TWI413330B - Battery protecting method and system - Google Patents

Abstract

A battery protecting method adapted for preventing a main battery set from being charged and thus damaged by a large current from a load so as to increase the lifetime of the main battery set, includes: providing an auxiliary battery set; determining whether the power of the load is recycled, and entering a charge mode when the power of the load is recycled; and transferring the power from the load to the auxiliary battery set in the charge mode. This method prevents the main battery set from being charged at high C rate and thus damaged, and transfers the damage caused by the large current from the main battery set to the auxiliary battery set. As a result, the reduction of the lifetime of the main battery set is prevented, and the total maintenance cost and difficulty of the two battery sets are reduced because the maintenance cost and difficulty of the auxiliary battery set are lower than that of the main battery set, and only the auxiliary battery set has to be maintained.

Description

Battery protection method and system

The present invention relates to a method and system, and more particularly to a battery protection method and system.

When the electric vehicle is in the vehicle, if the excess kinetic energy can be recovered and converted into electric energy and stored in the battery pack, the endurance of the electric vehicle can be effectively increased, but the disadvantage is: if the electric vehicle is braked, a large current is generated to recover the current directly. Charging the battery pack, the large current recovery will cause the battery pack to be charged at an abnormally high C Rate for a short period of time, resulting in reversible loss and irreversible loss of the battery pack capacity, and reducing the life of the battery pack, so the battery pack must be replaced frequently. And increase maintenance costs.

Accordingly, it is an object of the present invention to provide a battery protection method that avoids the above-described deficiencies.

A battery protection method is suitable for preventing damage to a main battery pack and improving the service life of the main battery pack when charging a large current from a load, and the method comprises the steps of: providing an auxiliary battery pack; determining whether to recover the load Energy, if yes, performing a charging mode; and in the charging mode, transferring energy from the load to the auxiliary battery pack.

Another object of the present invention is to provide a battery protection system that avoids the aforementioned drawbacks.

The battery protection system is coupled between a load and a main battery pack, and is suitable for preventing damage caused by inductive current return from the load to the main battery pack and improving the service life of the main battery pack, including: An auxiliary battery pack for charging and discharging; a first switch coupled between the load and the auxiliary battery pack; a first voltage converter coupled to the main battery pack for receiving the received voltage Performing a conversion to provide a charging current; a second switch coupled between the auxiliary battery and the first voltage converter; and a control circuit for controlling the first switch to be turned on in a charging mode to cause the load to be The auxiliary battery pack is electrically connected to cause the induced current to charge the auxiliary battery pack to transfer energy from the load to the auxiliary battery pack; and the control circuit further controls the second switch to be turned on in a discharge mode The first voltage converter is electrically coupled to the auxiliary battery pack such that the charging current charges the primary battery pack to transfer energy from the secondary battery pack to the primary battery pack.

The effect of the present invention is to prevent large current from being recharged by the load to the battery pack, and to charge the battery pack with a trickle current during non-recharging to provide a charging and maintenance function for the battery pack.

The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments.

As shown in FIG. 1, a preferred embodiment of the battery protection system of the present invention is adapted to be coupled between a main battery pack having a plurality of batteries and an input/output terminal and a load, and is operable in a discharge mode. a charging mode and a balancing mode to prevent damage to the main battery pack during high current recharging and to increase the service life of the main battery pack. In this embodiment, the load is an electric vehicle motor capable of performing acceleration or braking. And the battery protection system comprises: an auxiliary battery pack 2, a first switch 21, a first voltage converter 3, a second switch 32, a second voltage converter 4, a third switch 41 and a control Circuit 5.

The auxiliary battery pack 2 is used for charging and discharging, and has an input and output end.

The first switch 21 is electrically connected between the load and the input and output terminals of the auxiliary battery pack 2, and is controlled to switch between conduction and non-conduction.

The first voltage converter 3 has an output terminal electrically connected to the input and output terminals of the main battery pack and an input terminal for converting the voltage received by the input terminal to provide a charging current.

The second switch 32 is electrically connected between the input and output terminals of the auxiliary battery pack 2 and the input end of the first voltage converter 3, and is controlled to switch between conduction and non-conduction.

The second voltage converter 4 has an output electrically connected to the auxiliary battery pack 2 and an input for converting the voltage received by the input.

The third switch 41 is electrically connected between the input and output terminals of the main battery pack and the input terminal of the second voltage converter 4.

The control circuit 5 causes the battery protection system to perform a battery protection method based on an external command or by detecting a power supply condition of the main battery pack to the load. The battery protection method includes the following steps, as shown in FIG. 2:

Step 10: providing an auxiliary battery pack 2 to the main battery pack;

Step 20: Determine whether to recover the energy of the load, and if so, perform a charging mode, if not, proceed to step 30.

The detailed method of step 10 is: when it is detected that the motor performs braking to generate recyclable energy, then the charging mode is entered.

<Charging mode>

As shown in FIG. 1, when the main battery pack supplies power to the load, and the load generates an induced current, the control circuit performs a charging mode to turn on the first switch 21 to charge the induced current through the first switch 21. To the auxiliary battery pack 2, energy from the load is transferred to the auxiliary battery pack 2.

By using the auxiliary battery pack 2 as a buffer between the load and the main battery pack, it is possible to transfer the damage that may be caused by the recovery current from the main battery pack to the auxiliary battery pack 2, so as to avoid the main battery when the induced current is in a large current state. The group caused damage.

Step 30: Determine whether to execute a discharge mode, and if so, execute the discharge mode, otherwise return to step 20.

<discharge mode>

As shown in FIG. 3, when the main battery pack does not provide energy to the load and is in an idle state, the control circuit 5 performs a discharge mode, so that the first switch 21 and the third switch 41 are not turned on, and the second switch 31 is turned on. The electrical connection between the input of the first voltage converter 3 and the input and output of the auxiliary battery pack 2 is established.

At this time, the first voltage converter 3 converts the output voltage of the auxiliary battery pack 2 into an input voltage corresponding to the main battery pack, transfers energy from the auxiliary battery pack 2 to the main battery pack, and more The output voltage of the auxiliary battery pack 2 is converted into an input voltage corresponding to the main battery pack to generate a charging current to charge the main battery pack, wherein the charging current is sized to cause the main battery pack to be in a trickle charge (trickle The state of charge).

In this embodiment, the first voltage converter 3 is a step-up DC converter that boosts the output voltage from the auxiliary battery pack 2 to an input voltage that matches the main battery pack.

It is further explained here that the maximum capacity of the main battery pack decreases as the number of uses increases, and the reduced capacity includes an irreversible loss and a reversible loss, and the irreversible loss mainly comes from the loss of the active material, and thus cannot be recovered. The reversible loss mainly comes from improper charging and discharging processes (such as large current discharge and high current charging), so that the internal active material arrangement of the battery is not arranged neatly, resulting in a decrease in the recyclable active material, and the internal activity of the battery can be achieved by trickle charging. The material has sufficient time to align when it is migrated to improve reversible loss and slow down the aging of the battery, thereby increasing the life of the main battery pack.

Step 40: Determine whether to perform a balance mode, and if yes, enter the balance mode, otherwise, return to step 20.

<balance mode>

The main battery pack includes a plurality of batteries, wherein the charge and discharge capacity, the charge conversion efficiency, or the initial charge of each battery are not completely the same, so the voltage of each battery may be different after a long period of reverse charging and discharging. At this time, it is necessary to balance the batteries. The control circuit 5 detects the potential of each battery and compares it with a reference potential value to determine whether there is a battery higher than the reference potential value, and if so, performs a balancing mode. Furthermore, the control circuit 5 can also perform this balancing mode based on an external command.

As shown in FIG. 4, in the balanced mode, the control circuit 5 causes the first switch 21 and the second switch 31 to be non-conducting, and the third switch 41 is turned on to establish the input and output terminals of the main battery pack and the second voltage. An electrical connection of the input end of the converter 4, thereby converting the output voltage of the main battery into an input voltage corresponding to the auxiliary battery pack 2 to transfer energy from the battery of the main battery pack higher than the reference potential value to the auxiliary battery pack 2 Until the potential of the batteries is equal to the reference potential value, and the power in the main battery pack is balanced to avoid recharging or discharging again, the main battery pack is caused by overcharge or overdischarge due to the power imbalance. The damage even caused the main battery pack to explode.

In this embodiment, the second voltage converter 4 is a step-down DC converter that steps down the output voltage from the main battery pack to meet the input voltage of the auxiliary battery pack 2.

In summary, the present invention has the following advantages:

1. The method of providing trickle charge to the main battery pack by the auxiliary battery pack 2 to achieve the function of charging and maintaining the main battery pack.

2. The auxiliary battery pack 2 is used as a buffer device between the load and the main battery pack to receive the induced current from the load, and then converted into a small current to be supplied to the battery pack to prevent the induced current value from being in a large current state. The battery pack causes damage, and the damage caused by the induced current can be transferred from the main battery pack to the auxiliary battery pack 2, which not only reduces the life span of the main battery pack, but also improves the maintenance cost and ease of the auxiliary battery pack 2 compared with the main battery pack. It is cheap and easy, and the present invention can shift the maintenance center of the main battery pack to the auxiliary battery pack 2, thereby reducing the maintenance cost and difficulty for the entire battery pack.

3. The power of the battery with higher power in the main battery pack is transferred to the auxiliary battery pack 2 by the control circuit 5 to maintain the balance of the power of each battery in the main battery pack.

The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent.

10‧‧‧Procedures

20‧‧‧Recycling steps

30‧‧‧Steps for discharging

40‧‧‧Steps for balance

2‧‧‧Auxiliary battery pack

21‧‧‧First switch

3‧‧‧First voltage converter

31‧‧‧second switch

4‧‧‧Second voltage converter

41‧‧‧ Third switch

5‧‧‧Control circuit

1 is a circuit diagram of a preferred embodiment of the present invention operating in a charging mode;

Figure 2 is a flow chart of the preferred embodiment;

3 is a circuit diagram of the preferred embodiment operating in a discharge mode; and

4 is a circuit diagram of the preferred embodiment operating in a balanced mode.

2. . . Auxiliary battery pack

twenty one. . . First switch

3. . . First voltage converter

31. . . Second switch

4. . . Second voltage converter

41. . . Third switch

5. . . Control circuit

Claims (13)

A battery protection method is suitable for preventing damage to a main battery pack and improving the service life of the main battery pack when charging a large current from a load, and the method comprises the steps of: providing an auxiliary battery pack; determining whether to recover the load Energy, if yes, performing a charging mode; and in the charging mode, transferring energy from the load to the auxiliary battery pack; when detecting that the primary battery pack does not provide energy to the load and is in an idle state, Then enter a discharge mode to transfer energy from the auxiliary battery pack to the main battery pack. According to the battery protection method of claim 1, the load is a motor capable of performing acceleration or braking, wherein when the motor is detected to perform braking to generate recyclable energy, the charging mode is entered. . According to the battery protection method of claim 1, the load generates an induced current, wherein the induced current is charged to the auxiliary battery pack in the charging mode. According to the battery protection method of claim 1, further comprising: determining whether to perform a discharge mode if the energy of the load is not recovered; and if the discharge mode is performed, the energy from the auxiliary battery pack is Transfer to the main battery pack. The battery protection method according to claim 4, wherein the output voltage of the auxiliary battery pack is further converted into an input voltage corresponding to the main battery pack to perform energy transfer. The battery protection method according to claim 5, wherein the auxiliary battery pack further generates a charging current to charge the main battery pack. The battery protection method according to claim 6, wherein the charging current is in a state that the main battery pack is in a trickle charge state. The battery protection method according to claim 1, further comprising: determining whether to perform a balancing mode; and if performing the balancing mode, transferring energy from the main battery to the auxiliary battery. The battery protection method according to claim 8, wherein the output voltage of the main battery pack is further converted into an input voltage of the auxiliary battery pack to perform energy transfer. According to the battery protection method of claim 8, the main battery pack includes a plurality of batteries, wherein the battery protection method further comprises: detecting a potential of each battery of the main battery pack, and according to a reference potential The values are compared to determine if there is a battery above the reference potential value, and if so, the balancing mode is performed such that the battery above the reference potential value outputs energy. The utility model relates to a battery protection system, which is coupled between a load and a main battery pack, and is suitable for preventing damage caused by inductive current returning from the load to the main battery pack and improving the service life of the main battery pack, including: An auxiliary battery pack for charging and discharging; a first switch coupled between the load and the auxiliary battery pack; a first voltage converter coupled to the main battery pack for receiving the received voltage Performing a conversion to provide a charging current, the charging current is in a trickle charge state; a second switch coupled between the auxiliary battery and the first voltage converter; and a control circuit Controlling the first switch to be turned on in a charging mode to electrically connect the load to the auxiliary battery pack, so that the induced current charges the auxiliary battery pack, and transfers energy from the load to the auxiliary battery pack; The control circuit further controls the second switch to be turned on in a discharge mode to electrically connect the first voltage converter to the auxiliary battery pack, so that the charging current charges the main battery pack. Was transferred to the main power of the auxiliary battery from the battery pack. The battery protection system of claim 11, further comprising: a second voltage converter coupled to the auxiliary battery pack for converting the received voltage; and a third switch coupled to Between the main battery pack and the second voltage converter; And the control circuit further controls the third switch to be turned on in a balanced mode to electrically connect the second voltage converter to the main battery pack, and convert the output voltage of the main battery into an input voltage corresponding to the auxiliary battery pack. Energy from the primary battery pack is transferred to the secondary battery pack. According to the battery protection system of claim 12, the main battery pack includes a plurality of batteries, wherein: the control circuit further detects the potential of each battery of the main battery pack, and compares according to a reference potential value. To determine whether there is a battery higher than the reference potential value, and if so, perform the balancing mode to cause the battery that is higher than the reference potential to output energy.