Lithium battery pack voltage acquisition circuit

Abstract

The utility model discloses a lithium battery pack voltage acquisition circuit, the lithium battery pack is formed by connecting a plurality of battery cells in series, the lithium battery pack voltage acquisition circuit comprises a plurality of voltage division acquisition units, the plurality of voltage division acquisition units respectively acquire the anode voltage of each battery cell, and the acquisition ends of the adjacent voltage division acquisition units are respectively connected through equalization resistors. The equalization resistor is formed by connecting one resistor or a plurality of resistors in series. According to the voltage acquisition circuit of the lithium battery pack, the acquisition ends of the adjacent voltage division acquisition units are respectively connected through the equalization resistors, and the voltage acquisition circuit is used for equalizing the power consumption among the batteries, so that the problems that the power consumption in each string of batteries is different due to different resistance voltage division, and the batteries are unbalanced after multiple times of use and circulation are solved.

Description

A lithium battery pack voltage acquisition circuit Technical Field

[0001] This utility model belongs to the field of lithium-ion battery technology, and specifically relates to a lithium battery pack voltage acquisition circuit. Background Technology

[0002] Lithium batteries have advantages such as high energy density, long service life, high rated voltage, high power handling capacity, low self-discharge rate, light weight, and strong adaptability to high and low temperatures. However, they also have disadvantages such as poor safety and the need for protection circuits to prevent overcharging, over-discharging, overcurrent, short circuit, and over-temperature protection.

[0003] The existing lithium battery protection circuit design schemes have the following problems:

[0004] During the battery sampling process, the software battery pack uses resistor voltage division sampling. Because the voltage division is different due to different resistor values, the power consumption of each battery string is different. After multiple use cycles, this will lead to battery imbalance. Summary of the Invention

[0005] The purpose of this invention is to provide a voltage acquisition circuit for a lithium battery pack to balance the power consumption among the batteries.

[0006] The technical solution of this utility model is:

[0007] A lithium battery pack voltage acquisition circuit is disclosed. The lithium battery pack is composed of multiple cells connected in series. The lithium battery pack voltage acquisition circuit includes multiple voltage divider acquisition units, which respectively acquire the positive electrode voltage of each cell. The acquisition terminals of adjacent voltage divider acquisition units are connected through equalizing resistors.

[0008] Preferably, the balancing resistor is one or more resistors connected in series.

[0009] Preferably, the plurality of voltage divider acquisition units are connected to the positive terminal of each battery cell via a switching unit.

[0010] Preferably, the voltage divider acquisition unit includes two resistors connected in series, and the node between the two resistors is the acquisition output terminal.

[0011] Preferably, the switching unit consists of two switching transistors, and the controller sequentially controls the on / off state of the two switching transistors to control the voltage divider acquisition unit to connect to the positive terminal of the corresponding battery cell.

[0012] The advantages of this utility model are:

[0013] The lithium battery pack voltage acquisition circuit of this utility model connects the acquisition terminals of adjacent voltage divider acquisition units through equalizing resistors to equalize the power consumption of each battery. This overcomes the problem that the power consumption of each battery string is different due to the different voltage division values ​​of the resistors, which can lead to battery imbalance after multiple cycles of use. Attached Figure Description

[0014] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0015] Figure 1 is a schematic diagram of the lithium battery pack voltage acquisition circuit of the embodiment. Detailed Implementation

[0016] As shown in Figure 1, the lithium battery pack voltage acquisition circuit of this embodiment is a 6-cell lithium battery pack consisting of 6 cells connected in series. The lithium battery pack voltage acquisition circuit includes 6 voltage divider acquisition units, which respectively acquire the voltage V1-V6 of the positive electrode of each cell. The 6 voltage divider acquisition units are connected to the positive electrode of each cell through a switching unit.

[0017] The voltage divider acquisition unit includes two resistors connected in series, and the node between the two resistors is the acquisition output terminal VB1-VB6.

[0018] The switching unit consists of two switching transistors. The controller controls the on / off state of the two switching transistors in sequence, and controls the voltage divider acquisition unit to connect to the positive terminal of the corresponding battery cell.

[0019] The acquisition terminals of adjacent voltage divider acquisition units are connected to each other via equalizing resistors. The equalizing resistors consist of one or more resistors connected in series. The equalizing resistor scheme in this embodiment is as follows:

[0020] The series resistance between V1 and V2 is R146=10K and R147=9.1K.

[0021] The series resistance between V2 and V3 is R139=3.9K and R145=1K.

[0022] The resistance between V3 and V4 is R138 = 2.2K.

[0023] The resistance between V4 and V5 is R137 = 1.2K;

[0024] The resistance between V5 and V6 is R136 = 750 R.

[0025] The lithium battery pack voltage acquisition circuit of this utility model connects the acquisition terminals of adjacent voltage divider acquisition units through equalizing resistors to equalize the power consumption of each battery. This overcomes the problem that the power consumption of each battery string is different due to the different voltage division values ​​of the resistors, which can lead to battery imbalance after multiple cycles of use.

[0026] The above embodiments are only for illustrating the technical concept and features of this utility model, and are intended to enable those skilled in the art to understand the content of this utility model and implement it accordingly. They should not be construed as limiting the scope of protection of this utility model. All modifications made in accordance with the spirit and essence of the main technical solution of this utility model should be included within the scope of protection of this utility model.

Claims

1. A voltage acquisition circuit for a lithium battery pack, wherein the lithium battery pack consists of 6 cells connected in series, characterized in that, The lithium battery pack voltage acquisition circuit includes six voltage divider acquisition units, which acquire the voltages V1-V6 of the positive terminals of each battery cell, respectively. The acquisition terminals of adjacent voltage divider acquisition units are connected via equalizing resistors. Each of the six voltage divider acquisition units is connected to the positive terminal of each battery cell via a switching unit. Each voltage divider acquisition unit includes two resistors connected in series, with the node between the two resistors serving as the acquisition output terminal. Each switching unit consists of two switching transistors, and the controller sequentially controls the on / off state of the two switching transistors to connect the voltage divider acquisition unit to the corresponding positive terminal of the battery cell. The equalizing resistors consist of one or more resistors connected in series: the series resistors between V1 and V2 are R146=10KΩ and R147=9.1KΩ; between V2 and V3 are R139=3.9KΩ and R145=1KΩ; between V3 and V4 are R138=2.2KΩ; between V4 and V5 are R137=1.2KΩ; and between V5 and V6 are R136=750Ω.

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