CN110707374A

CN110707374A - Parallel battery management system and method

Info

Publication number: CN110707374A
Application number: CN201810749826.6A
Authority: CN
Inventors: 李成泰; 陈韦匡
Original assignee: Celxpert Energy Corp
Current assignee: Celxpert Energy Corp
Priority date: 2018-07-10
Filing date: 2018-07-10
Publication date: 2020-01-17
Anticipated expiration: 2038-07-10
Also published as: CN110707374B

Abstract

The invention discloses a parallel battery management system and a method. The system comprises a plurality of battery blocks and a communication bus which are connected in parallel. The battery blocks respectively comprise a switch assembly, a battery module and a management module. The management module comprises a processor and a detection module. The detection module is used for detecting the electrical information of the battery module and the on-off state of the switch assembly. The processor is configured to execute a management program, and the management program comprises the steps of converting current circuit layout data into thevenin equivalent circuit data based on thevenin theorem, calculating the charging and discharging current value of the battery module after the switch assembly is switched to the conducting state based on the equivalent voltage value, the equivalent resistance value and the electrical property information, judging whether the corresponding switch assembly can be switched to the conducting state according to the preset current threshold value and the charging and discharging current value, and generating a judgment result, so that the parallel connection time point of the battery modules can be accurately and properly controlled.

Description

Parallel battery management system and method

Technical Field

The invention relates to a parallel battery management system and a method, in particular to a parallel battery management system and a method for managing batteries based on thevenin theorem.

Background

Power batteries are rapidly evolving, but battery weight and safety issues, which make transportation problems, are very limited.

If the small-power battery modules can be combined into a required large-power battery module according to the application, and ideal parallel management is added, the transportation problem can be relieved, and various market requirements can be met.

However, in the conventional parallel battery module, when a plurality of battery modules are connected in parallel, current flows from the battery module with higher voltage to the battery module with lower voltage according to electrical characteristics, and if the voltage difference between the plurality of battery modules is too large, not only an excessive current is generated, but also sparks are generated, and if the voltage difference is too large, the components are damaged, and if the voltage difference is too large, the components are exploded, so that a management mechanism is urgently needed to control the time point of parallel connection of the plurality of battery modules.

Therefore, how to accurately and properly control the time point of parallel connection of battery modules by improving the management mechanism to overcome the above-mentioned drawbacks has become one of the important issues to be solved by the above-mentioned industry.

Disclosure of Invention

The present invention provides a parallel battery management system for overcoming the disadvantages of the prior art, which includes a plurality of battery blocks connected in parallel with each other and a communication bus connected in parallel with each other, wherein each of the plurality of battery blocks includes a switch assembly, a battery module and a management module. The switch component is arranged between the first node and the second node and is configured to be switched between a conducting state and a switching-off state. The battery module is connected between the switch component and the second node. The management module is respectively connected with the switch assembly and the battery module and comprises a processor and a detection module. The detection module is used for detecting the electrical information of the battery module and the on-off state of the switch assembly. A communication bus respectively connected to the management modules of the battery blocks, wherein each processor is configured to execute a management program, the management program comprising: acquiring the switch state of each switch assembly and the electrical information of each battery module through the communication bus; generating current circuit layout data according to the switch states and the electrical information; converting the current circuit layout data into Davining equivalent circuit data based on Davining theorem, wherein the Davining equivalent circuit data defines a Davining equivalent circuit, the Davining equivalent circuit has a first port and a second port which present an open circuit state, the first port corresponds to the first node, the second port corresponds to the second node, and the Davining equivalent circuit comprises an equivalent voltage source and an equivalent resistance; calculating an equivalent voltage value of the equivalent voltage source and an equivalent resistance value of the equivalent resistor according to the current circuit layout data and the thevenin equivalent circuit data; calculating the charging and discharging current value of the battery module after the switch assembly is switched to the conducting state based on the equivalent voltage value, the equivalent resistance value and the electrical information; judging whether the corresponding switch component can be switched into a conducting state or not according to a preset current threshold value and the charging and discharging current value, and generating a judgment result; and controlling the switch state of the corresponding switch component according to the judgment result.

Preferably, each of the battery modules includes a battery source and a battery internal resistance, each of the electrical information includes an open-circuit voltage value and a battery internal resistance value of the battery source, and the processor is configured to generate the current circuit layout data according to the switch states, the open-circuit voltage values and the battery internal resistance values.

Preferably, the management program further includes calculating the equivalent resistance value of the equivalent resistance according to the battery internal resistance values.

Preferably, the management program further includes calculating the equivalent voltage value of the equivalent voltage source according to the switch states, the open-circuit voltage values and the battery internal resistance values.

Preferably, each of the processors is configured to determine in advance whether the switch state of the corresponding switch assembly is an off state before executing the management program, and if so, execute the management program.

Preferably, the hypervisor includes: converting the current circuit layout data into a norton equivalent circuit data based on norton's theorem, wherein the norton equivalent circuit data defines a norton equivalent circuit having a first port and a second port exhibiting an open state, the first port corresponding to the first node and the second port corresponding to the second node, and the norton equivalent circuit includes an equivalent current source and an equivalent resistor; calculating an equivalent current value of the equivalent current source and an equivalent resistance value of the equivalent resistor according to the current circuit layout data and the Norton equivalent circuit data; calculating a charging and discharging current value of the battery module after the switch assembly is switched to the conducting state based on the equivalent voltage value, the equivalent resistance value and the electrical information; judging whether the corresponding switch assembly can be switched into a conducting state according to a preset current threshold value and the charging and discharging current value, and generating a judgment result; and controlling the switch state of the corresponding switch component according to the judgment result.

In order to solve the above technical problem, one of the technical solutions adopted by the present invention is to provide a parallel battery management method, which includes: a plurality of battery blocks are connected in parallel with each other, and each battery block comprises a switch assembly, a battery module and a management module. The switch component is arranged between the first node and the second node and is configured to be switched between a conducting state and a switching-off state. The battery module is connected between the switch component and the second node. The management module is respectively connected with the switch assembly and the battery module and comprises a processor and a detection module. The detection module is used for detecting the electrical information of the battery module and the on-off state of the switch assembly. Furthermore, the management modules of the battery blocks are respectively connected through communication buses; each processor is configured to execute a hypervisor comprising: acquiring the switch state of each switch assembly and the electrical information of each battery module through a communication bus; generating current circuit layout data according to the switch states and the electrical information; converting the current circuit layout data into thevenin equivalent circuit data based on thevenin theorem, wherein the thevenin equivalent circuit data defines a thevenin equivalent circuit, the thevenin equivalent circuit is provided with a first port and a second port which present an open circuit state, the first port corresponds to a first node, the second port corresponds to a second node, and the thevenin equivalent circuit comprises an equivalent voltage source and an equivalent resistance; calculating an equivalent voltage value of an equivalent voltage source and an equivalent resistance value of an equivalent resistor according to the current circuit layout data and the Davining equivalent circuit data; calculating the charging and discharging current value of the battery module after the switch assembly is switched to the conducting state based on the equivalent voltage value, the equivalent resistance value and the electrical property information; judging whether the corresponding switch assembly can be switched into a conducting state according to the preset current threshold value and the charging and discharging current value, and generating a judgment result; and controlling the on-off state of the corresponding switch component according to the judgment result.

Preferably, each of the battery modules includes a battery source and a battery internal resistance, each of the electrical information includes an open-circuit voltage value and a battery internal resistance value of the battery source, and the management program further configures the processor to generate the current circuit layout data according to the switch states, the open-circuit voltage values and the battery internal resistance values.

Preferably, the parallel battery management method further includes: and configuring each processor to judge whether the switch state of the corresponding switch assembly is an off state in advance before executing the management program, and if so, configuring each processor to execute the management program.

The parallel battery management system and the parallel battery management method have the advantages that the technical scheme of converting current circuit layout data into thevenin equivalent circuit data based on thevenin theorem and calculating the charging and discharging current values of the battery modules after the switch assemblies are switched to the conducting state based on the equivalent voltage value, the equivalent resistance value and the electrical property information can be adopted, so that whether the corresponding switch assemblies can be switched to the conducting state or not can be judged according to the preset current threshold value and the charging and discharging current values, the parallel time point of the battery modules can be accurately and properly controlled, and the defects in the prior art can be overcome.

For a better understanding of the features and technical content of the present invention, reference should be made to the following detailed description of the invention and accompanying drawings, which are provided for purposes of illustration and description only and are not intended to limit the invention.

Drawings

Fig. 1 is a block diagram of a parallel battery management system according to a first embodiment of the present invention.

Fig. 2 is an enlarged view of a battery block a of the parallel battery management system according to the first embodiment of the present invention.

Fig. 3 is a flowchart of a management procedure of a parallel battery management system according to a second embodiment of the present invention.

Fig. 4 is a circuit layout diagram illustrating an exemplary operation of a parallel battery management system according to a third embodiment of the present invention.

FIG. 5 is a Davining equivalent circuit diagram after the circuit layout diagram according to the third embodiment of the present invention is equivalent.

Fig. 6 is a circuit diagram of a davinin equivalent circuit after the switching element 12D is turned on according to the third embodiment of the present invention.

Fig. 7 is a circuit layout diagram illustrating another exemplary operation of the parallel battery management system according to the third embodiment of the present invention.

FIG. 8 is a Davining equivalent circuit diagram after the equivalent of another circuit layout diagram according to the third embodiment of the present invention.

Fig. 9 is a circuit diagram of a davinin equivalent circuit after the switching element 12C is turned on according to the third embodiment of the present invention.

Fig. 10 is a flowchart of a parallel battery management method according to a fourth embodiment of the present invention.

Detailed Description

The following is a description of the embodiments of the parallel battery management system and method disclosed in the present invention with reference to specific embodiments, and those skilled in the art will understand the advantages and effects of the present invention from the disclosure of the present specification. The invention is capable of other and different embodiments and its several details are capable of modification and various other changes, which can be made in various details within the specification and without departing from the spirit and scope of the invention. The drawings of the present invention are for illustrative purposes only and are not intended to be drawn to scale. The following embodiments will further explain the related technical matters of the present invention in detail, but the disclosure is not intended to limit the scope of the present invention.

It will be understood that, although the terms first, second, third, etc. may be used herein to describe various components or signals, these components or signals should not be limited by these terms. These terms are used primarily to distinguish one element from another element or from one signal to another signal. In addition, as used herein, the term "or" should be taken to include any one or combination of more of the associated listed items as the case may be.

For clarity of explanation, in some cases the technology may be presented as including individual functional blocks comprising functional blocks, which comprise steps or routes in methods implemented in devices, device components, software, or a combination of hardware and software.

Apparatus embodying methods in accordance with the present disclosure may include hardware, firmware, and/or software and may take any of a variety of forms. Typical examples of such features include large energy storage systems, electric vehicles, and other high current devices. The functionality described herein may also be implemented in a peripheral device or in an embedded card. By way of further example, such functionality may also be implemented on different chips or on a circuit board executing different programs on a single device.

The instructions, media for conveying such instructions, computing resources for executing the same, or other structures for supporting such computing resources are means for providing the functionality described in these publications.

First embodiment

Referring to fig. 1, fig. 1 is a block diagram illustrating a parallel battery management system according to a first embodiment of the present invention. As shown, the parallel battery management system 1 includes a plurality of battery blocks A, B, …, N connected in parallel with each other and a communication bus 13, and the battery blocks A, B, …, N respectively include

switch assemblies

12A, 12B, …, 12N,

battery modules

10A, 10B, …, 10N and

management modules

14A, 14B, …, 14N. The

battery modules

10A, 10B, …, 10N are connected in series with the

switch assemblies

12A, 12B, …, 12N, respectively.

Fig. 2 is an enlarged view of a battery block a of the parallel battery management system according to the first embodiment of the present invention. For the battery block a, the battery block a includes a switch assembly 12A, a battery module 10A and a management module 14A. The switch element 12A is disposed between the first node N1A and the battery module 10A, and is configured to switch between an on state and an off state. The battery module 10A is connected to the switch assembly 12A, the management module 14A, and the second node N2A.

Referring to fig. 1 and 2, the

battery modules

10A, 10B, …, 10N can properly manage the operation of the

modules

14A, 14B, …, 14N to maintain proper voltage distribution among the parallel battery blocks A, B, …, N. In one or more embodiments of the present invention, the battery blocks A, B, …, N may be battery packs, respectively, and the

battery modules

10A, 10B, …, 10N may be battery cells, respectively, and the number of series/parallel connections may be adjusted according to requirements. The

switch assemblies

12A, 12B, …, 12N are operated to properly manage the flow of current between the

battery modules

10A, 10B, …, 10N, and can be charged and discharged with proper electronic characteristics. Each of the

battery modules

10A, 10B, …, and 10N may include a plurality of battery cells, and each of the plurality of battery cells may be a secondary battery such as a lithium ion battery or a lead battery.

In the embodiment, the management module 14A is connected to the switch assembly 12A and the battery module 10A, respectively, and the management module 14A includes a processor 140 and a detection module 142.

The detecting module 142 can be used for detecting electrical information of the battery module 10A, such as open-circuit voltage (OCV), and respectively generating electrical information signals, and the processor 140 can be configured to process the electrical information signals to obtain the open-circuit voltage of the battery module 10A. On the other hand, the detecting module 142 can also be used for detecting the switch state of the switch element 12A, and the switch state of the switch element 12A can be controlled by the processor 140. The detection module 142 may be an Analog Front End (AFE) circuit, such as a pure analog circuit or a digital-analog hybrid circuit, and may perform signal capture (signal capture), analog filtering (analog filtering), digital-analog conversion (DAC), analog-digital conversion (ADC), power amplification, and other functions.

It should be noted that the detection module 142 may be subordinate to the processor 140, and the processor 140 may be implemented by using one or more processors. The processor 140 may be a programmable unit such as a microprocessor, a microcontroller, a Digital Signal Processor (DSP) chip, a field-programmable gate array (FPGA), or the like. The functions of the processor 140 may also be implemented by one or several electronic devices or ICs. In other words, the functions performed by the processor 140 may be implemented by hardware, software, or a combination of hardware and software.

In particular, the parallel battery management system 1 further includes a communication bus 13, which is connected to the

management modules

14A, 14B, …, 14N of the battery blocks A, B, …, N, respectively. Thus, the acquired electrical information of the

battery modules

10A, 10B, …, 10N and the switching states of the

switch assemblies

12A, 12B, …, 12N may be transmitted to the

management modules

14A, 14B, …, 14N through the communication bus 13.

Wherein each processor, such as processor 140, may be configured to execute a hypervisor. In detail, the management program determines whether the corresponding switch element, for example, the switch element 12A, can be switched to the on state and whether the corresponding switch element, for example, the switch element 12A, may have an adverse effect on other battery modules after being switched to the on state, based on the davinin theorem mainly according to the current electrical information of the

battery modules

10A, 10B, …, 10N and the switch states of the

switch elements

12A, 12B, …, 12N. Therefore, the management mechanism can calculate the accurate and proper time for switching the switch assembly of the corresponding battery block, and simultaneously ensure that the battery block which is charged and discharged can still maintain normal operation.

Second embodiment

Please refer to fig. 2 and fig. 3, which are flowcharts of a management procedure of a parallel battery management system according to a second embodiment of the present invention. As shown, the hypervisor includes the following steps:

step S100: the switching states of the

switching elements

12A, 12B, …, 12N and the electrical information of the

battery modules

10A, 10B, …, 10N are obtained through the communication bus 13. Each

battery module

10A, 10B, …, 10N may include a battery source and an internal battery resistance, and thus the electrical information may include an open circuit voltage value of the battery source and an internal battery resistance value.

Step S102: and generating current circuit layout data according to the switch states and the electrical information. In addition, the processor 140 may be further configured to generate current circuit layout data according to the switch states, the open-circuit voltage values, and the battery internal resistance values. The current circuit layout data includes all electrical information of the parallel battery management system 1, i.e., the open circuit voltage value and the battery internal resistance value of the battery source in each

battery module

10A, 10B, …, 10N, and can be stored in the form of digital data in the memory cells (not shown) built in the

management modules

14A, 14B, …, 14N.

Step S104: and converting the current circuit layout data into thevenin equivalent circuit data based on thevenin theorem. The Thevenin's theorem, also known as the law of equivalent voltage sources, states that a circuit with a voltage source and a resistance can be converted into a Thevenin equivalent circuit comprising an ideal voltage source connected in series with an ideal resistance. The circuit architecture of the present embodiment can process the current circuit layout data through the processor 140 based on the above theorem, so as to generate the davinin equivalent circuit data.

The Davining equivalent circuit data defines a Davining equivalent circuit, the Davining equivalent circuit has a first port and a second port which are open-circuit, the first port corresponds to a first node, the second port corresponds to a second node, and the Davining equivalent circuit comprises an equivalent voltage source and an equivalent resistance. For the battery block a, if the effect generated after the switch assembly 12A is switched to the on state is determined, the switch assembly 12A and the battery module 10A may be temporarily removed, and the first node N1A and the second node N2A are respectively used as the first port and the second port of the davining equivalent circuit, in which case, the battery sources and the internal resistances included in the battery modules 10B, …, 10N in the on state of the switch assemblies 12B, …, 12N are equivalent to the equivalent voltage source and the equivalent resistance in the davining equivalent circuit.

Step S106: and calculating an equivalent voltage value of an equivalent voltage source and an equivalent resistance value of an equivalent resistor according to the current circuit layout data and the thevenin equivalent circuit data. Specifically, the output voltage between the first port and the second port can be calculated under the condition that the two ends of the first port and the second port are open (without any external current output, namely when the impedance between the first port and the second port is infinite), and the output voltage is the equivalent voltage value. Calculating the output current between the first port and the second port under the condition that the first port and the second port are short-circuited (i.e. the load resistance is zero), wherein the equivalent resistance value is equal to the equivalent voltage value divided by the output current.

Step S108: and calculating a charging and discharging current value of the battery module after the switch assembly is switched to the conducting state based on the equivalent voltage value, the equivalent resistance value and the electrical information.

Step S110: and judging whether the corresponding switch assembly can be switched into a conducting state or not according to a preset current threshold value and the charging and discharging current value. In other words, the predetermined current threshold may be a current allowable range of the

battery modules

10A, 10B, …, 10N. If the calculated charge/discharge current value is within the current allowable range of the

battery modules

10A, 10B, …, 10N, it is determined that the switching element, for example, the switching element 12A, can be switched to the on state without adverse effects. On the other hand, if the calculated charge/discharge current value exceeds the current allowable range of the

battery modules

10A, 10B, …, and 10N, it is determined that the switching element, for example, the switching element 12A, should not be switched to the on state at this time.

If yes, the process proceeds to step S112: and switching the corresponding switch component into a conducting state according to the judgment result. For the battery block a, if the calculated charging/discharging current value is within the current allowable range of the battery module 10A, the processor 140 may switch the switch assembly 12A to the on state according to the determination result.

If not, the process proceeds to step S114: and maintaining the corresponding switch component in the off state according to the judgment result. For the battery block a, if the calculated charging/discharging current value exceeds the current allowable range of the battery module 10A, the processor 140 may maintain the switch assembly 12A in the off state according to the determination result.

Similarly, in step S104, the current circuit layout data can also be converted into the one-notton equivalent circuit data based on the norton theorem. Norton's theorem states that a circuit having a voltage source and a resistance can be converted into a Norton equivalent circuit that includes an ideal current source in parallel with an ideal resistance. The data of the Norton equivalent circuit defines a Norton equivalent circuit which is provided with a first port and a second port presenting an open circuit state. The first port corresponds to a first node, the second port corresponds to a second node, and the Norton equivalent circuit includes an equivalent current source and an equivalent resistor. For the battery block a, if the effect generated after the switch component 12A is switched to the on state is determined, the switch component 12A and the battery module 10A can be temporarily removed, and the first node N1A and the second node N2A are respectively used as the first port and the second port of the norton equivalent circuit, in this case, the battery sources and the internal resistances included in the battery modules 10B, …, 10N in the on state in the switch components 12B, …, 12N are equivalent to the equivalent current source and the equivalent resistance in the norton equivalent circuit.

Therefore, the equivalent current value of the equivalent current source and the equivalent resistance value of the equivalent resistor can be calculated subsequently according to the current circuit layout data and the Noton equivalent circuit data. Specifically, the output current between the first port and the second port can be calculated under the condition that the two ends of the first port and the second port are short-circuited (i.e. the load resistance is zero), and the output current is the equivalent current value. The output voltage between the first port and the second port is calculated under the condition that the first port and the second port are open (without any outgoing current output, i.e. when the impedance between the first port and the second port is infinite), and the equivalent resistance value is equal to the output voltage value divided by the equivalent current value.

Similarly, in step S108, a charging/discharging current value of the battery module after the switch element is switched to the on state can be calculated based on the equivalent current value, the equivalent resistance value and the electrical information. The Davining equivalent circuit and the Noton equivalent circuit can be interchanged according to the relational expressions of Rth, Rno, Vth, Rno and Vth/Rth, Ino, wherein Rth, Rno, Vth and Ino respectively represent Davining equivalent resistance, Noton equivalent resistance, Davining equivalent independent voltage source and Noton independent current source.

According to the parallel battery management system provided by the invention, the technical scheme of converting the current circuit layout data into thevenin equivalent circuit data based on thevenin theorem and calculating the charging and discharging current values of the battery modules after the switch assemblies are switched to the conducting state based on the equivalent voltage value, the equivalent resistance value and the electrical property information is adopted, so that whether the corresponding switch assemblies can be switched to the conducting state or not is judged according to the preset current threshold value and the charging and discharging current values, the parallel time point of the battery modules can be accurately and properly controlled, and the defects in the prior art are overcome.

Third embodiment

Referring to fig. 4 and 5, an exemplary operation of the parallel battery management system of the present invention will be described. Fig. 4 is a circuit layout diagram illustrating an exemplary operation of a parallel battery management system according to a third embodiment of the present invention, and fig. 5 is a circuit diagram illustrating an equivalent circuit of thevenin after the circuit layout diagram is equivalent according to the third embodiment of the present invention.

As shown in fig. 4, a simplified circuit diagram of the parallel battery management system 2 is provided. Parallel battery management system 2 includes battery blocks A, B, C, D, and each includes

switch assemblies

12A, 12B, 12C, and 12D and

battery modules

10A, 10B, 10C, and 10D. In this situation, the

switch assemblies

12A, 12B, 12C are already in the on state, the switch assembly 12D is not yet turned on, and the

battery modules

10A, 10B, 10C, and 10D each include internal resistors R1, R2, R3, R4, and battery sources S1, S2, S3, S4, wherein the internal resistors R1, R2, R3, R4 have the same resistance value, which is 20m Ω, and the open circuit voltage values of the battery sources S1, S2, S3, S4 are V1, V2, V3, V4, which are 4V, 3.8V, 3.6V, and 4.2V, respectively.

In the simplified circuit architecture of the parallel battery management system 2, the resistance values of the internal resistors R1, R2, R3 and R4 and the open-circuit voltage values of the battery sources S1, S2, S3 and S4 can be stored as the current circuit layout data.

At this time, as shown in fig. 5, in order to determine the effect of the switch assembly 12D on the system, from the view of the battery block D, the first node N1D and the second node N2D are used as the first port a0 and the second port B0 of the davining equivalent circuit to obtain the davining equivalent circuit with two points of the first port a0 and the second port B0, wherein the davining equivalent circuit includes an equivalent voltage source Vth and an equivalent resistance Rth connected in series with the Vth.

On the other hand, from the viewpoint of the battery block D, the first node N1D and the second node N2D may be used as the first port a0 and the second port B0 in the norton equivalent circuit to obtain the norton equivalent circuit of two points of the first port a0 and the second port B0. The norton equivalent circuit includes an equivalent current source Ith and an equivalent resistor Rno connected in parallel.

For convenience of description, the davinin equivalent circuit will be described below, and the norton equivalent circuit can be converted according to the above relation, so that the description thereof is omitted. First, the voltage across the two points of the first port a0 and the second port B0 is obtained, and the current I1 shown in the figure can be obtained by the following formula (1) by using the overlapping theorem and the short-circuit characteristic of the voltage source:

therefore, according to the voltage division theorem, the current I12 is 66.7A, and the current I13 is 66.7A. The current I2 shown in the figure can be obtained from the following formula (2).

According to the principle of voltage division, the current I23 is 63.3A, and the current I21 is 63.3A. The current I3 shown in the figure can be obtained from the following equation (3).

According to the principle of voltage division, the current I31 is 60A, and the current I32 is 60A.

Therefore, from the above data, the voltage steps VR1, VR2 and VR3 of the internal resistances R1, R2 and R3 can be further determined by the following formulas (4), (5) and (6):

VR1 ═ (I1-I21-I31) ═ 20m Ω ═ 0.2V … … …, formula (4)

VR2 ═ (I2-I12-I32) × 20m Ω ═ 0 … … … formula (5)

VR3 ═ 20m Ω ═ -0.2V … … … (I3-I13-I23), formula (6)

The resistance of the equivalent resistor Rth and the voltage Vth of the equivalent voltage source in the Thevenin equivalent circuit can be further obtained by the following formulas (7) and (8):

rth R1// R2// R3 6.66m omega … … …, formula (7)

Vth 3.8V … … … formula (8)

Therefore, it can be assumed that the equivalent circuit formed after the switch element 12D is turned on is as shown in fig. 6, and fig. 6 is a davinin equivalent circuit diagram after the switch element 12D is turned on according to the third embodiment of the present invention. In the battery block D, the open circuit voltage value V4 of the battery source of the battery module 10D is 4.2. Therefore, the equivalent current value Ith and the current I4 of the thevenin equivalent circuit can be obtained by the superposition theorem according to the following equations (9) and (10):

ith Vth/(Rth + R4) ═ 142.5a … … … formula (9)

I4 ═ V4/(Rth + R4) ═ 157.5a … … …, formula (10)

Therefore, the current I0 ═ Ith-I4 ═ 15A flowing through the first node N1D and the second node N2D can be obtained. Since it is negative, the current I0 is the discharge current IDSG according to the definition of the current direction. Therefore, it can be seen that if the switch element 12D is switched to the on state, the battery block D will receive the discharge current of 15A.

In another example, if the open-circuit voltage V4 of the battery source of the battery module 10D is 3.4, the equivalent current values Ith, I4 and I0' of the davining equivalent circuit can be obtained by the overlapping theorem and equations (9), (11) and (12).

I4 ═ V4/(Rth + R4) ═ 127a … … … formula (11)

I0' ═ Ith-I4 ═ 15.5a … … … formula (12)

Since the current is positive, the current I0' is the charging current ICHG by definition of the current direction. Therefore, it can be known that if the switch element 12D is switched to the on state, the battery block D will receive the charging current of 15.5A.

After calculating the currents I0 and I0', the processor is further configured to determine whether the following equation (13) is satisfied:

IDSGMAX < I0 (I0') < ICHGMAX … … … equation (13)

If I0 and I0' are determined to be within the range, the processor determines that the switch assembly 12D is switched to the ready-to-conduct state, and the current range that the battery block D can bear will not be exceeded. After the condition of the battery block D is determined, the charging/discharging current value of the battery module A, B, C is calculated in a similar manner according to the calculation result, and if the charging/discharging current values of the battery module A, B, C are all determined to be the current allowable value, the calculation result of the charging/discharging current value of the battery module A, B, C, D is integrated to determine whether to control the switching of the switch assembly 12D to the on state.

It should be understood that, according to the norton equivalent circuit and the overlap theorem, it can also be determined whether the current range that the battery block D can bear when the switch assembly 12D is switched to the on state exceeds the current range that the battery block D can bear, and the charging and discharging current values of the battery module A, B, C after the switch assembly 12D is switched to the on state are further calculated in a similar manner, and if the charging and discharging current values of the battery module A, B, C, D are all determined to be the current allowable values, the configuration management module 14D controls the switch assembly 12D to be switched to the on state.

The calculation of the battery module C will be further explained below. Please refer to fig. 7 and 8 for an exemplary operation of the parallel battery management system of the present invention. Fig. 7 is a circuit layout diagram of another exemplary operation of the parallel battery management system according to the third embodiment of the present invention, and fig. 8 is a circuit diagram of an equivalent circuit of thevenin after the equivalent of another circuit layout diagram according to the third embodiment of the present invention.

Continuing with fig. 4, fig. 7 provides a simplified circuit diagram of the parallel battery management system 3. In this situation, it is assumed that the

switch assemblies

12A, 12B, 12D are already in the on state, and it is necessary to determine whether the switch assembly 12C is turned on, and the

battery modules

10A, 10B, 10C, and 10D each include internal resistors R1, R2, R3, R4, and battery sources S1, S2, S3, S4, wherein the internal resistors R1, R2, R3, and R4 have the same resistance value, which is 20m Ω, and the open-circuit voltages of the battery sources S1, S2, S3, and S4 are V1, V2, V3, and V4, which are 4V, 3.8V, 3.6V, and 4.2V, respectively.

The simplified circuit structure of the parallel battery management system 3, the resistance values of the internal resistors R1, R2, R3, and R4, and the open-circuit voltage values of the battery sources S1, S2, S3, and S4 may be stored as the current circuit layout data.

At this time, in order to determine the effect of the switch element 12C on the system, the first node N1C and the second node N2C are used as the first port a0 'and the second port B0' of the davining equivalent circuit from the view point of the battery block C, so as to obtain the davining equivalent circuit with two points of the first port a0 'and the second port B0'.

First, the voltage across the two ports, i.e. the first port a0 'and the second port B0', is obtained, and the current I1 'can be obtained by the following equation (1)' by using the overlapping theorem and the short-circuit characteristic of the voltage source:

therefore, according to the voltage division theorem, the current I12 'is 66.7A, and the current I14' is 66.7A. The current I2 'shown in the figure can be obtained from the following equation (2)'.

According to the principle of voltage division, the current I24 'is 63.3A, and the current I21' is 63.3A. The current I4 'shown in the figure can be obtained from the following equation (3)'.

According to the principle of voltage division, the current I41 'is 70A, and the current I42' is 70A.

Therefore, from the above data, the overvoltage VR1 ', VR 2' and VR4 'of the internal resistances R1, R2 and R4 can be further determined from the following formulas (4)', (5) ', and (6)':

VR1 ' (I1 ' -I21 ' -I41 ') -20 m Ω ═ 0V … … … formula (4) '

VR2 ' (I2 ' -I12 ' -I42 ') -20 m Ω -0.2 … … … formula (5) '

VR4 ' (I4 ' -I14 ' -I24 ') -20 m Ω ═ 0.2V … … … formula (6) '

The resistance value of the equivalent resistance Rth 'and the voltage value Vth' of the equivalent voltage source in the thevenin equivalent circuit can be further determined by the following formulas (7) 'and (8)':

rth 'R1// R2// R4 6.66m omega … … … formula (7)'

(8) 'of formula 4V … … …'

Therefore, it can be assumed that the equivalent circuit formed after the switch element 12C is turned on is as shown in fig. 9, and fig. 9 is a davinin equivalent circuit diagram after the switch element 12C is turned on according to the third embodiment of the present invention. In the battery block C, the open circuit voltage value V3 of the battery source of the battery module 10C is 3.6V. Therefore, the equivalent current value Ith ' and the current I3 ″ of the thevenin equivalent circuit can be obtained by the superposition theorem according to the following equations (9) ', (10) ':

ith '/(Rth ' + R3) ═ 150a … … … · formula (9) '

I3 ' ═ V3/(Rth ' + R3) ═ 135a … … … formula (10) '

Therefore, the current I3 '"-Ith' -I3-15A flowing through the first node N1C and the second node N2C can be obtained. Since the current is positive, the current I3' "is the charging current ICHG by definition of the current direction. Therefore, it can be seen that if the switch element 12C is switched to the on state, the battery block C will receive the charging current of 15A.

After calculating the current I3 '″, the processor is further configured to determine whether the following equation (11)' is satisfied:

IDSGMAX < I3 '″ < ICHGMAX … … … formula (11)'

If it is determined that I3' ″ is within the range, the processor determines that the switch element 12C is switched to the on state, and the current range that can be borne by the battery block C will not be exceeded. After the condition of the battery block C is determined, the charging/discharging current value of the battery module A, B, D is calculated according to the calculation result, and the calculation result of the charging/discharging current value of the battery module A, B, C, D is integrated to determine whether to control the switching of the switch assembly 12C to the on state. It should be noted that the charging/discharging current values of the battery module A, B, C, D need to be calculated by the above-mentioned process, and the system can determine which switch combination the

switch assemblies

12A, 12B, 12C, 12D can operate.

It should be understood that it can also be determined by the norton equivalent circuit and the overlap theorem whether the current range that the battery block C can bear when the switch assembly 12C is switched to the conducting state exceeds, and further, after the switch assembly 12C is switched to the conducting state is calculated in a similar manner, the charging and discharging current value of the battery module A, B, D is integrated with the calculation result of the charging and discharging current value of the battery module A, B, C, D to determine whether to control the switch assembly 12C to be switched to the conducting state.

Fourth embodiment

One aspect of the parallel battery management method of the present invention will be described in detail below with reference to the accompanying drawings. In this embodiment, the parallel battery management method is applied to the first to third embodiments, but is not limited thereto, and the method provided by this embodiment may also be applied to any of the above-described embodiments in a manner or with various possibilities that can be conceived by a person having ordinary skill in the art.

Please refer to fig. 10, which is a flowchart illustrating a parallel battery management method according to a fourth embodiment of the present invention.

Step S200: a plurality of battery blocks are connected in parallel with each other. As shown in fig. 1, each of the battery blocks includes a switch assembly, a battery module and a management module. The switch component is arranged between the first node and the second node and is configured to be switched between a conducting state and a switching-off state. The battery module is connected between the switch component and the second node. And the management module is respectively connected with the switch assembly and the battery module and comprises a processor and a detection module. The detection module is used for detecting the electrical information of the battery module and the on-off state of the switch assembly.

Step S202: and the management modules of the battery blocks are respectively connected through the communication bus.

Step S204: each processor is configured to execute a hypervisor. Optionally, each processor may be configured to perform step S203 in advance before executing the management program: and judging whether the switch state of the corresponding switch assembly is an off state, and if so, configuring the processor to execute the management program. The hypervisor further comprises the steps of:

step S206: acquiring the switch state of each switch assembly and the electrical information of each battery module through the communication bus;

step S208: generating current circuit layout data according to the switch states and the electrical information;

step S210: and converting the current circuit layout data into thevenin equivalent circuit data based on thevenin theorem. The Davining equivalent circuit data defines a Davining equivalent circuit, the Davining equivalent circuit is provided with a first port and a second port which are in an open circuit state, the first port corresponds to the first node, the second port corresponds to the second node, and the Davining equivalent circuit comprises an equivalent voltage source and an equivalent resistance. Further, each battery module includes a battery source and a battery internal resistance, the electrical information includes an open circuit voltage value of the battery source and a battery internal resistance value, and in this step, the management program further includes a configuration processor for generating current circuit layout data according to the switch states, the open circuit voltage values and the battery internal resistance values.

Step S212: and calculating an equivalent voltage value of the equivalent voltage source and an equivalent resistance value of the equivalent resistance according to the current circuit layout data and the Davining equivalent circuit data. In detail, referring to the foregoing embodiments, the equivalent resistance of the equivalent resistor is calculated according to the internal resistance of the batteries.

Step S214: and calculating the charging and discharging current value of the battery module after the switch assembly is switched to the conducting state based on the equivalent voltage value, the equivalent resistance value and the electrical information.

Step S216: and judging whether the corresponding switch assembly can be switched into a conducting state or not according to a preset current threshold value and the charging and discharging current value. In other words, the predetermined current threshold may be a current allowable range of the

battery modules

If yes, go to step S218: the corresponding switch element is switched to the on state according to the determination result for the

battery modules

10A, 10B, …, 10N. For the battery block a, if the calculated charging/discharging current value is within the current allowable range of the battery module 10A, the processor 140 may switch the switch assembly 12A to the on state according to the determination result.

If not, the process proceeds to step S220: and maintaining the corresponding switch component in the off state according to the judgment result. For the battery block a, if the calculated charging/discharging current value exceeds the current allowable range of the battery module 10A, the processor 140 may maintain the switch assembly 12A in the off state according to the determination result.

Advantageous effects of the embodiments

One of the benefits of the parallel battery management system and method provided by the invention is that the technical scheme of converting the current circuit layout data into thevenin equivalent circuit data based on thevenin theorem and calculating the charging and discharging current values of the battery modules after the switch assemblies are switched to the conducting state based on the equivalent voltage value, the equivalent resistance value and the electrical property information is adopted to judge whether the corresponding switch assemblies can be switched to the conducting state according to the preset current threshold value and the charging and discharging current values, so that the parallel time point of the battery modules can be accurately and properly controlled, and the defects in the prior art are overcome.

The disclosure is only a preferred embodiment of the present invention, and is not intended to limit the scope of the claims, so that all equivalent technical changes made by using the contents of the specification and the drawings are included in the scope of the claims.

Claims

1. A parallel battery management system, comprising:

a plurality of battery blocks are connected in parallel with each other, each including:

a switch element disposed between a first node and a second node and configured to switch between an on state and an off state;

the battery module is connected between the switch assembly and the second node; and

a management module, connect respectively the switch module reaches the battery module, management module includes: the detection module is used for detecting electrical information of the battery module and a switch state of the switch assembly; and

a communication bus connected with the management modules of the battery blocks,

wherein each processor is configured to execute a hypervisor comprising:

acquiring the switch state of each switch assembly and the electrical information of each battery module through the communication bus; generating current circuit layout data according to the switch states and the electrical information; converting the current circuit layout data into thevenin equivalent circuit data based on thevenin theorem, wherein the thevenin equivalent circuit data defines a thevenin equivalent circuit, the thevenin equivalent circuit is provided with a first port and a second port which present an open circuit state, the first port corresponds to the first node, the second port corresponds to the second node, and the thevenin equivalent circuit comprises an equivalent voltage source and an equivalent resistor; calculating an equivalent voltage value of the equivalent voltage source and an equivalent resistance value of the equivalent resistance according to the current circuit layout data and the Davining equivalent circuit data; calculating a charging and discharging current value of the battery module after the switch assembly is switched to the conducting state based on the equivalent voltage value, the equivalent resistance value and the electrical information; judging whether the corresponding switch assembly can be switched into a conducting state according to a preset current threshold value and the charging and discharging current value, and generating a judgment result; and controlling the switch state of the corresponding switch component according to the judgment result.

2. The parallel battery management system of claim 1, wherein each battery module includes a battery source and an internal battery resistance, each electrical information includes an open-circuit voltage value and an internal battery resistance value of the battery source, and the processor is configured to generate the current circuit layout data according to the switch states, the open-circuit voltage values and the internal battery resistance values.

3. The system of claim 2, wherein the management program further comprises calculating the equivalent resistance of the equivalent resistor according to the internal resistance of the battery.

4. The system of claim 2, wherein the management program further comprises calculating the equivalent voltage value of the equivalent voltage source according to the switch states, the open-circuit voltage values and the battery internal resistance values.

5. The parallel battery management system of claim 1, wherein each processor is configured to determine in advance whether the switch state of the corresponding switch element is an off state before executing the management program, and if so, execute the management program.

6. The parallel battery management system of claim 1, wherein the management program comprises:

converting the current circuit layout data into a norton equivalent circuit data based on norton's theorem, wherein the norton equivalent circuit data defines a norton equivalent circuit having a first port and a second port exhibiting an open state, the first port corresponding to the first node and the second port corresponding to the second node, and the norton equivalent circuit includes an equivalent current source and an equivalent resistor; calculating an equivalent current value of the equivalent current source and an equivalent resistance value of the equivalent resistance according to the current circuit layout data and the Norton equivalent circuit data; calculating a charging and discharging current value of the battery module after the switch assembly is switched to the conducting state based on the equivalent voltage value, the equivalent resistance value and the electrical information; judging whether the corresponding switch assembly can be switched into a conducting state according to a preset current threshold value and the charging and discharging current value, and generating a judgment result; and controlling the switch state of the corresponding switch component according to the judgment result.

7. A parallel battery management method, comprising:

connecting a plurality of battery blocks in parallel, wherein each battery block comprises:

the management module is respectively connected with the switch assembly and the battery module and comprises a processor and a detection module, and the detection module is used for detecting electrical information of the battery module and a switch state of the switch assembly;

the management module of each battery block is connected through a communication bus;

configuring each of the processors to execute a hypervisor, the hypervisor comprising:

8. The method of claim 7, wherein each battery module includes a battery source and an internal battery resistance, each electrical information includes an open-circuit voltage value and an internal battery resistance value of the battery source, and the management program further configures the processor to generate the current circuit layout data according to the switch states, the open-circuit voltage values, and the internal battery resistance values.

9. The method of claim 8, wherein the management program further comprises calculating the equivalent resistance of the equivalent resistor according to the internal resistance of the battery.

10. The method of claim 8, wherein the management procedure further comprises calculating the equivalent voltage value of the equivalent voltage source according to the switch states, the open-circuit voltage values and the battery internal resistance values.

11. The parallel battery management method of claim 7, further comprising:

and configuring each processor to judge whether the switch state of the corresponding switch assembly is an off state in advance before executing the management program, and if so, configuring each processor to execute the management program.

12. The parallel battery management method of claim 7, wherein the management program comprises: