Be implemented in the charging process battery balanced device and methodTechnical field
The present invention relates to a kind of being implemented in the charging process to battery balanced device and method.
Background technology
Battery is used so that higher output voltage and bigger power capacity to be provided by connection in series-parallel usually, satisfies the demand of load driving.Because rechargeable battery has cost performance preferably, is widely used in each electronic product, even in the motor vehicle.Yet, no matter be lithium rechargeable batteries, plumbic acid rechargeable battery, or nickel-hydrogen chargeable cell, because all there is certain difference in the restriction of process conditions between the monomer electricity core, though can come part to deal with problems by the method for combo, but through after the charge and discharge cycle repeatedly, still can produce bigger voltage difference between the battery, the total available capacity of series battery is reduced, influence battery pack serviceability and life-span.Particularly when battery was used to motor vehicle, it is particularly outstanding that this influence becomes.
Be directed to this, people's battery balanced method and apparatus that begins one's study by adjusting the voltage of a certain battery in the series battery respectively, makes each cell voltage be close, thereby can make each battery reach higher charged state substantially simultaneously.More common method is to adopt the Single-chip Controlling method at present, promptly obtain the voltage of every batteries respectively by the Single-chip Controlling sample circuit, it is compared, according to circumstances drive the discharge circuit on the respective battery again, make the higher battery discharge of voltage, thereby reach the equilibrium between each batteries.This method is owing to need accurately measure each batteries voltage, and total voltage of series battery is higher, cause the difficulty in the measurement, adding needs the corresponding single chip machine controlling circuit of configuration, make entire circuit realize that cost is higher, only be used at present the requirement of battery pressure reduction is wanted in the high lithium rechargeable batteries group, this also is to cause lithium rechargeable batteries to form one of this higher reason.
Summary of the invention
The purpose of this invention is to provide a kind of being implemented in the charging process, all batteries can both be full of by the present invention to battery balanced device and method.
The objective of the invention is to be achieved through the following technical solutions:
A kind of being implemented in the charging process to battery balanced device, comprise battery management system (BMS), management system (BMS) connects power supply and charging master switch (KZC) respectively, power supply connects charging anodal (CHG+), charging master switch (KZC) connects charging negative pole (CHG-), battery management system (BMS) go up to connect some equalizer switches (Km), and equalizer switch (Km) is connected with discharge resistance (Rm), discharge resistance (Rm) rechargeable battery pack (Em) that is connected in parallel.BMS is by reading the voltage in the battery pack, just can send during greater than the threshold values set when the difference of maximum voltage in the battery pack and minimum voltage needs balanced order, by control power supply and charging master switch (KZC), open the equalizer switch of the corresponding battery of maximum voltage and shunt; When maximum voltage during greater than the protection magnitude of voltage of battery BMS give an order and turn-off KZC.Described charging master switch (KZC) is made up of relay, mos field effect transistor (MOSFET) and insulated gate bipolar transistor (IGBT).
A kind of being implemented in the charging process battery balanced method may further comprise the steps:
(1) at first reads the voltage parameter of each battery of battery pack in real time by BMS;
(2) send the order that needs equilibrium during greater than the threshold values of the equalizing voltage of setting during greater than the threshold values set or when maximum voltage when the difference of maximum voltage in the battery pack and minimum voltage;
(3) BMS is implemented in the current charge that falls under the prerequisite of not adjusting charger current according to the ratio of opening of given charging current reduction KZC;
(4) when current charge falls in step (3), judge the relation of the minimum value of the maximum protection voltage of maximum voltage and setting or charging current effective value and setting by BMS, close KZC greater than the maximum protection voltage of setting or charging current effective value during less than the minimum value set when maximum voltage, charging finishes; Otherwise jump to step (1).
Beneficial effect of the present invention is: extensibility is good, only needs the string number increase and decrease units corresponding according to battery, and adopting device is the switching controls device, specific (special) requirements such as no high-power, high pressure, and cost is low.
Description of drawings
With reference to the accompanying drawings the present invention is described in further detail below.
Fig. 1 is the described circuit theory diagrams that are implemented in the charging process battery balanced device of the embodiment of the invention.
Embodiment
As shown in Figure 1, described a kind of being implemented in the charging process of the embodiment of the invention to battery balanced device, comprise battery management system (BMS), battery management system (BMS) connectspower supply 1 and charging master switch (KZC) respectively, power supply connects charging anodal (CHG+), charging master switch (KZC) connects charging negative pole (CHG-), battery management system (BMS) is gone up and is connected some equalizer switches (Km), equalizer switch (Km) is connected with discharge resistance (Rm), discharge resistance (Rm) rechargeable battery pack (Em) that is connected in parallel.Described charging master switch (KZC) is made up of relay, mos field effect transistor (MOSFET) and insulated gate bipolar transistor (IGBT).
A kind of being implemented in the charging process battery balanced method may further comprise the steps:
(1) at first reads the voltage parameter of each battery of battery pack in real time by BMS;
(2) send the order that needs equilibrium during greater than the threshold values of the equalizing voltage of setting during greater than the threshold values set or when maximum voltage when the difference of maximum voltage in the battery pack and minimum voltage;
(3) BMS is implemented in the current charge that falls under the prerequisite of not adjusting charger current according to the ratio of opening of given charging current reduction KZC;
(4) when current charge falls in step (3), judge the relation of the minimum value of the maximum protection voltage of maximum voltage and setting or charging current effective value and setting by BMS, close KZC greater than the maximum protection voltage of setting or charging current effective value during less than the minimum value set when maximum voltage, charging finishes; Otherwise jump to step (1).
By reducing the duty ratio of KZC, realize that all batteries can both be full of.In charging process, can read that all cell voltages are basic functions of BMS in the battery pack, just can send during greater than the threshold values set when the difference of maximum voltage in this battery pack and minimum voltage needs balanced order, open the wherein equalizer switch of the corresponding battery of maximum voltage, realize shunting charging current.When maximum voltage during greater than the protection magnitude of voltage of battery BMS give an order and turn-off KZC, charging process finishes.Briefly, can be described as Q=∫ E(t to the ability of equalization)/RLiDt is because euqalizing current E(t)/RLiMuch smaller than charging current, till being full of, this battery only accounts for below 10% of whole charging process institute time-consuming from finding that certain battery is unbalanced to the end during this period of time as BMS simultaneously, so above-mentioned ability of equalization Q is very limited than the total capacity of battery pack.
The present invention can go to control opening than (PWM) of KZC by the method for conventional software programming, after above-mentioned equilibrium reaches coda, reduces the ratio of opening of KZC, and at this moment the effective value of charging current can be expressed as IEff=K(PWM) * IFillWork as IEff=E(t)/RLi+ IQThe time, at that battery of equilibrium, the effective value of charging current is zero for, and can also not carry out effective value those batteries of doing equilibrium be (I with concerning not being full of promptlyEff-IQ) charging.That is to say in this charging process the battery that is full of electricity is not recharged, those batteries that are not full of electricity are replenished electricity, be full of one of an equilibrium, all be full of up to all batteries, KZC closes fully.Can calculate, whole additional power consumption is QMend=(IEff-IQ) h.
The present invention does not increase the assembling difficulty, and extensibility is good, only needs the string number increase and decrease units corresponding according to battery; Adopting device is the switching controls device, specific (special) requirements such as no high-power, high pressure, and cost is low, benefit simple in structure; Can realize that all batteries can both be full of.