CN212323065U - Active equalization circuit for gradient utilization of retired power battery - Google Patents

Abstract

The utility model discloses an initiative equalizer circuit that retired power battery echelon utilized, including data acquisition module, main control unit MCU, data acquisition module is arranged in gathering power battery each free voltage and current data respectively, and main control unit MCU is connected to its output, the circuit still includes PWM drive circuit, two-way DCDC equalizer module, electric capacity equalizer module, switch array, PWM drive circuit is connected to main control unit MCU's output, PWM drive circuit's output is connected to the switch array for the closure and the disconnection of control switch array, every two-way DCDC equalizer module both ends and electric capacity equalizer module are connected respectively to battery monomer positive negative pole, the switch array is used for controlling break-make between battery monomer and the two-way DCDC equalizer module respectively and break-make between battery monomer and the electric capacity equalizer module. The invention has the advantages that: the circuit has simple structure and reliable balance, and can quickly balance a plurality of power battery packs connected in series at high capacity level.

Description

Active equalization circuit for gradient utilization of retired power battery

Technical Field

The utility model relates to a power battery recycle field, in particular to initiative equalizer circuit that retired power battery dedication word utilized.

Background

When the power battery for the new energy electric vehicle is used for a certain time or is circulated for a certain number of times, the capacity or power characteristic of the power battery is obviously declined, the requirement for the vehicle cannot be met, and the power battery needs to be retired from the vehicle. However, the retired power battery still has great residual value, and the capacity and power of the retired power battery can still meet the requirements of other energy storage occasions with low power requirements, so that the retired power battery can be utilized in a gradient manner.

The main reason for safety problems of retired power batteries during echelon utilization focuses on the charge and discharge link. When the retired power battery is used in a echelon mode, even though thousands of batteries are not used in an automobile, tens of batteries or hundreds of batteries are generally used, certain difference exists between every two batteries due to the restriction of production technology and production materials, and the difference between the retired batteries is more obvious. The difference of the capacities easily causes an unbalanced phenomenon, thereby causing problems of overcharge, overdischarge and the like, so to perform echelon utilization on the retired power battery, the safety problem must be solved first, and the core of solving the safety problem is mainly to solve the unbalanced phenomenon.

The existing equalization circuit is divided into active equalization and passive equalization, the passive equalization is mainly applied to scenes with low string number and low capacity, the equalization is realized mainly by depending on energy consumption, and the consumed time is long; the general active equalization has strong pertinence, and usually has a good equalization effect on a certain unbalanced state, but the effect on processing the unbalanced phenomenon of other situations is not satisfactory, and the equalization circuit in the prior art cannot adapt to the power batteries which are connected in series and recycled at a large capacity level, and the equalization time of the equalization circuit in the prior art can be very long, so that the equalization circuit in the prior art cannot better adapt to the recycling of the retired batteries.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to overcome prior art not enough, provide an initiative equalizer circuit that retired power battery echelon utilized for to the equilibrium of the recycle in-process of the power battery group of large capacity rank, many series connections, possible quick equilibrium.

In order to achieve the purpose, the invention adopts the technical scheme that: the utility model provides an initiative equalizer circuit that retired power battery echelon utilized, includes data acquisition module, main control unit MCU, data acquisition module is arranged in gathering power battery each free voltage and current data respectively, and main control unit MCU is connected to its output, the circuit still includes PWM drive circuit, two-way DCDC equalizer module, electric capacity equalizer module, switch array, PWM drive circuit is connected to main control unit MCU's output, PWM drive circuit's output is connected to switch array for the closure and the disconnection of control switch array, every two-way DCDC equalizer module both ends and electric capacity equalizer module are connected respectively to battery monomer positive negative pole, switch array is used for controlling the break-make between battery monomer and the two-way DCDC equalizer module respectively and the break-make between battery monomer and the electric capacity equalizer module.

The switch array comprises a switch tube array used for controlling the on-off of the battery monomers and the bidirectional DCDC balancing module, the switch tube array is composed of a plurality of switch tubes, two adjacent battery monomers are respectively connected with the bidirectional DCDC balancing module and used for balancing the adjacent battery monomers through the balancing module, each battery monomer corresponds to one switch tube, and the switch tubes are connected between the battery monomers and the bidirectional DCDC balancing module in series.

The switch array further comprises a relay array, the relay array is used for controlling the connection and disconnection between the single battery and the capacitance balancing module, the relay array comprises a plurality of relays, the two ends of the capacitance balancing module are connected to the two ends of each single battery through the relays respectively, and the control end of each relay is connected with the PWM driving circuit.

The utility model has the advantages that: the circuit structure is simple, the balance is reliable, and the balance in the recycling process of the power battery pack with large capacity and multiple series connection can be realized quickly; two equalization modules are adopted to respectively realize equalization, the topology of the equalization structure is reliable, and the equalization time can be shortened.

Drawings

The contents of the expressions in the various figures of the present specification and the labels in the figures are briefly described as follows:

FIG. 1 is a schematic block diagram of an equalization circuit of the present invention;

fig. 2 is a specific circuit diagram of the equalizing circuit of the present invention.

Detailed Description

The following description of preferred embodiments of the invention will be made in further detail with reference to the accompanying drawings.

This application adopts the data such as the voltage of collection module to the battery, electric current, temperature to gather, then pass to control chip MCU, carry out battery SOC's estimation through MCU, find out which economize on electricity battery electric quantity is the highest or minimum, if the battery that the electric quantity is on the high side and on the low side is adjacent, just give signal control PWM drive circuit drive switch array and make the work of the Buck-Boost equalizer circuit that corresponding battery monomer corresponds, realize the equilibrium, if the battery that the electric quantity is on the high side and on the low side is not adjacent, then drive the work of flying capacitor equalizer module, realize the equilibrium. The specific schematic block diagram 1 is as follows:

the active equalization circuit comprises a data acquisition module and a Main Control Unit (MCU), wherein the data acquisition module is used for respectively acquiring voltage and current data of each battery monomer in a power battery, the output end of the data acquisition module is connected with the MCU, the circuit further comprises a Pulse Width Modulation (PWM) driving circuit, a bidirectional direct current (DCDC) equalization module, a capacitance equalization module and a switch array, the output end of the MCU is connected with the PWM driving circuit, the output end of the PWM driving circuit is connected to the switch array and used for controlling the switch array to be closed and disconnected, each battery monomer positive electrode and negative electrode are respectively connected with two ends of the bidirectional DCDC equalization module and the capacitance equalization module, and the switch array is used for respectively controlling the connection and disconnection between the battery monomer and the bidirectional DCDC equalization module and the connection and disconnection between the battery monomer and the capacitance equalization module.

The data acquisition module includes voltage current sensor temperature sensor etc for gather data such as the free voltage current temperature of every battery in the battery package, and transmit to main control unit MCU, main control unit MCU is the core, and its processing control who mainly realizes data etc. can often directly adopt BMS to realize or the controller is commonly used to realize, like 51 series singlechip etc.. The PWM driving circuit is used for controlling the switch array to be switched on and off.

The switch array comprises a switch tube array used for controlling the on-off of the battery monomers and the bidirectional DCDC balancing module, the switch tube array is composed of a plurality of switch tubes, two adjacent battery monomers are respectively connected with the bidirectional DCDC balancing module and used for balancing between the adjacent battery monomers through the balancing module, each battery monomer corresponds to one switch tube, and the switch tubes are connected between the battery monomers and the bidirectional DCDC balancing module in series.

The switch array further comprises a relay array, the relay array is used for controlling on-off between the single battery and the capacitance balancing module, the relay array comprises a plurality of relays, two ends of the capacitance balancing module are connected to two ends of each single battery through the relays respectively, and each control end of each relay is connected with the PWM driving circuit.

The main control unit MCU respectively collects the voltage and current data of each battery monomer through the data collection module, and calculates the SOC of each battery monomer. And the MCU performs balancing operation on the single batteries according to the calculated SOC of each single battery. The specific equilibrium control principle is as follows:

the main control unit MCU respectively acquires voltage and current data of each battery monomer in the power battery through the data acquisition module, and calculates the SOC of each battery monomer according to the voltage and current data; judging the battery monomer with the highest electric quantity and the battery monomer with the lowest electric quantity according to the calculated SOC of each battery monomer; judging whether to enter the cell balancing according to the starting condition of the cell balancing; and solving the average value of the SOC of the single battery, calculating whether the difference value between the maximum electric quantity SOC and the average value of the SOC and the difference value between the minimum electric quantity SOC and the average value of the SOC are larger than a preset threshold value, and judging to enter the single battery equalization if any difference value is larger than the preset threshold value. Controlling a bidirectional DCDC balancing module or a capacitance balancing module to balance the battery monomers with the highest electric quantity and the lowest electric quantity; and judging whether two adjacent battery monomers exist between the battery monomer with the highest electric quantity and the battery monomer with the lowest electric quantity, if so, controlling the bidirectional DCDC balancing module to balance the two battery monomers, and if not, controlling the capacitance balancing module to balance the two battery monomers. And after the balance is finished, recalculating the average SOC, calculating the difference value between the maximum SOC and the average SOC and the difference value between the minimum SOC and the average SOC, and judging that the balance finishing condition is met when the difference values are smaller than a preset threshold value.

As shown in fig. 2, the structure of the switch array is described by taking three batteries connected in series as an example, the switch array includes a switching tube MOS and a relay K, in this application, the bidirectional DCDC balancing module is implemented by using an inductor L, and the capacitor balancing module is a capacitor C. The battery cells V1, V2 and V3 are connected in series to form a battery pack, the anode of the battery cell V1 is connected with the S pole of the MOS1, the D pole of the MOS1 is connected with the cathode of the V1 through L1, the D pole of the MOS1 is connected with the D pole of the MOS2, and the S pole of the MOS2 is connected with the cathode of the V2; the negative electrode of V2 is connected with the D electrode of MOS3 through inductor L2, and the S electrode of MOS3 is connected with the positive electrode of V2; the D pole of MOS3 is connected with the D pole of MOS4, and the S pole of MOS4 is connected with the negative pole of V3. The G electrodes of the MOS1, the MOS2, the MOS3 and the MOS4 are all connected with the MCU through a PWM driving circuit and used for receiving driving signals. The positive electrode of the V1 is connected with the normally open contact of the K1 through the normally open contact of the K3, the normally open contact of the K1 is connected with one end of the capacitor C, the negative electrode of the V1 is connected with the normally open contact of the K2 through the normally open contact of the K6, and the normally open contact of the K2 is connected with the other end of the capacitor C; the negative electrode of V2 is connected to the normally open contact of K1 through the normally open contact of capacitor K4, and the negative electrode of V3 is connected to the normally open contact of K2 through the normally open contact of switch K5.

The control principle of the above switch array: when the two adjacent batteries are judged to be balanced, if the inconsistency of the battery pack exceeds the limit value and UV3 is greater than UV2 as shown in FIG. 2, the Buck-Boost balancing circuit is started, so that V3 is discharged and V2 is charged. In the discharging stage of V3, a PWM driving circuit sends out a control signal, an MOS4 is closed, and electric energy is converted into magnetic energy to be stored in an inductor L _ 2; and in the charging stage of V2, the MOS3 is disconnected, the L _2, the B2 and the MOS3 form a discharging loop, and the charging is ended until the UL _2 is not enough to overcome the forward conducting voltage of the parasitic diode of the UB2 and the MOS 3.

When two non-adjacent batteries are equalized, as shown in fig. 2, if the inconsistency of the battery pack exceeds the limit value, and the UV1 is greater than the UV3, the flying capacitor equalization module is started, so that the V1 is discharged and the V3 is charged. In the discharging stage of V1, the relays K1, K2, K3 and K6 work, and the normally open contacts are closed to charge the capacitor C; and then K3 and K6 are disconnected, K1, K2, K4 and K5 relays are controlled to work, and the capacitor C charges V3.

It is clear that the specific implementation of the invention is not restricted to the above-described embodiments, but that various insubstantial modifications of the inventive process concept and technical solutions are within the scope of protection of the invention.

Claims (3)

1. The utility model provides an active equalization circuit that retired power battery echelon utilized, includes data acquisition module, main control unit MCU, data acquisition module is arranged in gathering power battery in each free voltage current data of battery respectively, and main control unit MCU, its characterized in that are connected to its output: the circuit further comprises a PWM driving circuit, a bidirectional DCDC balancing module, a capacitance balancing module and a switch array, wherein the output end of the main control unit MCU is connected with the PWM driving circuit, the output end of the PWM driving circuit is connected to the switch array and used for controlling the switch array to be closed and disconnected, the positive electrode and the negative electrode of each battery cell are respectively connected with the two ends of the bidirectional DCDC balancing module and the capacitance balancing module, and the switch array is used for respectively controlling the connection and disconnection between each battery cell and the bidirectional DCDC balancing module and the connection and disconnection between each battery cell and the capacitance balancing module.

2. The active balancing circuit for echelon utilization of decommissioned power cells of claim 1, wherein: the switch array comprises a switch tube array used for controlling the on-off of the battery monomers and the bidirectional DCDC balancing module, the switch tube array is composed of a plurality of switch tubes, two adjacent battery monomers are respectively connected with the bidirectional DCDC balancing module and used for balancing the adjacent battery monomers through the balancing module, each battery monomer corresponds to one switch tube, and the switch tubes are connected between the battery monomers and the bidirectional DCDC balancing module in series.

3. The active balancing circuit for echelon utilization of decommissioned power cells of claim 1, wherein: the switch array further comprises a relay array, the relay array is used for controlling the connection and disconnection between the single battery and the capacitance balancing module, the relay array comprises a plurality of relays, the two ends of the capacitance balancing module are connected to the two ends of each single battery through the relays respectively, and the control end of each relay is connected with the PWM driving circuit.

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