CN103558462B - Detect the apparatus and method of battery management system - Google Patents

Abstract

The present invention provides a device and method for detecting a battery management system. The device includes an adjustable digital power supply, a control unit, a battery unit, and double-pole relays at least equal to the number of battery cells, and the common terminals of each of the double-pole relays are connected in series. , each of the battery units is sequentially connected to the normally closed end of each of the double-pole relays, and the normally-open end of each of the double-pole relays is respectively connected to the adjustable digital power supply; the control unit controls each of the double-pole relays On and off, the control unit also controls the output voltage of the adjustable digital power supply and detects the current of the adjustable digital power supply, wherein the current is used to determine the balance function of the battery management system under test, through The solution of the invention can improve the efficiency of detecting the battery management system, and can traverse all balancing units for balancing management.

Description

Device and method for detecting battery management system

technical field

The invention relates to the technical field of battery pack management, in particular to a device for detecting a battery management system and a method for detecting a battery management system.

Background technique

In high-power applications such as energy storage or electric vehicles, power lithium-ion batteries require multiple single cells to be combined in series and parallel to form an energy storage battery pack to meet the needs of voltage and power. However, due to the influence of the production process and the external environment, the individual cells of the energy storage battery pack are often inconsistent. After multiple charge and discharge cycles, this inconsistency will be reflected in the difference in the capacity of the single battery, which will lead to a reduction in the usable capacity of the energy storage battery. The long-term inconsistent state of the energy storage battery pack will also reduce the service life of the energy storage battery pack. For power storage battery packs with multiple cells connected in series and parallel, one of the most important functions of the battery management system (BMS) is the balanced management of the batteries. Correspondingly, the most important function of the battery management system detection device is to detect whether the balance function of the battery management system is normal or not.

At present, the most commonly used equalization method in the battery management system is to select a single battery with too high voltage, select the corresponding equalization unit to form an equalization circuit, and discharge through a parallel power resistor to reduce the battery voltage. In order to realize the detection of the balance management function mentioned above, the traditional technology is to directly charge and discharge the battery pack, and observe whether the balance function is normal during the charge and discharge process.

The traditional technology has low detection efficiency for the balancing function of the battery management system, and cannot traverse each balancing unit of the battery management system, resulting in low reliability of the detection results.

Contents of the invention

The object of the present invention is to provide a device for detecting a battery management system and a method for detecting a battery management system, which can improve detection efficiency and can traverse each balancing unit of the battery management system.

The purpose of the present invention is achieved through the following technical solutions:

A device for detecting a battery management system, including an adjustable digital power supply, a control unit, a battery unit, and double-pole relays at least equal to the number of battery units, the common ends of each of the double-pole relays are connected in series, and each of the battery units is sequentially connected to the normally closed end of each of the double-pole relays, and the normally open ends of each of the double-pole relays are respectively connected to the adjustable digital power supply;

The control unit controls each of the double-pole relays to be turned on and off, and the control unit also controls the output voltage of the adjustable digital power supply and detects the current of the adjustable digital power supply, wherein the current is used for Determine the balancing function of the battery management system under test.

According to the above-mentioned scheme of the device of the present invention, since the on and off of each of the double-pole relays can be controlled by the control unit, and because the common ends of each double-pole relay are connected in series, the normally open ends of each double-pole relay are respectively connected to Adjustable digital power supply connection, so the common terminal of each double-pole relay can be connected to the adjustable digital power supply through the control unit according to the test requirements, and the balance of the battery management system under test connected to the common terminal of the corresponding double-pole relay is realized. The unit is connected to the adjustable digital power supply connected to the normally open end of the corresponding double-pole relay, and then the control unit controls the output voltage of the adjustable digital power supply and then controls the balance unit added to the corresponding battery management system under test. Voltage, the voltage is adjustable, you can adjust the current of the digital power supply by collecting different voltages, and then determine the equalization function of the corresponding equalization unit according to the current, and then determine the battery under test according to the equalization function of each equalization unit. The balance function of the system, this device can quickly traverse each balance unit of the battery management system, determine the balance function of each balance unit, and then determine the balance function of the battery management system, improve the detection efficiency, and can control the adjustable digital power supply The voltage change simulates various states of the battery unit from normal voltage to overvoltage, and detects the current (balance current) of the adjustable digital power supply in various states, realizing the accurate detection of the balance function of the battery management system.

A battery management system balance detection method, comprising the following steps:

Generate a control signal, control each double-pole relay connected in series with the common end according to the control signal to conduct the common end of one of the double-pole relays with the adjustable digital power supply in turn, wherein the adjustable digital power supply is respectively connected to each The normally open connection of the double-pole relay described above;

Realize the analog battery state switching by controlling the output voltage of the adjustable digital power supply respectively after being turned on, collect the current values of the adjustable digital power supply in different battery states, and determine the current conduction value according to the current values. The balance function of the balance unit connected to the common end of the double-pole relay, and the balance function of the battery management system under test is determined according to the balance function of each balance unit.

According to the scheme of the above-mentioned method of the present invention, since each double-pole relay connected in series with the common end can be controlled, the common end of one said double-pole relay is turned on with the adjustable digital power supply in turn, and after being turned on, by controlling said The output voltage of the adjustable digital power supply realizes the analog battery state switching, collects each current value of the adjustable digital power supply in different battery states, and determines the current value connected to the common terminal of the currently conducting double-pole relay according to each of the current values. The balance function of the balance unit determines the balance function of the battery management system under test according to the balance function of each balance unit. Therefore, each balance unit of the battery management system can be quickly traversed to determine the balance function of each balance unit, and then determine the balance function of the battery management system. The balance function improves the detection efficiency, and can simulate various states of the battery unit from normal voltage to overvoltage through the adjustable digital power supply and the battery unit, and detect the current (balanced current) of the adjustable digital power supply in various states , realizing the accurate detection of the balance function of the battery management system.

Description of drawings

FIG. 1 is a schematic diagram of a working circuit of an equalization unit;

FIG. 2 is a schematic structural diagram of an embodiment of a device for detecting a battery management system of the present invention;

FIG. 3 is a schematic flowchart of an embodiment of a battery management system balance detection method according to the present invention;

FIG. 4 is a detailed flow chart of an embodiment of step S102 in FIG. 2 .

Detailed ways

The present invention will be further described below in conjunction with the embodiments and drawings, but the implementation of the present invention is not limited thereto.

In order to facilitate the understanding of the present invention, the working principle of the balancing unit is first described, as shown in Figure 1, a balancing unit of the battery management system is in the dotted line box, and the single battery (counted as By) connected to the battery management system is as shown in FIG. The voltage V _By at both ends of the single battery By satisfies V _By > (V _th + ΔV), the balancing unit of the battery management system will need to close Kx to turn on the balancing circuit, and the balancing resistance _RB in the balancing circuit is used to balance the single battery. By discharges, thereby causing the voltage of the single battery By to drop, and maintaining the voltage consistency between the single battery By and other single batteries in the series-parallel battery pack. When V _By <(V _th -ΔV) is satisfied, Kx is disconnected , the equalization stops, where V _By is the voltage of the single battery connected to the battery management system, V _th is the equalization opening threshold, and ΔV is the upper limit of the voltage measurement error.

Referring to FIG. 2 , it is a schematic structural diagram of an embodiment of a device for detecting a battery management system according to the present invention. As shown in Figure 2, the device for testing the battery management system in this embodiment includes an adjustable digital power supply, a control unit, a battery unit Bx (x can be 1 to n), and double-pole relays R1 at least equal in number to the number of battery units Bx ~Rn, the common ends of each double-pole relay R1~Rn are connected in series, each battery unit Bx is connected to the normally closed end of each double-pole relay R1~Rn in turn, and one double-pole relay Rx (x can be 1~n) is connected to one battery unit Bx, the normally open ends of each double-pole relay R1-Rn are respectively connected to the adjustable digital power supply;

In this embodiment, the control unit can be realized by a single-chip microcomputer, a special ASIC chip, or a programmable logic device such as DSP, FPGA, CPLD, and EPLD. The number of the battery unit Bx and the double-pole relay Rx is equal to is n, n is a positive integer, and the battery unit Bx corresponds to the single battery managed by the battery management system. The battery unit Bx can be a simulated battery or a physical battery (real battery). For the better, this is considering that frequent testing will shorten the life of the physical battery and increase its internal resistance, which will also affect the accuracy of the test results. Moreover, using a simulated battery will not cause life shortening, internal resistance Increase and other problems, and the voltage can be set at will, which can be more suitable for the test requirements, and the effect is good;

The double-pole relays R1~Rn together form a relay switching matrix, which can connect any number of double-pole relays R1~Rn and disconnect any number of double-pole relays R1~Rn through the control of the control unit;

The common ends of the double-pole relays R1~Rn are the two leads on the right side of each double-pole relay R1~Rn in Figure 2, and the normally closed ends of the double-pole relays R1~Rn are each of the double-pole relays in Figure 2 The first lead-out and the third lead-out (counting from top to bottom) of the four leads on the left side of relays R1~Rn, the normally open ends of double-pole relays R1-Rn are each double-pole relay in Figure 2 The second lead-out end and the fourth lead-out end of the four lead-out ends on the left side of R1～Rn (counting from top to bottom), the connection relationship between the battery unit Bx and the double-pole relay Rx is: the positive pole Bx+ of the battery unit (when When x is 1) connect B1+ of double pole relay R1, negative pole Bx- of battery unit (when x is 1) connect B1- of double pole relay R1, positive pole of battery unit Bx+ (when x is 2) connect double pole Connect B2+ of relay R2, negative pole Bx- of the battery unit (when x is 2) to B2- of double-pole relay R2, and so on;

The control unit can control the double-pole relays R1-Rn to turn on and off, and the control unit can also control the output voltage of the adjustable digital power supply and detect the current of the adjustable digital power supply, wherein the The current is used to determine the equalization function of the battery management system under test;

In specific work, after the device is put into use, the common terminals of each double-pole relay R1~Rn can be respectively connected to a balancing unit of the battery management system under test. For example, BT1 and BT2 correspond to the battery unit B1 connected to the double-pole relay R1. The two connection ends of the equalization unit are equivalent to the situation in which y is taken as 1 in Fig. 1;

Among them, the control unit can control each double-pole relay R1~Rn to turn on and off according to the test needs, which (which) double-pole relays R1~Rn to turn off can be determined according to which equalization units are specifically tested, and one equalizer can be adjusted each time. The unit is tested. The following is an example of testing each equalization unit. Assuming that the number of equalization units is also n, the control unit sequentially connects the adjustable digital power supply to a double-pole relay R1-Rn The common terminal is turned on, that is, the control unit can generate control signals RC1~RCn, and the control signals RC1~RCn act on the double-pole relays R1~Rn respectively (that is, the control signal RC1 acts on the double-pole relay R1... the control signal RCn acts on the double-pole relay Rn) to realize the conduction between the adjustable digital power supply and the common terminal of a double-pole relay R1~Rn. If it is necessary to conduct the adjustable digital power supply and the double-pole relay R1 at present, it will be closed by the control signal RC1 Double-pole relay R1, and disconnect the double-pole relay R2~Rn through the control signal RC2~RCn, so that Bs+ and Bs- are connected to BT1 and BT2 respectively;

After being turned on, the controller can control the adjustable digital power supply connected to it to realize the analog battery state switching. For example, if the adjustable digital power supply and the double-pole relay R1 are currently turned on, the controller can The output voltage simulates the state switching of the battery unit B1, wherein the output voltage can be the normal voltage state corresponding to the battery unit B1 or the overvoltage state, etc., and then the controller can also separately collect the adjustable digital power supply in various voltage states Current value, but not limited to the method of using the controller to collect the current value of the adjustable digital power supply. For example, it can also be collected through other current collection devices, and the operator can determine the connection with the common terminal of the double-pole relay R1 according to each current value The equalization function of the equalization unit;

Determining the balancing function of the balancing unit according to the current value can generally be realized by the following method: judging whether the current value is zero when the voltage of the battery unit Bx is a normal voltage, if so, the balancing function of the corresponding balancing unit is normal, otherwise the balancing function Abnormal, or/and judging whether the current value is the ratio of the voltage of the current battery unit Bx to the equalizing resistance of the corresponding equalizing unit when the voltage of the battery unit Bx is overvoltage, if so, the equalizing function of the corresponding equalizing unit is normal, otherwise Abnormal balance function;

The equalization function of each equalization unit can be determined through the aforementioned method, and when the equalization function of each equalization unit is normal, it is determined that the equalization function of the battery management system under test is normal; otherwise, it indicates that the equalization function of the battery management system under test is abnormal, and the battery management system under test The system needs to be repaired or replaced.

Accordingly, according to the solution of the above-mentioned present embodiment, since the on and off of each double-pole relay R1-Rn can be controlled by the control unit, and since the common terminals of each double-pole relay R1-Rn are connected in series, each double-pole The normally open ends of the relays R1~Rn are respectively connected to the adjustable digital power supply, so the common ends of each double-pole relay R1~Rn can be connected to the adjustable digital power supply according to the test requirements through the control unit, and the connection in the corresponding dual pole relays is realized. The connection between the equalization unit of the battery management system under test at the public end of the pole relays R1~Rn and the battery unit Bx connected to the normally closed end of the corresponding double pole relays R1~Rn, and then the control unit controls the adjustable digital The output voltage of the power supply is output to the common terminal of a double-pole relay, and the voltage is adjustable, so the current of the digital power supply can be adjusted by collecting different voltages, and then the equalization function of the corresponding equalization unit can be determined according to the current , and then determine the balancing function of the battery management system under test according to the balancing function of each balancing unit. This device can quickly traverse each balancing unit of the battery management system to determine the balancing function of each balancing unit, and then determine the balancing function of the battery management system. The detection efficiency is improved, and the various states of the battery cell from normal voltage to overvoltage can be simulated through the adjustable digital power supply and the battery unit, and the current (balanced current) of the adjustable digital power supply in various states can be detected to realize the battery Accurate detection of the balancing function of the management system.

In combination with the above-mentioned device for detecting the battery management system of the present invention, the present invention also provides a method for detecting balance of the battery management system, and the method for detecting balance of the battery management system will be described below.

Referring to FIG. 3 , it is a schematic flowchart of an embodiment of a battery management system balance detection method according to the present invention. As shown in FIG. 3 , the battery management system balance detection method in this embodiment includes the following steps:

Step S101: Generate a control signal, and control each double-pole relay connected in series with the common end according to the control signal to sequentially conduct the common end of one of the double-pole relays with the adjustable digital power supply, wherein the adjustable digital power supply is respectively connected to the normally open ends of each of the double-pole relays;

Turning on the public end of a double-pole relay and the common end of the adjustable digital power supply in turn means that one double-pole relay is turned on each time, while the other remaining double-pole relays are disconnected. If the normally open terminal is connected, the common terminal of a double-pole relay and the adjustable digital power supply can be turned on each time in this way;

Step S102: Realize analog battery state switching by controlling the output voltage of the adjustable digital power supply respectively after being turned on, collect each current value of the adjustable digital power supply in different battery states, and determine the corresponding current value according to each current value The equalization function of the equalization unit connected to the common end of the double-pole relay that is currently turned on determines the equalization function of the battery management system under test according to the equalization function of each equalization unit. The overvoltage and normal voltage corresponding to the battery cell managed by the unit. The battery cell can be the battery in the battery pack managed by the battery management system under test, or it can be a battery that needs to be provided for measurement, as described in the aforementioned device The battery unit, in practical applications, the battery unit is connected to the normally closed end of the double-pole relay.

According to this, according to the scheme of the above-mentioned present embodiment, since each double-pole relay connected in series with the common end can be controlled, the common end of one described double-pole relay and the adjustable digital power supply are turned on in turn, and are respectively passed through the control after the turn-on. The output voltage of the adjustable digital power supply realizes the analog battery state switching, collects each current value of the adjustable digital power supply in different battery states, and determines the common terminal with the currently conducting double-pole relay according to each described current value The balance function of the connected balance unit determines the balance function of the battery management system under test according to the balance function of each balance unit, so it can quickly traverse each balance unit of the battery management system to determine the balance function of the corresponding balance unit, and then determine the balance function of the battery. The balance function of the management system improves the detection efficiency, and can simulate various states of the battery unit from normal voltage to overvoltage through the adjustable digital power supply, and detect the current (balanced current) of the adjustable digital power supply in various states, The accurate detection of the balance function of the battery management system is realized.

In one of the embodiments, the above step S102 may be implemented through the following steps:

Step S1021: By controlling the output voltage of the adjustable digital power supply, adjusting the common terminal voltage of the currently turned on double-pole relay to be greater than the maximum voltage threshold, collecting the second current of the adjustable digital power supply, if the second current is adjustable If the ratio of the output voltage of the digital power supply to the equalizing resistance, the equalizing function of the current equalizing unit is normal, if the second current is not the ratio of the output voltage of the adjustable digital power supply to the equalizing resistance, then the equalizing function of the current equalizing unit abnormal;

The voltage of the battery cell is greater than the maximum voltage threshold, that is, the battery cell is in an overvoltage situation. At this time, it can be known from the above-mentioned working principle of the equalization unit. is the ratio of the voltage of the current battery unit to the balance resistance, if not, the balance function of the current balance unit is abnormal;

Step S1022: By controlling the output voltage of the adjustable digital power supply, adjusting the common terminal voltage of the currently turned on double-pole relay to be less than the minimum voltage threshold, collecting the third current of the adjustable digital power supply, if the third current is zero, Then the equalization function of the current equalization unit is normal, and if the third current is not zero, the equalization function of the current equalization unit is abnormal;

From the above working principle of the equalization unit, it can be known that when the voltage of the battery unit is lower than the minimum voltage threshold, if the equalization function of the equalization unit is normal and the equalization circuit is disconnected, at this time, the third current should be zero, if not zero, at Indicates that the equalization function of the current equalization unit is abnormal;

It should be noted that the above steps S1021 to S1022 can be performed sequentially, but are not limited to the above sequence, and can also be performed at the same time. In addition, the subsequent steps can not be performed when the equalization function of the equalization unit is detected to be abnormal, such as After step S1021 determines that the equalization function of the current equalization unit is abnormal, step 1022 will not be performed. In addition, one of steps S1021 to S1022 may be reduced, for example, only step S1021 or only step S1022 shall be performed;

Step S1023: According to the balancing function of each of the balancing units, it is judged whether the balancing function of the battery management system under test is normal. If the balancing functions of each of the balancing units are normal, then the balancing function of the battery management system under test is normal;

Perform the above steps S1021 to S1022 in a loop until each balancing unit of the battery management system has passed the judgment of whether the balancing function is normal or not, then judge whether the balancing function of the battery management system under test is normal according to the balancing function of each of the balancing units, If the balancing function of each of the balancing units is normal, then the balancing function of the battery management system under test is normal.

In one embodiment, after step S102, a step may be further included: determining whether the battery management system under test needs to be replaced or repaired according to the balancing function of each balancing unit or the balancing function of the battery management system under test.

In one of the embodiments, after step S102, a step may further be included: according to the equalization function of each equalization unit, the equalization unit that needs to be replaced or repaired is determined.

The above-mentioned embodiments only express several implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but should not be construed as limiting the patent scope of the present invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims (8)

1. A device for detecting a battery management system, characterized in that it includes an adjustable digital power supply, a control unit, a battery unit, and double-pole relays at least equal to the number of battery cells, and the common ends of each of the double-pole relays are connected in series, Each of the battery units is sequentially connected to the normally closed end of each of the double-pole relays, and the normally-open end of each of the double-pole relays is respectively connected to the adjustable digital power supply; The control unit controls each of the double-pole relays to be turned on and off, and the control unit also controls the output voltage of the adjustable digital power supply and detects the current of the adjustable digital power supply, wherein the current is used for Determine the balancing function of the battery management system under test. 2. The device for detecting a battery management system according to claim 1, wherein the battery unit is a simulated battery or a real battery. 3 . The device for detecting a battery management system according to claim 1 , wherein the output voltage includes an overvoltage and a normal voltage corresponding to the battery unit. 4 . 4. A method for detecting a battery management system, comprising the steps of: Generate a control signal, control each double-pole relay connected in series with the common end according to the control signal to conduct the common end of one of the double-pole relays with the adjustable digital power supply in turn, wherein the adjustable digital power supply is respectively connected to each The normally open connection of the double-pole relay described above; Realize the analog battery state switching by controlling the output voltage of the adjustable digital power supply respectively after being turned on, collect the current values of the adjustable digital power supply in different battery states, and determine the current conduction value according to the current values. The balance function of the balance unit connected to the common end of the double-pole relay, and the balance function of the battery management system under test is determined according to the balance function of each balance unit. 5. The method for detecting a battery management system according to claim 4, wherein the battery status includes overvoltage and normal voltage. 6. The method for detecting a battery management system according to claim 4, wherein the simulated battery state switching is realized by controlling the output voltage of the adjustable digital power supply after the conduction respectively, and when collecting different battery states For each current value of the adjustable digital power supply, determine the equalization function of the equalization unit connected to the common end of the currently conducting double-pole relay according to each of the current values, and determine the balance function of the battery management system under test according to the equalization function of each equalization unit. The steps of the equalization function include the following steps: By controlling the output voltage of the adjustable digital power supply, adjusting the common terminal voltage of the currently turned on double-pole relay to be greater than the maximum voltage threshold, collecting the second current of the adjustable digital power supply, if the second current is the adjustable digital power supply The ratio of the output voltage to the equalizing resistance means that the equalizing function of the current equalizing unit is normal; if the second current is not the ratio of the output voltage of the adjustable digital power supply to the equalizing resistance, then the equalizing function of the current equalizing unit is abnormal; By controlling the output voltage of the adjustable digital power supply, the voltage at the common terminal of the double-pole relay that is currently turned on is adjusted to be less than the minimum voltage threshold, and the third current of the adjustable digital power supply is collected. If the third current is zero, the current current The balancing function of the balancing unit is normal, if the third current is not zero, the balancing function of the current balancing unit is abnormal; According to the balancing function of each of the balancing units, it is judged whether the balancing function of the battery management system under test is normal. If the balancing functions of each of the balancing units are normal, then the balancing function of the battery management system under test is normal. 7. The method for detecting a battery management system according to claim 4, further comprising the steps of: Whether the battery management system under test needs to be replaced or repaired is determined according to the balance function of each balance unit or the balance function of the battery management system under test. 8. The method for detecting a battery management system according to claim 4, further comprising the steps of: The balancing unit that needs to be replaced or repaired is determined according to the balancing function of each balancing unit and the balancing function of the battery management system under test.