CN107589378A - Storage battery equalization device and method - Google Patents

Abstract

The invention provides a storage battery equalization device and method, the device includes: a test line, a test device, and a main control machine; the test device is electrically connected to the positive and negative poles of the battery through the test line to form a circuit, and also communicates with the main control machine connection, used to control the battery to output the excitation current signal of preset frequency, receive the excitation current signal and sample the response voltage signal of the battery, and calculate the resistance of the battery’s ohmic resistance R1 and polarization resistance R2 through the response voltage signal and excitation current signal value, and transmit the resistance values of ohmic resistance R1 and polarization resistance R2 to the main control machine; the main control machine is used to compare the resistance values of ohmic resistance R1 and polarization resistance R2 with the preset resistance value, when Or when the polarization resistance R2 is greater than the preset resistance value, it is judged that the battery is abnormal, and the battery is controlled to be activated. The invention can reasonably judge whether the accumulator is balanced, and can activate the unbalanced accumulator.

Description

Battery balancing device and method

technical field

The invention relates to the field of electric power technology, in particular to a storage battery balancing device and method.

Background technique

Batteries have a very wide and important application in the fields of electric power, communication, transportation and so on. Power system substation operating power supply, communication power supply, computer room UPS (Uninterruptible Power System/Uninterruptible Power Supply, uninterruptible power supply), as well as energy storage power stations, photovoltaic power stations, and electric vehicles, all use batteries as backup power systems, energy storage batteries or power supplies in large quantities. . Especially in the backup power supply system or the DC power supply system of the mobile base station, a large number of batteries in groups are used, and each battery has 50 to hundreds of batteries. In the past, the battery application field considered more about the safety of the battery, including battery failure detection, battery aging detection, battery temperature detection, battery loss of water, early warning of battery status and other safety indicators. However, a large number of batteries are used. For the users, in addition to the safety factor, the cost factor is also highlighted, that is, the battery efficiency and economic benefits have become another key issue to solve.

At present, the service life of a single battery cell is generally 8 to 10 years, but in actual use, due to the use of batteries in groups, the general service life can only reach about 5 years. After 5 years, these batteries will be replaced. If all of them are replaced, the problem caused by this is that the service life of the battery pack is greatly shortened, and the purchase cost increases. In addition, in the battery pack, not all single cells have reached the end of their life. If these batteries are stopped and replaced, the use efficiency will be reduced, which will cause great waste, and cause negative impacts in terms of saving, energy saving and environmental protection.

In addition to the traditional consideration of the safety of battery use, it is urgent to solve the problems of battery use efficiency and economic benefits caused by large-scale use of batteries (groups). Through a professional battery monitoring management and maintenance system, unqualified batteries are eliminated, batteries with consistent screening parameters are regrouped and balanced for reuse, prolonging battery life, reducing unnecessary waste of batteries, saving cost, energy saving, environmental protection, and economic benefits. is of great significance.

Currently, battery equalization management is mainly aimed at voltage equalization. By detecting the voltage of each single battery in the battery pack, discharge the battery with too high voltage, or charge the battery with low voltage to achieve the purpose of balancing the voltage of each battery. However, the battery is a complex electrochemical energy conversion system, the most important is its state of charge SOC (State of Charge, state of charge) and state of health SOH (Section Of Health, battery health state), even if the voltage is the same, its capacity The states are not necessarily the same, therefore, the existing battery balancing judgment method is unreasonable.

Contents of the invention

In order to solve the above technical problems, the present invention provides a storage battery equalization device and method, which can reasonably judge whether the storage battery is balanced, and can activate the unbalanced storage battery.

A storage battery equalization device provided by the present invention includes: a test line, a test device, and a main control machine;

The test device is electrically connected to the positive and negative poles of the storage battery through the test line to form a loop, and is also connected to the main control machine in communication, for controlling the storage battery to output an excitation current signal with a preset frequency, and receiving The excitation current signal and the response voltage signal of the storage battery are sampled, and the resistance values of the ohmic resistance R1 and the polarization resistance R2 of the storage battery are calculated through the response voltage signal and the excitation current signal, and the ohmic The resistance values of the resistance R1 and the polarization resistance R2 are sent to the main control computer;

The main control machine is used to compare the resistance values of the ohmic resistance R1 and the polarization resistance R2 with a preset resistance value, when the ohmic resistance R1 or the polarization resistance R2 is greater than the preset resistance value , it is judged that the battery is abnormal, and the battery is controlled to be activated.

Preferably, the test line includes a 4pin plug electrically connected to the test device, and a current test line and a voltage test line respectively electrically connected to the 4pin plug, the current test line and the voltage test line The wire is electrically connected with the positive and negative poles.

Preferably, the testing device includes:

The PMW control circuit is electrically connected to the positive and negative poles through the test line to form the loop, and is used to control the battery to output the excitation current signal by changing the on-off of the loop, wherein the The excitation current signal is a square wave signal;

A data processing module, electrically connected to the test line, for receiving the excitation current signal and sampling the response voltage signal, and calculating the ohmic resistance R1 and the response voltage signal according to the excitation current signal and the response voltage signal The resistance value of the polarization resistance R2 is determined, and the resistance values of the ohmic resistance R1 and the polarization resistance R2 are sent to the main control computer.

Preferably, the ohmic resistor R1 includes a positive and negative column resistor R14, a busbar resistor R13, a grid resistor R12, and a grid connection resistor R11;

The polarization resistor R2 includes a paste resistor R21, an electrolyte resistor R22, and an isolator resistor R23.

Preferably, the current test line is a signal line with a carrier communication function, and the main controller is connected to the test device through the current test line;

The testing device is used to transmit the resistance values of the ohmic resistance R1 and the polarization resistance R2 to the main control computer in the form of carrier signals.

Preferably, the current test line includes a first current test line and a second current test line, and the voltage test line includes a first voltage test line and a second voltage test line;

When the positive and negative poles of the storage battery are longer than the preset length, the current test lines are respectively connected to the upper ends of the positive and negative pole bases and the voltage test lines are respectively connected to the lower ends of the positive and negative pole bases , or, the current test lines are respectively connected to the lower ends of the positive and negative pole bases and the voltage test lines are respectively connected to the upper ends of the positive and negative pole bases;

Wherein, the connection points between the current test line and the voltage test line and the positive and negative poles are located inside the positive and negative poles at the same time, or are located outside the positive and negative poles at the same time.

Preferably, when the positive and negative poles are shorter than the preset length, the current test lines are respectively connected to the upper ends of the positive and negative pole bases and the voltage test lines are respectively connected to the positive and negative pole bases or, the current test line is respectively connected to the lower ends of the positive and negative pole bases and the voltage test line is respectively connected to the lower ends of the positive and negative pole bases;

Wherein, the connection points between the current test line and the positive and negative poles are respectively located outside the positive and negative poles, and the connection points between the voltage test line and the positive and negative poles are respectively located on the positive and negative poles or, the connection points between the current test line and the positive and negative poles are respectively located inside the positive and negative poles, and the connection points between the voltage test line and the positive and negative poles are respectively located at the inner side of the positive and negative poles. The outer side of the above-mentioned positive and negative poles;

And, pass the connection point between the current test line and the positive and negative poles as the first perpendicular line to the axis of the positive and negative poles, and pass through the connection point between the voltage test line and the positive and negative poles The connection point is used as a second perpendicular to the axis of the positive and negative poles, and the angle between the first perpendicular and the second perpendicular is in the range of 60° to 180°.

Preferably, when the positive and negative poles are shorter than the preset length, the current test lines are respectively connected to the upper ends of the positive and negative pole bases and the voltage test lines are respectively connected to the lower ends of the positive and negative pole bases Connecting, or, the current test line is respectively connected to the lower ends of the positive and negative pole bases and the voltage test line is respectively connected to the lower ends of the positive and negative pole bases;

Wherein, the connection point between the current test line and the positive and negative poles is located inside the positive and negative poles, and the connection point between the voltage test line and the positive and negative poles is located on the positive and negative poles. The outer side of the negative pole, or the connection point between the current test line and the positive and negative poles is located outside the positive and negative poles and the connection point between the voltage test line and the positive and negative poles The connection point is located inside the positive and negative poles.

Preferably, the preset length ranges from 5 mm to 15 mm.

The present invention also provides a battery equalization method, comprising the following steps:

Electrically connect one end of the test line to the positive and negative poles of the battery, and the other end to the test device;

controlling the storage battery to output two sets of excitation current signals with different frequencies through the testing device;

The test device receives the excitation current signal, and samples the response voltage signal of the storage battery;

The test device calculates the resistance values of the ohmic resistance R1 and the polarization resistance R2 of the storage battery through the response voltage signal and the excitation current signal, and sends the resistance values of the ohmic resistance R1 and polarization resistance R2 to to the host computer;

The main controller compares the ohmic resistance R1 and the polarization resistance R2 with a preset resistance value, and when the resistance value of the ohmic resistance R1 or the polarization resistance R2 is greater than the preset resistance value , controlling the storage battery to perform activation treatment.

Preferably, the test line includes a 4pin plug electrically connected to the test device, and a current test line and a voltage test line respectively electrically connected to the 4pin plug, the current test line and the voltage test line The wire is electrically connected to the positive and negative poles;

The current test line includes a first current test line and a second current test line, and the voltage test line includes a first voltage test line and a second voltage test line;

When the positive and negative poles of the storage battery are longer than the preset length, the current test lines are respectively connected to the upper ends of the positive and negative pole bases and the voltage test lines are respectively connected to the lower ends of the positive and negative pole bases , or, the current test lines are respectively connected to the lower ends of the positive and negative pole bases and the voltage test lines are respectively connected to the upper ends of the positive and negative pole bases;

Wherein, the connection points between the current test line and the voltage test line and the positive and negative poles are located inside the positive and negative poles at the same time, or are located outside the positive and negative poles at the same time.

Preferably, when the positive and negative poles are shorter than the preset length, the current test lines are respectively connected to the upper ends of the positive and negative pole bases and the voltage test lines are respectively connected to the positive and negative pole bases or, the current test line is respectively connected to the lower ends of the positive and negative pole bases and the voltage test line is respectively connected to the lower ends of the positive and negative pole bases;

Wherein, the connection points between the current test line and the positive and negative poles are respectively located outside the positive and negative poles, and the connection points between the voltage test line and the positive and negative poles are respectively located on the positive and negative poles or, the connection points between the current test line and the positive and negative poles are respectively located inside the positive and negative poles, and the connection points between the voltage test line and the positive and negative poles are respectively located at the inner side of the positive and negative poles. The outer side of the above-mentioned positive and negative poles;

And, pass the connection point between the current test line and the positive and negative poles as the first perpendicular line to the axis of the positive and negative poles, and pass through the connection point between the voltage test line and the positive and negative poles The connection point is used as a second perpendicular to the axis of the positive and negative poles, and the angle between the first perpendicular and the second perpendicular is in the range of 60° to 180°.

Preferably, when the positive and negative poles are shorter than the preset length, the current test lines are respectively connected to the upper ends of the positive and negative pole bases and the voltage test lines are respectively connected to the lower ends of the positive and negative pole bases Connecting, or, the current test line is respectively connected to the lower ends of the positive and negative pole bases and the voltage test line is respectively connected to the lower ends of the positive and negative pole bases;

Wherein, the connection point between the current test line and the positive and negative poles is located inside the positive and negative poles, and the connection point between the voltage test line and the positive and negative poles is located on the positive and negative poles. The outer side of the negative pole, or the connection point between the current test line and the positive and negative poles is located outside the positive and negative poles and the connection point between the voltage test line and the positive and negative poles The connection point is located inside the positive and negative poles.

Implementing the present invention has the following beneficial effects: the equivalent circuit inside the accumulator includes ohmic resistance R1 and polarization resistance R2, the root cause of the imbalance of the accumulator is the difference in the appearance of internal electrochemical substances, and the ohmic resistance R1 and polarization resistance R2 can be Characterize the state of the electrochemical substances inside the battery; control the battery to output excitation current signals of different frequencies through the test device, calculate the resistance values of the ohmic resistance R1 and the polarization resistance R2 according to the excitation current signal and the response voltage signal, and calculate the resistance values of the ohmic resistance R1 and the resistance value of the polarization resistance R2 are sent to the main control computer, and the main control computer compares the resistance values of the ohmic resistance R1 and the polarization resistance R2 with the preset resistance value, when the ohmic resistance R1 or the polarization resistance R2 is greater than the preset resistance value, it is judged that the battery is abnormal, and the battery is controlled to be activated.

By activating and maintaining the battery, it is possible to compensate for the unbalanced difference between the SOC of the battery and the SOH of the state of health, and achieve a consistent state for the entire set of batteries, thus avoiding the dehydration of some batteries due to long-term overcharging, and also avoiding Due to long-term undercharging of some batteries, sulfation occurs, which significantly improves the safety and reliability of operation, prolongs the service life of batteries, saves costs, and has huge economic benefits.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is a functional block diagram of a storage battery balancing device provided by the present invention.

Fig. 2 is a Thevenin equivalent circuit diagram inside the storage battery provided by the present invention.

Fig. 3 is a schematic diagram of the test line provided by the present invention.

Fig. 4 is a functional block diagram of the testing device provided by the present invention.

Fig. 5 is an internal electrochemical equivalent circuit diagram of the storage battery provided by the present invention.

Figures 6a, 6b, and 6c are schematic diagrams of the wiring of the positive and negative poles on three different storage batteries provided by the present invention.

Fig. 7 is a schematic diagram of an equivalent circuit of a battery four-terminal connection method in another embodiment provided by the present invention.

detailed description

The present invention provides a storage battery balancing device. As shown in FIG.

The test device 1 is electrically connected to the positive and negative poles of the storage battery 3 through a test line to form a loop, and is also connected to the main control machine 2 by communication.

As shown in FIG. 2 , the equivalent circuit inside the storage battery 3 includes an ohmic resistance R1 and a polarization resistance R2 .

The test device 1 is used to control the battery 3 to output an excitation current signal with a preset frequency, receive the excitation current signal and sample the response voltage signal of the battery 3, and calculate the ohmic resistance R1 and polarization of the battery 3 through the response voltage signal and the excitation current signal. The resistance value of the resistor R2, and the resistance values of the ohmic resistor R1 and the polarization resistor R2 are sent to the main control computer 2.

The main control machine 2 is used to compare the resistance value of the ohmic resistance R1 and the polarization resistance R2 with the preset resistance value, and when the resistance value of the ohmic resistance R1 or the polarization resistance R2 is greater than the preset resistance value, it is judged that the battery 3 is abnormal, and The storage battery 3 is controlled to perform activation treatment until the storage battery 3 reaches a balanced state. Specifically, if the storage battery 3 is abnormal, that is, the storage battery 3 is unbalanced, the activation process is performed by controlling the charging and discharging of the storage battery 3 .

The root cause of the imbalance of battery 3 is the difference in internal electrochemical substances, mainly due to long-term overcharging and undercharging, which lead to sulfation, water loss, and the decrease in the concentration of effective active substances in the electrolyte, resulting in voltage and actual charge SOC (Stateof Charge, state of charge), state of health SOH (Section Of Health, battery 3 state of health) and other imbalances. Therefore, it is a feasible and effective method to use the R1 and R2 parameters that characterize the state of the active material inside the battery 3 as a method for judging the balance of the battery 3 according to the composition structure of the internal resistance of the battery 3 .

Further, as shown in FIG. 3 , the test line includes a 4pin plug electrically connected to the test device 1, and a current test line, a voltage test line, a current test line, and a voltage test line respectively electrically connected to the 4pin plug. The wire is electrically connected to the positive and negative poles. Specifically, the current test line includes a first current test line B+ and a second current test line B−, and the voltage test line includes a first voltage test line V+ and a second voltage test line V−.

Further, as shown in FIG. 4 , the test device 1 includes: a PMW control circuit 11 and a data processing module 12 .

The PMW (Pulse Width Modulation, pulse width modulation) control circuit 11 is electrically connected to the positive and negative poles through the test line to form a loop, and is used to control the battery 3 to output the excitation current signal by changing the on-off of the loop, wherein the excitation current signal is square wave signal.

The data processing module 12 is electrically connected with the test line, and is used to receive the excitation current signal and the sampling response voltage signal, calculate the resistance values of the ohmic resistance R1 and the polarization resistance R2 according to the excitation current signal and the response voltage signal, and convert the ohmic resistance R1 and the resistance value of the polarization resistor R2 are sent to the main control computer 2. Wherein, the excitation current signal and the response voltage signal are both square wave signals, which can be transformed by Fourier transform.

According to the standard that the frequency of the AC excitation current signal has the greatest correlation with the capacity of the VRLA battery (valve-regulated lead-acid battery, sealed valve-regulated lead-acid battery), two currents with low frequency (generally f, 2*f) and amplitude are used The signals are successively applied to the electrode terminals of the unit cells, and the corresponding response voltage signal output of the storage battery 3 is detected, and the corresponding circuit parameter values are calculated according to Ohm's law.

Let the frequency of the first AC excitation current signal be f,

in, is the phase angle corresponding to the initial moment of the excitation current signal;

The response voltage signal is:

in, is the phase angle corresponding to the initial moment of the response voltage signal;

The phase angle difference between the response voltage signal and the excitation current signal is

in,

AC Impedance:

The real part of Z ₁ is:

Imaginary part of Z ₁ :

Let the frequency of the second AC excitation current signal be 2f,

The response voltage signal is:

The phase angle difference of voltage signal and current signal is

The AC impedance is:

The real part of Z ₂ is:

_The imaginary part of Z2 is:

On the other hand, according to the Thevenin (Thevenin) circuit model of the VRLA storage battery, the total impedance of the circuit is obtained according to the circuit:

Obviously, when the first frequency is excited, Z=Z ₁ ; when the second frequency is excited, Z=Z ₂ .

According to the equality of complex numbers, the corresponding real and imaginary parts must be equal to get the system of equations:

; where, ω ₁ =0.5ω ₂ =2πft.

To solve this system of equations, shill δ=ω ₁ R ₂ C ₂ ,

but

or

Further, as shown in Figure 5, the ohmic resistor R1 includes positive and negative column resistors R14, bus bar resistors R13, grid plate resistors R12, grid plate connection resistors R11, positive and negative column resistors R14, bus bar resistors R13, grid plate resistors Plate resistance R12 and grid connection resistance R11 are metal resistances with ohmic characteristics; polarization resistance R2 includes paste resistance R21, electrolyte resistance R22, isolator resistance R23, paste resistance R21, electrolyte resistance R22, and isolator resistance R23 are both resistors with polarization properties, which do not follow ohmic properties.

Furthermore, the current test line is a signal line with a carrier communication function, and the main control machine 2 is connected to the test device 1 through the current test line. Specifically, one end of the current test line is connected to the positive and negative poles, and the main control machine 2 can also be connected to the corresponding positive and negative poles at the same time, so as to realize the connection with the current test line.

The testing device 1 is used to transmit the resistance values of the ohmic resistance R1 and the polarization resistance R2 to the main control computer 2 in the form of carrier signals.

Further, the current test line includes a first current test line B+ and a second current test line B-, and the voltage test line includes a first voltage test line V+ and a second voltage test line V-.

When the positive and negative poles of the storage battery 3 are greater than the preset length, the current test lines are respectively connected to the upper ends of the positive and negative pole bases and the voltage test lines are respectively connected to the lower ends of the positive and negative pole bases, or the current test lines are respectively connected to the positive and negative pole bases. The lower end of the base of the negative pole is connected and the voltage test line is respectively connected with the upper ends of the base of the positive and negative poles.

Wherein, the connection points between the current test line and the voltage test line and the positive and negative poles are located inside the positive and negative poles at the same time, or are located outside the positive and negative poles at the same time. It should be noted that the inner side of the positive and negative poles is the opposite surface of the positive pole and the negative pole, the outer side of the positive pole is the side facing away from the inner side of the positive pole, and the outer side of the negative pole is the side facing away from the inner side of the negative pole. one side.

Specifically, for example, as shown in Figure 6a, the first current test line B+ is connected to the inner side of the upper end of the base of the positive pole, the second current test line B- is connected to the inner side of the upper end of the base of the negative pole, and the first voltage test line V+ is connected to the inner side of the upper end of the base of the negative pole. The inner side of the lower end of the base of the positive pole is connected, and the second voltage test line V- is connected to the inner side of the lower end of the base of the negative pole. Alternatively, the first current test line B+ is connected to the outer side of the upper end of the positive pole base, the second current test line B- is connected to the upper outer side of the negative pole base, the first voltage test line V+ is connected to the lower end of the positive pole base, and the second The voltage test line V- is connected to the outside of the lower end of the base of the negative pole.

Further, when the positive and negative poles are less than the preset length, the current test lines are respectively connected to the upper ends of the positive and negative pole bases and the voltage test lines are respectively connected to the upper ends of the positive and negative pole bases, or the current test lines are respectively connected to the positive and negative pole bases. The lower end of the base of the negative pole is connected and the voltage test line is respectively connected with the lower ends of the base of the positive and negative poles.

Wherein, the connection points of the current test line and the positive and negative poles are located on the outside of the positive and negative poles respectively, and the connection points of the voltage test line and the positive and negative poles are respectively located on the inside of the positive and negative poles, or the current test line and the positive and negative The connection points of the poles are respectively located inside the positive and negative poles, and the connection points between the voltage test line and the positive and negative poles are respectively located outside the positive and negative poles.

And, pass the connection point between the current test line and the positive and negative poles as the first perpendicular to the axis of the positive and negative poles, and pass the connection point between the voltage test line and the positive and negative poles as the first perpendicular to the axis of the positive and negative poles Two perpendicular lines, the angle between the first perpendicular line and the second perpendicular line ranges from 60° to 180°.

Specifically, for example, as shown in Figure 6b, the first current test line B+ and the first voltage test line V+ are respectively connected to the outer and inner sides of the upper end of the positive pole base, and the second current test line B- and the second voltage test line V- is respectively connected to the outer side and inner side of the upper end of the base of the negative pole. Alternatively, the first current test line B+ and the first voltage test line V+ are respectively connected to the inner side and outer side of the upper end of the positive pole base, and the second current test line B- and second voltage test line V- are respectively connected to the inner side of the upper end of the negative pole base. connected to the outside.

Alternatively, the first current test line B+ and the first voltage test line V+ are respectively connected to the outer side and the inner side of the lower end of the positive pole base, and the second current test line B- and the second voltage test line V- are respectively connected to the outer side of the lower end of the negative pole base. connected to the inside. Alternatively, the first current test line B+ and the first voltage test line V+ are respectively connected to the inside and outside of the lower end of the positive pole base, and the second current test line B- and the second voltage test line V- are respectively connected to the inner side of the lower end of the negative pole base. connected to the outside.

Further, when the positive and negative poles are less than the preset length, the current test lines are respectively connected to the upper ends of the positive and negative pole bases and the voltage test lines are respectively connected to the lower ends of the positive and negative pole bases, or the current test lines are respectively connected to the positive and negative pole bases. The lower end of the base of the negative pole is connected and the voltage test line is respectively connected with the lower ends of the base of the positive and negative poles.

Wherein, the connection point between the current test line and the positive and negative poles is located inside the positive and negative poles and the connection point between the voltage test line and the positive and negative poles is located outside the positive and negative poles, or the current test line and The connection point between the positive and negative poles is located on the outside of the positive and negative poles and the connection point between the voltage test line and the positive and negative poles is located on the inside of the positive and negative poles.

Specifically, for example, as shown in Figure 6c, the first voltage test line V+ is connected to the inner side of the upper end of the base of the positive pole, the second voltage test line V- is connected to the inner side of the upper end of the base of the negative pole, and the first current test line B+ is connected to the inner side of the upper end of the base of the negative pole. The outer side of the lower end of the base of the positive pole is connected, and the second current test line B- is connected to the outer side of the lower end of the base of the negative pole. Alternatively, the first voltage test line V+ is connected to the outer side of the upper end of the positive pole base, the second voltage test line V- is connected to the outer side of the upper end of the negative pole base, the first current test line B+ is connected to the inner side of the lower end of the positive pole base, and the second Current test line B-connect with the inner side of the lower end of the base of the negative pole.

The connection methods between the current test line and the voltage test line and the positive and negative poles listed above can be collectively referred to as the four-terminal connection method. In view of the fact that the internal resistance of a normal battery 3 is very small, the internal resistance of different brands of batteries 3 is different when they leave the factory, but generally between a few milliohms and several milliohms. It cannot be ignored. Therefore, when the test line is connected to the positive and negative terminals of the battery 3, the above-mentioned four-terminal connection method is adopted to avoid mutual interference between the current test line and the voltage test line.

Further, the range of the preset length is 5-15 mm, preferably, the preset length is 10 mm.

In another embodiment provided by the present invention, since the internal resistance of the storage battery 3 is at the level of a few tenths to several milliohms, in order to reduce the influence of the connection resistance and the line resistance on the internal resistance test of the storage battery 3, four methods of the internal resistance test of the storage battery 3 are used. The terminal wiring method, the internal resistance test of the battery 3 passes a pair of voltage test lines of the test device 1, and a pair of current test lines are connected to the positive and negative poles of the battery 3, and the voltage and current test lines on the positive and negative poles are separated by a certain distance. The terminal wiring method uses the excitation current signal of a certain frequency applied to the battery 3 by the test device 1, samples the response voltage signal of the battery 3, and calculates the internal resistance of the battery 3 through a preset mathematical algorithm; the balance of the battery 3 is based on the Thevenin of the battery 3 The circuit model measures the ohmic resistance R1 and polarization resistance R2 parameters of the battery 3. In the battery 3 group, the battery 3 whose R1 and R2 parameters are too large are selected for activation, so that the electrochemical substances inside the battery 3 can be recovered to the maximum extent. State, within the allowable range, the parameter values of R1 and R2 of each battery are consistent, and after grouping, the battery state is balanced.

The four-terminal wiring method of the battery 3 internal resistance test, one end of the test line for testing the internal resistance of the battery 3 is a 4pin plug, the hole distance of the 4pin plug is 2.54mm, and the other end of the test line is a pair of current test lines and a pair of voltage test lines , two pairs of test lines are connected to the positive and negative poles of the battery 3; a pair of current test lines are divided into positive current test line B+, negative current test line B-; a pair of voltage test lines are divided into positive voltage test line V+, negative voltage test line Line V-. A pair of voltage test lines V+ and V- are also the power lines for the test device 1 to get power from the battery 3; a pair of current lines B+ and B- are also the signal lines for the carrier communication of the test device 1. During the internal resistance test, the carrier channel function Closed, after the internal resistance test is completed, the carrier channel function is turned on, and the test device 1 sends a carrier signal to the outside through the current test line.

The four-terminal wiring method for the internal resistance test of the battery 3, according to the structure of the poles of the positive and negative electrodes of the battery 3, the wiring is divided into three situations, including the upper and lower wiring method, the horizontal wiring method and the diagonal wiring method; the height of the pole base is greater than Up and down wiring can be used if it is above 10mm, and horizontal wiring or diagonal wiring can be used if the height of the pole base is less than 10mm.

The four-terminal wiring method for the internal resistance test of the battery 3, the upper and lower wiring is suitable for the case where the height of the base of the battery 3 poles is not less than 10mm, the current test lines B+ and B- are respectively connected to the upper edge of the base of the positive pole and the negative pole of the battery 3, and the connection point It is located on the opposite side of the two poles; the voltage test lines V+ and V- are respectively connected under the base of the positive pole and the negative pole, and the connection point is located directly below the connection point of the current test line. The distance between the connection points of the test lines is at least 10mm, which can be appropriately relaxed according to the actual structure size of the positive and negative poles, and the wiring of the positive and negative electrodes conforms to the principle of symmetry.

The four-terminal wiring method for the internal resistance test of the battery 3, the horizontal wiring is suitable for the case where the height of the base of the battery 3 poles is less than 10mm, the current test lines B+ and B- are respectively connected to the upper edge of the base of the positive pole and the negative pole of the battery 3, and the connection points are located at The outer side of the pole on the line connecting the axis points of the two poles; the voltage test lines V+ and V- are respectively connected to the edge of the base of the positive pole and the negative pole, and the connection point is located on the inside of the pole on the line connecting the axis points of the two poles; the same The upper edge of the pole base, the angle between the connection point of the voltage test line and the connection point of the current test line can also be between 60° and 180°, corresponding to the pole with opposite polarity, connect the corresponding voltage according to the symmetrical principle of the two poles Test leads or current test leads.

The diagonal connection method in the four-terminal wiring method specifically refers to: the current test line is connected to the upper edge of the positive pole base, and the voltage test line is connected to the bottom of the positive pole base diagonally across the axis line from the connection point of the current test line. ; On the negative pole, connect the current test line and the voltage test line according to the principle of symmetry with the positive pole.

According to the principle of the Thevenin circuit model of the battery, the ohmic resistance R1 is a metal resistance with ohmic characteristics, which includes pole resistance, bus resistance, grid resistance, and grid connection resistance. Since the three batteries of the battery are overcharged or undercharged, The sulfation of battery 3 is caused, and relatively dense salinized particles are formed on the metal surface of the positive and negative electrodes, which increases the ohmic resistance R1; the polarization resistance R2 is an electrochemical resistance with polarization characteristics, which includes paste resistance, electrolyte resistance and The isolator resistance, due to the phenomenon of overcharging or undercharging of the 3 batteries of the battery, will cause water loss, sulfation, electrolyte and active material concentration reduction, which will increase the polarization resistance R2, so R1 and R2 are used as Batteries 3 capacity reduction, unbalanced basis.

Using the test device 1 of the multi-frequency point AC internal resistance test method, the battery 3 is controlled by the test device 1 to output a variety of excitation current signals of different frequencies, and the values of R1 and R2 are measured. Compared with the reference standard value, the internal resistance parameter is abnormal The batteries are screened out and activated. After activation, the state of the storage battery 3 reaches the specified parameter value, so that the storage battery 3 of the entire battery pack reaches a balanced state again.

As shown in Figure 7, the number 1 is the equivalent circuit structure of the battery, the number 2 is the positive pole of the battery, the number 3 is the negative pole of the battery, the number 4 is the equivalent resistance r1 of the positive current test line, and the number 5 is the resistance r2 of the negative current test line ; The number 6 is the resistance r3 of the positive voltage test line, the number 7 is the resistance r4 of the negative voltage test line, and the number 8 is the internal resistance test device. The test current I all flows through the battery under test 3, so the voltage drop of r3 and r4 is 0V, and the voltage drop Uo at both ends of the measured voltage U and the battery under test 3 is basically the same, so it is not affected by r1, r2, r3 and r4 , the R1 and R2 values obtained by measuring the internal resistance of the storage battery 3 in this way are more accurate.

After accurately obtaining the R1 and R2 parameters of each battery 3 in the battery 3 group, according to the statistical comparison, the batteries whose parameter values do not conform to the routine are subjected to online activation treatment, and finally the goal of balance is achieved. The specific method is, under the control of the intelligent control device, if R1 is too large in the fully charged state, which means that the SOH is insufficient, the battery 3 is automatically charged and discharged with a current of 0.1C for one cycle, and the charging cut-off voltage is 1.2 times the nominal value. Voltage, such as 2V battery activation charging cut-off voltage is 2.4V, discharge cut-off voltage is 0.9 times the nominal voltage, such as 2V battery activation discharge cut-off voltage is 1.8V; when the polarization resistance R2 is too high in the fully charged state, it will automatically adjust the battery 3 Discharge to the cut-off voltage; automatically charge the storage battery 3 to the cut-off voltage when the SOC is insufficient. After multiple activations, until the R1 and R2 parameters reach or approach the normal value, if there is still no improvement, then pick out this part of the battery, and the battery that is still within the usable range, and regroup the battery with the same parameter value, if If it reaches the aging and discarding standard, it will be replaced, scrapped and recycled. According to the R1, R2 parameter values and the cut-off voltage control of charge and discharge, the automatic maintenance of the battery 3 is realized, the unbalanced self-discharge of the battery is compensated, and the dehydration of some batteries due to the long-term overcharge state is avoided, and some batteries are under-charged for a long time. The phenomenon of sulfation due to charging state can significantly improve the safety and reliability of operation and prolong the service life of the battery.

The present invention also provides a battery balancing method, which includes the following steps:

Electrically connect one end of the test line to the positive and negative poles of the battery 3, and electrically connect the other end to the test device 1;

The battery 3 is controlled by the test device 1 to output two sets of excitation current signals with different frequencies;

The test device 1 receives the excitation current signal, and samples the response voltage signal of the storage battery 3;

The test device 1 calculates the resistance values of the ohmic resistance R1 and the polarization resistance R2 of the storage battery 3 by responding to the voltage signal and the excitation current signal, and transmits the resistance values of the ohmic resistance R1 and the polarization resistance R2 to the main controller 2;

The main control computer 2 compares the ohmic resistance R1 and the polarization resistance R2 with the preset resistance value, and when the resistance value of the ohmic resistance R1 or the polarization resistance R2 is greater than the preset resistance value, controls the battery 3 to perform activation processing until the battery 3 reach a state of equilibrium. Specifically, the activation process is performed by controlling charge and discharge of the storage battery 3 .

Further, the test line includes a 4pin plug electrically connected to the test device 1, and a current test line and a voltage test line respectively electrically connected to the 4pin plug, and the current test line and the voltage test line are electrically connected to the positive and negative poles ;

When the positive and negative poles of the storage battery 3 are greater than the preset length, the current test lines are respectively connected to the upper ends of the positive and negative pole bases and the voltage test lines are respectively connected to the lower ends of the positive and negative pole bases, or the current test lines are respectively connected to the positive and negative pole bases. The lower end of the base of the negative pole is connected and the voltage test line is respectively connected with the upper end of the base of the positive and negative poles;

Wherein, the connection points between the current test line and the voltage test line and the positive and negative poles are located inside the positive and negative poles at the same time, or are located outside the positive and negative poles at the same time.

Further, when the positive and negative poles are less than the preset length, the current test lines are respectively connected to the upper ends of the positive and negative pole bases and the voltage test lines are respectively connected to the upper ends of the positive and negative pole bases, or the current test lines are respectively connected to the positive and negative pole bases. The lower end of the base of the negative pole is connected and the voltage test line is respectively connected with the lower ends of the base of the positive and negative poles;

Wherein, the connection points of the current test line and the positive and negative poles are located on the outside of the positive and negative poles respectively, and the connection points of the voltage test line and the positive and negative poles are respectively located on the inside of the positive and negative poles, or the current test line and the positive and negative The connection points of the poles are respectively located on the inside of the positive and negative poles, and the connection points of the voltage test line and the positive and negative poles are respectively located on the outside of the positive and negative poles;

And, pass the connection point between the current test line and the positive and negative poles as the first perpendicular to the axis of the positive and negative poles, and pass the connection point between the voltage test line and the positive and negative poles as the first perpendicular to the axis of the positive and negative poles Two perpendicular lines, the angle between the first perpendicular line and the second perpendicular line ranges from 60° to 180°.

Further, when the positive and negative poles are less than the preset length, the current test lines are respectively connected to the upper ends of the positive and negative pole bases and the voltage test lines are respectively connected to the lower ends of the positive and negative pole bases, or the current test lines are respectively connected to the positive and negative pole bases. The lower end of the base of the negative pole is connected and the voltage test line is respectively connected with the lower ends of the base of the positive and negative poles.

Wherein, the connection point between the current test line and the positive and negative poles is located inside the positive and negative poles and the connection point between the voltage test line and the positive and negative poles is located outside the positive and negative poles, or the current test line and The connection point between the positive and negative poles is located on the outside of the positive and negative poles and the connection point between the voltage test line and the positive and negative poles is located on the inside of the positive and negative poles.

To sum up, battery 3 is a complex electrochemical energy conversion system. The most important thing is its state of charge SOC and state of health SOH. Even if the voltage is the same, its capacity state may not be the same. Therefore, more model parameters of battery 3 are needed To judge and measure the internal state. According to Thevenin battery model theory, it is a more reasonable judgment method to use the ohmic internal resistance R1 and polarization internal resistance R2 representing the internal electrochemical structure of the battery as the basis for the balance judgment. Select the batteries with abnormal R1 and R2 from a large number of batteries for activation treatment. By activating and maintaining the battery 3, the difference in the battery charge SOC and the unbalanced state of health SOH can be compensated to achieve a consistent state of the entire battery pack, thereby avoiding It can prevent some batteries from dehydration due to long-term overcharging, and can also avoid the phenomenon of sulfation of some batteries due to long-term undercharging, which significantly improves the safety and reliability of operation and prolongs the service life of batteries 3 , saving costs and having huge economic benefits.

The above content is a further detailed description of the present invention in conjunction with specific preferred embodiments, and it cannot be assumed that the specific implementation of the present invention is limited to these descriptions. For those of ordinary skill in the technical field of the present invention, without departing from the concept of the present invention, some simple deduction or replacement can be made, which should be regarded as belonging to the protection scope of the present invention.

Claims (13)

1. A storage battery balancing device, characterized in that it includes: a test line, a test device, and a main control machine; The test device is electrically connected to the positive and negative poles of the storage battery through the test line to form a loop, and is also connected to the main control machine in communication, for controlling the storage battery to output an excitation current signal with a preset frequency, and receiving The excitation current signal and the response voltage signal of the storage battery are sampled, and the resistance values of the ohmic resistance R1 and the polarization resistance R2 of the storage battery are calculated through the response voltage signal and the excitation current signal, and the ohmic The resistance values of the resistance R1 and the polarization resistance R2 are sent to the main control computer; The main control machine is used to compare the resistance values of the ohmic resistance R1 and the polarization resistance R2 with a preset resistance value, when the ohmic resistance R1 or the polarization resistance R2 is greater than the preset resistance value , it is judged that the battery is abnormal, and the battery is controlled to be activated. 2. The storage battery balancing device according to claim 1, wherein the test line includes a 4pin plug electrically connected to the test device, and a current test line and a current test line electrically connected to the 4pin plug respectively. The voltage test line, the current test line and the voltage test line are electrically connected to the positive and negative poles. 3. The storage battery balancing device according to claim 1, wherein the testing device comprises: The PMW control circuit is electrically connected to the positive and negative poles through the test line to form the loop, and is used to control the battery to output the excitation current signal by changing the on-off of the loop, wherein the The excitation current signal is a square wave signal; A data processing module, electrically connected to the test line, for receiving the excitation current signal and sampling the response voltage signal, and calculating the ohmic resistance R1 and the response voltage signal according to the excitation current signal and the response voltage signal The resistance value of the polarization resistance R2 is determined, and the resistance values of the ohmic resistance R1 and the polarization resistance R2 are sent to the main control computer. 4. The battery balancing device according to claim 1, wherein the ohmic resistor R1 includes a positive and negative column resistor R14, a busbar resistor R13, a grid resistor R12, and a grid connection resistor R11; The polarization resistor R2 includes a paste resistor R21, an electrolyte resistor R22, and an isolator resistor R23. 5. The battery balancing device according to claim 2, wherein the current test line is a signal line with a carrier communication function, and the main controller is connected to the test device through the current test line; The testing device is used to transmit the resistance values of the ohmic resistance R1 and the polarization resistance R2 to the main control computer in the form of carrier signals. 6. The storage battery balancing device according to claim 2, wherein the current test line includes a first current test line and a second current test line, and the voltage test line includes a first voltage test line and a second test line Two voltage test lines; When the positive and negative poles of the storage battery are longer than the preset length, the current test lines are respectively connected to the upper ends of the positive and negative pole bases and the voltage test lines are respectively connected to the lower ends of the positive and negative pole bases , or, the current test lines are respectively connected to the lower ends of the positive and negative pole bases and the voltage test lines are respectively connected to the upper ends of the positive and negative pole bases; Wherein, the connection points between the current test line and the voltage test line and the positive and negative poles are located inside the positive and negative poles at the same time, or are located outside the positive and negative poles at the same time. 7. The battery balancing device according to claim 6, wherein when the positive and negative poles are shorter than the preset length, the current test wires are respectively connected to the upper ends of the bases of the positive and negative poles and The voltage test lines are respectively connected to the upper ends of the positive and negative pole bases, or the current test lines are respectively connected to the lower ends of the positive and negative pole bases and the voltage test lines are respectively connected to the positive and negative poles The lower end connection of the column base; Wherein, the connection points between the current test line and the positive and negative poles are respectively located outside the positive and negative poles, and the connection points between the voltage test line and the positive and negative poles are respectively located on the positive and negative poles or, the connection points between the current test line and the positive and negative poles are respectively located inside the positive and negative poles, and the connection points between the voltage test line and the positive and negative poles are respectively located at the inner side of the positive and negative poles. The outer side of the above-mentioned positive and negative poles; And, pass the connection point between the current test line and the positive and negative poles as the first perpendicular line to the axis of the positive and negative poles, and pass through the connection point between the voltage test line and the positive and negative poles The connection point is used as a second perpendicular to the axis of the positive and negative poles, and the angle between the first perpendicular and the second perpendicular is in the range of 60° to 180°. 8. The storage battery balancing device according to claim 6, wherein when the positive and negative poles are shorter than the preset length, the current test wires are respectively connected to the upper ends of the bases of the positive and negative poles and the The voltage test lines are respectively connected to the lower ends of the positive and negative pole bases, or the current test lines are respectively connected to the lower ends of the positive and negative pole bases and the voltage test lines are respectively connected to the positive and negative pole bases The lower end connection; Wherein, the connection point between the current test line and the positive and negative poles is located inside the positive and negative poles, and the connection point between the voltage test line and the positive and negative poles is located on the positive and negative poles. The outer side of the negative pole, or the connection point between the current test line and the positive and negative poles is located outside the positive and negative poles and the connection point between the voltage test line and the positive and negative poles The connection point is located inside the positive and negative poles. 9 . The battery balancing device according to claim 6 , wherein the preset length ranges from 5 mm to 15 mm. 10. A storage battery balancing method, characterized in that it comprises the following steps: Electrically connect one end of the test line to the positive and negative poles of the battery, and the other end to the test device; controlling the storage battery to output two sets of excitation current signals with different frequencies through the testing device; The test device receives the excitation current signal, and samples the response voltage signal of the storage battery; The test device calculates the resistance values of the ohmic resistance R1 and the polarization resistance R2 of the storage battery through the response voltage signal and the excitation current signal, and sends the resistance values of the ohmic resistance R1 and polarization resistance R2 to to the host computer; The main controller compares the ohmic resistance R1 and the polarization resistance R2 with a preset resistance value, and when the resistance value of the ohmic resistance R1 or the polarization resistance R2 is greater than the preset resistance value , controlling the storage battery to perform activation treatment. 11. The storage battery equalization method according to claim 10, characterized in that: The test line includes a 4pin plug electrically connected to the test device, and a current test line and a voltage test line respectively electrically connected to the 4pin plug, the current test line and the voltage test line are connected to the The positive and negative poles are electrically connected; The current test line includes a first current test line and a second current test line, and the voltage test line includes a first voltage test line and a second voltage test line; When the positive and negative poles of the storage battery are longer than the preset length, the current test lines are respectively connected to the upper ends of the positive and negative pole bases and the voltage test lines are respectively connected to the lower ends of the positive and negative pole bases , or, the current test lines are respectively connected to the lower ends of the positive and negative pole bases and the voltage test lines are respectively connected to the upper ends of the positive and negative pole bases; Wherein, the connection points between the current test line and the voltage test line and the positive and negative poles are located inside the positive and negative poles at the same time, or are located outside the positive and negative poles at the same time. 12. The battery balancing device according to claim 11, wherein when the positive and negative poles are shorter than the preset length, the current test wires are respectively connected to the upper ends of the bases of the positive and negative poles and The voltage test lines are respectively connected to the upper ends of the positive and negative pole bases, or the current test lines are respectively connected to the lower ends of the positive and negative pole bases and the voltage test lines are respectively connected to the positive and negative poles The lower end connection of the column base; Wherein, the connection points between the current test line and the positive and negative poles are respectively located outside the positive and negative poles, and the connection points between the voltage test line and the positive and negative poles are respectively located on the positive and negative poles or, the connection points between the current test line and the positive and negative poles are respectively located inside the positive and negative poles, and the connection points between the voltage test line and the positive and negative poles are respectively located at the inner side of the positive and negative poles. The outer side of the above-mentioned positive and negative poles; And, pass the connection point between the current test line and the positive and negative poles as the first perpendicular line to the axis of the positive and negative poles, and pass through the connection point between the voltage test line and the positive and negative poles The connection point is used as a second perpendicular to the axis of the positive and negative poles, and the angle between the first perpendicular and the second perpendicular is in the range of 60° to 180°. 13. The battery balancing device according to claim 11, characterized in that, when the positive and negative poles are shorter than a preset length, the current test wires are respectively connected to the upper ends of the bases of the positive and negative poles and the The voltage test lines are respectively connected to the lower ends of the positive and negative pole bases, or the current test lines are respectively connected to the lower ends of the positive and negative pole bases and the voltage test lines are respectively connected to the positive and negative pole bases The lower end connection; Wherein, the connection point between the current test line and the positive and negative poles is located inside the positive and negative poles, and the connection point between the voltage test line and the positive and negative poles is located on the positive and negative poles. The outer side of the negative pole, or the connection point between the current test line and the positive and negative poles is located outside the positive and negative poles and the connection point between the voltage test line and the positive and negative poles The connection point is located inside the positive and negative poles.