CN105896627A - System based on battery pack self-reconfiguration and intelligent control method thereof - Google Patents

Abstract

The invention relates to a system based on battery pack self-reconfiguration and an intelligent control method thereof. The system comprises a battery array, a control portion and an output and input portion. The self-reconfiguration control method is characterized in that during a whole battery pack charging and discharging process, a process of switching into a ''temporary resection battery pack set'' from a ''main circuit battery pack set'', a process of switching into a ''fault battery pack set'' from the ''main circuit battery pack set'', a process of switching into the ''main circuit battery pack set'' from the ''temporary resection battery pack set'' and an ''equalization mode'' process exist; and then, according to a corresponding switching condition, a battery is dynamically switched among the ''main circuit battery pack set'', the ''temporary resection battery pack set'' and the ''fault battery pack set''. The system and the method have advantages that an imbalance problem of the battery pack charging and discharging is solved; an output or input voltage grade can be flexibly configured; flexible battery pack configuration can be used to carry out charging and discharging; and a service life of a battery pack can be prolonged.

Description

A battery pack self-reconfiguration-based system and its intelligent control method

technical field

The invention belongs to the technical field of battery management, and in particular relates to a battery pack self-reconfiguration-based system and an intelligent control method thereof.

Background technique

In mobile devices such as electric vehicles and lunar vehicles, batteries are required as the main source of energy. However, due to the low terminal voltage of the single cells, the single cells need to be connected in series to meet the voltage requirements of the electrical equipment. .

During the charge and discharge process of the battery pack, there is a phenomenon of uneven and unbalanced voltages at the terminals of the single cells. The result of this phenomenon is that the energy utilization rate of the system is greatly reduced. At present, there are two main ways to solve the unbalanced battery pack. One is a passive solution that uses parallel resistors and capacitors for voltage equalization; A good solution to the problems of unbalanced and heating faults; one is an active solution that uses high-voltage single cells in the battery pack to supply power to low-voltage single cells; in this solution, due to the fixed connection method, it is not very good Solve the problem of heating and other failures.

In the current method for solving the charging and discharging of series-connected battery packs, although the problem of fixed connection mode is overcome, in the series-connected battery packs, the problem of imbalance in the process of charging and discharging still exists.

Contents of the invention

The purpose of the present invention is to propose a system based on self-reconfiguration of battery packs and its intelligent control method, which can not only solve the problem of unbalanced battery packs, but also flexibly configure charging and discharging methods and remove faulty battery packs to improve battery life.

The present invention is realized through the following technical solutions:

A system based on self-reconfiguration of a battery pack, characterized in that it includes a battery array, a control part, and an output and input part;

The battery array includes a battery pack and a balancing unit; the battery pack includes a set of single battery cells and a switch Sn (n=1, 2...N: the number of the battery array); the single battery is phosphoric acid Iron-lithium battery; the battery unit includes a single battery and a switch Kn (n=1, 2...N: the number of battery arrays); the single battery is connected in series with the switch Kn; the switch S Connected in parallel with the battery unit; the equalization unit includes a DC module 1, a diode Dn (n=1, 2...2N; N: the number of battery arrays) and a switch Cn (n=1, 2...2N; N: the number of battery arrays); the positive pole of the output terminal of the DC module 1 is connected to the positive pole of the diode D2n+1 (n=0, 1, 2...N-1; N: the number of battery arrays); the said The cathode of the diode D2n+1 (n=0, 1, 2...N-1; N: the number of battery arrays) and the switch C2n+1 (n=0, 1, 2...N-1; N : one end of the battery array) is connected in series; the other end of the switch C2n+1 (n=0, 1, 2...N-1; N: the number of the battery array) is connected to the positive electrode of the battery cell Connection; the negative pole of the output terminal of the DC module 1 is connected to the negative pole of the diode D2n (n=1, 2...N-1; N: the number of battery arrays); the diode D2n (n=1, 2. ..N; N: the number of battery arrays) is connected in series with one end of the switch C2n (n=1, 2...N; N: the number of battery arrays); the switch C2n (n=1, 2 ...N; N: the number of the battery array) the other end is connected to the negative pole of the battery unit; the switch Kn, the switch Sn, and the switch Cn are MOSFETs; The IO pins are connected; the switch Kn and the switch Sn are mutually exclusive; the switch C2n and the switch C2n+1 are linked.

The control part includes a controller and a touch screen; the temperature sensor is placed on the surface of each single battery in the battery array; the controller detects the surface temperature of each single battery in the battery array through the temperature sensor The voltage sensor is connected in parallel with the battery cells in the battery array; the controller detects the terminal voltage of each single battery in the battery array through the voltage sensor; the current sensor is connected to the positive pole of the output terminal of the battery array connected in series; the controller detects the current of the battery array through a current sensor; the touch screen is connected to the controller; the controller also detects the output terminal voltage of the output and input part through a voltage sensor.

The output and input part includes a DC-DC module 2 with a wide voltage range and a reversing switch; the positive pole of the input terminal of the output and input part is Vin (+), the negative pole is Vin (-), and the positive pole of the output terminal is Vout (+ ), the negative pole is Vout (-); the positive pole of the input end of the DC-DC module 2 of the wide voltage range is Vi (+), and the negative pole is Vi (-); the DC-DC module 2 of the wide voltage range The positive pole of the output terminal is Vo (+), and the negative pole is Vo (-); the Vin (+) of the output and input part is connected with the positive pole of the battery array through the current sensor; the output and input part of the Vin(-) is connected to the negative pole of the battery array; the reversing switch includes JM_i, JM_i' (i=1, 2, 3, 4); one end of the switch JM_4 is connected to Vin(+) , the other end is connected to Vi (+); one end of the switch JM_2 is connected to Vout (+), and the other end is connected to Vi (+); one end of the switch JM_3 is connected to Vin (+), and the other end is connected to Vo(+) is connected; one end of the switch JM_1 is connected to Vout(+), and the other end is connected to Vo(+); one end of the switch JM_4' is connected to Vin(-), and the other end is connected to Vi(-) connection; one end of the switch JM_3' is connected to Vout(-), and the other end is connected to Vi(-); one end of the switch JM_2' is connected to Vin(-), and the other end is connected to Vo(-); One end of the switch JM_1' is connected to Vout(-), and the other end is connected to Vo(-); the switches JM_i, JM_i' (i=1, 2, 3, 4) are MOSFETs; the switch JM_i , JM_i' is the linkage switch.

An intelligent control method based on battery pack self-reconfiguration, characterized in that:

The entire battery pack is divided into "main road battery pack collection", "temporarily cut off battery pack collection", and "faulty battery pack collection"; among them, "main road battery pack collection"----the normal working battery pack in the battery array ;"Temporarily cut off the battery set"----the battery set temporarily cut off from the battery array, and then cut it into the "main road battery set" when appropriate; "Faulty battery set"----permanently cut off from the battery array The battery pack needs to be replaced in time by maintenance personnel. In the charging and discharging process of the battery pack, there are four sub-processes, taking the discharging process as an example:

1) The process of switching from the "main road battery pack set" to "temporarily cut off the battery pack set": set a voltage drop rate threshold V _threshold value in advance according to the discharge characteristics of the single battery; Then calculate the voltage drop rate of each single battery according to the following formula: When V _{n_down} > V _threshold value, cut off this single cell from the "main road battery set" to the "temporarily cut off battery set".

2) The process of switching from the "main battery set" to the "faulty battery set": when the total voltage in the "main battery set" is less than the minimum voltage requirement of the DC module, the "temporarily cut off the battery set" All the batteries in the battery are cut into the "main road battery pack collection".

3) The process of switching from "temporarily cut off battery set" to "main road battery set": when the total voltage in the "main road battery set" is less than the minimum voltage requirement of the DC module, "temporarily cut off the battery set" "All the batteries in" are cut into the "main road battery pack collection".

4) "Balance mode" process: one way is to use the battery with high terminal voltage in the "main battery pack set" to supply power to the battery with low terminal voltage. The terminal voltage of each battery is numbered according to the order of the terminal voltage from low to high, so that the highest number supplies power to the lowest number, the second highest number supplies power to the second lowest number, and so on; another way is to use external (can be " The main road battery set" supplies power to the battery with low terminal voltage through the output voltage of the DC module. During this process, the terminal voltage of each battery in the "main road battery set" is dynamically monitored, and then the average value is calculated. Below average battery for power.

An intelligent control method based on self-reconfiguration of battery packs. According to the above-mentioned various conditions, the battery is dynamically placed between the "main road battery pack set", "temporarily cut off battery pack set", and "faulty battery pack set". Switch, the steps of its self-reconfiguration method are as follows:

Step 1: First judge whether the condition of cutting off from the "main road battery set" to "temporarily cut off battery set" is satisfied, and if so, cut off the single battery from the "main road battery set" to the "temporarily cut off battery set" Collection".

Step 2: Determine whether the condition of cutting off from the "main battery set" to the "faulty battery set" is met, and if so, cut off the single battery from the "main battery set" to the "faulty battery set" .

Step 3: Determine whether the condition of switching from the "temporarily cut off battery set" to the "main road battery set" is met, and if so, cut all the batteries in the "temporarily cut off battery set" into the "main road battery set" .

Step 4: Determine whether the conditions of the "balance mode" are met, and if the conditions are met, the batteries in the "main road battery set" enter the process of "balance mode".

Step 5: During the whole discharge process, the above process repeats steps 1, 2, 3, 4, 5 continuously until the discharge ends.

The advantages of the present invention are:

1) Solve the imbalance problem of charging and discharging of the battery pack;

2) The level of output or input voltage can be flexibly configured;

3) Capable of charging and discharging with flexible battery pack configuration;

4) It can improve the service life of the battery pack;

Description of drawings

FIG. 1 is a system block diagram of an embodiment of the present invention.

Fig. 2 is a flow chart of the discharge process of the embodiment of the present invention.

Fig. 3 is a flow chart of the "balance mode" process in the embodiment of the present invention.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and examples, and the protection scope of the present invention is not limited to the following description.

Example:

Fig. 1 is the system block diagram of the embodiment of the present invention; It comprises " battery array ", " control section ", " input/output section "; The function that it realizes is:

1) Monitor the voltage, temperature and current of the battery pack in real time;

2) Certain batteries can be removed/added dynamically;

3) Through the "DC module 1" can dynamically charge a certain battery;

4) Ensure that the entire system can be charged and discharged;

Below, for the above functions, the statement is as follows:

Each terminal in the battery array is connected to a voltage and temperature sensor, and a current sensor (Hall sensor) is connected to the output of the battery array. The controller of the "control part" collects the values of these sensors to monitor the voltage of the battery pack in real time. , temperature, current. In Figure 1 "Control Part", the solid line "-" represents the connection line of the voltage sensor; the dotted arrow "---→" represents the connection line of the temperature sensor; the dotted ellipse Represents the wiring of the current sensor (Hall sensor).

When the battery pack is working normally, K1---KN is closed, and the corresponding switches S1---SN, C1---C2N are disconnected; when a fault occurs or the battery is dynamically removed, for example, if you want to remove the battery 2. You only need to send control signals to the switches K2 and S2 through the controller, open the switch K2 and close the switch S2, and the others are similar; when you want to cut a certain battery into the battery pack, for example, put the battery 3 To cut into the battery pack, you only need to send control signals to the switches K3 and S3 through the controller, close the switch K3, and open the switch S3. .

If the "DC module 1" supplies power to the corresponding battery n, the switches C2n-1 and C2n will be closed at the same time; if the power supply is stopped, the switches C2n-1 and C2n will be turned off at the same time; Dynamically charge a certain battery. In order to prevent a short circuit between lines and ensure the normal operation of the power supply path, a forward-connected diode is added to the path of the switch Cx (x represents the number of the switch, from 1 to 2N).

In order to ensure that the whole system can both charge and discharge, the overall connection diagram of its "wide input voltage DC module 2" is shown in the "input/output part"; when the system enters the charging mode, switches JM_2, JM_2', JM_3, JM_3 'closed, the switches JM_1, JM_1', JM_4, JM_4' are opened; when the system enters the discharge mode, the switches JM_1, JM_1', JM_4, JM_4' are closed, and the switches JM_2, JM_2', JM_3, JM_3' are opened.

The "No. 1 switch" in Figure 1 represents the specific hardware implementation of the switches Sn and Kn (n=1, 2...N: the number of battery arrays) inside the battery array. The switch Kn is an N-type switch tube, and Sn is a P-type switch. The working principle of the switch tube is: when writing 1 to the "drive board control pin", the switch Kn is turned on and the switch Sn is turned off; when 0 is written, the switch Sn is turned on and the switch Kn is turned off; "No. 2 switch" Represents the specific hardware implementation of the C2n and C2n-1 switches inside the battery array. C2n-1 and C2n are N-type switch tubes. Their working principle is: when writing 1 to the "drive board control pin", the switches C2n, C2n+1; when writing 0, then turn on switch C2n, C2n+1; "No. 3 switch" represents the specific hardware implementation of JM_i, JM_i' (i=1, 2, 3, 4) switches, and it is the same as "No. 2 switch" "Similar.

Based on the above hardware design, a self-reconfiguration control method is implemented on the controller; in order to facilitate the description of the discharge process, the entire discharge process is split into two parts, Figure 2 and Figure 3; where Figure 2 is the embodiment of the present invention Discharging process flow chart; FIG. 3 is a process flow chart of the "equilibrium mode" in the embodiment of the present invention. Figure 2 and Figure 3 are described below:

1) The discharge process flow chart of the entire system is shown in Figure 2, where the meanings of each mark are as follows:

① "Vdown" represents the voltage drop rate of the battery terminal voltage in the "main road battery set", and its value is calculated according to formula (1).

② "V threshold" represents the terminal voltage drop rate threshold value set according to the discharge characteristics of the single battery.

③ "BT" represents the temperature of the battery in the "main road battery set".

④ "B Threshold" represents the upper temperature limit set in the "Main Road Battery Set".

⑤ "Vleft" represents the total voltage of the battery in the "main road battery set".

⑥ "Vdc_min" represents the lower limit value of the input voltage range of the DC module in the "input/output part" in Figure 1.

⑦ "N Temporarily Removed Battery Sets" represents the number of batteries in the "Temporarily Removed Battery Sets".

The working process is as follows: first close the switches JM_1, JM_1', JM_4, JM_4', disconnect the switches JM_2, JM_2', JM_3, JM_3', and enter the discharge mode; when the discharge mode starts, put all the batteries in the battery pack into In "Main Road Battery Pack Collection", then proceed as follows:

a) Dynamically scan every certain time interval whether the voltage drop rate of each battery in the "main battery set" is greater than the preset drop rate threshold, if it is true, transfer this battery from the "main battery" group set" to the "temporarily removed battery set set"; after all the batteries in the "main road battery set set" have been scanned, go to step b).

b) Dynamically scan every certain time interval whether the temperature of each battery in the "main road battery set" is greater than the preset temperature upper limit value, if it is true, put this battery into the "main road battery set" ” into the “Faulty Battery Set”; after all the batteries in the “Main Road Battery Set” are scanned, go to step c).

c) Determine whether the total voltage of the batteries in the "main battery set" is less than the lower limit of the input voltage of the DC module. group" set; then enter step d).

d) Determine whether the total voltage of the batteries in the "main road battery set" is less than the lower limit of the input voltage of the DC module, and at the same time whether the number of batteries in the "temporarily cut off the battery set" is zero, if true, enter the " Balance mode" process; otherwise repeat steps a), b), c), d).

2) The process flow chart of "balanced mode" is shown in Figure 3, where the meanings of each mark are as follows:

① "Vmean" represents the average voltage of the battery in the "main road battery set".

② "N1" represents the number of batteries in the "main road battery set".

③ "i" = represents a variable, used to store the number of cycles.

④ "VB_i" represents the terminal voltage of the i-th cell of the discharged battery pack.

⑤ "V over-discharge" represents the over-discharge voltage set for each battery during the discharge process.

The working process is: when the discharge starts, first set the variable i to 1; then follow the steps below:

a) Determine whether the terminal voltage VB_i of the i-th battery is less than the set battery over-discharge protection voltage V over-discharge, if it is less than, directly remove this battery from the "main battery set"; then enter step b).

b) Determine whether the total voltage Vleft in the "main road battery set" is less than the lower limit value Vdc_min of the input voltage of the DC module, if less, directly end the discharge process; otherwise, enter step c).

c) According to the formula Calculate the average voltage Vmean in the "main road battery set"; then judge whether the battery terminal voltage VB_i in the "main road battery set" is less than Vmean, if it is true, then close the switches C2i, C2i+1, and make the variable i Increment by 1; if false, open switches C2i, C2i+1 and increment variable i by 1.

d) Determine whether i is equal to N1, and if it is true, set the variable i to 1; then enter step e).

e) Repeat steps a), b), c), and d).

Claims (8)

1. A system based on self-reconfiguration of battery packs, characterized in that: comprising a battery array, a control part and an output and input part; The battery array includes a battery pack and a balancing unit; the battery pack includes a set of single battery cells and a switch Sn (n=1, 2...N: the number of the battery array); The battery unit includes a single battery and a switch Kn (n=1, 2...N: the number of the battery array); The single battery is connected in series with the switch Kn; The switch S is connected in parallel with the battery unit; The equalization unit includes a DC module 1, a diode Dn (n=1, 2...2N; N: the number of battery arrays) and a switch Cn (n=1, 2...2N; N: the number of battery arrays ); The anode of the output terminal of the DC module 1 is connected to the anode of the diode D2n+1 (n=0, 1, 2...N-1; N: the number of battery arrays); The cathode of the diode D2n+1 (n=0, 1, 2...N-1; N: the number of battery arrays) and the switch C2n+1 (n=0, 1, 2...N-1 ; N: the number of battery arrays) connected in series at one end; The other end of the switch C2n+1 (n=0, 1, 2...N-1; N: the number of battery arrays) is connected to the positive pole of the battery unit; The negative pole of the output terminal of the DC module 1 is connected to the negative pole of the diode D2n (n=1, 2...N-1; N: the number of battery arrays); The anode of the diode D2n (n=1, 2...N; N: the number of battery arrays) is connected in series with one end of the switch C2n (n=1, 2...N; N: the number of battery arrays) ; The other end of the switch C2n (n=1, 2...N; N: the number of the battery array) is connected to the negative pole of the battery unit; the switch Kn, the switch Sn, and the switch Cn are MOSFETs; The switch Kn and the switch Sn are mutually exclusive; the switch C2n and the switch C2n+1 are linked. 2. The control part comprising a controller and a touch screen as claimed in claim 1 based on a battery pack self-reconfiguration system; The temperature sensor is placed on the surface of each single battery in the battery array; The controller detects the surface temperature of each single battery in the battery array through a temperature sensor; The voltage sensor is connected in parallel with the battery cells in the battery array; The controller detects the terminal voltage of each single battery in the battery array through a voltage sensor; The current sensor is connected in series with the positive pole of the output end of the battery array; The controller detects the current of the battery array through a current sensor; The touch screen is connected to the controller; The controller also detects the output terminal voltage of the output-input part through a voltage sensor. 3. As claimed in claim 1, the output and input part of a system based on self-reconfiguration of the battery pack comprises a DC-DC module 2 and a reversing switch of a wide voltage range; The positive pole of the input terminal of the output and input part is Vin (+), the negative pole is Vin (-), the positive pole of the output terminal is Vout (+), and the negative pole is Vout (-); The positive pole of the input end of the DC-DC module 2 of the wide voltage range is Vi(+), and the negative pole is Vi(-); The positive pole of the output end of the DC-DC module 2 in the wide voltage range is Vo(+), and the negative pole is Vo(-); The Vin(+) of the output and input part is connected to the positive pole of the battery array through the current sensor; The Vin(-) of the output and input part is connected to the negative pole of the battery array; Described reversing switch comprises JM_i, JM_i' (i=1,2,3,4); One end of the switch JM_4 is connected to Vin(+), and the other end is connected to Vi(+); One end of the switch JM_2 is connected to Vout(+), and the other end is connected to Vi(+); One end of the switch JM_3 is connected to Vin(+), and the other end is connected to Vo(+); One end of the switch JM_1 is connected to Vout(+), and the other end is connected to Vo(+); One end of the switch JM_4' is connected to Vin(-), and the other end is connected to Vi(-); One end of the switch JM_3' is connected to Vout(-), and the other end is connected to Vi(-); One end of the switch JM_2' is connected to Vin(-), and the other end is connected to Vo(-); One end of the switch JM_1' is connected to Vout(-), and the other end is connected to Vo(-); The switches JM_i, JM_i' (i=1, 2, 3, 4) are MOSFETs; the switches JM_i, JM_i' are linkage switches. 4. An intelligent control method based on battery pack self-reconfiguration, characterized in that: The battery packs are divided into "main road battery pack collection", "temporarily cut off battery pack collection", and "faulty battery pack collection"; among them, "main road battery pack collection"----battery packs working normally in the battery array; "Temporarily cut off the battery set" - the battery set temporarily cut off from the battery array, and then cut it into the "main road battery set" when appropriate; "Faulty battery set" ---- permanently cut off from the battery array The battery pack needs to be replaced by maintenance personnel in time. In the charging and discharging process of the battery pack, there are four sub-processes: the process of switching from the "main battery pack set" to the "temporarily cutting off the battery pack set", and switching from the "main road battery pack set" to the "faulty battery pack set" The process of switching from "temporarily cutting off the battery pack collection" to the "main road battery pack collection" process, and the "balanced mode" process; The steps are as follows: Step 1: First judge whether the condition of cutting off from the "main road battery set" to "temporarily cut off battery set" is satisfied, and if so, cut off the single battery from the "main road battery set" to the "temporarily cut off battery set" collection"; Step 2: Determine whether the condition of cutting off from the "main battery set" to the "faulty battery set" is met, and if so, cut off the single battery from the "main battery set" to the "faulty battery set" ; Step 3: Determine whether the condition of switching from the "temporarily cut off battery set" to the "main road battery set" is met, and if so, cut all the batteries in the "temporarily cut off battery set" into the "main road battery set" ; Step 4: Determine whether the condition of "Balance Mode" is met, and if the condition is met, the batteries in the "Main Road Battery Set" enter the process of "Balance Mode"; Step 5: During the whole discharge process, the above process repeats steps 1, 2, 3, 4, 5 continuously until the discharge ends. 5. As described in claim 4, an intelligent control method based on self-reconfiguration of battery packs, the conditions for the process of switching from "main road battery pack collection" to "temporarily removing battery pack collection", taking discharge as an example: According to the discharge characteristics of the bulk battery, set a voltage drop rate threshold V _threshold ; detect the terminal voltage of the single cell according to a certain time interval T, and then calculate the voltage drop rate of each single cell according to the following formula: When V _{n_down} > V _threshold value, cut off this single cell from the "main road battery set" to the "temporarily cut off battery set". 6. As described in claim 4, an intelligent control method based on self-reconfiguration of battery packs, the conditions for the process of switching from the "main road battery pack set" to the "faulty battery pack set", taking discharge as an example: when the "main road battery pack set" When the total voltage in the "battery set" is lower than the minimum voltage requirement of the DC module, all the batteries in the "temporarily cut off battery set" are cut into the "main battery set". 7. As described in claim 4, an intelligent control method based on self-reconfiguration of battery packs, the conditions for the process of switching from "temporarily cutting off the battery pack set" to the "main road battery set set", taking discharge as an example: when the "main road battery pack set" When the total voltage in the "battery set set" is less than the minimum voltage requirement of the DC module, all the batteries in the "battery set set temporarily cut off" will be cut into the "battery set set of the main road". 8. As described in claim 4, an intelligent control method based on self-reconfiguration of battery packs, the process of "equilibrium mode", taking discharge as an example: one way is to use a battery with a high terminal voltage in the "main road battery pack set" to supply During this process, the terminal voltage of each battery in the "main road battery set" is dynamically monitored, and then numbered according to the order of terminal voltage from low to high, so that the highest number supplies power to the lowest number, and the second highest number supplies power to the lowest number. The other way is to supply power to the battery with low terminal voltage from the outside (it can be the output voltage of the "main road battery pack" through the DC module), and in this process, the dynamic Monitor the terminal voltage of each battery in the "main road battery pack set", then calculate its average value, and supply power to the batteries that are lower than the average value.