CN113972724A

CN113972724A - Detection circuit and method, communication device and method, and battery equalization control method

Info

Publication number: CN113972724A
Application number: CN202111301153.6A
Authority: CN
Inventors: 不公告发明人
Original assignee: Zhuhai Maiju Microelectronics Co Ltd
Current assignee: Zhuhai Maiju Microelectronics Co Ltd
Priority date: 2020-11-26
Filing date: 2021-11-04
Publication date: 2022-01-25
Also published as: CN112398201A

Abstract

The utility model provides a battery voltage detection circuitry of series lithium battery system, including the N battery cell of establishing ties, wherein N is greater than or equal to 1, includes: the multiplexing module is connected to the N single batteries connected in series so as to receive a battery voltage signal of each of the N single batteries through the multiplexing module and select and output a battery voltage signal of one of the N single batteries at a time; a reference voltage generating unit for generating a varying reference voltage value; and a comparator for receiving the battery voltage signal output by the multiplexing module, receiving the changed reference voltage value, and comparing the received battery voltage signal and the reference voltage value a plurality of times according to the changed reference voltage value to output a measured voltage of one unit battery. The disclosure also provides a communication device and a detection method of the lithium battery system, a communication method of the lithium battery system and a battery balance control method of the lithium battery system.

Description

Detection circuit and method, communication device and method, and battery equalization control method

Technical Field

The present disclosure relates to a battery voltage detection circuit for a series lithium battery system, a communication device for a lithium battery system, a detection method for a battery voltage detection circuit for a series lithium battery system, a communication method for a lithium battery system, and a battery equalization control method for a lithium battery system.

Background

The lithium battery has high requirements for charging and discharging, and when overcharge, overdischarge, overcurrent, short circuit and the like occur, the internal pressure and heat of the lithium battery are greatly increased, and sparks, combustion and even explosion are easily generated, so that overcharge and overdischarge protection of the lithium battery pack is necessary.

In the pre-charging stage when the voltage of the lithium battery is low, a small charging current needs to be applied to protect the battery. Due to the inconsistency of the individual cells, it is required to take necessary equalization measures during charging to ensure the safety and stability thereof.

The currently common lithium battery pack equalization detection method is to compare the voltages of the single batteries, and if the voltage difference between the current single battery and any single battery exceeds a threshold value and the voltages of all the single batteries exceed an equalization starting voltage, the current battery needs to be equalized.

In the art, how to measure the voltage of the single battery is a key for accurately detecting whether the battery needs to be balanced.

Disclosure of Invention

In order to solve one of the above technical problems, the present disclosure provides a battery voltage detection circuit of a series lithium battery system, a communication device of the lithium battery system, a detection method of the battery voltage detection circuit of the series lithium battery system, a communication method of the lithium battery system, and a battery equalization control method of the lithium battery system.

According to an aspect of the present disclosure, a battery voltage detection circuit of a series lithium battery system, the series lithium battery system includes N single batteries connected in series, wherein N is greater than or equal to 1, including:

a multiplexing module connected to the N unit cells connected in series so as to receive a cell voltage signal of each of the N unit cells through the multiplexing module and select a cell voltage signal of one of the N unit cells at a time for output;

a reference voltage generation unit for generating a varying reference voltage value; and

a comparator for receiving the battery voltage signal output by the multiplexing module, receiving a varying reference voltage value, and comparing the received battery voltage signal and the reference voltage value a plurality of times according to the varying reference voltage value to output a measured voltage of the one unit battery,

the reference voltage value is changed within a preset range from a lowest equalization starting voltage to a highest battery voltage, and in the comparison process of the comparator, the reference voltage value is changed for each comparison in the process of measuring the battery voltage of each single battery, and the comparator compares the received battery voltage signal with the reference voltage value changed each time to output the measurement voltage of the battery voltage of each single battery.

According to at least one embodiment of the present disclosure, the variation of the reference voltage value within the preset range is: the reference voltage value is gradually increased within a preset range, or the reference voltage value is gradually decreased within a preset range.

According to at least one embodiment of the present disclosure, N-2 reference voltage points are preset within a preset range, wherein N-2 is a natural number; the reference voltage value is sequentially reduced and changed from the highest voltage, N-2 reference voltage points to the balance initial voltage; or the reference voltage values are sequentially increased and changed from the equilibrium initial voltage, the N-2 reference voltage values to the highest voltage.

According to at least one embodiment of the present disclosure, when the reference voltage value is one of the highest voltage, N-2 reference voltage points, and an equalization start voltage, setting an identification bit corresponding to a current reference voltage value to a first preset value; and when the battery voltage signal output by the multiplexing module is smaller than the current reference voltage value, setting the identification bit corresponding to the current reference voltage value as a second preset value.

According to at least one embodiment of the present disclosure, when the battery voltage signal output by the multiplexing module is greater than or equal to the current reference voltage value, the first preset value is used as the identification bit corresponding to the current reference voltage value.

According to at least one embodiment of the present disclosure, the voltage value of each unit cell is obtained according to the position where the identification bit is the first preset value.

According to at least one embodiment of the present disclosure, the reference voltage value is represented by M bits, when the reference voltage value is changed, the highest bit of the M bits is set to 1 and the remaining bits are set to 0 to obtain a first reference voltage value, the first reference voltage value is compared with the received battery voltage signal, if the battery voltage signal is less than the first reference voltage value, the output of the comparator is 0 and the highest bit is set to 0, and if the battery voltage signal is greater than the first reference voltage value, the output of the comparator is 1 and the highest bit is maintained unchanged.

According to at least one embodiment of the present disclosure, if the battery voltage signal is less than a first reference voltage value, in the case where the output of the comparator is 0 and the most significant bit is set to 0, continuing to set the next bit of the most significant bit to 0 and the remaining bits to 0 to obtain a second reference voltage value, comparing the second reference voltage value with the received battery voltage signal, if the battery voltage signal is less than a second reference voltage value, the output of the comparator is 0 and the next bit of the highest bits is set to 0, if the battery voltage signal is greater than a second reference voltage value, the output of the comparator is 1 and the next bit of the most significant bit is held constant, and continuing to perform the same operation on other bits if the battery voltage signal is less than a second reference voltage value.

According to at least one embodiment of the present disclosure, the reference voltage value is represented by M bits, when the reference voltage value is changed, the lowest bit of the M bits is set to 1 and the remaining bits are set to 0 to obtain a first reference voltage value, the first reference voltage value is compared with the received battery voltage signal, if the battery voltage signal is less than the first reference voltage value, the output of the comparator is 0 and the lowest bit is set to 0, and if the battery voltage signal is greater than the first reference voltage value, the output of the comparator is 1 and the lowest bit is maintained unchanged.

According to at least one embodiment of the present disclosure, if the battery voltage signal is less than a first reference voltage value, in the case where the output of the comparator is 0 and the lowest bit is set to 0, continuing to set the last bit of the lowest bit to 0 and the remaining bits to 0 to obtain a second reference voltage value, comparing the second reference voltage value with the received battery voltage signal, if the battery voltage signal is less than a second reference voltage value, the output of the comparator is 0 and the last bit of the lowest bits is set to 0, if the battery voltage signal is greater than a second reference voltage value, the output of the comparator is 1 and the last bit of the lowest bit is held constant, and continuing to perform the same operation on other bits if the battery voltage signal is less than a second reference voltage value.

According to at least one embodiment of the present disclosure, the battery voltage signal output by the multiplexing module is collected at least twice for the same reference voltage value, and the comparator compares the same reference voltage with the battery voltage signal output by the multiplexing module at least twice to obtain at least two comparison results, the at least two comparison results are input to the first filter, the first filter multiplies the at least two comparison results by corresponding weights to perform superposition, and the superposed signal is output.

According to at least one embodiment of the present disclosure, the first filter is an FIR filter, and for a same reference voltage value, the battery voltage signal output by the quadruple multiplexing module is collected, and the same reference voltage and the battery voltage signal output by the quadruple multiplexing module obtain four comparison results, and the FIR filter multiplies the four comparison results by corresponding weights and then superimposes the four comparison results, and takes the superimposed signal as output.

According to at least one embodiment of the present disclosure, when the output of the first filter is within the unreliable range, then the output of the first filter is taken as an unreliable measurement.

According to at least one embodiment of the present disclosure, the battery voltage correction device further includes a second filter that receives the battery voltage of each unit battery output from the first filter and corrects the battery voltage of each unit battery, and the corrected battery voltage of each unit battery is used as a final battery voltage of each unit battery.

According to at least one embodiment of the present disclosure, the second filter is a kalman filter.

According to at least one embodiment of the present disclosure, when measuring the battery voltage signal of each unit battery, the measurement is performed on each unit battery for a plurality of times to obtain a plurality of battery voltage signals, and an average value of the plurality of battery voltage signals is used as an initial state value of the kalman filter.

According to at least one embodiment of the present disclosure, after the battery voltages of all the unit batteries are obtained, the system minimum voltage values of the unit batteries in the series lithium battery system are obtained by comparing the battery voltages of the respective unit batteries.

According to at least one embodiment of the present disclosure, when the system minimum voltage value is higher than the battery equalization start voltage, it is determined whether a difference between a voltage value of a certain single battery in the series lithium battery system and the system minimum voltage value is greater than an equalization threshold voltage, and if the difference is greater than the equalization threshold voltage, the single battery is equalized.

According to another aspect of the present disclosure, a communication device of a lithium battery system includes: the battery voltage detection circuit of any one of the two or more claims 1 to 19,

the lithium battery system comprises a plurality of single batteries which are connected in series, each battery voltage detection circuit detects N single batteries in the plurality of single batteries which are connected in series, the lowest voltage value of each single battery in the N single batteries is obtained based on the measurement voltage output by each battery voltage detection circuit, the lowest voltage value of each single battery obtained by each battery voltage detection circuit is mutually transmitted and judged in each battery voltage detection circuit, and the lowest voltage value of each single battery in the system of the lithium battery system is obtained.

According to another aspect of the present disclosure, a method for detecting a battery voltage detection circuit of a series lithium battery system, the series lithium battery system including N single batteries connected in series, where N is greater than or equal to 1, includes:

the multiplexing module is connected to the N single batteries which are connected in series, so that a battery voltage signal of each single battery in the N single batteries is received through the multiplexing module, and a battery voltage signal of one single battery in the N single batteries is selected to be output at a time; and

a comparator receiving the battery voltage signal output by the multiplexing module and receiving a varying reference voltage value and comparing the received battery voltage signal and the reference voltage value a plurality of times according to the varying reference voltage value to output a measured voltage of the one unit battery,

According to at least one embodiment of the present disclosure, for a same reference voltage value, at least two times of battery voltage signals output by the multiplexing module are collected, and the comparator respectively compares the same reference voltage with the battery voltage signals output by the multiplexing module at least two times to obtain at least two comparison results, the at least two comparison results are input to the first filter, the first filter multiplies the at least two comparison results by corresponding weights to perform superposition, and the superposed signals are output.

According to at least one embodiment of the present disclosure, the second filter receives the battery voltage of each unit cell of the output of the first filter and corrects the battery voltage of each unit cell, and the corrected battery voltage of each unit cell is taken as the final battery voltage of each unit cell.

According to at least one embodiment of the present disclosure, after the battery voltages of all the unit batteries are obtained, the lowest voltage value of the unit batteries in the series lithium battery system is obtained by comparing the battery voltages of the respective unit batteries.

According to at least one embodiment of the present disclosure, when the lowest voltage value is higher than the battery equalization start voltage, it is determined whether a difference between a voltage value of a certain unit battery in the series lithium battery system and the lowest voltage value is greater than an equalization threshold voltage, and if the difference is greater than the equalization threshold voltage, the unit battery is equalized.

According to still another aspect of the present disclosure, a communication method of a lithium battery system including two or more battery voltage detection circuits as described above,

the lithium battery system comprises a plurality of single batteries which are connected in series, each battery voltage detection circuit detects N single batteries in the plurality of single batteries which are connected in series, the lowest voltage value of each single battery in the N single batteries is obtained based on the measurement voltage output by each battery voltage detection circuit, the lowest voltage value of each single battery obtained by each battery voltage detection circuit is mutually transmitted and judged in each battery voltage detection circuit, and the system lowest voltage value of each single battery of the lithium battery system is obtained.

According to another aspect of the disclosure, a battery equalization control method of a lithium battery system obtains the system minimum voltage value through the communication method, when the system minimum voltage value is higher than the battery equalization initial voltage, it is determined whether a difference between a voltage value of a certain single battery in a series lithium battery system and the system minimum voltage value is greater than an equalization threshold voltage, and if the difference is greater than the equalization threshold voltage, equalization processing is performed on the single battery.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the disclosure and together with the description serve to explain the principles of the disclosure.

Fig. 1 shows a schematic diagram of a series lithium battery stack system according to one embodiment of the present disclosure.

Fig. 2 shows a schematic diagram of a series lithium battery stack system according to one embodiment of the present disclosure.

Fig. 3 shows a schematic diagram of a communication frame according to an embodiment of the present disclosure.

Fig. 4 shows a schematic diagram of a sampling pattern according to an embodiment of the present disclosure.

Fig. 5 illustrates a flow chart of a communication method of a series lithium battery stack system according to one embodiment of the present disclosure.

Fig. 6 illustrates a schematic diagram of a battery voltage detection circuit of a series lithium battery system according to one embodiment of the present disclosure.

Fig. 7 shows a schematic diagram of a FIR filter according to one embodiment of the present disclosure.

FIG. 8 shows a schematic diagram of a Kalman filter according to one embodiment of the present disclosure.

Fig. 9 illustrates a flow chart of a detection method of a battery voltage detection circuit of a series lithium battery system according to one embodiment of the present disclosure.

Fig. 10 shows a schematic diagram of minimum voltage transmission according to one embodiment of the present disclosure.

Detailed Description

The present disclosure will be described in further detail with reference to the drawings and embodiments. It is to be understood that the specific embodiments described herein are for purposes of illustration only and are not to be construed as limitations of the present disclosure. It should be further noted that, for the convenience of description, only the portions relevant to the present disclosure are shown in the drawings.

It should be noted that the embodiments and features of the embodiments in the present disclosure may be combined with each other without conflict. Technical solutions of the present disclosure will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

Unless otherwise indicated, the illustrated exemplary embodiments/examples are to be understood as providing exemplary features of various details of some ways in which the technical concepts of the present disclosure may be practiced. Accordingly, unless otherwise indicated, features of the various embodiments may be additionally combined, separated, interchanged, and/or rearranged without departing from the technical concept of the present disclosure.

The use of cross-hatching and/or shading in the drawings is generally used to clarify the boundaries between adjacent components. As such, unless otherwise noted, the presence or absence of cross-hatching or shading does not convey or indicate any preference or requirement for a particular material, material property, size, proportion, commonality between the illustrated components and/or any other characteristic, attribute, property, etc., of a component. Further, in the drawings, the size and relative sizes of components may be exaggerated for clarity and/or descriptive purposes. While example embodiments may be practiced differently, the specific process sequence may be performed in a different order than that described. For example, two processes described consecutively may be performed substantially simultaneously or in reverse order to that described. In addition, like reference numerals denote like parts.

When an element is referred to as being "on" or "on," "connected to" or "coupled to" another element, it can be directly on, connected or coupled to the other element or intervening elements may be present. However, when an element is referred to as being "directly on," "directly connected to" or "directly coupled to" another element, there are no intervening elements present. For purposes of this disclosure, the term "connected" may refer to physically, electrically, etc., and may or may not have intermediate components.

For descriptive purposes, the present disclosure may use spatially relative terms such as "below … …," below … …, "" below … …, "" below, "" above … …, "" above, "" … …, "" higher, "and" side (e.g., as in "side wall") to describe one component's relationship to another (other) component as illustrated in the figures. Spatially relative terms are intended to encompass different orientations of the device in use, operation, and/or manufacture in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary term "below … …" can encompass both an orientation of "above" and "below". Further, the devices may be otherwise positioned (e.g., rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particular embodiments and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. Furthermore, when the terms "comprises" and/or "comprising" and variations thereof are used in this specification, the presence of stated features, integers, steps, operations, elements, components and/or groups thereof are stated but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groups thereof. It is also noted that, as used herein, the terms "substantially," "about," and other similar terms are used as approximate terms and not as degree terms, and as such, are used to interpret inherent deviations in measured values, calculated values, and/or provided values that would be recognized by one of ordinary skill in the art.

According to one aspect of the present disclosure, a communication device for a serial lithium battery stack system is provided.

Fig. 1 illustrates a communication device 10 for a series lithium battery stack system according to one embodiment of the present disclosure.

The series lithium battery stacking system is formed by connecting N-level series lithium battery units and a first-level lithium battery unit in series, wherein N is more than or equal to 1. As shown in fig. 1, the series lithium battery stack system includes a first-stage lithium battery cell 201, second-stage lithium battery cells 202 and … among N-stage series lithium battery cells, and an nth-stage lithium battery cell 20N. The first-stage lithium battery unit 201, the second-stage lithium battery units 202 and … and the nth-stage lithium battery unit 20n are sequentially connected in series to form a series lithium battery stacking system. Wherein the negative pole of the battery in the first stage lithium battery cell 201 constitutes the negative terminal and is grounded, and the positive pole of the battery of the nth stage lithium battery cell 20n constitutes the positive terminal and is the highest voltage VCC of the stacked system.

Each lithium battery unit in the N-level series lithium battery units may include one lithium battery or more than two lithium batteries. The first stage lithium battery cell may include one lithium battery cell or more than two lithium battery cells.

The positive and negative terminals of the series lithium battery stack system may be connected to an external charger or an external load. When the external charger is connected, the lithium batteries connected in series may be charged by the external charger, thereby performing a charging operation. When an external load is connected, the lithium batteries connected in series can supply electric power to the external load, thereby performing a discharging operation.

The communication device may include: the battery comprises a main battery chip 101 and N-level slave battery chips 102-10N, wherein N is larger than or equal to 1.

The main battery chip 101 is used to obtain the state information of the first-level lithium battery cell 201. Wherein the status information may include an event flag, a minimum voltage of the lithium battery cell, and the like.

The event flags may include flags for a charge protection state, a discharge protection state, and/or a precharge state.

Ports V + and V-of the main battery chip 101 may be connected to the positive and negative electrodes of the first-stage lithium battery cell 201, respectively. When the first-stage lithium battery cell 201 is a single battery, the voltage of the single battery can be obtained by the main battery chip 101. When the first-stage lithium battery unit 201 is a plurality of batteries connected in series, the main battery chip 101 can obtain the voltages of the plurality of batteries connected in series.

The N-th stage slave battery chips include a first stage slave battery chip 102 to an nth stage slave battery chip 10N.

The first slave battery chip 102 is used to acquire status information of the second lithium battery cell 202. Wherein the status information may include an event flag, a minimum voltage of the lithium battery cell, and the like.

Ports V + and V-of the first slave battery cell 102 may be connected to the positive and negative electrodes of the second lithium battery cell 202, respectively. When the second lithium secondary battery unit 202 is a single battery, the first secondary battery chip 102 can obtain the voltage of the single battery. When the second lithium secondary battery unit 202 is a plurality of batteries connected in series, the first stage slave battery chip 102 can obtain the voltage of the plurality of batteries connected in series.

The nth-stage slave battery chip 10N is used to acquire state information of the nth-stage lithium battery cell 20N. Wherein the status information may include an event flag, a minimum voltage of the lithium battery cell, and the like.

Ports V + (which may be the highest voltage VCC of the stacked system) and V-of the nth-stage slave battery chip 10N may be connected to the positive and negative electrodes of the nth-stage lithium battery cell 20N, respectively. When the nth-stage lithium battery cell 20N is a single battery, the nth-stage slave battery chip 10N can obtain the voltage of the single battery. When the nth stage lithium battery cell 20N is a plurality of batteries connected in series, the nth stage slave battery chip 10N can obtain the voltages of the plurality of batteries connected in series.

As can be known from the above description, the N-level slave battery chips are used for respectively acquiring the status information of the first lithium battery cells in the N-level series lithium battery cells. The state information of each stage of lithium battery unit is obtained from the battery chip at each stage, the state information of the lithium battery unit at the previous stage is transmitted to the slave battery chip at the current stage by the slave battery chip at the previous stage, and after the slave battery chip at the current stage is processed according to the state information of the lithium battery unit at the previous stage and the state information of the lithium battery unit at the current stage, the processing result is provided to the slave battery chip at the next stage. The next-level slave battery chip repeats the above operations, and finally provides the comprehensive state information of the N-level series lithium battery units to the master battery chip 101, and the master battery chip 101 processes the received processing result and the state information of the first-level lithium battery unit 201 obtained by the processing result to obtain the system state information of the N-level series lithium battery units and the first-level lithium battery unit, so that according to the system state information, the master battery chip 101 controls the discharge switch 300 and the charge switch 400 to control the charge or discharge of the series lithium battery stacking system.

Wherein the main battery chip 101 controls the turn-on and turn-off of the discharge switch 300 by a control signal DSG, and controls the turn-on and turn-off of the charge switch 400 by a control signal CHG. And the charge switch 300 and the discharge switch 400 may be controlled to control the charge current during the charge process, and similarly, the charge switch 300 and the discharge switch 400 may be controlled to control the discharge current during the discharge process.

In summary, the N-stage slave battery chip receives the state information from the previous-stage slave battery chip from the current-stage slave battery chip, and the current-stage slave battery chip processes the state information of the current-stage series lithium battery cell acquired from the current-stage slave battery chip by the current-stage slave battery chip and the state information received from the previous-stage slave battery chip, and transfers the processing result of the current-stage slave battery chip to the next-stage slave battery chip, and the next-stage slave battery chip processes the state information of the next-stage series lithium battery cell acquired from the next-stage slave battery chip and the processing result received from the current-stage slave battery chip, and obtains the processing result of the next-stage slave battery chip until all the processing results of the slave battery chips are transferred to the master battery chip.

In the present disclosure, the information is transmitted through an uplink, for example, the nth level slave battery chip transmits the status information of the nth level lithium battery cell to the N-1 th level slave battery chip, the nth level slave battery chip may transmit information through an uplink transmission port DTX, and the N-1 th level slave battery chip may receive information through an uplink reception port DRX. And the (N-1) th level slave battery chip processes the state information of the (N) th level lithium battery unit and the state information of the (N-1) th level lithium battery unit, sends the processing result to an uplink receiving port DRX of the (N-2) th level slave battery chip through an uplink sending port DTX of the (N-1) th level slave battery chip, and repeats the operation until the master battery chip receives the information through the uplink receiving port DRX, and processes the received information and the state information of the first level lithium battery unit 201 by the master battery chip, so that the state information of the series lithium battery stacking system is finally obtained.

In addition, the main battery chip 101 is also used to detect a current passing through the stacked system. For example, a detection resistor 500 may be connected in series in a current path of the stack system, and the main battery chip 101 obtains a voltage value across the detection resistor 500 through the detection ports SRP and SRN, and obtains a value of a current flowing therethrough according to the voltage value. The slave battery chip is not used for detecting the current, and only the master battery chip is used for detecting the current, so that the power consumption of the chip can be obviously reduced.

The main battery chip 101 may serve as a control factor of the charge switch 300 and the discharge switch 400 according to the detected current value.

As shown in fig. 1, the charge switch 300 and the discharge switch 400 may be MOSFETs and may be connected in series, for example, drains of the two may be interconnected, sources of the two may be connected to both sides, and a control signal of the main battery chip 101 may control gates of the two.

In fig. 1, the charge switch 300 and the discharge switch 400 are shown connected to the low voltage side of the stacked system, but it is understood by those skilled in the art that they may be connected to the high voltage side, and the connection order of the chips may be arranged right up and down.

The specific processing of the chip will be described below with respect to the uplink.

In the case where the state information is the event flag, the N-level is transmitted from the battery chip of the previous stage to the current stage from the battery chip, and the processing result obtained by performing bit-wise or processing on the event flag of the battery chip and the event flag acquired from the battery chip of the current stage is transmitted to the next-stage slave battery chip or the master battery chip, or the current-stage slave battery chip transmits the event flag acquired from the battery chip of the current stage to the next-stage slave battery chip or the master battery chip.

As an example, in the case of having one main battery chip and one slave battery chip, the event flag collected from the battery chip is transmitted to the main battery chip, and the main battery chip performs bit-wise or processing according to the event flag collected by itself and the event flag collected from the battery chip. For example, when the event flag of the slave battery chip is 1 and the event flag collected by the master battery chip is 1, the master battery chip finally determines that the obtained event flag is 1; when the event mark of the slave battery chip is 0 and the event mark acquired by the master battery chip is 1, the master battery chip finally judges that the obtained event mark is 1; when the event mark of the slave battery chip is 1 and the event mark acquired by the master battery chip is 0, the master battery chip finally judges that the obtained event mark is 1; when the event mark of the slave battery chip is 0 and the event mark acquired by the master battery chip is 0, the master battery chip finally judges that the obtained event mark is 0. And the main battery chip takes the processing result of the event mark transmitted from the battery chip to the main battery chip and the event mark obtained by the main battery chip as the event mark of the serial lithium battery stacking system according to the position or after the processing.

As another example, in the case of having one master battery chip and two slave battery chips, the event flag collected by the second slave battery chip is transmitted to the first slave battery chip, and the first slave battery chip performs bit-wise or processing according to the event flag collected by itself and the event flag collected by the second slave battery chip. For example, when the event flag of the secondary battery chip of the second stage is 1, and the event flag collected from the battery chip of the first stage is 1, the event flag finally judged and obtained by the secondary battery chip of the first stage is 1; when the event mark of the secondary battery chip of the second level is 0 and the event mark acquired from the battery chip of the first level is 1, the event mark finally judged and obtained by the secondary battery chip of the first level is 1; when the event mark of the secondary battery chip of the second level is 1 and the event mark acquired from the battery chip of the first level is 0, the event mark finally judged and obtained by the secondary battery chip of the first level is 1; when the event flag of the secondary battery chip of the second level is 0 and the event flag collected from the battery chip of the first level is 0, the event flag finally judged and obtained by the secondary battery chip of the first level is 0.

The first-level slave battery chip transmits the finally obtained event mark to the master battery chip. And the main battery chip carries out bit-based or processing according to the acquired event marks and the event marks of the first-level slave battery chip. For example, when the event flag of the first-level slave battery chip is 1 and the event flag acquired by the master battery chip is 1, the master battery chip finally determines that the obtained event flag is 1; when the event mark of the first-stage slave battery chip is 0 and the event mark acquired by the main battery chip is 1, the main battery chip finally judges that the obtained event mark is 1; when the event mark of the first-stage slave battery chip is 1 and the event mark acquired by the main battery chip is 0, the main battery chip finally judges that the obtained event mark is 1; when the event mark of the first-stage slave battery chip is 0 and the event mark acquired by the main battery chip is 0, the main battery chip finally judges that the obtained event mark is 0. And the main battery chip takes the processing result of the event mark transmitted from the battery chip to the main battery chip in the first stage and the event mark acquired by the main battery chip as the event mark of the serial lithium battery stacking system according to the position or after the processing. The main battery chip may control the charge switch 300 and the discharge switch 400 to control the charge and discharge current according to the final processing result.

In the case where the state information is the lowest voltage of the lithium battery cell, the N-level is transmitted from the battery chip to the current stage from the previous stage of the battery chip from the minimum value between the lowest voltage of the lithium battery cell of the battery chip and the lowest voltage of the lithium battery cell acquired from the battery chip at the current stage to the next stage from the battery chip or the main battery chip, or the lowest voltage of the lithium battery cell acquired from the battery chip at the current stage is transmitted to the next stage from the battery chip or the main battery chip.

And the main battery chip takes the minimum value of the lowest voltage of the lithium battery unit transmitted to the main battery chip from the battery chip and the lowest voltage of the lithium battery unit obtained by the main battery chip as the lowest voltage of the lithium battery unit of the series lithium battery stacking system.

As an example, in the case of having one main battery chip and one slave battery chip, the lowest voltage of the lithium battery cell collected from the battery chip is transmitted to the main battery chip, and the main battery chip processes the lowest voltage of the lithium battery cell collected by itself and the lowest voltage collected from the battery chip, and obtains the lowest voltage therebetween. The main battery chip takes the lowest voltage obtained by judging the lowest voltage transmitted from the battery chip to the main battery chip and the lowest voltage obtained by the main battery chip as a processing result, and the lowest voltage is regarded as the lowest voltage of the series lithium battery stacking system.

As another example, in the case of having one master battery chip and two slave battery chips, the lowest voltage collected by the second slave battery chip is transmitted to the first slave battery chip, and the first slave battery chip processes the lowest voltage collected by itself and the lowest voltage collected by the second slave battery chip to obtain the lowest voltage.

The first stage transmits the obtained lowest voltage to the main battery chip from the battery chip. The main battery chip is processed according to the lowest voltage acquired by the main battery chip and the lowest voltage of the first-stage slave battery chip to obtain a lowest voltage again. This lowest voltage is taken as the lowest voltage of the shown series lithium battery stack system. The main battery chip may control the charge switch 300 and the discharge switch 400 to control the charge and discharge current according to the final processing result.

In the above description, the state information is exemplified as the lowest voltage of the lithium battery cell and the state information is exemplified as the event flag, respectively, but in the present disclosure, the lowest voltage of the lithium battery cell and the event flag may be simultaneously used as the state information, and the main battery chip may control the charge switch 300 and the discharge switch 400 according to the state information to control the charge and discharge current. Further, as described above, it is also possible to consider the information of the current detected by the main battery chip, while serving as a factor of the switching control.

In addition, in the present disclosure, the master battery chip may transmit the state information of the serial lithium battery stack system to the slave battery chips, so that the N-level slave battery chips perform the balancing determination on the single battery corresponding to the current level slave battery chip according to the received state information of the serial lithium battery stack system.

After the master battery chip obtains the final state information, the final state information may be transmitted to each slave battery chip through a downlink, for example, the master battery chip 101 may transmit the final state information to the first-stage slave battery chip 102 through a downlink transmission port UTX, and the first-stage slave battery chip 102 receives the final state information through a reception port URX, and then the first-stage slave battery chip 102 transmits the final state information to the second-stage slave battery chip … … through the transmission port UTX until the final state information is transmitted to the nth-stage slave battery chip 10N.

And each slave battery chip performs balance judgment according to the received final state information and the state information of the battery unit of the current stage.

In the disclosure, an uplink and a downlink are formed between the slave battery chip and the master battery chip, wherein the downlink is used for transmitting the state information of the series lithium battery unit from the slave battery chip to the master battery chip step by step, and the uplink is used for transmitting the system state information of the series lithium battery stacking system from the master battery chip to the N-level slave battery chip step by step. Thereby enabling a two-wire duplex asynchronous communication system to be formed between the master battery chip and the slave battery chip.

In addition, communication frames in a preset format are adopted for communication between the N-level slave battery chips and the master battery chip. The information transmitted by the communication frame in the preset format comprises an event mark and the minimum voltage of the lithium battery unit.

Specifically, as shown in FIG. 3, the communication frame includes synchronization signals B0-B4, frame content (Event Flag; Min. Voltage), and parity P; the synchronization signal may be a binary number 11110, but other binary numbers may be selected as the synchronization signal.

The communication frame content includes two parts, the first part is an event flag, such as charge protection, discharge protection and precharge state; the second part is the minimum voltage of the lithium battery cell.

In the serial lithium battery stack system, an uplink is used to collect an event flag and a minimum voltage value of each slave battery chip.

If the current battery chip works in the slave mode, the event mark transmitted to the next battery chip is the bitwise OR of the event mark transmitted from the previous stage and the event mark at the current stage, and the lowest voltage of the lithium battery unit transmitted to the next stage is the minimum value of the lowest voltage of the lithium battery unit transmitted from the previous stage and the lowest voltage of the lithium battery unit at the current stage.

If the current battery chip works in the master mode, the event marks of the communication frame contents are the event marks transmitted from the previous stage and the event marks of the main battery chip according to the bit or, and the lowest voltage of the lithium battery unit is the minimum value of the lowest voltage of the lithium battery unit transmitted from the previous stage and the lowest voltage of the lithium battery unit of the main battery chip.

Preferably, 64 local clocks are used to transmit the communication frames in an asynchronous communication manner.

The receiving end counts the synchronization pulses by using a local clock, and when the count value M is within a certain range, it is considered that transmission is started.

When a communication frame begins to be transmitted, the communication frame is sampled every M/4 clock cycles. In the present disclosure, a starting point of the window is M/8-2, and an ending point is M/8+2, for a total of 5 sampling points, as shown in FIG. 4.

Preferably, the communication frame is sampled by using soft bits, that is, the high level is taken as +1, the low level is taken as-1, the sum of 5 sampling values in the sampling window is distributed between [ -5,5], if the sum of the sampling values is distributed between [ -1,1], the sampling is determined to be unreliable, the current reception fails, otherwise, the sign bit of the sum of the sampling values is the hard bit output.

In addition, since the slave battery chip does not need to collect charge and discharge currents, the ports SRP and SRN of the slave battery chip may be connected to VCC. By this, the slave battery chip can be configured to operate in the slave mode.

According to an embodiment of the present disclosure, there is also provided a communication method using the above communication apparatus.

Fig. 5 shows a flow chart of the communication method. As shown in fig. 5, the communication method 500 may include the following.

In step 502, the N-level slave battery chips acquire status information of the series lithium battery cells corresponding to each level of slave battery chip.

In step 504, the state information of the series lithium battery cells transferred from the previous stage slave battery chip to the current stage slave battery chip is processed with the state information of the series lithium battery cells acquired from the current stage slave battery chip.

In step 506, the obtained processing result is transmitted to the next-stage slave battery chip or the master battery chip; or, the N-level slave battery chip transmits the state information of the series lithium battery cells acquired by the current-level slave battery chip to the next-level slave battery chip or the master battery chip.

In step 508, the main battery chip is configured to obtain state information of the first-level lithium battery unit corresponding to the main battery chip, process the state information of the series lithium battery unit transmitted from the battery chip to the main battery chip and the state information of the first-level lithium battery unit obtained by the main battery chip, and use a processing result as system state information of the series lithium battery stacking system.

According to a further embodiment, when the state information is an event flag, the N-level is transmitted from the previous level of the battery chip to the current level from the battery chip to the next level from the battery chip or the main battery chip, or the current level from the battery chip transmits the event flag obtained from the current level from the battery chip to the next level from the battery chip or the main battery chip.

And the main battery chip takes the processing result of the event mark transmitted from the battery chip to the main battery chip and the event mark obtained by the main battery chip as the event mark of the serial lithium battery stacking system according to the position or after the processing.

The event flags include a charge protection state, a discharge protection state, and/or a precharge state.

According to a further embodiment, in the case where the state information is the lowest voltage of the lithium battery cell, the N-th order is transmitted from the battery chip to the current stage from the last stage of the battery chip from the minimum value of the lithium battery cell lowest voltage of the battery chip and the lithium battery cell lowest voltage acquired from the battery chip to the next stage from the battery chip or the main battery chip, or the lithium battery cell lowest voltage acquired from the battery chip to the next stage from the battery chip or the main battery chip.

The main battery chip transmits the state information of the serial lithium battery stacking system to the slave battery chip, so that the N-level slave battery chip performs balance judgment on the single battery corresponding to the current-level slave battery chip according to the received state information of the serial lithium battery stacking system.

The N-level slave battery chip and the master battery chip form an uplink and a downlink, wherein the uplink is used for transmitting the state information of the series lithium battery units from the slave battery chip to the master battery chip step by step, and the downlink is used for transmitting the system state information of the series lithium battery stacking system from the master battery chip to the N-level slave battery chip step by step.

And when the current-stage slave battery chip in the N-stage slave battery chips is the slave battery chip farthest from the master battery chip, transmitting the state information of the series lithium battery units acquired by the current-stage slave battery chip to the next-stage slave battery chip or the master battery chip.

Communication frames in a preset format are adopted for communication among the N-level slave battery chips and between the N-level slave battery chips and the main battery chip. The preset format can refer to the above description, and is not described herein again.

The main battery chip receives charge and discharge current information of the series lithium battery stacking system, and the N-level slave battery chip does not detect the charge and discharge current information.

According to a further embodiment of the present disclosure, there is also provided a series lithium battery stacking system including: the communication device for the series lithium battery stacking system is characterized in that the communication device is used for connecting the lithium batteries in series; and the communication system is used for monitoring the state information of the lithium battery units connected in series. Thereby accurately judging the precharge state, the equalization condition, and the like.

How to obtain the minimum value among the minimum voltages of the lithium battery cells will be described in detail below.

Fig. 6 illustrates a battery voltage detection circuit of a series lithium battery system according to one embodiment of the present disclosure.

As shown in FIG. 6, a battery voltage detection circuit 600 for a series lithium battery system includes N single batteries connected in series, where N ≧ 1, the N single batteries connected in series corresponding to lithium battery cells of each stage (e.g., any one of the first to Nth stages). VC1 to VCn shown in fig. 6 are cell voltages of the n cells, respectively.

The battery voltage detection circuit 600 may include: a multiplexing module 610, a comparator 620, and a reference voltage generating unit 630.

The multiplexing module 610 is connected to the n unit cells connected in series so as to receive the battery voltage signals VC 1-VCn of each of the n unit cells through the multiplexing module and select the battery voltage signal of one of the n unit cells for output at a time.

The comparator 620 is configured to receive the battery voltage signal output by the multiplexing module 610, receive a varying reference voltage value, and compare the received battery voltage signal and the reference voltage value multiple times according to the varying reference voltage value to output a measured voltage of one cell.

The reference voltage value is varied within a preset range from the lowest equalization start voltage to the highest battery voltage, and in the comparison process of the comparator 620, the reference voltage value is varied for each comparison in the process of measuring the battery voltage of each unit battery, and the comparator 610 compares the received battery voltage signal with the reference voltage value varied each time to output the measured voltage of the battery voltage of each unit battery.

The variation of the reference voltage value within the preset range is as follows: the reference voltage value is gradually increased within a preset range, or the reference voltage value is gradually decreased within a preset range.

Presetting n-2 reference voltage points in a preset range, wherein n-2 is a natural number; the reference voltage value is sequentially reduced and changed from the highest voltage, n-2 reference voltage points to the balance initial voltage; or the reference voltage value is increased and changed from the equilibrium initial voltage, the n-2 reference voltage values to the highest voltage in sequence.

When the reference voltage value is one of the highest voltage, n-2 reference voltage points and the balance starting voltage, setting an identification bit corresponding to the current reference voltage value as a first preset value; and when the battery voltage signal output by the multiplexing module is smaller than the current reference voltage value, setting the identification bit corresponding to the current reference voltage value as a second preset value.

And when the battery voltage signal output by the multiplexing module is greater than or equal to the current reference voltage value, taking the first preset value as the identification bit corresponding to the current reference voltage value.

And obtaining the voltage value of each single battery according to the position of the identification bit as the first preset value.

The reference voltage value is represented by m bits, and when the reference voltage value is changed, the highest bit of the m bits is set to 1 and the remaining bits are set to 0 to obtain a first reference voltage value, the first reference voltage value is compared with the received battery voltage signal, if the battery voltage signal is less than the first reference voltage value, the output of the comparator is 0 and the highest bit is set to 0, and if the battery voltage signal is greater than the first reference voltage value, the output of the comparator is 1 and the highest bit is maintained.

If the battery voltage signal is less than the first reference voltage value, the output of the comparator is 0 and the highest bit is set to 0, continuing to set the next bit of the highest bit to 0 and the remaining bits to 0 to obtain a second reference voltage value, comparing the second reference voltage value with the received battery voltage signal, if the battery voltage signal is less than the second reference voltage value, the output of the comparator is 0 and the next bit of the highest bit is set to 0, if the battery voltage signal is greater than the second reference voltage value, the output of the comparator is 1 and the next bit of the highest bit remains unchanged, and if the battery voltage signal is less than the second reference voltage value, continuing to perform the same operation on the other bits.

The reference voltage value is represented by m bits, and when the reference voltage value is changed, the lowest bit of the m bits is set to 1 and the remaining bits are set to 0 to obtain a first reference voltage value, the first reference voltage value is compared with the received battery voltage signal, if the battery voltage signal is less than the first reference voltage value, the output of the comparator is 0 and the lowest bit is set to 0, and if the battery voltage signal is greater than the first reference voltage value, the output of the comparator is 1 and the lowest bit is maintained unchanged.

If the battery voltage signal is less than the first reference voltage value, the output of the comparator is 0 and the lowest bit is set to 0, the last bit of the lowest bit is continuously set to 0 and the remaining bits are set to 0 to obtain a second reference voltage value, the second reference voltage value is compared with the received battery voltage signal, if the battery voltage signal is less than the second reference voltage value, the output of the comparator is 0 and the last bit of the lowest bit is set to 0, if the battery voltage signal is greater than the second reference voltage value, the output of the comparator is 1 and the last bit of the lowest bit is kept unchanged, and if the battery voltage signal is less than the second reference voltage value, the same operation is continuously performed on the other bits.

And multiplexing an overvoltage protection comparator to measure the voltage of the single battery, wherein the reference voltage of the comparator ranges from the lowest equilibrium initial voltage to the highest overvoltage and is represented by N bits. And (3) setting the highest bit of the reference voltage as 1 and the rest bits as 0 at the beginning of measurement, and clearing the highest bit of the reference voltage if the output of the comparator is 0 (the battery voltage is less than the reference voltage), otherwise, keeping the highest bit unchanged. And then, the same operation is carried out on the rest N-1 bits, and when the measurement of the lowest bit is completed, the voltage of the single battery is obtained.

According to another specific embodiment of the present disclosure, the reference voltage ranges from the equilibrium starting voltage V_startTo a maximum voltage V_maxAnd when detecting the voltage of the unit cell to be detected, the range of the reference voltage may be divided into N-1 segments when the difference Δ V between adjacent reference voltages is (V ═ V)_max-V_start) (N-1), wherein N-1 is a natural number.

Defining a data structure with N bits, and enabling each bit from high to low in the data structure with the N bits to correspond to a reference voltage from high to low one by one; that is, the high-to-low zero bit in the data structure corresponds to the highest voltage, and the high-to-low last bit (bit N-1) in the data structure corresponds to the equalizing start voltage; whereby the ith bit from high to low in the data structure corresponds to a reference voltage V_max-. DELTA.V.i, where i is 0, …, N-1.

When the voltage of the single battery to be detected is detected, the value of a bit in the data structure corresponding to the reference voltage is set to be 1, when the voltage of the battery is smaller than the reference voltage, the value of the bit in the data structure is set to be 0, otherwise, the data of the position is kept unchanged.

The reference voltage is changed from high to low in sequence, when the reference voltage is the battery equalization voltage, and after detection is finished, the voltage of the single battery can be obtained.

For example, the output of the multiplexing module is input as the positive terminal of a comparator, and the reference voltage is input as the negative terminal of the comparator; when the detection is started, the reference voltage is the highest voltage, the zero position from high to low in the data structure of N bits is set as 1, and the values of the rest positions are set as 0; if the output of the comparator is 0, namely the battery voltage is less than the reference voltage, setting the value of the bit of the data structure of the N bits corresponding to the reference voltage as 0; and if the comparator output is 1, indicating that the battery voltage is greater than the reference voltage, the value of the bit is held constant.

Next, the reference voltage is reduced to V_max- Δ V, setting the first bit from high to low in the data structure of N bits to 1; if the output of the comparator is 0, namely the battery voltage is less than the reference voltage, setting the value of the bit of the data structure of the N bits corresponding to the reference voltage as 0; and if the comparator output is 1, indicating that the battery voltage is greater than the reference voltage, the value of the bit is held constant.

Sequentially carrying out the steps until the reference voltage is reduced to the battery equalization voltage, setting the last bit from high to low in the data structure of the N bits as 1 at the moment, and setting the bit value of the data structure of the N bits corresponding to the reference voltage as 0 if the output of the comparator is 0, namely the battery voltage is smaller than the reference voltage; and if the comparator output is 1, indicating that the battery voltage is greater than the reference voltage, the value of the bit is held constant.

The battery voltage detection circuit of the series lithium battery system according to an embodiment of the present disclosure further includes a first filter 640, wherein for a same reference voltage value, battery voltage signals output by the multiplexing module are collected at least twice, and the comparator compares the same reference voltage with the battery voltage signals output by the multiplexing module at least twice respectively to obtain at least two comparison results, inputs the at least two comparison results into the first filter, multiplies the at least two comparison results by corresponding weights by the first filter to perform superposition, and outputs the superposed signals.

The first filter is an FIR filter, and for the same reference voltage value, the battery voltage signal output by the quadruple multiplexing module, the same reference voltage and the battery voltage signal output by the quadruple multiplexing module are collected to obtain four comparison results, the FIR filter multiplies the four comparison results by corresponding weights and then superposes the four comparison results, and the superposed signals are output.

When the output of the first filter is within the unreliable range, then the output of the first filter is taken as an unreliable measurement.

As shown in fig. 7, the same reference voltage is sampled 4 times in succession, each sampling result is represented by a soft bit, namely if the high level of the output of the comparator is represented by 1, the low level of the output is represented by-1, the result is distributed in [ -8,8] after passing through an FIR filter with the coefficients of 3,2,2,1, if the result is distributed in [ -2,2], the measurement result is considered to be unreliable, otherwise, the sign bit of the output of the filter is inverted to be used as a hard bit of the output of the comparator.

The battery voltage detection circuit of the series lithium battery system according to one embodiment of the present disclosure further includes a second filter 650 that receives the battery voltage of each unit battery output from the first filter and corrects the battery voltage of each unit battery, taking the corrected battery voltage of each unit battery as a final battery voltage of each unit battery.

As shown in fig. 8, the second filter is a kalman filter. When the battery voltage signal of each single battery is measured, each single battery is measured for multiple times to obtain multiple battery voltage signals, and the average value of the multiple battery voltage signals is used as the initial state value of the Kalman filter.

In one example, the obtained cell voltage is filtered by a kalman filter with a gain of 0.5 to be used as the final cell voltage. In order to enable the Kalman filter to be fast and stable, after the system is powered on, the voltage of each single battery is continuously measured for 16 times, and an average value is taken as the initial state of the Kalman filter. In order to ensure the measurement accuracy, the charge and discharge switch can be closed during the period.

And when the battery voltages of all the single batteries are obtained, the system lowest voltage value of the single batteries in the series lithium battery system is obtained by comparing the battery voltages of all the single batteries.

When the lowest voltage value of the system is higher than the balance initial voltage of the battery, judging whether the difference value between the voltage value of a certain single battery in the series lithium battery system and the lowest voltage value of the system is larger than the balance threshold voltage, and if the difference value is larger than the balance threshold voltage, carrying out balance processing on the single battery.

According to one embodiment of the present disclosure, a communication device of a lithium battery system includes: the lithium battery system comprises a plurality of single batteries connected in series, each battery voltage detection circuit detects n single batteries in the plurality of single batteries connected in series, the lowest voltage value of each single battery in the n single batteries is obtained based on the measurement voltage output by each battery voltage detection circuit, and the lowest voltage value of each single battery obtained by each battery voltage detection circuit is mutually transmitted and judged in each battery voltage detection circuit to obtain the lowest voltage value of the system single battery of the lithium battery system.

According to a further embodiment of the present disclosure, a method for detecting a battery voltage detection circuit of a series lithium battery system, the series lithium battery system including n single batteries connected in series, where n ≧ 1, as shown in fig. 9, may include the following steps.

In step 902, a multiplexing module is connected to the n cells connected in series to receive a cell voltage signal of each of the n cells through the multiplexing module and select a cell voltage signal of one of the n cells at a time for output.

In step 904, the comparator receives the battery voltage signal output by the multiplexing module and the varying reference voltage value, and compares the received battery voltage signal and the reference voltage value multiple times according to the varying reference voltage value to output a measured voltage of a single battery.

In step 906, the reference voltage value is changed within a preset range from the lowest equalization start voltage to the highest battery voltage, and the reference voltage value is changed for each comparison in the process of measuring the battery voltage of each unit battery in the comparison process of the comparator, and the comparator compares the received battery voltage signal with the reference voltage value changed each time to output the measured voltage of the battery voltage of each unit battery.

For the same reference voltage value, battery voltage signals output by the multiplexing module are collected at least twice, the comparator respectively compares the same reference voltage with the battery voltage signals output by the multiplexing module at least twice to obtain at least two comparison results, the at least two comparison results are input into a first filter, the first filter multiplies the at least two comparison results by corresponding weights to carry out superposition, and the superposed signals are output.

The second filter receives the battery voltage of each unit battery output by the first filter, corrects the battery voltage of each unit battery, and takes the corrected battery voltage of each unit battery as the final battery voltage of each unit battery.

The second filter is a kalman filter.

When the battery voltage signal of each single battery is measured, each single battery is measured for multiple times to obtain multiple battery voltage signals, and the average value of the multiple battery voltage signals is used as the initial state value of the Kalman filter.

And when the battery voltages of all the single batteries are obtained, the lowest voltage value of the single batteries in the series lithium battery system is obtained by comparing the battery voltages of all the single batteries.

And when the lowest voltage value is higher than the battery equalization initial voltage, judging whether the difference value between the voltage value of a certain single battery in the series lithium battery system and the lowest voltage value is larger than the equalization threshold voltage, and if the difference value is larger than the equalization threshold voltage, equalizing the single battery.

According to a further embodiment of the present disclosure, a communication method for a lithium battery system is further provided, where the lithium battery system includes two or more battery voltage detection circuits, the lithium battery system includes a plurality of serially connected single batteries, each battery voltage detection circuit detects n single batteries among the plurality of serially connected single batteries, and obtains a minimum voltage value of a single battery among the n single batteries based on a measurement voltage output by each battery voltage detection circuit, and the minimum voltage values of the single batteries obtained by each battery voltage detection circuit are mutually transmitted and judged in each battery voltage detection circuit to obtain a system minimum voltage value of the single batteries of the lithium battery system.

According to a further embodiment of the present disclosure, a battery equalization control method for a lithium battery system is further provided, for example, as shown in fig. 10, a system minimum voltage value is obtained through the above communication method, when the system minimum voltage value is higher than a battery equalization starting voltage, it is determined whether a difference between a voltage value of a certain single battery in a series lithium battery system and the system minimum voltage value is greater than an equalization threshold voltage, and if the difference is greater than the equalization threshold voltage, equalization processing is performed on the single battery.

In the description herein, reference to the description of the terms "one embodiment/mode," "some embodiments/modes," "example," "specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment/mode or example is included in at least one embodiment/mode or example of the application. In this specification, the schematic representations of the terms used above are not necessarily intended to be the same embodiment/mode or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments/modes or examples. Furthermore, the various embodiments/aspects or examples and features of the various embodiments/aspects or examples described in this specification can be combined and combined by one skilled in the art without conflicting therewith.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

It will be understood by those skilled in the art that the foregoing embodiments are merely for clarity of illustration of the disclosure and are not intended to limit the scope of the disclosure. Other variations or modifications may occur to those skilled in the art, based on the foregoing disclosure, and are still within the scope of the present disclosure.

Claims

1. The utility model provides a series lithium battery system's battery voltage detection circuitry, series lithium battery system is including a N battery cell of establishing ties, and wherein N is greater than or equal to 1, its characterized in that includes:

2. The battery voltage detection circuit of a series lithium battery system of claim 1, wherein the reference voltage value varies within a predetermined range by: the reference voltage value is gradually increased within a preset range, or the reference voltage value is gradually decreased within the preset range;

optionally, presetting N-2 reference voltage points in a preset range, wherein N-2 is a natural number; the reference voltage value is sequentially reduced and changed from the highest voltage, N-2 reference voltage points to the balance initial voltage; or the reference voltage value is sequentially increased and changed from the equilibrium initial voltage, the N-2 reference voltage values to the highest voltage;

optionally, when the reference voltage value is one of the highest voltage, N-2 reference voltage points, and the equalization start voltage, setting an identification bit corresponding to the current reference voltage value to a first preset value; and when the battery voltage signal output by the multiplexing module is smaller than the current reference voltage value, setting the identification bit corresponding to the current reference voltage value as a second preset value.

3. The battery voltage detection circuit of the series lithium battery system of claim 1, wherein when the battery voltage signal output by the multiplexing module is greater than or equal to a current reference voltage value, a first preset value is used as an identification bit corresponding to the current reference voltage value;

optionally, obtaining a voltage value of each single battery according to the position of the identification bit with the first preset value;

optionally, the reference voltage value is represented by M bits, when the reference voltage value is changed, the highest bit of the M bits is set to 1 and the remaining bits are set to 0 to obtain a first reference voltage value, the first reference voltage value is compared with the received battery voltage signal, if the battery voltage signal is less than the first reference voltage value, the output of the comparator is 0 and the highest bit is set to 0, and if the battery voltage signal is greater than the first reference voltage value, the output of the comparator is 1 and the highest bit is kept unchanged.

4. The battery voltage detection circuit of the series lithium battery system of claim 1, wherein if the battery voltage signal is less than a first reference voltage value, the output of the comparator is 0 and the highest bit is set to 0, continuing to set a next bit of the highest bit to 0 and the remaining bits to 0 to obtain a second reference voltage value, comparing the second reference voltage value with the received battery voltage signal, if the battery voltage signal is less than a second reference voltage value, the output of the comparator is 0 and the next bit of the highest bit is set to 0, if the battery voltage signal is greater than the second reference voltage value, the output of the comparator is 1 and the next bit of the highest bit is kept unchanged, and if the battery voltage signal is less than the second reference voltage value, continuing to perform the same operation on other bits;

optionally, the reference voltage value is represented by M bits, when the reference voltage value is changed, the lowest bit of the M bits is set to 1 and the remaining bits are set to 0 to obtain a first reference voltage value, the first reference voltage value is compared with the received battery voltage signal, if the battery voltage signal is less than the first reference voltage value, the output of the comparator is 0 and the lowest bit is set to 0, if the battery voltage signal is greater than the first reference voltage value, the output of the comparator is 1 and the lowest bit is kept unchanged;

optionally, if the battery voltage signal is less than a first reference voltage value, the output of the comparator is 0 and the lowest bit is set to 0, the last bit of the lowest bit is set to 0 and the remaining bits are set to 0 to obtain a second reference voltage value, the second reference voltage value is compared with the received battery voltage signal, if the battery voltage signal is less than the second reference voltage value, the output of the comparator is 0 and the last bit of the lowest bit is set to 0, if the battery voltage signal is greater than the second reference voltage value, the output of the comparator is 1 and the last bit of the lowest bit is kept unchanged, and if the battery voltage signal is less than the second reference voltage value, the same operation is continued on the other bits.

5. The battery voltage detection circuit of any one of claims 1 to 4, further comprising a first filter, wherein for a same reference voltage value, the battery voltage signals output by the multiplexing module are collected at least twice, and the comparator compares the same reference voltage with the battery voltage signals output by the multiplexing module at least twice to obtain at least two comparison results, inputs the at least two comparison results into the first filter, and adds the at least two comparison results by multiplying the at least two comparison results by corresponding weights by the first filter, and outputs the added signal;

optionally, the first filter is an FIR filter, and for the same reference voltage value, the battery voltage signal output by the quadruple multiplexing module is collected, the same reference voltage and the battery voltage signal output by the quadruple multiplexing module obtain four comparison results, the FIR filter multiplies the four comparison results by corresponding weights and then superimposes the results, and the superimposed signal is output;

optionally, when the output of the first filter is in an unreliable range, taking the output of the first filter as an unreliable measurement result;

optionally, a second filter is further included, the second filter receives the battery voltage of each unit battery output by the first filter, corrects the battery voltage of each unit battery, and takes the corrected battery voltage of each unit battery as a final battery voltage of each unit battery;

optionally, the second filter is a kalman filter;

optionally, when measuring the battery voltage signal of each single battery, measuring each single battery for multiple times to obtain multiple battery voltage signals, and taking an average value of the multiple battery voltage signals as an initial state value of the kalman filter;

optionally, after the battery voltages of all the single batteries are obtained, the system minimum voltage values of the single batteries in the series lithium battery system are obtained by comparing the battery voltages of the single batteries;

optionally, when the system minimum voltage value is higher than the battery equalization starting voltage, it is determined whether a difference between a voltage value of a certain single battery in the series lithium battery system and the system minimum voltage value is greater than an equalization threshold voltage, and if the difference is greater than the equalization threshold voltage, the single battery is equalized.

6. A communication device of a lithium battery system, comprising: the battery voltage detection circuit of any one of claims 1 to 5,

7. The utility model provides a detection method of battery voltage detection circuit of series lithium battery system, the series lithium battery system includes the N battery cell of establishing ties, and wherein N is greater than or equal to 1, its characterized in that includes:

8. The detection method according to claim 7, wherein the reference voltage value varies within a preset range as follows: the reference voltage value is gradually increased within a preset range, or the reference voltage value is gradually decreased within the preset range;

optionally, when the reference voltage value is one of the highest voltage, N-2 reference voltage points, and the equalization start voltage, setting an identification bit corresponding to the current reference voltage value to a first preset value; when the battery voltage signal output by the multiplexing module is smaller than the current reference voltage value, setting the identification bit corresponding to the current reference voltage value as a second preset value;

optionally, when the battery voltage signal output by the multiplexing module is greater than or equal to the current reference voltage value, taking a first preset value as an identification bit corresponding to the current reference voltage value;

optionally, the reference voltage value is represented by M bits, when the reference voltage value is changed, the highest bit of the M bits is set to 1 and the rest bits are set to 0 to obtain a first reference voltage value, the first reference voltage value is compared with the received battery voltage signal, if the battery voltage signal is less than the first reference voltage value, the output of the comparator is 0 and the highest bit is set to 0, if the battery voltage signal is greater than the first reference voltage value, the output of the comparator is 1 and the highest bit is kept unchanged;

alternatively, if the battery voltage signal is less than a first reference voltage value, the output of the comparator is 0 and the highest bit is set to 0, the next bit of the highest bit is set to 0 and the remaining bits are set to 0 to obtain a second reference voltage value, the second reference voltage value is compared with the received battery voltage signal, if the battery voltage signal is less than the second reference voltage value, the output of the comparator is 0 and the next bit of the highest bit is set to 0, if the battery voltage signal is greater than the second reference voltage value, the output of the comparator is 1 and the next bit of the highest bit is kept unchanged, and if the battery voltage signal is less than the second reference voltage value, the same operation is continued for the other bits.

9. A communication method of a lithium battery system, wherein the lithium battery system comprises two or more battery voltage detection circuits according to any one of claims 1 to 5,

10. The battery equalization control method of the lithium battery system is characterized in that the system minimum voltage value is obtained through the communication method according to claim 9, when the system minimum voltage value is higher than the battery equalization initial voltage, whether the difference value between the voltage value of a certain single battery in the series lithium battery system and the system minimum voltage value is larger than an equalization threshold voltage or not is judged, and if the difference value is larger than the equalization threshold voltage, equalization processing is carried out on the single battery.