A battery cell fracture online support device and method

Abstract

The present invention provides an online support device for battery single cell fracture, comprising a battery group consisting of more than one battery connected in series, a general control unit, a group control unit, a battery fracture support unit and a battery fracture identification unit corresponding to each battery; wherein the battery fracture identification unit is connected in parallel to both ends of each battery, the battery fracture support unit is connected across two adjacent batteries, the group control unit is connected to the battery fracture support unit, the battery fracture identification unit is connected to the general control unit, and the general control unit is connected to the group control unit.

Description

Technical Field

[0001] The invention relates to the field of battery protection, in particular to an online supporting device and method for a broken battery cell. Background Art

[0002] Most DC power supply systems use batteries in series as important emergency backup power sources. When the main power source is cut off, the battery group will change from a backup power source to a main power source to supply power to the load. At this time, if a single battery breaks, it will cause the entire battery group to lose power if monitoring and protection are not in place. The entire DC power supply system loses power instantly, causing irreparable huge losses to the operation of the power grid. At present, the main technical means for handling battery cell break failures are concentrated on establishing a current bypass unit to bypass the faulty single cell. The current bypass unit can be a power diode or a relay control unit. By bridging the faulty battery, the impact of a single battery failure on the entire DC system can be solved. However, the above method can only bridge and shunt the current of the battery group, and cannot support the voltage of the entire group. Especially when multiple single cells break at the same time, the voltage of the entire group drops greatly. If the power-off voltage value is reached, the entire battery group will be out of use, and the power of the remaining unbroken battery cells cannot be fully utilized due to insufficient discharge. Summary of the invention

[0003] Purpose of the invention: The technical problem to be solved by the present invention is to provide an online support device and method for a battery cell fracture in view of the deficiencies in the prior art.

[0004] In order to solve the above technical problems, the present invention provides an online support device for battery cell fracture, comprising a battery group consisting of more than one battery connected in series, a general control unit, a group control unit, a battery fracture support unit and a battery fracture identification unit corresponding to each battery; wherein the battery fracture identification unit is connected in parallel to both ends of each battery, the battery fracture support unit is bridged between two adjacent batteries, the group control unit is connected to the battery fracture support unit, the battery fracture identification unit is connected to the general control unit, and the general control unit is connected to the group control unit.

[0005] The battery fracture support unit includes a first switch tube, a second switch tube, an energy storage inductor, a first capacitor connected between the first switch tube and the energy storage inductor, and a second capacitor connected between the second switch tube and the energy storage inductor. One end of the energy storage inductor is connected between two adjacent batteries, and the other end is connected between the first switch tube and the second switch tube. One end of the first switch tube is connected to the positive electrode of the battery, and the other end is connected to the second switch tube. One end of the second switch tube is connected to the first switch tube, and the other end is connected to the negative electrode of the adjacent battery. The control end of the first switch tube and the control end of the second switch tube are respectively connected to the grouping control unit.

[0006] The two adjacent batteries include a battery B1 and a battery B2. The two adjacent batteries include a battery B1 and a battery B2; the battery rupture identification unit corresponding to the battery B1 is a first battery rupture identification unit, and the battery rupture identification unit corresponding to the battery B2 is a second battery rupture identification unit.

[0007] In the present invention, the first port of the battery rupture support unit is connected to the positive electrode of the battery B1, the second port of the battery rupture support unit is connected to the negative electrode of the battery B1, and the third port 3c of the battery rupture support unit is connected to the negative electrode of the battery B2.

[0008] In the present invention, the first port of the first battery rupture identification unit is connected to the positive electrode of the battery B1, the third port of the first battery rupture identification unit is connected to the negative electrode of the battery B1, the first port of the second battery rupture identification unit is connected to the positive electrode of the battery B2, the third port of the second battery rupture identification unit is connected to the negative electrode of the battery B2, and the second port of the first battery rupture identification unit and the second port of the second battery rupture identification unit are respectively connected to the overall control unit.

[0009] The present invention also provides an online support method for battery cell fracture, in which a battery fracture identification unit continuously samples the terminal voltages of all battery cells in real time in a floating charge state or a battery pack charge and discharge state;

[0010] When any battery in the battery pack breaks, the internal resistance R b Increase, the battery pack current will be in the battery internal resistance R b A voltage drop is generated on the b The voltage drop gradually increases, resulting in a reverse voltage at both ends of the faulty battery. The battery rupture identification unit detects that the battery terminal voltage is a negative value, determines that the battery is in a rupture state, and sends a signal to the main control unit. The main control unit sends a signal to start the group control unit.

[0011] The group control unit sends a signal to control the first switch tube and the second switch tube in the battery fracture support unit connected between the faulty battery and the adjacent battery, so that the adjacent battery is discharged through the energy storage inductor, and the discharge current forms a loop through the energy storage inductor, the second switch tube, and the negative electrode of the adjacent battery. At the same time, the discharge current flows through the first switch tube to charge the first capacitor connected between the first switch tube and the energy storage inductor, thereby supporting the voltage of the broken battery and further supporting the voltage of the battery pack;

[0012] The loop formed by the energy storage inductor and the first switch tube in the broken support unit provides a current channel for the battery pack current, so that the battery pack current can avoid the broken battery and flow through the broken support unit.

[0013] Beneficial effects:

[0014] 1. When a single cell in the battery pack breaks, the broken cell can be detected in time and the battery pack current can be bypassed to avoid the entire battery pack being unavailable due to a single cell failure;

[0015] 2. It can more effectively support the voltage of the entire battery group, and will not cause the voltage of the entire group to drop too much due to the breakage of some battery cells, thus affecting the normal operation of the DC system;

[0016] 3. The fracture support unit has a simple structure and can complete the detection of faulty batteries and the voltage and current support of the entire battery group at a relatively low component cost, thus more effectively ensuring the safe and stable operation of the DC system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. The above and other advantages of the present invention will become more clear.

[0018] Figure 1 It is a schematic diagram of the online supporting device for a battery cell fracture of the present invention.

[0019] Figure 2 It is a schematic diagram of the battery fracture support unit of the present invention. DETAILED DESCRIPTION

[0020] The present invention will be described in detail below with reference to the accompanying drawings.

[0021] like Figure 1As shown, the online support device for battery cell fracture comprises a battery group consisting of more than one battery connected in series, a general control unit 1, a group control unit 2, a battery fracture support unit 3 and a battery fracture identification unit corresponding to each battery, wherein the battery fracture identification unit is connected in parallel to both ends of the battery, the battery fracture support unit 3 is connected across two adjacent batteries, the group control unit 2 is connected to the battery fracture support unit 3, the battery fracture identification unit is connected to the general control unit 1, and the general control unit 1 is connected to the group control unit 2.

[0022] The battery fracture support unit 3 is connected across two adjacent batteries, which means that: a battery fracture support unit 3 is provided between every two adjacent batteries, the two adjacent batteries include a battery B1 and a battery B2, the first port 3a of the battery fracture support unit 3 is connected to the positive electrode of the battery B1, the second port 3b of the battery fracture support unit 3 is connected to the negative electrode of the battery B1, and the third port 3c of the battery fracture support unit 3 is connected to the negative electrode of the battery B2.

[0023] The battery break recognition unit corresponding to the battery B1 is a first battery break recognition unit 4 , and the battery break recognition unit corresponding to the battery B2 is a second battery break recognition unit 5 .

[0024] The first port 4a of the first battery rupture identification unit 4 is connected to the positive electrode of the battery B1, the third port 4c of the first battery rupture identification unit 4 is connected to the negative electrode of the battery B1, the first port 5a of the second battery rupture identification unit 5 is connected to the positive electrode of the battery B2, the third port 5c of the second battery rupture identification unit 5 is connected to the negative electrode of the battery B2, and the second port 4b of the first battery rupture identification unit 4 and the second port 5b of the second battery rupture identification unit 5 are both connected to the overall control unit 1.

[0025] like Figure 2 As shown, the battery break support unit 3 includes a first switch tube 6, a second switch tube 7, an energy storage inductor 8, a first capacitor 9 connected between the first switch tube 6 and the energy storage inductor 8, and a second capacitor 10 connected between the second switch tube 7 and the energy storage inductor 8. One end of the energy storage inductor 8 is connected between two adjacent batteries, and the other end is connected between the first switch tube 6 and the second switch tube 7. One end of the first switch tube 6 is connected to the positive electrode of the battery, and the other end is connected to the second switch tube 7. One end of the second switch tube 7 is connected to the first switch tube 6, and the other end is connected to the negative electrode of the adjacent battery. The control end of the first switch tube 6 and the control end of the second switch tube 7 are respectively connected to the group control unit 2, and the diodes connected in parallel with the first switch tube 6 and the second switch tube 7 are parasitic diodes, which play a role in protecting the switch tubes. The first switch tube and the second switch tube use power MOSFETs, and the voltage drop generated when they are fully turned on is as small as possible.

[0026] The battery fracture identification unit is a sampling and conditioning circuit composed of an operational amplifier LM258, resistors, capacitors, etc. It identifies the fractured battery cell by sampling the battery cell terminal voltage, and simultaneously samples the energy storage inductor current of the battery support unit and provides it to the overall control unit.

[0027] The main control chip of the general control unit adopts TI's TMS320F28335. The general control unit obtains the battery cell information and the energy storage inductor current information of the battery support unit through the sampling of the battery rupture identification unit, and sends a PWM signal with appropriate frequency and duty cycle to the corresponding group control unit.

[0028] The group control unit is a drive circuit composed of a power management chip UC2845, a drive transformer, etc., which sends a drive signal to control the on and off of the switch tube in the battery support unit.

[0029] The present invention also provides an online support method for a battery cell fracture. Taking the fracture of the battery cell B1 as an example, the steps of implementing the method are specifically described:

[0030] Step 1: In the floating charge state or the battery pack charge and discharge state, the battery rupture identification unit continuously samples the terminal voltages of all battery cells in real time;

[0031] Step 2: When the battery cell B1 in the battery pack breaks, the internal resistance R b Increase, the battery pack current will be in the battery internal resistance R b A voltage drop is generated on the b The voltage drop gradually increases, resulting in a reverse voltage at both ends of the faulty battery. The battery rupture identification unit detects that the battery terminal voltage is a negative value, determines that the battery is in a rupture state, and sends a signal to the main control unit 1. The main control unit 1 sends a signal to start the group control unit 2.

[0032] Step 3: The group control unit 2 sends a signal to control the first switch tube 6 and the second switch tube 7 in the battery fracture support unit 3 connected between the faulty battery B1 and the adjacent battery B2, and the adjacent battery B2 is discharged through the energy storage inductor 8. The discharge current forms a loop through the energy storage inductor 8, the second switch tube 7, and the negative electrode of the adjacent battery B2. At the same time, the discharge current flows through the first switch tube 6 to charge the first capacitor 9 connected between the first switch tube 6 and the energy storage inductor 8, so as to support the voltage of the fractured battery and further support the voltage of the battery pack.

[0033] Step 4: The loop formed by the energy storage inductor 8 and the first switch tube 6 in the broken support unit provides a current channel for the battery pack current, so that the battery pack current can avoid the broken battery and flow through the broken support unit.

[0034] The experiment can simulate the situation where a single cell breaks during the discharge process of the battery. For example, the experimental environment is a battery pack composed of 24 2V single cells connected in series, with a load current of 25A. The group voltage before the break is measured to be 49.69V, and the group current is measured to be 25.29A. It is simulated that 4 of the cells break in sequence. After the first cell breaks, the group voltage is 49.59V. Due to the voltage support function of the break support unit and the extremely low voltage drop of the switch tube, the group voltage only drops by 0.1V compared with before the break. After the fourth cell breaks, the group voltage is 48.18V, and the group current is measured to be 24.6A. It can be seen that even if 4 cells break at the same time, the group voltage does not change much after the break. This method achieves effective support for the battery group voltage without affecting the normal operation of the load.

[0035] The present invention provides an online support device and method for a battery cell fracture. There are many methods and ways to implement the technical solution. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be considered as the protection scope of the present invention. All components not specified in this embodiment can be implemented by existing technologies.

Claims

1. An online support device for a battery cell fracture, It is characterized in that The invention comprises a battery pack consisting of more than one battery connected in series, a general control unit (1), a group control unit (2), a battery fracture support unit (3), and a battery fracture identification unit corresponding to each battery; wherein the battery fracture identification unit is connected in parallel to both ends of each battery; the battery fracture support unit (3) is connected across two adjacent batteries; the group control unit (2) is connected to the battery fracture support unit (3), the battery fracture identification unit is connected to the general control unit (1), and the general control unit (1) is connected to the group control unit (2); The battery rupture identification unit is used to identify the broken battery cell by sampling the corresponding battery cell terminal voltage, and at the same time sample the energy storage inductor current of the corresponding battery support unit, and provide it to the general control unit; The general control unit is used to send a PWM signal with an appropriate frequency and duty cycle to the corresponding group control unit based on the battery cell information and the energy storage inductor current information of the battery support unit sampled by the battery rupture identification unit; The group control unit is used to send a drive signal to control the on and off of the switch tube in the battery support unit, so that the battery fracture support unit (3) corresponding to the fractured battery cell supports the corresponding fractured battery voltage and allows the battery pack current to flow; The battery fracture support unit (3) comprises a first switch tube (6), a second switch tube (7), an energy storage inductor (8), a first capacitor (9) bridged between the first switch tube (6) and the energy storage inductor (8), and a second capacitor (10) bridged between the second switch tube (7) and the energy storage inductor (8); one end of the energy storage inductor (8) is connected between two adjacent batteries, and the other end is connected between the first switch tube (6) and the second switch tube (7); one end of the first switch tube (6) is connected to the positive electrode of the battery, and the other end is connected to the second switch tube (7); one end of the second switch tube (7) is connected to the first switch tube (6), and the other end is connected to the negative electrode of the adjacent battery; the control end of the first switch tube (6) and the control end of the second switch tube (7) are respectively connected to the group control unit (2); The two adjacent batteries include battery B 1 and battery B 2 ; With the battery B 1 The corresponding battery rupture identification unit is a first battery rupture identification unit (4), which is connected to the battery B 2 The corresponding battery rupture identification unit is a second battery rupture identification unit (5); The first port (3a) of the battery fracture support unit (3) is connected to the battery B 1 The positive electrode of the battery B is connected to the second port (3b) of the battery fracture support unit (3). 1 The negative electrode of the battery B is connected to the third port (3c) of the battery fracture support unit (3). 2 The negative electrode; The first port (4a) of the first battery rupture identification unit (4) is connected to the battery B 1 The third terminal (4c) of the first battery rupture identification unit (4) is connected to the positive electrode of the battery B. 1 The first terminal (5a) of the second battery rupture identification unit (5) is connected to the negative electrode of the battery B. 2 The third terminal (5c) of the second battery rupture identification unit (5) is connected to the positive electrode of the battery B. 2 The negative electrode of the first battery rupture identification unit (4) and the second port (5b) of the second battery rupture identification unit (5) are respectively connected to the main control unit (1); In the floating charge state or the battery pack charge and discharge state, the battery rupture identification unit continuously samples the terminal voltage of all battery cells in real time; When any battery in the battery pack breaks, the internal resistance R b Increase, the battery pack current will be in the battery internal resistance R b A voltage drop is generated on the b The voltage drop gradually increases, resulting in a reverse voltage at both ends of the faulty battery. The battery rupture identification unit detects that the battery terminal voltage is a negative value, determines that the battery is in a rupture state, and sends a signal to the main control unit (1). The main control unit (1) sends a signal to start the group control unit (2); The group control unit (2) sends a signal to control the first switch tube (6) and the second switch tube (7) in the battery fracture support unit (3) connected between the faulty battery and the adjacent battery, so that the adjacent battery discharges through the energy storage inductor (8), and the discharge current forms a loop through the energy storage inductor (8), the second switch tube (7), and the negative electrode of the adjacent battery. At the same time, the discharge current flows through the first switch tube (6) to charge the first capacitor (9) connected between the first switch tube (6) and the energy storage inductor (8), thereby supporting the voltage of the broken battery and further supporting the voltage of the battery group; The loop formed by the energy storage inductor (8) and the first switch tube (6) in the broken support unit provides a current path for the battery pack current, so that the battery pack current can avoid the broken battery and flow through the broken support unit.

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