TWM511156U - Compulsory charging and protective circuit for secondary battery after being over discharged - Google Patents

Abstract

A compulsory charging and protective circuit for secondary battery after being over discharged is disclosed. The circuit includes a circuit conducting switch, a releasing unit, a triggering unit and a comparing unit. When the secondary battery is over discharged, a temporary electrical connection is provided by the present invention. The loop of the secondary battery and a charger keeps. When the secondary battery recovers from abnormal status, the temporary electrical connection is called off so that the secondary battery can keep normal operation. Thus, when the secondary battery is under over-discharge, it doesn't have to be unloaded for repair to settle the issue. Maintenance costs can be saved.

Description

Forced charging protection circuit for overdischarging of secondary battery

The present invention relates to a forced charging protection circuit, and more particularly to a forced charging protection circuit for overdischarging a secondary battery.

Secondary batteries, also known as rechargeable batteries, are widely used in many products, such as notebook computers, tablet computers, mobile phones, and even large electric vehicles and robots. Although the secondary battery is often composed of a rechargeable battery cell string or in parallel, there are different output current and power specifications depending on the power supply target.

Since each of the battery cells has different characteristics at the time of composing the secondary battery, there is a problem that the battery cells are unbalanced regardless of charging or discharging when the secondary battery is used. Abnormal operation can cause the temperature of the secondary battery to rise, reducing the service life of the battery and even causing an explosion. Among them, the cause of the decrease in the service life of the secondary battery is mainly the operation of overcharging or overdischarging. Therefore, a battery management chip is installed in a general secondary battery to solve the above problems.

Please refer to FIG. 1 , which illustrates the structure of a conventional secondary battery 1 including a battery management wafer 2 . The main storage and supply source of the secondary battery 1 power is a plurality of battery cells 3 connected in series. The battery management chip 2 is connected to the battery cell group 3, and the state of each battery cell 3 can be effectively detected, thereby dynamically balancing the battery cells 3. Further, the battery management chip 2, the charge control switch 4, and the discharge control switch 5 constitute a charge and discharge protection circuit. The charging control switch 4 and the discharge control switch 5 are each composed of a field effect transistor and a parasitic diode. The protection circuit is further connected to a terminal unit 6. The terminal unit 6 has a positive terminal 6a, a negative terminal 6b and an information transmission terminal 6c. The terminal unit 6 can be in the form of a socket that looks at the connected object and decides whether to charge or discharge. The battery management chip 2 can transmit the state of the battery cell 3 to the control system outside the secondary battery 1 via the information transmission terminal 6c, or receive the indication from the control system via the information transmission terminal 6c to manage the battery cell 3.

When the object connected to the terminal unit 6 is a charger, current flows to the battery cell 3 via the positive terminal 6a, sequentially passes through the discharge control switch 5 and the charge control switch 4, and finally passes through the negative terminal 6b to flow back to the charger. At this time, the charge control switch 4 and the discharge control switch 5 are maintained in an open state, and the battery management chip 2 knows the direction of the current by the resistor 7, thereby knowing that it is currently in a charged state. When the object connected to the terminal unit 6 is a load, the current flows from the battery core 3 to the load via the positive terminal 6a; the load also has current flowing through the negative terminal 6b, the charging control switch 4 and the discharge control switch 5, and flows back to the battery. Core 3, complete the loop. Charge control at this time The switch 4 and the discharge control switch 5 are also in an open state. The battery management chip 2 is also in the direction of the current of the resistor 7, knowing that it is currently in a discharged state.

When the secondary battery 1 is charging, if the overcharge condition is encountered (that is, the voltage of the secondary battery 1 exceeds the rated maximum voltage value during charging), the battery management chip 2 turns off the charging control switch 4, The secondary battery 1 is protected from being damaged by continued charging; similarly, when the secondary battery 1 is discharging, if overdischarge is encountered (that is, the voltage of the secondary battery 1 is lower than the minimum allowable voltage during discharge) At the time of the value, the battery management wafer 2 turns off the discharge control switch 5, and the secondary battery 1 is protected from being unable to recover the chargeability due to continued discharge. When the overcharge protection is performed, since the voltage of the secondary battery 1 decreases with time, when the highest voltage value is lower than the rate, the battery management wafer 2 can turn on the charging control switch 4 again, and the secondary battery 1 resumes normal operation. However, when the overdischarge protection is performed, since the voltage of the secondary battery 1 is unlikely to return to the normal operation voltage, the secondary battery 1 cannot be returned to the normal operation unless the recovery operation is forcibly performed outside the battery.

For consumers, if they use the secondary battery to have over-discharge protection and cannot return to normal operation, they must think that the secondary battery is damaged and require the manufacturer to return the goods; even if the manufacturer is willing to replace the available secondary batteries, this is The cost of shipping once again caused the loss of the manufacturer. Therefore, how to effectively restart the secondary battery after the over-discharge protection of the secondary battery is effective, and the related circuit design needs to be developed.

This paragraph of text extracts and compiles certain features of this creation. Other features will be revealed in subsequent paragraphs. The intention is to cover various modifications and similar arrangements in the spirit and scope of the appended claims.

In order to solve the above problems, the present invention provides a forced charge protection circuit for overdischarging a secondary battery. The circuit comprises: a circuit conduction switch connected in parallel with a charging control switch and a discharge control switch connected in series in a secondary battery to be electrically connected to the two ends; a release unit for receiving a release After the voltage is turned on, a trigger unit is connected to the circuit conduction switch and the release unit for connecting the conduction circuit to the release unit after receiving a trigger signal; and a comparison unit electrically connected to the a secondary battery, comparing a voltage difference between a positive electrode and a negative electrode of the secondary battery and a minimum allowable voltage value; when the voltage difference is greater than a minimum allowable voltage value, providing a normal voltage to the release unit; when the voltage difference is less than a minimum allowable voltage At the time of the value, a release voltage is supplied to the release unit. When the release unit is turned on and the trigger unit turns on the electrical connection between the circuit conduction switch and the release unit, the circuit conduction switch is turned on.

According to the concept of the present invention, the trigger unit is further connected to a trigger switch, and the trigger signal is sent to the trigger unit when the trigger switch is turned on.

According to the concept of the present invention, the trigger unit is a controlled rectifier.

According to the concept of the present invention, a gate of the step-controlled rectifier is connected to the trigger switch, and when the trigger switch is turned on, the gate receives a high potential voltage.

According to the present invention, the forced charge protection circuit further includes a power source connected to the circuit conduction switch for providing power required for the circuit to operate the switch.

According to the present concept, the comparison unit is a comparator.

According to the present invention, an input of the comparator is connected to a circuit signal source of the secondary battery.

According to the present concept, the circuit signal source is a discharge control switch pin or an operating voltage pin (VDD) of the battery management chip of the secondary battery.

According to the present invention, the release unit includes a potent transistor and a parasitic diode.

According to the present concept, the circuit conduction switch is an optical coupling relay.

The present invention provides a temporary electrical connection in the case of over-discharging of the secondary battery, keeping the loop of the secondary battery and the charger continuously; and when the secondary battery returns to the working state, cancels the temporary electrical connection, so that the second time The battery is still operating normally. This makes it possible for the secondary battery to solve the problem in the event of an overdischarge condition without having to be unloaded from the work place, thereby reducing the cost of maintenance.

1‧‧‧Secondary battery

2‧‧‧Battery Management Wafer

3‧‧‧ battery core

4‧‧‧Charging control switch

5‧‧‧Discharge control switch

6‧‧‧ Terminal Unit

6a‧‧‧ positive end

6b‧‧‧Negative end

6c‧‧‧Information transmission end

7‧‧‧resistance

100‧‧‧Secondary battery

100a‧‧‧ nodes

100b‧‧‧ nodes

100c‧‧‧ nodes

100d‧‧‧ nodes

110‧‧‧ battery core

120‧‧‧Battery Management Wafer

121‧‧‧Working voltage pin

122‧‧‧ Grounding Pin

123‧‧‧Charging control switch pin

124‧‧‧Discharge control switch pin

125‧‧‧Battery signal pin

127‧‧‧resistance

130‧‧‧Charging control switch

140‧‧‧Discharge control switch

150‧‧‧terminal unit

150a‧‧‧ positive end

150b‧‧‧Negative end

150c‧‧‧ signal end

200‧‧‧Forced charging protection circuit

210‧‧‧Circuit conduction switch

220‧‧‧ release unit

230‧‧‧Trigger unit

240‧‧‧Comparative unit

250‧‧‧Trigger switch

260‧‧‧Power supply

261‧‧‧Power circuit

FIG. 1 illustrates a conventional secondary battery architecture.

Fig. 2 is a secondary battery to which a forced charging protection circuit is connected in accordance with the present invention.

Figure 3 shows the architecture of the forced charge protection circuit.

Figure 4 illustrates the trigger unit and release unit in the forced charge protection circuit.

Figure 5 illustrates the comparison unit in the forced charge protection circuit.

Figure 6 is a timing chart of some of the components of the forced charge protection circuit.

This creation will be more specifically described by reference to the following embodiments.

Referring to Figures 2 through 6, the embodiments of the present invention are illustrated by the drawings. A forced charge protection circuit 200 in accordance with the present teachings is illustrated in FIG. The forced charge protection circuit 200 is connected to one secondary battery 100. Before the forced charge protection circuit 200 is explained, the secondary battery 100 to which the forced charge protection circuit 200 can be applied will be described.

Commercially available secondary batteries can be classified into a wide variety of types depending on their constituent elements and application targets. The secondary battery used in this creation, regardless of the material and specifications of the battery cell in which it is stored (preferably Ni-Cd, Ni-MH, Li-ion) Lithium polymer battery (Li-polymer) must have a battery management chip for managing the secondary battery. In addition, the battery management chip is capable of overcharging or overdischarging the secondary battery, that is, the secondary battery is subjected to overcharge and overdischarge, and the battery management chip can stop the operation of the secondary battery. Therefore, in the description of FIG. 2, the structure of the secondary battery 100 mainly includes a plurality of them in series and/or Or a battery cell 110 connected in parallel, a battery management chip 120 meeting the above requirements, a charging control switch 130, a discharge control switch 140, and a terminal unit 150.

When the secondary battery 100 is in operation, the charge control switch 130 and the discharge control switch 140 are both in an open state for current to pass. When the object connected to the terminal unit 150 is a charging power source (not shown), the current flows through a positive terminal 150a, sequentially through the battery cell 110 group, the discharge control switch 140 and the charging control switch 130, and finally flows from a negative terminal 150b. Back to the charging power source, at this time, each battery cell 110 is charged; when the object connected to the terminal unit 150 is a load (not shown), the current flows from the negative terminal 150b to the charging control switch 130 and the discharge control switch 140 in sequence. The battery cells 110 are finally returned to the load by the positive terminal 150a, at which time each of the cells 110 is discharged. The battery management wafer 120 can determine whether the secondary battery 100 is discharging or charging by the direction of the current flowing through the resistor 127.

Battery management die 120 has a number of pins. The operating voltage pin (VDD) 121 is connected to a node 100a on the charge and discharge circuit. Since the node 100a is close to the positive terminal of the battery cell group 110, the high potential energy of the bank 110 group end can be obtained. In contrast, the ground terminal pin (VSS) 122 is connected to the other node 100b on the charge and discharge circuit. Since the node 100b is close to the negative terminal of the battery cell group 110, the low potential energy of the group end of the battery cell 110 can be obtained. The difference between the high potential energy and the low potential energy is approximately the current operating voltage of the secondary battery 100. The charge control switch pin 123 and the discharge control switch pin 124 are used to turn the charge control switch 130 and the discharge control switch 140 on or off, respectively. When the secondary battery 100 is operating normally, Both the charge control switch pin 123 and the discharge control switch pin 124 are open. The battery signal pin 125 is used to transmit the state of the battery to a device (not shown) connected to the signal terminal 150c of the terminal unit 150, or to receive an instruction from the device to perform the operation of the secondary battery 100.

The forced charge protection circuit 200 is only connected to the secondary battery 100 when the secondary battery 100 is normally operated, and has no effect; the forced charge protection circuit 200 functions only when the secondary battery 200 encounters an overdischarge condition. The forced charge protection circuit 200 is composed of a circuit conduction switch 210, a release unit 220, a trigger unit 230, a comparison unit 240, a trigger switch 250 and a power supply 260. The circuit-on switch 210 is connected in parallel with the two ends of the charge control switch 130 and the discharge control switch 140 connected in series in the secondary battery 100, that is, electrically connected to the nodes 100c and 100d in FIG. When the circuit conduction switch 210 is turned on, electrical conduction is generated between the nodes 100c and 100d (two ends). The circuit conduction switch 210 can be a commonly used electronic type switch, preferably an optical coupling relay. The power supply 260 is coupled to the circuit conduction switch 210 for providing the power required to operate the circuit conduction switch 210. There is a power supply circuit 261 between the power supply 260 and the circuit-on switch 210 to complete the connection of the power to the circuit-on switch 210. Preferably, the power supply circuit 261 has a design to prevent battery power from flowing back to protect the power supply 260.

The release unit 220 is configured to conduct ground after receiving a release voltage, and when receiving a normal voltage, the release unit 220 blocks ground. In fact, the normal voltage can be any voltage value that is different from the release voltage error range, and the release unit 220 is an electronic switch. Release unit as shown in Figure 4 220 is a switch composed of a field effect transistor and a parasitic diode, the gate of which is electrically connected to the comparison unit 240, and the opening and closing of the release unit 220 is controlled by the comparison unit 240. The trigger unit 230 is connected to the circuit conduction switch 210 and the release unit 220 for electrically connecting the switch 210 to the release unit 220 after receiving a trigger signal. In this embodiment, the trigger unit 230 is a pilot rectifier. For convenience of control, the trigger unit 230 is further connected to a trigger switch 250 that is turned off when the secondary battery 100 is operating normally. When the trigger switch 250 is turned on, the aforementioned trigger signal is sent to the trigger unit 230. The trigger switch 250 can be a general push button switch manually controlled by a person; the trigger switch 250 can also be an electronic switch that is turned on by setting a specific event, such as the secondary battery 100 stops working due to overdischarge 30 minute. The gate of the voltage controlled rectifier is connected to the trigger switch 250. When the trigger switch 250 is turned on, the gate receives a high potential voltage, that is, a trigger signal. When the release unit 220 is turned on, and the trigger unit 230 turns on the electrical connection between the circuit-on switch 210 and the release unit 220, the circuit-on switch 210 is turned on.

The comparison unit 240 is electrically connected to the secondary battery 100, and can compare the voltage difference between the positive electrode and the negative electrode of the secondary battery 100, that is, the operating voltage of the secondary battery 100, and the magnitude of a minimum allowable voltage value. When the voltage difference is greater than the minimum allowable voltage value, a normal voltage is supplied to the release unit 220; when the voltage difference is less than the minimum allowable voltage value, a release voltage is supplied to the release unit 220. In practice, comparison unit 240 can be a comparator, see Figure 5. Comparator When the operating voltage is received (please note that the operating voltage of the secondary battery 100 is not the same as the operating voltage of the forced charging protection circuit 200) and the ground, there are two input terminals and one output terminal. The minimum allowable voltage value is a standard for evaluating the overdischarge of the secondary battery 100. If the voltage difference between the positive and negative electrodes of the secondary battery 100 is lower than the minimum allowable voltage value, the secondary battery 100 can be considered to be in an overdischarged state. The minimum allowable voltage is input as a reference voltage from an input terminal (-), and the other input terminal (+) of the comparator is connected to the circuit signal source of the secondary battery 100 to obtain the current operating voltage of the secondary battery 100. Or the voltage difference between the positive and negative electrodes. The circuit signal source is the discharge control switch pin 124 of the battery management chip 120 of the secondary battery 100, and can also be replaced by the working voltage pin 121. The end of the battery management chip 120 design can be stopped at the secondary battery 100. Under operation, it is possible to provide the aforementioned operating voltage or voltage difference. It should be noted in this embodiment that the potential of the normal voltage is higher than the potential of the release voltage because of the selection of the input terminal; if the reference voltage is exchanged with the input terminal of the operating voltage, the potential of the normal voltage is lower than the potential of the release voltage.

Referring to Figure 6, the operation of the forced charge protection circuit 200 is explained below. In FIG. 6, the operating voltage states H(High) and L(Low) of the secondary battery 100 respectively indicate that the secondary battery 100 is in normal operation or over-discharge, and the output voltages H and L of the comparing unit 240 are respectively The normal voltage and the release voltage output by the comparison unit 240 are indicated, and the voltages H and L of the power supply 260 respectively indicate that the power supply 260 supplies power and stops supplying power.

When the forced charge protection circuit 200 and the secondary battery 100 are in a normal state When connected in the active state, the output voltage of the comparison unit 240 is a normal voltage, the release unit 220 is turned off, the trigger switch 250 is turned off, and the circuit-on switch 210 is turned off. It is to be noted that the power supply 260 is in a supply power state in a state where the forced charging protection circuit 200 is connected to the secondary battery 100, so that the forced charging protection circuit 200 can operate efficiently.

When the time comes to t1, the secondary battery 100 is in the case of overdischarge, the discharge control switch 140 is turned off, and the circuit when the secondary battery 100 is discharged is opened at the discharge control switch 140. The line connected by the forced charging protection circuit 200 (between the node 100c and the node 100d) forms a bypass connection. At this time, the voltage difference provided by the circuit signal source is lower than the lowest allowable voltage value, and the output voltage of the comparison unit 240 is changed to a low potential, that is, the release voltage is supplied to the release unit 220, and the release unit 220 is turned on. However, since the trigger switch 250 is turned off, the trigger unit 230 does not receive the trigger signal, the circuit-on switch 210 and the release unit 220 are not connected, and the circuit-on switch 210 is in a closed state. When the time comes to t2, the trigger switch 250 is turned on, and the circuit conduction switch 210 and the release unit 220 are in electrical communication state. At this time, the circuit-on switch 210 is turned on, and the node 100c is short-circuited between the nodes 100d, and the charger can be forcibly charged by the terminal unit 150 for charging the secondary battery 100.

When the voltage difference between the positive and negative electrodes of the secondary battery 100 rises after a period of charging, the bypass connection should be canceled, and the operation of the secondary battery 100 is returned to the battery management wafer 120 for processing. At t3, the voltage difference provided by the circuit signal source is higher than the lowest allowable voltage value, and the comparison unit 240 replies The normal voltage is supplied to the release unit 220, and the release unit 220 is not grounded. As a result, the circuit-on switch 210 is turned off, and the node 100c to the node 100d cannot be electrically connected by the bypass connection. If the secondary battery 100 continues to charge the charger, the battery management wafer 120 will open the discharge control switch 140 because the secondary battery 100 is already at the normal operating voltage, so that the voltage difference between the positive and negative electrodes of the secondary battery 100 continues to rise. The trigger switch 250 is not in a hurry to turn off t3, and can wait until later (t4) to turn it off. Because the release unit 220 is not conducting ground, the switching state of the trigger switch 250 between t3 and t4 does not affect the state in which the circuit-on switch 210 remains off.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any person skilled in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of protection of this creation is subject to the definition of the scope of the patent application attached.

200‧‧‧Forced charging protection circuit

210‧‧‧Circuit conduction switch

220‧‧‧ release unit

230‧‧‧Trigger unit

240‧‧‧Comparative unit

250‧‧‧Trigger switch

260‧‧‧Power supply

261‧‧‧Power circuit

Claims (10)

A forced charging protection circuit for over-discharging of a secondary battery, comprising: a circuit-on switch, connected in parallel with a charging control switch and a discharge control switch connected in series in a secondary battery, and being electrically connected a release unit for conducting a ground after receiving a release voltage; a trigger unit connected to the circuit conduction switch and the release unit for conducting a switch and a release unit after receiving a trigger signal And a comparison unit electrically connected to the secondary battery, comparing a voltage difference between the positive electrode and the negative electrode of the secondary battery and a minimum allowable voltage value; when the voltage difference is greater than a minimum allowable voltage value, providing a normal voltage Giving the release unit; when the voltage difference is less than the minimum allowable voltage value, providing a release voltage to the release unit; wherein the circuit is turned on when the release unit is turned on and the trigger unit turns on the electrical connection between the circuit conduction switch and the release unit, the circuit The on switch is turned on. The forced charging protection circuit of claim 1, wherein the triggering unit is further connected to a triggering switch, and the triggering signal is sent to the triggering unit when the triggering switch is turned on. The forced charging protection circuit of claim 2, wherein the triggering unit is a controlled rectifier. For example, the forced charging protection circuit described in claim 3, wherein A gate of the voltage controlled rectifier is connected to the trigger switch, and when the trigger switch is turned on, the gate receives a high potential voltage. The forced charging protection circuit of claim 1, further comprising a power source connected to the circuit conduction switch for providing power required for the circuit to operate the switch. The forced charging protection circuit of claim 1, wherein the comparing unit is a comparator. The forced charging protection circuit of claim 6, wherein an input of the comparator is connected to a circuit signal source of the secondary battery. The forced charge protection circuit of claim 7, wherein the circuit signal source is a discharge control switch pin or an operating voltage pin (VDD) of the battery management chip of the secondary battery. The forced charging protection circuit of claim 1, wherein the release unit comprises a field effect transistor and a parasitic diode. The forced charging protection circuit of claim 1, wherein the circuit conduction switch is an optical coupling relay.