CN109683098B - Current detection system for power battery system - Google Patents
Current detection system for power battery system Download PDFInfo
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- CN109683098B CN109683098B CN201811558011.6A CN201811558011A CN109683098B CN 109683098 B CN109683098 B CN 109683098B CN 201811558011 A CN201811558011 A CN 201811558011A CN 109683098 B CN109683098 B CN 109683098B
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Abstract
The invention relates to the technical field of power battery systems, in particular to a current detection system for a power battery system, which comprises a battery management system chip, wherein the battery management system chip comprises a comparator circuit, a data selector circuit and an analog-to-digital converter, and the positive and negative of an output signal are determined by comparing a positive phase input end signal and a negative phase input end signal of the comparator circuit, so that the gating of the data selector circuit is controlled, the input differential mode signal of the analog-to-digital converter is ensured to be positive, and the signal input range requirement of the analog-to-digital converter can be met. The beneficial effects of the technical scheme are as follows: in the whole power battery system, a voltage detection chip can be omitted, and the detection of functions such as voltage, current and the like by a single power battery management chip is realized.
Description
Technical Field
The invention relates to the technical field of power battery systems, in particular to a current detection system for a power battery system.
Background
With the popularization and use of new energy automobiles, people have higher and higher technical requirements on the new energy automobiles. At present, in an electric vehicle, a Battery Management System (BMS) accounts for more than about 30% of the cost, and therefore, an automobile factory is particularly interested in improving the technology for producing power batteries in the BMS. An efficient BMS system means that the car can have a longer range, whereas in a BMS system the battery typically has several parameters: voltage, battery capacity, energy density, SOC (State Of Charge, also called residual capacity), internal resistance, lifetime, and the like.
In an electric automobile, a battery pack in a BMS realizes high voltage and large capacity by connecting single batteries in series and in parallel, so that the consistency of the single batteries also becomes a parameter. The internal structure and material of the single battery can be different due to the inconsistent processes in the manufacturing process, so that the difference exists. The BMS chip detects the state of the single battery, and the main controller performs a corresponding operation (e.g., battery equalization) according to the collected state. The SOC is defined as the ratio of the residual capacity to the battery capacity, is used for representing the residual capacity of the power battery, accurately estimates the SOC, and is a key link for improving the driving mileage of the electric vehicle and prolonging the service life of the battery.
In a power battery system, the current methods for measuring the current of the power battery system mainly comprise: shunt method, hall sensor method, etc. In view of the existing solutions, current collection requires additional components (such as hall sensors or voltage detection chips), which increases the cost and complicates the calibration process, a new current detection technology for power battery systems is required.
Disclosure of Invention
In view of the above-mentioned deficiencies of the prior art, the present invention provides a current sensing system for a power battery system.
The specific technical scheme is as follows:
a current sensing system for a power battery system, comprising:
a battery management system chip, the battery management system chip comprising:
the positive phase input end of the comparator circuit is connected with the first pin of the battery management system chip, the negative phase input end of the comparator circuit is connected with the second pin of the battery management system chip, and the positive and negative of a signal output by the comparator circuit is determined by comparing the positive phase input signal with the negative phase input signal;
the data selector circuit comprises a first data selector and a second data selector, a first pin of the battery management system chip is respectively connected with a first signal end of the first data selector and a second signal end of the second data selector, and a second pin of the battery management system chip is respectively connected with a second signal end of the first data selector and a first signal end of the second data selector;
the input end of the analog-to-digital converter is connected with the output end of the data selector circuit and used for converting the analog signal input by the data selector circuit into a digital signal and outputting the digital signal;
the output end of the analog-to-digital converter is connected with the input end of a micro control processor and used for sending the digital signal output by the analog-to-digital converter to the micro control processor for analysis and processing and monitoring and managing the current.
Further, the positive and negative of the signal output by the comparator circuit are output by comparing:
when the signal of the positive phase input end is greater than the signal of the negative phase input end, the signal output by the comparator circuit is positive;
when the signal of the positive phase input end is smaller than the signal of the negative phase input end, the signal output by the comparator circuit is negative.
Further, the signal output by the comparator circuit is used for controlling the gating of the data selector circuit.
Further, the output end of the first data selector is connected with the first input end of the analog-to-digital converter; the output end of the second data selector is connected with the second input end of the analog-to-digital converter.
Further, when the power battery system is in a discharging state, the signal output by the comparator circuit is positive, and the first signal end of the first data selector and the first signal end of the second data selector are gated;
when the power battery system is in a charging state, the signal output by the comparator circuit is negative, and the second signal end of the first data selector and the second signal end of the second data selector are gated.
Further, the current detection system further includes a shunt connected between the first pin of the battery management system chip and the second pin of the battery management system chip.
Further, the first data selector and the second data selector include an enabling terminal for turning on and off the first data selector and the second data selector.
Further, when the enable terminal signal is 1, the first data selector and the second data selector are switched on;
when the enable signal is 0, the first data selector and the second data selector are disconnected.
The technical scheme of the invention has the beneficial effects that:
the gating of the data selector is controlled through the output end of the comparator, the input differential mode signal of the analog-to-digital converter is ensured to be positive, the signal input range requirement of the analog-to-digital converter can be met, a voltage detection chip can be omitted in the whole power battery system, and the single power battery management chip can complete the detection of functions such as voltage, current and the like.
Drawings
FIG. 1 is a functional block diagram of a current sensing system for a power battery system according to an embodiment of the present invention;
FIG. 2a is a circuit diagram of a comparator of a battery management system chip according to an embodiment of the present invention;
FIG. 2b is a circuit diagram of a data selector and an analog-to-digital converter of a battery management system chip according to an embodiment of the present invention;
FIG. 3 is a circuit diagram of a signal path when the power battery system of the embodiment of the present invention is in a discharging state;
FIG. 4 is a circuit diagram illustrating signal paths when the power battery system of the present embodiment is in a charging state.
In the drawings: 1. a comparator circuit; 2. a data selector circuit; 3. an analog-to-digital converter; 4. a first pin of a battery management system chip; 5. a second pin of the battery management system chip; 6. flow divider
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
The present invention will be further described with reference to the accompanying fig. 1 to 4 and the specific embodiments, but the present invention is not limited thereto.
As shown in fig. 1, fig. 2a and fig. 2b, a current detection system for a power battery system includes:
a battery management system chip, the battery management system chip comprising:
the positive phase input end of the comparator circuit is connected with a first pin 4 of the battery management system chip, the negative phase input end of the comparator circuit is connected with a second pin 5 of the battery management system chip, and the positive and negative of a signal VOUT output by the comparator circuit is determined by comparing the positive phase input signal with the negative phase input signal;
a data selector circuit 2, the data selector circuit includes a first data selector M1 and a second data selector M2, a first pin 4 of the battery management system chip is connected to a first signal terminal S1 of the first data selector M1 and a second signal terminal S2 of the second data selector M2, respectively, and a second pin 5 of the battery management system chip is connected to a second signal terminal S2 of the first data selector M1 and a first signal terminal S1 of the second data selector M2, respectively;
an analog-to-digital converter 3, the input ends X1, X2 of the analog-to-digital converter are connected with the output end D of the data selector circuit, for converting the analog signal input by the data selector circuit into a digital signal and outputting the digital signal;
the output end ADC OUT of the analog-to-digital converter 3 is connected to the input end of a micro control processor MCU, and is used to transmit the digital signal output by the analog-to-digital converter 3 to the micro control processor MCU for analysis and processing, and monitor and manage the current.
According to the technical scheme, Ic represents charging current, Id represents discharging current, BAT + is positive output of a battery pack, BAT-is negative output of the battery pack, the equivalent of the shunt 6 is a low-pass filter consisting of resistors R, Rf and Cf, positive and negative output signals are determined by comparing a positive input end signal and a negative input end signal of the comparator circuit 1 in the battery management system chip, gating of the data selector circuit 2 is controlled, and the differential mode signal input by the analog-to-digital converter 3 is ensured to be positive, so that the signal input range requirement of the analog-to-digital converter 3 can be met, communication between a single battery management system chip and a microcontroller MCU can be realized, and monitoring and management of the whole power battery system are completed.
As a preferred embodiment, in the comparator circuit 1:
when the signal of the positive phase input end is greater than the signal of the negative phase input end, the signal output by the comparator circuit is positive;
when the signal of the positive phase input end is smaller than the signal of the negative phase input end, the signal output by the comparator circuit is negative;
according to the technical scheme, the gating of the data selector circuit 2 is determined by comparing the magnitude of the positive input end signal and the magnitude of the negative input end signal, so that the input differential mode signal of the analog-to-digital converter 3 is ensured to be positive, and the management of a power battery management system is met.
As a preferred embodiment, the signal of VOUT output from the comparator circuit is used to control the gating of the data selector circuit 2;
the output terminal D VIN + of the first data selector M1 is connected to the first input terminal X1 of the analog-to-digital converter; the output terminal D VIN of the second data selector M2 is connected to the second input terminal X2 of the analog-to-digital converter;
when the power battery system is in a discharging state, the signal output VOUT by the comparator circuit is positive, and the first signal end S1 of the first data selector and the first signal end S1 of the second data selector are gated;
when the power battery system is in the charging state, the signal output by the comparator circuit is negative, gating the second signal terminal S2 of the first data selector M1 and the second signal terminal S2 of the second data selector M2.
In the above technical solution, the signal output VOUT by the comparator circuit is used to control the gating of the data selector circuit 2, when the power battery system is in the discharging state, the output signal is positive, the signal gates the first signal terminal S1 of the first data selector M1 and the first signal terminal S1 of the second data selector M2, and the signal path is as shown in fig. 3; when the power battery system is in a charging state, the output signal is negative, the signal gates the second signal end S2 of the first data selector M1 and the second signal end S2 of the second data selector M2, and the signal path is as shown in FIG. 4, so that the real-time accurate monitoring and management of the whole power battery system are ensured.
As a preferred embodiment, the current detection system further includes a shunt 6 connected between the first pin 4 of the battery management system chip and the second pin 5 of the battery management system chip for measuring the direct current at the two ends to ensure the normal operation of the battery management system chip.
In a preferred embodiment, the first data selector M1 and the second data selector M2 include an enable terminal ENB for turning on/off the first data selector M1 and the second data selector M2;
when the enable terminal signal is 1, the first data selector M1 and the second data selector M2 are turned on;
when the enable terminal signal is 0, the first and second data selectors M1 and M2 are turned off.
According to the technical scheme, the enable end ENB controls the on-off of the first data selector M1 and the second data selector M2, so that the normal work of a chip is guaranteed, and the management and monitoring of the whole power battery system are facilitated.
While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.
Claims (7)
1. A current sensing system for a power battery system, comprising:
a battery management system chip, the battery management system chip comprising:
the positive phase input end of the comparator circuit is connected with the first pin of the battery management system chip, the negative phase input end of the comparator circuit is connected with the second pin of the battery management system chip, and the positive and negative of the signal output by the comparator circuit is determined by comparing the magnitude of the positive phase input signal and the negative phase input signal;
the data selector circuit comprises a first data selector and a second data selector, a first pin of the battery management system chip is respectively connected with a first signal end of the first data selector and a second signal end of the second data selector, and a second pin of the battery management system chip is respectively connected with a second signal end of the first data selector and a first signal end of the second data selector;
the input end of the analog-to-digital converter is connected with the output end of the data selector circuit and used for converting the analog signal input by the data selector circuit into a digital signal and outputting the digital signal;
the output end of the analog-to-digital converter is connected with the input end of a micro-control processor and used for sending the digital signal output by the analog-to-digital converter to the micro-control processor for analysis and processing and monitoring and managing the current;
when the power battery system is in a discharging state, the signal output by the comparator circuit is positive, and the first signal end of the first data selector and the first signal end of the second data selector are gated;
when the power battery system is in a charging state, the signal output by the comparator circuit is negative, and the second signal end of the first data selector and the second signal end of the second data selector are gated.
2. The current sensing system for a power battery system of claim 1, wherein in the comparator circuit:
when the positive phase input signal is greater than the negative phase input signal, the signal output by the comparator circuit is positive;
when the positive phase input signal is less than the negative phase input signal, the signal output by the comparator circuit is negative.
3. The current sensing system for a power battery system of claim 1, wherein the signal output by the comparator circuit is used to control the gating of the data selector circuit.
4. The current sensing system for a power battery system of claim 1, wherein an output of the first data selector is connected to a first input of the analog-to-digital converter;
the output end of the second data selector is connected with the second input end of the analog-to-digital converter.
5. The current sensing system for a power battery system of claim 1, further comprising a current shunt coupled between the first pin of the battery management system chip and the second pin of the battery management system chip.
6. The current sensing system for a power battery system of claim 1, wherein said first data selector and said second data selector include an enable terminal for switching said first data selector and said second data selector on and off.
7. The current sensing system for a power battery system of claim 6, wherein the first data selector and the second data selector are turned on when the signal of the enable terminal is 1;
when the signal of the enable terminal is 0, the first data selector and the second data selector are disconnected.
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| CN201811558011.6A CN109683098B (en) | 2018-12-19 | 2018-12-19 | Current detection system for power battery system |
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| CN201811558011.6A CN109683098B (en) | 2018-12-19 | 2018-12-19 | Current detection system for power battery system |
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| CN102882248A (en) * | 2011-07-15 | 2013-01-16 | 凹凸电子（武汉）有限公司 | Battery management systems with vertical bus circuits |
| CN203587662U (en) * | 2013-10-28 | 2014-05-07 | 无锡中星微电子有限公司 | Current detecting circuit and rechargeable battery |
| CN107843842A (en) * | 2017-09-25 | 2018-03-27 | 中派科技（深圳）有限责任公司 | Battery status monitoring system and method |
| CN108574120A (en) * | 2017-03-10 | 2018-09-25 | 凹凸电子（武汉）有限公司 | Battery system and its management method, battery management module and method |
| CN108594133A (en) * | 2018-05-18 | 2018-09-28 | 向玲丽 | A kind of lithium battery pressure differential detection circuit |
| CN108983867A (en) * | 2017-05-31 | 2018-12-11 | 台湾积体电路制造股份有限公司 | Voltage selecting circuit |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7081737B2 (en) * | 2003-06-19 | 2006-07-25 | O2Micro International Limited | Battery cell monitoring and balancing circuit |
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Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102882248A (en) * | 2011-07-15 | 2013-01-16 | 凹凸电子（武汉）有限公司 | Battery management systems with vertical bus circuits |
| CN203587662U (en) * | 2013-10-28 | 2014-05-07 | 无锡中星微电子有限公司 | Current detecting circuit and rechargeable battery |
| CN108574120A (en) * | 2017-03-10 | 2018-09-25 | 凹凸电子（武汉）有限公司 | Battery system and its management method, battery management module and method |
| CN108983867A (en) * | 2017-05-31 | 2018-12-11 | 台湾积体电路制造股份有限公司 | Voltage selecting circuit |
| CN107843842A (en) * | 2017-09-25 | 2018-03-27 | 中派科技（深圳）有限责任公司 | Battery status monitoring system and method |
| CN108594133A (en) * | 2018-05-18 | 2018-09-28 | 向玲丽 | A kind of lithium battery pressure differential detection circuit |
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