CN105871037B - Battery management system and method - Google Patents

Abstract

The invention discloses a battery management system and method. The system includes: a battery pack, wherein the battery pack is formed by paralleling a plurality of sub-string batteries, and the sub-string batteries are formed by connecting a plurality of single batteries in series; the sub-string battery management system, the number of sub-string battery management systems is the same as the number of sub-strings, and each connection point between the single cells in each group of sub-string batteries leads out two wires, one of which is directly connected to the sub-string batteries The management system is connected, and the other is connected to the battery management system of the sub-string through the thermistor; and the overall battery management system is connected to the battery management system of the sub-string and the control system of the electric vehicle. The invention can find temperature and voltage faults in the shortest time, avoid damage or even fire of the battery pack, and significantly improve the safety performance of the battery pack.

Description

Battery management system and method

technical field

The present invention relates to the technical field of batteries, and in particular, to a battery management system and method.

Background technique

The battery management system (BMS, Battery Management System) is the link between the battery and the vehicle drive system, which can improve the utilization rate of the battery, prevent the battery from overcharging and discharging, prolong the service life of the battery, and monitor the status of the battery.

At present, the composition of the power battery pack of an electric vehicle is relatively complex. Usually, several small single cells are connected in parallel to form a module with a larger capacity, and then many modules are connected in series to form a battery pack with a higher voltage required. Electric motors are powered, and there are even more complex series-parallel schemes. Due to the large number of small single cells in the above modules, the battery management system can only monitor the modules, but cannot specify the voltage and temperature of each single cell. Once a certain battery generates heat due to a fault, it will take a while due to heat conduction. In order to reach the nearest temperature sensor, the BMS often fails to detect the fault in time, which may cause damage to the battery pack or even cause the car to catch fire. If you want to monitor each single battery, the battery management system is too large and complex, and the cost is expensive, which has always been an unsolved problem.

SUMMARY OF THE INVENTION

The present invention provides a battery management system and method to solve the above-mentioned specific problems existing in the prior art.

In order to solve the above technical problems, the present invention provides a battery management system, including:

A battery pack, the battery pack is formed by parallel connection of a plurality of sub-string batteries, the sub-string batteries are formed by a series of single cells, and the total voltage of the sub-string batteries is equal to the total voltage of the battery pack;

Substring battery management system, the number of substring battery management systems is the same as the number of substrings, and each connection point between the single cells in each group of substring batteries leads out two wires, one of which is directly is connected to the sub-string battery management system, and the other is connected to the sub-string battery management system through the thermistor;

as well as

The overall battery management system is connected with the sub-string battery management system and the control system of the electric vehicle through two different CAN buses.

Preferably, a sampling circuit is further connected between the substring battery management system and the single battery.

Preferably, the sub-battery management system and the sampling circuit are integrated into a SoC (System on Chip) chip.

Preferably, a relay is connected in series with each group of sub-string batteries, and the relay is controlled by the overall battery management system.

Preferably, the sub-string battery management system and the overall battery management system are connected through a CAN bus.

Preferably, the general battery management system and other control systems of the electric vehicle are connected through another CAN bus.

Preferably, the thermistor is attached to the unit cell.

The invention also provides a battery management method, using the battery management system, the sub-string battery management system detects the working state of the sub-string batteries, so as to report to the overall battery management system when the sub-string batteries have irreparable faults , the latter disconnects the sub-string battery from other sub-string batteries; the overall battery management system calculates the total current of the battery pack, and cooperates with the sub-string battery management system to control the switch-in, switch-in, and Cut out.

Preferably, when the battery pack is being charged, the overall battery management system disconnects the sub-string batteries that have reached the high voltage alarm level from other sub-string batteries, which ensures that each sub-string battery is fully charged.

Preferably, when the battery pack is discharged, the overall battery management system disconnects the sub-string batteries that reach the low voltage alarm level from other sub-string batteries to ensure that the car can drive to the charging station as normally as possible.

Compared with the prior art, the present invention has the following advantages:

1. The present invention can monitor the temperature and voltage of each single battery, which is not achieved by the previous battery management systems. When a single battery fails, the fault can be found in a shorter time than any previous solution, avoiding damage to the battery pack or even fire, which greatly improves the safety performance of the battery pack;

2. The present invention can use standard and modular SoC chips, and can be mass-produced and applied to reduce cost, volume, and complexity, and solves the problem that in the prior art, the monitoring system faced by each single cell is too large and expensive. The problem;

3. The number of single batteries and the number of sub-string batteries can be adjusted according to actual needs. The assembly of the entire battery management system is as convenient as building blocks and has a wide range of adaptability;

4. The single cells of the present invention are connected in series to reach the required voltage at one time to form sub-string batteries, and then the sub-string batteries are connected in parallel according to the actual needs to achieve the required capacity, and the sub-strings whose string voltage is too low are delayed and merged into the battery pack. In this way, no internal current will be generated inside the battery pack, which is the hidden danger of causing heat and internal consumption. The battery management system proposed by the present invention can make the internal current zero when the vehicle is stopped, because the relays of each substring can be disconnected.

Description of drawings

1 is a schematic structural diagram of a substring battery in a battery management system of the present invention;

FIG. 2 is a connection diagram of the overall battery management system and the substring battery management system in the battery management system of the present invention.

Shown in the picture: 10-substring battery, 101-single battery, 20-substring battery management system, 30-thermistor, 40-total battery management system, 50-sampling circuit

Detailed ways

In order to make the above objects, features and advantages of the present invention more clearly understood, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the accompanying drawings of the present invention are all in a simplified form and use inaccurate scales, and are only used to facilitate and clearly assist the purpose of explaining the embodiments of the present invention.

As shown in FIG. 1 to FIG. 2 , the present invention provides a battery management system, including:

A battery pack, the battery pack is formed by paralleling a plurality of sub-string batteries 10, and the sub-string batteries 10 are formed by connecting a plurality of single cells in series 101;

A sub-string battery management system 20, the number of the sub-string battery management systems 20 is the same as the number of the sub-string batteries 10, and each connection point of the single battery 101 in each group of sub-string batteries 10 leads out two wires, One of them is directly connected to the sub-string battery management system 20 to measure the cell voltage, and the other is connected to the sub-string battery management system 20 through the thermistor 30, and the thermistor 30 is attached to the Specifically, the sub-string battery management system 20 is used to measure the voltage and temperature of each cell in the sub-string battery 10 corresponding to it, and calculate the temperature of the sub-string battery. SOC (battery state of charge), SOH (battery life) and SOP (State Of Power, SOP refers to the next moment such as the next 2 seconds, 10 seconds, 30 seconds when the battery is discharged with a continuous high current when the maximum current can be provided. The discharge power or the charged power), alarm and process the faulty single battery 101, perform active and passive balance on each single battery 101 in the substring battery, and communicate with the overall battery management system 40 at the same time;

as well as

The overall battery management system 40 is connected with the sub-string battery management system 20 and other control systems of the electric vehicle through two different CAN buses. The overall battery management system 40 realizes the switch-in and switch-out of each sub-string battery 10 and the communication with other controllers in the vehicle through communication with the sub-string battery management system 20 . When a certain sub-string battery 10 has an irreparable fault for some reason (temperature, voltage abnormality), the sub-string battery 10 is completely removed from the battery pack, and the power of the whole vehicle is limited at the same time, thereby giving the owner enough time. make repairs.

Preferably, a sampling circuit 50 is further connected between the sub-string battery management system 20 and the single battery string 10. Further, the sub-battery management system 20 and the sampling circuit 50 may be integrated into a SoC (System on Chip) ) chips to reduce size and cost.

Preferably, a relay is connected in series with each group of sub-string batteries 10, and the relay is controlled by the overall battery management system 40. That is to say, in practical applications, it can be determined whether the sub-string batteries 10 need to be connected in series according to the situation. input, which is achieved by using the relay.

Preferably, the sub-string battery management system 20 and the general battery management system 40 are connected through a CAN bus, and the general battery management system 40 and the general control system of the electric vehicle are connected through another CAN bus to achieve Information interaction, and then better management of the entire battery pack.

1 and 2, the present invention also provides a battery management method, using the battery management system, specifically: due to the battery pack of the present invention, the single unit cells 101 are directly connected in series to form a required battery pack. High-voltage sub-string batteries 10, and an independent standardized sub-string battery management system 20 is used on the sub-string batteries 10, so that the voltage, temperature, SOC, and balance of each single battery 101 are monitored. The entire battery pack is composed of several such sub-string batteries 10 in parallel. A general battery management system 40 with relatively simple functions manages the sub-string battery management system 20 , and the sub-string battery management system 20 manages the sub-string batteries 10 . When several or dozens of sub-string batteries 10 are connected in parallel to form a battery pack, the total voltage of each sub-string battery 10 is not necessarily equal (it can be accurately measured when the relay of each sub-string is not turned on), and each sub-string battery 10 The total voltage is calculated by summing the voltages of all cells in series. Therefore, in order to prevent the low-voltage sub-string battery 10 from becoming the load of other sub-string batteries 10 in parallel to form a battery pack, the time when the low-voltage sub-string battery 10 is integrated into the battery pack can be appropriately delayed, that is, when the discharge starts, the voltage The low sub-string battery 10 is not integrated into the overall circuit first, and is then integrated when the voltage of the sub-string battery 10 is equal to the voltage of other sub-string batteries 10 . During the discharge operation, the sub-string batteries 10 whose voltage is too low can also be switched out for a short period of time.

That is to say, the battery management system of the present invention can disconnect the sub-string batteries 10 whose voltage is too low to warn when discharging. Since the capacity of each sub-string battery 10 is not large, the performance of the battery pack without a string has little effect, or at least it can cooperate with the limited power so that the driver can drive the car to the charging station. During charging, the fully charged sub-string batteries 10 can be switched out, so that each sub-string battery 10 can be fully charged. Of course, in this process, the charger needs to cooperate to adjust the charging current. In this way, the equalization cost is much lower than the general active equalization in the past, and at the same time, there is no energy waste inevitably caused by a large equalizing current, and the depth of discharge is also increased. The solution proposed by the present invention to replace the past equilibrium may become the mainstream of the future equilibrium.

Obviously, those skilled in the art can make various changes and modifications to the invention without departing from the spirit and scope of the invention. Thus, provided that these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims (7)

1. a kind of battery management system characterized by comprising

Battery pack, the battery pack are formed in parallel by several substring batteries, the substring battery connected by several single batteries and At the total voltage of substring battery is equal with battery pack total voltage；

The quantity of substring battery management system, the substring battery management system is identical as the quantity of substring, and every group of substring electricity Each tie point in pond between single battery draws two conducting wires, wherein one directly connects with the substring battery management system Connect, another is then connect with the substring battery management system by thermistor, the substring battery management system with it is described Be also connected with sample circuit between single battery, the substring battery management system to the voltage of each section single battery, temperature, SOC, equilibrium are monitored and handle, and communicate with total battery management system；

The sub- battery management system and sample circuit are integrated into SoC (System on Chip) chip, the thermistor patch It is attached on the single battery；

And

Other of total battery management system, total battery management system and the substring battery management system and electric car Controller connection, total battery management system are realized by the communication with substring battery management system to each substring battery It cuts, cut out and the communication with other controllers in automobile.

2. battery management system as described in claim 1, which is characterized in that be in series with a relay on every group of substring battery Device, the relay are controlled by total battery management system.

3. battery management system as described in claim 1, which is characterized in that the substring battery management system and total electricity It is connected between the management system of pond by CAN bus.

4. battery management system as described in claim 1, which is characterized in that total battery management system and electric car It is connected between other control system by another CAN bus.

5. a kind of battery management method, using the battery management system as described in claim 1-4 any one, feature exists The working condition of substring battery is detected in, substring battery management system, so as to when there is the failure of unrepairable in substring battery, Total battery management system disconnects the substring battery and other substring batteries；Total battery management system is in charging and discharging When, according to strategy incision, cut out relevant substring battery.

6. battery management method as claimed in claim 5, which is characterized in that when battery pack charging, total battery management System is up to the substring battery of alarm for high voltage degree and other substring batteries disconnect, to ensure that all substring batteries can be by It is full of.

7. battery management method as claimed in claim 6, which is characterized in that when battery pack electric discharge, total battery management System is up to the substring battery of low pressure alarming degree and other substring batteries disconnect, to ensure that automobile being capable of row as normal as possible Sail to charging station.