CN106740228A - Voltage consistency detection method and device and voltage equalization method and device - Google Patents

Abstract

Embodiments of the present invention provide a voltage consistency detection method and device, and a voltage equalization method and device. On the one hand, the embodiment of the present invention detects the voltage difference and energy difference between the first battery system and the second battery system; based on the voltage difference and the energy difference, it is judged that the first battery system and the Whether the voltage consistency between the second battery systems is met, wherein, when the voltage consistency is met, the first battery system and the second battery system are connected in parallel, and the factors of different internal resistance values of different battery systems are considered , through the voltage difference and energy difference between the battery systems to comprehensively judge whether the battery systems meet the voltage consistency, improve the accuracy of the voltage consistency detection, and solve the problem of accurate detection of the branch voltage consistency of the multi-branch parallel battery system relatively low-level problem.

Description

Voltage consistency detection method and device, voltage equalization method and device

【Technical field】

The solution relates to the field of electronic technology, in particular to a voltage consistency detection method and device, and a voltage equalization method and device.

【Background technique】

Pure electric buses have the advantages of no pollution and low noise, so the development prospects are very broad. The battery system is the primary key to the development of pure electric buses. Both the power system and energy storage system of a pure electric bus need the support of a battery system.

In order to improve the overcurrent capacity of the battery system, many pure electric bus power battery systems and energy storage battery systems are now connected in parallel with multi-branch battery systems. The following takes a two-branch parallel battery system as an example for illustration.

Please refer to FIG. 1 , which is an example diagram of parallel connection of two branch battery systems. As shown in Figure 1, branch 1 is composed of battery box Pack1-1, battery box Pack1-2 ... battery box Pack1-(n-1), battery box Pack1-n in series, and branch 2 is composed of battery box Pack2-1 , battery box Pack2-2...battery box Pack2-(n-1), battery box Pack2-n, branch 1 and branch 2 are connected in parallel to form a two-branch parallel battery system. Among them, the voltage of branch 1 is U1, and the voltage of branch 2 is U2. In the process of assembly and after-sales maintenance, when the two branches are connected in parallel (the MSD (Manual Service Disconnect, manual maintenance switch) of Pack1-1 is used as the last connection point in parallel), if U1≠U2, because the internal resistance of the battery and the high-voltage connection resistance between the batteries are small, the high-voltage branch will charge the low-voltage branch with high current, and the MSD of Pack1-1 fire and other safety risks.

Therefore, before the parallel connection of the battery system, it is necessary to perform a consistency check on the branch voltages of the multi-branch parallel battery system (ie, the voltage of the branch battery system). Consistency detection refers to detecting whether each branch battery system to be connected in parallel meets the parallel connection conditions, and if so, each branch battery system can be connected in parallel. If not, it is necessary to equalize the branch circuit voltage so that each branch circuit after equalization meets the parallel connection condition.

In the prior art, the scheme for detecting the voltage consistency of the branches of the multi-branch parallel battery system is as follows: perform two-two detection on each branch in the multi-branch parallel battery system, measure the voltage difference between the two branches with a voltmeter, and then Compare the measured voltage difference with a fixed voltage difference threshold. If the measured voltage difference is greater than the voltage difference threshold, it is determined that the two branches do not meet the parallel connection conditions and cannot be connected in parallel. If the measured voltage difference is smaller than the voltage difference threshold threshold, it is determined that the two branches meet the conditions for parallel connection and can be connected in parallel.

Due to the different specifications and parameters of different battery systems, only a fixed voltage difference threshold is used to judge whether parallel connection is possible. There are the following problems: If the voltage difference threshold is small, it will lead to many multi-branch battery systems that do not need to be balanced. It is necessary to perform voltage equalization before parallel connection of branch circuits, which wastes manpower and material resources; if the voltage difference threshold is large, there is a risk of misjudgment, which will lead to high current charging or ignition risks.

It can be seen that the branch voltage consistency detection scheme of the multi-branch parallel battery system in the prior art either causes some battery systems that can actually be paralleled to be paralleled after equalization, or makes some battery systems that cannot actually be paralleled directly connected in parallel And cause safety risk, the accuracy of detection is relatively low.

【Content of invention】

In view of this, the embodiment of this solution provides a voltage consistency detection method and device, and a voltage equalization method and device to solve the problem of relatively low detection accuracy of branch voltage consistency in a multi-branch parallel battery system in the prior art. question.

In the first aspect, the embodiment of this solution provides a voltage consistency detection method, which is applied to the first battery system and the second battery system of a multi-branch parallel battery system, and the method includes:

detecting a voltage difference between the first battery system and the second battery system;

detecting an energy difference between the first battery system and the second battery system;

Based on the voltage difference and the energy difference, it is judged whether the voltage consistency between the first battery system and the second battery system is met, wherein, when the voltage consistency is met, the first battery system and the The second battery system is connected in parallel.

According to the above aspect and any possible implementation manner, an implementation manner is further provided, based on the voltage difference and the energy difference, it is judged whether the voltage between the first battery system and the second battery system conforms to The steps for consistency include:

If the voltage difference is greater than the voltage difference threshold, it is detected that the high-voltage system of both the first battery system and the second battery system charges the low-voltage system of the two with a constant current value through a variable resistor. The resistance value of the variable resistor;

According to the resistance value, it is judged whether the voltage consistency between the first battery system and the second battery system is met.

According to the above aspect and any possible implementation manner, an implementation manner is further provided, the step of judging whether the voltage consistency between the first battery system and the second battery system according to the resistance value includes:

If the resistance value is greater than the resistance value threshold, it is determined that the voltage consistency between the first battery system and the second battery system does not meet, and the first battery system and the second battery system are not connected in parallel.

According to the above aspect and any possible implementation manner, an implementation manner is further provided, the step of judging whether the voltage consistency between the first battery system and the second battery system according to the resistance value includes:

If the resistance value is less than the resistance value threshold, detecting the charging current when the high-voltage system directly charges the low-voltage system;

It is judged according to the charging current whether the voltage consistency between the first battery system and the second battery system is met.

According to the above aspect and any possible implementation manner, an implementation manner is further provided, the step of judging whether the voltage consistency between the first battery system and the second battery system according to the charging current includes:

If the charging current is greater than the current threshold, it is judged that the voltage consistency between the first battery system and the second battery system does not meet, and the first battery system and the second battery system are not connected in parallel;

Alternatively, if the charging current is less than the current threshold, it is determined that the voltage consistency between the first battery system and the second battery system is met.

According to the above aspect and any possible implementation manner, an implementation manner is further provided, based on the voltage difference and the energy difference, it is judged whether the voltage between the first battery system and the second battery system conforms to The steps for consistency include:

If the voltage difference is smaller than the voltage difference threshold, it is determined that the voltage consistency between the first battery system and the second battery system is met.

According to the above aspect and any possible implementation, an implementation is further provided, at most one of the first battery system and the second battery system is composed of two or more battery systems connected in parallel battery system.

In the second aspect, the embodiment of this solution provides a voltage consistency detection device, which is applied to the first battery system and the second battery system of a multi-branch parallel battery system, and the device includes:

a detection module, configured to detect a voltage difference and an energy difference between the first battery system and the second battery system;

A determining module, configured to judge whether the voltage consistency between the first battery system and the second battery system is met based on the voltage difference and the energy difference, wherein, when the voltage consistency is met, the first The battery system is connected in parallel with the second battery system.

According to the above-mentioned aspect and any possible implementation manner, an implementation manner is further provided, the determining module is configured to determine the voltage difference based on the voltage difference and the energy between the first battery system and the second battery system Poor, when judging whether the voltage consistency between the first battery system and the second battery system is met, it is specifically used for:

If the voltage difference is greater than the voltage difference threshold, it is detected that the high-voltage system of both the first battery system and the second battery system charges the low-voltage system of the two with a constant current value through a variable resistor. The resistance value of the variable resistor;

According to the resistance value, it is judged whether the voltage consistency between the first battery system and the second battery system is met.

According to the above aspect and any possible implementation manner, an implementation manner is further provided, the determination module is configured to determine whether the first battery system and the second battery system meet the requirements according to the resistance value. For voltage consistency, it is specifically used for:

If the resistance value is greater than the resistance value threshold, it is determined that the voltage consistency between the first battery system and the second battery system does not meet, and the first battery system and the second battery system are not connected in parallel.

According to the above aspect and any possible implementation manner, an implementation manner is further provided, the determination module is configured to judge whether the first battery system and the second battery system meet the requirements according to the resistance value. For voltage consistency, it is specifically used for:

If the resistance value is less than the resistance value threshold, detecting the charging current when the high-voltage system directly charges the low-voltage system;

It is judged according to the charging current whether the voltage consistency between the first battery system and the second battery system is met.

According to the above aspect and any possible implementation manner, an implementation manner is further provided, the determination module is configured to determine whether the first battery system and the second battery system conform to each other according to the charging current. For voltage consistency, it is specifically used for:

If the charging current is greater than the current threshold, it is judged that the voltage consistency between the first battery system and the second battery system does not meet, and the first battery system and the second battery system are not connected in parallel;

Alternatively, if the charging current is less than the current threshold, it is determined that the voltage consistency between the first battery system and the second battery system is met, and the first battery system and the second battery system are connected in parallel.

According to the above aspect and any possible implementation manner, an implementation manner is further provided, the determination module is configured to determine the first battery system and the energy difference based on the voltage difference and the first battery system When the voltage consistency between the battery system and the second battery system is met, it is specifically used for:

If the voltage difference is smaller than the voltage difference threshold, it is determined that the voltage consistency between the first battery system and the second battery system is met.

According to the above aspect and any possible implementation, an implementation is further provided, at most one of the first battery system and the second battery system is composed of two or more battery systems connected in parallel battery system.

The voltage consistency detection method and the voltage consistency detection device provided by the embodiments of the present invention take into account the factors of different internal resistance values of different battery systems, and comprehensively judge the difference between the battery systems based on the voltage difference and energy difference between the battery systems. Whether it conforms to voltage consistency improves the accuracy of voltage consistency detection.

In the third aspect, the embodiment of this solution provides a voltage equalization method, which is applied to the first battery system and the second battery system of a multi-branch parallel battery system, and the voltage of the first battery system is greater than that of the second battery system. voltage, including:

Make the first battery system charge the second battery system with a constant current value through a variable resistor, which is denoted as a first charging circuit;

detecting the resistance value of the variable resistor;

If the resistance value of the variable resistor is less than the resistance value threshold, disconnect the first charging circuit, make the first battery system directly charge the second battery system, which is recorded as the second charging circuit, and detect the The charging current of the second charging circuit;

Determine whether to stop charging according to the detected charging current.

According to the above aspect and any possible implementation, an implementation is further provided, the step of judging whether to stop charging according to the detected charging current includes:

If the detected charging current is greater than the current threshold, continue to charge the first battery system to the second battery system through the second charging circuit;

Alternatively, if the detected charging current is less than the current threshold, stop charging the second battery system.

According to the above aspects and any possible implementation, an implementation is further provided, which also includes:

If the resistance of the variable resistor is greater than the resistance threshold, continue to charge the first battery system to the second battery system through the first charging circuit.

According to the above aspect and any possible implementation, an implementation is further provided, at most one of the first battery system and the second battery system is composed of two or more battery systems connected in parallel battery system.

In the fourth aspect, the embodiment of this solution provides a voltage equalization device between battery systems, which is applied to the first battery system and the second battery system of a multi-branch parallel battery system, and the voltage of the first battery system is greater than that of the first battery system. The voltage of the two-battery system, including:

The first charging module is used to make the first battery system charge the second battery system with a constant current value through a variable resistor, which is denoted as a first charging circuit;

a resistance detection module, configured to detect the resistance of the variable resistor;

The second charging module is configured to disconnect the first charging circuit when the resistance value of the variable resistor is less than the resistance value threshold, so that the first battery system can directly charge the second battery system, which is denoted as a second charging circuit, and detecting the charging current of the second charging circuit;

A switch module, configured to judge whether to stop charging according to the charging current detected by the second charging module.

According to the above-mentioned aspect and any possible implementation manner, an implementation manner is further provided, the switch module is configured to determine whether to stop charging according to the detected charging current, and is specifically configured to:

If the detected charging current is greater than the current threshold, continue to charge the first battery system to the second battery system through the second charging circuit;

Alternatively, if the detected charging current is less than the current threshold, stop charging the second battery system.

According to the above aspects and any possible implementation, an implementation is further provided, which also includes:

The second switch module is configured to continue charging the first battery system to the second battery system through the first charging circuit when the resistance value of the variable resistor is greater than the resistance value threshold.

According to the above aspect and any possible implementation, an implementation is further provided, at most one of the first battery system and the second battery system is composed of two or more battery systems connected in parallel battery system.

The voltage equalization method and voltage equalization device provided by the embodiments of the present invention can monitor the equalization process, stop charging in time after the equalization reaches the standard, and prevent overcharging, thereby improving the safety performance of the equalization process.

In the fifth aspect, the embodiment of this solution provides a battery system detection and equalization system, the system includes a voltage consistency detection device and a voltage equalization device between battery systems,

The voltage consistency detection device is any voltage consistency detection device described in the second aspect,

The voltage equalization device between battery systems is any one of the voltage equalization devices between battery systems described in the fourth aspect.

In the sixth aspect, the embodiment of this solution provides a detection and equalization circuit for a battery system, wherein the circuit includes a first switch, a second switch, a variable resistor, a controller, a voltage detection device, a current detection device, Positive interface and negative interface, both ends of the voltage detection device are respectively connected to the positive interface and the negative interface, the current detection device and the second switch are connected in series between the positive interface and the negative interface Between, the series circuit composed of the first switch and the variable resistor is connected in parallel with the second switch, the first switch, the second switch, the variable resistor, the voltage detection device, the The controllers of the current detection equipment are respectively connected to the controllers through low-voltage transmission lines, and other connecting lines in the circuit except the low-voltage transmission lines are high-voltage transmission lines.

According to the foregoing aspect and any possible implementation manner, an implementation manner is further provided, wherein the variable resistor is a program-controlled load.

The battery system detection and equalization circuit provided by the embodiment of the present invention comprehensively judges whether the battery systems meet the voltage consistency through the voltage difference and energy difference between the battery systems, improves the accuracy of the voltage consistency detection, and can Monitor the equalization process of the battery system, and stop charging in time after the equalization reaches the standard to prevent overcharging, thereby improving the safety performance of the equalization process.

【Description of drawings】

In order to more clearly illustrate the technical solutions of the embodiments of this solution, the following will briefly introduce the drawings that need to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of this solution. For this Those of ordinary skill in the art can also obtain other drawings based on these drawings without paying creative labor.

Figure 1 is an example diagram of a parallel connection of a two-branch battery system.

FIG. 2 is a schematic flowchart of a method for detecting voltage consistency in Embodiment 1 of the present invention.

FIG. 3 is a functional block diagram of a voltage consistency detection device in Embodiment 2 of the present invention.

FIG. 4 is a schematic flowchart of a voltage equalization method in Embodiment 3 of the present invention.

FIG. 5 is a functional block diagram of a voltage equalization device in Embodiment 4 of the present invention.

FIG. 6 is a circuit diagram of the detection and equalization circuit of the battery system in the sixth embodiment of the present invention.

【detailed description】

In order to better understand the technical solution of this solution, the embodiments of this solution will be described in detail below in conjunction with the accompanying drawings.

It should be clear that the described embodiments are only some of the embodiments of this solution, not all of them. Based on the embodiments in this solution, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of this solution.

The terms used in the embodiments of this solution are only for the purpose of describing specific embodiments, and are not intended to limit this solution. The singular forms "a", "said" and "the" used in the present embodiments and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

It should be understood that the term "and/or" used herein is only an association relationship describing associated objects, which means that there may be three relationships, for example, A and/or B, which may mean that A exists alone, and A and B exist simultaneously. B, there are three situations of B alone. In addition, the character "/" in this article generally indicates that the contextual objects are an "or" relationship.

Depending on the context, the word "if" as used herein may be interpreted as "at" or "when" or "in response to determining" or "in response to detecting". Similarly, depending on the context, the phrases "if determined" or "if detected (the stated condition or event)" could be interpreted as "when determined" or "in response to the determination" or "when detected (the stated condition or event) )" or "in response to detection of (a stated condition or event)".

Embodiment one

An embodiment of the present invention provides a voltage consistency detection method, which can be applied to the first battery system and the second battery system of a multi-branch parallel battery system.

FIG. 2 is a schematic flowchart of a method for detecting voltage consistency in Embodiment 1 of the present invention. As shown in Figure 2, in this embodiment, the voltage consistency detection method includes the following steps:

S201, detecting the voltage difference between the first battery system and the second battery system;

If the first battery system and the second battery system are connected in parallel, disconnect the high-voltage output of the parallel battery system composed of the first battery system and the second battery system, and then connect the circuit composed of the first battery system and the second battery system Disconnect at any point, measure the voltage difference between the two points at the disconnected point, and the voltage difference is the voltage difference between the first battery system and the second battery system. For example, in Figure 1, the MSD of Pack1-1 is used as the last parallel connection point. After the MSD is disconnected, measure the voltage between the two terminals of the MSD to obtain the voltage difference between the two battery systems.

S202, detecting the energy difference between the first battery system and the second battery system;

S203. Based on the voltage difference and the energy difference, judge whether the voltage consistency between the first battery system and the second battery system is met, wherein, if the voltage consistency is met, the first battery system and the second battery system are connected in parallel.

Considering that different battery systems have different internal resistance values, it is not possible to judge whether to connect them in parallel based only on a fixed voltage difference threshold. In this embodiment, according to the voltage difference and energy difference between the first battery system and the second battery system, it is judged whether the voltage consistency between the first battery system and the second battery system is met, and if the voltage consistency is met, the It is determined that the first battery system and the second battery system can be connected in parallel. If the voltage consistency is not met, it is determined that the first battery system and the second battery system cannot be connected in parallel, and voltage equalization is required.

Wherein, the energy difference is related to the charging current when the high-voltage system directly charges the low-voltage system between the first battery system and the second battery system. For the convenience of description, this charging current is called direct charging current. If the energy difference is too large, the direct charging current will be very large, which will cause a safety risk of ignition at the MSD. If the energy difference is relatively small, the direct charging current will be relatively small. If the direct charging current is below a current threshold, it will be It will not cause or hardly cause the safety risk of sparking at the MSD. At this time, even if the voltage difference between the first battery system and the second battery system is greater than the set voltage difference threshold, they can be connected in parallel, because at this time The first battery system is connected in parallel with the second battery system, even if there is a direct charging current for the high-voltage system to charge the low-voltage system, the direct charging current will not cause a safety risk.

Accordingly, in a specific application, a small voltage difference threshold can be set, and some battery systems whose voltage difference is smaller than the voltage difference threshold are determined as battery systems that can be connected in parallel through the voltage difference threshold. Since the voltage difference threshold is relatively small, the consistency detection accuracy of these battery systems whose voltage differences are smaller than the voltage difference threshold is relatively high. For the battery system whose voltage difference is greater than the voltage difference threshold, it is further determined whether it can be connected in parallel according to its energy difference, or whether it meets the voltage consistency.

In a specific implementation process, based on the voltage difference and energy difference, the step of judging whether the voltage consistency between the first battery system and the second battery system is consistent further includes: if the voltage difference is greater than the voltage difference threshold, detecting the first battery system The resistance value of the variable resistance when the high-voltage system in both the high-voltage system and the second battery system charges the low-voltage system in the two with a constant current value through the variable resistance; judge the difference between the first battery system and the second battery system according to the resistance value Whether it meets the voltage consistency.

Wherein, the variable resistor may be a program-controlled resistor.

When the high-voltage system between the first battery system and the second battery system charges the low-voltage system of the two with a constant current value through a variable resistor (for the convenience of description, this charging circuit is recorded as the first charging circuit), because If the current is constant, the greater the resistance value of the variable resistor, the greater the energy consumed on the variable resistor (because the energy consumed on the variable resistor W=I ² R), the greater the energy consumed on the variable resistor, it means The greater the energy difference between the first battery system and the second battery system. When the current value is constant, the energy consumed on the variable resistor is proportional to the resistance value of the variable resistor, therefore, when the current value is constant, the energy difference between the first battery system and the second battery system is proportional to the variable resistor proportional to the resistance value.

Wherein, the high-voltage system between the first battery system and the second battery system charges the low-voltage system of the two with a constant current value through a variable resistor, which can be set to the allowable value in the charging circuit through the variable resistor. The maximum current value, for the convenience of description, the maximum current value is recorded as the first current threshold I10.

In this way, the resistance threshold R0 can be further set, so that the maximum energy allowed to be consumed on the variable resistor is equal to I10*I10*R0. When the high-voltage system between the first battery system and the second battery system charges the low-voltage system of the two with a constant current value I10 through the variable resistor, the energy consumed by the variable resistor is proportional to the resistance value of the variable resistor.

Further, in a specific implementation process, the step of judging whether the voltage consistency between the first battery system and the second battery system according to the resistance value further includes: if the resistance value is greater than the resistance value threshold, judging whether the first battery system and the second battery system meet the voltage consistency. The voltage consistency between the second battery systems is not met, and the first battery system and the second battery system are not connected in parallel.

Further, in a specific implementation process, the step of judging whether the voltage consistency between the first battery system and the second battery system according to the resistance value further includes: if the resistance value is less than the resistance value threshold, detecting that the high-voltage system is directly connected to the low-voltage The charging current when the system is charging; according to the charging current, it is judged whether the voltage consistency between the first battery system and the second battery system is met.

For the case where the resistance value is less than the resistance value threshold, it means that the energy difference between the first battery system and the second battery system is relatively small, but whether the energy difference is so small that it is not safe to connect the first battery system and the second battery system in parallel The degree of risk still needs further judgment. At this time, the degree of danger of the energy difference can be judged by the magnitude of the charging current when the high-voltage system directly charges the low-voltage system. Obviously, the smaller the direct charging current, the smaller the energy difference and the smaller the risk of parallel connection, and vice versa. For this reason, a second current threshold can be set. When the direct charging current is less than the second current threshold, it means that the energy difference is very small, which is not enough to cause a safety risk in parallel connection. At this time, it is considered that the first battery system and the second battery system meet The voltage consistency can be connected in parallel. If the direct charging current is greater than the second current threshold, it means that the energy difference is relatively large, which is enough to cause a safety risk in parallel connection. At this time, it is considered that the voltage consistency between the first battery system and the second battery system does not meet. Cannot be connected in parallel.

Therefore, further, in a specific implementation process, the step of judging whether the voltage consistency between the first battery system and the second battery system according to the charging current further includes: if the charging current is greater than the current threshold (that is, the above-mentioned the second current threshold), it is judged that the voltage consistency between the first battery system and the second battery system is not met, and the first battery system and the second battery system are not connected in parallel; or, if the charging current is less than the current threshold, it is judged that the first battery system The voltage consistency between the battery system and the second battery system is met, and the first battery system and the second battery system are connected in parallel.

In a specific implementation process, based on the voltage difference and the energy difference, the step of judging whether the voltage consistency between the first battery system and the second battery system also includes: if the voltage difference is less than the voltage difference threshold, judging whether the first battery system Comply with the voltage consistency between the second battery system.

In a specific implementation process, at most one of the first battery system and the second battery system is a battery system composed of more than two battery systems connected in parallel. That is to say, the parallel battery system composed of the first battery system and the second battery system may be a two-branch parallel battery system, or a multi-branch parallel battery system such as a three-branch parallel battery system. For a multi-branch parallel battery system with more than three branches, it can be regarded as a two-branch battery system composed of a single-branch non-parallel battery system and a two-branch parallel battery system, so that the present invention can be applied The consistency detection method in the embodiment is tested. Of course, the premise is that the single-branch battery systems in the parallel-connected battery systems with more than two branches have been tested for consistency and can be parallel-connected battery systems.

The voltage consistency detection method provided by the embodiment of the present invention takes into account the factors of different internal resistance values of different battery systems, and comprehensively judges whether the battery systems meet the voltage consistency through the voltage difference and energy difference between the battery systems, The accuracy of voltage consistency detection is improved.

In order to realize the steps in the foregoing embodiments of the voltage consistency detection method, embodiments of the present invention further provide embodiments of a voltage consistency detection device.

Embodiment two

This embodiment proposes a voltage consistency detection device, which is applied to the first battery system and the second battery system of a multi-branch parallel battery system.

FIG. 3 is a functional block diagram of a voltage consistency detection device in Embodiment 2 of the present invention. As shown in Figure 3, in this embodiment, the voltage consistency detection device also includes:

A detection module 310, configured to detect the voltage difference and energy difference between the first battery system and the second battery system;

The determining module 320 is configured to judge whether the voltage consistency between the first battery system and the second battery system is met based on the voltage difference and the energy difference, wherein, when the voltage consistency is met, the first battery system and the second battery system are connected in parallel .

In a specific implementation process, the determination module 320 is used to determine whether the voltage consistency between the first battery system and the second battery system is based on the voltage difference and the energy difference, specifically: if the voltage difference is greater than The voltage difference threshold value detects the resistance value of the variable resistor when the high-voltage system of the first battery system and the second battery system charges the low-voltage system of the two with a constant current value through the variable resistor; judge the first battery according to the resistance value Whether the voltage consistency between the battery system and the second battery system is met.

Further, in a specific implementation process, the determination module 320 is used to determine whether the voltage consistency between the first battery system and the second battery system is met according to the resistance value, specifically to: if the resistance value is greater than the resistance value threshold , judging that the voltage consistency between the first battery system and the second battery system does not meet, and the first battery system and the second battery system are not connected in parallel.

Further, in a specific implementation process, the determination module 320 is used to determine whether the voltage consistency between the first battery system and the second battery system is met according to the resistance value, specifically to: if the resistance value is less than the resistance value threshold , detecting the charging current when the high-voltage system directly charges the low-voltage system; judging whether the voltage consistency between the first battery system and the second battery system is met according to the charging current.

Further, in a specific implementation process, the determining module 320 is configured to determine whether the voltage consistency between the first battery system and the second battery system is met according to the charging current, specifically: if the charging current is greater than the current threshold, Judging that the voltage consistency between the first battery system and the second battery system does not meet, the first battery system and the second battery system are not connected in parallel; or, if the charging current is less than the current threshold, judge the first battery system and the second battery system The voltage consistency between the first battery system and the second battery system is connected in parallel.

In a specific implementation process, the determining module 320 is used to determine whether the voltage consistency between the first battery system and the second battery system is met based on the voltage difference and the energy difference, specifically: if the voltage difference is less than the voltage difference The threshold is used to determine the voltage consistency between the first battery system and the second battery system.

Wherein, at most one of the first battery system and the second battery system is a battery system composed of more than two battery systems connected in parallel.

Since the voltage consistency detection device in this embodiment can execute the voltage consistency detection method in the first embodiment above, for the parts not described in detail in this embodiment, you can refer to the relevant description of the voltage consistency detection method in the first embodiment .

The voltage consistency detection device provided by the embodiment of the present invention takes into account the factors of different internal resistance values of different battery systems, and comprehensively judges whether the battery systems meet the voltage consistency through the voltage difference and energy difference between the battery systems, The accuracy of voltage consistency detection is improved.

Embodiment three

This embodiment provides a voltage equalization method, which is applied to a first battery system and a second battery system of a multi-branch parallel battery system, wherein the voltage of the first battery system is greater than the voltage of the second battery system.

FIG. 4 is a schematic flowchart of a voltage equalization method in Embodiment 3 of the present invention. As shown in Figure 4, in this embodiment, the voltage equalization method also includes the following steps:

S401, make the first battery system charge the second battery system with a constant current value through the variable resistor, which is recorded as the first charging circuit;

Among them, the constant current value is the smaller value of the maximum current value that the branch battery system can withstand (denoted as Ipmax) and the maximum current value that the balancing device can withstand (denoted as Icmax).

S402, detecting the resistance value of the variable resistor;

S403, if the resistance value of the variable resistor is less than the resistance value threshold, disconnect the first charging circuit, make the first battery system charge the second battery system directly, record it as the second charging circuit, and detect the charging current of the second charging circuit ;

The resistance value of the variable resistor is less than the resistance value threshold, indicating that the energy difference between the first battery system and the second battery system has been small to a certain extent, but whether the energy difference is small enough to connect the first battery system and the second battery system in parallel When it is not enough to cause a safety risk, it also needs to be determined according to the magnitude of the charging current that the first battery system directly charges the second battery system.

S404, judging whether to stop charging according to the detected charging current.

In a specific implementation process, the step of judging whether to stop charging according to the detected charging current further includes: if the detected charging current is greater than the current threshold, continue to charge the first battery system to the second battery system through the second charging circuit ; Or, if the detected charging current is less than the current threshold, stop charging the second battery system.

The charging current of the first battery system directly charging the second battery system is greater than the current threshold, indicating that the energy difference between the first battery system and the second battery system is not small enough to be insufficient when the first battery system and the second battery system are connected in parallel To the extent that it poses a security risk, the balancing needs to continue. If the charging current of the first battery system directly charging the second battery system is less than the current threshold, it means that the energy difference between the first battery system and the second battery system is too small to be insufficient when the first battery system and the second battery system are connected in parallel To the extent that a safety risk arises, no further equalization is required, at which point charging of the second battery system can be stopped to stop equalization.

In a specific implementation process, the voltage equalization method further includes: if the resistance value of the variable resistor is greater than the resistance value threshold, continue to charge the first battery system to the second battery system through the first charging circuit.

Wherein, at most one of the first battery system and the second battery system is a battery system composed of more than two battery systems connected in parallel.

The voltage equalization method provided by the embodiment of the present invention can monitor the equalization process, stop charging in time after the equalization reaches the standard, and prevent overcharging, thereby improving the safety performance of the equalization process.

Embodiment four

In order to realize the steps in the foregoing embodiments of the voltage equalization method, embodiments of the present invention also provide embodiments of voltage equalization devices.

This embodiment provides a voltage equalization device, which is applied to a first battery system and a second battery system of a multi-branch parallel battery system, and the voltage of the first battery system is greater than the voltage of the second battery system.

FIG. 5 is a functional block diagram of a voltage equalization device in Embodiment 4 of the present invention. As shown in Figure 5, in this embodiment, the voltage equalization device includes:

The first charging module 510 is used to charge the first battery system to the second battery system at a constant current value through a variable resistor, which is denoted as a first charging circuit;

Resistance detection module 520, used to detect the resistance of the variable resistor;

The second charging module 530 is used to disconnect the first charging circuit when the resistance value of the variable resistor is less than the resistance value threshold, so that the first battery system can directly charge the second battery system, denoted as the second charging circuit, and detect The charging current of the second charging circuit;

The first switch module 540 is used for judging whether to stop charging according to the charging current detected by the second charging module 530 .

In a specific implementation process, the first switch module 540 is used to determine whether to stop charging according to the detected charging current, and is specifically used to: if the detected charging current is greater than the current threshold, continue to make the first battery system pass through the first battery system. The second charging circuit charges the second battery system; or, if the detected charging current is less than the current threshold, stops charging the second battery system.

In a specific implementation process, the voltage equalization device also includes:

The second switch module is configured to continue charging the first battery system to the second battery system through the first charging circuit when the resistance value of the variable resistor is greater than the resistance value threshold.

Wherein, at most one of the first battery system and the second battery system is a battery system composed of two or more battery systems connected in parallel.

Since the voltage equalization device in this embodiment can execute the voltage equalization method in the aforementioned third embodiment, for parts not described in detail in this embodiment, reference may be made to the relevant description of the voltage equalization method in the aforementioned first embodiment.

The voltage equalization device provided by the embodiments of the present invention can monitor the equalization process, stop charging in time after the equalization reaches the standard, and prevent overcharging, thereby improving the safety performance of the equalization process.

It should be noted that the voltage consistency detection method in Embodiment 1 and the voltage equalization method in Embodiment 3 can be used in combination, and the voltage consistency detection method in Embodiment 1 is used to detect the voltage consistency of the battery system. The battery system that does not have voltage consistency is obtained, and then the voltage equalization method in the third embodiment is used for equalization.

For example, assume that there are 4 single branch non-parallel battery systems: battery system 1 has a voltage of 50 volts, battery system 2 has a voltage of 80 volts, battery system 3 has a voltage of 100 volts, and battery system 4 has a voltage of 120 volts.

First, the battery system 1 and the battery system 2 are detected by using the voltage consistency detection method of the first embodiment, and the detection result is that the battery system 1 and the battery system 2 do not have voltage consistency;

Then apply the voltage equalization method of Embodiment 3 to perform voltage equalization processing on the battery system 1 and the battery system 2, and after equalization, the voltages of the battery system 1 and the battery system 2 both become 60 volts;

The balanced battery system 1 and battery system 2 are connected in parallel to form a battery system 11, and the battery system 11 and battery system 3 are tested using the voltage consistency detection method of the first embodiment. The test result is that the battery system 1 and the battery system 2 are not With voltage consistency;

Apply the voltage equalization method of Embodiment 3 to perform voltage equalization processing on the battery system 11 and the battery system 3, and after equalization, the voltages of the battery system 11 and the battery system 3 both become 70 volts;

The balanced battery system 11 and battery system 3 are connected in parallel to form a battery system 12, and the battery system 12 and battery system 4 are tested using the voltage consistency detection method of Embodiment 1. The test result is that the battery system 11 and the battery system 4 are not With voltage consistency;

Apply the voltage equalization method of Embodiment 3 to perform voltage equalization processing on the battery system 12 and the battery system 4, and after equalization, the voltages of the battery system 12 and the battery system 4 both become 75 volts;

Finally, the balanced battery system 12 and the battery system 4 are connected in parallel, so that the voltage consistency detection and equalization of multiple branch battery systems are realized.

Embodiment five

This embodiment provides a detection and equalization system for a battery system, which includes a voltage consistency detection device and a voltage equalization device between battery systems.

Wherein, the voltage consistency detection device is any voltage consistency detection device in the second embodiment above,

Wherein, the voltage equalization device is any voltage equalization device in the foregoing fourth embodiment.

Embodiment six

This embodiment provides a detection and equalization circuit for a battery system.

FIG. 6 is a circuit diagram of the detection and equalization circuit of the battery system in the sixth embodiment of the present invention. As shown in FIG. 6, in this embodiment, the detection and equalization circuit of the battery system includes a first switch S1, a second switch S2, a variable resistor, a controller, a voltage detection device, a current detection device, a positive interface, and a negative interface. Wherein, the two ends of the voltage detecting device are respectively connected to the positive terminal and the negative terminal, the current detecting device and the second switch S2 are connected in series between the positive terminal and the negative terminal, the series circuit composed of the first switch S1 and the variable resistor is connected to the second The switch S2 is connected in parallel, and the first switch S1, the second switch S2, the variable resistor, the voltage detection device, and the current detection device controller are respectively connected to the controller through a low-voltage transmission line, and other connection lines in this circuit except the low-voltage transmission line are all high-voltage Transmission line.

Wherein, the variable resistor can be a program-controlled load.

After installing the detection and equalization system of the battery system described in Embodiment 5 in the controller, the detection and equalization circuit of the battery system in this embodiment can be applied to realize the voltage consistency detection of the battery system and the detection of The battery system with voltage consistency performs voltage equalization. The following takes the two-branch parallel battery system shown in Figure 1 as an example to illustrate the process and principle of detection and equalization as follows:

1) First set the parameters:

Voltage difference threshold: ΔU0

Precharge circuit resistance threshold: R0;

Current threshold of the circuit where S1 is located: I10;

Current threshold of the circuit where S2 is located: I20;

The maximum current value that the branch battery system can withstand: Ipmax;

The maximum current value that the equalizing device can withstand: Icmax.

2) Equipment connection: For the two-branch parallel battery system shown in Figure 1, disconnect the external high-voltage output of the positive pole of the battery system and the negative pole of the battery system, use the MSD of Pack1-1 as the final parallel connection point, and connect the positive pole interface and the negative pole interface. Connect with the MSD interface of port Pack1-1.

3) Voltage consistency detection to judge whether it can be connected in parallel:

3.1) Voltage difference detection: use voltage detection equipment to detect the voltage difference ΔU between Pack1 and Pack2;

3.2) Voltage difference judgment: when ΔU≤ΔU0, it is judged that Pack1 and Pack2 conform to the voltage consistency, meet the branch parallel condition, end the judgment process, and inform the user that the battery system meets the branch parallel condition; when ΔU＞ΔU0, enter the step 3.3.

3.3) When ΔU>ΔU0, close S1 in the pre-charging circuit, adjust the variable resistor until the circuit current I1=I10 where S1 is located, and record the resistance value R of the variable resistor at this time.

3.4) Judgment of the resistance value R of the variable resistor: When R>R0, it is judged that Pack1 and Pack2 do not meet the voltage consistency, and the battery system does not meet the branch parallel connection conditions, and enter the branch voltage equalization process in step 4 below; when R≤ R0, go to step 3.5.

3.5) When R≤R0, close the switch S2 in the pre-charging circuit, measure the current I2 of the circuit where the switch S2 is located, and turn off the switch S1 and the switch S2 after obtaining I2.

3.6) Judgment of current value I2: When I2>I20, it is judged that Pack1 and Pack2 do not meet the voltage consistency, and the battery system does not meet the condition of branch parallel connection, and enter the branch voltage equalization process in step 4 below; when I2≤I20, judge Pack1 The voltage consistency with Pack2 is met, the battery system meets the branch circuit parallel connection conditions, the judgment process ends, and the customer is notified that the battery system meets the branch circuit parallel connection conditions.

4) Branch voltage balance:

4.1) When the branch parallel condition is not satisfied and the branch equalization process is entered, the user may first be notified that the battery system does not meet the parallel condition, and enter step 4.2.

4.2) Close the switch S1, adjust the variable resistor, stabilize the current I1 at the minimum value of Ipmax and Icmax, perform constant current charging, and record the resistance value R of the variable resistor during the constant current charging process.

4.3) Judgment of resistance value R: when R>R0, return to step 4.2 and continue charging with constant current; when R≤R0, proceed to step 4.4.

4.4) When R≤R0, close the switch S2, and record the current I2 of the circuit where the switch S2 is located.

4.5) Judgment of current value I2: when I2>I20, return to step 4.4, and continue to keep S2 closed; when I2≤I20, disconnect S1 and S2, end the equalization process, and judge that the battery system meets the branch parallel condition.

The battery system detection and equalization circuit provided by the embodiment of the present invention comprehensively judges whether the battery systems meet the voltage consistency through the voltage difference and energy difference between the battery systems, improves the accuracy of the voltage consistency detection, and can Monitor the equalization process of the battery system, and stop charging in time after the equalization reaches the standard to prevent overcharging, thereby improving the safety performance of the equalization process.

The above is only a preferred embodiment of this program, and is not intended to limit this program. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this program should be included in this program within the scope of protection.

Claims (25)

1. a kind of voltage consistency detecting method, the first battery system being applied in multiple branch circuit batteries in parallel connection system and the second electricity Cell system, it is characterised in that methods described includes：

Detect the voltage difference of first battery system and second battery system；

Detect the energy difference of first battery system and second battery system；

Based on the voltage difference and the energy difference, judge between first battery system and second battery system whether Meet voltage uniformity, wherein, when voltage uniformity is met, first battery system and second battery system are carried out simultaneously Connection.

2. method according to claim 1, it is characterised in that based on the voltage difference and the energy difference, judges described Whether the step of meeting voltage uniformity between first battery system and second battery system includes：

If the voltage difference is more than in both voltage difference threshold value, detection first battery system and described second battery system The electricity of variable resistor when high-pressure system is charged to the low-pressure system in both by variable resistor with constant current value Resistance；

Judge whether to meet voltage between first battery system and second battery system consistent according to the resistance value Property.

3. method according to claim 2, it is characterised in that according to the resistance value judge first battery system with Whether the step of meeting voltage uniformity between second battery system includes：

If the resistance value is more than resistance value threshold value, judge not being inconsistent between first battery system and second battery system Voltage uniformity is closed, first battery system and second battery system do not carry out parallel connection.

4. method according to claim 2, it is characterised in that according to the resistance value judge first battery system with Whether the step of meeting voltage uniformity between second battery system includes：

If the resistance value is less than resistance value threshold value, charging when detecting that the high-pressure system directly charges to the low-pressure system Electric current；

Judge whether meet voltage one between first battery system and second battery system according to the charging current Cause property.

5. method according to claim 4, it is characterised in that first battery system is judged according to the charging current Whether the step of meeting voltage uniformity between second battery system includes：

If the charging current is more than current threshold, judge not being inconsistent between first battery system and second battery system Voltage uniformity is closed, first battery system and second battery system do not carry out parallel connection；

Or, if the charging current be less than current threshold, judge first battery system and second battery system it Between meet voltage uniformity.

6. method according to claim 1, it is characterised in that based on the voltage difference and the energy difference, judges described Whether meet voltage uniformity between first battery system and second battery system, with the step of include：

If the voltage difference is less than voltage difference threshold value, judge to meet between first battery system and second battery system Voltage uniformity.

7. method according to claim 1, it is characterised in that first battery system and second battery system two It is the battery system composed in parallel by more than two battery systems at most to have one in person.

8. a kind of voltage consistency detection device, is applied to first battery system and the second battery of multiple branch circuit batteries in parallel connection system System, it is characterised in that described device includes：

Detection module, voltage difference and energy difference for detecting first battery system and second battery system；

Determining module, for based on the voltage difference and the energy difference, judging first battery system with the described second electricity Whether voltage uniformity is met between cell system, wherein, when meeting voltage uniformity, first battery system and described second Battery system carries out parallel connection.

9. device according to claim 8, it is characterised in that the determining module is used in the voltage difference and the energy Amount is poor, when judging whether to meet voltage uniformity between first battery system and second battery system, specifically for：

If the voltage difference is more than in both voltage difference threshold value, detection first battery system and described second battery system The electricity of variable resistor when high-pressure system is charged to the low-pressure system in both by variable resistor with constant current value Resistance；

Judge whether to meet voltage between first battery system and second battery system consistent according to the resistance value Property.

10. device according to claim 9, it is characterised in that the determining module is used to sentence according to the resistance value It is disconnected when whether meeting voltage uniformity between first battery system and second battery system, specifically for：

If the resistance value is more than resistance value threshold value, judge not being inconsistent between first battery system and second battery system Voltage uniformity is closed, first battery system and second battery system do not carry out parallel connection.

11. devices according to claim 9, it is characterised in that the determining module is used to sentence according to the resistance value It is disconnected when whether meeting voltage uniformity between first battery system and second battery system, specifically for：

If the resistance value is less than resistance value threshold value, charging electricity when detecting that the high-pressure system charges to the low-pressure system Stream；

Judge whether meet voltage one between first battery system and second battery system according to the charging current Cause property.

12. devices according to claim 11, it is characterised in that the determining module is used for according to the charging current When judging whether to meet between first battery system and second battery system voltage Yi Zhi Time, specifically for：

If the charging current is more than current threshold, judge not being inconsistent between first battery system and second battery system Voltage uniformity is closed, first battery system and second battery system do not carry out parallel connection；

Or, if the charging current be less than current threshold, judge first battery system and second battery system it Between meet voltage uniformity, first battery system and second battery system carry out parallel connection.

13. devices according to claim 8, it is characterised in that the determining module be used for based on the voltage difference and The energy difference, when judging whether to meet voltage uniformity between first battery system and second battery system, tool Body is used for：

If the voltage difference is less than voltage difference threshold value, judge to meet between first battery system and second battery system Voltage uniformity.

14. devices according to claim 8, it is characterised in that first battery system and second battery system It is the battery system composed in parallel by more than two battery systems at most to have one in both.

A kind of 15. voltage balancing methods, are applied to first battery system and the second battery system of multiple branch circuit batteries in parallel connection system, Voltage of the voltage of first battery system more than second battery system, it is characterised in that including：

First battery system is charged to second battery system with constant current value by variable resistor, be designated as first Charging circuit；

Detect the resistance of the variable resistor；

If the resistance of the variable resistor is less than resistance value threshold value, first charging circuit is disconnected, make the first battery system System directly charges to second battery system, is designated as the second charging circuit, and detect the charging electricity of second charging circuit Stream；

Charging current according to detecting judges whether to stop charging.

16. methods according to claim 15, it is characterised in that the charging current according to detecting judges whether that stopping is filled The step of electricity, including：

If the charging current for detecting is more than current threshold, continue to make the first battery system pass through second charging circuit to institute State the charging of the second battery system；

Or, if the charging current for detecting is less than current threshold, stop charging second battery system.

17. methods according to claim 15, it is characterised in that also include：

If the resistance of the variable resistor is more than the resistance value threshold value, continue to make the first battery system be charged by described first Circuit charges to the second battery system.

18. methods according to claim 15, it is characterised in that first battery system and second battery system It is the battery system composed in parallel by more than two battery systems at most to have one in both.

Voltage balancing device between a kind of 19. battery systems, be applied to multiple branch circuit batteries in parallel connection system the first battery system and Second battery system, the voltage of the voltage more than second battery system of first battery system, it is characterised in that bag Include：

First charging module, for making first battery system pass through variable resistor with constant current value to second battery System charges, and is designated as the first charging circuit；

Resistance detection module, the resistance for detecting the variable resistor；

Second charging module, for when the resistance of the variable resistor is less than resistance value threshold value, disconnecting the first charging electricity Road, makes first battery system directly be charged to second battery system, is designated as the second charging circuit, and detects described the The charging current of two charging circuits；

Switch module, the charging current for being detected according to second charging module judges whether to stop charging.

20. devices according to claim 19, it is characterised in that the switch module is according to the charging current for detecting When judging whether to stop charging, specifically for：

If the charging current for detecting is more than current threshold, continue to make the first battery system pass through second charging circuit to institute State the charging of the second battery system；

Or, if the charging current for detecting is less than current threshold, stop charging second battery system.

21. devices according to claim 19, it is characterised in that also include：

Second switch module, for when the resistance of the variable resistor is more than the resistance value threshold value, continuing to make the first battery System is charged by first charging circuit to the second battery system.

22. devices according to claim 19, it is characterised in that first battery system and second battery system It is the battery system composed in parallel by more than two battery systems at most to have one in both.

A kind of detection of 23. battery systems and equalizing system, it is characterised in that the system includes voltage consistency detection device Voltage balancing device and between battery system,

The voltage consistency detection device is any one the voltage consistency detection device in claim 8 to 14,

Voltage balancing device between the battery system is that the voltage between any one battery system in claim 19 to 22 is equal Weighing apparatus device.

A kind of detection of 24. battery systems and equalizing circuit, it is characterised in that the circuit include first switch, second switch, Variable resistor, controller, voltage detection device, current detecting equipment, anode interface, negative pole interface, the voltage detection device Two ends be connected with the anode interface and the negative pole interface respectively, the current detecting equipment is connected with the second switch Between the anode interface and the negative pole interface, series circuit and institute that the first switch is constituted with the variable resistor State second switch in parallel, the first switch, the second switch, the variable resistor, the voltage detection device, the electricity Flow assay device controller is connected by low-voltage transmission line with the controller respectively, and the low-voltage transmission line is removed in the circuit Other outer connecting lines are hv transmission line.

25. circuits according to claim 24, it is characterised in that the variable resistor is program control load.