CN112087018A

CN112087018A - Charger and charging method thereof

Info

Publication number: CN112087018A
Application number: CN202010766954.9A
Authority: CN
Inventors: 杨新新; 程志明; 余杰; 周刚; 陈�胜; 谢爽; 叶剑
Original assignee: Chaowei Power Group Co Ltd
Current assignee: Chaowei Power Group Co Ltd
Priority date: 2019-12-09
Filing date: 2020-08-03
Publication date: 2020-12-15
Also published as: CN112087019A; CN112087025A; CN212462861U

Abstract

The invention relates to a charging method, which comprises the following steps: step 1: quick charging; step 2: slowly charging; and step 3: and (3) floating charging, wherein the floating charging current in the step (3) is between 0.005 and 0.05C or the floating charging unit cell voltage is between 2.33 and 2.67V. The charging method can ensure the balance consistency of the rechargeable battery.

Description

Charger and charging method thereof

Technical Field

The invention relates to the field of storage batteries.

Background

In the returned batteries on the market at present, the failure caused by single falling behind is one of the main reasons of the early failure of the storage battery. In the manufacturing process of the storage battery, microscopic deviations exist in the aspects of raw materials, parts, manufacturing processes and the like of a single battery; in the using process, the single batteries are connected in series to form a group of batteries for use, and the voltage consistency of the storage battery pack in the charging and discharging process is different due to the influence of factors such as open-circuit voltage, electric charge, self-discharge, capacity and decline rate thereof, internal resistance and change rate thereof along with time and the like. The more the unit cells that participate in the combination, the greater the probability that a difference will occur. With the use of the batteries, namely the continuous cycle life, the difference is gradually increased, and the phenomenon that the discharge termination pressure difference between the single batteries is larger and larger, so that the overcharge and the overdischarge of a certain battery and the shallow charge and the shallow discharge of other batteries occur until the storage battery pack is discarded due to the capacity attenuation and the service life termination.

At present, a commonly used three-stage charging method adopts a floating charge constant voltage or constant current mode, for example, to avoid other factors such as gas evolution and water loss at the stage, a set constant voltage value is generally low, and individual differences of each battery are inherent, even if the constant voltage mode is adopted in the step 3, although the sum of the voltages of all batteries reaches the constant voltage, the saturation of each battery is still the same, and the floating charge voltage is different. Meanwhile, with the promotion of new national standards, the requirement on the energy density of the storage battery is increased, the saturation of the storage battery after the charging stage of the step 2 is lower than that of the storage battery in the past, the requirement on the charging amount of the step 3 is stronger, and the step 3 using the current market charging system cannot be reached, so that the difference between the batteries is larger and larger in the step 3, and the consistency is poorer and poorer.

Disclosure of Invention

In order to solve the above technical problem, the present invention provides a charging method, including the following steps: step 1: quick charging; step 2: slowly charging; and step 3: and (3) floating charging, wherein the floating charging current in the step (3) is between 0.005 and 0.05C or the floating charging unit cell voltage is between 2.33 and 2.67V.

Further, the floating charge time in the step 3 is between 0.5 and 3 hours.

Further, the floating charge time value in the step 3 is inversely proportional to the charge current value.

Further, the step 2 slow charging comprises slow constant voltage time-limited charging.

Further, the step 1 rapid charging includes constant current or constant voltage charging until the cell reaches a specific voltage.

The charging method can ensure the balance consistency of the rechargeable battery.

Drawings

Fig. 1 is a block circuit diagram of the charger of the present invention.

Detailed Description

The invention is further described with reference to specific examples.

The invention provides a charger of a lead-acid storage battery 6, which comprises a switch circuit 1, a charging circuit 2, a voltage detection circuit 3, a lamp turning circuit such as a second timing circuit 4, a current detection circuit 7, a controller 5 and a first timing circuit 8. The switching circuit 1 is used for completing alternating current-direct current conversion of commercial power, providing working power supplies of other circuit modules in the charger and providing charging current or charging voltage; the charging circuit 2 is used for receiving a charging current or charging voltage signal provided by the switch circuit 1 and providing the charging current or charging voltage signal to the storage battery 6; the voltage and current detection circuit 3 realizes battery voltage detection and sends a detection result to the controller 5; when the result detected by the voltage and current detection circuit 3 meets the condition, the controller 5 controls the charging circuit 2 to enter the corresponding charging mode, and also can simultaneously activate the second timing circuit 4 to control the charging circuit 2 to enter the time-limited charging mode. When the lamp turning circuit meets the condition of battery lamp turning, a lamp turning signal is sent to the controller 5; the controller 5 activates the first timing circuit 8 according to the light turning signal and controls the charging circuit 2 to enter the corresponding charging mode. The lamp turning signal of the lamp turning circuit may be the lamp turning timing signal of the second timing circuit 4, may be the lamp turning current signal of the current detection circuit 7, or may be the lamp turning timing signal or the lamp turning current signal that the second timing circuit 4 and the current detection circuit 7 first satisfy the lamp turning condition.

When the battery starts to charge, the commercial power is converted into a controllable charging voltage or charging current signal through AC-DC (alternating current-direct current), the controller controls the charging circuit to enter a first phase, namely a rapid charging phase, for example, constant current charging with a larger current I1, the current I1 is preferably between 0.15C and 2.0C, and also can be constant voltage or constant power rapid charging. The controller turns on the voltage detection circuit to detect the battery voltage, if the detected voltage value reaches the battery cell voltage and preferably reaches 2.3V-2.4V, the controller controls the switch circuit and the charging circuit to enter the second stage to charge with a small current such as 0.1C, when the voltage reaches the constant voltage of the stage, the timing circuit can be activated and the charging circuit can be controlled to charge with a constant voltage, the charged constant cell voltage is preferably between 2.33V-2.67V, when the lamp-turning current of the current detection circuit 7 reaches or the preset lamp-turning time of the second timing circuit 4 reaches, the controller controls the charging circuit to enter the third stage, namely the floating charging stage, and simultaneously activates the first timing circuit 8, preferably to charge with a constant current between 0.005C-0.05C or to charge with a constant voltage of the cell voltage between 2.33V-2.67V for a period of time, the charging time set by the first timer circuit 8 is preferably between 0.5 and 3 hours until the entire charging process is completed.

The charging method of the lead-acid storage battery comprises the following steps: step 1, in the initial quick charging stage, such as heavy current constant current charging, the charging current is 0.15-2.0C, and the voltage is limited to 2.3-2.40V/cell. The charge state of the battery at this stage is low, the charge acceptance is strong, the charging voltage basically does not generate gas, the charging is generally completed at the negative electrode to about 90 percent of the charge state, the charging time can be shortened by setting the charging with larger current, and the activation and recovery effects on the capacity of the storage battery are realized, and the experiment proves that the storage battery begins to generate gas when the voltage is charged to 2.3V/cell; when the voltage is charged to 2.3V-2.50V, the gassing rate starts to increase significantly. And 2, in the intermediate slow charging stage, if constant-voltage time-limited charging is carried out, the negative electrode charging is basically finished through the step 1, and the intermediate slow charging stage mainly plays a role of completely charging the positive electrode. At the moment, the battery has poor charging acceptance, and a large amount of gas can be generated by setting too large current or too high voltage, so that the water loss is increased, and the thermal runaway phenomenon of the battery is easy to occur. The parameter settings are therefore as follows: the voltage is limited to 2.40V/cell-2.55V/cell, the voltage can be charged with a small current such as 0.1C, when the voltage reaches the constant voltage at the stage, timing is started, the time is limited for 1-3h, when the set time is up, the lamp is turned to the step 3, the thermal runaway risk caused by the temperature rise of the battery can be avoided through time limitation, the service life of the battery is also ensured, and in the step, the lamp can be turned by setting the current, namely when the current is lower than 0.015C-0.03C, the lamp is turned to the step 3, or the current lamp turning and the time-limited lamp are simultaneously set. And step 3: and a later floating charge stage, such as a small current reinforcing stage. The basic process charge stage of the cell at this point is primarily responsible for balancing/reinforcing the individual cells and the individual cells. The later floating charging stage is charged in a limited time mode, the thermal runaway risk is guaranteed to be controlled, and the balance consistency and the service life of the rechargeable battery are guaranteed through reasonable setting of charging current or charging voltage. Parameters are as follows: the charging current is 0.005-0.05C, and the charging time is 0.5-3.0 h. Or the constant voltage charging with the unit cell voltage between 2.33V and 2.67V is adopted. Therefore, the chemical metering coefficient of the lead oxide of the corrosion layer can be improved, the battery can achieve the effect of equalizing charge, wherein C is the capacity of the battery in two hours, and excessive water loss is avoided through time control.

Eight groups of batteries (four in each group are connected in series, and each battery is 12V) with 6-DZF-20 models and similar capacity and pressure difference are selected to carry out a normal-temperature cycle life experiment. And verifying the influence of the later floating charge stage on thermal runaway, service life and consistency of the battery. And (5) carrying out data processing on the average number of the tail removed verification results.

Example 1

Step 1: constant current is 0.125C, charging is carried out until the voltage is 2.46V/cell, and the step 2 is skipped;

step 2: constant voltage is 2.46V/cell, current is limited to 0.125C, charging is carried out until the current is reduced to 0.025C, and the step 3 is skipped;

and step 3: constant current 0.005C, charging 0.5 hours/1 hour/2 hours/3 hours/4 hours, and charging is finished.

Example 2

and step 3: constant current 0.015C, charging 0.5 hour/1 hour/2 hour/3 hour/4 hours, and end of charging.

Example 3

and step 3: constant current 0.02C, charging 0.5 hours/1 hour/2 hours/3 hours/4 hours, and finishing charging.

Example 4

and step 3: constant current 0.025C, charging 0.5 hours/1 hour/2 hours/3 hours/4 hours, and end of charging.

Example 5

and step 3: constant current 0.03C, charging 0.5 hours/1 hour/2 hours/3 hours/4 hours, and finishing charging.

Example 6

and step 3: constant current 0.035C, charging 0.5 hours/1 hour/2 hours/3 hours/4 hours, and charging is finished.

Example 7

and step 3: constant current 0.04C, charging 0.5 hours/1 hour/2 hours/3 hours/4 hours, and finishing charging.

Example 8

and step 3: constant current 0.05C, charging 0.5 hours/1 hour/2 hours/3 hours/4 hours, and finishing charging.

TABLE 1 thermal runaway test results

TABLE 2 cycle life verification results

TABLE 3 verification of differential pressure between battery packs

The following conclusions are drawn through the test verification: as shown in table 1, in step 3, as the charging time increases, the risk of thermal runaway increases, and as the charging current increases, the risk of thermal runaway also increases in step 3, and in order to better avoid thermal runaway, it is preferable that the charging current value is inversely proportional to the charging time value; as shown in table 2, in step 3, as the charging time increases, the battery life increases, but as the charging time exceeds 3 hours, the life decreases, and as the current increases, this is more pronounced; as shown in table 3, in step 3, as the charging current is larger, the uniformity of the battery is better, and the charging current value is proportional to the charging time value, which is beneficial to uniformity. Therefore, the battery equalization is not guaranteed, and a large current is needed for charging; in addition, thermal runaway and battery life are avoided, the charging time is preferably less than 3 hours, and in order to ensure consistency, the charging time is preferably more than 0.5 hour, and matched current can be further adjusted according to the set specific time which does not cause thermal runaway, so that better battery balance and service life are achieved. Certainly, in the step 3, charging can also be performed by presetting proper voltage, for example, constant voltage charging of single grid voltage between 2.33V and 2.67V is performed, and then six groups of batteries (four in each group, 12V each) with 6-DZF-20 models and similar capacities and pressure differences are selected for performing normal-temperature cycle life experiments. And verifying the influence of the later floating charge stage on thermal runaway, service life and consistency of the battery. And (5) carrying out data processing on the average number of the tail removed verification results.

Examples 9 to 14

Example 9

and step 3: the charging was completed at a current of 1A, a constant voltage of 2.25V/cell, and a charging time of 0.5 hr/1 hr/2 hr/3 hr/4 hr.

Example 10

and step 3: the charging was completed at a current of 1A, a constant voltage of 2.33V/cell, and a charging time of 0.5 hr/1 hr/2 hr/3 hr/4 hr.

Example 11

and step 3: the charging was completed at a current of 1A, a constant voltage of 2.42V/cell, and a charging time of 0.5 hr/1 hr/2 hr/3 hr/4 hr.

Example 12

and step 3: the charging was completed at a current of 1A, a constant voltage of 2.50V/cell, and a charging time of 0.5 hr/1 hr/2 hr/3 hr/4 hr.

Example 13

and step 3: the charging was completed at a current of 1A, a constant voltage of 2.58V/cell, and a charging time of 0.5 hr/1 hr/2 hr/3 hr/4 hr.

Example 14

and step 3: the charging was completed at a current of 1A, a constant voltage of 2.67V/cell, and a charging time of 0.5 hr/1 hr/2 hr/3 hr/4 hr.

TABLE 4 thermal runaway test results

TABLE 5 cycle life verification results

TABLE 6 verification of differential pressure between battery packs

The following conclusions are drawn through the test verification: as shown in table 4, in step 3, as the charging time increases, the risk of thermal runaway increases, and at the same time, as the charging voltage increases, the risk of thermal runaway also increases in step 3, and in order to better avoid thermal runaway, it is preferable that the charging voltage value is inversely proportional to the charging time value; as shown in table 5, in step 3, as the charging time increases, the battery life increases, but as the charging time exceeds 3 hours, the life decreases, and as the voltage increases, this is more pronounced; as shown in table 6, in step 3, the charging voltage of 2.25V does not substantially reach the equalization effect, and as the charging voltage is higher, the consistency of the battery is better, and the charging voltage value is proportional to the charging time value, which is beneficial to the consistency. Therefore, the battery equalization is not guaranteed, and a larger voltage is needed for charging; in addition, thermal runaway and battery service life are avoided, the charging time is preferably less than 3 hours, in order to ensure consistency, the charging time is preferably more than 0.5 hour, the voltage value is set between 2.33V and 2.67V of a unit cell, and the specific time which does not cause thermal runaway can be set according to needs, so that better effects of battery balance, service life and consistency are achieved.

The above-described embodiments are only preferred embodiments of the present invention, and are not intended to limit the present invention in any way, and other variations and modifications may be made without departing from the spirit of the invention as set forth in the claims.

Claims

1. A method of charging a battery comprising the steps of: step 1: quick charging; step 2: slowly charging; and step 3: and (3) floating charging, wherein the floating charging current in the step (3) is between 0.005 and 0.05C or the floating charging unit cell voltage is between 2.33 and 2.67V.

2. The charging method according to claim 1, wherein the float charging time in the step 3 is between 0.5 and 3 hours.

3. The charging method according to claim 2, wherein the floating charge charging time value in the step 3 is inversely proportional to the charging current value.

4. A charging method according to any one of claims 1 to 3, wherein said step 2 slow charging comprises slow constant voltage time limited charging.

5. The charging method according to claim 4, wherein the step 1 rapid charging includes constant-current or constant-voltage charging until the cell reaches a certain voltage.