value between the actual voltage of each individual battery cell and an actual average voltage value of the actual voltages of all individual battery cells is determined according to the relative voltage difference value, and each actual voltage difference value is used for representing the voltage differential parameter of the individual battery cell relative to a battery system.

Claims

1. A method for collecting voltage differential parameters of individual battery cells in a battery pack, wherein,

a reference voltage is provided, the reference voltage is compared with an actual voltage of each individual battery cell at a same moment to obtain a relative voltage difference value between the actual voltage of each individual battery cell and the reference voltage at the current moment;

and

an actual voltage difference value between the actual voltage of each individual battery cell and an actual average voltage value of the actual voltages of all individual battery cells is determined according to the relative voltage difference value, and each actual voltage difference value is used for representing the voltage differential parameter of the individual battery cell relative to a battery system.

2. The method for collecting voltage differential parameters of individual battery cells in a battery pack according to claim 1, wherein,

each actual voltage difference value is respectively determined according to each relative voltage difference value, specifically:

an arithmetic mean value of the relative voltage difference value between the actual voltages of all individual battery cells and the reference voltage is calculated as a mean relative voltage difference value; and

an absolute difference value between the relative voltage difference values and the mean relative voltage difference value is calculated, and each absolute difference value is used as an actual voltage difference value between the actual voltage of each individual battery cell and the mean actual voltage value.

3. The method for collecting voltage differential parameters of individual battery cells in a battery pack according to claim 1, wherein,

the actual voltage difference value between the voltage of each individual battery cell and the mean actual voltage value of the voltages of all individual battery cells is determined according to each relative voltage difference value, specifically:

the relative voltage difference value of the voltage of each individual battery cell is added with the reference voltage to obtain the actual voltage value of the voltage of each individual battery cell, respectively;

the arithmetic mean value of the actual voltage values of all individual battery cells is calculated as a mean actual voltage value; and

an absolute difference value between the actual voltage value of each individual battery cell and the mean actual voltage value is calculated as an actual voltage difference value between the actual voltage of each individual battery cell and the mean actual voltage value.

4. The method for collecting voltage differential parameters of individual battery cells in a battery pack according to claim 3, wherein,

the reference voltage is a voltage parameter changing with time, preset according to the charging/discharging status and time of the battery pack.

5. A apparatus for collecting voltage differential parameters of individual battery cells in a battery pack, comprising:

at least one comparison amplification circuit, a reference voltage source electrically connected to each of the comparison amplification circuits, and a main controller;

the reference voltage source is used for providing a reference voltage at the same moment and inputting the reference voltage to a second comparison voltage input end of each comparison amplification circuit;

the number of the comparison amplification circuits is the same as that of the individual battery cells contained in the battery pack, a first comparison voltage input end of each of the comparison amplification circuits is connected to an anode or a cathode of a individual battery cell, respectively, for collecting the voltage of each individual battery cell, the comparison amplification circuits are used for comparing the actual voltages of each individual battery cell input by the first comparison voltage input end and the second comparison voltage input end with the reference voltage to obtain a relative voltage difference value between the actual voltage of each individual battery cell and the reference voltage; and

the main controller is electrically connected with each of the comparison amplification circuits and used for determining an actual voltage difference value between the actual voltage of each individual battery cell and the mean actual voltage value of the voltages of all individual battery cells according to each relative voltage difference value.

6. The apparatus for collecting voltage differential parameters of individual battery cells in a battery pack according to claim 5, wherein,

an analog-to-digital (A/D) conversion and communication circuit is further connected in series between each of the comparison amplification circuits and the main controller;

and

the analog-to-digital (A/D) conversion and communication circuit is electrically connected with the main controller via a serial bus.

7. The apparatus for collecting voltage differential parameters of individual battery cells in a battery pack according to claim 6, wherein,

the main controller comprises a first calculation unit and a second calculation unit electrically connected, the first calculation unit is electrically connected with each of the comparison amplification circuits and used for calculating an arithmetic mean value of a relative voltage difference value between the actual voltages of all individual battery cells and the reference voltage as a mean relative voltage difference value;

and

the second calculation unit is electrically connected with each of the comparison amplification circuits and the first calculation unit, respectively, and used for calculating an absolute difference value between the relative voltage difference value and the mean relative voltage difference value as an actual voltage difference value between the actual voltage of each individual battery cell and the mean actual voltage value.

8. The apparatus for collecting voltage differential parameters of individual battery cells in a battery pack according to claim 6, wherein,

the main controller comprises a third calculation unit, a fourth calculation unit and a fifth calculation unit electrically connected;

the third calculation unit is electrically connected with an output end of each of the comparison amplification circuits and the reference voltage source, respectively, and used for adding the relative voltage difference value of the voltage of each individual battery cell with the reference voltage to obtain the actual voltage value of each individual battery cell, respectively;

the fourth calculation unit is electrically connected with the third calculation unit, and used for averaging the actual voltage values of all individual battery cells to obtain a mean actual voltage value; and

the fifth calculation unit is electrically connected with the third calculation unit and the fourth calculation unit, respectively, and used for calculating an absolute difference value between the actual voltage value of each individual battery cell and the mean actual voltage value as an actual voltage difference value between the actual voltage of each individual battery cell and the mean actual voltage value.

9. The apparatus for collecting voltage differential parameters of individual battery cells in a battery pack according to claim 8, wherein,

the reference voltage is a voltage parameter changing with time, preset according to the charging/discharging status and time of the battery pack.