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Equalization circuit and equalization method of lithium ion battery pack

A technology for lithium-ion battery packs and lithium-ion batteries, applied in battery circuit devices, circuit devices, collectors, etc., can solve problems such as unbalanced battery cells and reduced battery life, and achieve good anti-seismic effects, stability, and extended The effect of improving service life and balancing efficiency

Active Publication Date: 2012-10-31
HARBIN INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The present invention aims to solve the problem that the imbalance between the battery cells in the existing battery pack leads to the reduction of battery life, thereby providing a lithium-ion battery pack equalization circuit and equalization method

Method used

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  • Equalization circuit and equalization method of lithium ion battery pack
  • Equalization circuit and equalization method of lithium ion battery pack
  • Equalization circuit and equalization method of lithium ion battery pack

Examples

Experimental program
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specific Embodiment approach 1

[0021] Specific implementation mode 1. Combination Figure 1 to Figure 2 Describe this specific method, a lithium-ion battery pack equalization circuit, a lithium-ion battery pack 1 is composed of N lithium-ion batteries connected in series, the lithium-ion battery pack is in a static state during operation, and N is a positive value greater than or equal to 2 Integer; it includes relay network 3, No. 1 input bus 41, No. 2 input bus 42, No. 1 output bus 51, No. 2 output bus 52, No. 1 reversing switch 61, No. 2 reversing switch 62, microcontroller 7 , forward converter 8 and voltage acquisition circuit;

[0022] The positive pole of the lithium-ion battery pack 1, the N-2 common terminals and the negative poles are the N signal output terminals of the lithium-ion battery pack 1; the common terminal refers to the connection point between two adjacent lithium-ion batteries, and the relay network 3 is composed of 2N relays; the relay network 3 is used to connect the two ends of a...

specific Embodiment approach 2

[0026] Specific embodiment two, combine image 3 Describe this specific embodiment, the difference between this specific embodiment and a lithium-ion battery pack equalization circuit described in specific embodiment 1 is that the forward converter 8 includes a high SOC battery V1 in the group, a diode D, and a main switch tube SR -Q, transformer B, No. 1 switch tube SR-Q1, No. 2 switch tube SR-Q2, energy storage inductor L, sampling resistor R, capacitor C, low SOC battery V2 in the group, current sampling unit 81, voltage sampling unit 82 and PWM drive control circuit 83;

[0027]The positive terminal of the high SOC battery V1 in the group is connected to the cathode of the diode D and one end of the primary side of the transformer B at the same time; the negative terminal of the power supply of the high SOC battery V1 in the group is connected to the anode of the diode D and one end of the main switch SR-Q at the same time connected; the other end of the main switching tu...

specific Embodiment approach 3

[0028] Specific embodiment three, combine Figure 4 Describe this specific embodiment. The difference between this specific embodiment and the balancing circuit for a lithium-ion battery pack described in the second specific embodiment is that it also includes an overcurrent protection circuit, and the overcurrent protection circuit includes a current feedback unit 91, The overcurrent value setting unit 92, the comparator 93, the RS flip-flop 94 and the main switching tube integrated drive control chip 95, the current feedback unit 91 collects the charging current signal of the battery pack through the sampling resistor R, and the current feedback unit 91 The value output end is connected with an input end of comparator 93; The overcurrent value output end of overcurrent value setting unit 92 is connected with the other input end of comparator 93; The output end of described comparator 93 is connected with RS flip-flop 94 The S input end of the RS flip-flop 94 is connected to ...

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Abstract

An equalization circuit and an equalization method of a lithium ion battery pack aim at resolve the problem of low battery service life caused by the fact that battery single bodies in the existing battery pack are not equalized. The method and the circuit can automatically conduct equalization in the battery pack when batteries are statically placed to enable electric quality of each battery single body to be kept in an allowed range and prolong service life of the batteries. The circuit and the method have the advantage that an equalization structure of single body to single body can improve equalization time and reduce equalization time. Adjustment of the equalization current adopts closed loop control to achieve the effect that charging current is constant, and energy flowing in the equalization period can be better estimated. Simultaneously, the circuit can enter the constant voltage mode to prevent overcharge when the upper limit voltage is achieved. Addition of a synchronous rectification circuit reduces connection consumption and improves equalization efficiency. A protection mechanism can effectively work continuously under the circumstances of overcurrent, short circuit and over heat and ensures safe working of an equalizer. The circuit and the method are suitable for electric bed equalization of the lithium ion battery pack.

Description

technical field [0001] The invention relates to a battery balancing circuit and a balancing method. Background technique [0002] A battery pack consists of many battery cells connected in series or in parallel and then in series. Due to factors such as manufacturing process, battery aging, different battery temperature, and internal resistance changes of these battery cells, the battery pack will appear unbalanced among the battery cells after a period of charging and discharging cycles. If you continue to use the battery pack, the The discharge capacity will be determined by the battery with the smallest capacity, so the battery with the smallest capacity is prone to over-discharge, resulting in irreversible damage to the battery cells, which in turn affects the life of the series battery pack. Contents of the invention [0003] The invention aims to solve the problem that the battery life is reduced due to the unbalance among the battery cells in the existing battery p...

Claims

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Application Information

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IPC IPC(8): H02J7/00
Inventor 朱春波孙金磊逯仁贵魏国郭尧
Owner HARBIN INST OF TECH
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