CN106199440B - Battery management system and voltage sampling circuit and method used by same - Google Patents
Battery management system and voltage sampling circuit and method used by same Download PDFInfo
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- CN106199440B CN106199440B CN201610513608.3A CN201610513608A CN106199440B CN 106199440 B CN106199440 B CN 106199440B CN 201610513608 A CN201610513608 A CN 201610513608A CN 106199440 B CN106199440 B CN 106199440B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/25—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques
- G01R19/2503—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques for measuring voltage only, e.g. digital volt meters (DVM's)
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
- G01R31/396—Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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Abstract
The invention discloses a battery management system and a voltage sampling circuit and a voltage sampling method used by the battery management system. The battery pack managed by the battery management system comprises N batteries connected in series; the voltage sampling module of the battery management system comprises a sampling switch group and a first AD converter; the sampling switch group comprises N+1 sampling switches, the first ends of the first N sampling switches are sequentially connected with the anodes of N batteries connected in series, and the first ends of the n+1 sampling switches are connected with the cathodes of the N batteries; the second ends of the N+1 sampling switches are sequentially and alternately connected with the positive input end and the negative input end of the first AD converter; the voltage sampling module further comprises a redundant switch group; the redundant switch group comprises a first redundant switch and a second redundant switch, the first redundant switch is connected in parallel with two ends of the first sampling switch, and the second redundant switch is connected in parallel with two ends of the (n+1) th sampling switch; the processing module is used for judging whether sampling abnormal conditions exist. The invention can quickly and conveniently detect the abnormal condition of voltage sampling with low cost.
Description
[ field of technology ]
The invention relates to a battery management system and a voltage sampling circuit and a voltage sampling method used by the battery management system.
[ background Art ]
When new batteries such as lithium ion batteries are used in series, a Battery Management System (BMS) is generally required to be configured in order to ensure safe use of the batteries. The BMS is mainly used for detecting the voltages of the battery cells in the battery pack managed by the BMS in real time, and if the voltages of the battery cells in the series battery pack are not uniform, balancing is also required. As shown in fig. 1, a schematic structure of the battery management system is shown. The battery management system comprises a bidirectional DC-DC converter, a polarity reverser, a battery gating module 100, a voltage sampling module 200 and a processing module which are sequentially connected in cascade. The battery management system shown in the figure manages for 4 strings of battery packs. The voltage sampling module 200 includes 5 sampling switches and a first AD converter. The balancing function of the battery management system is a function of the BMS to make the voltages and capacities of the individual cells in the battery pack consistent with each other and to make the charge and discharge characteristics of the individual cells consistent with each other.
In normal operation, the CPU sequentially controls the sampling switches S1 to S5 (S1 to S5 are typically high-speed signal electronic switches), sequentially selects each battery to the input port of the first AD converter, and after AD conversion, the CPU can sequentially obtain the voltage parameter of each battery. If the CPU finds that the voltage of one battery is inconsistent with the voltage of other battery monomers through comparison, the CPU controls the gating switches K1-K5 (the K1-K5 are generally high-current power switches) to be closed, the battery monomers with inconsistent voltages are connected to the commutator (the polarity of the odd and even voltages is opposite, so that polarity reversing is needed), the battery monomers with inconsistent voltages are connected to the bidirectional DC-DC after passing through the commutator, and the CPU controls the bidirectional DC-DC to charge or discharge the battery. During the equalization process, the CPU continuously monitors the cell voltage through the voltage sampling module 200 and stops equalization once the voltage is found to be up to the desired level.
To sum up, to make the balancing function of the BMS work accurately, the accuracy of the voltage sampling module 200 to sample the cell voltage is critical to the BMS. For important signals, the most common methods described in the international standard for functional safety of automotive electronics and electrical systems ISO26262 are: the redundancy backup sampling method is to sample a single important signal by adopting 2 circuits with the same function, and increase redundancy judgment of sampling voltage. As shown in fig. 2, a schematic circuit structure for adding a redundant voltage acquisition function is shown. An independent circuit is added in the figure, comprising switches S11, S21, S31, S41, S51 and an AD converter, which detects the cell voltage. The correctness of single voltage detection is ensured by the two sets of circuits through mutual verification. And only when the difference value of the collection values of the 2 sets of circuits to the same single voltage is within a certain range, the active equalization battery management is started, so that the error equalization battery management caused by single voltage collection errors is greatly reduced, and the safe and reliable management of the BMS is further improved. However, this scheme increases the number of switches by a multiple, and the circuit is complicated. Particularly, when a large number of battery packs, such as 60 battery strings, are managed, one set of sampling needs 61 switch assemblies, and two sets of sampling needs 122 switch assemblies, so that the circuit connection is too complex, and the cost of the whole battery management system is high.
[ invention ]
The technical problems to be solved by the invention are as follows: the defects of the prior art are overcome, and a battery management system, a voltage sampling circuit and a voltage sampling method used by the battery management system are provided, so that abnormal voltage sampling conditions can be detected quickly and conveniently with low cost.
The technical problems of the invention are solved by the following technical scheme:
a battery management system comprises a bidirectional DC-DC converter, a polarity reverser, a battery gating module, a voltage sampling module and a processing module which are sequentially connected in cascade; the battery pack managed by the battery management system comprises N batteries connected in series; the voltage sampling module comprises a sampling switch group and a first AD converter; the sampling switch group comprises N+1 sampling switches, the first ends of the first N sampling switches are sequentially connected with the anodes of N batteries connected in series, and the first ends of the n+1 sampling switches are connected with the cathodes of the N batteries; the second ends of the N+1 sampling switches are sequentially and alternately connected with the positive input end and the negative input end of the first AD converter; the output end of the first AD converter is connected with a first AD port of the processing module; the voltage sampling module further comprises a redundant switch group; the redundant switch group comprises a first redundant switch and a second redundant switch, the first redundant switch is connected in parallel with two ends of a first sampling switch, and the second redundant switch is connected in parallel with two ends of an (n+1) th sampling switch; the processing module is used for detecting the voltage of the battery under the conduction of the N+1 sampling switches, detecting the voltage of the battery under the conduction of the two redundant switches matched with the even sampling switches, and judging whether the abnormal sampling condition exists or not by comparing whether the difference value of the corresponding voltages exceeds a set threshold value.
A voltage sampling circuit for a battery management system includes a sampling switch group and a first AD converter; the sampling switch group comprises N+1 sampling switches, the first ends of the first N sampling switches are used for sequentially connecting the anodes of N batteries connected in series in the battery group managed by the battery management system, and the first ends of the n+1 sampling switches are connected with the cathodes of the N batteries; the second ends of the n+1 sampling switches are used for sequentially and alternately connecting the positive input end and the negative input end of a first AD converter in the battery management system; the output end of the first AD converter is used for being connected with a first AD port of a processing module in the battery management system; the voltage sampling circuit further comprises a redundancy switch group, the redundancy switch group comprises a first redundancy switch and a second redundancy switch, the first redundancy switch is connected in parallel to two ends of the first sampling switch, and the second redundancy switch is connected in parallel to two ends of the (n+1) th sampling switch.
The voltage sampling method for the battery management system comprises a bidirectional DC-DC converter, a polarity reverser, a battery gating module, a voltage sampling module and a processing module which are sequentially connected in cascade; the battery pack managed by the battery management system comprises N batteries connected in series; the voltage sampling module comprises a sampling switch group and a first AD converter; the sampling switch group comprises N+1 sampling switches, the first ends of the first N sampling switches are sequentially connected with the anodes of N batteries connected in series, and the first ends of the n+1 sampling switches are connected with the cathodes of the N batteries; the second ends of the N+1 sampling switches are sequentially and alternately connected with the positive input end and the negative input end of the first AD converter; the output end of the first AD converter is connected with a first AD port of the processing module; the voltage sampling method comprises the following steps: 1) The two ends of the first sampling switch are connected with a first redundant switch in parallel, and the two ends of the (n+1) th sampling switch are connected with a second redundant switch in parallel; 2) Detecting the voltage of the battery under the conduction of the N+1 sampling switches, detecting the voltage of the battery under the conduction of the two redundant switches matched with the even sampling switches, and judging whether the abnormal sampling condition exists or not by comparing whether the difference value of the corresponding voltages exceeds a set threshold value.
Compared with the prior art, the invention has the beneficial effects that:
the voltage sampling circuit used in the battery management system can achieve redundancy detection of single voltage sampling by only adding two redundancy switches and corresponding comparison strategies through the processing module in the battery management system on the basis of the existing sampling circuit. When the voltage difference value is found to exceed the set threshold value after comparison, the abnormal sampling condition can be rapidly judged, and the condition of inaccurate sampling can be rapidly found. Only when the two compared voltage acquisition values are close, the difference value is in a certain range, active equalization battery management can be started, error equalization battery management caused by single voltage acquisition errors is greatly reduced, and BMS safe and reliable management is further improved. The circuit structure of the voltage sampling circuit is simple and practical, and has the advantages of high cost performance, capability of saving PCB space and the like.
[ description of the drawings ]
Fig. 1 is a schematic diagram of a prior art battery management system;
FIG. 2 is a schematic diagram of a prior art battery management system with a redundant voltage acquisition function added thereto;
fig. 3 is a schematic view illustrating a structure of a battery management system according to a first embodiment of the present invention;
fig. 4 is a schematic structural diagram of a battery management system according to a second embodiment of the present invention.
[ detailed description ] of the invention
The invention will be described in further detail with reference to the following detailed description and with reference to the accompanying drawings.
Detailed description of the preferred embodiments
As shown in fig. 3, the battery management system of this embodiment includes a bidirectional DC-DC converter, a polarity converter, a battery gating module 100, a voltage sampling module 200, and a processing module, which are sequentially cascade-connected. The battery pack managed by the battery management system includes 4 series-connected batteries B1, B2, B3, and B4. The voltage sampling module 200 includes a sampling switch group and a first AD converter 201. The sampling switch group comprises 5 sampling switches S1, S2, S3, S4 and S5, the first ends of the sampling switches S1, S2, S3 and S4 are sequentially connected with the anodes of N batteries connected in series, and the first end of the sampling switch S5 is connected with the cathode of the 4 th battery B4. The second ends of the sampling switches S1, S2, S3, S4 and S5 are sequentially and alternately connected to the positive input end and the negative input end of the first AD converter. An output terminal of the first AD converter 201 is connected to a first AD port of the processing module.
The voltage sampling module 200 also includes a redundant set of switches. The redundancy switch group includes a first redundancy switch P1 and a second redundancy switch P2. The first redundancy switch P1 is connected in parallel to two ends of the first sampling switch S1, and the second redundancy switch P2 is connected in parallel to two ends of the fifth sampling switch S5. The processing module is used for detecting the voltage of the battery under the conduction of the 5 sampling switches, detecting the voltage of the battery under the conduction of the two redundant switches matched with the even sampling switches, and judging whether the abnormal sampling condition exists or not by comparing whether the difference value of the corresponding voltages exceeds a set threshold value.
When two adjacent sampling switches are conducted, the CPU detects and obtains first sampling voltages of the batteries respectively. In particular, the method comprises the steps of,
and controlling to conduct the first sampling switch S1 and the second sampling switch S2, sampling the voltage of the 1 st string of single batteries B1, and entering a CPU after AD sampling to obtain a first sampling voltage V1 of the single batteries B1.
And controlling to conduct the second sampling switch S2 and the third sampling switch S3, sampling the voltage of the series-2 single battery B2, and entering the CPU after AD sampling to obtain a first sampling voltage V2 of the single battery B2.
And controlling to conduct the third sampling switch S3 and the fourth sampling switch S4, sampling the voltage of the 3 rd string of single batteries B3, and enabling the voltage to enter a CPU after AD sampling to obtain a first sampling voltage V3 of the single batteries B3.
And controlling to conduct the fourth sampling switch S4 and the fifth sampling switch S5, sampling the voltage of the 4 th string of single batteries B4, and enabling the sampled voltage to enter a CPU (Central processing Unit) after AD (analog-to-digital) sampling to obtain a first sampling voltage V4 of the single batteries B4.
The first set of voltage samples for each cell is obtained above.
When the two redundant switches P1, P2 are turned on in cooperation with the even number of sampling switches S2, S4, the CPU detects the sampling voltages of the first battery and the nth battery and the sum of the voltages of the plurality of adjacent batteries, respectively. In particular, the method comprises the steps of,
and controlling to conduct the first redundant switch P1 and the second sampling switch S2, sampling the voltage of the 1 st string of single batteries B1, and entering a CPU after AD sampling to obtain a second sampling voltage V11 of the single batteries B1.
And controlling to conduct the first redundant switch P1 and the fourth sampling switch S4, and entering the CPU after AD sampling to obtain the sum V123 of the voltages of the 1,2, 3-th single batteries B1, B2 and B3.
And controlling to conduct the second sampling switch S2 and the second redundant switch P2, and entering the CPU after AD sampling to obtain the sum V234 of the voltages of the 2,3,4 th strings of single batteries B2, B3 and B4.
And controlling to conduct the fourth sampling switch S4 and the second redundant switch P2, sampling the voltage of the 4 th string of single batteries B4, and entering the CPU after AD sampling to obtain a second sampling voltage V41 of the single batteries B4.
And obtaining another group of voltage sampling values.
After detecting the two groups of voltages, the CPU compares whether the difference value of the corresponding voltages exceeds a set threshold value to judge whether the abnormal sampling condition exists.
Δ1＝V11-V1
Δ2＝V1+V2+V3-V123
Δ3＝V2+V3+V4-V234
Δ4＝V41-V4
If the voltage difference between the two sets of samples is within the allowable error range (for example, 10 mv), the samples can be considered as normal. If the set threshold is exceeded, sampling anomalies are necessarily present.
In the course of the actual use process, the water-soluble fiber,
if the delta 1 is within the error allowable range, the two acquired voltages of the B1 are indicated to be close, and the acquired voltages are the actual voltages corresponding to the B1, so that the acquisition is accurate; if Δ1 exceeds the error allowable range, it indicates that one or both of the two voltage acquisitions are inaccurate, indicating that the voltage acquisition of B1 is abnormal. At this time, it can be directly judged that the acquisition abnormality exists on the B1 battery.
If Δ2 exceeds the error allowable range, any one of V1, V2, V3 and V123 is inaccurate because Δ2=v1+v2+v3-V123, and Δ2 is out of range, and any one of the corresponding switch faults will cause abnormal sampling. Therefore, if Δ2 exceeds the standard, an abnormal situation is necessarily present. At this time, the CPU does not start the equalization function so as to avoid the occurrence of error equalization operation. In this case, the voltage acquisition module 200 can only acquire and determine that there is an abnormality, but cannot determine which single battery has an abnormality in sampling, and if it needs to be determined, it needs to cooperate with the subsequent corresponding detection measures to perform detection. However, before further detection, the voltage acquisition module of the embodiment can determine that an abnormal condition exists in voltage acquisition in advance, and lock the abnormal condition on batteries corresponding to a plurality of switches in a small range.
Similarly, if Δ3 exceeds the allowable error range, the abnormal condition is necessarily present, the abnormal acquisition condition can be determined in advance, although the abnormal sampling of which section of single battery can be determined by combining the subsequent corresponding detection measures, the abnormal condition of voltage acquisition can be determined in advance, and the abnormal condition can be locked on the batteries corresponding to the switches in a small range.
If delta 4 is within the error allowable range, the two acquired voltages of B4 are indicated to be close, the acquired voltages are the actual voltages corresponding to B4, and the acquisition is accurate; if delta 4 exceeds the error allowable range, one or two of the two acquired voltages are inaccurate, and the voltage acquisition of B4 is abnormal. At this time, it can be directly judged that the acquisition abnormality exists on the B4 battery.
By analogy, when more batteries exist, two redundant switches are additionally arranged, and the voltage sum of the voltages of the corresponding first and second single batteries and the voltages of the middle multiple voltages is detected by matching with the conduction of the even sampling switch. By comparing whether the voltage difference is within a threshold range, it is quickly determined whether an abnormal condition exists. The above voltage acquisition scheme can be applied to 4-string battery packs, 12-string battery packs, 24-string battery packs, 36-string battery packs, 48-string battery packs or 60-string battery packs which are commonly used in the market at present.
In summary, in this embodiment, the first redundant switch and the second redundant switch form a redundant switch set, and the abnormal situation can be rapidly determined only by adding two additional switches. Particularly, when the collection of the battery packs is accurately checked in a large scale, two switches are additionally arranged in each battery management system, so that the abnormal sampling of the battery packs in the battery management systems can be quickly determined, and the redundant switch is not required to be arranged for detecting each single battery in the battery packs in each battery management system as in the past. The abnormal condition of voltage acquisition can be detected rapidly and simply.
Based on the above voltage acquisition scheme, the present embodiment further provides a dynamic balancing method of a battery management system, which includes the following steps:
step 1: the conduction sequence of the sampling switch is adjusted by embedded control software, and the voltage of each single cell in each group of sequentially connected battery packs is detected.
Step 2: the conduction sequence of the redundant switch and the even sampling switch is adjusted by the embedded control software, and the voltage of the corresponding battery or the sum of the voltages of the corresponding batteries is detected to obtain the other redundant set of individual voltage.
And (3) comparing the monomer voltages acquired in the step (1) and the step (2) by the CPU, and if the difference of the voltages in the group (2) is found to be larger than the set threshold value, carrying out alarm voltage acquisition error and abnormal alarm at the moment, and not starting the dynamic equalization process in the step (3) and the step (4). If the voltage difference of the 2 groups is smaller than or equal to the set threshold value, the step 3 and the step 4 are carried out, and the balanced battery management is started. And if the set threshold value is exceeded and the acquisition is abnormal, alarming is carried out. And after the acquisition of which battery is abnormal is identified later, correspondingly replacing the acquired switch.
Step 3: the CPU judges the bit number of the single battery which needs to be charged or discharged singly and has too low or too high voltage.
Step 4: the CPU sends out control command to control the corresponding polarity selection switch group to switch the collecting bus to perform polarity conversion, and simultaneously control the corresponding battery selection switch group to perform polarity matching, and control the working direction of the bidirectional isolation converter, and the single battery with too low or too high voltage required to be charged and discharged independently is connected to the collecting bus to charge or discharge, so that energy transfer is realized.
Step 5: repeating the steps 1) to 3) until the voltages of the single batteries in the battery packs which are sequentially connected in series are within the set allowable error range, and achieving dynamic balance.
In this embodiment, the selection and function of the device are described as follows:
1) The sampling switches S1-S5 are high-speed signal electronic switches
In practical application, the number can be far more than 5 according to specific application, and the device is a high-voltage-resistant solid relay. The specific function of the high-speed signal electronic sampling switches S1-S5 in the circuit is to switch the battery cells needing to collect channels. The characteristics are that: long service life, high voltage endurance and high switching speed.
2) The AD converter is a high-precision precise operational amplifier conditioning circuit.
The specific function of the AD converter in the circuit is to condition and convert the switched collected voltage into the voltage which can be collected by the CPU. The voltage range that the CPU can collect here is 0-3.3 vdc.
3) The added redundant switches P1 and P2 are high-speed signal electronic switches, and the device model is a high-voltage-resistant solid relay.
4) The CPU is not limited to MCU or DSP, ARM, etc. .
The specific function of the CPU in the circuit is to collect two groups of redundant single voltage values, compare the differences and judge whether the collection abnormality exists. In addition, the CPU is also used for dynamic equalization in the battery management system, determining the position number of the highest single battery and the position number of the lowest single battery, controlling the discharge of the highest single battery, charging the lowest single battery, and enabling the single battery voltage to be consistent through high-efficiency energy transfer and making up the difference of the batteries.
Detailed description of the preferred embodiments
The present embodiment differs from the first embodiment in that: in this embodiment, the voltage sampling module further includes a second AD converter, so as to implement redundancy setting of the AD converter.
As shown in fig. 4, the battery management system of this embodiment includes a bidirectional DC-DC converter, a polarity converter, a battery gating module 100, a voltage sampling module 200, and a processing module, which are sequentially cascade-connected. In the battery management system, the voltage sampling module 200 includes a sampling switch group and a first AD converter 201. The composition of the sampling switch group, the connection to the first AD converter, and the like are the same as those of the first embodiment, and are not repeated here. The difference is that the voltage sampling module 200 further includes a second AD converter 202, where a positive input end and a negative input end of the second AD converter 202 are respectively connected to the positive input end and the negative input end of the first AD converter 201, and an output end of the second AD converter 202 is connected to a second AD port of the processing module CPU. Thus, the redundant channel reaches the CPU through another group of AD converters, and the other path of AD channel of the CPU is utilized.
In operation, there are two embodiments:
first embodiment: when two adjacent sampling switches are turned on, the first sampling voltage of each battery passes through the first AD converter 201 to reach the CPU, the CPU detects the voltage value at the first AD port, and the first group of voltage sampling values V1, V2, V3 and V4 of each single battery are acquired. The specific switch turn-on conditions and corresponding voltages are the same as in the first embodiment and are not repeated here. When the two redundant switches P1 and P2 are turned on in cooperation with the even sampling switches S2 and S4, the sum of the sampled voltages of the first battery and the nth battery and the voltages of the plurality of adjacent batteries reaches the CPU through the second AD converter 202, the CPU detects the voltage value at the second AD port, and the second set of voltage sampled data V11, V123, V234 and V41 is acquired. The specific switch turn-on coordination and corresponding voltages are not repeated here as in the first embodiment. In this way, by redundancy backup of the second AD converter 202, the situation of sampling abnormality caused by the failure of the first AD converter 201 can be avoided, and the abnormal failure position can be accurately located.
Second embodiment: when two adjacent sampling switches are turned on, the first sampling voltage of each battery passes through the second AD converter 202 to reach the CPU, the CPU detects the voltage value at the second AD port, and the first group of voltage sampling values V1, V2, V3 and V4 of each single battery are acquired. When the two redundant switches P1 and P2 are turned on in cooperation with the even sampling switches S2 and S4, the sum of the sampled voltages of the first battery and the nth battery and the voltages of the plurality of adjacent batteries reaches the CPU through the first AD converter 201, the CPU detects the voltage value at the first AD port, and the second set of voltage sampled data V11, V123, V234 and V41 is acquired. Thus, with this embodiment, by redundancy backup of the second AD converter 202, the situation of sampling abnormality caused by the failure of the first AD converter 201 can be avoided, and the abnormal failure position can be accurately located.
Preferably, the two schemes are implemented synchronously, resulting in 4 different sets of sampled data. If the corresponding difference of the 4 groups of sampling data is within a reasonable error range, the sampling is accurate. At this time, the equalization control function is started for the charge and discharge of the too high or too low battery, so that the accuracy of the equalization control is greatly improved, and the false equalization action caused by the fault of the AD converter is avoided.
In the present embodiment, as in the first embodiment, the abnormal situation can be rapidly determined by newly adding two switches. The method is particularly suitable for mass inspection of whether the collection of the battery packs is accurate or not and for management collection of the battery packs with more strings. The abnormal condition of voltage acquisition can be detected rapidly and simply. In addition, through the backup of the second AD converter, the error equalization action caused by the fault of the AD converter can be avoided, and the accuracy of equalization control is greatly improved.
The foregoing is a further detailed description of the invention in connection with the preferred embodiments, and it is not intended that the invention be limited to the specific embodiments described. Several substitutions and obvious modifications will occur to those skilled in the art without departing from the spirit of the invention, and the same is to be considered to be within the scope of the invention.
Claims (10)
1. A battery management system comprises a bidirectional DC-DC converter, a polarity reverser, a battery gating module, a voltage sampling module and a processing module which are sequentially connected in cascade; the battery pack managed by the battery management system comprises N batteries connected in series; the voltage sampling module comprises a sampling switch group and a first AD converter; the sampling switch group comprises N+1 sampling switches, the first ends of the first N sampling switches are sequentially connected with the anodes of N batteries connected in series, and the first ends of the n+1 sampling switches are connected with the cathodes of the N batteries; the second ends of the N+1 sampling switches are sequentially and alternately connected with the positive input end and the negative input end of the first AD converter; the output end of the first AD converter is connected with a first AD port of the processing module; the method is characterized in that: the voltage sampling module further comprises a redundant switch group; the redundant switch group comprises a first redundant switch and a second redundant switch, the first redundant switch is connected in parallel with two ends of a first sampling switch, and the second redundant switch is connected in parallel with two ends of an (n+1) th sampling switch; the processing module is used for detecting the voltage of the battery under the conduction of the N+1 sampling switches and detecting the voltage of a single battery or the sum of the voltages of a plurality of adjacent batteries under the conduction of the even sampling switches in the N+1 sampling switches respectively matched with the two redundant switches, and judging whether the abnormal sampling condition exists or not by comparing whether the difference value of the corresponding voltages exceeds a set threshold value.
2. The battery management system according to claim 1, wherein: the processing module is used for detecting the voltage of each battery at the first AD port under the conduction of the N+1 sampling switches, detecting the voltage of one battery or the sum of a plurality of battery voltages at the first AD port under the conduction of the two redundant switches matched with the even sampling switches, and judging whether the abnormal sampling condition exists or not by comparing whether the difference value of the corresponding voltages exceeds a set threshold value.
3. The battery management system according to claim 1, wherein: the voltage sampling module further comprises a second AD converter, the positive input end and the negative input end of the second AD converter are respectively connected with the positive input end and the negative input end of the first AD converter, and the output end of the second AD converter is connected with the second AD port of the processing module.
4. A battery management system according to claim 3, wherein: the processing module is used for detecting the voltage of each battery at the first AD port under the conduction of the N+1 sampling switches, detecting the voltage of one battery or the sum of a plurality of battery voltages at the second AD port under the conduction of the two redundant switches matched with the even sampling switches, and judging whether the abnormal sampling condition exists or not by comparing whether the difference value of the corresponding voltages exceeds a set threshold value.
5. A battery management system according to claim 3, wherein: the processing module is used for detecting the voltage of each battery at the second AD port under the conduction of the N+1 sampling switches, detecting the voltage of one battery or the sum of the voltages of a plurality of batteries at the first AD port under the conduction of the two redundant switches matched with the even sampling switches, and judging whether the abnormal sampling condition exists or not by comparing whether the difference value of the corresponding voltages exceeds a set threshold value.
6. A voltage sampling circuit for a battery management system, characterized by: the device comprises a sampling switch group and a first AD converter; the sampling switch group comprises N+1 sampling switches, the first ends of the first N sampling switches are used for sequentially connecting the anodes of N batteries connected in series in the battery group managed by the battery management system, and the first ends of the n+1 sampling switches are connected with the cathodes of the N batteries; the second ends of the n+1 sampling switches are used for sequentially and alternately connecting the positive input end and the negative input end of a first AD converter in the battery management system; the output end of the first AD converter is used for being connected with a first AD port of a processing module in the battery management system; the voltage sampling circuit further comprises a redundancy switch group, the redundancy switch group comprises a first redundancy switch and a second redundancy switch, the first redundancy switch is connected in parallel to two ends of the first sampling switch, the second redundancy switch is connected in parallel to two ends of the (N+1) th sampling switch, wherein the two redundancy switches are respectively matched with the (even) th sampling switch in the (N+1) th sampling switch to be conducted so as to detect the voltage of a single battery or the sum of voltages of a plurality of adjacent batteries, and whether sampling abnormal conditions exist or not is judged by comparing whether the difference value of the corresponding voltages detected under the conduction of the (N+1) th sampling switch exceeds a set threshold value.
7. The voltage sampling method for the battery management system comprises a bidirectional DC-DC converter, a polarity reverser, a battery gating module, a voltage sampling module and a processing module which are sequentially connected in cascade; the battery pack managed by the battery management system comprises N batteries connected in series; the voltage sampling module comprises a sampling switch group and a first AD converter; the sampling switch group comprises N+1 sampling switches, the first ends of the first N sampling switches are sequentially connected with the anodes of N batteries connected in series, and the first ends of the n+1 sampling switches are connected with the cathodes of the N batteries; the second ends of the N+1 sampling switches are sequentially and alternately connected with the positive input end and the negative input end of the first AD converter; the output end of the first AD converter is connected with a first AD port of the processing module; the method is characterized in that: the voltage sampling method comprises the following steps: 1) The two ends of the first sampling switch are connected with a first redundant switch in parallel, and the two ends of the (n+1) th sampling switch are connected with a second redundant switch in parallel; 2) Detecting the voltage of a battery under the conduction of N+1 sampling switches, detecting the voltage of a single battery or the sum of voltages of a plurality of adjacent batteries under the conduction of an even sampling switch in the N+1 sampling switches respectively matched with two redundant switches, and judging whether the abnormal sampling condition exists or not by comparing whether the difference value of the corresponding voltages exceeds a set threshold value.
8. The voltage sampling method of claim 7, wherein: and 2) detecting the voltage of each battery at the first AD port under the conduction of the N+1 sampling switches, detecting the voltage of one battery or the sum of the voltages of a plurality of batteries at the first AD port under the conduction of the two redundant switches and the even sampling switches, and judging whether the abnormal sampling condition exists or not by comparing whether the difference value of the corresponding voltages exceeds a set threshold value.
9. The voltage sampling method of claim 7, wherein: the step 1) further comprises the step of arranging a second AD converter in a redundant manner between the voltage sampling module and a second AD port of the processing module; and 2) detecting the voltage of each battery at the first AD port under the conduction of the N+1 sampling switches, detecting the voltage of one battery or the sum of the voltages of a plurality of batteries at the second AD port under the conduction of the two redundant switches and the even sampling switches, and judging whether the abnormal sampling condition exists or not by comparing whether the difference value of the corresponding voltages exceeds a set threshold value.
10. The voltage sampling method of claim 7, wherein: the step 1) further comprises the step of arranging a second AD converter in a redundant manner between the voltage sampling module and a second AD port of the processing module; and 2) detecting the voltage of each battery at the second AD port under the conduction of the N+1 sampling switches, detecting the voltage of one battery or the sum of the voltages of a plurality of batteries at the first AD port under the conduction of the two redundant switches and the even sampling switches, and judging whether the abnormal sampling condition exists or not by comparing whether the difference value of the corresponding voltages exceeds a set threshold value.
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