Battery cell voltage detection method, battery cell voltage detection circuit and battery management system

Abstract

The present application discloses a battery cell voltage detection method, a battery cell voltage detection circuit and a battery management system, and relates to the field of battery detection technology. The method comprises: for a target battery cell among a plurality of battery cells connected in series, determining a first voltage value detected by a target battery cell voltage detection channel corresponding to the target battery cell, and determining a second voltage value detected by a target voltage equalization detection channel corresponding to the target battery cell; when it is determined that the absolute difference between the first voltage value and the second voltage value is greater than or equal to a preset threshold value, performing a validity check on the target voltage equalization detection channel; when it is determined that the validity check of the target voltage equalization detection channel passes, adopting the second voltage value detected by the target voltage equalization detection channel. The present application can improve the credibility of battery cell voltage detection, and avoid the situation where the vehicle breaks down or the battery is overcharged or over-discharged, or even catches fire, due to a large deviation between the detected battery cell voltage value and the actual battery cell voltage value.

Description

Technical Field

[0001] The present application relates to the technical field of battery detection, and in particular to a battery cell voltage detection method, a battery cell voltage detection circuit and a battery management system. Background Art

[0002] As electric vehicles become more and more popular and their market share increases, some corresponding reliability issues are gradually emerging, such as the monitoring reliability of power batteries. Limited by material costs, the current mainstream of power battery cell voltage detection is to detect the cell voltage through a detection channel. If the chip used to implement this detection channel fails, the cell voltage value detected through this detection channel will deviate significantly from the actual cell voltage value, and the deviation cannot be identified and eliminated at this time, which may cause the vehicle to break down at the least, or the battery to overcharge, over-discharge, or even catch fire at the worst. Summary of the invention

[0003] In response to the above technical problems, the embodiments of the present application provide a battery cell voltage detection method, a battery cell voltage detection circuit and a battery management system, which can improve the credibility of battery cell voltage detection and avoid vehicle breakdown or battery overcharge or overdischarge or even fire due to a large deviation between the detected battery cell voltage value and the actual battery cell voltage value.

[0004] The technical solution of this application is implemented as follows:

[0005] In a first aspect, an embodiment of the present application provides a cell voltage detection method, which is applied to a cell voltage detection circuit, wherein the cell voltage detection circuit includes a plurality of cell voltage detection channels and a plurality of voltage equalization detection channels, wherein the plurality of cell voltage detection channels and the plurality of voltage equalization detection channels both have the function of detecting the voltages of a plurality of cell connected in series, and the plurality of cell voltage detection channels and the plurality of voltage equalization detection channels correspond one-to-one to the plurality of cell connected in series; the method includes:

[0006] For any one target cell among the plurality of cells connected in series, determining a first voltage value detected by a target cell voltage detection channel corresponding to the target cell, and determining a second voltage value detected by a target voltage equalization detection channel corresponding to the target cell;

[0007] determining an absolute difference between the first voltage value and the second voltage value;

[0008] When it is determined that the absolute difference is greater than or equal to a preset threshold value, performing validity verification on the target voltage balance detection channel;

[0009] When it is determined that the validity check of the target voltage balance detection channel passes, the second voltage value detected by the target voltage balance detection channel is adopted.

[0010] In some embodiments, the plurality of voltage balance detection channels further have the function of detecting the voltage balance of the plurality of battery cells connected in series;

[0011] The performing validity check on the target voltage balance detection channel includes:

[0012] Determining a voltage equalization detection channel adjacent to the target voltage equalization detection channel;

[0013] In the case where it is determined that a voltage balance detection function of a voltage balance detection channel adjacent to the target voltage balance detection channel is turned on, determining a third voltage value detected by the target voltage balance detection channel;

[0014] Based on the third voltage value and the second voltage value, the target voltage balance detection channel is verified for validity.

[0015] In some embodiments, the performing validity verification on the target voltage balance detection channel based on the third voltage value and the second voltage value includes:

[0016] Determining a ratio of the third voltage value to the second voltage value;

[0017] When it is determined that the ratio value is within a preset range, determining that the validity check of the target voltage balance detection channel passes;

[0018] When it is determined that the ratio value is not within the preset range, it is determined that the validity check of the target voltage balance detection channel fails.

[0019] In some embodiments, the method further comprises:

[0020] When it is determined that the validity check of the target voltage equalization detection channel fails, the first voltage value detected by the target cell voltage detection channel is adopted.

[0021] In some embodiments, the method further comprises:

[0022] When it is determined that the absolute difference is less than the preset threshold value, the first voltage value detected by the target cell voltage detection channel is adopted.

[0023] In a second aspect, an embodiment of the present application provides a cell voltage detection circuit, comprising: a plurality of cell voltage detection channels and a plurality of voltage equalization detection channels, wherein the plurality of cell voltage detection channels and the plurality of voltage equalization detection channels both have the function of detecting the voltages of a plurality of cell connected in series, and the plurality of cell voltage detection channels and the plurality of voltage equalization detection channels correspond one to one to the plurality of cell connected in series;

[0024] Any target voltage equalization detection channel among the plurality of voltage equalization detection channels comprises a first branch circuit and a second branch circuit;

[0025] One end of the first branch circuit is connected to the negative electrode of the first battery cell, and one end of the second branch circuit is connected to the positive electrode of the first battery cell and the negative electrode of the second battery cell; the first battery cell is a battery cell corresponding to the target voltage equalization detection channel among the plurality of battery cells connected in series, and the second battery cell is a battery cell adjacent to the first battery cell;

[0026] The first branch circuit and the second branch circuit each include at least one equivalent resistor connected in series, and the number of the equivalent resistors included in the first branch circuit is different from the number of the equivalent resistors included in the second branch circuit.

[0027] In some embodiments, the other end of the first branch circuit and the other end of the second branch circuit are connected via a switch;

[0028] When the switch is turned on, the target voltage balance detection channel has a function of detecting the voltage balance of the first battery cell.

[0029] In some embodiments, any target cell voltage detection channel among the plurality of cell voltage detection channels includes a third branch circuit and a fourth branch circuit;

[0030] The third branch circuit and the fourth branch circuit each include a resistor of equal value;

[0031] The third branch circuit and the fourth branch circuit are respectively connected to the positive electrode and the negative electrode of the third battery cell; the third battery cell is a battery cell corresponding to the target battery cell voltage detection channel among the plurality of battery cells connected in series.

[0032] In some embodiments, the plurality of voltage equalization detection channels are numbered in sequence according to the arrangement order of the plurality of battery cells connected in series;

[0033] When the number of the target voltage equalization detection channel is odd, the ratio of the number of the equivalent resistors included in the first branch circuit to the number of the equivalent resistors included in the second branch circuit is N:1;

[0034] When the number of the target voltage balance detection channel is an even number, the ratio of the number of the equivalent resistors included in the first branch circuit to the number of the equivalent resistors included in the second branch circuit is 1:N;

[0035] Wherein, N is a positive integer greater than or equal to 2.

[0036] In a third aspect, an embodiment of the present application provides a battery management system, comprising the battery cell voltage detection circuit described in the second aspect.

[0037] The battery cell voltage detection method, battery cell voltage detection circuit and battery management system provided by the embodiments of the present application perform validity verification on the target voltage equalization detection channel when it is determined that the absolute difference between a first voltage value detected by a target battery cell voltage detection channel corresponding to a target battery cell in a plurality of battery cells connected in series and a second voltage value detected by a target voltage equalization detection channel corresponding to the target battery cell is greater than or equal to a preset threshold value, and when it is determined that the validity verification of the target voltage equalization detection channel passes, the second voltage value detected by the target voltage equalization detection channel is adopted; that is, the embodiments of the present application simultaneously utilize the voltage detection functions of the battery cell voltage detection channel and the voltage equalization detection channel, and when it is determined that the validity verification of the target voltage equalization detection channel passes, the second voltage value detected by the target voltage equalization detection channel is adopted. When the absolute difference between the first voltage value detected by the measurement channel and the second voltage value detected by the voltage equalization detection channel is greater than or equal to the preset threshold value, it indicates that a deviation fault has occurred in the target battery cell voltage detection channel or the target voltage equalization detection channel. At this time, the validity of the target voltage equalization detection channel is checked. If the validity check of the target voltage equalization detection channel passes, it indicates that there is no deviation fault in the target voltage equalization detection channel. The second voltage value detected by the target voltage equalization detection channel is adopted, which effectively improves the credibility of the battery cell voltage detection and avoids the vehicle breaking down or the battery overcharging or over-discharging or even fire due to a large deviation between the detected battery cell voltage value and the actual voltage value of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0039] Figure 1 One of the flow charts of a method for detecting a cell voltage provided in an embodiment of the present application;

[0040] Figure 2 A second flow chart of a method for detecting a cell voltage provided in an embodiment of the present application;

[0041] Figure 3 One of the structural schematic diagrams of a battery cell voltage detection circuit provided in an embodiment of the present application;

[0042] Figure 4 A schematic diagram of a cell voltage detection circuit provided for related technology;

[0043] Figure 5 This is a second structural schematic diagram of a battery cell voltage detection circuit provided in an embodiment of the present application. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0045] It should be noted that in the description of the embodiments of the present application, the terms "first", "second", etc. are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of the same type, and the number of objects is not limited. For example, the first object can be one or more.

[0046] The following is an illustrative introduction to the battery cell voltage detection method, battery cell voltage detection circuit and battery management system provided in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application.

[0047] Figure 1 This is one of the flow charts of a method for detecting a cell voltage provided in an embodiment of the present application. The method is applied to Figure 3 The cell voltage detection circuit shown in the figure comprises a plurality of cell voltage detection channels 301 and a plurality of voltage equalization detection channels 302. The plurality of cell voltage detection channels 301 and the plurality of voltage equalization detection channels 302 both have the function of detecting the voltages of a plurality of cell connected in series, and the plurality of cell voltage detection channels 301 and the plurality of voltage equalization detection channels 302 correspond one to one with the plurality of cell connected in series; wherein the plurality of cell connected in series is Figure 3 Cell 1, cell 2, ..., cell n.

[0048] like Figure 1As shown, the cell voltage detection method provided in the embodiment of the present application includes:

[0049] S101 . For any target cell among the plurality of cells connected in series, determine a first voltage value detected by a target cell voltage detection channel corresponding to the target cell, and determine a second voltage value detected by a target voltage equalization detection channel corresponding to the target cell.

[0050] In some embodiments, if it is necessary to monitor a target battery cell among multiple battery cells connected in series, a first voltage value detected by a target battery cell voltage detection channel corresponding to the target battery cell is determined based on a battery cell voltage detection circuit, and a second voltage value detected by a target voltage equalization detection channel corresponding to the target battery cell is determined.

[0051] For example, if you need to Figure 3 If the battery cell 1 is monitored, then based on Figure 3 The cell voltage detection circuit shown determines a first voltage value detected by a cell voltage detection channel corresponding to cell 1 , and determines a second voltage value detected by a voltage equalization detection channel corresponding to cell 1 .

[0052] For example, if you need to Figure 3 The battery cell 2 in the Figure 3 The cell voltage detection circuit shown determines a first voltage value detected by a cell voltage detection channel corresponding to the cell 2 , and determines a second voltage value detected by a voltage equalization detection channel corresponding to the cell 2 .

[0053] S102: Determine an absolute difference between the first voltage value and the second voltage value.

[0054] In some embodiments, after obtaining a first voltage value detected by a target cell voltage detection channel corresponding to the target cell and a second voltage value detected by a target voltage equalization detection channel corresponding to the target cell, an absolute difference between the first voltage value and the second voltage value may be determined.

[0055] For example, if the first voltage value is U1 and the second voltage value is U2, then the absolute difference between U1 and U2 is ΔU=|U1-U2|.

[0056] S103: When it is determined that the absolute difference is greater than or equal to a preset threshold value, perform validity verification on the target voltage balance detection channel.

[0057] In some embodiments, if it is determined that the absolute difference between the first voltage value and the second voltage value is greater than or equal to a preset threshold value, a validity check is performed on the target voltage balance detection channel.

[0058] It should be noted that the preset threshold value can be adaptively set based on actual applications, and the present application embodiment does not specifically limit this. For example, the preset threshold value is 0.2, 0.5 or 0.8, etc., and the unit is volt, represented by "V".

[0059] It should be noted that if the absolute difference between the first voltage value and the second voltage value is greater than or equal to the preset threshold value, it indicates that the voltage value deviation of the target battery cell voltage detection channel and the voltage equalization detection channel to the target battery cell detection is large, which means that a deviation fault has occurred in the target battery cell voltage detection channel or the target voltage equalization detection channel. At this time, the validity of the target voltage equalization detection channel is checked to verify whether a deviation fault has occurred in the target voltage equalization detection channel.

[0060] S104: When it is determined that the validity check of the target voltage balance detection channel has passed, the second voltage value detected by the target voltage balance detection channel is adopted.

[0061] In some embodiments, when it is determined that the validity check of the target voltage balance detection channel has passed, it indicates that there is no deviation fault in the target voltage balance detection channel, which means that the second voltage value detected by the target voltage balance detection channel is accurate, and the second voltage value detected by the target voltage balance detection channel is adopted.

[0062] It should be noted that the concept of the battery cell voltage detection method provided in the embodiment of the present application is: to use the battery cell voltage value detected by the voltage equalization detection channel as a backup of the battery cell voltage value detected by the battery cell voltage detection channel to correct the battery cell voltage deviation in the event of chip failure in the battery cell voltage detection channel.

[0063] It can be understood that the battery cell voltage detection method provided in the embodiment of the present application performs a validity check on the target voltage equalization detection channel when it is determined that the absolute difference between a first voltage value detected by a target battery cell voltage detection channel corresponding to a target battery cell in a plurality of battery cells connected in series and a second voltage value detected by a target voltage equalization detection channel corresponding to the target battery cell is greater than or equal to a preset threshold value, and when it is determined that the validity check of the target voltage equalization detection channel passes, the second voltage value detected by the target voltage equalization detection channel is adopted; that is, the embodiment of the present application simultaneously utilizes the voltage detection functions of the battery cell voltage detection channel and the voltage equalization detection channel, and when it is determined that the battery cell voltage detection channel detects When the absolute difference between the first voltage value and the second voltage value detected by the voltage equalization detection channel is greater than or equal to the preset threshold value, it indicates that a deviation fault has occurred in the target battery cell voltage detection channel or the target voltage equalization detection channel. At this time, the validity of the target voltage equalization detection channel is verified. If the validity check of the target voltage equalization detection channel passes, it indicates that there is no deviation fault in the target voltage equalization detection channel. The second voltage value detected by the target voltage equalization detection channel is adopted, which effectively improves the credibility of the battery cell voltage detection and avoids the vehicle breaking down or the battery overcharging or over-discharging or even fire due to a large deviation between the detected battery cell voltage value and the actual voltage value of the battery cell.

[0064] In some embodiments, the plurality of voltage balance detection channels further have the function of detecting the voltage balance of the plurality of battery cells connected in series;

[0065] The performing validity check on the target voltage balance detection channel includes:

[0066] Determining a voltage equalization detection channel adjacent to the target voltage equalization detection channel;

[0067] In the case where it is determined that a voltage balance detection function of a voltage balance detection channel adjacent to the target voltage balance detection channel is turned on, determining a third voltage value detected by the target voltage balance detection channel;

[0068] Based on the third voltage value and the second voltage value, the target voltage balance detection channel is verified for validity.

[0069] It should be noted that, in addition to the function of detecting the voltage of the battery cell, the voltage balance detection channel in the embodiment of the present application also has the function of detecting the voltage balance of the battery cell.

[0070] In an embodiment of the present application, in order to implement a validity check on a target voltage balance detection channel, a voltage balance detection channel adjacent to the target voltage balance detection channel can be first determined, and then, when it is determined that the voltage balance detection function of the voltage balance detection channel adjacent to the target voltage balance detection channel is turned on, a third voltage value detected by the target voltage balance detection channel is determined, and then, based on the third voltage value and the second voltage value, a validity check is performed on the target voltage balance detection channel to verify whether a deviation fault occurs in the target voltage balance detection channel.

[0071] It can be understood that the embodiment of the present application effectively implements the validity verification of the target voltage balance detection channel by utilizing the voltage balance detection function of the voltage balance detection channel adjacent to the target voltage balance detection channel.

[0072] In some embodiments, the performing validity verification on the target voltage balance detection channel based on the third voltage value and the second voltage value includes:

[0073] Determining a ratio of the third voltage value to the second voltage value;

[0074] When it is determined that the ratio value is within a preset range, determining that the validity check of the target voltage balance detection channel passes;

[0075] When it is determined that the ratio value is not within the preset range, it is determined that the validity check of the target voltage balance detection channel fails.

[0076] In an embodiment of the present application, in order to implement validity verification of the target voltage balance detection channel based on the third voltage value and the second voltage value, the ratio of the third voltage value to the second voltage value can be first determined, and then if it is determined that the ratio is within a preset range, it is determined that the validity verification of the target voltage balance detection channel has passed; if it is determined that the ratio is not within the preset range, it is determined that the validity verification of the target voltage balance detection channel has failed.

[0077] It should be noted that the preset range needs to be set based on the specific design of the voltage balancing detection channel in the battery cell voltage detection circuit, and the embodiments of the present application do not specifically limit this.

[0078] For example, if the voltage balancing detection channel in the cell voltage detection circuit includes a first branch circuit and a second branch circuit, and the ratio of the number of equivalent resistors included in the first branch circuit to the number of equivalent resistors included in the second branch circuit is 4:1, the preset range can be set to Wherein σ can be adaptively set based on actual application, and the embodiment of the present application does not specifically limit this. For example, the value of σ is 0.001, 0.0001 or 0.00001.

[0079] In some embodiments, the cell voltage detection method further includes:

[0080] When it is determined that the validity check of the target voltage equalization detection channel fails, the first voltage value detected by the target cell voltage detection channel is adopted.

[0081] In an embodiment of the present application, if it is determined that the validity check of the target voltage equalization detection channel fails, it indicates that a deviation fault has occurred in the target voltage equalization detection channel, which means that the second voltage value detected by the target voltage equalization detection channel is inaccurate, then the first voltage value detected by the target battery cell voltage detection channel is adopted.

[0082] In some embodiments, the cell voltage detection method further includes:

[0083] When it is determined that the absolute difference is less than the preset threshold value, the first voltage value detected by the target cell voltage detection channel is adopted.

[0084] In an embodiment of the present application, if it is determined that the absolute difference between the first voltage value and the second voltage value is less than a preset threshold value, it indicates that the voltage values ​​detected by the target battery cell voltage detection channel and the voltage equalization detection channel for the target battery cell are basically consistent, which means that there is no deviation fault in the target battery cell voltage detection channel and the target voltage equalization detection channel. At this time, the first voltage value detected by the target battery cell voltage detection channel can be trusted.

[0085] In some embodiments, if it is determined that the absolute difference between the first voltage value and the second voltage value is less than a preset threshold value, the second voltage value detected by the target voltage balance detection channel may also be trusted.

[0086] For example, Figure 2 This is a second flow chart of a method for detecting a cell voltage provided in an embodiment of the present application. The flow of the method can be run periodically. Figure 2 As shown, the method includes:

[0087] S201 , calculating an absolute difference between a first voltage value detected by a cell voltage detection channel and a second voltage value detected by a voltage equalization detection channel.

[0088] S202, determining whether the absolute difference between the first voltage value and the second voltage value is less than a preset threshold value; if so, executing S203; if not, executing S204.

[0089] S203 , accepting a first voltage value detected by a cell voltage detection channel.

[0090] S204: Determine that a deviation fault occurs in the cell voltage detection channel or the voltage equalization detection channel, and record and report the fault.

[0091] S205: Perform validity check on the voltage balance detection channel.

[0092] S206, determine whether the validity check of the voltage balance detection channel passes; if passed, execute S207; if not, execute S208.

[0093] S207 , adopting the second voltage value detected by the voltage equalization detection channel.

[0094] S208, determining that a deviation fault occurs in the voltage balancing detection channel, recording and reporting the fault; and then executing S203.

[0095] It should be noted that the cell voltage detection channel and the voltage equalization detection channel in the embodiment of the present application may be the cell voltage detection channel and the voltage equalization detection channel corresponding to any one of the series-connected cells of the power battery.

[0096] It should be noted that the specific method for verifying the validity of the voltage balancing detection channel in S205 can be based on Figure 5 The cell voltage detection circuit shown is implemented, and the method for verifying the validity is described in detail below.

[0097] It can be understood that the embodiments of the present application can be used to determine whether the battery cell voltage detection channel is reliable, and based on the judgment logic, select the voltage data detected by the battery cell voltage detection channel and the voltage equalization detection channel to improve the reliability of voltage detection, so that when the battery cell voltage detection has a voltage deviation due to chip failure, the voltage deviation can be discovered and corrected in time to avoid vehicle breakdown, erroneous equalization action, or battery overcharge and overdischarge, or even fire.

[0098] The cell voltage detection circuit provided in the embodiment of the present application is introduced in detail below.

[0099] Figure 3 This is one of the structural schematic diagrams of a cell voltage detection circuit provided in an embodiment of the present application, such as Figure 3 As shown, the cell voltage detection circuit includes: a plurality of cell voltage detection channels 301 and a plurality of voltage equalization detection channels 302, wherein the plurality of cell voltage detection channels 301 and the plurality of voltage equalization detection channels 302 have the function of detecting the voltages of a plurality of cells connected in series, and the plurality of cell voltage detection channels 301 and the plurality of voltage equalization detection channels 302 correspond one to one to the plurality of cells connected in series; wherein the plurality of cells connected in series are Figure 3 Cell 1, cell 2, ..., cell n.

[0100] In some embodiments, any target voltage balancing detection channel among the plurality of voltage balancing detection channels 302 includes a first branch circuit and a second branch circuit;

[0101] One end of the first branch circuit is connected to the negative electrode of the first battery cell, and one end of the second branch circuit is connected to the positive electrode of the first battery cell and the negative electrode of the second battery cell; the first battery cell is a battery cell corresponding to the target voltage balancing detection channel among the multiple battery cells connected in series, and the second battery cell is a battery cell adjacent to the first battery cell.

[0102] It can be understood that in the embodiments of the present application, any voltage balancing detection channel includes a first branch circuit and a second branch circuit, the first branch circuit and the second branch circuit are respectively connected to the positive and negative electrodes of the chip corresponding to the voltage balancing detection channel, and the voltage balancing detection channels corresponding to adjacent chips share a branch circuit.

[0103] In some embodiments, the first branch circuit and the second branch circuit each include at least one equivalent resistor connected in series, and the number of the equivalent resistors included in the first branch circuit is different from the number of the equivalent resistors included in the second branch circuit.

[0104] In the embodiment of the present application, the first branch circuit of the voltage equalization detection channel includes at least one equivalent resistor, and the second branch circuit also includes at least one equivalent resistor, and the number of equivalent resistors included in the first branch circuit and the second branch circuit is different, so that the validity of the voltage equalization detection channel can be checked based on the voltage equalization detection function of the voltage equalization detection channel adjacent to the voltage equalization detection channel.

[0105] It should be noted that the resistance values ​​of the equal-value resistors included in the first branch circuit and the second branch circuit are the same.

[0106] In some embodiments, the other end of the first branch circuit and the other end of the second branch circuit are connected via a switch;

[0107] When the switch is turned on, the target voltage balance detection channel has a function of detecting the voltage balance of the first battery cell.

[0108] It should be noted that the embodiment of the present application optimizes the configuration of the number of equivalent resistors included in the first branch circuit and the second branch circuit of the voltage equalization detection channel, so that when the voltage equalization detection function of the adjacent voltage equalization detection channel is used for validity verification, it is possible to avoid the detected battery cell voltage exceeding the range of the analog-to-digital converter, thereby effectively realizing the validity verification of the voltage equalization detection channel using the voltage difference formed by the voltage equalization detection function of the voltage equalization detection channel.

[0109] In some embodiments, any target cell voltage detection channel among the plurality of cell voltage detection channels includes a third branch circuit and a fourth branch circuit;

[0110] The third branch circuit and the fourth branch circuit each include a resistor of equal value;

[0111] The third branch circuit and the fourth branch circuit are respectively connected to the positive electrode and the negative electrode of the third battery cell; the third battery cell is a battery cell corresponding to the target battery cell voltage detection channel among the plurality of battery cells connected in series.

[0112] In the embodiment of the present application, any cell voltage detection channel includes a third branch circuit and a fourth branch circuit, and the third branch circuit and the fourth branch circuit each include an equal value resistor. Moreover, the third branch circuit and the fourth branch circuit are respectively connected to the positive electrode and the negative electrode of the cell corresponding to the cell voltage detection channel.

[0113] It should be noted that the resistance values ​​of the equal-value resistors included in the third branch circuit and the fourth branch circuit are the same.

[0114] Here, a cell voltage detection circuit provided by the related art is introduced as follows.

[0115] Figure 4 A schematic diagram of a cell voltage detection circuit provided for related technology, such as Figure 4 As shown in the figure, Cellx+1 to Cellx+4 are single power batteries or cells respectively. Figure 4 The figure shows multiple battery cells connected in series. For each voltage balancing detection channel of the series-connected battery cells, two branch circuits are drawn from the positive and negative poles (Vx to Vx+4, etc.) of each battery cell, and the branch circuit of each battery cell includes balancing resistors RBx to RBx+4, and the resistance values ​​of RBx to RBx+4 are equal. The other end of the branch circuit is connected to the balancing port CBx to CBx+4 of the sampling balancing module (usually a chip), and then connected to the balancing switch Kx+1 to Kx+4 in the sampling balancing module. According to Figure 4 The balancing instructions provided by the processing module in the middle, the balancing switches Kx+1~Kx+4 can realize the corresponding switch switching, that is, the corresponding balancing current can be formed, and then the voltage balancing detection function of each series battery cell can be realized. For the validity check of the voltage balancing detection channel, it can be done by Figure 4 The gate and analog-to-digital converter ADC2 below the sampling and equalization module sample the voltage of the equalization port CBx~CBx+4 and convert it into digital quantity, which is then provided to the processing module through the communication module for validity verification to determine whether the detection function of the voltage equalization detection channel is normal.

[0116] For each cell voltage detection channel of the series-connected cells, two branch circuits are drawn from the positive and negative electrodes (Vx to Vx+4, etc.) of each cell, and the branch circuit of each cell includes cell sampling resistors RCx to RCx+4, and the resistance values ​​of RCx to RCx+4 are equal. The other end of the branch circuit is connected to the voltage sampling ports VCx to VCx+4 of the sampling and equalization module. The voltage sampled by VCx to VCx+4 is Figure 4 After the selector above the sampling and equalization module is selected, it is sent to the analog-to-digital converter ADC1 for sampling and conversion into digital quantity, and then provided to the processing module for calculation and processing through the communication module to complete the detection of the voltage of each battery cell.

[0117] It should be noted that one method for checking the validity of the voltage balance detection channel is to form different voltages for sampling and determine whether they are consistent with the expected circuit model calculation results. If they are consistent, it can be determined to be valid. Figure 4 Take the voltage equalization detection channel corresponding to Cellx+2 as an example. Compared with the case where the voltage equalization detection function of the voltage equalization detection channel is not started (i.e., switches Kx+1 to Kx+4 are in the off state), after the voltage equalization detection function of the voltage equalization detection channel corresponding to Cellx+2 is started (i.e., switch Kx+2 is closed), due to the low on-resistance and large deviation of Kx+2, the voltage value sampled by the voltage equalization detection channel is small and the voltage consistency is poor and the distribution is wide, which is prone to misjudgment. If the voltage equalization detection function of the adjacent voltage equalization detection channel is turned on for validity verification, for example, after the voltage equalization detection function of the voltage equalization detection channel corresponding to Cellx+1 is started (i.e., Kx+1 is closed), the equivalent resistance of the equalization resistors RBx, RBx+1 and the switch Kx+1 will divide the voltage of the battery cell Cellx+1, and the voltage drop on the resistor RBx+1 is about half of the voltage of Cellx+1. At this time, the voltage detected by the voltage equalization detection channel corresponding to Cellx+2 is about 1.5 times the battery cell voltage (if the voltage of each battery cell is consistent). Generally, 1.5 times the cell voltage exceeds the measurement range of the analog-to-digital converter ADC2, which will result in invalid data and cause the validity check of the voltage balance detection channel to fail.

[0118] In some embodiments, the measurement range of the analog-to-digital converter ADC2 may be expanded to ensure that the output voltage is within the effective acquisition range.

[0119] For example, Figure 5 The second structural diagram of a cell voltage detection circuit provided in an embodiment of the present application is as follows: Figure 5 As shown, Figure 4The difference is that here the equalizing resistors RBx~RBx+4 are optimized and adjusted to R1~R14 to cooperate with the validity check of the voltage equalization detection channel, where the resistance values ​​of R1~R14 are equal or similar. Figure 4 The cell sampling resistors RCx~RCx+4 are Figure 5 The above is omitted to simplify the example. Taking the voltage balancing detection channel corresponding to Cellx+2 as an example, the voltage balancing detection function of the voltage balancing detection channel corresponding to the adjacent chip Cellx+1 is turned on, and the validity of the voltage balancing detection channel corresponding to Cellx+2 is verified. After closing the balancing switch Kx+1, a balancing current appears on R10~R14, which will cause a voltage division of about 1 / 5 of the Cellx+1 voltage to appear on R10. The voltage collected by the voltage balancing detection channel corresponding to Cellx+2 at this time will be increased by about 1 / 5 of the Cellx+1 voltage compared to before Kx+1 is closed. When the voltage increase ratio is within the preset range, it can be determined that the validity check of the voltage balancing detection channel corresponding to Cellx+2 has passed. Since the voltage of 6 / 5 of the cells does not exceed the range of the analog-to-digital converter ADC2, the data is valid, and the validity check of the voltage balancing detection channel can be realized.

[0120] Taking the voltage balancing detection channel corresponding to Cellx+3 as an example, the voltage balancing detection function of the voltage balancing detection channel corresponding to the adjacent battery cell Cellx+4 is turned on to perform validity verification of the voltage balancing detection channel corresponding to Cellx+3. After closing the balancing switch Kx+4, a balancing current appears on R1~R5, which will cause a voltage division of about 1 / 5 of the Cellx+4 voltage on R5. The voltage collected by the voltage balancing detection channel corresponding to Cellx+3 at this time will be increased by about 1 / 5 of the Cellx+4 voltage compared to before Kx+4 is closed. When the voltage increase ratio is within the preset range, it can be determined that the validity verification of the voltage balancing detection channel corresponding to Cellx+3 has passed.

[0121] In some embodiments, the plurality of voltage equalization detection channels are numbered in sequence according to the arrangement order of the plurality of battery cells connected in series;

[0122] When the number of the target voltage equalization detection channel is odd, the ratio of the number of the equivalent resistors included in the first branch circuit to the number of the equivalent resistors included in the second branch circuit is N:1;

[0123] When the number of the target voltage balance detection channel is an even number, the ratio of the number of the equivalent resistors included in the first branch circuit to the number of the equivalent resistors included in the second branch circuit is 1:N;

[0124] Wherein, N is a positive integer greater than or equal to 2.

[0125] by Figure 5 As an example, for the battery cell Cellx+1, its corresponding number is a single number, and the ratio of the number of equivalent resistors (R11, R12, R13 and R14) included in the first branch circuit of its corresponding voltage equalization detection channel to the number of equivalent resistors (R10) included in the second branch circuit is 4:1.

[0126] by Figure 5 As an example, for the battery cell Cellx+2, its corresponding number is a double number, and the ratio of the number of equivalent resistors (R10) included in the first branch circuit of its corresponding voltage equalization detection channel (that is, the second branch circuit of the voltage equalization detection channel corresponding to the battery cell Cellx+1) to the number of equivalent resistors (R6, R7, R8 and R9) included in the second branch circuit is 1:4.

[0127] It should be noted that the embodiment of the present application optimizes the ratio of the number of equivalent resistors included in the first branch circuit and the second branch circuit of the voltage equalization detection channel, and uses the voltage difference formed by the voltage equalization detection function of the voltage equalization detection channel to verify the validity of the voltage equalization detection channel, so as to ensure that the detection function of the voltage equalization detection channel is credible and avoid the abnormality of the function affecting the normal battery cell voltage detection function.

[0128] It is understandable that the embodiments of the present application can at least bring the following beneficial effects:

[0129] (1) Without adding additional hardware, the voltage balancing detection channel is used to achieve redundant detection of battery cell voltages, thereby improving the reliability of battery cell voltage detection.

[0130] (2) Without adding additional hardware, the effectiveness of the voltage balancing detection channel can be verified by optimizing the resistor distribution ratio between the first branch circuit and the second branch circuit in the voltage balancing detection channel, thereby further improving the reliability of the cell voltage detection.

[0131] An embodiment of the present application also provides a battery management system, which includes a battery cell voltage detection circuit provided by any of the above embodiments, and the battery cell voltage detection circuit is used to detect the voltage and voltage balance of multiple battery cells connected in series.

[0132] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Those of ordinary skill in the art may understand and implement it without creative work.

[0133] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the embodiments of the present application may adopt the form of hardware embodiments, software embodiments, or embodiments in combination with software and hardware. Moreover, the embodiments of the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage and optical storage, etc.) that contain computer-usable program code.

[0134] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0135] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0136] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0137] The above description is merely an optional embodiment of the present application and is not intended to limit the protection scope of the present application.

Claims

1. A method for detecting a cell voltage, characterized in that: Applied to a cell voltage detection circuit, the cell voltage detection circuit includes a plurality of cell voltage detection channels and a plurality of voltage equalization detection channels, the plurality of cell voltage detection channels and the plurality of voltage equalization detection channels all have the function of detecting the voltages of a plurality of cell connected in series, and the plurality of cell voltage detection channels and the plurality of voltage equalization detection channels correspond one to one to the plurality of cell connected in series; any target voltage equalization detection channel among the plurality of voltage equalization detection channels includes a first branch circuit and a second branch circuit; the first branch circuit and the second branch circuit all include at least one equivalent resistor connected in series, and the number of the equivalent resistors included in the first branch circuit is different from the number of the equivalent resistors included in the second branch circuit; the plurality of voltage equalization detection channels also have the function of detecting the voltage equalization of the plurality of cell connected in series; the method includes: For any one target cell among the plurality of cells connected in series, determining a first voltage value detected by a target cell voltage detection channel corresponding to the target cell, and determining a second voltage value detected by a target voltage equalization detection channel corresponding to the target cell; determining an absolute difference between the first voltage value and the second voltage value; When it is determined that the absolute difference is greater than or equal to a preset threshold value, based on a voltage equalization detection function of a voltage equalization detection channel adjacent to the target voltage equalization detection channel, performing validity verification on the target voltage equalization detection channel; When it is determined that the validity check of the target voltage balance detection channel passes, the second voltage value detected by the target voltage balance detection channel is adopted.

2. The method for detecting cell voltage according to claim 1, characterized in that: The performing validity check on the target voltage balance detection channel includes: Determining a voltage equalization detection channel adjacent to the target voltage equalization detection channel; In the case where it is determined that a voltage balance detection function of a voltage balance detection channel adjacent to the target voltage balance detection channel is turned on, determining a third voltage value detected by the target voltage balance detection channel; Based on the third voltage value and the second voltage value, the target voltage balance detection channel is verified for validity.

3. The method for detecting cell voltage according to claim 2, characterized in that: The performing validity verification on the target voltage balance detection channel based on the third voltage value and the second voltage value includes: Determining a ratio of the third voltage value to the second voltage value; When it is determined that the ratio value is within a preset range, determining that the validity check of the target voltage balance detection channel passes; When it is determined that the ratio value is not within the preset range, it is determined that the validity check of the target voltage balance detection channel fails.

4. The method for detecting cell voltage according to any one of claims 1 to 3, characterized in that: The method further comprises: When it is determined that the validity check of the target voltage equalization detection channel fails, the first voltage value detected by the target cell voltage detection channel is adopted.

5. The method for detecting cell voltage according to any one of claims 1 to 3, characterized in that: The method further comprises: When it is determined that the absolute difference is less than the preset threshold value, the first voltage value detected by the target cell voltage detection channel is adopted.

6. A cell voltage detection circuit, characterized in that: include: A plurality of battery cell voltage detection channels and a plurality of voltage equalization detection channels, wherein the plurality of battery cell voltage detection channels and the plurality of voltage equalization detection channels have the function of detecting the voltage of the plurality of battery cells connected in series, and the plurality of battery cell voltage detection channels and the plurality of voltage equalization detection channels correspond one to one to the plurality of battery cells connected in series; the plurality of voltage equalization detection channels also have the function of detecting the voltage equalization of the plurality of battery cells connected in series; Any target voltage equalization detection channel among the plurality of voltage equalization detection channels comprises a first branch circuit and a second branch circuit; One end of the first branch circuit is connected to the negative electrode of the first battery cell, and one end of the second branch circuit is connected to the positive electrode of the first battery cell and the negative electrode of the second battery cell; the first battery cell is a battery cell corresponding to the target voltage equalization detection channel among the plurality of battery cells connected in series, and the second battery cell is a battery cell adjacent to the first battery cell; The first branch circuit and the second branch circuit each include at least one equivalent resistor connected in series, and the number of the equivalent resistors included in the first branch circuit is different from the number of the equivalent resistors included in the second branch circuit.

7. The cell voltage detection circuit according to claim 6, characterized in that: The other end of the first branch circuit and the other end of the second branch circuit are connected via a switch; When the switch is turned on, the target voltage balance detection channel has a function of detecting the voltage balance of the first battery cell.

8. The cell voltage detection circuit according to claim 6 or 7, characterized in that: Any target cell voltage detection channel among the plurality of cell voltage detection channels includes a third branch circuit and a fourth branch circuit; The third branch circuit and the fourth branch circuit each include a resistor of equal value; The third branch circuit and the fourth branch circuit are respectively connected to the positive electrode and the negative electrode of the third battery cell; the third battery cell is a battery cell corresponding to the target battery cell voltage detection channel among the plurality of battery cells connected in series.

9. The cell voltage detection circuit according to claim 6 or 7, characterized in that: The plurality of voltage equalization detection channels are numbered in sequence according to the arrangement order of the plurality of battery cells connected in series; When the number of the target voltage equalization detection channel is odd, the ratio of the number of the equivalent resistors included in the first branch circuit to the number of the equivalent resistors included in the second branch circuit is N:1; When the number of the target voltage balance detection channel is an even number, the ratio of the number of the equivalent resistors included in the first branch circuit to the number of the equivalent resistors included in the second branch circuit is 1:N; Wherein, N is a positive integer greater than or equal to 2.

10. A battery management system, characterized in that: A cell voltage detection circuit comprising the cell voltage detection circuit as described in any one of claims 6 to 9.

Images