A conversion system and method for parallel input and output of positive and negative group batteries

Abstract

The present application relates to a kind of positive and negative group battery parallel input and output conversion system and method, it is applied to the special vehicle powered by positive and negative group battery, when needing to keep value or simultaneously charging positive and negative group battery, when needing to keep value or simultaneously charging positive and negative group battery, can be realized by operating the conversion switch on instrument panel, the parallel input and output of positive and negative group battery, simultaneously the load connected to original negative group battery is cut off, guarantee the safety when parallel and avoid the influence to load;When original vehicle main switch is opened alone, the electric equipment on the vehicle can also keep the original vehicle power state unchanged;When conversion switch and main switch are connected simultaneously, only positive group battery is reserved for vehicle power supply, and the safety of positive and negative group battery series and parallel switching is guaranteed by self-locking design.

Description

Technical Field

[0001] This invention belongs to the field of power distribution management and control technology for special vehicles, and specifically relates to a system and method for parallel connection of battery packs. Background Technology

[0002] To meet the power demands of high-power equipment, some special vehicles adopt a 48V power supply system, consisting of positive and negative 24V power sources connected in series. The positive and negative 24V power sources can supply power to the vehicle's 24V electrical equipment, while high-power equipment can also be powered by the series-connected 48V power source. For example... Figure 1 The diagram shows the original vehicle circuit. When the vehicle's main switch is not turned on, the negative terminal of the positive battery is connected to one end of the J1 contactor, and the positive terminal of the negative battery is connected to one end of the J2 contactor. Contactors J1 and J2 are not engaged, and both the positive and negative batteries are in a floating, no-output state; the main distribution box has no power output. When the main switch is turned on, the coils of contactors J1 and J2 are powered by the positive battery, the contactor contacts are engaged, and both the negative terminal of the positive battery and the positive terminal of the negative battery are connected to the vehicle body in series. The main distribution box can provide -24V, 24V, and 48V power supplies.

[0003] However, in actual use, the following problems were found with this power supply circuit: First, in low-temperature environments, a heating monitoring function was added to enable rapid vehicle start-up, but the heater is only powered by the positive battery pack. Due to the limited capacity of the positive battery pack, it cannot support the vehicle's long-term heating monitoring operation and cannot fully utilize the vehicle's actual power supply capacity. Second, the positive battery pack has a higher discharge frequency and depth than the negative battery pack. After the positive and negative batteries are connected in series, it also has a certain impact on the overall output performance of the battery. Third, when the vehicle is charging, the positive and negative batteries need to be charged separately, which takes a long time. The charging device is not compatible with other vehicle models, which affects the equipment's support performance. Summary of the Invention

[0004] In view of this, the present invention proposes a conversion system and method for parallel input and output of positive and negative battery packs. By adding a conversion device, the present invention can safely and conveniently achieve output conversion in the series-parallel configuration of positive and negative battery packs using only an operating switch.

[0005] The specific technical solution is as follows:

[0006] A parallel input / output conversion system for positive and negative battery banks is applied to special vehicles powered by positive and negative battery banks. The system includes an instrument panel, contactors J1 and J2. The instrument panel has a main switch that controls contactors J1 and J2. J1 connects the negative terminal of the positive battery bank to the vehicle body, and J2 connects the positive terminal of the negative battery bank to the vehicle body. When the main switch is closed, the positive and negative batteries are connected in series. A conversion switch is added to the instrument panel for parallel connection of the positive and negative batteries. A conversion device is also added to achieve parallel connection of the positive and negative batteries. The conversion device includes a grid-connected contactor CJ1, a grid-connected contactor CJ2, a negative battery bank contactor CJ3, a main switch relay CJ4, and a conversion relay CJ5.

[0007] Furthermore, the main switch relay CJ4 is used to control the grid-connected contactor CJ1 (1) and the grid-connected contactor CJ2 (2), enabling the positive and negative battery groups to switch between parallel and series states.

[0008] Furthermore, the changeover relay CJ5 is used to control the grid-connected contactor CJ2 and the negative group contactor CJ3, thereby controlling the connection status of the positive and negative terminals of the negative group battery.

[0009] Furthermore, the main switch relay CJ4 and the changeover relay CJ5 are connected in series with their contacts in the same coil.

[0010] Furthermore, grid connection contactor CJ1 and grid connection contactor CJ2 are used to connect the positive and negative battery groups to the grid, while negative group contactor CJ3 is used to control the negative terminal output of the negative battery group.

[0011] Furthermore, multiple freewheeling diodes are provided, with CJ1, CJ2, CJ3, CJ4, and CJ5 connected in parallel with the freewheeling diodes to provide a discharge circuit for the self-induced electromotive force generated by the relays and contactors when they are turned on or off; a reverse connection protection diode is provided between the instrument panel and the switching device to suppress reverse current.

[0012] A method for parallel input and output of positive and negative battery banks is disclosed. When the main switch is open and a newly added transfer switch is turned on, the negative battery bank is connected in parallel to both ends of the positive battery bank, while the load connected to the original negative battery bank is disconnected. The working process is as follows: the main switch relay CJ4 is not working, and its contacts are normally closed. The transfer switch output is to the grid connection 1 contactor CJ1, and the CJ1 contactor is turned on, connecting the positive terminal of the negative battery bank to the positive terminal of the positive battery bank. The transfer switch output is to the grid connection 2 contactor CJ2, and the CJ2 contactor is turned on, connecting the negative terminal of the positive battery bank to the negative terminal of the negative battery bank. The transfer switch output is to the transfer relay CJ5, and CJ5 is working, and its normally closed contacts are open. The negative battery bank 1 contactor CJ3 is turned off, and the negative output of the negative battery bank is disconnected. When the main switch is open, J1 and J2 are disconnected, and the negative terminal of the positive battery bank is disconnected from the vehicle body, and the positive terminal of the negative battery bank is disconnected from the vehicle body.

[0013] Furthermore, both the positive and negative batteries power the heater.

[0014] Furthermore, when the newly added transfer switch is disconnected and the main switch is switched on independently, the operation of the electrical equipment on the vehicle remains unchanged from the original model. The operation process is as follows: the main switch outputs to J1, the J1 contactor is closed, and the negative terminal of the positive battery is connected to the vehicle body; the CJ5 contactor is not working, and its contacts are normally closed, the main switch outputs to the J2 contactor coil, the J2 contactor is closed, and the positive terminal of the negative battery is connected to the vehicle body; the main switch outputs to CJ3, the CJ3 contactor is working, and its contacts are closed, and the negative terminal of the negative battery is output to the -24V distribution box; the main switch outputs to CJ4, the CJ4 contactor is working, and its contacts are open, and CJ1 and CJ2 are disconnected; the positive terminal of the positive battery is output to the +24V distribution box, and the positive and negative batteries are in series, with the distribution box outputting positive and negative 24V.

[0015] Furthermore, when the main switch is turned on and the changeover switch is turned on, contactor J1 is turned on, connecting the negative terminal of the positive battery to the vehicle body; contactor J2 is not working, disconnecting the positive terminal of the negative battery from the vehicle body; contactors CJ4 and CJ5 are working, disconnecting their contacts; contactors CJ1, CJ2, and CJ3 are not working; the positive terminal of the positive battery is output to the main distribution box, and the negative terminal of the negative battery is disconnected, leaving only the positive battery to power the vehicle.

[0016] Beneficial effects

[0017] 1. Through this invention, when the new conversion switch is turned on separately, the negative battery is connected in parallel to both ends of the positive battery, and the positive and negative batteries can jointly power the heater. At the same time, the load connected to the original negative battery is disconnected, ensuring safety during parallel connection and avoiding the impact on the load of the negative battery.

[0018] 2. Through this invention, when the original vehicle's main switch is turned on separately, the operation of the vehicle's electrical equipment can remain unchanged from the original vehicle model.

[0019] 3. Through this invention, when the changeover switch or the main switch is turned on by one of them, and another switch is turned on due to misoperation, both the positive and negative batteries are disconnected. The self-locking design ensures the safety of the series-parallel switching of the positive and negative batteries.

[0020] 4. With this invention, after the two switches are turned on, turning off either switch will automatically execute the currently held operation, thus satisfying the occupant's final operational intention.

[0021] 5. The newly added control circuit does not affect the original vehicle's working functions and performance, and can also meet the usage requirements of heating monitoring and parallel charging, ensuring safety while improving the vehicle's low-temperature starting performance, charging rate and protection performance.

[0022] 6. The newly added control circuit of this invention does not affect the original vehicle's working functions and performance, and can also meet the usage requirements of heating monitoring and parallel unified charging, ensuring the safety of use while improving the vehicle's low-temperature starting performance, charging rate and protection performance. Attached Figure Description

[0023] Figure 1 Diagram illustrating the working principle of the original vehicle's positive and negative battery packs.

[0024] Figure 2 This diagram illustrates the working principle of parallel input and output of positive and negative groups. Detailed Implementation

[0025] This invention provides a parallel input and output system and method for positive and negative battery packs. The parallel input and output method is applied to special vehicles powered by positive and negative battery packs. These special vehicles require an additional switch on the dashboard for parallel operation of the positive and negative battery packs. A conversion device is also required to achieve the parallel connection. The connections of interfaces X1 and X2 in the dashboard to the original circuit remain unchanged. A new interface X3 is added. Interface X2 outputs a control signal in parallel, which, along with interface X3, connects to interface X1 of the conversion device, outputting the switch control signal to the conversion device. The newly added interface X2 in the conversion device connects to the main distribution box, providing a -24V power output. The newly added interfaces X3, X4, X5, and X6 in the conversion device are connected to the positive and negative terminals of the positive and negative battery packs, respectively, to achieve output conversion of the positive and negative battery packs.

[0026] The original vehicle's dashboard has been upgraded with a new conversion device, which mainly enables the positive battery pack to be connected in parallel with the negative battery pack.

[0027] The switching device includes grid-connected contactor CJ1 (1), grid-connected contactor CJ2 (2), negative group contactor CJ3 (1), main switch relay CJ4, and switching relay CJ5.

[0028] Among them, the main switch relay CJ4 in the conversion device mainly realizes the control of grid-connected contactor CJ1 and grid-connected contactor CJ2, so that the positive and negative batteries switch between parallel and series states.

[0029] The changeover relay CJ5 mainly controls the grid-connected contactor CJ2 (2nd contactor) and the negative group contactor CJ3 (1st contactor), controlling the connection status of the positive and negative terminals of the negative group battery.

[0030] The main switch relay CJ4 and the changeover relay CJ5 use a series connection of their contacts and coils, meaning that the external connections of these two relays are all connected in series between their respective contacts and the coils of the other relay. This means that if one contact is disconnected, the control line of the other relay's coil is also disconnected. This is mainly to achieve mutual exclusion between the main switch relay CJ4 and the changeover relay CJ5, preventing simultaneous operation of the switches and avoiding short circuit faults in the positive and negative battery caused by the switching of the grid-connected contactor 1 CJ1, grid-connected contactor 2 CJ2, and negative group 1 contactor CJ3. It also allows for the use of only performing the current operation.

[0031] The grid connection contactor CJ1 and grid connection contactor CJ2 are mainly used to connect the positive and negative battery packs to the grid.

[0032] The negative group 1 contactor CJ3 mainly realizes the negative terminal output control of the negative group battery to prevent the negative group batteries from affecting the -24V load after being connected in parallel.

[0033] The freewheeling diodes D1, D2, D3, D4, and D5 mainly provide a discharge circuit for the self-induced electromotive force generated when the relay and contactor are turned on or off, so as to avoid the influence of reverse electromotive force on other circuits or components; the reverse connection protection diodes D6 and D7 mainly suppress reverse current and prevent reverse current from affecting the control circuit.

[0034] This system operates in two normal states: First, the selector switch is turned on and the main switch is turned off, achieving parallel connection of the positive and negative battery banks; second, the selector switch is turned off and the main switch is turned on, maintaining the original vehicle connection state. Figure 1 The connection status is that of the main switch is turned on. In addition, considering practical operating conditions, it is possible that both the transfer switch and the main switch may be turned on. To ensure the safety and stability of the system, this invention is designed with a working mode for this extreme situation.

[0035] When the main switch is off and the newly added transfer switch is turned on separately, the negative battery is connected in parallel to the two ends of the positive battery, and the load connected to the original negative battery is disconnected. The working process is as follows: the main switch relay CJ4 is not working, and the contacts are normally closed. The transfer switch output is to the grid connection 1 contactor CJ1. Contactor CJ1 is turned on, and the positive terminal of the negative battery is connected to the positive terminal of the positive battery. The transfer switch output is to the grid connection 2 contactor CJ2. Contactor CJ2 is turned on, and the negative terminal of the positive battery is connected to the negative terminal of the negative battery. The transfer switch output is to the transfer relay CJ5. CJ5 is working, and the normally closed contact is opened. Contactor CJ3 of negative battery 1 is turned off, and the negative output of the negative battery is disconnected. When the main switch is off, J1 and J2 are disconnected, and the negative terminal of the positive battery is disconnected from the vehicle body, and the positive terminal of the negative battery is disconnected from the vehicle body.

[0036] When the newly added transfer switch is disconnected and the main switch is switched on alone, the operation of the electrical equipment on the vehicle remains unchanged from the original model. The operation process is as follows: the main switch outputs to J1, the J1 contactor is closed, and the negative terminal of the positive battery is connected to the vehicle body; the CJ5 contactor is not working, and the contacts are normally closed, the main switch outputs to the J2 contactor coil, the J2 contactor is closed, and the positive terminal of the negative battery is connected to the vehicle body; the main switch outputs to CJ3, the CJ3 contactor is working, and the contacts are closed, and the negative terminal of the negative battery is output to the -24V distribution box; the main switch outputs to CJ4, the CJ4 contactor is working, and the contacts are open, and CJ1 and CJ2 are disconnected; the positive terminal of the positive battery is output to the +24V distribution box, and the positive and negative batteries are in series, with the distribution box outputting positive and negative 24V.

[0037] When the main switch and the changeover switch are both on, contactor J1 is on, connecting the negative terminal of the positive battery to the vehicle body; contactor J2 is off, disconnecting the positive terminal of the negative battery from the vehicle body; contactors CJ4 and CJ5 are on, disconnecting their contacts; contactors CJ1, CJ2, and CJ3 are off; the positive terminal of the positive battery is output to the main distribution box, and the negative terminal of the negative battery is off, leaving only the positive battery to power the vehicle.

[0038] The following is a detailed explanation of the various states based on the sequence of switch actions:

[0039] Step 1: Close the main switch on the dashboard. One positive battery output goes to the J1 contactor coil, J1 contactor is energized, and the negative terminal of the positive battery is connected to the vehicle body. Another positive battery output goes to the J2 contactor coil through diode D6 and the closed contact of the transfer relay CJ5, J2 contactor is energized, and the positive terminal of the negative battery is connected to the vehicle body. A third positive battery output goes to the negative battery 1 contactor coil CJ3 through diode D6, CJ3 is energized, and the negative terminal of the negative battery is output to the distribution box, which outputs both +24V and -24V. This maintains the original vehicle main switch's power-on function.

[0040] Step 2: Disconnect the main switch on the dashboard. J1, J2, and CJ3 are all inactive, and the positive and negative battery groups are not connected. Turn on the transfer switch. One positive battery outputs through diode D7 and the closed contact of the main switch relay CJ4 to the coils of parallel contactors CJ1 and CJ2. CJ1 and CJ2 are engaged, connecting the positive and negative terminals of the positive and negative batteries. The positive and negative batteries are connected in parallel and output to the +24V main distribution box; there is no -24V output. This system enables heating and parallel charging of the positive and negative batteries and shields the negative battery group from any impact on -24V equipment.

[0041] Step 3: Turn on the main switch on the instrument panel, then turn on the transfer switch. The positive terminal of one positive battery is output to the coil of transfer relay CJ5 through diode D7. CJ5 is disconnected, contactor J2 is disconnected, and the positive terminal of the negative battery is disconnected from the vehicle body. Contactor CJ3 of the negative battery is disconnected, and the negative terminal of the negative battery is disconnected from the -24V output of the main distribution box. The contacts of contactors CJ1, CJ2, and CJ3 are all open. At this time, contactor J1 is energized, and only the positive battery output is sent to the main distribution box, which can avoid short circuit faults caused by the series-parallel switching of the positive and negative batteries.

[0042] Step 4: Turn on the transfer switch and then the main switch. The positive terminal of one positive battery group is output to the coil of the main switch relay CJ4 through diode D6. CJ4 is disconnected, and the parallel contactors CJ1 and CJ2 are disconnected. The positive terminal of the positive battery group is disconnected from the positive terminal of the negative battery group, and the negative terminal of the negative battery group is disconnected from the negative terminal of the positive battery group. The contacts of contactors CJ1, CJ2, and CJ3 are all open. At this time, contactor J1 is energized, and only the positive battery group outputs to the main distribution box, which can avoid short circuit faults caused by the series-parallel switching of the positive and negative batteries.

[0043] Step 5: Turn on the transfer switch, then turn on the main switch, and then turn off the main switch. The main switch relay CJ4 changes from the off state to the energized state, and contactors CJ1 and CJ2 are connected, connecting the positive terminals of the positive battery pack to the positive terminals of the negative battery pack, and connecting the negative terminals of the positive battery pack to the negative terminals of the negative battery pack. Contactor J1 changes from the energized state to the off state, disconnecting the negative terminal of the positive battery pack from the vehicle body. The positive and negative batteries are connected in parallel and output to the +24V main distribution box. This can perform the transfer switch operation function, while avoiding short-circuit faults in the series-parallel connection conversion of the positive and negative batteries. When one operation is turned off, it can automatically switch back to the currently maintained operation, realizing the functions of heating and parallel charging of the positive and negative batteries.

[0044] Step 6: Turn on the transfer switch, then turn on the main switch, and then turn off the transfer switch. The transfer relay CJ5 changes from the off state to the energized state, and the contactor CJ3 is energized. The negative terminal of the negative battery is output to the -24V of the main distribution box; the J1 and J2 contactors are energized, and the positive terminal of the negative battery is connected to the negative terminal of the positive battery through the vehicle body. Both +24V and -24V are output from the distribution box. It can perform the main switch operation function, while avoiding short circuit faults in the series-parallel connection conversion of the positive and negative batteries. When one operation is turned off, it can automatically switch back to the currently maintained operation to achieve +24V and -24V output.

[0045] Step 7: Turn on the main switch, then turn on the transfer switch, and then turn off the transfer switch. The transfer relay CJ5 changes from the off state to the energized state, and the contactor CJ3 is energized. The negative terminal of the negative battery outputs -24V to the main distribution box; the contactors J1 and J2 are energized, and the positive terminal of the negative battery is connected to the negative terminal of the positive battery through the vehicle body. Both +24V and -24V are output from the distribution box. This can perform the main switch operation function, while avoiding short-circuit faults caused by the series-parallel connection conversion of the positive and negative batteries. When one operation is turned off, it can automatically switch back to the currently maintained operation to achieve +24V and -24V output.

[0046] Step 8: Turn on the main switch, then turn on the transfer switch, and then turn off the main switch. The main switch relay CJ4 changes from the off state to the energized state, and contactors CJ1 and CJ2 are connected, connecting the positive terminals of the positive battery pack to the positive terminals of the negative battery pack, and connecting the negative terminals of the positive battery pack to the negative terminals of the negative battery pack. Contactor J1 changes from the energized state to the off state, disconnecting the negative terminal of the positive battery pack from the vehicle body. The positive and negative batteries are connected in parallel and output to the +24V main distribution box. This can perform the transfer switch operation function, while avoiding short-circuit faults in the series-parallel connection conversion of the positive and negative batteries. When one operation is turned off, it can automatically switch back to the currently maintained operation, realizing the functions of heating and parallel charging of the positive and negative batteries.

[0047] This invention is applied to special vehicles powered by positive and negative battery packs. By adding a changeover switch and a conversion device, the positive and negative battery packs can be connected in parallel for input and output without changing the original vehicle operation, functions, or performance. When both switches are working simultaneously, the current operation can be automatically executed, avoiding short-circuit faults during the series-parallel connection of batteries, and the parallel connection of the negative battery pack will not affect the original -24V electrical equipment.

Claims

1. A method for parallel input and output of positive and negative batteries, characterized in that: A conversion system based on parallel input / output of positive and negative battery banks is applied to special vehicles powered by positive and negative battery banks. The system includes an instrument panel, contactors J1 and J2. The instrument panel has a main switch that controls contactors J1 and J2. J1 connects the negative terminal of the positive battery bank to the vehicle body, and J2 connects the positive terminal of the negative battery bank to the vehicle body. When the main switch is closed, the positive and negative batteries are connected in series. A conversion switch is added to the instrument panel for parallel operation of the positive and negative batteries. A conversion device is added to realize the parallel connection of the positive and negative batteries. The conversion device includes a grid-connected contactor CJ1, a grid-connected contactor CJ2, a negative battery bank contactor CJ3, a main switch relay CJ4, and a conversion relay CJ5. The main switch relay CJ4 is used to connect the grid-connected contactor CJ1 and the negative battery bank in series. The control of contactor CJ2 for grid 2 allows switching between parallel and series connection of the positive and negative battery groups; transfer relay CJ5 controls contactor CJ2 for grid 2 and contactor CJ3 for negative group 1, controlling the connection status of the positive and negative terminals of the negative battery group; main switch relay CJ4 and transfer relay CJ5 are connected in series with their contacts on the same coil; contactor CJ1 for grid 1 and contactor CJ2 for grid 2 are used to connect the positive and negative battery groups to the grid, and contactor CJ3 for negative group 1 is used to control the negative terminal output of the negative battery group; multiple freewheeling diodes are installed, with CJ1, CJ2, CJ3, CJ4, and CJ5 connected in parallel with the freewheeling diodes to provide a discharge circuit for the self-induced electromotive force generated when the relays and contactors are turned on or off; a reverse connection protection diode is installed between the instrument panel and the switching device to suppress reverse current; When the main switch is off and the newly added transfer switch is turned on separately, the negative battery is connected in parallel to the two ends of the positive battery, and the load connected to the original negative battery is disconnected. The working process is as follows: the main switch relay CJ4 is not working, and the contacts are normally closed. The transfer switch output is to the grid connection 1 contactor CJ1. Contactor CJ1 is turned on, and the positive terminal of the negative battery is connected to the positive terminal of the positive battery. The transfer switch output is to the grid connection 2 contactor CJ2. Contactor CJ2 is turned on, and the negative terminal of the positive battery is connected to the negative terminal of the negative battery. The transfer switch output is to the transfer relay CJ5. CJ5 is working, and the normally closed contact is opened. Contactor CJ3 of negative battery 1 is turned off, and the negative output of the negative battery is disconnected. When the main switch is off, J1 and J2 are disconnected, and the negative terminal of the positive battery is disconnected from the vehicle body, and the positive terminal of the negative battery is disconnected from the vehicle body.

2. The method for parallel input and output of positive and negative battery packs according to claim 1, characterized in that: The positive and negative batteries work together to power the heater.

3. The method for parallel input and output of positive and negative battery packs according to claim 1, characterized in that: When the newly added transfer switch is disconnected and the main switch is switched on alone, the operation of the electrical equipment on the vehicle remains unchanged from the original model. The operation process is as follows: the main switch outputs to J1, the J1 contactor is closed, and the negative terminal of the positive battery is connected to the vehicle body; CJ5 is not working, the contacts are normally closed, the main switch outputs to the J2 contactor coil, the J2 contactor is closed, and the positive terminal of the negative battery is connected to the vehicle body; the main switch outputs to CJ3, the CJ3 contactor is working, the contacts are closed, and the negative terminal of the negative battery is output to the -24V distribution box; the main switch outputs to CJ4, CJ4 is working, the contacts are open, and CJ1 and CJ2 are disconnected; the positive terminal of the positive battery is output to the +24V distribution box, and the positive and negative batteries are in series, with the distribution box outputting positive and negative 24V.

4. The method according to any one of claims 1-2, characterized in that: When the main switch and the changeover switch are both on, contactor J1 is on, connecting the negative terminal of the positive battery to the vehicle body; contactor J2 is off, disconnecting the positive terminal of the negative battery from the vehicle body; contactors CJ4 and CJ5 are on, disconnecting their contacts; contactors CJ1, CJ2, and CJ3 are off; the positive terminal of the positive battery is output to the main distribution box, and the negative terminal of the negative battery is off, leaving only the positive battery to power the vehicle.

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